BI-MODAL VOLTAGE CONVERTER

摘要

A bi-modal voltage converter and associated method for reducing stress on secondary rectifiers and decreasing switching losses. An embodiment of the voltage converter comprises three switches and control circuitry that is operative, upon a determination with respect to the input voltage, to select between a two-switch operation and a three-switch operation. When the input voltage is greater than a threshold value, one of the three switches is permanently turned on, while the other two switches are controlled using a pulse-width modulated (PWM) signal. When the input voltage is equal to or less than the threshold value (e.g., requiring a duty cycle greater than 50%), all three switches are controlled by the PWM signal.

主权项

1. A method of operating a voltage converter having a first switch connected between a first terminal of an input voltage source and a first section of a primary winding of a transformer, a second switch connected between a second section of the primary winding of the transformer and a second terminal of the input voltage source, and a third switch connected between the first section and the second section of the primary winding, the method comprising:
determining if the input voltage is greater than a threshold value; and responsive to determining that the input voltage is greater than the threshold value, turning the third switch ON while controlling the first switch and the second switch using a pulse-width modulated signal.