Patent application number | Description | Published |
20090154543 | Using a Triangular Waveform to Synchronize the Operation of an Electronic Circuit - An electronic circuit exhibiting synchronization with an external synchronization signal, the electronic circuit comprising: an input connection arranged to receive a synchronization input signal; a triangular waveform oscillator operatively associated with the synchronization signal input connection and responsive to a condition of the received synchronization input signal to initiate a triangular waveform; and a pulse train generator operatively associated with the triangular waveform oscillator, the pulse train generator arranged to generate a plurality of pulse trains having a fixed non-zero phase relationship between them and a frequency responsive to the condition of the synchronization input signal. | 06-18-2009 |
20090195174 | ARRANGEMENT SUITABLE FOR DRIVING FLOATING CCFL BASED BACKLIGHT - A backlighting arrangement constituted of: a means for receiving an alternating current comprising a first lead and a second lead; at least one luminaire; and at least one first balancing transformer pair each associated with a particular one of the at least one luminaire, the primary of a first balancing transformer of the first balancing transformer pair serially coupled between the first lead of the means for receiving an alternating current and a first end of each of the at least one luminaire, and the primary of a second balancing transformer of the first balancing transformer pair serially coupled between the second lead of the means for receiving an alternating current and a second end of each of the at least one luminaires The secondaries of all of the at least one first balancing transformer pair are serially connected in a closed in-phase loop. | 08-06-2009 |
20090195175 | Direct Coupled Balancer Drive For Floating Lamp Structure - A backlighting arrangement constituted of a driving transformer arrangement; a plurality of lamp pairs, each of the constituent lamps of the plurality of lamp pairs exhibiting a first electrical connection and a second electrical connection; and a plurality of balancing transformers, each comprising a primary winding and a secondary winding magnetically coupled to the primary winding, and each associated with a particular one of the plurality of lamp pairs, the primary winding of each of the plurality of balancing transformers serially connected between the second electrical connections of the constituent lamps of the associated lamp pair, the secondary windings of the plurality of balancing transformers serially connected in phase, with a first end of the serially connected secondary windings of the balancing transformers connected to one phase output of the driving transformer arrangement. | 08-06-2009 |
20090195178 | BALANCING ARRANGEMENT WITH REDUCED AMOUNT OF BALANCING TRANSFORMERS - A backlighting arrangement constituted of: a driving transformer; at least one balancing transformer; a plurality of luminaires, a first end of each of the plurality of luminaires connected to a high voltage lead of the driving transformer and a second end of each of the plurality of luminaires connected to a unique end of a winding of the at least one balancing transformer, wherein each pair of the luminaires is associated with a particular winding of one of the at least one balancing transformers, and wherein the first end and the second end of each of the luminaires is in physical proximity of the driving transformer and the at least one balancing transformer, the constituent lamps of the luminaires arranged in parallel and generally extending axially away from the proximity of the driving transformer. | 08-06-2009 |
20090206767 | SPLIT PHASE INVERTERS FOR CCFL BACKLIGHT SYSTEM - An apparatus and method for driving a lamp are provided. In one embodiment, an inverter having four switching elements is split into two inverter arms that are deployed at separate terminals of a floating lamp structure to achieve even light output. A controller drives both inverter arms such that power switching lines do not cross the floating lamp structure. In one embodiment, the controller adjusts the brightness of the lamp structure by adjusting the phase difference between outputs of a first inverter arm relative to a second inverter arm. In one embodiment, the controller adjusts the brightness by symmetrically pulse width modulating the outputs of the first inverter arm and the second inverter arm. | 08-20-2009 |
20090267521 | BALANCING TRANSFORMERS FOR MULTI-LAMP OPERATION - A ring balancer comprising a plurality of balancing transformers facilitates current sharing in a multi-lamp backlight system. The balancing transformers have respective primary windings separately coupled in series with designated lamps and have respective secondary windings coupled together in a closed loop. The secondary windings conduct a common current and the respective primary windings conduct proportional currents to balance currents among the lamps. The ring balancer facilitates automatic lamp striking and the lamps can be advantageously driven by a common voltage source. | 10-29-2009 |
