I am seeing strange spikes on VISEN about 2.5ms apart. Could this be related to Over-current protection? At one part in the datasheet, OCP retry time is specified as 2.5ms. In another part of the datasheet, it says “if the current exceeds the current limit, all MOSFETs in the H-bridge are turned off. After approximately 1ms, the bridge is automatically re-enabled.” Can someone explain this discrepancy?
Is the “current limit” in question the one that is set by the ISET resistor?
Hello,
To answer one of your questions (and transitioning into the other), the ISET resistor controls both the current limit and the VISEN output voltage. Here is what the datasheet has to say about this relationship:
Do you observe the behavior as mentioned by you and described in the datasheet where the IC re-enables in 1ms? What is the current RISET that you have implemented? Do you have any details on the load you are trying to drive?
On another note, the behavior you are seeing could be related to OCP as 2.5ms corresponds to the OCP retry time. However, depending on whether you are able to observe the H-Bridge turn off and reset in 1ms would confirm this. I wonder if increasing the current limit will fix things here assuming you are able to confirm this. Observing other significant waveforms here would certainly narrow things down.
Hope some of what I said provided some insight. But most of all I am looking forward for more clarification with the questions I’d asked.
Best,
Krishan
