Fairchild Korea Semiconductor Ltd.

Semiconductor Components Industries, LLC

Gwan-Bon Koo

Jin-Tae Kim

Young-Bae Park

Hang-Seok Choi

Hyun-Chul Eom

Jae-Hwoan Chi

Chen-Hua Chiu

Kwang-Il Lee

Moon-Ho Choi

Hang Seok Choi

Sang-Hyun Lee

Sung-Won Yun

Young Sik Lee

Ju-Hyun Kim

Sang-Cheol Moon

Eui-Soo Kim

Bong-Geun Chung

Shanmei Li

Gyoung-Soo Park

Kyung Oun Jang

Yoo-Woong Hwang

Jinho Choi

Jin-Woo Moon

J Hoon Lee

Won-Seok Lim

An LED driver is provided. The LED driver comprises a plurality of driving units and a fold circuit. The driving units are coupled to an LED string including a plurality of LEDs for driving the LEDs. The fold circuit is coupled to the LED string and divides the LED string into a plurality of LED segments when an input voltage is lower than a threshold voltage. The LED segments are coupled to each other in parallel, and the input voltage is supplied to the LED segments.

LED driver

A method and a circuit of detecting attachment and detachment between a portable device and a power converter are provided. The method and the circuit confirm attachment of the portable device to the power converter and generate an attachment signal. The method and the circuit further detect a bus voltage of the power converter for confirming detachment of the portable device from the power converter.

Method and circuit of detecting attachment and detachment between a portable device and a power converter

A control circuit for LED and an active bleeder thereof are provided. The control circuit comprises an LED driver and the active bleeder. The LED driver drives at least one LED and generates a current-sense signal. The current-sense signal is correlated to an LED current. The active bleeder comprises a bleeder circuit. The bleeder circuit is coupled to the LED driver to receive the current-sense signal and sinks a bleeding current in accordance with the current-sense signal for keeping the current flowing through the dimmer higher than the holding current.

Control circuit for LED and active bleeder thereof

The present invention relates to a piezoelectric circuit, a piezoelectric driving circuit driving the piezoelectric circuit, and a method for driving the piezoelectric circuit. The piezoelectric circuit includes a sub-piezoelectric circuit and an external inductor coupled in parallel with the sub-piezoelectric circuit. The external inductor discharges the sub-piezoelectric circuit when a polarity of a piezoelectric voltage, that is, a both-end voltage of the piezoelectric circuit is inverted. The piezoelectric driving circuit includes first and third switches connected to a first node of the piezoelectric circuit and second and fourth switches connected to a second node of the piezoelectric circuit.

Piezoelectric circuit, piezoelectric driving circuit for the piezoelectric circuit, and piezoelectric driving method

The present invention relates to a switch control circuit that controls a switching operation of a power switch circuit that includes cascode-coupled first and second transistors. A switch control circuit includes a first zener diode coupled between a gate of the first transistor and a first end of a capacitor supplying a power voltage and a second zener diode coupled to a gate and a source of the first transistor, and a first resistor coupled between the first zener diode and the second zener diode.

Switch control circuit and power supply device including the same

A synchronous rectifier network unit and synchronous rectifying method. The synchronous rectifier network unit includes a first body diode to which a first current flows at a first time when the first current flows to a first coil, and a first transistor which is turned on after the first body diode is conducted, and to which the first current flows, and it rectifies the first current by differently controlling the turn-off time of the first transistor according to the first current.

Synchronous rectifier network unit circuit and method

Disclosed are a switch controller, a switch control method, a converter using the same, and a driving method thereof. A first voltage is generated by using a voltage that is input to an input terminal, and a soft start signal is generated by using the first voltage during a soft start duration. A switching operation is controlled by using the soft start signal during the soft start duration.

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

A switched-mode power supply includes a soft-burst circuit to minimize or prevent distracting audible noise. The power supply includes a control circuit for controlling switching of an output transistor to deliver a regulated output voltage to a load. The control circuit adjusts the operating frequency of the power supply based on a control signal. The soft-burst circuit discharges a storage device to minimize or prevent audible noise when the control signal reaches a particular level.

Soft-burst circuit for switched-mode power supplies

The present invention relates to a protection circuit, a resonance converter having the same, and a protection method thereof. A resonance converter having high-side and low-side switches senses a current flowing through the low-side switch and determines a zero voltage switching failure by using a width of a current flowing to a negative direction of the low-side switch.

Protection circuit, resonant converter including the protection circuit, and protecting method of the resonant converter

A switching mode power supply includes a switching transistor, coupled to a primary coil at a primary side of a transformer for converting an input DC voltage, supplying power to a secondary and a tertiary coil at a secondary side of the transformer according to an operation of the switching transistor; a switching controller receiving a feedback voltage corresponding to a first voltage generated in the secondary coil and receiving a detection signal corresponding to a current of the switching transistor to generate a switching control signal for controlling the turn on/off of the switching transistor; and a feedback signal generator receiving the first voltage and the switching control signal to set a sampling period, and storing the first voltage, sampled with a last pulse of the first pulse string within the sampling period as a feedback voltage. The output voltage is thereby accurately detected without opto-couplers or shunt regulators.

Switching mode power supply and driving method

Ripple of an input voltage is used to modulate a switching operation frequency of a switch mode power supply. A sensing voltage corresponding to the input voltage is received, a current ripple that is proportional to a difference between a peak value of the sensing voltage and the sensing voltage is generated, and a modulation control signal that is variable by the current ripple is generated. A switching frequency is modulated using an oscillator signal that is variable by the modulation control signal, and reduces the output voltage ripple.

Frequency modulation controller, switch mode power supply including the same, and switching operation frequency modulation method

A converter is provided including: a first switch; an energy transmitting element for converting input energy into output energy according to the switching of the first switch; and a switching controller for detecting a time when a voltage between a first terminal and a second terminal of the first switch reaches a valley of a resonance waveform, and actuating the first switch corresponding to one of the detected valleys of the resonance waveform. The switching controller includes: a valley detector for changing the state of the output signal whenever a voltage between a first terminal and a second terminal of the first switch reaches a valley of the resonance waveform; and a PWM controller for actuating the first switch corresponding to an output signal of the valley detector.

Converter that actuates a switch corresponding to a detected valley of a resonance waveform

The present invention relates to a converter and a driving method thereof. The converter includes a switch controller that controls switching operation of a master switch and a slave switch. The switch controller detects a center point of one switching operation period of the master switch by using an internal triangular wave having a period that is the same as that of the one switching operation period, and starts the switching operation of the slave switch at the detected point. The internal triangular wave signal has a waveform that varies within one period, and detects a crossing point of an average value of the internal triangular wave and the internal triangular wave as a center point of one switching operation period of the master switch.

Converter and driving method thereof

The present invention relates to a frequency modulation device and a switching mode power supply using the frequency modulation device. To prevent electro-magnetic interference (EMI), it is required to slightly vary a switching operation frequency in an SMPS operation. In some embodiments, at least one first signal having a predetermined cycle is generated, a second signal corresponding to a level of a first signal is generated at a turn-off time of a switch, a first reference voltage having at least two different levels is generated according to the second signal, and an oscillator signal for increasing along a first slope during a first period and decreasing along a second slope during a second period between the first reference voltage and a second reference voltage having a level that is different from the first reference voltage is generated.

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Bucheon, South Korea

Gwan-Bon Koo