20090289569 | CCFL CONTROLLER WITH MULTI-FUNCTION TERMINAL - A cold cathode fluorescent lamp controller exhibiting a multi-function terminal and operative alternately in a strike mode and a run mode, the controller comprising: a phase locked loop arranged for synchronization of an oscillator, associated with the controller, with an external signal, the phase locked loop comprising a capacitor coupled to the multi-function terminal; and a soft start circuit arranged to limit drive current immediately after reset of the controller responsive to a signal at the multi-function terminal. In one embodiment the controller further comprises an error detection circuit arranged to output an error signal on the multi-function terminal. In one embodiment the controller further comprises a frequency sweeping circuit operative to sweep the frequency of a drive signal during the strike mode of the controller, the frequency of the drive signal being swept by the frequency sweeping circuit responsive to a signal at the multi-function terminal. | 11-26-2009 |
20100123400 | METHOD AND APPARATUS FOR DRIVING CCFL AT LOW BURST DUTY CYCLE RATES - A cold cathode fluorescent lamp controller constituted of a pulse generator exhibiting a cycle period; a burst dimming control operative to set a burst dimming duty cycle for the pulse generator; a comparator arranged to receive a signal indicative of the value of current through a load driven by the pulse generator and compare the received signal to a reference signal; an error detection circuit operative to shut down the pulse generator responsive to an output of the comparator indicating that the received signal is less than the reference signal for a predetermined number of cycles of the pulse generator; and a disable circuit arranged to prevent, when the set burst dimming duty cycle is less than a predetermined value, the shut down of the pulse generator responsive to the output of the comparator indicating the received signal is less than the reference signal. | 05-20-2010 |
20100327761 | INTEGRATED BACKLIGHT CONTROL SYSTEM - A lighting arrangement constituted of: a power factor correction circuit; a lighting controller operative at an electrical potential consonant with the electric potential of the output of the power factor correction circuit; a switching network, coupled to the output of the power factor correction circuit and to respective outputs of the lighting controller; a transformer, a primary winding of the transformer coupled to the output of the switching network; and at least one luminaire coupled to at least one secondary winding of the transformer and arranged to be driven by the at least one secondary winding, the lighting controller operative to control the switching network via the respective outputs to switchably pass current from the power factor correction circuit through the primary winding, thereby powering the at least one luminaire. | 12-30-2010 |
20110181204 | BALANCING TRANSFORMERS FOR MULTI-LAMP OPERATION - A ring balancer comprising a plurality of balancing transformers facilitates current sharing in a multi-lamp backlight system. The balancing transformers have respective primary windings separately coupled in series with designated lamps and have respective secondary windings coupled together in a closed loop. The secondary windings conduct a common current and the respective primary windings conduct proportional currents to balance currents among the lamps. The ring balancer facilitates automatic lamp striking and the lamps can be advantageously driven by a common voltage source. | 07-28-2011 |
20110304280 | LIPS BACKLIGHT CONTROL ARCHITECTURE WITH LOW COST DEAD TIME TRANSFER - A driving circuitry arranged to pass a dead time over an isolation transformer, the driving circuitry constituted of: a three-state driver arranged to output a first signal, the first signal selectively at one of two complementary voltage levels and a high impedance state; a first capacitor, a first end of the first capacitor coupled to receive the first signal; and a first isolation transformer, a first end of a first winding of the first isolation transformer coupled to a second end of the first capacitor. | 12-15-2011 |
20120013259 | LED STRING DRIVER ARRANGEMENT WITH NON-DISSIPATIVE CURRENT BALANCER - A solid state lighting driver arrangement exhibiting a plurality of LED strings receiving power from a single power source, the single power source providing a discontinuous current, wherein a plurality of first windings are provided, each associated with a particular LED string and coupled to provide current balancing between the various LED strings. The discontinuous current resets the windings during the off time or during a reversal period. In one particular embodiment, a second winding is magnetically coupled to each of the first windings, and the second windings are connected in a closed in-phase loop. In another particular embodiment, at least two of the first windings are magnetically coupled to each other, thus ensuring a balance between current in each LED string. | 01-19-2012 |
