Power converter controller with multiple power sources

摘要

A controller includes a bypass terminal, a first power circuit, a second power circuit, and a charging control circuit. The bypass terminal is to be coupled to a bypass capacitor coupled to a secondary side of an isolated power converter. The first power circuit is coupled to the bypass terminal and a first terminal to be coupled to a first node of the secondary side. The first power circuit transfers charge from the first terminal to the bypass terminal for storage on the bypass capacitor. The second power circuit is coupled to the bypass terminal and a second terminal to be coupled to a second node of the secondary side. The second power circuit transfers charge from the second terminal to the bypass terminal for storage on the bypass capacitor. The charging control circuit controls which of the first and second power circuits transfers charge to the bypass terminal.

主权项

1. A controller for use in an isolated power converter having an energy transfer element for transferring energy between a primary side and a secondary side of the power converter, the controller comprising:
a bypass terminal to be coupled to a bypass capacitor included in and coupled to the secondary side of the isolated power converter; a first power circuit coupled between the bypass terminal and a first terminal, wherein the first terminal is to be coupled to receive charge from a secondary winding of the energy transfer element on the secondary side, and wherein the first power circuit is coupled between the bypass terminal and the first terminal to transfer the charge from the first terminal to the bypass terminal for storage on the bypass capacitor; a second power circuit coupled between the bypass terminal and a second terminal, wherein the second terminal is to be coupled to receive charge from an output of the power converter on the secondary side, and wherein the second power circuit is coupled between the bypass terminal and the second terminal to transfer the charge from the second terminal to the bypass terminal for storage on the bypass capacitor; and a charging control circuit coupled to control which of the first and second power circuits transfers charge to the bypass terminal in response to at least one of a bypass voltage developed at the bypass terminal and a voltage at the second terminal.