Single-stage single-switch input-current-shaping technique with fast-output-voltage regulation

A new single-stage single-switch input-current-shaping (S⁴ ICS) technique, which combines the boost-like input-current shaper with a continuous-conduction-mode (CCM) DC/DC output stage, is described. In this technique, the boost inductor can operate in both the discontinuous conduction mode (DCM) and CCM. Due to the ability to keep a relatively low voltage (<450 V_DC) on the energy-storage capacitor, this technique is suitable for the universal line-voltage applications. The voltage on the energy-storage capacitor is kept within the desirable range by the addition of two transformer windings. The principle of operation of the S⁴ICS circuit with a forward DC/DC converter is presented. Experimental results obtained on a 100 W (5 V/20 A) prototype circuit are also given