🚀 go-pugleaf

In article <1k247hINNsof@shelley.u.washington.edu>, whit@carson.u.washington.edu (John Whitmore) writes:
 In article <1993Jan25.135100.46744@kuhub.cc.ukans.edu> rsl09@kuhub.cc.ukans.edu writes:
 
: >  I am interested in a power amplifier that could drive a DC motor/actuator.
: >I am using the actuator in a slow-response feedback loop. The power amplifier
: >should interface an OP-AMP, that produces the error signal, and the
: >actuator that demands up to 3 Amps for input voltages up to 20 volts.
: >Therefore, I need a push-pull 60 W DC power amplifier. I have been able
: >to find couple of power OP-AMPs that seem to to able to do the job. But,
: >they are expensive - price is around $100. 
: 
: 	And, power op amps can usually NOT handle an inductive load
: (like a motor).  They will burn up (no, internal current limiting
: is NOT a solution here: the problem is reverse-biasing the output
: transistors' emitter junction, and kills the amplifier at LOW current).
: 
: 	If the motor doesn't need to reverse, a PWM switching
: regulator + pass transistor can do a good job.  In the general
: case, you might consider buying a computer-controlled stepping
: motor for the task (but that doesn't interface nicely with
: an op amp feedback circuit...).
: 
: 	John Whitmore

Ah, but consider an Intel 80C196 variety microcontroller.  It can generate the PWM
signals or digitally drive a stepper, and has a built in 10 bit A/D for the
analog feedback.


Chris
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