Part Number:DRV10983
I am working on a custom designed board using the DRV10983, with an external MCU running a PI speed control loop. The motor speed is being read via I2C, run through the PI loop and the Speed Control register is updated to keep the motor speed consistent. The motor was tuned according to TI documentation and appears to be running properly. Using a Tek scope with a current probe, my peak current through a motor phase is 1.49A (peak, not RMS). While tuning my speed control loop, I have found that the DRV10983 is consistently tripping the Lock0 fault. My original setting for the HWiLimitThr register was 0x06 which should equal 2.8A. When discovering this, I increased the HWiLimitThr to 0x07 which should equal 3.2A. Much to my confusion, I found that I was actually tripping the Lock0 fault at a lower peak current threshold during operation. After finding this, I decreased the HWiLimitThr to 0x05 which should equal 2.4A, and with this lower threshold, I now see longer operation at my peak operating current than with higher HWiLimitThr values. I am still seeing Lock0 faults which is a problem, so I need some help in figuring out why I am seeing lower thresholds for higher HWiLimitThr values. Especially considering I am now where near the current trip values on my scope measurements. I was able to capture the trip point where the Lock0 fault occurred with HWiLimitThr = 0x07 and the DRV10983 was tripping when less than 1A was going through the motor phases.
Any help would be greatly appreciated,
Mark