Analysis, Design and Development of Single Switch Forward Buck AC-DC Converter for Low Power Battery Charging Application

In this paper a low power single switch high power factor AC-DC converter is designed and developed for battery charging. Desired features for battery charger are low cost, fast charging, high power factor, high efficiency, minimum ripple and high reliability are fully achieved using proposed circuit. The converter using single switch forward buck converter topology and operating in discontinuous conduction mode (DCM) is designed and developed to achieve inherent power-factor correction in voltage follower mode. The design equations are derived and calculations are performed to achieve circuit parameters. The test results on developed converter are compared with simulated results to validate proposed design. A prototype for 20.25 W battery charger is built and tested to verify the design and analytical model. Satisfactory performance is obtained from experimental results.