Re: [time-nuts] Using a common power supply among few time standards
Hi Unless there is something wrong with the linear supply, it will produce heat proportional to the output load. They all have very low “parasitic” current in the control circuits. A unit with a damaged transformer or bad caps *can* indeed heat up with no load. In that case, it needs to be repaired. Bob > On Feb 12, 2020, at 10:34 PM, Taka Kamiya via time-nuts > wrote: > > Yes, I did consider use of a second linear supply for 12V. But decided > against it. This particular project was to use ONE 24V supply only. This is > because of my previous project. Also the issue with another 12V linear is > that these open frame supplies are awfully inefficient. They generate > enormous amount of heat for little current. Since this is a rubidium box, > heat management was important. > > On previous project, I used 24V linear supply, and 12V switcher supply. AND > 5V DC/DC off 24V, 5V 3 terminal off 12v, and 3.3V internal to one device. > Each was routed all over the place. The end result was a good working > system. But ground situation became very complicated. I was very concerned > because EFC can easily be affected. > > This is still a work in progress. There is already a plan for 3rd iteration > with GPDSO, and 4th iteration with OCXO. I'd expect similar problems. I'm > still debating a good design as OCXO requires +/-5V supply that has to be > very clean and stable. > > At one point, I plan to remake the first project. Besides the fact it works, > I didn't practice good engineering process. Lack of foresight and slapping > on STUFF as needed led to this awful configuration. There got to be a much > better way, and I got to get there for my own satisfaction. > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > >On Wednesday, February 12, 2020, 9:49:42 PM EST, Charles Steinmetz > wrote: > > Taka Kamiya wrote: > >> I started with 24V linear power supply (open frame type). This is the only >> power supply in the box. From there, it branches to Rb, a small dist amp, >> and a simple interface circuit. Dist amp is 12V rated and interface is 5V. >> I modified the dist amp by including a 3 terminal regulator. * * * I >> crated a 5V source right at Rb's interface board to be used as EFC power. >> This is the only purpose of this branch. I also created a separate 5V for >> the simple interface circuit. >> >> * * * EFC circuit was fine but digital interface board killed the >> regulator. Put a heat sink on it and issue is resolved. A bit surprising >> but it shouldn't be The circuit only uses 25mA or so but voltage drop >> is huge. * * * I will have to consider use of small smp board for large >> voltage drops. > > Good idea to use two, 5 V supplies in this situation. > > The EFC circuit presumably draws no more than 0.5 mA, so regulator power > dissipation is probably at most 19 V x 0.5 mA, or <10 mW. As you found, > no problem. > > At ~ 25 mA, the interface board dissipates ~ 19 V x 25 mA, or ~ 500 mW. > As you found, nothing a moderate heatsink can't handle. But you don't > have to dissipate all 500 mW in the regulator. For example, you could > feed the 5 V regulator from the 24 V supply through a 400 ohm, 1 W > resistor (putting a capacitor of, say, 470 uF to ground at the input of > the 5 V reg). This would share the ~500 mW dissipation equally between > the 5 V regulator and the resistor. (A 10v, 1 W zener diode would also > work.) > > Another option would be to use two, mains-powered linear power supplies > -- one 24v supply, and one 12v supply. Then sub-regulate the two 5v > supplies from the 12v supply rather than from 24v. > >> My only remaining concern is if regulator fails short, then what happens?? >> It will kill the particular device, which I'm fine with, but what else? >> Perhaps simple fuse is in order for every branch. > > A fuse by itself will not necessarily open in this situation. If you > are worried about failing short, use a simple zener diode crowbar with > the protective fuse. Use a shunt zener with a breakdown voltage about > 2v greater than the regulated power supply voltage across the load, fed > through the protective fuse. The fuse should be rated at about 200% of > the load current. The zener must be sufficiently robust to withstand > the fault current until the fuse opens. > > With a zener rated 2v greater than the operating voltage, there is a > good chance the downstream load will survive without damage. > > Best regards, > > Charles > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to >
Re: [time-nuts] Using a common power supply among few time standards
Yes, I did consider use of a second linear supply for 12V. But decided against it. This particular project was to use ONE 24V supply only. This is because of my previous project. Also the issue with another 12V linear is that these open frame supplies are awfully inefficient. They generate enormous amount of heat for little current. Since this is a rubidium box, heat management was important. On previous project, I used 24V linear supply, and 12V switcher supply. AND 5V DC/DC off 24V, 5V 3 terminal off 12v, and 3.3V internal to one device. Each was routed all over the place. The end result was a good working system. But ground situation became very complicated. I was very concerned because EFC can easily be affected. This is still a work in progress. There is already a plan for 3rd iteration with GPDSO, and 4th iteration with OCXO. I'd expect similar problems. I'm still debating a good design as OCXO requires +/-5V supply that has to be very clean and stable. At one point, I plan to remake the first project. Besides the fact it works, I didn't practice good engineering process. Lack of foresight and slapping on STUFF as needed led to this awful configuration. There got to be a much better way, and I got to get there for my own satisfaction. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Wednesday, February 12, 2020, 9:49:42 PM EST, Charles Steinmetz wrote: Taka Kamiya wrote: > I started with 24V linear power supply (open frame type). This is the only > power supply in the box. From there, it branches to Rb, a small dist amp, > and a simple interface circuit. Dist amp is 12V rated and interface is 5V. > I modified the dist amp by including a 3 terminal regulator. * * * I > crated a 5V source right at Rb's interface board to be used as EFC power. > This is the only purpose of this branch. I also created a separate 5V for > the simple interface circuit. > > * * * EFC circuit was fine but digital interface board killed the >regulator. Put a heat sink on it and issue is resolved. A bit surprising but >it shouldn't be The circuit only uses 25mA or so but voltage drop is >huge. * * * I will have to consider use of small smp board for large >voltage drops. Good idea to use two, 5 V supplies in this situation. The EFC circuit presumably draws no more than 0.5 mA, so regulator power dissipation is probably at most 19 V x 0.5 mA, or <10 mW. As you found, no problem. At ~ 25 mA, the interface board dissipates ~ 19 V x 25 mA, or ~ 500 mW. As you found, nothing a moderate heatsink can't handle. But you don't have to dissipate all 500 mW in the regulator. For example, you could feed the 5 V regulator from the 24 V supply through a 400 ohm, 1 W resistor (putting a capacitor of, say, 470 uF to ground at the input of the 5 V reg). This would share the ~500 mW dissipation equally between the 5 V regulator and the resistor. (A 10v, 1 W zener diode would also work.) Another option would be to use two, mains-powered linear power supplies -- one 24v supply, and one 12v supply. Then sub-regulate the two 5v supplies from the 12v supply rather than from 24v. > My only remaining concern is if regulator fails short, then what happens?? > It will kill the particular device, which I'm fine with, but what else? > Perhaps simple fuse is in order for every branch. A fuse by itself will not necessarily open in this situation. If you are worried about failing short, use a simple zener diode crowbar with the protective fuse. Use a shunt zener with a breakdown voltage about 2v greater than the regulated power supply voltage across the load, fed through the protective fuse. The fuse should be rated at about 200% of the load current. The zener must be sufficiently robust to withstand the fault current until the fuse opens. With a zener rated 2v greater than the operating voltage, there is a good chance the downstream load will survive without damage. Best regards, Charles ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Taka Kamiya wrote: I started with 24V linear power supply (open frame type). This is the only power supply in the box. From there, it branches to Rb, a small dist amp, and a simple interface circuit. Dist amp is 12V rated and interface is 5V. I modified the dist amp by including a 3 terminal regulator. * * * I crated a 5V source right at Rb's interface board to be used as EFC power. This is the only purpose of this branch. I also created a separate 5V for the simple interface circuit. * * * EFC circuit was fine but digital interface board killed the regulator. Put a heat sink on it and issue is resolved. A bit surprising but it shouldn't be The circuit only uses 25mA or so but voltage drop is huge. * * * I will have to consider use of small smp board for large voltage drops. Good idea to use two, 5 V supplies in this situation. The EFC circuit presumably draws no more than 0.5 mA, so regulator power dissipation is probably at most 19 V x 0.5 mA, or <10 mW. As you found, no problem. At ~ 25 mA, the interface board dissipates ~ 19 V x 25 mA, or ~ 500 mW. As you found, nothing a moderate heatsink can't handle. But you don't have to dissipate all 500 mW in the regulator. For example, you could feed the 5 V regulator from the 24 V supply through a 400 ohm, 1 W resistor (putting a capacitor of, say, 470 uF to ground at the input of the 5 V reg). This would share the ~500 mW dissipation equally between the 5 V regulator and the resistor. (A 10v, 1 W zener diode would also work.) Another option would be to use two, mains-powered linear power supplies -- one 24v supply, and one 12v supply. Then sub-regulate the two 5v supplies from the 12v supply rather than from 24v. My only remaining concern is if regulator fails short, then what happens?? It will kill the particular device, which I'm fine with, but what else? Perhaps simple fuse is in order for every branch. A fuse by itself will not necessarily open in this situation. If you are worried about failing short, use a simple zener diode crowbar with the protective fuse. Use a shunt zener with a breakdown voltage about 2v greater than the regulated power supply voltage across the load, fed through the protective fuse. The fuse should be rated at about 200% of the load current. The zener must be sufficiently robust to withstand the fault current until the fuse opens. With a zener rated 2v greater than the operating voltage, there is a good chance the downstream load will survive without damage. Best regards, Charles ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
I spent last two days boxing up LPRO-101 into a 2U rack case. It has Rb, dist amp, interface for LED, and EFC knob on front. While doing so, I gave power supply concern I have been discussing careful thought. I believe I came to something that is workable and fits my needs. I started with 24V linear power supply (open frame type). This is the only power supply in the box. From there, it branches to Rb, a small dist amp, and a simple interface circuit. Dist amp is 12V rated and interface is 5V. I modified the dist amp by including a 3 terminal regulator. Now, it's a 24V device. I crated a 5V source right at Rb's interface board to be used as EFC power. This is the only purpose of this branch. I also created a separate 5V for the simple interface circuit. The reason for two 5V supply is that I didn't want to mix the source for EFC and digital circuit together. Pretty quickly, I found out going from 24V to 5V incurs huge loss resulting in heat and death of 3 terminal regulator for that branch. EFC circuit was fine but digital interface board killed the regulator. Put a heat sink on it and issue is resolved. A bit surprising but it shouldn't be The circuit only uses 25mA or so but voltage drop is huge. Basically, I'm doing the same thing S100 bus computers did. I will have to consider use of small smp board for large voltage drops. I didn't this time, as its noise profile is not known to me. Can't really go wrong with linear regulators. My only remaining concern is if regulator fails short, then what happens?? It will kill the particular device, which I'm fine with, but what else? Perhaps simple fuse is in order for every branch. This method is a lot simpler than hap-haphazardly creating multiple voltage at power supply and routing all over the place. It became impossible to trace ground loops. Above method makes it really easy as, as far as power supply is concerned, everything is a 24V device. Thanks everyone for discussions. I learned a lot in this process. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Saturday, February 8, 2020, 9:52:02 PM EST, Charles Steinmetz wrote: Chris wrote: > How about using the open frame linear supplies like the ones from Power One > or Lambda? I have had very good results with Deltron open-frame linear supplies. They have selectable mains voltage and low output noise (1mVrms/5mVp-p). I have used many (i.e., hundreds) of the Model W303E triple-output supply. These have one, 5v/8A section and two sections, each selectable between 5v/12v/15v at 0.7A/1.7A/1.5A. [*NOTE* there is an overall 55W output limit, so they will not do all of that at once.] Each section can be adjusted +/- 5%. These show up regularly on ebay. As for switchers, I have been satisfied with the performance of Integrated Power Designs (IPD) products. [IPD is a different company than Power Designs, who made some of the best lab and bench power supplies of the 1960s through 1990s.] One in particular may be of interest to time nuts: the Model SRW-65-4006. This is a four-output supply (5v/5A, 24v/1A, and +/-15v/2A) [*NOTE* again, there is a 65W overall limit, so it won't do all of that at once]. It is available open-frame or with a chassis and cover. For installation close to other circuitry, and particularly inside a piece of equipment, I strongly recommend the model with both chassis and cover (options CH and CO). Check ebay and look at distributors. Assume you will need to post-filter the switcher output, either with L/C filters or low noise