Patents Assigned to Monolithic Power Systems, Inc.
  • External control mode step down switching regulator
    Patent number: 7679341
    Abstract: 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 a second mode is selected, the control circuit causes the second switch to turn OFF completely and the first switch to switch ON and OFF at a variable second frequency.
    Type: Grant
    Filed: December 12, 2007
    Date of Patent: March 16, 2010
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Wei Chen
  • Equalizing discharge lamp currents in circuits
    Patent number: 7667410
    Abstract: 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 (CCFLs).
    Type: Grant
    Filed: July 27, 2005
    Date of Patent: February 23, 2010
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Sangsun Kim, Wei Chen
  • Inverter for driving backlight devices in a large LCD panel
    Patent number: 7619371
    Abstract: 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.
    Type: Grant
    Filed: April 11, 2006
    Date of Patent: November 17, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Wei Chen
  • Battery charger with temperature control
    Patent number: 7598710
    Abstract: 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) according to the second reference voltage (VREF). Whenever the temperature reading voltage (VDT) exceeds the first reference voltage, the temperature sensor circuit is operable to adjust the second reference voltage (VREF).
    Type: Grant
    Filed: December 8, 2006
    Date of Patent: October 6, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Zhengwei Zhang
  • METHOD AND APPARATUS FOR SYNCHRONOUS BOOST VOLTAGE REGULATORS WITH ACTIVE NEGATIVE CURRENT MODULATION
    Publication number: 20090243568
    Abstract: A switch-mode synchronous boost voltage regulator is disclosed that includes a boost voltage regulator and an active current modulator. The active current modulator detects a negative current flowing through the high-side switch during a light load condition. When the negative current is detected, the active current modulator is operable to maintain the high-side switch “on” in a linear mode and to limit the negative current to a predetermined current level.
    Type: Application
    Filed: March 28, 2008
    Publication date: October 1, 2009
    Applicant: Monolithic Power Systems, Inc.
    Inventor: James H. Nguyen
  • Methods and protection schemes for driving discharge lamps in large panel applications
    Patent number: 7579787
    Abstract: 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.
    Type: Grant
    Filed: August 21, 2007
    Date of Patent: August 25, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Wei Chen, James C. Moyer, Paul Ueunten
  • Low-power voltage reference
    Patent number: 7564225
    Abstract: 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 different work functions.
    Type: Grant
    Filed: September 28, 2005
    Date of Patent: July 21, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Farhood Moraveji, Michael Hsing
  • Method and apparatus for DC to AC power conversion for driving discharge lamps
    Patent number: 7560879
    Abstract: 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.
    Type: Grant
    Filed: January 18, 2006
    Date of Patent: July 14, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Wei Chen
  • Low dropout linear regulator having high power supply rejection and low quiescent current
    Patent number: 7554307
    Abstract: 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.
    Type: Grant
    Filed: June 15, 2006
    Date of Patent: June 30, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Farhood Moraveji
  • METHOD AND APPARATUS FOR EXTERNAL CONTROL MODE STEP DOWN SWITCHING REGULATOR
    Publication number: 20090153127
    Abstract: 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 a second mode is selected, the control circuit causes the second switch to turn OFF completely and the first switch to switch ON and OFF at a variable second frequency.
    Type: Application
    Filed: December 12, 2007
    Publication date: June 18, 2009
    Applicant: Monolithic Power Systems, Inc.
    Inventor: Wei Chen
  • SIMPLE PROTECTION CIRCUIT AND ADAPTIVE FREQUENCY SWEEPING METHOD FOR CCFL INVERTER
    Publication number: 20090140655
    Abstract: A CCFL inverter circuit integrates a feedback circuit and protection circuit together. For both in-phase and out-of-phase applications, sensed lamp voltages can be used for open lamp and short lamp detection and sensed currents can be used for open lamp detection. The driving circuit adjusts the open lamp frequency by using a duty cycle control signal so that the driving circuit can always achieve the desired lamp voltage gain.
    Type: Application
    Filed: July 1, 2008
    Publication date: June 4, 2009
    Applicant: Monolithic Power Systems, Inc.
