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DRV110: DRV110 - Keep time increase during warm up

Michel Waleczek
Prodigy 10 points
Part Number: DRV110

Tool/software:

Hello,

I use a DRV110 for driving a solenoid, with a peak current of 5A and a hold current of 2A. The currents measured are correct, but I have an issue with the keep time. When the part is cold, at room temperature, the keep time is much lower than expected, and the time increases after one or two minutes of use and stabilizes. I have noticed that the keep current is much larger when the part is cold.

Is this a known issue ? I changed several times the DRV110 itself and more or less all parts without success.

Thank you for your help because I am stuck with this issue.

Schematic diagram:

PRB735E20_24VDC1 Ind b.pdf

Results of measurements:

mesures_27062024A.pdf

  • 0
    TI__Mastermind 23411 points

    Hey Michael, apologies for the delay. Thank you for the well organized PDF! 

    Can you monitor the voltage at C5?  Such a large capacitor might take a long time to charge up depending on the supply current and this could be contributing to the effect. Maybe also try the tests with letting the circuit sit powered on for a minute or two before turning on the DRV110 to see if that affects it. 

    One thought is to look into the capacitor derating over temperature, since the keep time is directly based on the cKEEP capacitor and the time it takes for the voltage to reach 100mV.  For aluminum electrolytic caps the capacitance increases as temperature increases, by up to 40% across temperature range according to my google research.  This wouldn't explain going from 150ms to 600ms though, and doesn't work if the keep capacitor is still the same temperature as it started which is likely the case if only the DRV110 is warming up. 

    Do you have a thermal camera that you can use to monitor the device temperature for each hold time? 

    Is the solenoid warming up as well over these tests?  

    Best,

    Jacob