linear regulators. Note that I did not say "LDOs". I don't know why, but everyone seems to be stuck on LDOs these days. Active regulators (including LDOs) *always* perform better with more headroom (up to 4v or so). The only excuse for designing LDO is if you have a gun to your head from a power budget you can't otherwise control. [Here, "LDO" is mostly a matter of how you use the part, not of its claimed capabilities -- "LDO" regulators work much better with at least 4v of headroom.] Best regards, Charles ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Chris wrote: How about using the open frame linear supplies like the ones from Power One or Lambda? I have had very good results with Deltron open-frame linear supplies. They have selectable mains voltage and low output noise (1mVrms/5mVp-p). I have used many (i.e., hundreds) of the Model W303E triple-output supply. These have one, 5v/8A section and two sections, each selectable between 5v/12v/15v at 0.7A/1.7A/1.5A. [*NOTE* there is an overall 55W output limit, so they will not do all of that at once.] Each section can be adjusted +/- 5%. These show up regularly on ebay. As for switchers, I have been satisfied with the performance of Integrated Power Designs (IPD) products. [IPD is a different company than Power Designs, who made some of the best lab and bench power supplies of the 1960s through 1990s.] One in particular may be of interest to time nuts: the Model SRW-65-4006. This is a four-output supply (5v/5A, 24v/1A, and +/-15v/2A) [*NOTE* again, there is a 65W overall limit, so it won't do all of that at once]. It is available open-frame or with a chassis and cover. For installation close to other circuitry, and particularly inside a piece of equipment, I strongly recommend the model with both chassis and cover (options CH and CO). Check ebay and look at distributors. Assume you will need to post-filter the switcher output, either with L/C filters or low noise linear regulators. Note that I did not say "LDOs". I don't know why, but everyone seems to be stuck on LDOs these days. Active regulators (including LDOs) *always* perform better with more headroom (up to 4v or so). The only excuse for designing LDO is if you have a gun to your head from a power budget you can't otherwise control. [Here, "LDO" is mostly a matter of how you use the part, not of its claimed capabilities -- "LDO" regulators work much better with at least 4v of headroom.] Best regards, Charles ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
I *just* put pieces together for my project. It's in a 2U rack case. AND REALIZED RACK FLANGE IS ON BACK PANEL! Geez... Now, I have to re-drill some holes and turn it around. This particular case has integrated flange. It's part of the side panel - and power supply is mounted there. I can't believe I did that. Bert, I saw some advertisement on Amazon where other companies are starting to use MW logo and Mean Well name on their product. When I looked at it, it was clear the unit itself isn't MeanWell. I'm thinking before too long, there will be counterfeit one floating around I guess the name and reputation is starting to develop and unethical companies are piggy backing on their name. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Saturday, February 8, 2020, 5:59:12 PM EST, ew via time-nuts wrote: Thank you for your warning. Have not bought Traco but was considered after Poul-Henning recommendation. Will stay with Mean Well have plenty good experience, a couple % more efficiency was tempting no more Bert Kehren In a message dated 2/8/2020 4:43:02 PM Eastern Standard Time, megaflu...@gmail.com writes: Hi Bert, Make sure to measure the noise on the Traco (on both input and output) We had some issue with noise from a couple of Traco models at work. We changed to Mean Well, and much less noise Br, Askild On Sat, Feb 8, 2020 at 8:10 PM ew via time-nuts wrote: > Just got this in the mail I am sure they have related items. > We use with very good results Mean Well SD DC/DC products, for my Rb 8607 > project I plan on using Traco Power > > https://www.maximintegrated.com/en/design/reference-design-center/ref-circuits/7055.html?utm_source=Eloqua_medium=email_content=REFDES1234_campaign=FY20_Q3_2020_FEB_ALL-BU_AMER_EE-Mail_EN > Bert Kehren > > In a message dated 2/8/2020 11:45:09 AM Eastern Standard Time, > kd4...@gmail.com writes: > > Hi Taka, > > How about using the open frame linear supplies like the ones from Power > One or Lambda? > I usually pick these up when I find them, recap if needed and they're a > cheap and easy way to get a supply. > > Chris > KD4PBJ > > > On Feb 6, 2020, at 4:29 PM, Taka Kamiya via time-nuts < > time-nuts@lists.febo.com> wrote: > > > > I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, > etc, etc. I don't mean making of these from scratch but taking a surplus > unit and encase them in ready-to-use form. Most of them are in U2 rack > case. > > > > One part of it that I really do not like is constructing a power supply > for each and every unit I make. Good power supplies are essential to clean > and stable timebase, I know. It is also heat generating as most of what I > make use linear regulators. But it's tedious and mandane to do it every > single time! So, I wanted to make a large enough power supply to provide > +24V, +/- 12V, and 5V. My plan was to have independent feed line for each > timebase unit. > > Is this even a good idea? I have no experience in this to make a > reasonable judgement. This plan would mean these power voltages will be > fed to each components without any local regulation. While I do plan to > put ferrite chokes and bypass capacitors at input, but since the whole > point is to eliminate local power supply components, there will be nothing > else in terms of isolation. > > Similarly, I was also thinking of having a large battery bank for 24 > volt supply. What type of battery is irrelevant and so as charging method > for this question. I have heard of this being done. But for units that > require 24 volts, that means there is no room for any type of regulation. > Most 24V batteries output varying voltage depending on state of charging. > I know 12V battery can produce as high as 13.x volt. Is anyone doing this > type of thing on this list? If so, would you be willing to share details? > > > > Appreciate any input. > > > > --- > > (Mr.) Taka Kamiya > > KB4EMF / ex JF2DKG > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Thank you for your warning. Have not bought Traco but was considered after Poul-Henning recommendation. Will stay with Mean Well have plenty good experience, a couple % more efficiency was tempting no more Bert Kehren In a message dated 2/8/2020 4:43:02 PM Eastern Standard Time, megaflu...@gmail.com writes: Hi Bert, Make sure to measure the noise on the Traco (on both input and output) We had some issue with noise from a couple of Traco models at work. We changed to Mean Well, and much less noise Br, Askild On Sat, Feb 8, 2020 at 8:10 PM ew via time-nuts wrote: > Just got this in the mail I am sure they have related items. > We use with very good results Mean Well SD DC/DC products, for my Rb 8607 > project I plan on using Traco Power > > https://www.maximintegrated.com/en/design/reference-design-center/ref-circuits/7055.html?utm_source=Eloqua_medium=email_content=REFDES1234_campaign=FY20_Q3_2020_FEB_ALL-BU_AMER_EE-Mail_EN > Bert Kehren > > In a message dated 2/8/2020 11:45:09 AM Eastern Standard Time, > kd4...