Patent ID: 9178434
Filing Date: 2015-11-03
Classification: H02M

Abstract:
1. A DC-to-DC converter, comprising: a power transformer having a primary side and a secondary side; a plurality of power transistors coupled to the primary side of the transformer; a secondary bias supply coupled to the secondary side of the transformer; and a secondary side controller coupled to the secondary side of the transformer and configured to generate a feedback control signal based on a voltage level associated with the secondary side of the transformer; further comprising an integrated transistor driver and pulse width modulation (PWM) controller that receives an input voltage of the DC-to-DC converter, and wherein, during startup, the secondary side controller receives operating power from the integrated transistor driver and PWM controller controlling the plurality of power transistors, but after startup, the secondary side controller instead receives operating power derived from an output voltage from the secondary side of the transformer; wherein the integrated transistor driver and PWM controller includes: a pulse generator that generates pulse signals to be used during startup to control the plurality of power transistors; and a plurality of switches, each switch selects either one of the pulse signals from the pulse generator or a gate drive control signal from the secondary side controller to control one of the power transistors; further comprising a PWM detect unit to detect a presence of the gate drive control signal from the secondary side controller and to cause the switches to be controlled on the basis of whether the gate drive control signal is detected; and wherein the PWM detect unit disables the pulse generator when detecting a presence of the gate drive control signal from the secondary side controller.