| 摘要 |
PURPOSE:To reduce power loss and heat by mounting a high resistance body connecting a first conductivity well region, in which an inversion channel is formed on a surface by a gate electrode, and a second conductivity type source region on either of MOS power transistor on the high side or the low side. CONSTITUTION:The P-type well regions and source electrodes S of MOS power transistors 19a, 19b, 19c on the high side are connected through high resistance bodies 120 while the P-type well regions and drain electrodes D of MOS power transistors 19d, 19e, 19f on the low side are short-circuited. Parasitic diodes Ds on the source connecting sides of the MOS power transistors 19d, 19e, 19f on the low side prevent reverse currents from a battery 21. On the other hand, the high resistance bodies 120 inhibit reverse currents through parasitic diodes Dd on the drain connecting sides of the MOS power transistors 19a, 19b, 19c on the high side. Accordingly, source parasitic resistance is lowered, and power loss can be reduced. |
