Patent application number | Description | Published |
20130002162 | LED BACKLIGHT DRIVING CIRCUIT - A light emitting diode (LED) backlight driving circuit is disclosed in the present disclosure. The LED backlight driving circuit in configured to power an LED backlight module, and comprises: a voltage stabilizing circuit, being configured to receive an input voltage and filter the input voltage to output a stabilized direct current (DC) voltage; a first boost circuit and a second boost circuit connected with the voltage stabilizing circuit respectively, being configured to receive the stabilized DC voltage and boost the stabilized DC voltage for output to the LED backlight module; and a selection control circuit, being configured to alternately select one of the first boost circuit and the second boost circuit to power the LED backlight module. The LED backlight driving circuit of the present disclosure can improve the voltage boosting efficiency and reduce the cost, so it is of great utility. | 01-03-2013 |
20130057462 | LED Driving Circuit, Liquid Crystal Display Device and Driving Method Thereof - The present invention discloses a LED driving circuit, a LCD device and a driving method thereof wherein said LED driving circuit comprises LED strings, a power supply module for supplying power for the LED strings under the control of the on/off signal, and an output capacitor which is in parallel connection with the LED strings; and said LED driving circuit also comprises a discharge module which is in parallel connection with the output capacitor and operates when the on/off signal is at low level. Because the output capacitor is in parallel connection with a controllable discharge module, the discharge module can be connected at the interval between ON and OFF to discharge the output capacitor. The present invention solves the problem of extra charges remaining in the capacitor so that the LED can not be turned on twice in ON operation; meanwhile, the consumption of the circuit under normal operation is not affected. | 03-07-2013 |
20130069553 | LED DIMMING DRIVE DEVICE, METHOD AND LCD - A light emitting diode (LED) dimming drive device, an LED dimming drive method and a liquid crystal display (LCD) are disclosed. The LED dimming drive device comprises a plurality of dimming control circuits each comprising one dimmer switch and a delay setting circuit for setting a different delay time for each dimming control circuits. Each of the dimming control circuits further comprises a clock delay circuit for receiving a pulse width modulation (PWM) signal, timing according to the delay time, and outputting the PWM signal to the dimmer switch when the delay time expires. Different delay times can be used to control the output of PWM signals and further control the on or off of the dimmer switches. This can avoid the noises or electromagnetic (EM) interferences occurred by a large amount of energy transmitted into the LED paths when the dimmer switches is turned on. | 03-21-2013 |
20130120677 | TEMPERATURE CONTROL METHOD AND APPARATUS FOR LIGHT EMITTING DIODE AND LIQUID CRYSTAL DISPLAY - A temperature control method for light emitting diode (LED) is disclosed, and the method comprises the following steps: acquiring the present temperature of the LED during the light emission of the LED; obtaining a driving electric current corresponding to the present temperature based on the present temperature of the LED; and driving the LED based on the driving electric current. This invention further discloses a temperature control device for the LED and a liquid crystal display. | 05-16-2013 |
20130127348 | LED DRIVE CIRCUIT - An LED drive circuit is disclosed, which comprises a square wave generator configured to generate a square-wave signal for driving an LED unit, an LLC resonance circuit configured to transform the square-wave signal outputted by the square wave generator into a sinuous wave of a reduced voltage level, and the LED unit comprising at least one LED sub-unit. The LED sub-unit comprises at least a first LED lamp set and a second LED lamp set connected in parallel, and LEDs of the first LED lamp set are disposed in a direction opposite to those of the second LED lamp set. The square wave generator, the LLC resonance circuit and the LED unit are connected in sequence. The LED drive circuit of the present disclosure can drive an LED and has a reduced cost. | 05-23-2013 |
20130147381 | DRIVING CIRCUIT AND DRIVING METHOD FOR LIGHT EMITTING DIODE AND DISPLAY APPARATUS USING THE SAME - The present invention provides a driving circuit and a driving method for light-emitting diodes (LEDs), and a display apparatus using the same. The driving circuit comprises a power switch and a dimmer circuit. The method comprising: detecting a duty of a pulse width modulation (PWM) dimming signal; and when the duty of the PWM dimming signal is less than the predetermined duty, providing an analog dimming signal to the driving circuit. The present invention can be applicable to a display apparatus, and improve a noise problem when a duty of a conventional dimming is too low. | 06-13-2013 |
