Patent ID: 8320092
Filing Date: 2012-11-27
Classification: H02H

Abstract:
1. A protection circuit comprising a normally non-conducting protection circuit main body and a voltage application section, wherein: the protection circuit main body comprises a first terminal, a second terminal and a control terminal; in the protection circuit main body, a first voltage line is connected to the first terminal for applying a first voltage to a protected circuit, and a second voltage line is connected to the second terminal for applying a second voltage to the protected circuit; the protection circuit main body makes a state between the first terminal and the second terminal conductive when a magnitude of a voltage applied to the control terminal is a predetermined threshold value or greater; the voltage application section comprises a wiring line with a first end connected to the first voltage line and a second end connected to the control terminal; when a first current having predetermined frequency characteristics flows from the first end in a particular flow path of the wiring line, the voltage application section applies a voltage of less than the threshold value to the control terminal due to generating an induced current so as to generated a magnetic field to cancel out a magnetic field occurring due to the first current, the induced current impeding flow of the first current; when a second current not having the frequency characteristics flows from the first end in the particular flow path, the voltage application section applies a voltage of the threshold value or greater to the control terminal.