To provide a power supply reverse connection protective circuit which can recognize the reverse connection of an external DC power supply and the application of a negative surge and can surely prevent the generation of an overcurrent in an electronic control device.
The power supply reverse connection protective circuit includes a rectifier 12 connected to a low electrical potential side terminal 3 and a high electrical potential side terminal 2 of an external DC power supply. A high electrical potential side node 13 and a low electrical potential side node 14 of the rectifier 12 are connected to a reverse connection protection control circuit 11. Even when the polarity of the external DC power supply is reversed, the rectifier 12 generates a high electrical potential at the high electrical potential side node 13 and a low electrical potential at the low electrical potential side node 14. Accordingly, a comparator 15 of the reverse connection protection control circuit 11 determines whether the external DC power supply is reversely connected to a power supply terminal 3 and a ground terminal 5, and a reverse connection protective element drive circuit 16 surely turns off a reverse connection protective element 10. As a result, an overcurrent from the ground terminal 5 to the power supply terminal 3 is surely prevented.
Hiroshi Takeuchi
Takahisa Shimada
Yuji Takeuchi
Katsumi Imae
Kazunari Ninomiya
Tomoo Harada
Iseki Katsumori
Seki Kei
Yasuya Sugiura
Daisuke Kawabe
Masanori Hasegawa
Tsuguya Iwashita
Koji Fukumoto
Ryo Maeda
Mawaki Hachizo
Yukichi Matsunaga
Kenji Kawakita
Shohei Okazawa