Patent ID: 8068324
Filing Date: 2011-11-29
Classification: H02H

Abstract:
1. A protection circuit, comprising: a capacitive device storing and supplying a first electrical energy; a fusible element connected in series with the capacitive device for constituting a branch circuit; a power factor correction converter including a buck converter, wherein the buck converter provides the first electrical energy to the capacitive device and is coupled to the branch circuit for controlling a charging and a discharging of the capacitive device; and an overvoltage modulation unit connected in parallel with the branch circuit, wherein: the overvoltage modulation unit includes a thyristor having a gate and connected in parallel with the branch circuit, an overvoltage conduction unit, and a voltage-division circuit electrically connected to the thyristor and the overvoltage conduction unit; when the branch circuit begins to have an overvoltage, the overvoltage conduction unit instantaneously conducts for causing the voltage-division circuit supplying a trigger voltage to the gate of the thyristor; and an absolute value of a modulating current flowing through the overvoltage modulation unit is increased instantaneously by a trigger of the trigger voltage, so that a second electrical energy in the first electrical energy instantaneously released from the capacitive device is applied to cut off the fusible element.