JPH0348690B

PURPOSE:To make an output terminal into the floating state, by making a current supply path to a drive switching element different from a current supply path to a push switching element driven with the drive switching element. CONSTITUTION:A terminal 8 is opened or grounded and a terminal 4 is opened to give up the function of the push MOSTQu1 and the drive MOSTQu2. Thus, only a circuit part 50 surrounded in dotted lines is operated. In this case, a current flowing to the arrow B from a terminal 2 is first blocked at a diode D2 and is not grounded at all. This current flows to a diode D4 in the forward direction to the terminal 4, but since the terminal 4 is opened, the current does to flow to this path. Thus, the current flowing to a circuit unit from the terminal 2 reaches a drain of an MOSTQd via a diode D3, and when the MOSTQd is in off-state, the said current does not flow to anywhere and the floating state of the terminal 2 is ensured.