Re: [CAD_CAM_EDM_DRO] L297/L298 board concern

Do you have fast diodes in a bridge? Slow diodes have long reverse recovery
time during which transistors in L298 are short connected to a power source.
This can be source of overheating. Beside this, I'm think that 20kHz and 2A
is much for L298.

Igor

----- Original Message -----
From: "Dan Mauch" <dmauch@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, November 15, 2002 3:47 PM
Subject: RE: [CAD_CAM_EDM_DRO] L297/L298 board concern


> Another problem could be that you don't have the chopper circuit working
> correctly, I have seen some circuits that put a cap on the sense lines
> and the value is such that it supressses the chopper. Then again you
> have the sync frequency set wrong. The r/c circuit should use a 3300 pf
> cap and a 22K resistor which will give you about 20KHz chopping
> frequency.
> Dan
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