BJT driver with dynamic adjustment of storage time versus input line voltage variations

摘要

A power converter controller includes a storage time reference circuit to generate a storage time reference signal in response to an input voltage signal. A first comparator generates a collector off signal in response to a current sense signal of a BJT and a collector off reference threshold signal. A storage time regulator circuit generates a base off reference threshold signal in response to the storage time reference signal and the collector off signal. A second comparator generates a base off signal in response to the current sense signal and a base off reference threshold signal. A driver circuit controls switching of the BJT in response to an output voltage signal, discontinues charging a base terminal of the BJT in response to the base off signal, and starts discharging the base terminal of the BJT in response to the collector off signal during a switching cycle of the BJT.