Patent application number | Description | Published |
20090009256 | VARIABLE-FREQUENCY OSCILLATOR - There is provided a frequency-variable oscillator that varies, even when a frequency of an input signal is varied, a frequency of an oscillation signal according to the varied frequency of the input signal. A frequency-variable oscillator according to an aspect of the invention includes: a voltage-to-current converter circuit converting a voltage level of an input signal into a current level within a predetermined range; and an oscillator circuit varying a frequency according to the current level from the voltage-to-current converter circuit and oscillating the varied frequency. | 01-08-2009 |
20090058467 | PHASE DETECTION APPARATUS - There is provided a phase detection apparatus that can accurately detect a phase difference between an input signal and a reference signal even when the input signal and the reference signal have different duty cycles. A phase detection apparatus according to an aspect of the invention may include: a pulse generation unit generating a first pulse signal on an edge of an input pulse signal, and a second pulse signal based on an edge of a reference pulse signal having a predetermined phase; and a detection unit detecting a phase difference between the first pulse signal and the second pulse signal from the pulse generation unit. | 03-05-2009 |
20090058793 | BACKLIGHT UNIT FOR SYNCHRONIZATION WITH AN IMAGE SIGNAL FOR LIQUID CRYSTAL DISPLAY - A backlight unit for synchronization with an image signal for a liquid crystal display (LCD), which can synchronize frequencies of a lamp driving signal and a lamp brightness signal with frequencies of a horizontal synchronization signal and a vertical synchronization signal, which are image signals used in an LCD panel. The backlight unit includes a synchronization part generating a first synchronized signal synchronized with a horizontal synchronization signal having a preset frequency, and a second synchronized signal synchronized with a vertical synchronization signal having a frequency different from the frequency of the horizontal synchronization signal, and a signal generation part generating a lamp driving signal for driving a lamp according to the first synchronized signal and a lamp brightness signal for controlling brightness of the lamp according to the second synchronized signal. | 03-05-2009 |
20090128055 | APPARATUS FOR DRIVING LIGHT EMITTING ELEMENT - Provided is an apparatus for driving a light emitting element. The apparatus includes a power unit, a light emitting element array, a constant-current circuit unit, and a voltage limiting circuit unit. The power unit supplies driving power. The light emitting element array includes a plurality of light emitting elements connected in series between an anode terminal connected to the power unit and a cathode terminal. The constant-current circuit unit maintains a constant current flowing through the light emitting element array according to a first tuning voltage. The voltage limiting circuit unit is connected between the cathode terminal of the light emitting element array and the constant-current circuit unit, and divides a total voltage applied between the cathode terminal of the light emitting element array and a ground according to a second tuning voltage to limit a voltage applied to the constant-current circuit unit below a predetermined voltage. | 05-21-2009 |
20100102756 | APPARATUS FOR DRIVING LIGHT EMITTING DEVICE - An apparatus for driving a light emitting device according to an aspect of the invention may include: a DC/DC converter unit generating driving power on the basis of an input voltage and supplying the generated driving power to an anode of a light emitting unit including a plurality of light emitting devices; a current source controlling to keep current flowing through the light emitting unit constant; a feedback circuit unit detecting voltage at a cathode of the light emitting unit; and a feedback coupling circuit unit coupling the output of the feedback circuit unit and the input of the DC/DC converter unit to supply the input voltage of the DC/DC converter unit according to the voltage detected by the feedback circuit unit and an output voltage of the DC/DC converter unit. | 04-29-2010 |
20100109547 | LCD BACKLIGHT INVERTER - Disclosed is a liquid crystal display (LCD) backlight inverter. The LCD backlight inverter includes a lamp open detection unit outputting a first open detection voltage for a preset time period when it is determined that a predetermined lamp is open, based on a current voltage corresponding to the current of the predetermined lamp of a plurality of lamps, a first open determination unit outputting an open detection signal when the first open detection voltage is input, a second open determination unit outputting a protection signal when it is determined that all of the plurality of lamps are open based on detection voltages of the plurality of lamps, a temporary protection determination unit outputting a frequency change signal when both the open detection signal and the protection signal are input, and an operating frequency control unit changing an operating frequency to a preset protective frequency according to the frequency change. | 05-06-2010 |
20100109563 | APPARATUS FOR DRIVING MULTI-LIGHT EMITTING DEVICES - An apparatus for driving multi-light emitting devices that drives a multi-channel light emitting unit having a plurality of light emitting channels connected in parallel with each other, each of which has a plurality of light emitting devices connected in series with each other according to an aspect of the invention may include: a DC/DC converter generating a driving voltage; a current control unit having a plurality of current sources connected between cathodes of the plurality of light emitting channels and a ground; a minimum voltage selection unit detecting a minimum detection voltage among the plurality of detected voltages at the cathodes of the plurality of light emitting channels; a first error detection unit detecting an error voltage determined by the difference between the minimum detection voltage and a predetermined first reference voltage; and a feedback coupling unit supplying the input voltage according to the error voltage and the driving voltage. | 05-06-2010 |
20100134450 | DRIVER FOR DISPLAY - A driver for display provides a driving signal having a frequency synchronized with that of an image signal when the image signal is normal and provides a driving signal having a predetermined frequency when the image signal is abnormal, thereby performing a stable operation. The driver includes a frequency detection unit detecting a frequency difference between a frequency of an inputted image signal and a frequency of a frequency-divided driving signal, a driving signal generation unit generating the driving signal having a frequency synchronized with the frequency of the image signal according to a detection result of the frequency detection unit, and a control unit stopping a frequency detection operation of the frequency detection unit when the detection result of the frequency detection unit shows an abnormal operation. | 06-03-2010 |
