Patent attributes
A switching circuit of the present invention can be advantageously used in an electronic control unit mounted on an automotive vehicle. The switching circuit is constituted by a pair of P-channel MOS-FETs connected in series between an input terminal and an output terminal. Sources of both MOS-FETs are connected to a common source junction and gates thereof are connected to a common gate junction. A Zener diode connected between the common source junction and the common gate junction is used for protecting the MOS-FETs. A resistor is connected in parallel to the Zener diode to bring the switching circuit to a non-conductive state when the gate voltage at the common gate junction becomes indefinite and a high voltage is supplied to the output terminal. In place of the resistor, an additional P-channel MOS-FET may be used in the switching circuit to bring the switching circuit to the non-conductive state when the voltage at the common gate junction becomes indefinite.