@gmail.com writes: > > Hi Taka, > > How about using the open frame linear supplies like the ones from Power > One or Lambda? > I usually pick these up when I find them, recap if needed and they're a > cheap and easy way to get a supply. > > Chris > KD4PBJ > > > On Feb 6, 2020, at 4:29 PM, Taka Kamiya via time-nuts < > time-nuts@lists.febo.com> wrote: > > > > I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, > etc, etc. I don't mean making of these from scratch but taking a surplus > unit and encase them in ready-to-use form. Most of them are in U2 rack > case. > > > > One part of it that I really do not like is constructing a power supply > for each and every unit I make. Good power supplies are essential to clean > and stable timebase, I know. It is also heat generating as most of what I > make use linear regulators. But it's tedious and mandane to do it every > single time! So, I wanted to make a large enough power supply to provide > +24V, +/- 12V, and 5V. My plan was to have independent feed line for each > timebase unit. > > Is this even a good idea? I have no experience in this to make a > reasonable judgement. This plan would mean these power voltages will be > fed to each components without any local regulation. While I do plan to > put ferrite chokes and bypass capacitors at input, but since the whole > point is to eliminate local power supply components, there will be nothing > else in terms of isolation. > > Similarly, I was also thinking of having a large battery bank for 24 > volt supply. What type of battery is irrelevant and so as charging method > for this question. I have heard of this being done. But for units that > require 24 volts, that means there is no room for any type of regulation. > Most 24V batteries output varying voltage depending on state of charging. > I know 12V battery can produce as high as 13.x volt. Is anyone doing this > type of thing on this list? If so, would you be willing to share details? > > > > Appreciate any input. > > > > --- > > (Mr.) Taka Kamiya > > KB4EMF / ex JF2DKG > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Hi Bert, Make sure to measure the noise on the Traco (on both input and output) We had some issue with noise from a couple of Traco models at work. We changed to Mean Well, and much less noise Br, Askild On Sat, Feb 8, 2020 at 8:10 PM ew via time-nuts wrote: > Just got this in the mail I am sure they have related items. > We use with very good results Mean Well SD DC/DC products, for my Rb 8607 > project I plan on using Traco Power > > https://www.maximintegrated.com/en/design/reference-design-center/ref-circuits/7055.html?utm_source=Eloqua_medium=email_content=REFDES1234_campaign=FY20_Q3_2020_FEB_ALL-BU_AMER_EE-Mail_EN > Bert Kehren > > In a message dated 2/8/2020 11:45:09 AM Eastern Standard Time, > kd4...@gmail.com writes: > > Hi Taka, > > How about using the open frame linear supplies like the ones from Power > One or Lambda? > I usually pick these up when I find them, recap if needed and they're a > cheap and easy way to get a supply. > > Chris > KD4PBJ > > > On Feb 6, 2020, at 4:29 PM, Taka Kamiya via time-nuts < > time-nuts@lists.febo.com> wrote: > > > > I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, > etc, etc. I don't mean making of these from scratch but taking a surplus > unit and encase them in ready-to-use form. Most of them are in U2 rack > case. > > > > One part of it that I really do not like is constructing a power supply > for each and every unit I make. Good power supplies are essential to clean > and stable timebase, I know. It is also heat generating as most of what I > make use linear regulators. But it's tedious and mandane to do it every > single time! So, I wanted to make a large enough power supply to provide > +24V, +/- 12V, and 5V. My plan was to have independent feed line for each > timebase unit. > > Is this even a good idea? I have no experience in this to make a > reasonable judgement. This plan would mean these power voltages will be > fed to each components without any local regulation. While I do plan to > put ferrite chokes and bypass capacitors at input, but since the whole > point is to eliminate local power supply components, there will be nothing > else in terms of isolation. > > Similarly, I was also thinking of having a large battery bank for 24 > volt supply. What type of battery is irrelevant and so as charging method > for this question. I have heard of this being done. But for units that > require 24 volts, that means there is no room for any type of regulation. > Most 24V batteries output varying voltage depending on state of charging. > I know 12V battery can produce as high as 13.x volt. Is anyone doing this > type of thing on this list? If so, would you be willing to share details? > > > > Appreciate any input. > > > > --- > > (Mr.) Taka Kamiya > > KB4EMF / ex JF2DKG > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Just got this in the mail I am sure they have related items. We use with very good results Mean Well SD DC/DC products, for my Rb 8607 project I plan on using Traco Power https://www.maximintegrated.com/en/design/reference-design-center/ref-circuits/7055.html?utm_source=Eloqua_medium=email_content=REFDES1234_campaign=FY20_Q3_2020_FEB_ALL-BU_AMER_EE-Mail_EN Bert Kehren In a message dated 2/8/2020 11:45:09 AM Eastern Standard Time, kd4...@gmail.com writes: Hi Taka, How about using the open frame linear supplies like the ones from Power One or Lambda? I usually pick these up when I find them, recap if needed and they're a cheap and easy way to get a supply. Chris KD4PBJ > On Feb 6, 2020, at 4:29 PM, Taka Kamiya via time-nuts > wrote: > > I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, etc, > etc. I don't mean making of these from scratch but taking a surplus unit and > encase them in ready-to-use form. Most of them are in U2 rack case. > > One part of it that I really do not like is constructing a power supply for > each and every unit I make. Good power supplies are essential to clean and > stable timebase, I know. It is also heat generating as most of what I make > use linear regulators. But it's tedious and mandane to do it every single > time! So, I wanted to make a large enough power supply to provide +24V, +/- > 12V, and 5V. My plan was to have independent feed line for each timebase > unit. > Is this even a good idea? I have no experience in this to make a reasonable > judgement. This plan would mean these power voltages will be fed to each > components without any local regulation. While I do plan to put ferrite > chokes and bypass capacitors at input, but since the whole point is to > eliminate local power supply components, there will be nothing else in terms > of isolation. > Similarly, I was also thinking of having a large battery bank for 24 volt > supply. What type of battery is irrelevant and so as charging method for > this question. I have heard of this being done. But for units that require > 24 volts, that means there is no room for any type of regulation. Most 24V > batteries output varying voltage depending on state of charging. I know 12V > battery