Patent ID: 8222872
Filing Date: 2012-07-17
Classification: H02M

Abstract:
1. A switched-power circuit, comprising: a magnetic coupling element for coupling an input of the switched-power circuit to an output of the switched-power circuit and having a primary winding and at least one auxiliary winding; a switching circuit for controlling charging of the magnetic coupling element from an input voltage source connected to the input of the switched-power circuit to the primary winding of the magnetic coupling element; a control circuit coupled to the switching circuit for generating control signals for operating the switching circuit in response to a feedback signal provided from the output of the switched-power circuit; and an auxiliary power supply having a selectable operating mode that is selected responsive to at least one control signal having at least two discrete states for selecting between at least two corresponding operating modes, wherein the auxiliary power supply has an auxiliary power supply input coupled to the auxiliary winding of the magnetic coupling element, wherein the auxiliary power supply generates an output voltage from the auxiliary winding in the at least two corresponding output modes such that a first non-zero ratio of the output voltage generated in a first one of the operating modes from the auxiliary winding to a voltage available from the auxiliary winding is greater than a second non-zero ratio of the output voltage generated in a second one of the operating modes from the auxiliary winding to the voltage available from the auxiliary winding.