7.3.23 Overcurrent Protection

Both low-side overcurrent and high-side short-circuit protection are implemented. The low-side overcurrent fault and warning thresholds are programmed via PMBus. The low-side MOSFET average current is compared to the set fault threshold. High-side pulses are terminated on a cycle-by-cycle basis whenever the current through the high-side MOSFET exceeds the fixed short circuit threshold.

When either a low-side overcurrent or high-side short-circuit threshold is exceeded in a switching cycle, a counter is incremented. If no overcurrent condition is detected in a switching cycle, the counter is decremented. When the counter counts to three, an overcurrent fault condition is declared, and the output shuts down and restarts after 7 × TON_RISE time or is latched off until re-enabled, or ignored depending on the fault response setting. The behavior of the power stage during the various fault scenarios is shown in Table 7.