20130271443 | DRIVING CIRCUIT OF BACKLIGHT MODULE AND DISPLAY APPARATUS USING THE SAME - The present invention provides a driving circuit of a backlight module and a display apparatus using the same. The driving circuit comprises at least one transistor connected to light-emitting diodes (LEDs), a constant-current circuit connected to the transistor, a power resist connected to the transistor in parallel; and a power switch connected between the transistor and the power resist, wherein a switch signal is transmitted to the power switch, and a signal level of the switch signal in a three-dimensional (3D) image mode is higher than another signal level of the switch signal in a two-dimensional (2D) image mode. The present invention can be applicable to the display apparatus for raising a brightness of the backlight module in the 3D image mode. | 10-17-2013 |
20130271500 | LED Backlight Driving Circuit, Backlight Module, and LCD Device - The invention provides an LED backlight driving circuit, a backlight module, and an LCD device. The LED backlight driving circuit includes LED light string(s); an anode of the LED light string is connected with a boost circuit, and a cathode of the LED light string is connected with a buck-boost circuit. The invention has the advantages that the limitation of the maximum voltage supplied by the single boost circuit is broken, the voltage difference between both ends of the LED light string is added, namely more LED lights can be connected in series in a single channel. Therefore, the requirement is met by a single string of LEDs or few strings of LEDs instead of the original multiple strings of LEDs, the difficulty of the current sharing of the LED light strings is reduced, the type selection of current sharing IC is convenient, equipment involved therein doesn't need a high voltage resistance, and the use of the current sharing IC is reduced, thereby favoring cost reduction. | 10-17-2013 |
20130271701 | LED Backlight Drive Circuit, Liquid Crystal Display Device and Driving Method - The invention discloses an LED backlight drive circuit, an LCD device and a driving method. The LED backlight drive circuit includes a power source; an output capacitor and an LED lightbar which is connected in series with a first controllable switch are in parallel connection, and then are arranged between the output terminal and the ground terminal of the power source. The LED backlight drive circuit further includes a first comparator; a cathode of the first comparator is connected to a first reference voltage, an anode of the first comparator is coupled with the output terminal of the power source, and the output terminal of the first comparator is coupled with a control end of the first controllable switch; when the anode voltage of the first comparator exceeds the cathode voltage, the output terminal of the first comparator drives the first controllable switch to be conducted. In the invention, the LED lightbar only can be conducted at the predetermined voltage. Thus, the LED will be unable to be lighted even if the electric quantity is stored in the output capacitor; only when the output voltage achieves the predetermined voltage in the complete ON operation, the first controllable switch is able to be conducted, which solves the problem of LED blinking in the ON operation. | 10-17-2013 |
20130285571 | LED Backlight drive circuit, LCD Device and Driving Method - The invention provides an LED backlight drive circuit, an LCD device and a driving method. The LED backlight drive circuit comprises a plurality of LED lightbars which are arranged in parallel connection, and a detection module; a comparison unit is arranged in said detection module, the comparison ends of the comparison unit are respectively coupled to the output ends of the LED lightbars, and the reference end thereof is coupled with an adjustable reference voltage module. In the invention, because the comparison unit is used, and the reference end of the comparison unit is coupled to an adjustable reference voltage module, different reference voltages are selected in accordance with different output end voltages of the LED lightbars of the LCD device. If the voltage difference between the output end voltage of the LED lightbar and the reference voltage is controlled within a reasonable range, the comparison accuracy can be effectively improved. The maximum voltage difference of the LED lightbar is fed back to the power source end of the drive circuit to regulate the output of the power source. | 10-31-2013 |
