| 摘要 |
The switch mode power supply is supplied from the AC mains and produces a DC output. The circuit has a rectifier bridge (BR) at its input, with two output terminals, one positive (X) and the other negative (Y). A winding (W1) is connected across these terminals through a series switch (S1). A branch formed of a capacitor (C) and a diode (D1) is also connected across the terminals. The diode is connected to prevent charging of the capacitor from the positive supply. An auxiliary winding (W4) is connected between the negative terminal and, through a diode (D2) and series impedance (Z), to the junction between the capacitor and the first diode. The diode is connected to allow charging of the capacitor from the auxiliary winding. |
