Single soft switched isolated converter with constant output current for light emitting diode driver

In this study, a single switch soft-switching isolated converter for light emitting diode (LED) driver applications is introduced. In the proposed converter, the transformer parasitic elements are employed as resonant elements to transfer energy and to attain soft-switching condition. The converter constant output current only depends on the input voltage, resonant capacitor, switching frequency and transformer turns ratio. Thus, the converter does not require any current feedback to regulate the LED current. In addition, the adjustment of light emission can be simply accomplished which results in cost reduction and system simplicity. Experimental results are presented to justify the validity of theoretical analysis.