PURPOSE: To avoid damage with the opposite polarity voltage and to enable integrated circuit constitution, by providing the transistor operated with the production of the high voltage spike voltage of inductive load.

CONSTITUTION: The emitter of Tr 15 is connected to the collector of the transistor Tr 12 driving the coil(inductive load) 14, the base of Tr 15 is connected to the drive power supply Vcc via the resistor 16, and the collector of Tr 15 connected to the base of Tr 12 via Tr 11. Further, when the input of the positive voltage is stopped to the base of Tr 11, Tr 11, 12 are OFF, and a high voltage spike voltage is developed at the both ends of the coil 14, greater in magnitude than the power supply, to turn on Tr 15 and spike voltage is absorbed with Tr 11, 12 turned ON. Further, even if negative surge voltage is present at the power supply line, or the power supply is connected in opposite way, since current flows via the parasitic diode 18, Tr 15 and resistor 16, it is restricted with the resistor 16 and no circuit is damaged.