| 摘要 |
PURPOSE:To save electric power by using two semiconductor light emitting elements and a photocoupler connecting photodetectors consisting of diodes opposed to said elements between the gate and source of an FET in parallel. CONSTITUTION:An LED8 is opposed to a photocell group 10, and an LED7 is opposed to a photocell group 9 and a photodiode 12 which are optically insulated from the LED8 and photocell group 10. In case of using an n channel type MOS FET11 when the titled switch is to be turned on, the LED8 is turned on to generate photoelectromotive force in the photocell group 10 and positively charge the gate capacity of the MOSFET11. Since the charge of the gate capacity is not almost reduced even if the LED8 is turned off and electromotive force disappears from the photocell group 10, the switch can be driven by a pulse-like signal. When a switch is to be turned off, the LED7 is turned on to generate electromotive force in the photocell 9 and simultaneously connect the photodiode 12, so that the gate capacity is discharged. By said configuration it is unnecessary to continue to turn on the LED8. |
