Power Integrations, Inc.
High side signal interface in a power converter

Abstract:

A controller for use in a power converter of a motor drive includes a control circuit configured to turn ON a high side switch by sinking a current of an ON signal. A high side signal interface circuit is coupled to receive the ON signal to generate a drive signal to control switching of the high side switch in a presence of a common mode signal caused by slewing at a half bridge node. The high side signal interface circuit includes a common mode cancellation circuit coupled to provide a common rejection signal to provide a cancellation or rejection of the common mode signal. A first current hysteresis comparator is coupled to receive a common mode rejection signal, a first current signal, and a fourth current signal, and generate a first output signal in a presence of a common mode voltage.