Patents Assigned to Monolithic Power Systems
  • Publication number: 20080180071
    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 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: Application
    Filed: January 25, 2007
    Publication date: July 31, 2008
    Applicant: Monolithic Power Systems, Inc.
    Inventor: Farhood Moraveji
  • Publication number: 20080174251
    Abstract: An inverter comprising a low-side switching element in series with a first primary winding; a high-side switching element in series with a second primary winding, where the combination of the low-side switching element and first primary winding is connected in parallel with the combination of the high-side switching element and the second primary winding; and a clamping capacitor having one terminal connected to the first primary winding and having a second terminal connected to the second primary winding. Other embodiments are described and claimed.
    Type: Application
    Filed: February 25, 2008
    Publication date: July 24, 2008
    Applicant: Monolithic Power Systems, Inc.
    Inventors: Wei Chen, Yuancheng Ren, Junming Zhang, Lei Du
  • Publication number: 20080158760
    Abstract: 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 circuit pass the reference current and the replica current to the comparator circuit respectively.
    Type: Application
    Filed: March 17, 2008
    Publication date: July 3, 2008
    Applicant: Monolithic Power Systems, Inc.
    Inventors: James C. Moyer, Paul Ueunten
  • Patent number: 7394203
    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: Grant
    Filed: December 15, 2005
    Date of Patent: July 1, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Yuancheng Ren, Kaiwei Yao, Wei Chen
  • Publication number: 20080136377
    Abstract: 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 value.
    Type: Application
    Filed: December 8, 2006
    Publication date: June 12, 2008
    Applicant: Monolithic Power Systems, Inc.
    Inventor: Zhengwei Zhang
  • Patent number: 7385446
    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 100M Ohms.
    Type: Grant
    Filed: June 13, 2006
    Date of Patent: June 10, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventor: James Copland Moyer
  • Publication number: 20080123730
    Abstract: 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.
    Type: Application
    Filed: October 17, 2007
    Publication date: May 29, 2008
    Applicant: Monolithic Power Systems, Inc.
    Inventor: Curtis B. Robinson
  • Patent number: 7355354
    Abstract: 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.
    Type: Grant
    Filed: February 3, 2004
    Date of Patent: April 8, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Timothy James Rust, James Copland Moyer, David Joseph Christy
  • Patent number: 7336038
    Abstract: The present disclosure introduces a simple method and apparatus for converting DC power to AC power, and, specifically, to single-ended inverter circuits for driving discharge lamps such as a Cold Cathode Fluorescent Lamp (CCFL) or an External Electrode Fluorescent Lamp (EEFL). Among other advantages, these circuits offer nearly symmetrical voltage waveform to drive discharge lamps when the duty cycle is close to 50%. They also eliminate the high current and high voltage resonant capacitor on the primary side, and reduce the voltage rating of a primary switch to twice the input voltage without the need for snubber circuits. The recommended inverters can be used to efficiently drive discharge lamps at low cost, particularly for applications with a narrow input voltage range. The lamp current can be regulated through the duty cycle modulation of the main switch.
    Type: Grant
    Filed: May 19, 2006
    Date of Patent: February 26, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Wei Chen
  • Patent number: 7323829
    Abstract: A technique is described that reduces parasitic losses in circuits used to drive current through a load. An example of a system according to the technique includes four switches in series with five pins such that one pin is connected to ground. An example of an apparatus according to the technique may include four switches in series with two switches connected to ground and to a load and two switches connected to a power source. An example of a method according to the technique involves producing a voltage waveform having three phases.
    Type: Grant
    Filed: August 16, 2005
    Date of Patent: January 29, 2008
    Assignee: Monolithic Power Systems, Inc.
    Inventors: James C. Moyer, Wei Chen
  • Publication number: 20070290665
    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: Application
    Filed: June 15, 2006
    Publication date: December 20, 2007
    Applicant: Monolithic Power Systems, Inc.
    Inventor: Farhood Moraveji
  • Publication number: 20070285033
    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: Application
    Filed: August 21, 2007
    Publication date: December 13, 2007
    Applicant: Monolithic Power Systems, Inc.
    Inventors: Wei Chen, James Moyer, Paul Ueunten
  • Publication number: 20070279024
    Abstract: 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 regulator is in operation with the switch-mode regulator (107) disabled, also maximizing the efficiency. Each regulator senses load current (131) to automatically transition between the appropriate voltage regulators at fixed load current levels. The presented invention also includes a make before break transition scheme of the voltage regulators (103) to minimize the voltage transients.
    Type: Application
    Filed: February 5, 2004
    Publication date: December 6, 2007
    Applicant: Monolithic Power Systems, Inc.
    Inventors: Christopher Falvey, Andrew Wu
  • Publication number: 20070278971
    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: Application
    Filed: May 31, 2006
    Publication date: December 6, 2007
    Applicant: Monolithic Power Systems, Inc.
    Inventors: Yuancheng Ren, Peng Xu, Kaiwei Yao, Wei Chen
  • Publication number: 20070278967
    Abstract: 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.
    Type: Application
    Filed: August 15, 2007
    Publication date: December 6, 2007
    Applicant: Monolithic Power Systems, Inc.
    Inventors: Timothy Rust, James Moyer, David Christy
  • Patent number: 7304441
    Abstract: A technique is described that facilitates sensing current through a load. A method according to the technique includes mounting a discharge lamp in a floating point configuration, sensing current through the discharge lamp, and controlling current through the discharge lamp to improve power conversion efficiency. A device constructed according to the technique may include two AC voltage sources that are out-of-phase with respect to one another. A current sense circuit may be coupled between the AC voltage sources. When a load is connected to nodes of the AC voltage sources, the current sense circuit may sense current between the nodes that is associated with, or perhaps approximates, current through the load.
    Type: Grant
    Filed: August 5, 2005
    Date of Patent: December 4, 2007
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Wei Chen, Simon Tsai
  • Patent number: 7294974
    Abstract: 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, such as by adjusting voltage controlled oscillator, so that the phase relationship is maintained at a predetermined relationship.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: November 13, 2007
    Assignee: Monolithic Power Systems, Inc.
    Inventors: James C. Moyer, Timothy J. Rust
  • Patent number: 7291991
    Abstract: 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.
    Type: Grant
    Filed: October 13, 2005
    Date of Patent: November 6, 2007
    Assignee: Monolithic Power Systems, Inc.
    Inventor: Wei Chen
  • Publication number: 20070247085
    Abstract: 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.
    Type: Application
    Filed: April 19, 2006
    Publication date: October 25, 2007
    Applicant: Monolithic Power Systems, Inc.
    Inventors: Kaiwei Yao, James Moyer, Wei Chen
  • Publication number: 20070242022
    Abstract: 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.
    Type: Application
    Filed: April 13, 2007
    Publication date: October 18, 2007
    Applicant: Monolithic Power Systems, Inc.
    Inventor: Kaiwei Yao