SLUSBO6C JANUARY 2014 – October 2018 TPS40425
PRODUCTION DATA.
The overcurrent protection uses a two-tier approach. Cycle-by-cycle current limit is implemented when the inductor peak current exceeds the set threshold. PMBus sets the current limit using the IOUT_OC_FAULT_LIMIT and IOUT_OC_WARN_LIMIT commands. After a series of three OC counts, the device turns off both high-side and low-side MOSFETs and enters hiccup mode by default. Only cycle-by-cycle current limit is applied if OC is detected during soft-start operation.
The IOUT_OC_FAULT_RESPONSE PMBus command programs the response to an OC fault. The controller can be programmed to either shut down until power-cycle, CNTLx toggling, or to shut down and attempt restart after a delay of 7 × tON_RISE. When channel 2 is configured as a slave, this command cannot be programmed. In such a case where channel 2 is a slave, the fault response setting for channel 1 is automatically applied to channel 2. For 3-phase and 4-phase configurations, both the controllers must be programmed for the appropriate fault response.