Magnachip Semiconductor, Inc.

Jun Sik Min

Hyoung Kyu Kim

Gyu Ho Lim

Tae Kyoung Kang

Zhi Yuan Cui

Young Gi Ryu

In Ho Hwang

Seok Min Hong

A level shifting circuit includes a transistor output unit that receives a first power supply signal and convert the first power supply signal to a second power supply signal having a different level from the first power supply signal and a current provision unit that provides a current to an output terminal of the transistor output unit when the first power supply signal of the transistor output unit is inputted to shorten a prolonged portion of the second power supply signal. Therefore, the level shifting circuit may provide an additional current to the output terminal of the transistor output unit to shorten a prolonged portion of the output voltage.

Level shifting circuit and method for the same

A power factor correction controlling circuit includes a control signal providing circuit configured to provide a control signal associated with a feedback signal, the feedback signal being controlled based on a bias signal, a pulse width modulation signal controlling circuit configured to control a pulse width modulation signal based on one of first and second bias signals and a power factor controlling circuit configured to provide a power factor control signal when an amplitude of the pulse width modulation signal reaches that of the power factor control signal. Such a circuit Is able to operate stably, regardless of a load condition and an input voltage condition.

Power factor correction controlling circuit and driving method thereof

Disclosed is a circuit for compensating a bipolar junction transistor (BJT) base current that mirrors the BJT base current to induce a mirror current that is coupled to an emitter of the BJT to decrease an emitter current by a size of the mirror current. Also disclosed is a light-emitting diode (LED) driving apparatus including an LED array, a BJT series-coupled to the LED array, a measuring unit coupled to an emitter of the BJT to measure a current flowing into the LED array, a differential amplifier configured to differentially amplify a reference voltage and the measured current to supply a base current to a base of the BJT, and a BJT base current compensation circuit as disclosed to accurately control an LED current.

Circuit for compensating bipolar junction transistor base current and LED driving apparatus having the same

There is provided a current controlling mode DC-DC converter that operates in a PWM mode or a PFM mode by adjusting a turned-on time of a gate depending on power consumption of a load. The DC-DC converter includes a first comparator that receives a first input voltage and a second input voltage and outputs a first output signal, a second comparator that receives a reference voltage for mode switching and the second input voltage and outputs a second output signal, and a first logic element that outputs a reset signal for turning off a gate at a point of time when both the first output signal and the second output signal are applied. Examples may also include additional elements to facilitate mode switching.

Current controlling mode direct current (DC)-DC converter

Provided are a ramp circuit and a DC-DC converter. The ramp circuit generates a current flowing in a resistor using voltages affected by an output voltage and an input voltage of a DC-DC converter, and generates a ramp signal through copying of the current and charging and discharging of a capacitor using a current mirror unit. The ramp signal is generated by considering the input voltage and the output voltage, and thus the ramp signal has an optimal slope to provide an adaptive response to state change in the input voltage and the output voltage. The DC-DC converter uses such a ramp circuit to facilitate its operation.

Growing community of inventors

Cheongju-si, South Korea

Jun Sik Min