20130286311 | LCD Device and a Transforming Circuit Thereof - The present invention proposes a liquid crystal display device and a transforming circuit thereof. One terminal of a first coil connects to input voltage. One terminal of a energy-storage unit connects to the other terminal of the first coil. One terminal of a second coil connects to the other terminal of the energy-storage unit, and the other terminal of the second coil connects to the light source. An input terminal of a unidirectional unit connects to the one terminal of the first coil which is connected to the input voltage, and the output terminal connected to the one terminal of the second coil which is connected to the light source. A driving signal is fed into a controlling terminal of a switch unit. A first terminal of the switch unit is grounded, and the second terminal of the switch unit is connected a medial point between the first coil and the energy-storage unit. | 10-31-2013 |
20130300642 | BACKLIGHT UNIT WITH CHANGING OSCILLATION FREQUENCY IN STEREOSCOPIC MODE AND LIQUID CRYSTAL DISPLAY USING THE SAME - A liquid crystal display for displaying either a flat image or a stereoscopic image, comprising: a panel; and a backlight unit for providing a light source to the panel. The backlight unit comprising: a switch circuit and an oscillator. One end of the switch circuit is electrically connected with a first resistor, and another end of the switch circuit is electrically connected with a second resistor. When the switch circuit is turned on, the first resistor is connected with the second resistor in parallel. The oscillator is electrically connected with the first resistor and the switch circuit. When the switch circuit is turned off, the oscillator outputs a first frequency, and when the switch circuit is turned on, the oscillator outputs a second frequency. | 11-14-2013 |
20130300770 | LED Backlight Driving Circuit, Liquid Crystal Display Device, and Driving Method - The invention discloses an LED backlight driving circuit, an LCD device, and a driving method. The LED backlight driving circuit includes a plurality of LED light strings which are arranged in parallel; each LED light string is correspondingly connected with a dimming branch in series. The LED backlight driving circuit further includes a plurality of controllable disconnectors; one end of the controllable disconnector is connected to at least two LED light strings, and the other end of the controllable disconnector is connected with an equal amount of dimming branches; at the moment, only one of the dimming branches connected with the same controllable disconnector can be conducted. In the invention, on the premise of ensuring that the whole brightness is not variously reduced, the number of the controllable disconnector can be reduced by sharing the same controllable disconnector, thereby reducing the cost. | 11-14-2013 |
20130300983 | LED Backlight Driving Circuit, Liquid Crystal Display Device and Driving Circuit - The invention discloses an LED backlight driving circuit, an LCD device and a driving circuit. The LED backlight driving circuit includes a power supply module, an LED lightbar coupled with an output terminal of the power supply module, a dimming module coupled with the output terminal of the LED lightbar, and the LED backlight driving circuit further includes a transfer switch. A first input terminal of the transfer switch is coupled to the output terminal of the LED lightbar, and a second input terminal of the transfer switch is coupled to a feedback voltage. The output terminal of the transfer switch is coupled to the power supply module. The transfer switch is switched to the first input terminal when the dimming module is ON, and the transfer switch is switched to the second input terminal when the dimming module is OFF. Therefore, the LEDs of the invention can operate normally within the short dimming cycle. The invention only adds one transfer switch, the circuit is simple and does not increase the circuit area, and the cost is low. | 11-14-2013 |
20130307878 | LED Backlight Driving Circuit, Backlight Module, and LCD Device - The invention provides an LED backlight driving circuit, a backlight module, and an LCD device. The LED backlight driving circuit includes an LED light string; an input end of the LED light string is directly connected with an input end of a power source, and an output end of the LED light string is coupled with a buck module. In the invention, because the output end of the LED light string is in series connected with the buck module, the LED light string is connected in series between an input voltage and an output voltage, and a part of LEDs are directly supplied by the input voltage without the first stage conversion. Thus, the energy supplied by the buck module is reduced, the conversion efficiency is improved, the energy efficiency is increased, the requirement of the buck module to withstand voltage is reduced, and the device standard is decreased, thereby favoring cost reduction. | 11-21-2013 |
