METHOD AND APPARATUS FOR FAULT DETECTION SCHEME FOR COLD CATHODE FLORESCENT LAMP (CCFL) INTEGRATED CIRCUITS
Granted: July 3, 2008
Application Number:
20080158760
A fault detection circuit and a short-circuit detection circuit for a Cold Cathode Fluorescent Lamp (CCFL) driver integrated circuit having a power bridge and a CCFL load are disclosed that includes a reference circuit operable to generate a reference current in response to an external component, a replica component having a dimension substantially less than the components of the power bridge, a multiplexer circuit, and a comparator circuit. The replica component and the multiplexer…
Battery charger with temperature control
Granted: June 12, 2008
Application Number:
20080136377
A battery charging circuit monitors the IC temperature through monitoring the charging die temperature, or directly monitoring the IC temperature using a temperature sensor. A maximum temperature allowed for the charging die is predetermined. The charging circuit is capable of reducing charging current at the predetermined maximum temperature value. The charging die signal is compared by a reference signal to achieve the reduction of charging current at the maximum allowed temperature…
SYSTEM AND METHOD FOR IMPLEMENTING A SINGLE-WIRE SERIAL PROTOCOL
Granted: May 29, 2008
Application Number:
20080123730
A method and apparatus for a single-wire serial communication includes defining a predetermined short pulse as data and a predetermined long pulse as a data separator.
Low dropout linear regulator having high power supply rejection and low quiescent current
Granted: December 20, 2007
Application Number:
20070290665
Methods and apparatus are disclosed for providing stable voltage references from within a low dropout voltage regulator. Some embodiments utilize dependable semiconductor inherent attributes to generate a voltage reference, such as a band-gap voltage reference.
METHODS AND PROTECTION SCHEMES FOR DRIVING DISCHARGE LAMPS IN LARGE PANEL APPLICATIONS
Granted: December 13, 2007
Application Number:
20070285033
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.
METHOD FOR STARTING A DISCHARGE LAMP USING HIGH ENERGY INITIAL PULSE
Granted: December 6, 2007
Application Number:
20070278967
The described DC to AC inverter efficiently controls the amount of electrical power used to drive a cold cathode fluorescent lamp (CCFL). Additionally, during striking of the CCFL, a higher energy initial energy pulse is used. During normal operation, a lower energy pulse is used.
System and method for open lamp protection
Granted: December 6, 2007
Application Number:
20070278971
A method for responding to an open lamp condition in a discharge lamp system is disclosed. The method monitors a current feedback signal flowing through a lamp and a voltage feedback signal indicative of a voltage across said lamp. A switch is used to switch between the current feedback signal to the voltage feedback signal upon detection of an open lamp condition.
Dc/Dc Voltage Regulator With Automatic Current Sensing Selectability For Linear And Swith Mode Operation Utilizing A Single Voltage Reference
Granted: December 6, 2007
Application Number:
20070279024
A switch-mode DC/DC converter (101) and linear low drop out (LIDO) DC/DC regulator (105) are connected in parallel to drive a single load Both regulators share a common voltage reference, feedback network (103), input supply and output such that the regulated voltage is identical during each mode of operation. During heavy loads the switch-mode regulator (107) is in operation and the linear regulator is disabled for the highest efficiency possible. Conversely at light loads the linear…
Method and circuit for short-circuit and over-current protection in a discharge lamp system
Granted: October 25, 2007
Application Number:
20070247085
The method and circuit of the present invention provides short-circuit detection and protection in a discharge lamp system. The transformer's primary current is sensed and used to provide short-circuit protection of the secondary winding side or high voltage side. The system and method with the present invention provides short-circuit detection and protection even when the transformer's secondary winding is shorted.
METHOD FOR CONTROLLING A UNIVERSAL BACKLIGHT INVERTER
Granted: October 18, 2007
Application Number:
20070242022
The present invention introduces methods to modify the burst frequency of an inverter in a given LCD panel without any component change on the inverter board. The present invention also introduces methods to adjust the setting of a sensing system for duty cycles and accept Display Power Saving Technology (DPST) input signals with different frequencies. The universal inverter module with the present invention can be applied for different DPST technologies.
