Patent application number | Description | Published |
20080265791 | BACKLIGHT MODULE AND CURRENT PROVIDING CIRCUIT THEREOF - A backlight module and a current providing circuit thereof are provided. The current providing circuit includes a signal generating unit, a switching unit, a first capacitor, a transformer and an output node. The signal generating unit generates a PWM signal according to a level of a power source. The switching unit determines whether a first signal end and a second signal end of the switching unit are conducted according to the PWM signal received by a control end of the switching unit. Following a switch performed by the switching unit, the first capacitor charges and discharges through a current path provided by a primary coil of the transformer. Thereby, a secondary coil of the transformer generates a corresponding AC voltage by sensing a current change in the primary coil and outputs the AC voltage through the output node. | 10-30-2008 |
20080297499 | LCD POWER SUPPLY - An LCD (liquid crystal display) power supply includes an AC to DC converter circuit, a transformer, a DC to AC converter, and a feedback circuit. The AC to DC converter circuit couples an AC power supply to generate a DC signal. The DC to AC converter couples the DC signal to a primary side of the transformer and alternates polarities thereof so that an AC signal is generated on a secondary side of the transformer to supply for a load. The feedback circuit receives a first feedback signal indicative of power being supplied to the load and modulates the DC signal generated by the AC to DC converter circuit according to the first feedback signal. | 12-04-2008 |
20090108771 | DRIVING SYSTEM FOR ELECTRONIC DEVICE AND CURRENT BALANCING CIRCUIT THEREOF - A driving system, includes: a power supply unit for providing a first current and a second current; a first transformer having a primary side coupled to the power supply unit and a secondary side coupled to a first current balancing circuit for driving a plurality of first lamps; a second transformer having a primary side coupled to the power supply unit and a secondary side coupled to a second current balancing circuit for driving a plurality of second lamps; a balancing control circuit coupled to the power supply unit for balancing the first and the second current so that the first current and the second current are substantially equal. | 04-30-2009 |
20090237346 | INVERTER CIRCUIT OF DRIVING A LAMP AND BACKLIGHT MODULE USING THE SAME - An inverter circuit for driving a lamp and a backlight module using the same are provided. The inverter circuit includes a signal generation module, a switching unit, a first capacitor, a transformer and a first detecting module. The signal generation module generates a pulse width modulation (PWM) signal, wherein the duty cycle of the PWM signal is controlled by a feedback signal and a sensed signal. The switching unit has a control terminal receiving the PWM signal, and has a first current terminal and a second current terminal respectively coupled to a first terminal and a second terminal of the first capacitor. The transformer generates an AC driving signal to the lamp according to a signal variation of the primary winding coupled the first current terminal of the first transistor. The first detecting module generates the sensed signal according to the flowing current of the switching unit. | 09-24-2009 |
20090244946 | DC-AC CONVERTER - A DC-AC converter includes a signal generating module, a first switch, a first capacitor, a transformer, and a trigger signal generating module. The signal generating module generates a pulse width modulation (PWM) signal according to a trigger signal. The first switch has a control terminal receiving the PWM signal, and a first terminal and a second terminal coupled to a first terminal and a second terminal of the first capacitor respectively. The transformer has a primary winding coupled to the second terminal of the first switch, and a secondary winding coupled to a load. The transformer generates a driving signal to the load according to a signal variation of the primary winding. The trigger signal generating module compares a first signal outputted from the second terminal of the first switch with a phase delay signal thereof and thereby generates the trigger signal for controlling the frequency of the PWM signal. | 10-01-2009 |
20110089859 | CURRENT-TYPE DRIVER OF LIGHT EMITTING DEVICES - A current-type driver of light emitting devices is provided. The current-type driver includes a power conversion circuit, a feedback module, and a control module. The power conversion circuit modulates and generates an output voltage according to a feedback signal so as to sequentially drive a plurality of light emitting devices. The feedback module generates the feedback signal for the power conversion circuit according to the output voltage and an adjusting signal during a first period, wherein none of the light emitting devices is driven during the first period. The control module outputs the adjusting signal to the feedback module during the first period so as to allow the power conversion circuit to adjust the output voltage to a pre-drive voltage corresponding to the light emitting device which is to be driven next among the light emitting devices. | 04-21-2011 |
Patent application number | Description | Published |
20090189536 | HIGH EFFICIENCY AND LOW COST COLD CATHODE FLUORESCENT LAMP DRIVING APPARATUS FOR LCD BACKLIGHT - The invention is a driving apparatus and circuit for efficiently converting a direct current (DC) signal into an alternating current (AC) signal to drive a fluorescent lamp. A semi class E configuration which utilizes only one transistor is employed in the invention. The invention comprises a power transistor, a transformer wherein a primary winding is used as a load for the power transistor and a secondary winding is used to transfer energy to the load for the driving apparatus, i.e. the CCFL tube, and control means which extracts the frequency and current of the power transistor and corrects the deviation between the frequency of the power transistor and that of the control means. | 07-30-2009 |
20090261747 | Control system for multiple fluorescent lamps - The present invention is directed to an apparatus that drives a lighting system with multiple lamps. A phase shift mechanism is produced either by a digital method, an analog method, or a mixture of the two methods. In a digital method, phase shifts are generated by digital circuits comprising counters, a divider, an adder, and a comparator. The digital circuits analyze the signal and use the necessary information to form a series of phased driving signals. In an analog method, phase shifts are generated by analog circuits comprising ramp waveform generators, comparators, and at least one shot generator. Also, an apparatus for driving a lighting system with multiple lamps can be realized by mixing the two methods mentioned above. | 10-22-2009 |