Abstract: A method, power converter and controller are disclosed for controlling a power converter having a main converter connected between a first input voltage and a ground and having a main output at an output terminal, an auxiliary converter connected between a second input voltage and the ground and having an auxiliary output, an output capacitor connected between the main output terminal and a ground, and an auxiliary capacitor connected between the auxiliary output and the main output terminal; and a controller; the method comprising: operating the main converter at a first frequency, operating the auxiliary converter at a second frequency; controlling the main converter to control the voltage at the auxiliary output; and controlling the auxiliary converter to control the voltage at the main output.

Abstract: Disclosed are a controller and power converter having a main buck converter connected between a first input voltage and ground and having a main output, a bidirectional auxiliary converter connected between a second terminal and ground and having an auxiliary output connected to the main output, an output capacitor, and an auxiliary capacitor connected between the second terminal and the ground for providing a second terminal voltage at the second terminal; the controller comprising: first control circuit configured to operate the main converter at a first frequency; and second control circuit configured to operate the auxiliary converter at a higher frequency; the first control circuit being further configured to operate the main converter in dependence on the second terminal voltage; and the second control circuit being further configured to operate the auxiliary converter to control the voltage at the main output terminal.