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From: beringt@ncc1701.eng.McMaster.CA (Tom Bering)
Subject: Re: PWM speed controllers
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Date: Fri, 25 Mar 1994 18:15:42 GMT
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Michael Thompson EE (michael@jupiter.sun.csd.unb.ca) wrote:
: Has anyone used the Motorola 34060 pulse width modulation chip to 
: make a bidirectional electronic speed control for a dc motor? I've 
: used it to switch MOSFETS and thus control speed in one direction 
: but don't know how to use a PWM i.c. to provide bidirectional control.
: Could I use two of them to get two outputs to drive an H-bridge?

Not Yet.  You need to switch the sign of the feedback loop, and
to redirect the signals going into the H-Bridge.  I researched
all of the servo control chips I could find a while ago.  The
important variable for all of them was the power level you were
operating at.  If you were in the required voltage/current range,
many of the chips would work.  If you were outside that range, you
needed a chip like the LM638/639 which is a general purpose design.
The important variable is what are you trying to do ?

: Has anyone use the Motorola servo chip for the above purpose? I know I can 
: use an 8031 and its timers provide PWM signals to an H-bridge but don't
: want to use a microcontroller just for a speed control. Oops, I forgot 
: to mention that I want to use the output of a R/C receiver for the control 
: signals for the PWM circuit.

: Finally, does anyone know of a PC based C compiler that produces INTEL
: hex code that could be downloaded into an EPROM? For the Microprocessor 
: Design course the students write their monitor program for their 8088
: boards in asssembler but we'd like to do it in C instead. 

Both MS VisualC++ or C with the expanded DOS kit and MASM, and BorlandC++
with TASM will perform the tricks you are after.  You will need a binary
to INTEL HEX convertor utility, but this is usually provided with EPROM
programmers.

From

Tom Bering
beringt@ncc1701.eng.McMaster.CA

: Thanks for your help!
: -----------------------------------------------------------------------
: Michael G. Thompson
: Electrical Engineering Dept.
: University of New Brunswick
: Fredericton, New Brunswick
: Canada  E3B 5A3

: mgt@unb.ca

: "Even the dead love a parade..."
: -----------------------------------------------------------------------
