| 摘要 |
SMPS system of the present invention comprises rectifier (F) for rectifying AC voltage received from a line input (S); capacitor (C1), which is connected to output of the rectifier (F) for filtering rectified voltage; transformer (T), which is receiving filtered voltage from a first winding via at least one switching means (M3, M4) and which outputs output voltage (V O1 , V O2 , V On ) from second winding; first switching means (M1), which is in series to said capacitor (C1) and which limits the voltage of said capacitor (C1); first resistor (R1) which is connected between the return of the first winding of transformer (T) and rectifier (F); controller (C) which receives first feedback signal from output voltage (V O1 , V O2 , V On ) through first feedback line (F1), receives second feedback signal from first resistor (R1) through second feedback line (F2), controls the operation of the switching means (M3, M4) connected to input of the transformer (T), and generates a reference voltage according to second feedback signal; comparator (P) which compares said reference voltage with a second reference voltage, which depends on the output of the rectifier (F), and generates a threshold voltage according to comparison result; second switching means (M2) which performs "not" operation to said threshold voltage and controls the operation of the first switching means (M1). |