20120086515 | RELAXATION OSCILLATOR - There is provided relaxation oscillator. The relaxation oscillator includes: a ramp wave generator generating ramp waves by a complementary operation between a first capacitor module charged and discharged according to a first switching signal and a second capacitor module charged and discharged according to a second switching signal; a negative feedback circuit unit generating a compensation voltage for compensating errors with reference voltage by being fedback with the ramp waves; and a switching signal generator generating the first switching signal controlling the charging and discharging of the first capacitor module and the second switching signal controlling the charging and discharging of the second capacitor module from the compensation voltage and the ramp waves. As a result, the present invention can generate ramp waves having a stable frequency while preventing a frequency from being changed due to a delay or an offset of the comparator. | 04-12-2012 |
20120087160 | POWER FACTOR CORRECTION CIRCUIT - There is provided a power factor correction circuit capable of correcting a power factor of a power converting module through increasing an input current by switching a main switching element of a power converting module on the basis of a first reference wave having a slope based on a first signal and an error voltage, in particular, by limiting a switching frequency on the basis of a first reference wave having a slope based on a second signal lower than a first signal and an error voltage when the switching frequency of the main switching element increases because an input voltage of the power converting module is low. | 04-12-2012 |
20120306461 | POWER SUPPLY DEVICE, CONTROL INTEGRATED CIRCUIT THEREOF, AND METHOD OF CONTROLLING POWER SUPPLY DEVICE - There is provided a power supply device including: a first controller operating a pulse width modulation (PWM) control integrated circuit (IC) when a load is connected to an output terminal thereof; a second controller determining whether to operate the PWM control IC according to a change in voltage of an auxiliary capacitor connected to the first controller when a load is not connected to the output terminal; and a constant voltage circuit unit supplying a constant voltage to the first controller and the second controller when the PWM control IC operates. Power consumption can be considerably reduced when a load is not connected to the output terminal of the power supply device. Also, since elements for controlling the power supply device are implemented as a single integrated circuit (IC), a leakage current can be reduced to thus minimize power consumption. In addition, voltage can be supplied to the IC while reducing switching noise. | 12-06-2012 |
20130088803 | POWER SUPPLY APPARATUS - The present invention relates to a power supply apparatus including: a converting unit for converting an applied voltage into a predetermined level; a switching unit opened or closed to control current flowing in the converting unit; a detecting unit for detecting occurrence of overcurrent when a voltage applied to the switching unit is higher than a preset reference voltage; and a control unit for performing a protection operation when the overcurrent is detected more than a predetermined number of times within a predetermined time from when the overcurrent is detected and can prevent malfunction due to noises. | 04-11-2013 |
20130100566 | POWER SUPPLY DEVICE - Disclosed herein is a power supply device. The power supply device includes a conversion unit converting an applied voltage into a predetermined level, a switching unit performing an opening operation or a closing operation to control a current flowing in the conversion unit, a sensing unit sensing an occurrence of overcurrent when a voltage applied to the switching unit is equal to or larger than a reference voltage set in advance, and a control unit performing a protection operation when the overcurrent is sensed again within a protection time set in advance after a predetermined time is delayed from the time at which the overcurrent is sensed, so that malfunction due to noise is prevented. | 04-25-2013 |
20130119956 | CONTROL IC HAVING AUTO RECOVERY CIRCUIT, AUTO RECOVERY CIRCUIT OF CONTROL IC, POWER CONVERTER SYSTEM AND METHOD FOR AUTO RECOVERING CONTROL IC - The present invention relates to a control IC, an auto recovery circuit, a power converter system and a method for an auto recovering. In one embodiment, there is proposed to a control IC including: an abnormal state detection unit; a protection unit changing into a protection mode in an abnormal state and changing the protection mode into an operation mode by receiving an auto recovery signal; an IC power unit receiving the power from an input power when an IC power drops until a preset low voltage under the protection mode, blocking a power supply from the input power when the IC power reaches a preset high voltage and repeating a power supplying and blocking; and an auto restart unit counting clocks alternatively repeating a power supply signal and a supply block signal and supplying the auto recovery signal when the number of counts reaches a preset value. | 05-16-2013 |
20130134901 | DRIVING APPARATUS FOR LIGHT EMITTING DIODE AND CONTROL METHOD THEREOF - There are provided a driving apparatus for a light emitting diode (LED) which may accurately display a desired color of light by adjusting a color coordinate value in accordance with an input brightness value, and a control method thereof. The driving apparatus includes a control unit receiving a brightness value and a color coordinate value of an LED desired to be controlled and controlling LED driving by adjusting the color coordinate value in accordance with the received brightness value; and a driving unit driving the LED in accordance with controlling of the control unit. | 05-30-2013 |
20130194832 | CONVERTER DRIVING CIRCUIT, DUAL-MODE LLC RESONANT CONVERTER SYSTEM, AND METHOD OF DRIVING DUAL-MODE LLC RESONANT CONVERTER - Disclosed herein are a converter driving circuit for adjusting a variable range of a driving control voltage according to an amplitude and frequency change of a feedback voltage, a dual-mode LLC resonant converter system, and a method of driving the dual-mode LLC resonant converter. | 08-01-2013 |