SEMICONDUCTOR DEVICE AND POWER SUPPLY DEVICE

摘要

A power supply topology is used in which a transistor is provided on the side of an output node of a rectifying circuit. An inductor is provided on the side of a reference node, a resistor is inserted between the transistor and the inductor, and one end of the resistor is coupled to a ground power supply voltage of a PFC circuit. The PFC circuit includes a square circuit which squares a result of multiplication of an input voltage detection signal and feedback information (output voltage of an error amplifier circuit). The PFC circuit drives on the transistor when a detection voltage developed at the resistor reaches zero, and drives off the transistor when the detection signal reaches an output signal of the square circuit.

主权项

1. An LED illuminating device comprising:
a first output node and a second output node coupled with a light emitting diode; a rectifying circuit which rectifies ac power and supplies power to a rectified output node; an N-channel type MOSFET having a gate terminal, a drain terminal and a source terminal, the drain terminal being coupled with the rectified output node; a current detection resistor coupled with the source terminal and a ground node, the ground node being coupled with a ground voltage; an inductor coupled with the ground node and the first output node; a diode whose anode and cathode are coupled with the second output node and the source terminal of the N-channel type MOSFET, respectively; an output capacitor coupled with the first output node and the second output node; and a control circuit coupled with the gate terminal and the source terminal of the N-channel type MOSFET,
a detection voltage of the source terminal being inputted into the control circuit,the control circuit providing a PWM signal to the gate terminal to control the N-channel type MOSFET.