Alt-BEAM Archive
Message #05547
To: beam@sgiblab.sgi.com
From: Sean Rigter rigter@cafe.net
Date: Fri, 06 Aug 1999 15:19:06 -0700
Subject: [alt-beam] Re: Low power oscillator
Hi Ben,
There are many solutions and you'll have to provide a bit more
information to pick the most suitable one. One obvious solution is to
lower the Vdd of the oscillator chip (only) by inserting a series ~7V
zener diode. This dramatically reduces the curent consumption but the
voltage swing is limited to Vbat-7V. A transistor with 1M base and
collector resistors can restore the output voltage swing to 12V.
Alternately, the previously posted 74HC4053 voltage doubler circuit can
easily be adapted provide lowpower and full 12V swing. A micropower CMOS
OPAMP can do the 12V oscillator with 100uA in an 8 pin package. Finally
a universal "power smart" design solution could be designed (my
preference) by adding one or two extra components. The latter may be the
solution for reducing power in a variety of "high voltage" CMOS
oscillator circuits.
So we like to know a bit more about your application but at the very
least: the "end of life" battery voltage, output voltage requirements,
frequency stability, available space, and your access to purchasing new
parts.
enjoy
wilf
Ben Hitchcock wrote:
> Although not strictly BEAM, I am putting this question to the list in the
> hope that someone here can help me...
>
> I'm doing a project for university where I need a small, low power
> oscillator. The oscillator must have an on-time of about 0.2 seconds, and
> an off time of 5 seconds.
>
> I would like standby power consumption of less than say 0.1 mA.
>
> The voltage used is 12 volts (I can't change that). At the moment, I have
> tried a couple of designs of oscillator, using a 74C14 chip but the best
> power consumption I get is about 3 or 4 milliamps - way too high for the
> poor little 12 volt battery.
>
> The whole circuit is going to fit inside one of those 'car alarm
> transmitters' which use a 12 volt battery which is about half the size of a
> AAA battery. The whole thing fits very easily into a pocket, or onto a
> keychain.
>
> Any help would be greatly appreciated.
>
> Thanks,
> Ben Hitchcock
5548 Fri, 6 Aug 1999 22:41:44 -0500 [alt-beam] links "beam" "jclark76" I was play...researching on the inter net and I found some neat links
http://www.cs.umn.edu/Research/airvl/pbmin.html
"PBMin is a Pole Balancing Mini-robot. It utilizes a 36 node neural network
that learns to balance a pole. The pole is attached to a variable resistor
to sense pole angle and two infrared sensors to measure cart position." from
the page. there are also links to the abstract and the full paper. I think
zoz brought this up a little while ago.
http://perso.wanadoo.fr/alain.michel/anglais.htm
has freeware schematic and PCB programs for windows. This does pop-up every
once in a while. It seems fairly versatle. I haven't used it yet.
He also has other programs but most are in french. not a problem if you
speak it.
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