| 摘要 |
PURPOSE:To attain high speed switching by providing a control circuit to charge/discharge a control voltage of a switching element quickly. CONSTITUTION:In applying an input voltage between relay input terminals 1, 2 a light emitting element 3 outputs an optical signal. Photodiode array 4, 5 receive the said optical signal to generate an electric signal, a control terminal voltage of a charging switch element 7 rises and output terminals are made conductive. Then an output switching element 9 is conductive. In this case, a discharge switch element 8 is made conductive. When an optical signal of the element 3 is interrupted, an electric charge of the photodiode array 5 is discharged through a resistor 6, the voltage across the array drops rapidly and the charging switch element 7 is made nonconductive. Thus, the supply of the control voltage from the photodiode array 4 to the power control terminal of the switching element 9 is interrupted. The discharge switch element 8 discharges only the stored electric charge between the control terminals of the element 9 and it is not required to discharge the storage charge of the photodiode array 4 thereby decreasing the discharge time.
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