| 摘要 |
A planar-type transistor is formed by selectively diffusing a base layer on a surface of a silicon substrate that will act as a collector layer, and then selectively diffusing an emitter layer on the base layer. In addition, the collector layer on the front surface of the planar-type transistor chip is provided with a current detecting electrode, while the back surface of the silicon substrate is provided with a collector electrode. As the transistor is turned on and current flows through the collector, voltage is induced between the collector electrode and the current detecting electrode according to the collector current because of the resistance of the silicon substrate. Therefore, the transistor can quickly and precisely detect the collector current and transmits the detected current as a current detecting signal from the current detecting electrode to a control IC. A power transistor which surely prevents destruction by a surge and allows for reduction of the transistor chip in size can be offered in this manner. <IMAGE> |