    Inventors: Junming Zhang, Yuancheng Ren, Kaiwei Yao, Eric Yang
  • Audio amplifier with high power and high efficiency
    Patent number: 7538611
    Abstract: 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 turn, provides good sound quality and low THD. The resulting variable switching frequencies also help to alleviate EMI problems.
    Type: Grant
    Filed: March 7, 2006
    Date of Patent: May 26, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Wei Chen, Peng Xu
  • Current balancing techniques for fluorescent lamps
    Patent number: 7525258
    Abstract: 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).
    Type: Grant
    Filed: June 14, 2006
    Date of Patent: April 28, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Sangsun Kim, Wei Chen
  • METHOD AND APPARATUS FOR HIGH PERFORMANCE SWITCH MODE VOLTAGE REGULATORS
    Publication number: 20090096511
    Abstract: 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.
    Type: Application
    Filed: October 12, 2007
    Publication date: April 16, 2009
    Applicant: Monolithic Power Systems, Inc.
    Inventor: Paul Ueunten
  • LAYOUT SCHEMES AND APPARATUS FOR HIGH PERFORMANCE DC-DC OUTPUT STAGE
    Publication number: 20090096435
    Abstract: A layout method that enables a high power switch mode voltage regulator integrated circuit to generate a large output current and achieve substantially low switching loss is disclosed. The layout method includes forming an array of switching elements on a semiconductor die, each switching element including a plurality of discrete transistors configured to have a substantially reduced ON resistance; and forming a plurality of gate driver circuits on the same die among the switching elements, all using a single metal process. Each gate driver circuit placed substantially close to and dedicated to drive only one switching element so that the gate coupling capacitance resistance product is substantially reduced.
    Type: Application
    Filed: October 12, 2007
    Publication date: April 16, 2009
    Applicant: Monolithic Power Systems, Inc.
    Inventor: Paul Ueunten
  • High-impedance level-shifting amplifier capable of handling input signals with a voltage magnitude that exceeds a supply voltage
    Patent number: 7511572
    Abstract: A level-shifting amplifier is provided for level-shifting an input signal with a voltage magnitude that exceeds a supply voltage of the amplifier. In operation, the amplifier has an input impedance of greater than 100 MOhms.
    Type: Grant
    Filed: May 6, 2008
    Date of Patent: March 31, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventor: James Copland Moyer
  • Method and apparatus for overshoot and undershoot errors correction in analog low dropout regulators
    Patent number: 7502719
    Abstract: The present invention provides a method and apparatus for dynamically correcting overshoot and undershoot errors in an analog integrated circuit by improving the reaction time (?t) of the analog integrated circuit. Equivalently, an error correction circuit is disclosed including an overshoot correction circuit and an undershoot correction circuit that are only activated to reduce overshoot and undershoot errors by increasing the bandwidth of the integrated circuit when either undershoot or overshoot errors are detected.
    Type: Grant
    Filed: January 25, 2007
    Date of Patent: March 10, 2009
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Farhood Moraveji
  • Class D audio amplifier with PWM and feedback
    Patent number: 7456685
    Abstract: 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.
    Type: Grant
    Filed: March 7, 2006
    Date of Patent: November 25, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Wei Chen
  • Method and apparatus for controlling a discharge lamp in a backlighted display
    Patent number: 7443107
    Abstract: 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 minimized by placing the load (lamp) directly across the secondary side of the transformer. When configured to regulate delivered power, the secondary side may be fully floated which practically eliminates a thermometer effect on the operation of the lamp. All of the active elements, including the power switches, may be integrated into a monolithic silicon circuit.
    Type: Grant
    Filed: August 16, 2005
    Date of Patent: October 28, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: John Robert Shannon, James Copland Moyer, Michael Ren Hsing
  • Method of 1-bit hysteretic control in N-bit A/D conversion
    Patent number: 7443330
    Abstract: The present invention introduces methods to eliminate 1-bit jitter problem in the N-bit A/D conversion applications. The methods do not require any increase in the total bit of A/D conversion.
    Type: Grant
    Filed: June 8, 2006
    Date of Patent: October 28, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Kaiwei Yao, Zhou Lu