Power supply having a surge protection circuit

摘要

A power supply having a power protection circuit has a rectification circuit and a converter. An input terminal of the rectification circuit is connected with the AC mains. A first voltage dependent resistor is connected with the AC mains. The converter has a transformer. A primary side of the transformer is connected with an output terminal of the rectification circuit, and the secondary side is connected to a power output terminal and a ground terminal. A Y capacitor is connected between the primary side of the transformer and the ground terminal. A surge protection module is connected between the first voltage dependent resistor and the Y capacitor. When a surge occurs between the primary and secondary sides of the transformer, a surge current is shunted by the surge protection module to the ground terminal through the Y capacitor without damaging internal components or circuits inside the power supply.

主权项

1. A power supply having a surge protection circuit, comprising:
a rectification circuit having:
an input terminal connected with an AC power input; wherein the AC power input has a live line and a neutral line; andan output terminal adapted to connect to a load connected to the ground; a first voltage dependent resistor connected across the live line and the neutral line of the AC power input; a converter having:
a transformer having:
a primary side connected to the output terminal of the rectification circuit; anda secondary side generating an induced voltage; a power output terminal connected with the secondary side of the transformer and a ground terminal and adapted to connect to a load; a Y capacitor connected between the primary side of the transformer and the power output terminal; and a surge protection module having a second voltage dependent resistor having two ends, wherein one end of the second voltage dependent resistor is connected to the first voltage dependent resistor, and the Y capacitor is connected between the other end of the second voltage dependent resistor and the ground terminal; wherein when a surge occurs between the AC power input and the power output terminal, a surge voltage arising from the surge is clamped by the first voltage dependant resistor, and a surge current arising from the surge is shunted to sequentially flow through the surge protection module and the Y capacitor to the ground terminal with energy of the surge current absorbed by the surge protection module and the Y capacitor.