can produce as high as 13.x volt. Is anyone doing this type of thing > on this list? If so, would you be willing to share details? > > Appreciate any input. > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Hi Grab your DVM and take a look at the voltage on the input caps on one of those supplies as compared to the output voltage. With light loads (which is how most use them …) the voltage ratio is pretty high. As a result, the efficiency is not as good as it could be. The Acopian versions that come fully enclosed are no more efficient, but are nicely protected from “stuff". Like the rest, they can be found on eBay for not a lot of money …. Bob > On Feb 8, 2020, at 11:44 AM, Chris Waldrup wrote: > > Hi Taka, > > How about using the open frame linear supplies like the ones from Power One > or Lambda? > I usually pick these up when I find them, recap if needed and they're a cheap > and easy way to get a supply. > > Chris > KD4PBJ > >> On Feb 6, 2020, at 4:29 PM, Taka Kamiya via time-nuts >> wrote: >> >> I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, etc, >> etc. I don't mean making of these from scratch but taking a surplus unit >> and encase them in ready-to-use form. Most of them are in U2 rack case. >> >> One part of it that I really do not like is constructing a power supply for >> each and every unit I make. Good power supplies are essential to clean and >> stable timebase, I know. It is also heat generating as most of what I make >> use linear regulators. But it's tedious and mandane to do it every single >> time! So, I wanted to make a large enough power supply to provide +24V, +/- >> 12V, and 5V. My plan was to have independent feed line for each timebase >> unit. >> Is this even a good idea? I have no experience in this to make a reasonable >> judgement. This plan would mean these power voltages will be fed to each >> components without any local regulation. While I do plan to put ferrite >> chokes and bypass capacitors at input, but since the whole point is to >> eliminate local power supply components, there will be nothing else in terms >> of isolation. >> Similarly, I was also thinking of having a large battery bank for 24 volt >> supply. What type of battery is irrelevant and so as charging method for >> this question. I have heard of this being done. But for units that require >> 24 volts, that means there is no room for any type of regulation. Most 24V >> batteries output varying voltage depending on state of charging. I know 12V >> battery can produce as high as 13.x volt. Is anyone doing this type of >> thing on this list? If so, would you be willing to share details? >> >> Appreciate any input. >> >> --- >> (Mr.) Taka Kamiya >> KB4EMF / ex JF2DKG >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Hi Taka, How about using the open frame linear supplies like the ones from Power One or Lambda? I usually pick these up when I find them, recap if needed and they're a cheap and easy way to get a supply. Chris KD4PBJ > On Feb 6, 2020, at 4:29 PM, Taka Kamiya via time-nuts > wrote: > > I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, etc, > etc. I don't mean making of these from scratch but taking a surplus unit and > encase them in ready-to-use form. Most of them are in U2 rack case. > > One part of it that I really do not like is constructing a power supply for > each and every unit I make. Good power supplies are essential to clean and > stable timebase, I know. It is also heat generating as most of what I make > use linear regulators. But it's tedious and mandane to do it every single > time! So, I wanted to make a large enough power supply to provide +24V, +/- > 12V, and 5V. My plan was to have independent feed line for each timebase > unit. > Is this even a good idea? I have no experience in this to make a reasonable > judgement. This plan would mean these power voltages will be fed to each > components without any local regulation. While I do plan to put ferrite > chokes and bypass capacitors at input, but since the whole point is to > eliminate local power supply components, there will be nothing else in terms > of isolation. > Similarly, I was also thinking of having a large battery bank for 24 volt > supply. What type of battery is irrelevant and so as charging method for > this question. I have heard of this being done. But for units that require > 24 volts, that means there is no room for any type of regulation. Most 24V > batteries output varying voltage depending on state of charging. I know 12V > battery can produce as high as 13.x volt. Is anyone doing this type of thing > on this list? If so, would you be willing to share details? > > Appreciate any input. > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Hi DC/DC converters can indeed be filtered. If you do it wrong, things will get pretty crazy. In general, you need at least an L/C filter and may need an R/L/C design. Things like ESR on the caps and SRF on the inductors do indeed matter. Both common mode and differential mode filtering may be needed. With both inductors and ferrite beads, saturation performance is important. It’s a good idea to only use parts that have detailed data. Three terminal regulators have a *wide* range of PSRR profiles. Some do almost nothing past 1 KHz, others are still doing quite well at 10 MHz. Data sheets are your friend in this case. For best performance, app notes are often a good resource as well. Yes, this *is* circuit design. There are details to it. Test / analysis / rework are all part of the process. That’s the way it’s done …. Bob > On Feb 8, 2020, at 9:59 AM, Taka Kamiya via time-nuts > wrote: > > Right now, my problem is where to strike a reasonable yet good compromise. > I thought of using DC/DC but these are quite noisy, and noise comes from both > ends. I had one powering distribution amplifiers. For an experiment, I > placed a ferrite bead on the output and the whole thing oscillated rail to > rail. (and killed the dist.amp) Also, these things switch at very high > speed where ability of 3 terminal regulators to reduce noise is at minimum. > On the other hand, I was playing with red label T-bolt. This thing has > internal DC/DC converters to take 24V and turn it into +/- 12V and 5V. > Powering it with clean linear supply and a garden variety switcher, output > was equally clean. (at least far below my lab's ability to observe issues) > I saw no difference in output at all. Tech support at SRS demanded I use > linear supply for PRS-10, and declined to discuss further. Yet, I've seen > most DIY implementation uses switcher. I *think* /tvb uses 48V common > supply. I also read a comment on this list, when one is dealing with > time-nut level accuracy and stability, every milli-volt counts. > > I guess I'll have to deal with this on case-by-case basis. (pun intended) > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > >On Saturday, February 8, 2020, 9:11:13 AM EST, jimlux > wrote: > > On 2/7/20 7:01 PM, Taka Kamiya via time-nuts wrote: >> I recall S-100 scheme had an issue of per-board regulator failing short and >> dumping 8V into bus killing rest of the system > > More like the 5V regulator (most likely a trusty 7805 in a TO-3 package) > shorting, applying 8V to all those TTL parts on the board, which die, > and put 8V on the address