Abstract: In an electronic switch which includes a pair of terminal portions 14, 14, and self arc-suppressing elements Q21, Q22 having a one-way on and off control construction connected in inverse-series between the pair of terminal portions and which turns on and off the self arc-suppressing elements Q21, Q22 with phase control, shunt resistors R51, R52 provided between the pair of terminal portions 14, 14 and connected in series to the pair of self arc-suppressing elements Q21, Q22 and thyristors S71, S72 for extracting the gate voltages applied to gates of the self arc-suppressing elements Q21, Q22 upon driving are provided. Furthermore, thyristors S71, S72 are driven by the voltages across the shunt resistors R51, R52 generated when overcurrent larger than predetermined current flows through the shunt resistors R51, R52.

Abstract: In a phase controller used in a light control of an incandescent lamp, noise reduction, prevention of elements from damage due to short circuit current, downsizing and lower cost are purposed. A CPU circuit of a control circuit sets a gradual increase term during which a load voltage applied to the incandescent lamp is gradually increased by driving a self-quenching type switching device such as an IGBT. After passing the gradual increase term, a main switching device such as a TRIAC is turned on. The phase controller further comprises a current sensor such as a shunt resistor for sensing a value of the load current flowing through the self-quenching type switching device, according to need. The CPU circuit compares the sensed value of the load current with at least one reference value, and selects driving manner of the main switching device and the self-quenching type switching device corresponding to the result of comparison.

Abstract: To provide an electronic switch capable of instantly releasing overcurrent from flowing between a pair of terminal portions. In an electronic switch which comprises a pair of terminal portions 14, 14 ad self arc-suppressing elements Q21, Q22 having a one-way on and off control construction connected in inverse-series between, the pair of terminal portions and which turns on and off the self arc-suppressing elements Q21, Q22 with phase control, shunt resistors R51, R52 provided between the pair of terminal portions 14, 14 and connected in series to the pair of self arc-suppressing elements Q21, Q22 and thyristors S71, S72 for extracting the gate voltages applied to gates of the self arc-suppressing elements Q21, Q22 upon driving are provided. Furthermore, thyristors S71, S72 are driven by means of the voltages across the shunt resistors R51, R52 generated when overcurrent larger than predetermined current flows through the shunt resistors R51, R52.

Abstract: In a phase controller used in a light control of an incandescent lamp, noise reduction, prevention of elements from damage due to short circuit current, downsizing and lower cost are purposed. A CPU circuit of a control circuit sets a gradual increase term during which a load voltage applied to the incandescent lamp is gradually increased by driving a self-quenching type switching device such as an IGBT. After passing the gradual increase term, a main switching device such as a TRIAC is turned on. The phase controller further comprises a current sensor such as a shunt resistor for sensing a value of the load current flowing through the self-quenching type switching device, according to need. The CPU circuit compares the sensed value of the load current with at least one reference value, and selects driving manner of the main switching device and the self-quenching type switching device corresponding to the result of comparison.