20120019156 | LED STRING DRIVER WITH NON-DISSIPATIVE REACTANCE BALANCER - A solid state lighting arrangement constituted of: a power source providing a current which is discontinuous in at least one direction; a plurality of light emitting diode (LED) strings arranged to receive the provided current from the power source; and a plurality of reactance elements, each of the plurality of reactance elements arranged in series with a particular one of the plurality of LED strings, such that current flowing from the power source through each of the LED strings creates a voltage drop across the series arranged reactance element, wherein the voltage drop across each of the series arranged reactance elements responsive to the discontinuous current is at least 10 times greater than the maximum difference between the voltage drops among the plurality of LED strings. | 01-26-2012 |
20120098442 | SYNCHRONOUS REGULATION FOR LED STRING DRIVER - A light emitting diode (LED) based luminaire driving arrangement constituted of: a switched driver; a plurality of LED based luminaires arranged to receive power from the switched driver; at least one electronically controlled switch in series with at least one of the plurality of LED based luminaires and arranged to alternatively pass current through the at least one LED based luminaire when closed and prevent the flow of current through the at least one LED based luminaire when opened; and at least one synchronous driver in communication with the at least one electronically controlled switch, the at least one synchronous driver arranged to close the at least one electronically controlled switch only when the switched driver is actively supplying power. | 04-26-2012 |
20120242230 | BRIGHTNESS CONTROL FOR LED LIGHTING - A driving arrangement for light emitting diode (LED) based illumination constituted of: a comparison circuitry arranged to compare an integral of a target current over a target illumination time for at least one LED based luminaire with an integral of an illumination current over an illumination time for the at least one LED based luminaire, the comparison circuitry arranged to output a comparison signal; and a control circuitry in communication with the comparison circuitry and arranged to alternately: allow the flow of electrical current through the at least one LED based luminaire responsive to a first condition of the comparison signal; and prevent the flow of electrical current through the at least one LED based luminaire responsive to a second condition of the comparison signal, the second condition different from the first condition. | 09-27-2012 |
20120280628 | HIGH EFFICIENCY LED DRIVING METHOD - An arrangement wherein a plurality of LED strings are driven with a balanced drive signal, i.e. a drive signal wherein the positive side and negative side are of equal energy over time, is provided. In a preferred embodiment, the drive signal is balanced responsive to a capacitor provided between a switching network and a driving transformer. Balance of current between various LED strings is provided by a balancing transformer. | 11-08-2012 |
20130099670 | METHOD AND APPARATUS FOR LED STRING SHORT CIRCUIT DETECTION AND PROTECTION - An apparatus for LED string short circuit detection constituted of: a constant current drive circuit; a plurality of LED strings, a first end of each of the plurality of LED strings coupled to a common output of the constant current drive circuit; a first sense resistor coupled between a second end of each of the plurality of LED strings and a chassis; a second sense resistor coupled between the chassis and a return of the constant current drive circuit; and a comparing circuit arranged to compare the amount of current flow through the first sense resistor with amount of current flow through the second sense resistor, the comparing circuit arranged to assert a fault signal in the event that the amount of current flow through the second sense resistor exceeds the current flow through the first sense resistor by a predetermined minimum value. | 04-25-2013 |
20130106299 | HIGH EFFICIENCY LED DRIVING METHOD FOR ODD NUMBER OF LED STRINGS | 05-02-2013 |
20140285097 | SYNCHRONOUS REGULATION FOR LED STRING DRIVER - A light emitting diode (LED) based luminaire driving arrangement constituted of: a switched driver; a plurality of LED based luminaires arranged to receive power from the switched driver; at least one electronically controlled switch in series with at least one of the plurality of LED based luminaires and arranged to alternatively pass current through the at least one LED based luminaire when closed and prevent the flow of current through the at least one LED based luminaire when opened; and at least one synchronous driver in communication with the at least one electronically controlled switch, the at least one synchronous driver arranged to close the at least one electronically controlled switch only when the switched driver is actively supplying power. | 09-25-2014 |