| 摘要 |
A multiple output dc to dc converter is described that improves efficiency for auxiliary outputs using a secondary side switch. The converter uses a switching circuit to place an alternating voltage from a dc power source across a transformer. The switching circuit is controlled by a primary PWM controller which regulates the primary output voltage by adjusting the duty cycle of the switching circuit. The switching circuit produces an alternating voltage across the center-tapped winding of the transformer, which is rectified by diodes connected to the winding to create a full-wave output. This output is used by a primary output circuit to create the primary output voltage, and is also used to create an auxiliary output voltage by using a secondary side switch and auxiliary PWM controller to regulate the auxiliary output. A bypass element, which can be a diode, is connected between the transformer and the auxiliary output circuit to bypass the auxiliary switch during one phase of the full wave output cycle, thereby increasing the efficiency of the auxiliary output by eliminating losses due to the switch during that phase. The invention can be used with any common converter topology that uses a full wave type output, including, but not limited to, full-bridge, half-bridge, push-pull, clamped-mode forward converter, or any other topology with a full-wave rectified output.
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