Single-stage AC-DC power converter with flyback PFC and selectable dual output current

摘要

A single-stage AC-DC power converter for powering a load at a substantially constant current, and related methods and systems. The AC-DC power converter includes a high power factor correction (PFC) circuit configured in a flyback topology and operating in transition mode. The flyback PFC circuit outputs a direct current (DC) voltage and a DC current. The PFC circuit further includes a flyback transformer and a switch circuit that selectably toggles the substantially constant output current provided to the load between a first and a second, preset constant current. The secondary windings of the flyback transformer are split into two sections, and the switch circuit toggles the two sections of the secondary windings between a series and a parallel configuration to provide the first and second, preset constant currents. The switch circuit includes a switch and three, fast Schottky diodes.

主权项

1. A single stage AC-DC power converter for powering a load at a substantially constant current, comprising:
a high power factor correction (PFC) circuit configured in a flyback topology operating in transition mode; wherein the flyback PFC circuit is connected to an alternating current (AC) power supply and configured to output a direct current (DC) voltage and a DC current; and wherein the flyback PFC circuit further comprises a flyback transformer and a switch circuit that selectably toggles the substantially constant output current provided to the load wherein when the switch circuit is closed, the constant output current is equal to a first, preset constant current, and when the switch circuit is open the constant output current is equal to a second, preset constant current which is equal to twice the first preset constant current, and wherein the DC voltage output is greater when the switch circuit is closed than when the switch circuit is open.