and data lines. However, I'm not sure that > was a particularly common failure. In many years of working with a lot > of S100 systems, I never had that problem. > >> I am thinking of making use of 28V (aircraft power supply?) regulated power >> supply, and have local linear regulator to created needed voltages. One >> concern is, should I need large amount of 5V then loss will be tremendous. > > Probably a better solution is multiple bulk supplies off line AC then > regulate down. Or a DC/DC from 28V to 8V, then good linear regulator to 5V. > > There's really no way around it, although you can do things like > synchronize all your PWM converters, so if you do get spurs, they're in > consistent places. > > > I just came across an article that discussed magnetic field > sensitivity of LPRO-101. The author ended up relocating the transformer > off-board. (in a different case) A very timely information as this is > what I am actually working on. >> Further comment will be appreciatedTakaTime-nut in training >> --- >> (Mr.) Taka Kamiya >> KB4EMF / ex JF2DKG >> >> >> On Thursday, February 6, 2020, 6:51:38 PM EST, jimlux >> wrote: >> >> On 2/6/20 3:14 PM, Will Kimber wrote: >>> Hi, >>> >>> Usual (best?) is supply slight over voltage and use LDO/RC filtering in >>> each unit as Bob suggested. But that would require either supplying >>> 24v/12v/5v/-12v (with some margin 10%?) or converting some single supply >>> of 24v or 48v in each unit to required voltages at each piece of >>> equipment. The later requires switching supplies to get all voltages. >> >> >> Well that was the strategy used on S-100 boards. Bulk 8V unregulated >> supply regulated down to 5V on the board. >> >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > > >
Re: [time-nuts] Using a common power supply among few time standards
Right now, my problem is where to strike a reasonable yet good compromise. I thought of using DC/DC but these are quite noisy, and noise comes from both ends. I had one powering distribution amplifiers. For an experiment, I placed a ferrite bead on the output and the whole thing oscillated rail to rail. (and killed the dist.amp) Also, these things switch at very high speed where ability of 3 terminal regulators to reduce noise is at minimum. On the other hand, I was playing with red label T-bolt. This thing has internal DC/DC converters to take 24V and turn it into +/- 12V and 5V. Powering it with clean linear supply and a garden variety switcher, output was equally clean. (at least far below my lab's ability to observe issues) I saw no difference in output at all. Tech support at SRS demanded I use linear supply for PRS-10, and declined to discuss further. Yet, I've seen most DIY implementation uses switcher. I *think* /tvb uses 48V common supply. I also read a comment on this list, when one is dealing with time-nut level accuracy and stability, every milli-volt counts. I guess I'll have to deal with this on case-by-case basis. (pun intended) --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Saturday, February 8, 2020, 9:11:13 AM EST, jimlux wrote: On 2/7/20 7:01 PM, Taka Kamiya via time-nuts wrote: > I recall S-100 scheme had an issue of per-board regulator failing short and > dumping 8V into bus killing rest of the system More like the 5V regulator (most likely a trusty 7805 in a TO-3 package) shorting, applying 8V to all those TTL parts on the board, which die, and put 8V on the address and data lines. However, I'm not sure that was a particularly common failure. In many years of working with a lot of S100 systems, I never had that problem. > I am thinking of making use of 28V (aircraft power supply?) regulated power > supply, and have local linear regulator to created needed voltages. One > concern is, should I need large amount of 5V then loss will be tremendous. Probably a better solution is multiple bulk supplies off line AC then regulate down. Or a DC/DC from 28V to 8V, then good linear regulator to 5V. There's really no way around it, although you can do things like synchronize all your PWM converters, so if you do get spurs, they're in consistent places. I just came across an article that discussed magnetic field sensitivity of LPRO-101. The author ended up relocating the transformer off-board. (in a different case) A very timely information as this is what I am actually working on. > Further comment will be appreciatedTakaTime-nut in training > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > > On Thursday, February 6, 2020, 6:51:38 PM EST, jimlux > wrote: > > On 2/6/20 3:14 PM, Will Kimber wrote: >> Hi, >> >> Usual (best?) is supply slight over voltage and use LDO/RC filtering in >> each unit as Bob suggested. But that would require either supplying >> 24v/12v/5v/-12v (with some margin 10%?) or converting some single supply >> of 24v or 48v in each unit to required voltages at each piece of >> equipment. The later requires switching supplies to get all voltages. > > > Well that was the strategy used on S-100 boards. Bulk 8V unregulated > supply regulated down to 5V on the board. > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Hi As you have already noted, things do die from time to time. Fuses are a good idea, along with protection diodes. Still, none of it is 100%. The more heat / temperature you have in a part, the quicker it is likely to fail. One often overlooked failure mode is loosing one supply on a +/-12V pair. If you go back in the archives (yes that’s not easy) there are reports of significant damage on things like DMTD’s from this sort of problem. An open ground also can do the same sort of thing. If everything is AC coupled then a cascade failure is less likely. We run stuff like PPS, serial com, and USB that are very much DC coupled. Having a supply die and kill the entire bench is *not* a good thing. Protection on these signals is worth thinking about. The “honking big supply” comes with great big cables protected by great big fuses. Bump this here or there and a *lot* of energy is involved before the fuse does its thing. Work on trucks or aircraft and you will come up with a lot of data on the sort of damage this can do. These days small power supplies are dirt cheap. DC/DC converter boards also can be had for next to nothing. For a bit more money, fairly good versions can be purchased. For a lot more money, very good ones are out there. Running a bunch of switchers has its drawbacks. Filtering *is* possible. Not every device needs a supply that is at the <1 nv / Hz level. Most devices are fairly tolerant of supply noise. There are a *lot* of systems out there that run with supplies in the 10 mv (rms) range. One size fits all is great for inventory management. It isn’t so great on the credit card. Does a $5 board “deserve” a $500 power setup? At least around here, it’s going to get a $1 wall wart. A $5,000 device may get treated a bit better. If a shiny new / in warranty piece of gear shows up with this or that for power …. it stays that way (at least through the warranty period). If HP “back in the day” thought that this approach was ok for a box I power up < once a month, it’s fine now. The “best answer” to energy savings is still to turn things off. That’s the compelling reason to have external reference inputs on test gear. It’s also a compelling reason