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From: firstname.lastname@example.org (David)
Subject: Re: Help needed - H-bridge, ClassD output stage IC
Date: 16 Jan 2003 21:39:37 -0800
References: <email@example.com> <firstname.lastname@example.org>
NNTP-Posting-Date: 17 Jan 2003 05:39:37 GMT
Thanks a lot for the STMicroelectronics chip information. It looks a
lot more easier to use than the TI one. However, the only thing they
say about the switching frequency is on page 4 of the datasheet:
Input pulse width = 50% Duty;
Switching Frequency = 384Khz;
No LC filters;
Does this mean that the highest switching frequency is 384khz? The
modulator's highest frequency is at 50% duty obviously, but they are
not explicit saying that this is the fastest switching frequency the
chip can work at.
My modulator is of 7th order with an oversampling ration of 64. This
gives a 2.8Mhz PRF but there is a technique called 'bit-flipping' used
to reduce it without adding too much noise.
email@example.com (Ian Smith) wrote in message news:<firstname.lastname@example.org>...
> Yes you can put your PWM into the TI power stage; but be warned, if
> you don't follow the PWB layout guidelines, the chip could go up in
> smoke. It's a very high speed device.
> TI get pretty good perfomance out of it without feedback.
> If you can get some, the STA500 from STMicroelectronics would be
> easier to use. Zetex do it with discrete FETs, but the board layout is
> a little more difficult.
> What order is your DS modulator, out of interest?
> Good luck!
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