2 Analysis of Common OC Issues and Solutions

When encountering OCP (overcurrent protection) issues in an application, the first step is to verify whether the test method is accurate. The overcurrent detection mechanism of the amplifier operates by sensing the current flowing through the MOSFETs in the half-bridge output stage. Therefore, it is recommended to preferentially use an oscilloscope current probe to measure the current along the path from the SW pin to the inductor. A common test method is to lift the pin at the end of the inductor closest to the chip and perform the current measurement at that point. This is because the current waveform at this test point most accurately reflects the actual current condition inside the chip, making the measurement results more reliable.

For capturing the current at the moment OCP is triggered, there are generally two approaches: one is to use the signal on the chip's FAULT pin as the oscilloscope trigger source; the other is to set the oscilloscope to Roll mode and locate the abnormal moment by capturing the current peak. After completing the correct hardware measurements described above, if it can be confirmed that the cause of the FAULT is indeed OCP triggering and that the hardware behavior is consistent with the register error report, it is then necessary to further investigate the root cause of the excessive current from both the software configuration and hardware design perspectives.