designing a pwm circuit

Discussion in 'The Projects Forum' started by larz, Nov 21, 2014.

  1. larz

    Thread Starter New Member

    Nov 18, 2014
    Its a school project, i need to follow the flow chart given

    This is what i have so far

    Any tips, hints or obvious errors in the circuit??
  2. DickCappels


    Aug 21, 2008
    It looks like a well though-out design!

    The output transistors might get hot -maybe better to turn around so their emitters are connected to the supply rails which would allow them to be saturated they could saturate (as well as a Darling can saturate). That might require the use of a couple of transistors to drive them.

    Current limit such as in the circuit below would be a good idea.


    The LM411 is apparently up to the task as far as output current and speed are concerned but its an opamp so you might have to add a little bit of hysteresis to prevent oscillation when switching output polarity.