Patents Assigned to Monolithic Power Systems
  • 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
  • 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
  • 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
  • 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
  • METHOD AND SYSTEM FOR OPEN LAMP PROTECTION
    Publication number: 20080258651
    Abstract: 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.
    Type: Application
    Filed: June 24, 2008
    Publication date: October 23, 2008
    Applicant: Monolithic Power Systems, Inc.
    Inventors: Yuancheng Ren, Kaiwei Yao, Wei Chen
  • Current balancing technique with magnetic integration for fluorescent lamps
    Patent number: 7439685
    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 6, 2005
    Date of Patent: October 21, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Sangsun Kim, Wei Chen
  • Constant-peak-current minimum-off-time pulse frequency modulator for switching regulators
    Patent number: 7439720
    Abstract: Methods and apparatus are disclosed for controlling switching regulators to automatically switch from a traditional pulse-width modulation (PWM) mode, when the load current is higher than a predetermined value, to a pulse-frequency modulation (PFM) mode, when the load current drops to a point lower than the predetermine value. Switching modes increases the efficiency of the regulator when the load current is low without provoking a large output voltage transient. In some embodiments, a single switching cycle regulates the output in the PFM mode, which reduces the switching losses and enhances the efficiency of the regulator.
    Type: Grant
    Filed: August 25, 2006
    Date of Patent: October 21, 2008
    Assignee: Monolithic Power Systems
    Inventors: James H. Nguyen, Thomas T. Chiang, Christopher T. Falvey
  • Lamp voltage feedback system and method for open lamp protection and shorted lamp protection
    Patent number: 7423384
    Abstract: 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 lamp condition occurs and a shorted lamp protection when shorted lamp condition occurs.
    Type: Grant
    Filed: November 8, 2005
    Date of Patent: September 9, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Yuancheng Ren, Kaiwei Yao, Wei Chen
  • Fixed lamp frequency synchronization with the resonant tank for discharge lamps
    Patent number: 7423388
    Abstract: 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.
    Type: Grant
    Filed: February 15, 2006
    Date of Patent: September 9, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventor: David Meng
  • Linear charger where the material temperature directly affects the circuit thermal control
    Patent number: 7420792
    Abstract: 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 is predetermined, but also the time between the start of a shutdown process and the complete shutdown is controllable.
    Type: Grant
    Filed: August 16, 2005
    Date of Patent: September 2, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Zhengwei Zhang
  • System and method for open lamp protection
    Patent number: 7420337
    Abstract: 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.
    Type: Grant
    Filed: May 31, 2006
    Date of Patent: September 2, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Yuancheng Ren, Peng Xu, Kaiwei Yao, Wei Chen
  • Hybrid control for discharge lamps
    Patent number: 7420829
    Abstract: Control methods and apparatus are disclosed for operating an inverter at resonant mode, where the inverter adapts its frequency to the resonant tank characteristics before a lamp is struck, and operates at fixed frequency after the lamp is struck. Disclosed embodiments combine the advantages of operation in fixed mode as well as the variable mode.
    Type: Grant
    Filed: August 25, 2005
    Date of Patent: September 2, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Kaiwei Yao, Wei Chen, David Meng
  • Method for high efficiency audio amplifier
    Patent number: 7417503
    Abstract: 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.
    Type: Grant
    Filed: October 17, 2005
    Date of Patent: August 26, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Peng Xu, Wei Chen, James C. Moyer