While testing the ITRIP condition in DRV8245, independent mode.
Here, we have used 0.9ohm load resistor,16V with 100% duty cycle.
The output current waveform should TRIP at 12.6A( IPROPI resistance=1Kohm and ITRIP resistance=22.1Kohm) , means output current max should be 12.6A , but here it is reaching to 17A((load current at 16V,0.9ohm)) which is above the ITRIP current.
Waveforms are attached for your reference.
Is our understanding on ITRIP is correct?
Hi Pratik,
The ITRIP current regulation mechanism is designed primarily with a BDC motor which typically has coil inductance such that the load is L and R in serires vs. a pure resistive load such as the load resistor used in your test. When a resistive load is used the load current rises at a faster rate and usually exceeds the ITRIP level during the current regulation blanking time. ITRIP regulation kicks in as soon as the blanking time expires. Having a series inductor will reduce the load di/dt and mitigate this situation. With a BDC motor's self inductance it works fine. This is why in your tests with a resistive load the current exceeded the set threshold.
Regards, Murugavel
