Patent application number | Description | Published |
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 |
20120319605 | ILLUMINATION DRIVING APPARATUS - A fixture-compatible, dimmable illumination driving apparatus including: a rectifying unit rectifying a phase-controlled waveform of an alternating current (AC) power; a comparing unit comparing an output waveform of the rectifying unit with a first voltage according to a preset reference clock; a reference voltage generating unit generating a reference voltage corresponding to the number of high signals higher than the first voltage among outputs of the comparing unit during one cycle of the output waveform; and a pulse width modulation (PWM) signal generating unit generating a PWM signal from the reference voltage and a feedback voltage. | 12-20-2012 |
20120319609 | LIGHT EMITTING DIODE DRIVER HAVING OFFSET VOLTAGE COMPENSATING FUNCTION - There is provided a light emitting diode (LED) driver having an offset voltage compensating function compensating for an offset voltage generated at the time of driving of an LED, the LED driver including: a driving unit detecting a current flowing in an LED unit having at least one LED, as a voltage and controlling the current flowing in the LED unit according to a comparison result between the detected voltage and a reference voltage having a preset voltage level; and an offset compensating unit integrating a voltage difference between the detected voltage and the reference voltage and adding or subtracting a compensating current according to an integration result to thereby compensate for an offset. | 12-20-2012 |
20130033191 | LIGHT EMITTING DIODE DRIVING DEVICE AND METHOD THEREOF - There are provided a light emitting diode (LED) driving device allowing for an increase in an LED driving rate by discharging a charge stored in a capacitor during a certain period of time and a method thereof. The LED driving device includes: a driving unit detecting a current, as a voltage, the current flowing across an LED unit having at least one LED, controlling the current flowing across the LED unit according to a comparison result between the detected voltage and a reference voltage having a pre-set voltage level, and having a capacitor stabilizing an operation of the LED unit when the LED unit is driven; and a discharging unit discharging a charge stored in the capacitor during a pre-set discharge time when the LED unit is initially driven. | 02-07-2013 |
20140035473 | ILLUMINATION DRIVING APPARATUS FOR LIGHT EMITTING DIODE AND METHOD THEREOF - There is provided an illumination driving apparatus for a light emitting diode, the apparatus including: a light emitting unit including M number of light emitting diodes (LEDs) connected in series and driven by an output voltage rectified in a rectifying unit; an LED switch unit including N number of LED switches connected in parallel with at least N number of the M LEDs, respectively, and connected in series; an LED switch control signal generating unit comparing the output voltage of the rectifying unit with each of the first to Nth preset reference voltages to generate N number of LED switch control signals controlling the LED switch unit; and an LED switch controlling unit transferring the N number of LED switch control signals to the LED switch unit. | 02-06-2014 |
20140176089 | PHASE SHIFT CIRCUIT AND POWER FACTOR CORRECTION CIRCUIT INCLUDING THE SAME - There are provided a phase shift circuit and a power factor correction circuit including the same. The phase shift circuit includes a ramp generation unit charging or discharging a capacitor connected to a switch device to generate a ramp signal, a reference signal generation unit generating a predetermined reference signal from the ramp signal, and a comparison unit comparing the ramp signal with the reference signal to generate a clock signal, wherein at least one of the reference signal generation unit and the comparison unit changes a negative or positive value of offset components included in the reference signal or the ramp signal within every operating period of the switch device. | 06-26-2014 |
20140185339 | POWER FACTOR CORRECTION CIRCUIT - There is provided a power factor correction circuit including: a power conversion circuit unit controlling an inductor current according to a switching signal applied to a main switch to convert an external input voltage into an output voltage having a predetermined range; an imbalance detection circuit outputting an imbalance state signal when the external input voltage is in an unbalanced state by using the inductor current; and a soft start circuit unit performing soft starting by adjusting the switching signal when the imbalance state signal is output by the imbalance detection circuit unit. | 07-03-2014 |
20150102786 | PFC CONTROL CIRCUIT, ACTIVE PFC CIRCUIT AND PFC CONTROL METHOD - The present invention relates to a PFC control circuit, an active PFC circuit, and a PFC control method. According to an embodiment of the present invention, a PFC control circuit including: an inductor current sensing unit for sensing an inductor current of a PFC circuit; an output voltage feedback unit for outputting a feedback output signal; a sensing and feedback signal application unit for outputting a sensing voltage signal during switching duty on of the PFC circuit and adding the feedback output signal to the sensing voltage signal to output the added signal during switching duty off of the PFC circuit; and a PFC control unit for generating a comparison signal and generating a duty control signal from the comparison signal and a first reference signal to make variations due to an internal offset be removed or reduced is provided. | 04-16-2015 |