JAJSBF8B June 2011 – April 2018 TPS54478
PRODUCTION DATA.
The TPS54478 features monotonic startup into pre-biased output. The low side FET turns on for a very short time period every cycle before the output voltage reaches the pre-biased voltage. This ensures the boot cap has enough charge to turn on the top FET when the output voltage reaches the pre-biased voltage. The TPS54478 also implements low side current protection by detecting the voltage over the low side MOSFET. When the converter sinks current through its low side FET is more than 3.1 A, the control circuit will turn the low side FET off. Due to the implemented prebias function, the low side Fet reverse current protection should not be reached, but it provides another layer of protection in the undesired events such as oscillation induced by load.