SWITCHED MODE POWER SUPPLY WITH VOLTAGE REGULATOR

摘要

A power supply and method for reliable turn-on of a switched mode power supply (SMPS) in which the same transformer is used for providing power from the primary side to both the main output of the SMPS and a secondary side voltage regulator a train of voltage pulses are transmitted, from the primary side to the secondary side. The voltage regulator generates a feedback signal indicating when it has turned on and is operating, and the transmission of pulses within the train is controlled based on the detection of feedback signal. In this way, only the required amount of power to switch on the voltage regulator is transferred to the secondary side during a start-up operation and excess power at the main output is prevented, thereby avoiding distortion of the desired start-up ramp figure.