Inverter for driving backlight devices in a large LCD panel
Granted: October 11, 2007
Application Number:
20070236153
Two out-of-phase inverters are used for driving a backlight for large LCD panels. The lamp currents of each inverter are regulated to substantially the same level to ensure the same brightness in the lamps without any current balancing devices. The switching frequencies in both inverters are synchronized and maintained in an out-of-phase condition during operation.
Class D audio amplifier with PWM and feedback
Granted: September 13, 2007
Application Number:
20070210861
The present invention introduces methods and systems to amplify digital audio signals for driving speakers. First, digital audio signals are converted to PWM audio signals by a liner PWM modulator that is open-loop. Then, PWM audio signals are amplified by a Class D audio amplifier that has at least one feedback loop.
Fixed lamp frequency synchronization with the resonant tank for discharge lamps
Granted: August 16, 2007
Application Number:
20070188106
Control methods and apparatus are disclosed for operating a full-bridge inverter at resonant frequency mode, hybrid frequency mode, and fixed frequency mode. The operating frequency of the inverter equals to the user programmed frequency if the user programmed frequency is above the resonant tank frequency; and the operating frequency is synchronized with the resonant tank frequency if the user programmed frequency is below the resonant tank frequency.
Method and system for open lamp protection
Granted: June 21, 2007
Application Number:
20070138977
A detector circuit monitors the phase relationship between the lamp voltage and the excitation voltage, and if one or more conditions are met, triggers the open lamp protection process in a discharge lamp system. The detection circuit can be incorporated into a lamp voltage feedback circuit and implemented on the integrated circuit level with less cost and circuit complexity.
Lamp voltage feedback system and method for open lamp protection and shorted lamp protection
Granted: May 10, 2007
Application Number:
20070103096
A circuit comprises a detector circuit and a protection triggering circuit in a discharge lamp system. The detector circuit detects both open lamp and shorted lamp conditions and is coupled with detecting devices, such as sensing capacitors. A DC bias is added to the sensing capacitors so that capacitor voltages are always greater than zero volts. The output voltage of the detector circuit is coupled to the protection triggering circuit, which triggers an open lamp protection when open…
Matrix inverter for driving multiple discharge lamps
Granted: April 19, 2007
Application Number:
20070085492
Methods and apparatus are disclosed for converting DC power to AC and for driving multiple discharge lamps and, more particularly, Cold Cathode Fluorescent Lamps (CCFLs), External Electrode Fluorescent Lamps (EEFLs), and Flat Fluorescent Lamps (FFLs). Disclosed methods, among other advantages, allow accurate current sharing among the lamps, minimization of the total number of power switches, and, in general, simplification of the complexity of the control system.
Switching regulator with automatic multi mode conversion
Granted: April 19, 2007
Application Number:
20070085519
Methods and apparatus are disclosed for efficient switching regulators that adapt automatically to, and operate with, input voltages that are above, below, or equal to the output voltage. The disclosed switching regulators demonstrate advantages of both buck and boost converters at high efficiency.
Low-power voltage reference
Granted: March 29, 2007
Application Number:
20070069700
A circuit provides a voltage reference using very low power. It can also be used as a shut regulator for a quiescent current as low as 1.5 ?A. It includes a transconductance amplifier, a gain stage, and a power transistor. One embodiment of this invention utilizes a work function difference between p+ gate and n+ gate to generate a predetermined reference voltage. In another embodiment of this invention, the predetermined reference voltage can be pre-adjusted using gate materials with…
Linear charger where the material temperature directly affects the circuit thermal control
Granted: March 8, 2007
Application Number:
20070052461
Methods and apparatus are disclosed for protecting circuits from damages caused by elevated temperatures. Presented embodiments illustrate IC thermal protection circuits that shut down power delivery circuits when the circuit temperature reaches a predefined upper threshold and restart the circuit when the circuit cools down to a predefined lower threshold. Other embodiments provide soft shutdown and soft restart, where not only the temperature range between the shutdown and the restart…
Isolated gate driver circuit for power switching devices
Granted: February 1, 2007
Application Number:
20070025123
Embodiments of isolated gate driver circuits are disclosed for driving high- and low-side switching devices for half- and full-bridge power converter topology. Disclosed circuits provide sufficient dead-time, operate over a wide range of duty cycles, and require a single power supply (Vcc). Typical applications for such circuits include cold cathode fluorescent lamp (CCFL) inverters that are powered by a high voltage DC rail.
