DRIVER FOR LIGHT SOURCE HAVING INTEGRATED PHOTOSENSITIVE ELEMENTS FOR DRIVER CONTROL
Granted: January 25, 2007
Application Number:
20070018941
A method for automatically adjusting the intensity of a lighting element based on feedback from internal and external sources of light is disclosed herein. A photosensitive element senses ambient light and transmits an electrical signal proportional to the intensity of the ambient light to a driver. The driver automatically adjusts the intensity of the lighting element based on this feedback to provide optimal conditions for the application. In addition, the lighting element transmits an…
Current balancing technique with magnetic integration for fluorescent lamps
Granted: January 11, 2007
Application Number:
20070007908
Methods and apparatus are disclosed for balancing currents passing through multiple parallel circuit branches and in some cases through parallel fluorescent lamps. Single transformers with multiple-leg magnetic cores are wound in specific manners that simplify current balancing. Conventional three-legged EE-type magnetic cores, with disclosed windings are used to balance current in circuits with three or more parallel branches, such as parallel connected Cold Cathode Fluorescent Lamps…
Equalizing discharge lamp currents in circuits
Granted: January 11, 2007
Application Number:
20070007909
Methods and apparatus are disclosed for balancing currents passing through multiple parallel circuit branches and in some cases through parallel fluorescent lamps. Single transformers with multiple-leg magnetic cores are wound in specific manners that simplify current balancing. Conventional three-legged EE-type magnetic cores, with disclosed windings are used to balance current in circuits with three or more parallel branches, such as parallel connected Cold Cathode Fluorescent Lamps…
Current balancing techniques for fluorescent lamps
Granted: January 11, 2007
Application Number:
20070007910
Methods and apparatus are disclosed for balancing currents passing through multiple circuit loads and in some cases through fluorescent lamps. Multiple-leg magnetic cores are wound in specific manners to simplify current balancing. Conventional three- or more than three-legged EE- and EI-type magnetic cores, with disclosed windings are used to balance current in circuits with multiple branches, such as connected Cold Cathode Fluorescent Lamps (CCFLs).
Audio amplifier with high power and high efficiency
Granted: September 7, 2006
Application Number:
20060197596
A Class D audio amplifier with output signals capable of being as high as the amplifier's supply voltage. The audio amplifier contains a comparator, a positive output stage, and a negative output stage. The output signal from the positive output stage and the output signal from the negative output stage have opposite polarities and are connected to the comparator's negative and positive input terminals respectively. The Class D audio amplifier has superior transient response, and in…
Active damping control for a switch mode power supply
Granted: July 20, 2006
Application Number:
20060158127
Methods and apparatus are disclosed for suppressing circuit noise due to parasitic elements in switch mode power supplies. The presented embodiments use actively controlled damping devices such as controllable resistors, current sources, and tri-state power devices to achieve required damping and to minimize power loss.
Method and apparatus for DC to AC power conversion for driving discharge lamps
Granted: July 20, 2006
Application Number:
20060158136
Methods and circuits are disclosed for converting DC power to AC power for driving discharge lamps such as cold cathode fluorescent lamps (CCFLs). Among other advantages, the lamp current and open lamp voltage can be regulated by a simple control scheme.
Low noise audio amplifier
Granted: May 25, 2006
Application Number:
20060109049
An amplifier circuit performs audio signal processing and other signal processing by using a noise reduction feedback network. The noise reduction feedback network turns on automatically when output signals are in or near voltage saturation state. The network provides feedback signals to the input terminals of the amplifier's control stage and modulates the control signals. It prevents audio frequency noise associated with “clipping”.
Method for high efficiency audio amplifier
Granted: April 20, 2006
Application Number:
20060082414
The present invention introduces methods and circuits to amplify audio signals for driving speakers. An additional feedback circuit is added in an audio amplifier to couple the amplifier stage and output stage of the audio amplifier. The feedback circuit turned off as long as output voltages of the audio amplifier are not near saturation. The feedback circuit is turned on to reduce audible noises if output voltages of the audio amplifier are near saturation.
Methods and protection schemes for driving discharge lamps in large panel applications
Granted: April 13, 2006
Application Number:
20060076900
The present disclosure introduces a simple method and apparatus for converting DC power to AC power for driving discharge lamps such as a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), or a flat fluorescent lamp (FFL). Among other advantages, the invention allows the proper protection under short circuit conditions for applications where the normal lamp current is greater than safe current limit.
Fixed operating frequency inverter for cold cathode fluorescent lamp having strike frequency adjusted by voltage to current phase relationship
Granted: June 30, 2005
Application Number:
20050140313
A method of driving a lamp that uses a DC to AC inverter that is connected to a primary winding of a transformer is disclosed. The inverter frequency is variable, and in one embodiment, may be controlled by a voltage controlled oscillator. Circuitry is included that monitors the phase relationship between a voltage across a secondary of the transformer and a current through the primary of the transformer. The circuitry monitors the phase relationship and adjusts the inverter frequency,…
Method and apparatus for controlling a discharge lamp in a backlighted display
Granted: August 28, 2003
Application Number:
20030161164
The described DC to AC inverter efficiently controls the amount of electrical power used to drive a cold cathode fluorescent lamp (CCFL). The output is a fairly pure sine wave which is proportional to an input control voltage. The output waveform purity is ensured by driving a symmetrical rectangular waveform into a second-order, low pass filter at the resonant frequency of the filter for all conditions of line voltage and delivered power. Operating stress on the step-up transformer is…