to run gear that does not take hours (or days) to warm up and stabilize. With fun stuff like controlled outlets, you can let Alexa manage power to this or that device. Get up in the morning and tell her to warm up the bench. Yes, setting this all up takes some thought and some planning. You may decide you want to have a *lot* of sources on at the same time. Watch out for cross talk. The more sources you have, the more trouble you will get into. Indeed this can become nearly impossible to deal with as you get into the “many thousands” of devices all on the same frequency. We toss around numbers like 120 db of isolation. That’s only adequate at a specific offset and a desired impact on stability…… Lots of directions this can go and lots of choices ….. Bob > On Feb 7, 2020, at 10:01 PM, Taka Kamiya via time-nuts > wrote: > > I recall S-100 scheme had an issue of per-board regulator failing short and > dumping 8V into bus killing rest of the system > I am thinking of making use of 28V (aircraft power supply?) regulated power > supply, and have local linear regulator to created needed voltages. One > concern is, should I need large amount of 5V then loss will be tremendous. I > just came across an article that discussed magnetic field sensitivity of > LPRO-101. The author ended up relocating the transformer off-board. (in a > different case) A very timely information as this is what I am actually > working on. > Further comment will be appreciatedTakaTime-nut in training > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > > >On Thursday, February 6, 2020, 6:51:38 PM EST, jimlux > wrote: > > On 2/6/20 3:14 PM, Will Kimber wrote: >> Hi, >> >> Usual (best?) is supply slight over voltage and use LDO/RC filtering in >> each unit as Bob suggested. But that would require either supplying >> 24v/12v/5v/-12v (with some margin 10%?) or converting some single supply >> of 24v or 48v in each unit to required voltages at each piece of >> equipment. The later requires switching supplies to get all voltages. > > > Well that was the strategy used on S-100 boards. Bulk 8V unregulated > supply regulated down to 5V on the board. > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts
Re: [time-nuts] Using a common power supply among few time standards
On 2/7/20 7:01 PM, Taka Kamiya via time-nuts wrote: I recall S-100 scheme had an issue of per-board regulator failing short and dumping 8V into bus killing rest of the system More like the 5V regulator (most likely a trusty 7805 in a TO-3 package) shorting, applying 8V to all those TTL parts on the board, which die, and put 8V on the address and data lines. However, I'm not sure that was a particularly common failure. In many years of working with a lot of S100 systems, I never had that problem. I am thinking of making use of 28V (aircraft power supply?) regulated power supply, and have local linear regulator to created needed voltages. One concern is, should I need large amount of 5V then loss will be tremendous. Probably a better solution is multiple bulk supplies off line AC then regulate down. Or a DC/DC from 28V to 8V, then good linear regulator to 5V. There's really no way around it, although you can do things like synchronize all your PWM converters, so if you do get spurs, they're in consistent places. I just came across an article that discussed magnetic field sensitivity of LPRO-101. The author ended up relocating the transformer off-board. (in a different case) A very timely information as this is what I am actually working on. Further comment will be appreciatedTakaTime-nut in training --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Thursday, February 6, 2020, 6:51:38 PM EST, jimlux wrote: On 2/6/20 3:14 PM, Will Kimber wrote: Hi, Usual (best?) is supply slight over voltage and use LDO/RC filtering in each unit as Bob suggested. But that would require either supplying 24v/12v/5v/-12v (with some margin 10%?) or converting some single supply of 24v or 48v in each unit to required voltages at each piece of equipment. The later requires switching supplies to get all voltages. Well that was the strategy used on S-100 boards. Bulk 8V unregulated supply regulated down to 5V on the board. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
I recall S-100 scheme had an issue of per-board regulator failing short and dumping 8V into bus killing rest of the system I am thinking of making use of 28V (aircraft power supply?) regulated power supply, and have local linear regulator to created needed voltages. One concern is, should I need large amount of 5V then loss will be tremendous. I just came across an article that discussed magnetic field sensitivity of LPRO-101. The author ended up relocating the transformer off-board. (in a different case) A very timely information as this is what I am actually working on. Further comment will be appreciatedTakaTime-nut in training --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG On Thursday, February 6, 2020, 6:51:38 PM EST, jimlux wrote: On 2/6/20 3:14 PM, Will Kimber wrote: > Hi, > > Usual (best?) is supply slight over voltage and use LDO/RC filtering in > each unit as Bob suggested. But that would require either supplying > 24v/12v/5v/-12v (with some margin 10%?) or converting some single supply > of 24v or 48v in each unit to required voltages at each piece of > equipment. The later requires switching supplies to get all voltages. Well that was the strategy used on S-100 boards. Bulk 8V unregulated supply regulated down to 5V on the board. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
On 2/6/20 3:14 PM, Will Kimber wrote: Hi, Usual (best?) is supply slight over voltage and use LDO/RC filtering in each unit as Bob suggested. But that would require either supplying 24v/12v/5v/-12v (with some margin 10%?) or converting some single supply of 24v or 48v in each unit to required voltages at each piece of equipment. The later requires switching supplies to get all voltages. Well that was the strategy used on S-100 boards. Bulk 8V unregulated supply regulated down to 5V on the board. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Hi, Usual (best?) is supply slight over voltage and use LDO/RC filtering in each unit as Bob suggested. But that would require either supplying 24v/12v/5v/-12v (with some margin 10%?) or converting some single supply of 24v or 48v in each unit to required voltages at each piece of equipment. The later requires switching supplies to get all voltages. Anybody fancy 400Hz or even higher frequency 48v AC supply? Will On 7/02/20 11:52 am, Bob kb8tq wrote: Hi Well, I’m sitting here plotting the stability of some eBay “frequency standards”. The one thing I *can* measure is just when the power cords get bumped. As long as you can hold sub mili-volt sorts of stability on the supplies “as delivered” it pretty much does not matter how you get there. If you get up into the 10’s of mili-volts then it can indeed matter on some devices. Some devices have less sensitivity than others. By the time you get to 100’s of mili-volts, you likley are impacting most devices in a manner you can easily see in the output. Yes, there are a lot of assumptions in all that. The first is that it is a 12V supply and not something odd like 48V. Scale the numbers if you are using an odd voltage. The next