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24 Vdc PWM signals to 5 Vdc for data acquisition

Jerry Kozlowski
Prodigy 10 points

Need buffer for high channel count data acquisition system in which the PMW output of a automotive device is to be monitored for timing.

The output of the device can be 9 to 30 Vdc PWM output and must be captured by a counter/timer at 5 Vdc 

  • 0
    TI__Guru**** 165236 points
    Jerry,

    I see VOH is 9V to 30V, what is the level of VOL? It VOL proportional to VOH?
    What is the impedance of these inputs, meaning can a voltage divider be used directly on the inputs?
    What is the clock rate.

    You could use a low pass filter to convert PWM to DC then use a ADC to read the values.
  • 0 in reply to Ron Michallick
    Genius 3295 points

    Hi,

    Unless I'm missing something, this is a level translator job. I've included three different ways to accomplish this in the attached document. "pwm" in the circuit is a 30V pulse train. The bottom diode (IN5817) can be left out; as shown it would clamp not only the positive going pulse but also any pulses trying to go negative (as may happen when working with automotive stuff). 

    Mike T.

    translators.pdf