REDUCING POWER IN A POWER CONVERTER WHEN IN A STANDBY MODE

摘要

Power converters typically have unique circuitry for graceful start-up and to develop correct operating voltage biases. Typically this unique circuitry is incorporated into a primary-side “start-up” controller. This start-up controller can also be the primary means of control of the power converter once started. However, a secondary-side controller is typically needed for more exact output voltage regulation, duplicating circuitry already present in the primary-side start-up controller. During light-load or no load conditions, on and off switching of the gate driver is stopped when the secondary-side controller sends a standby code inhibit (disable) command to the start-up controller. When power needs to be sent to the secondary side of the transformer to charge a secondary side capacitor, the secondary-side controller sends an enable code command to the start-up controller where it is detect to allow the start-up controller to operate in a normal fashion with the secondary side controller.

主权项

1. A method for reducing standby power in a power converter, said method comprising the steps of:
providing a primary-side start-up controller and a secondary-side controller in a power converter; controlling a power switch coupled to a transformer in the power converter with the start-up controller until a secondary-side voltage from the transformer reaches a desired value then controlling the power switch by sending a pulse width modulation (PWM) signal from the secondary-side controller to the start-up controller; sending a disable signal from the secondary-side controller to the start-up controller to inhibit operation of the power switch and enter into a standby mode; and sending an enable signal from the secondary-side controller to the start-up controller to enable operation of the power switch and return to an operating mode.