Patent ID: 8929103
Filing Date: 2015-01-06
Classification: H01F,H02M,Y02B

Abstract:
1. A switch-mode power converter for converting an input voltage from an input source to an output voltage for supply to a load coupled to converter load terminals, the power converter comprising: a power isolation transformer further comprising a magnetic core having a center leg and outer legs, one or more primary windings and one or more secondary windings of the power transformer being wound on the center leg; a primary converter circuit comprising one or more primary controllable power switches effective to supply the input voltage to one or more primary windings of the power isolation transformer; a secondary converter circuit fully isolated from the primary converter circuit and comprising one or more secondary switches being individually switchable and further coupled between the one or more secondary windings and the load terminals; a primary switch control circuit effective to control conduction of one or more primary controllable power switches; a secondary switch control circuit effective to control conduction of the one or more secondary switches; a control circuit effective to control operation of the primary switch control circuit and the secondary switch control circuit based at least in part on a feedback signal; a drive transformer comprising at least first and second drive transformer windings wound on an outer leg of the magnetic core, the drive transformer windings configured to provide power for controlling the primary and secondary switches, the drive transformer windings further configured to provide isolation between the primary and secondary control circuits; the voltage across primary windings having voltage waveforms of similar shape as the drive voltage of the controllable power switches except during turn-on and turn-off transitions; and the windings of the drive transformer tightly coupled with each other on the outer leg, and further loosely coupled with the windings of the power transformer, wherein different voltage waveforms are provided in the windings of the drive transformer and windings of power transformer for a short period of time sufficient to initiate turn-on or turn-off of the controllable switches coupled to the power transformer.