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Original question:

DRV120: No peak in output, strait to PWM

DRV120: DRV120 - Failed Driver

Jawaad Ali1
Prodigy 20 points
Part Number: DRV120

I recently had a DRV120 show a fault condition.

I measured the OUT pin to ground and measured 18.5kOhm for the failed part.

On a working circuit I usually measure OUT to ground around 2.4MOhm.

We have an application where the valve can be left on for 24 hours or more.

Is this supported by the DRV120?

  • 0
    TI__Intellectual 1965 points

    Hi Jawaad,

    Thanks for your question. Let me contact the expert who supports this part. You can expect a response by 1/24/20.

    Best,

    Grant

  • 0
    TI__Expert 4940 points

    Hi Jawaad,

    Seems to me a blown up output FET due to high power, that's something wrong with the valve or supply voltage.

    How long the valve is on should make no difference.

    Regards,

    Costin

  • 0 in reply to Costin Cazana
    Prodigy 20 points

    Thank you for the reply Costin.  I have included a screenshot of the schematic for the driver.  

    We have made slight modifications.  We now have the RPEAK = 182k  and TKEEP = 2.2uF.  So the peak current is roughly 91.5mA.  We are using a 24V power supply. The valve we are driving is the LVM095R-5C-6-Q.

  • 0 in reply to Jawaad Ali1
    TI__Expert 4940 points

    Hi Jawaad,

    I see nothing wrong, external components are for typical application. Selected peak and hold current are average type can not damage the internal FET.

    I couldn't found the valve inductance and resistance, hard to estimate valve current ripple without.

    The inductance and resistance will affect the ripple and voltage headroom.

    My suggestion is to measure valve current and DRV120 OUT voltage, to check first if these are the expected one.

    If so how long valve is used can not damage DRV120. Maybe the valve got shorted or something similar.

    Regards,

    Costin