Is that the disruption is not simply the lead drop from the oven current. That *will* have an impact, but it’s going to get mixed up with temperature stability. Step / pop / jump sort of changes will come through to the output fairly quickly. Third is that the supply is actually going into something that matters (like an OCXO heater) and not just the supply lead for an opamp. There are a lot more, but they get a bit fiddly …. One alternative is to generate something like 13V and run a good LDO at the “point of use”. Depending on what you find for LDO’s you may be able to get quite close to 12V. The power “wasted” becomes very small in that case. Bob On Feb 6, 2020, at 5:28 PM, Taka Kamiya via time-nuts wrote: I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, etc, etc. I don't mean making of these from scratch but taking a surplus unit and encase them in ready-to-use form. Most of them are in U2 rack case. One part of it that I really do not like is constructing a power supply for each and every unit I make. Good power supplies are essential to clean and stable timebase, I know. It is also heat generating as most of what I make use linear regulators. But it's tedious and mandane to do it every single time! So, I wanted to make a large enough power supply to provide +24V, +/- 12V, and 5V. My plan was to have independent feed line for each timebase unit. Is this even a good idea? I have no experience in this to make a reasonable judgement. This plan would mean these power voltages will be fed to each components without any local regulation. While I do plan to put ferrite chokes and bypass capacitors at input, but since the whole point is to eliminate local power supply components, there will be nothing else in terms of isolation. Similarly, I was also thinking of having a large battery bank for 24 volt supply. What type of battery is irrelevant and so as charging method for this question. I have heard of this being done. But for units that require 24 volts, that means there is no room for any type of regulation. Most 24V batteries output varying voltage depending on state of charging. I know 12V battery can produce as high as 13.x volt. Is anyone doing this type of thing on this list? If so, would you be willing to share details? Appreciate any input. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Using a common power supply among few time standards
Hi Well, I’m sitting here plotting the stability of some eBay “frequency standards”. The one thing I *can* measure is just when the power cords get bumped. As long as you can hold sub mili-volt sorts of stability on the supplies “as delivered” it pretty much does not matter how you get there. If you get up into the 10’s of mili-volts then it can indeed matter on some devices. Some devices have less sensitivity than others. By the time you get to 100’s of mili-volts, you likley are impacting most devices in a manner you can easily see in the output. Yes, there are a lot of assumptions in all that. The first is that it is a 12V supply and not something odd like 48V. Scale the numbers if you are using an odd voltage. The next Is that the disruption is not simply the lead drop from the oven current. That *will* have an impact, but it’s going to get mixed up with temperature stability. Step / pop / jump sort of changes will come through to the output fairly quickly. Third is that the supply is actually going into something that matters (like an OCXO heater) and not just the supply lead for an opamp. There are a lot more, but they get a bit fiddly …. One alternative is to generate something like 13V and run a good LDO at the “point of use”. Depending on what you find for LDO’s you may be able to get quite close to 12V. The power “wasted” becomes very small in that case. Bob > On Feb 6, 2020, at 5:28 PM, Taka Kamiya via time-nuts > wrote: > > I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, etc, > etc. I don't mean making of these from scratch but taking a surplus unit and > encase them in ready-to-use form. Most of them are in U2 rack case. > > One part of it that I really do not like is constructing a power supply for > each and every unit I make. Good power supplies are essential to clean and > stable timebase, I know. It is also heat generating as most of what I make > use linear regulators. But it's tedious and mandane to do it every single > time! So, I wanted to make a large enough power supply to provide +24V, +/- > 12V, and 5V. My plan was to have independent feed line for each timebase > unit. > Is this even a good idea? I have no experience in this to make a reasonable > judgement. This plan would mean these power voltages will be fed to each > components without any local regulation. While I do plan to put ferrite > chokes and bypass capacitors at input, but since the whole point is to > eliminate local power supply components, there will be nothing else in terms > of isolation. > Similarly, I was also thinking of having a large battery bank for 24 volt > supply. What type of battery is irrelevant and so as charging method for > this question. I have heard of this being done. But for units that require > 24 volts, that means there is no room for any type of regulation. Most 24V > batteries output varying voltage depending on state of charging. I know 12V > battery can produce as high as 13.x volt. Is anyone doing this type of thing > on this list? If so, would you be willing to share details? > > Appreciate any input. > > --- > (Mr.) Taka Kamiya > KB4EMF / ex JF2DKG > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Using a common power supply among few time standards
I have been addicted to home brewing GPSDO, Rubidium, OCXO, and etc, etc, etc. I don't mean making of these from scratch but taking a surplus unit and encase them in ready-to-use form. Most of them are in U2 rack case. One part of it that I really do not like is constructing a power supply for each and every unit I make. Good power supplies are essential to clean and stable timebase, I know. It is also heat generating as most of what I make use linear regulators. But it's tedious and mandane to do it every single time! So, I wanted to make a large enough power supply to provide +24V, +/- 12V, and 5V. My plan was to have independent feed line for each timebase unit. Is this even a good idea? I have no experience in this to make a reasonable judgement. This plan would mean these power voltages will be fed to each components without any local regulation. While I do plan to put ferrite chokes and bypass capacitors at input, but since the whole point is to eliminate local power supply components, there will be nothing else in terms of isolation. Similarly, I was also thinking of having a large battery bank for 24 volt supply. What type of battery is irrelevant and so as charging method for this question. I have heard of this being done. But for units that require 24 volts, that means there is no room for any type of regulation. Most 24V batteries output varying voltage depending on state of charging. I know 12V battery can produce as high as 13.x volt. Is anyone doing this type of thing on this list? If so, would you be willing to share details? Appreciate any input. --- (Mr.) Taka Kamiya KB4EMF / ex JF2DKG ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
