From: Terry Pinnell
Subject: Re: zero-power toggle circuit; was, how to master electronics
Date: Wed, 20 Nov 2002 20:09:46 +0000
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NNTP-Posting-Date: Wed, 20 Nov 2002 20:10:01 +0000 (UTC)
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Winfield Hill wrote:
>> I spent more time, but didn't get much further with several of the
>> MOSFET types. Then I discovered the main cause. I received a message
>> from a professional CM user, Ron Berthiaume, who subscribes to a CM
>> mailing list I use. Turns out CM has screwed up some of the MOSFET
>> classifications, and as luck would have it, IRF9513 was one of them.
>> I'm not confident of summarising it accurately, so I've pasted most of
>> Ron's analysis here:
>> 1) The IRF9513 FET doesn't work in circuit. (Circuitmaker Problem) I
>> can't find an IRF9513 datasheet but, based on simulation, the device
>> appears to be a depletion mode FET not an enhancement mode FET. ...
> I'm not sure what part Ron is referring to, but the IRF9513 is a 60V,
> 1.6-ohm version of the 9510, and years ago it was listed by IR on the
> same data sheet. It appears to have been discontinued for some time.
> Of course that doesn't mean CM may not have mistakes in its model.
> You can test models through some simple tests, such as Vgs Id current
> sweeps, etc. These are easily done by connecting the gate to drain
> and measuring that Vgs(on) voltage while sweeping the current.
> You could also try CM's IRF9510 model. The 9520 9530 and 9540 are
> progressively larger FETs in the same family. Do you only have a
> limited number of models?
I'm pleased to say I've made better progress. Reducing R4 to 10k may
have helped, I'm not sure. But one thing that definitely did was a
change of simulation technique; I decided to try ramping up the power
supply instead of applying it instantaneously. Some types still fail,
but the situation is no longer confused by some coming ON at PU.
Final results at
Hobbyist, West Sussex, UK