Overvoltage protection circuit and method thereof

摘要

The overvoltage protection circuit in accordance with the present invention includes a resistor divider, a reference voltage supply unit, a comparator, and an inverter, wherein the inverter consists of a series-parallel combination circuit of first to third semiconductor switching elements which are driven by receiving an output of the comparator and the first semiconductor switching element and the second semiconductor switching element or the third semiconductor switching element are driven by receiving the output of the comparator, output an external voltage when the external voltage is within the range of the voltage required for an internal circuit, and flow the external voltage to a ground and thus make the voltage supplied to the internal circuit 0(zero)V to protect the internal circuit from an external overvoltage when the external voltage is a voltage (overvoltage) higher than the required voltage for the internal circuit.

主权项

1. An overvoltage protection circuit comprising:
a resistor divider consisting of a plurality of resistors, receiving a voltage from an external power supply, dropping the received voltage, dividing the dropped voltage into the voltages having a relatively smaller size than a power voltage, and providing the divided voltage; a reference voltage supply unit for supplying a preset reference voltage having a certain size; a comparator for receiving and comparing the voltage divided and provided by the resistor divider and the reference voltage supplied from the reference voltage supply unit and outputting a low or high signal according to the result of the comparison; and an inverter for receiving the output signal (low or high) of the comparator and outputting a signal (high or low) apposite to the output signal of the comparator, wherein the inverter comprises: a first semiconductor switching element having one side electrode terminal connected to the external power supply and driven, by receiving the output of the comparator; a second semiconductor switching element connected to the first semiconductor switching element in series and driven by receiving the output of the comparator; and a third semiconductor switching element provided between the first semiconductor switching element and the second semiconductor switching element to be connected to the first semiconductor switching element in parallel to the second semiconductor switching element and driven by receiving the output of the comparator, wherein the first semiconductor switching element and the second semiconductor switching element or the third semiconductor switching element are driven by receiving the output of the comparator, output the external voltage when the external voltage is within the range of the voltage required for an internal circuit, and flow the external voltage to a ground and thus make the voltage supplied to the internal circuit 0(zero)V to protect the internal circuit from an external overvoltage when the external voltage is a voltage (overvoltage) higher than the required voltage for the internal circuit; wherein the external voltage is within the range of the voltage required for the internal circuit, the second semiconductor switching element and the third semiconductor switching element are turned off with turning on the first semiconductor switching element, and wherein the external voltage is the voltage (overvoltage) higher than the voltage required for the internal circuit, the second semiconductor switching element and the third semiconductor switching element are turned on without turning of the first semiconductor switching element.