Switching regulator circuit for operation as a switching device in a switching mode and a passive device in a passive mode
Granted: November 9, 2010
Patent Number:
7830128
A switching regulator circuit is provided for operation as a switching device in a switching mode and as a passive device in a passive mode. A controller is provided for operating the circuit in a switching mode and a passive mode. Additionally, a single transistor is provided for operating as a switching device in the switching mode and for further operating as a passive device in the passive mode.
DA/AC convert for driving cold cathode fluorescent lamp
Granted: November 2, 2010
Patent Number:
7825605
The present invention discloses a DC/AC converter in the backlight power supply system using cold cathode fluorescent lamp (CCFL). The DC/AC converter comprises a front end DC/DC converter, a full-bridge or half bridge inverter, and a piezoelectric transformer. Even with a wide range of input voltages, the front end DC/DC converter produces a predetermined DC voltage or a DC voltage with a predetermined small range and the cascaded inverter operates with a switching frequency close to…
Method for controlling a universal backlight inverter
Granted: November 2, 2010
Patent Number:
7825883
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.
Method and apparatus for high performance switch mode voltage regulators
Granted: October 5, 2010
Patent Number:
7808222
A circuit configuration for a high power switch-mode voltage regulator circuit is disclosed that includes an array of Metal Oxide Semiconductor (MOS) switching transistors electrically coupled to one another at their drains and sources, and a plurality of gate driver circuits. Each gate driver circuit is coupled substantially close to the gate and dedicated to driving only one MOS switching transistor.
Method and circuit for short-circuit and over-current protection in a discharge lamp system
Granted: September 28, 2010
Patent Number:
7804254
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.
Battery charger with temperature control
Granted: August 17, 2010
Patent Number:
7777454
A battery charger integrated circuit with temperature control is disclosed that includes a temperature sensor circuit and a charging current generator circuit. Upon receiving a temperature reading voltage (VDT), the temperature sensing circuit is operable to generate a second reference voltage (VREF) that is a function of the first reference voltage (VREF1). The charging current generator circuit generates and continuously adjusts a reference current (I1) and a charging current (IOUT)…
Close-loop class-D audio amplifier and control method thereof
Granted: June 1, 2010
Patent Number:
7728666
The present invention discloses a Class-D power amplifier and control method thereof. In one embodiment, the amplifier feeds back the signal at the output node to the inverting input of the comparator, and provides a high frequency triangular wave signal to the non-inverting input of the comparator. In addition, the non-inverting input of the comparator may be coupled to an offset voltage, while the inverting input of the comparator may be coupled to a fixed-frequency rectangular wave…
Method and system for open lamp protection
Granted: May 18, 2010
Patent Number:
7719206
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.
Short circuit current ratcheting in switch mode DC/DC voltage regulators
Granted: May 11, 2010
Patent Number:
7714558
In an embodiment, an apparatus is provided. The apparatus includes a high side pass device. The apparatus also includes a low side pass device coupled in series to the high side pass device. The apparatus further includes a control module coupled to the high side pass device and the low side pass device. The control module is coupled to the high side pass device and the low side pass device to control the high side pass device and the low side pass device. Additionally, the apparatus…
DC/DC voltage regulator with automatic current sensing selectability for linear and switch mode operation utilizing a single voltage reference
Granted: March 16, 2010
Patent Number:
7679350
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…
External control mode step down switching regulator
Granted: March 16, 2010
Patent Number:
7679341
A switching regulator integrated circuit (IC) is disclosed that includes a switch circuit that further includes a first switch and a second switch, a mode selector circuit controlled by external circuitry to select between a first mode and a second mode, and a control circuit. In response to a feedback signal from the switch circuit, when the first mode is selected, the control circuit toggles the first switch and the second switch ON and OFF alternately at a fixed first frequency. When…
Equalizing discharge lamp currents in circuits
Granted: February 23, 2010
Patent Number:
7667410
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…
Inverter for driving backlight devices in a large LCD panel
Granted: November 17, 2009
Patent Number:
7619371
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.
Battery charger with temperature control
Granted: October 6, 2009
Patent Number:
7598710
A battery charger integrated circuit with temperature control is disclosed that includes a temperature sensor circuit and a charging current generator circuit. Upon receiving a temperature reading voltage (VDT), the temperature sensing circuit is operable to generate a second reference voltage (VREF) that is a function of the first reference voltage (VREF1). The charging current generator circuit generates and continuously adjusts a reference current (I1) and a charging current (IOUT)…
Methods and protection schemes for driving discharge lamps in large panel applications
Granted: August 25, 2009
Patent Number:
7579787
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.
Low-power voltage reference
Granted: July 21, 2009
Patent Number:
7564225
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…
Method and apparatus for DC to AC power conversion for driving discharge lamps
Granted: July 14, 2009
Patent Number:
7560879
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 dropout linear regulator having high power supply rejection and low quiescent current
Granted: June 30, 2009
Patent Number:
7554307
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.
Audio amplifier with high power and high efficiency
Granted: May 26, 2009
Patent Number:
7538611
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…
Current balancing techniques for fluorescent lamps
Granted: April 28, 2009
Patent Number:
7525258
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).
