H bridge switches

Discussion in 'General Electronics Chat' started by drfreaky, Jul 9, 2009.

  1. drfreaky

    Thread Starter Member

    Jul 5, 2009
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    Can i switch on a H-Bridge using -Ve/+Ve voltages instead of using PWM switches or are they any alternatives to switch on the bridges without using PWM or Microcontrollers?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Well, you really do not need a negative supply to an H-bridge. Ground will do fine.

    If you simply wish to control a motor in direction and not speed, a simple DPDT switch is all you need to do that - no H-bridge at all. Does that satisfy your definition of an H-bridge switch?

    If you are going to the trouble of an H-bridge, then PWM makes sense. Open loop PWM is simple with no microcontroller.
     
  3. drfreaky

    Thread Starter Member

    Jul 5, 2009
    17
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    Well i am trying to control the heating and cooling of TEC using a H-bridge using a PID controller so i would expect the output from the controller can either be negative or positive, Any recommendations?
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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    Perhaps the larger issue is the nature of the control. Is is to be proportional, or setpoint on/off?
     
  5. drfreaky

    Thread Starter Member

    Jul 5, 2009
    17
    0
    Its base on setpoint using a PI controller say if the temperature of the device cooled reaches the setpoint it should have zero error although it is impossible and i am using a thermocouple as its feedback with the AD595 as the thermocuple amplifier, So i was thinking to use a H-Bridge with PWM but i dont know whether it can be controlled in analogue since my circuit is based on analog not digital.
     
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