Patent ID: 7759914
Filing Date: 2010-07-20
Classification: H02M,Y02B

Abstract:
1. A power converter, comprising: an energy transfer element coupled between a power converter input and first and second power converter outputs; a switch having a first terminal coupled to the energy transfer element to provide a conduction path for the energy transfer element to receive an input current supplied from the power converter input; a control circuit coupled to the switch to control switching of the switch to generate a first output voltage at the first power converter output and a second output voltage at the second power converter output, wherein a sum of the first and the second output voltages is regulated in response to a first voltage reference, wherein the second output voltage is regulated in response to a second voltage reference, wherein a current in the energy transfer element is coupled to be increased when a voltage across the energy transfer element is a difference between an input voltage at the power converter input and the first output voltage, and wherein the current in the energy transfer element is coupled to be decreased when the voltage across the energy transfer element is the sum of the first and second output voltages; a capacitor having a second terminal and a third terminal, wherein the second terminal is coupled to the first terminal of the switch and the third terminal is coupled between the first power converter output and a feedback terminal of the control circuit, wherein the capacitor is coupled to charge to a voltage approximately equal to the sum of the first and second output voltages, wherein the control circuit is further coupled to regulate the sum of the first and second output voltages in response to a signal proportional to the voltage on the capacitor; and a shunt circuit coupled across the first power converter output to regulate the second output voltage in response to the second voltage reference.