Fairchild Korea Semiconductor Ltd.

Moon-Sang Jung

Jong-Tae Hwang

Dae-Ho Kim

Jin-sung Kim

Dong-Hwan Kim

Sung-Yun Park

Min-Ho Jung

The present invention relates to a power factor correction circuit and a method of driving the power factor correction circuit. The power factor correction circuit according to the present invention includes a power transfer element configured to receive an input voltage, an input current corresponding to the input voltage flowing through the power transfer element, and a switch connected to the power transfer element and configured to control an output voltage generated by the current flowing through the power transfer element. The power factor correction circuit is configured to detect a zero voltage edge timing of the input voltage by detecting the input voltage, generate a reference clock signal having a frequency that varies according to the detected edge timing, generate a reference signal using the reference clock signal, generate an error amplification signal based on a difference between the output voltage and a predetermined error reference signal, generate the amplification reference signal by multiplying the reference signal by the error amplification signal, and control a switching operation of the switch using the amplification reference signal and a detection signal corresponding to a current flowing through the switch.

Power factor correction circuit and method of driving the same

Disclosed are a switch controller, a switch control method, and a converter based thereon. The switch controller generates an input sensing voltage corresponding to the input voltage of the converter, and compares the input sensing voltage with a predetermined first reference value. The switch controller generates a zero cross detection signal with a first level or a second level depending upon the comparison result, and generates a reference clock signal varying in frequency in accordance with one cycle of the zero cross detection signal. The switch controller generates digital signals by using the reference clock signal and the zero cross detection signal. The digital signals synchronize with the zero cross detection signal, and increase in accordance with the reference clock signal during a half of one cycle of the zero cross detection signal, while decreasing in accordance with the reference clock signal during the other half cycle of the zero cross detection signal. The switch controller generates a reference signal with a voltage level corresponding to the digital signal.

Switch controller, switch control method, and converter using the same

A resonant inverter includes a first driver and a second driver for driving a first and second switching devices, respectively, a dead time generator for generating a first drive signal and a second drive signal respectively, a current-controlled oscillator for supplying, to the dead time generator, an output clock having a frequency determined based on a first current input to the current-controlled oscillator, and a current mirror for supplying the first current to the current-controlled oscillator in an amount proportional to a second current flowing through an external resistor. The current mirror includes a track/hold circuit, to supply the second current in an amount equal to an amount of the second current supplied before a variation in the amount of the second current, during a transition of an output signal between the first and second switching devices.

Resonant inverter exhibiting depressed duty variation

An RC oscillator integrated circuit includes: an active current mirror connected to an external resistor, for receiving a current signal corresponding to a voltage signal applied to the external resistor, performing 1/N-times division of the received current signal according to an input clock signal, and generating a 1/N-times current signal; an oscillation circuit for generating an output voltage corresponding to a charging- or discharging-operation of a capacitor via a current path formed by the active current mirror; a feedback switching circuit for controlling a charging- or discharging-path of the capacitor by a feedback of an output signal Vo of the oscillation circuit; and a divider for generating not only a first clock signal capable of driving the active current mirror according to the output signal of the oscillation circuit, but also a second output clock signal having a compensated mismatch of the active current mirror.

RC oscillator integrated circuit including capacitor

A ballast integrated circuit (IC) for driving a first switching element and a second switching element includes: a variable gain amplifier (VGA) connected to a first input terminal connected to a resistor, for generating an output current signal according to a resistance value of the resistor and a gain control signal; a preheating/ignition controller connected to a second input terminal connected to a capacitor, for generating an output current signal and an output voltage signal acting as the gain control signal according to a voltage of the second input terminal; an active zero-voltage controller for generating a hard-switching current signal and an active zero-voltage switching current signal, such that it adjusts the voltage of the second input terminal according to switching states of the first switching element and the second switching element; an oscillator for generating an oscillation signal upon receiving the output current signal from the variable gain amplifier (VGA); and a dead-time controller for receiving the voltage signal of the second input terminal and an output signal of the oscillator, adjusting a dead time using the received signals, and at the same time generating driving signals of the first and second switching elements.

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Seoul, South Korea

Moon-Sang Jung