Fairchild Korea Semiconductor Ltd.

Silicon Mitus, Inc.

Kyung-Goo Lee

Dong-Hee Kim

Dong-Hun Lee

Sang-Hwa Jung

Jung-Won Kim

Hong-Gyu Han

Seok-Mun Choi

Dong-Hoon Lee

A control device and an LED light emitting device using the same are provided and technology of providing a high contrast ratio to the LED light emitting device and allowing the LED light emitting device to perform a stable operation is disclosed. The LED light emitting device includes a DC/DC converter reference voltage generator that generates a DC/DC converter reference voltage so that a minimum level of a channel voltage having a largest LED voltage drop agrees with a predetermined minimum reference voltage by detecting a plurality of channel voltages corresponding to LED voltage drops of each of a plurality of LED channels LED and an output voltage controller that controls an output voltage of the DC/DC converter using a distribution voltage corresponding to an output voltage and the DC/DC converter reference voltage.

Reference voltage generating device, control device including the reference voltage generating device, and LED light emitting device using the control device

An LED light emitting device and a method of driving the same are provided, and technology that can uniformly sustain the magnitude of a channel current flowing to a plurality of LED channels is disclosed. The LED light emitting device includes: a plurality of LED channels that are formed with a plurality of LED elements that are continuously connected in series; and a constant current source that controls each channel current flowing to the plurality of LED channels according to a predetermined channel reference current to be a predetermined setting channel current, wherein the constant current source includes a plurality of operating amplifiers that control the magnitude of each of the channel currents, and a feedback voltage generating according to a predetermined offset reference current is input to a second input terminal of an operating amplifier for an offset setting period that sets an offset voltage of the plurality of operating amplifiers, a reference voltage generating according to a channel reference current is input to a first input terminal of the operating amplifier, and an offset voltage of each of the plurality of operating amplifiers is set so that an actual channel current may be identical to a predetermined setting channel current.

LED light emitting device and method of driving the same

A mixed type frequency compensating circuit is disclosed. The mixed type frequency compensating circuit includes an integral component sub-circuit of a voltage-amplifier-type frequency compensating circuit and a proportional component sub-circuit of a transconductance-amplifier-type frequency compensating circuit. The integral component sub-circuit amplifies an input voltage signal in a voltage mode. The proportional component sub-circuit amplifies the input voltage signal in a current mode. Accordingly, the mixed type frequency compensating circuit may occupy a small area in a semiconductor integrated circuit.

Mixed type frequency compensating circuit and control circuit

The present invention relates to a converter and a driving method thereof. The converter uses an input voltage to generate an output voltage by a main switch's switching and applies power to a load, senses the current flowing to the main switch to generate a sense voltage, uses a first voltage corresponding to the current applied to the load and a sawtooth waveform signal having a first frequency to control a group frequency of the burst mode, controls the main switch's turn-on timing, and uses the first voltage and the sense voltage to determine whether to turn off the main switch, thereby controlling the main switch's switching. The converter determines the start and end of the period for switching according to the result of comparing the first voltage and the sawtooth waveform signal. Therefore, a converter for having a constant group frequency, preventing audible noise, and preventing output voltage ripple, and a driving method thereof, are provided.

Growing community of inventors

Incheon, South Korea

Kyung-Goo Lee