precision amplifier circuit

Discussion in 'The Projects Forum' started by thiam, Aug 26, 2009.

  1. thiam

    Thread Starter New Member

    Aug 18, 2009
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    0
    Hi,
    i need a guideline to construct a precision amplifier circuit to a motor driver(OPA 541). my input voltage is from -5V to 5V whic from PIC18F4331. Anyone can help me?? pls reply thanks.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    I moved your post here, as it seemed more hardware related.

    The OPA541 is an op amp with high current capability. Is it capable of driving your motor?

    Can you say what the precision amplifier between it and the microprocessor is to do? Especially as to the parameters which must be precisely controlled/reproduced.
     
  3. thiam

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    the dc motor model is M586TE. its rated current 4A and voltage 24V. in your opinion, OPA 541 suitable as motor driver for it?
    As i know, the output current from for microcontroller is not constant. thus, precision amplifier to maintain that current.
    Do you have any recommendation precision amplifier and circuit for me?

     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    282
    Several questions come to mind. What do you mean by
    If the output from whatever unidentified source is not "constant", how does the addition of an amplifier correct the situation?

    It would be most helpful if you could say what the motor control is to do. What output from the mocroprocessor is to control the motor. Will the controller run the motor at a constant speed, vary the speed, and/or reverse the motor direction?
     
  5. thiam

    Thread Starter New Member

    Aug 18, 2009
    4
    0
    Now i using pic18F4331 to interface the dc motor to computer by using cascade pid controller to control its speed, direction, and torque. The motor driver used is OPA 541.
    However, i have been told that the current from pic18F4331 is not constant. As a result, i need to design a precision amplifier to maintain the current. Do you have any suggestion for me??
    In your opinion, should i use OPA 541 as my motor driver if i use PIC18F4331 as decoder??
     
    Last edited: Aug 29, 2009
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    I suppose the 18F4331 is the PID controller, and the D to A output is the drive signal output to the OPA541. A low pass filter will serve to smooth the steps out of the D to A is that is what you mean by "the current is not constant".
     
  7. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    1,015
    69
    I don't think the chip has a D to A, though it does have PWM outputs.

    Possibly the idea is to filter the PWM output to a DC level and offset it to suit the bipolar amp input.
     
  8. Perfectboy

    New Member

    Sep 9, 2009
    9
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    I agree. your problem is not so clear to us to solve it.
    [​IMG]
     
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