20130322059 | LED Backlight System and Display Device - The present invention provides an LED backlight system and display device. Backlight system includes power source module, LED array, master switch module, current detection module, current equalizer module and current shunt module. LED array is connected to power source module and includes LED strings with common anode. Master switch module includes first switch transistors for receiving switch control PWM signal of LED strings. Current detection module outputs current feedback signals corresponding to currents of LED strings. Current equalizer module is connected to current detection and includes equalizer control unit and equalizer switch unit. Based on current feedback signal, equalizer control unit controls on-and-off of equalizer switch unit. Current shunt module is connected in parallel with current equalizer module and performs current shunt on current equalizer module. As such, the present invention reduces energy-consumption of current equalizer module and temperature of LED drive chip. | 12-05-2013 |
20130335923 | PCB for LCD Device and LCD Device - The invention relates to the field of LCDs, and more particularly to a PCB for an LCD device and an LCD device. The PCB includes a front face and a back face; the front face of the PCB is a face for densely arranging components, and the back face is a face without densely arranged components; the back face of the PCB is provided with a jumper wire for dissipating heat, and the jumper wire is connected with a terminal of the component. The heat of the component is transmitted to the jumper wire by the terminal, and the jumper wire is used for auxiliarily strengthening heat dissipation. Because the back face of the PCB is the face without densely arranged components, the temperature of the back face is lower than that of the front face of the PCB, and the temperature difference between the jumper wire and the environmental of the back face of the PCB is large. Thus, the heat is rapidly transmitted, and the heat dissipating effect is significantly improved. | 12-19-2013 |
20140002772 | LED BACKLIGHT DRIVING CIRCUIT, BACKLIGHT MODULE, AND LCD DEVICE | 01-02-2014 |
20140009455 | LED BACKLIGHT DRIVING CIRCUIT, BACKLIGHT MODULE, AND LCD DEVICE - The present disclosure discloses a light emitting diode (LED) backlight driving circuit, a backlight module, and a liquid crystal display (LCD) device. The LED backlight driving circuit includes an LED lightbars. An output end of the LED lightbar is connected with a control integrated circuit (IC) in series, and is also connected with a shunt controllable switch. The shunt controllable switch is switched on when a voltage of the output end of the LED lightbar exceeds a preset value and is switched off when the voltage is less than the preset value. In the present disclosure, because a shunt controllable switch is connected in parallel in the control IC, when the LED lightbars are short-circuited, the shunt controllable switch is switched on, a part of current flows towards the shunt controllable switch, and the burden of the control IC is alleviated. Thus, the temperature of the control IC is reduced. | 01-09-2014 |
20140016304 | LED BACKLIGHT DRIVING CIRCUIT, BACKLIGHT MODULE, AND LCD DEVICE - A backlight driving circuit includes a plurality of display areas, and each display area includes a first LED light cluster and a second LED light cluster which are symmetrical. The first LED light cluster and the second LED light cluster are connected in series to form a plurality of LED lightbars connected in parallel connection at two ends of the power source of the backlight driving circuit. Because the LED light clusters of the same display area are connected in series namely more than two small lightbars are connected in series to form a large LED lightbar, the small lightbars only occupy one pin of the constant current circuit. The LEDs on both sides of the same display area of the 3D display device can be simultaneously turned on or simultaneously turned off, and can be completely connected in series for use. | 01-16-2014 |
20140085946 | POWER SYSTEM AND STARTING METHOD THEREOF - A power system and a starting method thereof includes a power output circuit, a loop circuit, a soft start circuit, and a constant-current source that supplies power to the soft start circuit. The loop circuit includes a loop circuit capacitor. The power system further includes a precharge circuit that charges the loop circuit capacitor, and the precharge circuit charges the loop circuit capacitor when the soft start circuit charges the power output circuit. | 03-27-2014 |
20140092071 | 3D TV DIMMING SYSTEM AND DIMMING METHOD - A three-dimensional (3D) television (TV) dimming system includes a TV control board, a light bar load controlled by the TV control board, and a power board that supplies power to the light bar load. The TV control board is directly coupled with the power board, and the TV control board feeds back the 3D signal to the power board when the TV control board outputs a 3D signal. | 04-03-2014 |
