Drive circuit for light emitting diode array based on a buck-boost topology

摘要

Features of the invention are related to drive circuits that provide both power factor correction and voltage conversion in a single circuit and in some implementations drive an LED array. This single stage converter uses a buck-boost topology and can operate LED arrays that have DC voltages above or below the AC line voltage. An output side filter and bulk energy storage device is placed at the output of the circuit. Bulk energy storage can be provided by an inductor, a capacitor, or a combination of an inductor and a capacitor. The output side filtering can be provided by a capacitor or a capacitor and an inductor. The circuit also includes a switch and a switch control device for controlling the switch to provide power factor correction.

主权项

1. A drive circuit, comprising:
a first load connection point and a second load connection point for connecting a load to an output of the drive circuit; an output side filter and bulk energy storage device, wherein a first connection point of the output side filter and bulk energy storage device is connected to the first load connection point, a second connection point of the output side filter and bulk energy storage device is connected to the second load connection point, and a third connection point of the output side filter and bulk energy storage device is connected to a cathode of a free wheeling diode; a first inductor connected to an anode of the free wheeling diode and a switch and to the first load connection point and the first connection point of the output side filter and bulk energy storage device; the free wheeling diode, wherein the cathode of the free wheeling diode is connected to the third connection point of the output side filter and bulk energy storage device and the anode of the free wheeling diode is connected to the first inductor and the switch; the switch connected to the anode of the free wheeling diode and the first inductor and to a first drive circuit input; and a control device for controlling the switch to provide power factor correction, wherein the drive circuit provides both power factor correction and load regulation using the switch, wherein the drive circuit is operable for direct connection to an output of a bridge rectifier, wherein the first drive circuit input connects a first output terminal of the bridge rectifier to the switch and a second drive circuit input connects a second output terminal of the bridge rectifier to the first load connection point, the first connection point of the output side filter and bulk energy storage device, and the first inductor, wherein the output side filter and energy storage device includes a second inductor and a capacitor, wherein the second inductor is connected to the second load connection point and to the cathode of the free wheeling diode and the capacitor, and the capacitor is connected to the first load connection point and the first inductor and to the second inductor and the cathode of the free wheeling diode, and wherein the capacitor and/or the second inductor provide bulk energy storage by storing energy from one power line cycle to a next power line cycle and both the capacitor and the second inductor provide output side filtering.