To provide a low-loss rectifying circuit having a control function for dispensing with dead time control for preventing the backflow of current to a voltage conversion circuit from a capacitor connected to a load in parallel when it is used for a switching supply, and preventing a through-current in a flywheel FET and a diode.
The rectifying circuit comprises a first current path in which a transistor Q1 is driven by a constant-current element CS1, a second current path in which a transistor Q2 is driven where an emitter and a base are short-circuited by a constant-current element CS2, a rectifying current path intermittently controlled by the FET1, and a transistor Q5 bypassing the transistor Q1. When the FET1 is energized, the base of the transistor Q5 is driven, and the transistor Q5 is turned on, thus turning on the first current path, driving the gate of the FET1, turning off the FET1, and interrupting the rectifying current path when positive potential is applied to the drain of the FET1 and the collector of the transistor Q2, and negative potential is applied to the source of the FET1.
TAKAKUSA HIDEHIRO
OKADA MINORU
WADA HARUKI
Takashi Matsumoto
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