| 摘要 |
A serially-connected diode pair made of diodes having a high withstand voltage and a low on-resistance is formed based on a high withstand voltage vertical PNP bipolar transistor process technology. Two of the diode pairs are connected in parallel to form a bridge so that there is formed a high-efficiency full-wave rectifier circuit that is free from a leakage current due to a parasitic transistor. The serially-connected diode pair is formed by connecting a diode composed of a P type semiconductor substrate, that makes an anode, and an N type buried layer, that makes a cathode, and a diode composed of a P+ type conductive layer, that makes an anode, and an N type epitaxial layer, that makes a cathode, in series with an electrode AC1. An N+ type buried layer and an N+ type conductive layer are foamed to prevent an electric potential at the N+ type buried layer from becoming lower than an electric potential at a P+ type buried layer even when a large positive voltage is applied to the electrode AC1, so as to prevent a parasitic PNP transistor composed of the P+ type buried layer, the N+ type buried layer and the P type semiconductor substrate, that make an emitter, a base and a collector, respectively, from turning on.
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