20140139419 | BACKLIGHT DRIVING CIRCUIT, BACKLIGHT MODULE, AND LCD DEVICE - A backlight driving circuit includes a power supply module, an inductor connected with an output end of the power supply module, and a light emitting diode (LED) lightbar connected with the inductor in series. A monitoring module detecting an output current of the inductor is coupled between the inductor and the LED lightbar. A controllable switch is connected between an output end of the inductor and a grounding terminal of the backlight driving circuit. The monitoring module is coupled with the controllable switch. When the output current of the inductor is lower than a preset value, the monitoring module controls the controllable switch to turn on. | 05-22-2014 |
20140145646 | LED VOLTAGE ADJUSTMENT DEVICE AND DRIVE SYSTEM THEREOF - The present invention provides LED voltage adjustment device and drive system thereof. The device includes PI regulator, with negative terminal connected to negative terminal of LED light bar to receive negative terminal voltage of light bar and positive terminal of PI regulator being for receiving reference voltage; integrator, for performing integral on output signal of PI regulator; a subtractor, with positive input terminal receiving output signal from PI regulator and negative terminal receiving overcurrent protection detection voltage from boost converter for driving light bar, and subtracting overcurrent protection detection voltage from output signal of PI regulator; comparator, with positive terminal receiving output signal from integrator and negative terminal receiving output signal from subtractor; and integrated circuit (IC) module, for receiving output signal from comparator and based on received output signal to control a control signal to conduct or cut off switch transistor of boost converter. | 05-29-2014 |
20140176014 | LED BACKLIGHT DRIVER CIRCUIT - A light emitting diode (LED) backlight driver circuit includes an LED lightbar and a driver module of the LED lightbar. The driver module includes a backlight driver integrated chip (IC) regulating an output voltage of the driver module, and the backlight driver IC includes a first comparator correcting the output voltage of the driver module. The output end of each LED lightbar is coupled to an inverting input end of the first comparator, and a non-inverting input end of the first comparator is coupled to a protection module. The protection module includes a detection unit detecting an output current of the driver module. When the output current of the driver module detected by the detection unit is greater than a preset first current, the protection module outputs a first reference voltage to the non-inverting input end of the first comparator. When the output current of the driver module detected by the detection unit is lower than the preset first current, the protection module outputs a second reference voltage, which is lower than the first reference voltage, to the non-inverting input end of the first comparator. | 06-26-2014 |
20140197742 | LED DRIVE CIRCUIT - An LED drive circuit, which comprises a transformer, an MOS tube, a power regulating resistor, a direct current isolation circuit, a rectifying circuit, and a voltage control circuit; when the voltage of the control terminal of the voltage control circuit is higher than the threshold voltage of the MOS tube, the MOS tube is on, a current from an external power supply flows through the first winding of the transformer, the MOS tube and the power regulating resistor successively; when the voltage of the power regulating resistor is close to the voltage of the reference terminal of the voltage control circuit, the MOS tube is cut off, the second winding of the transformer charges the capacitor of the MOS tube via the direct current isolation circuit, the rectifying circuit is on, and the first winding of the transformer supplies power to the LED load via the rectifying circuit. | 07-17-2014 |
20140292630 | LED BACKLIGHT DRIVING CIRCUIT, LCD DEVICE, AND METHOD FOR DRIVING THE LED BACKLIGHT DRIVING CIRCUIT - A light emitting diode (LED) backlight driving circuit of the present disclosure includes a monitor module, a first light cluster, a first boost voltage module that drives the first light cluster a second light cluster, and a second boost voltage module that drives the second light cluster. The first boost voltage module includes a first detection unit that detects an output current of the first boost voltage module, and the second boost voltage module includes a second detection unit that detects an output current of the second boost voltage module. The monitor module includes a current comparing unit coupled to the first detection unit and the second detection unit, and an actuator coupled to the current comparing unit. The actuator controls running states of the first boost voltage module and the second boost voltage module. | 10-02-2014 |
