DC Voltage from rectangle impulse

Discussion in 'The Projects Forum' started by gofeto, Aug 6, 2012.

  1. gofeto

    Thread Starter New Member

    Aug 6, 2012
    Hey guys, I am new here and i need your help. I need to make circuit that converts one 5 volt TTL impulse (50% duty cycle) into DC Voltage, but the voltage needs to depend on the frequency of the TTL impulse, that means when i lower the frequency, the voltage should lower too, or something like that, i want to ask you is it a good idea to use LM2907 or something alike it, and should i put also a low-pass filter after the LM2907? Any help would be appreciated.
    Thanks in advance
    ps The pulse comes from Pulse generator.
  2. mcasale

    Active Member

    Jul 18, 2011
    What sort of load will the output drive? If it's small enough, all you need is an RC filter.

    What sort of "ripple" can you tolerate?
  3. #12


    Nov 30, 2010
    mcasale is talking about a simple frequency to voltage circuit. They work, but can work very badly at low frequencies. So...whatcha want for the low end frequency?
  4. gofeto

    Thread Starter New Member

    Aug 6, 2012
    output is a laser with current at about 100ma ill be working at relatevly high frequencies at about 10khz to 100 khz.