Fairchild Korea Semiconductor Ltd.

Semiconductor Components Industries, LLC

Ji-Hoon Jang

Won-Tae Lee

Hyeong Seok Baek

Hang-Seok Choi

Young-Je Lee

Gye-Hyun Cho

Moon-Ho Choi

Jae-Yong Lee

Jae-yong Lee

Yoon-Woong Chung

A resonant converter includes a first switch on a primary side and a second switch coupled to the first switch, a first synchronous rectification switch on a secondary side conducted according to a switching operation of the first switch, a second synchronous rectification switch on the secondary side conducted according to a switching operation of the second switch, and a switch control circuit configured to detect a waveform of one end voltage of at least one of the first synchronous rectification switch and the second synchronous rectification switch, determine one of a below region and an above region, and differently control conduction duration of the first and second synchronous rectification switches according to a determined result.

Resonant converter and driving method thereof

The power supply device includes a power switch including one terminal to which an input voltage is transferred; an inductor including one terminal connected to another terminal of the power switch; a diode connected between a ground and a floating ground; a sensing resistor connected between the floating ground and the one terminal of the inductor. A switch controller compares a modulation sensing voltage depending on a sensing voltage generated from the sensing resistor with a high peak reference and a low peak reference when a LED string is connected between an inductor and the ground. The switch controller controls a switching operation of a power switch according to the comparison result. The high peak reference and the low peak reference are references for controlling an upper limit and a lower limit of an LED current flowing through the LED string, respectively.

Switch controller, power supply device comprising the same, and driving method of the power supply device

A resonant converter includes a first switch on the primary side and a second switch coupled to the first switch, a synchronization rectification switch on a secondary side configured to conduct during a conduction period in response to a switching operation of the first switch, and a switch control circuit configured to determine an operating region of the resonant converter to be below resonance based on a result of a comparison between the conduction period and an on period of the first switch.

A protection mode control circuit includes an auto-restart counter configured to count the cycle of a first signal in a protection condition and to generate an auto-restart signal when a result of the count reaches a protection reference value and a latch mode unit configured to generate a latch mode signal for changing protection mode to latch mode when the auto-restart signal is consecutively generated by a predetermined threshold number.

Protection mode control circuit, switch control circuit including the protection mode control circuit and power supply device including the switch control circuit

A modulation mode control circuit includes a modulation mode controller configured to select modulation mode based on the result of a comparison between a control voltage and a predetermined PWM threshold voltage and to generate a PWM reference voltage using the PWM threshold voltage and the control voltage and a control signal generation unit configured to generate a first control signal based on the result of a comparison between an oscillation control signal for controlling a switching frequency and the control voltage and the result of a comparison between the oscillation control signal and the PWM threshold voltage and to generate a second control signal based on the result of a comparison between the oscillation control signal and the PWM reference voltage.

Modulation mode control circuit, switch control circuit including the modulation mode control circuit and power supply device including the switch control circuit

A resonant converter includes a first switch coupled between a first node and a primary side ground, a second switch coupled between an input voltage and the first node, at least one capacitor and at least one inductor coupled in series between both ends of the first switch, and a switch control circuit that shifts switching frequencies of the first and second switches during a period for which an abnormal event lasts when occurrence of the abnormal event is detected, and shifts the switching frequencies in an opposite direction when the abnormal event ends.

Switch control circuit and resonant converter including the same

A resonant converter includes a primary-side winding electrically coupled to an input voltage, a secondary-side winding electrically coupled to a load, first and second switches coupled to one end of the primary-side winding, and a switch control circuit configured to differently control switching frequency limit ratios of the first and second switches by differently limiting a frequency variation ratio of a first clock signal that determines switching frequencies of the first and second switches according to variation of one of the input voltage and the load.

Provided are a switch control device, a switch control method, and a power supply device. The present invention generates power voltage required to operate the switch control device by using full-wave current rectification voltage generated by rectifying an AC input and detects a zero cross-point when a full-wave rectification voltage is zero voltage by using the edge of power voltage. The present invention generates a reference signal synchronized to the full-wave rectification voltage by using the detected zero cross-point and controls a switching operation of a power switch by comparing a reference signal with current which flows on the power switch.

Switch control device with zero-cross point estimation by edge detection, power supply device comprising the same, and switch control method with zero-cross point estimation by edge detection

The present invention relates to a switch controller, a switch control method, and a power supply including the switch controller. An exemplary embodiment of the present invention detects an on-time of a power switch of the power supply and decreases a frequency of a clock signal according to a period during which the detected on-time is shorter than or equal to the minimum on-time. According to the exemplary embodiment, switching of the power switch is controlled according to a clock signal, and the minimum on-time is an on period of the power switch that cannot be shortened.

Growing community of inventors

Incheon, South Korea

Ji-Hoon Jang