20140333204 | LED BACKLIGHT DRIVING CIRCUIT, LCD DEVICE, AND METHOD FOR DRIVING THE LED BACKLIGHT DRIVING CIRCUIT - A light emitting diode (LED) backlight driving circuit includes an LED light bar, a power supply that drives the LED light bar to light, a short-circuit protection unit, and a divider resistor. An output end of the LED light bar is coupled to the short-circuit protection unit and the divider resistor. The short-circuit protection unit includes a comparing unit and a driving unit coupled to the comparing unit. Voltage of two ends of the divider resistor is regarded as a feedback voltage, and the feedback voltage and a first reference voltage are input to the comparing unit. When a difference value of the first reference voltage subtracted from the feedback voltage is greater than a preset deviation value; the driving unit controls the power supply to turn off. When brightness of one normal LED light bars reaches a maximum, the first reference voltage is greater than or equal to voltage of two ends of the divider resistor corresponding to the one normal LED light bar. | 11-13-2014 |
20140333518 | LED BACKLIGHT DRIVING CIRCUIT, LCD DEVICE, AND METHOD FOR DRIVING THE LED BACKLIGHT DRIVING CIRCUIT - A light emitting diode (LED) backlight driving circuit includes a power module, a constant current driving module, and an LED light bar coupled to the power module. The power module is coupled to a power-voltage collecting module outputting a second comparison voltage, and the LED light bar is coupled to a light-bar-voltage collecting module outputting a first comparison voltage. The constant current driving module includes a switching unit and a control unit coupled to the switching unit and adjusting an output voltage of the power module, the first comparison voltage and the second comparison voltage are sent to the switching unit, and a preset reference voltage is sent to the switching unit. When the first comparison voltage deviates from the reference voltage, and an absolute value of the reference voltage VF subtracted from the first comparison voltage exceeds a preset deviation range of a voltage, the switching unit outputs the first comparison voltage to the control unit. When the absolute value of the reference voltage VF subtracted from the first comparison voltage is within the preset deviation range of the voltage, the switching unit ouputs the second comparison voltage to the control unit. | 11-13-2014 |
20140375213 | LED BACKLIGHT DRIVING CIRCUIT AND METHOD FOR DRIVING THE LED BACKLIGHT DRIVING CIRCUIT - A light emitting diode (LED) backlight driving circuit includes a plurality of LED light bars, a power supply driving the LED light bars to light, and comparing units corresponding to the LED light bars one by one. A first input end of the comparing unit is coupled to a cathode end of the LED light bar, and a second input end of the comparing unit receives a first reference voltage. Each of the LED light bars is connected in series with a switching unit, an output end of the comparing unit is coupled to a statistic unit, an output end of the statistic unit is coupled to driving units corresponding to the switching units one by one and controlling the switching units to turn on/off. The statistic unit divides the LED light bars into two groups according to a logic state output by the comparing unit, and controls the driving unit to turn off one of two groups of LED light bars having a fewer number than the other group of the LED light bars. | 12-25-2014 |
20150054859 | DRIVING CIRCUIT AND DRIVING METHOD FOR LIGHT EMITTING DIODE AND DISPLAY APPARATUS USING THE SAME - The present invention provides a driving circuit and a driving method for light-emitting diodes (LEDs), and a display apparatus using the same. The driving circuit comprises a power switch and a dimmer circuit. The method comprising: providing a pulse width modulation (PWM) dimming signal and a high frequency dimming signal; and multiplying the PWM dimming signal and the high frequency dimming signal for providing a driving signal to the power switch. The present invention can improve a dimming effect of the LEDs. | 02-26-2015 |
20150069927 | LCD BACKLIGHT MODULE AND METHOD FOR CONTROLLING THE SAME - The present invention discloses an LCD backlight module, which includes a backlight source and a backlight source control device, the backlight source control device comprising: a first switch; a boost module; a control module, utilized to control the first switch, so that the backlight source is switched on off under the control of the control module, and utilized to control the boost module, so that the boost module keeps outputting the voltage after the backlight source is turned off by the first switch. | 03-12-2015 |