Thanks everyone for your help I appreciate it more than you know. I ended
up taking into consideration pretty much everything you suggested. I've
ordered it and will post a finished product in a few weeks...hopefully.
Shep
On Wednesday, April 6, 2016 at 12:23:38 PM UTC-6, gregebert wrote:
>
>
My point wasnt about nixies at all, i just wondered how microchip can supply
this ic, because it would never fit these regulations!
About the ic , HV507 is a 315V 64channel sink-source driver
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Just out of curiosity what Microchip IC is rated at 315V?
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I use the Toshiba TD62083AFN in my Nixie watch as a cathode driver. It sees 50V
between pins on the 0.65mm TSSOP. I take extra care to keep the anode traces
well separated from all the cathode and logic traces on the PC board. I use
.010" (.25mm) trace spacing between cathodes, and .020" (0.5mm)
If you are driving nixie tubes, there actually isn't 300V between pins at
the driver IC. If your supply is 200V, and the typical voltage drop of an
IN-18 is about 140V when illuminated, the actual voltage-difference between
pins is about 60V. That calculates to 0.6mm of spacing, which is still a
About this calculator for insulation... if i type in 300V, i get 2.5mm for
external layers.
So how is it possible for Microchip to sell a 315V rated IC in a PQFP44
case? The pins on a QFP have 0.5mm pitch!
Am Mittwoch, 6. April 2016 20:23:38 UTC+2 schrieb gregebert:
>
> Looks like you have
Looks like you have enough bypass caps; just be sure to place them as close
as possible to the supply pins on the ICs. Good to see you have separate
clk & data lines to the HV5530's; you now have total flexibility to avoid
timing problems.
Be sure to provide enough spacing around high-voltage s
Hello again everyone. Thank you so much for your help with the last version
of my schematic design. After taking all that input into account and doing
some additional research I've redone my design and have posted it below.
Any additional input is welcome if you care to give it. Thanks again.
Sh
Greg,
Thanks for the info, I've taken pretty much all of into account in my
newest version. I indeed did get sockets for when this version inevitably
gets replaced by rev2. I'd be interested in taking a look at that .stl file
and maybe give it a print if you don't mind sharing.
Shep
On Thurs
Forgot to mention this: Tube sockets
As you know, IN-18's are getting rather expensive so you need to be very
gentle with them.
I decided to use socket-pins soldered onto the PC board (inexpensive &
available on Ebay), rather than actual 'sockets', because my past
experience with nixie-tube so
You definitely want to use a level-shifter for reliable operation. I just
finished a 14-tube nixie clock with HV5530's driven from an FPGA; I use
a MC14504. Some people on this forum have driven HV5530's without a
level-shifter; to me saving a few dollars on parts is silly compared to
spending
Hi Jonathan,
Okay I'll check out that page and see if I can understand why changing
those values would be better. As per gregeberts recommendation above I have
already reworked my design and put in the HV5530. I have 12V coming in from
a wallwart to the power supplies and right now I just have
Hello Shep
Some words about the power supply.
I would change the inductor to a higher value, about 100uH. And RSENSE to
0.05R, which could deliver about 50mA.
C4 is fine, but 4,7u would be enough.
Here is a very fine and detailed power supply using the MAX1771
http://desmith.net/NMdS/Elect
Hello Jonathan,
I may eventually end up using a fixed voltage regulator but the reason I
have an LM317 in this schematic is that I already have these and necessary
resistors so it was mainly just to keep cost down. And that's an excellent
point about multiplexing that I hadn't really though of
What parts do you intend to use for the power supply?
If you want to save parts, use a 7805 regulator for the 5V, you don't need
R1, R2,PC2 then.
About Multiplexing, if you have a 1:6 Multiplex, then every tube is only
one sixth of the time on, resulting in lower brightness. A IN-18 is
specif
Yes, a saturated transistor behaves similar to a short-circuit, but in
order to do so it must still be properly biased.
The basic rule is: a bipolar transistor will conduct collector current when
the base-emitter junction is forward-biased.
For an NPN transistor, the base & collector both need
David and gregebert,
Thanks for your replies, they were very helpful. It seems I have had a
somewhat profound misunderstanding of the operation of transistors but I've
spent the last few hours looking at the schematic David referenced as well
as other articles and youtube videos and I'm beginnin
Sorry, I meant to say a PNP transistor with emitter tied to 180V rail.
On 3/29/2016 3:23 PM, David Forbes wrote:
Shep,
There are two polarities of transistors, NPN and PNP. NPN requires the base to
always be 0.6V more positive than the emitter, and PNP requires the base to be
0.6V more negativ
Circuit-wise, the NPN's T1 thru T6 are emitter-followers. In order to turn
them on, the base-emitter junction needs to be forward-biased, which is
about +0.7 volts. So, if the base is driven to +5v (the max possible from
the 74HC device), the max-possible voltage at the emitter will be 5.0-0.7 =
Shep,
There are two polarities of transistors, NPN and PNP. NPN requires the base to
always be 0.6V more positive than the emitter, and PNP requires the base to be
0.6V more negative than the emitter.
The anode must be controlled from the 180V point, not from the 0V point. The
most straight-
Hi gregebert!
Thank you so much for your reply. I've taken a look at the datasheet for
the HV5530 and it seems like it's a no brainer to use this instead of the
transistors to simplify things so I will be taking some time to modify
that. However, I do have a few follow up questions about some t
Welcome to an addictive hobby!
The anode-driver will need some rework because the NPNs (T1 thru T6) will
only drive-out 4.3V (5v I/O from the ATMega, minus 0.7Vbe = 4.3V) as the
circuit is shown. With multiplexing, you will need what's known as a
'high-side driver', and often that is done wit
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