| 摘要 |
PURPOSE:To prevent fluctuation of a turn-on voltage and the increase of transmission delay time by providing a series connection circuit comprising a forward connection diode and a current limiting resistor between power supplies. CONSTITUTION:Power terminals VDD, VSS, an input terminal I and an output terminal O are connected to an internal circuit C and diodes D1-D4 are connected between the input terminal I and the outpout terminal O in opposite polarity. Moreover, a power supply Zener diode ZD5 whose reverse turn-on voltage is neawrly 10V and a series circuit comprising a forward diode D6 and a current limit resistor R are connected between the power terminals VDD, VSS. Thus, an overvoltage applied between the input terminal I and the output terminal O is clamped nearly at a maximum of 10.8V even when the circuit is compatible with live line insertion/removal. Then the increase in the fluctuation of the turn-on voltage and the transmission delay time is avoided due to the application of an overvoltage of nearly 20V and generation of hot carrier. |
