I agree. It's probably very unlikely that you'll damage an output by simply
pulling too much current. I guess the internal resistance is too high to
cause immediate destruction of the output FET. I didn't have any problems
with the logic either. Just too high voltage drop across the '595
Regarding using the 74HC595s, it's true that they are technically out of
spec if too many segments are on, but I believe the failure cause would be
whole chip heating rather than the single output transistors, and
especially with the PWM dimming going on (the segments are never on 100%,
since
I’ve had great experience with the TPIC6B595s, I used them to drive a whole
bunch of miniature bayonet style bulbs for a clock using IEE one plane
readouts, no problems with them so far. Probably a little over 120 mA per IC.
> On Aug 17, 2022, at 8:12 PM, Christian Riise Wagner
> wrote:
>
>
Even running more than 3 segments @20mA is actually out of spec as the
maximum ground and source current for the 74HC595 is 70mA. I found that it
didn't work satisfactory for an IV-19. Too high a voltage drop. Might be
okay for smaller numitrons though. I've ordered some TPIC6C595 instead to
Don't numitrons have pretty high shoot-through current? I'd expect 100mA of
current going into the IC pins at each off-on transition. Which would
probably be fine since it's only for a few milliseconds and as you
mentioned it's been fine for years, but it's technically out of spec.
On Monday,
If bit-banging is done serially, you can avoid most timing problems
by-design. However, if the controller has an 8-bit parallel-output port,
and data is changed on the same cycle as your sampling clock-edge (usually
rising-edge, but HV5530 and similar use falling-edge) you create a race
I almost invariably use daisy-chained 74HC595s in my clocks. I use
Numitrons rather than Nixies, which can be direct-driven with 5 volts, and
an 8051 variant (AT89C4051) because I have lots of them and a tool chain
I'm comfortable with; they're programmed in C. To drive the clock, data,
and
The most sensible low-cost direct drive arrangement in terms of parts count
and board layout is SOIC 74HC595 shift registers and SN75468 HV driver
arrays.
There's a Chinese Zirrfa 6 digit clock board that uses this approach.
On Mon, Aug 15, 2022, 7:09 AM David Pye wrote:
> Given the price of
gt;> measurement tools).
>>
>> Thanks everyone for jumping in with so many suggestions.
>>
>> I'll send a pic of my clock when ready.
>>
>>
>>
>> Original message
>> From: "SWISSNIXIE - Jonathan F."
>> Dat
>
> Of course with 8 steppers * 4 wires each…. It’s a jumbled mess in
> prototyping.
>
>
>
> Michail
>
>
>
> *From:* neoni...@googlegroups.com *On Behalf
> Of *Richard Scales
> *Sent:* Saturday, August 13, 2022 9:42 PM
> *To:* neonixie-l
> *Subjec
@googlegroups.com On Behalf Of
Richard Scales
Sent: Saturday, August 13, 2022 9:42 PM
To: neonixie-l
Subject: Re: [neonixie-l] Re: Nixie Clock - Direct Drive HV5530
I've used HV5522 and HV5622 a lot without any issue - I always use a CD40109B
level shifter to convert from 3v3V or 5V to 12V (I know many do
ping in with so many suggestions.
>
> I'll send a pic of my clock when ready.
>
>
>
> Original message
> From: "SWISSNIXIE - Jonathan F."
> Date: 13/08/2022 22:16 (GMT+00:00)
> To: neonixie-l
> Subject: Re: [neonixie-l] R
and measurement tools). Thanks
everyone for jumping in with so many suggestions. I'll send a pic of my clock
when ready.
Original message From: "SWISSNIXIE - Jonathan F."
Date: 13/08/2022 22:16 (GMT+00:00) To: neonixie-l
Subject: Re: [neonixie-l] Re: Nixie Clock -
Direct Dr
code is open source, I'll just use that otherwise I'll adapt mine
> to use hv5530 and hef4104.
>
> Awesome!
>
>
> Original message
> From: "SWISSNIXIE - Jonathan F."
> Date: 13/08/2022 20:51 (GMT+00:00)
> To: neonixie-l
> Subject:
!
Original message From: "SWISSNIXIE - Jonathan F."
Date: 13/08/2022 20:51 (GMT+00:00) To: neonixie-l
Subject: Re: [neonixie-l] Re: Nixie Clock -
Direct Drive HV5530 The time to shift out the bits is not critical, the clock
rate is as fast as you implement it, the
Thanks. So, that confirms that multiplexing reduces brightness. Which makes
sense now that I start to understand how the HV5530 works.
Original message From: Bill Stanley
Date: 13/08/2022 21:00 (GMT+00:00) To: neonixie-l
Subject: Re: [neonixie-l] Re: Nixie Clock -
Direct
From: "SWISSNIXIE - Jonathan F."
Date: 13/08/2022 20:51 (GMT+00:00) To: neonixie-l
Subject: Re: [neonixie-l] Re: Nixie Clock -
Direct Drive HV5530 The time to shift out the bits is not critical, the clock
rate is as fast as you implement it, there is only a minimum
I believe the shift register speed is rated to 8mhz in these series of HV
shift registers. But its not usually a problem since most people will
probably not drive them that fast.
I did run a similar chip,the HV5122 at 5v with a 3.3v logic input (!) on a
prototype of my last clock. It worked OK
Using the high voltage serial to parallel part (I use the HV5812PJ-G ) is
direct drive in that the NIXIE digits are driven with a stable readout
until the digit(s) change
to update the time.
The multiplexed drive uses (typically) open collector NPN transistors
connected to the 10 cathodes tied
The time to shift out the bits is not critical, the clock rate is as fast
as you implement it, there is only a minimum clock time, but no maximum one.
Brightness should be the same as putting the tube pin directly to ground,
the internal resistance of the mosfet in the HV5530 is in the Ohms
Thanks.In terms of nixie brightness, is there any advantage in using serial to
parallel converter+shift register vs multiplexing using high voltage
transistors on anodes and cathodes of the nixies? Other than saving component
and uC pins, of course.
Original message From: Bill
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