My reason in questioning is due to the fact that the 74141 draws ~20ma.
That is quite a bit of current, especially in a non-multiplexed design,
if power usage is a concern. Perhaps there is a reason that you
specifically need a single package solution.
-Adam
On 11/23/2011 1:16 PM, chuck richards wrote:
Ahh, ok then...it appears that the answer to my previous
question is that there is *not* any modern low current
single-package 16-pin DIP equivalent to the old 7441 or 74141
or the russian versions of these.
That being the case, even though the old 7441/74141 draw
a bit of current, they remain the simplest, one-package
solution.
Am I wrong here? Am I missing something?
Chuck
---- Original Message ----
From: [email protected]
To: [email protected]
Subject: Re: [neonixie-l] Yet more 7441, 74141 questions
Date: Wed, 23 Nov 2011 12:39:07 -0800
Here's a link to a reply from David Forbes on this subject:
http://groups.google.com/group/neonixie-l/msg/6195ec3c9b90f2ee
-Adam
On 11/23/2011 12:33 PM, Adam Jacobs wrote:
This is a question that gets asked& answered on this list
occasionally. I think that the simplest/easiest answer is to use
an
array of high voltage drivers on a BCD->Decimal IC. Turns into a
ton
of transistors if you are not multiplexing, though. Mike Moorrees
has
some much more elegant and interesting ideas in old posts on this
subject. Also, Supertex has a whole line of modern HV driver
chips,
some members of the list have spent time looking into their
suitability.
One nice thing to remember is that the extinguishing voltage on a
nixie is usually less than 50v (hence the zeners in the 74141).
Once
the nixie is sunk by ~50v, the nixie turns off - so the driver IC
doesn't have to actually since 180v.
-Adam
On 11/23/2011 12:27 PM, chuck richards wrote:
It's a clock that I designed from scratch.
Basically, it was an exercise in using (6) 74LS160
synchronous counters. It gets the HHMM set via a bank
of (4) thumbwheel switches, and the SS gets zeroed out
and clock stopped via another spring-return toggle switch.
It worked so well that I later decided to make it into a
low current version in order to be as easy on the backup
battery as possible. So, I used all HC and HCT parts.
I used 7441 drivers because that is what I have around here.
I am not aware that any low-current versions of those
drivers were ever manufactured.
Indeed, *is* there any modern low-current bcd-to-decimal
high voltage ic that provides a one-package 16 pin DIP
solution to this requirement? Is there? Please let me
know if there is.
I am now making up another similar clock, but using 8422 tubes
instead of 6844A kind. Just thought if I could power down
the 7441/74141 ics when running on backup battery, that would
save the bulk of about 60 mA.
What low current drivers would you suggest?
Thanks again for all of your help!
You guys are a great bunch! -Chuck
---- Original Message ----
From: [email protected]
To: [email protected]
Subject: RE: [POSSIBLE SPAM] Re: [neonixie-l] Yet more 7441,
74141
questions
Date: Mon, 21 Nov 2011 13:03:23 -0800
Is this a clock that was already built and you have been
modifying
for
lower current use? or is this a clock that you designed from
the
ground-up for low current? If it is the latter, I can't help
wondering
why there are 74141's in there at _all_. :)
-Adam
On 11/21/2011 10:03 AM, chuck richards wrote:
In an effort to build a low-current nixie clock,
I tried using all 74HC parts. That works great,
but there are still the (6) 7441, or 74141 TTL drivers.
How about this idea? When the clock is running on
the backup battery with no line power, what if 5 volts
Vcc were to be removed from the 7441/74141 drivers?
That way, the clock itself would keep time, and the current
draw on the battery would be kept as low as possible since
only the CMOS ics would be running.
Question: If the ground is kept on the 7441/74141 ics
and the Vcc lead is disconnected, will that cause any
problems for the 74HC160 counters that have their bcd outputs
feeding the 7441/74141 bcd inputs?
In other words, I am concerned about the possibility of
the 7441/74141 having some path that would try to
draw excessive current from the inputs when Vcc is
disconnected.
Is this a good idea to try, or is it a recipe for
trashing some HC160 counters?
Thanks. Chuck
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