Patent application number | Description | Published |
20110227502 | CIRCUIT AND METHOD FOR GENERATING PWM SIGNAL FOR DC-DC CONVERTER USING DIMMING SIGNAL AND LED DRIVING CIRCUIT FOR BACKLIGHT HAVING THE SAME - A pulse width modulation (PWM) signal generating circuit that generates a PWM signal for a DC-DC converter using a dimming signal is provided. The PWM signal generating circuit includes a normal PWM signal generator configured to generate a normal PWM signal based on a clock signal provided to the DC-DC converter, and a compensation PWM signal generator configured to generate a compensation PWM signal based on the clock signal and the dimming signal. | 09-22-2011 |
20120112655 | PWM SIGNAL GENERATING CIRCUIT FOR DC-DC CONVERTER USING DIMMING SIGNAL AND LED DRIVING CIRCUIT HAVING THE SAME IN DIRECT DIGITAL DIMMING METHOD - An LED driving circuit is provided. The LED driving circuit includes an input unit which receives an input dimming signal for driving an LED array, a PWM signal generating unit which extends an on-period of the input dimming signal to form an extended dimming signal, and generates a PWM signal using the extended dimming signal, a DC-DC converter which supplies output voltage to the LED array using the PWM signal, and an LED driving unit which drives the LED array using the input dimming signal. | 05-10-2012 |
20120112656 | PWM SIGNAL GENERATING CIRCUIT FOR DC-DC CONVERTER USING DIMMING SIGNAL AND LED DRIVER CIRCUIT USING THE SAME IN DIGITAL PWM METHOD HAVING FIXED PHASE MODE - A PWM signal generating circuit and method, and an LED driver circuit using same, is disclosed. The PWM signal generating circuit generates a PWM signal for a DC-DC converter using a dimming signal, and includes an oscillator which generates a first clock signal having a predetermined frequency, a synchronizing unit which synchronizes the dimming signal to the first clock signal, and a PWM signal generating unit which generates the PWM signal in response to the first clock signal having a falling edge while the synchronized dimming signal is on. | 05-10-2012 |
20120153848 | REFERENCE VOLTAGE GENERATING CIRCUIT AND LED DRIVER CIRCUIT HAVING THE SAME THEREIN - A reference voltage generating circuit used for a light-emitting diode (LED) driver circuit and a light-emitting diode (LED) driver circuit are provided. A reference voltage generating circuit used for a light-emitting diode (LED) driver circuit includes a voltage measurer configured to sequentially measure feedback voltages of a plurality of LED arrays, the LED arrays being connected to one another in parallel, a quantizer configured to search for one of the plurality of LED arrays having a lowest feedback voltage of the measured feedback voltages, a comparator configured to compare an output of the voltage measurer with a preset comparison voltage to generate a reference voltage, and a timing controller configured to control the comparator to output the generated reference voltage corresponding to the one of the plurality of LED arrays. | 06-21-2012 |
20120212141 | PWM CONTROLLING CIRCUIT AND LED DRIVER CIRCUIT HAVING THE SAME - A Light Emitting Diode (LED) driver circuit and a Pulse Width Modulation (PWM) controlling circuit thereof is provided. The LED driver circuit includes a voltage detector connected to a plurality of LED arrays, the voltage detector being configured to determine a connection status of each of the LED arrays according to a level of a feedback voltage of each of the LED arrays, and detect a minimum feedback voltage from the feedback voltage of each of the LED arrays that are determined to be connected, a controller configured to output a control signal to control boosting of the LED arrays according to the detected minimum feedback voltage, a PWM signal generator configured to output a PWM signal corresponding to the outputted control signal, and a driving voltage generator configured to supply a driving voltage commonly to the LED arrays according to the PWM signal. | 08-23-2012 |
20120212142 | PWM CONTROLLING CIRCUIT AND LED DRIVER CIRCUIT HAVING THE SAME - A Pulse Width Modulation (PWM) controlling circuit and a Light Emitting Diode (LED) driver circuit having the same are provided. An LED driver circuit includes a voltage detector connected to a plurality of LED arrays, the voltage detector being configured to determine a connection status of each of the LED arrays according to a corresponding level of the feedback voltage, and detect a minimum feedback voltage from feedback voltages of the LED arrays that are determined to be connected, a controller configured to output a control signal to one of abort and control boosting of the LED arrays according to the detected minimum feedback voltage, and a Pulse Width Modulation (PWM) signal generator configured to output a PWM signal corresponding to the outputted control signal according to an on/off state of a dimming signal that drives the LED arrays that are determined to be connected. | 08-23-2012 |
20130049614 | LED DRIVER APPARATUS - A Light Emitting Diode (LED) driver apparatus is provided. The LED driver apparatus includes: a Pulse Width Modulation (PWM) signal generator configured to generate a PWM signal, a DC-DC converter configured to provide a driving voltage of a plurality of LED arrays by using the generated PWM signal, and a sensor configured to determine whether at least one LED array among the plurality of LED arrays is in an open state in response to the driving voltage being higher than or equal to a preset first reference voltage, and the preset first reference voltage is higher than the driving voltage applied when the plurality of LED arrays are each in a working state. | 02-28-2013 |
20130147382 | LED DRIVER APPARATUS - A light emitting diode (LED) driver apparatus is provided. The LED driver apparatus includes an input unit, a PWM signal generation unit, a DC-DC converter, an LED driving unit, and a synchronization unit. The input unit is configured to receive a dimming signal. The PWM signal generation unit is configured to generate a PWM signal using an oscillator having a preset frequency. The DC-DC converter is configured to provide a driving voltage to an LED array using the generated PWM signal. The LED driving unit is configured to drive the LED array using the received dimming signal. The synchronization unit is configured to reset the oscillator based on a driving state of the LED array. | 06-13-2013 |