Patent ID: 7283344
Filing Date: 2007-10-16
Classification: H03K

Abstract:
1. An electronic switch, which has a self arc-suppressing element connected between a pair of terminal portions to which AC current is applied trough a load, and which turns on or turn off the self arc-suppressing element with a phase control signal, the electronic switch comprising: overcurrent detection means for detecting whether current flowing between the pair of terminal portions reaches overcurrent larger than predetermined current; and overcurrent protection means for extracting the phase control signal to a control terminal of the self arc-suppressing element, when the overcurrent detection means detects that the overcurrent has been reached, wherein as the self arc-suppressing element, a pair of self arc-suppressing elements having a one-way on and off control construction are connected an inverse-series between the pair of terminal portions, wherein the electronic switch further comprises a resistor as the overcurrent detection means which is provided between the pair of terminal portions and is connected in series to the pair of self arc-suppressing elements, and a switching element as the overcurrent protection means for extracting control voltages applied to the control terminals of the self arc-suppressing elements upon driving, wherein the switching element is driving with a voltage across the resistor generated when the overcurrent larger than the predetermined current flows through the resistor, and wherein first and second shunt resistors are the resistor are connected in series between first and second arc-suppressing elements as the pair of self arc suppressing elements, and first and second switching elements as the switching element are connected in series between the control terminals of the first and second self arc-suppressing elements, wherein a connection point of the first and second shunt resistors and a connection point of the first and second switching elements are connected each other, the control terminal of the first switching element is connected to a connection point of the first self arc-suppressing element and the first shunt resistor, and the control terminal of the second switching element is connected to a connection point of the second self arc-suppressing element and the second shunt resistor, and wherein the first and second switching elements are driven with the voltages across the first and second shunt resistors generated when the overcurrent flows through the first and second shunt resistors.