| 摘要 |
PROBLEM TO BE SOLVED: To provide the load drive circuit of a high side form where deterioration in performance and destruction of a MOS transistor(TR) are surely prevented. SOLUTION: The circuit that is provided with an N-channel MOS TR 1 whose drain connects to a point of a power supply voltage VD and whose source connects to a load L at a terminal opposite to a ground level terminal and with a charge pump circuit 2 that boosts the power supply voltage VD and provides an output of the boosted voltage. A control circuit 3 gives an output voltage VO of the charge pump circuit 2 to a gate of the TR 1 to make the TR 1 conductive and to supply a current to the load L, has a clamp circuit 5 consisting of Zener diodes ZD1, ZD2 connected in series whose anode connects to a line of the power supply voltage VO and whose cathode connects to an output terminal 2a between the output terminal 2a of the charge pump circuit 2 and the line of the power supply voltage VD. As a result application of a voltage higher than the breakdown voltage between a gate and a drain of the TR 1 is surely prevented. |
