Patents by Inventor Jing-Meng Liu

Jing-Meng Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Single-chip common-drain JFET device and its applications
    Patent number: 7838902
    Abstract: A single-chip common-drain JFET device comprises a drain, two gates and two source arranged such that two common-drain JFETs are formed therewith. Due to the two JFETs merged within a single chip, no wire bonding connection is needed therebetween, thereby without parasitic inductance and resistance caused by bonding wire, and therefore improving the performance and reducing the package cost. The single-chip common-drain JFET device may be applied in buck converter, boost converter, inverting converter, switch, and two-step DC-to-DC converter to improve their performance and efficiency. Alternative single-chip common-drain JFET devices are also provided for current sense or proportional current generation.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: November 23, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Liang-Pin Tai, Jing-Meng Liu, Hung-Der Su
  • Single-chip common-drain JFET device and its applications
    Patent number: 7838900
    Abstract: A single-chip common-drain JFET device comprises a Drain, two gates and two source arranged such that two common-drain JFETs are formed therewith. Due to the two JFETs merged within a single chip, no wire bonding connection is needed therebetween, thereby without parasitic inductance and resistance caused by bonding wire, and therefore improving the performance and reducing the package cost. The single-chip common-drain JFET device may be applied in buck converter, boost converter, inverting converter, switch, and two-step DC-to-DC converter to improve their performance and efficiency. Alternative single-chip common-drain JFET devices are also provided for current sense or proportional current generation.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: November 23, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Liang-Pin Tai, Jing-Meng Liu, Hung-Der Su
  • Single-chip common-drain JFET device and its applications
    Patent number: 7838901
    Abstract: A single-chip common-drain JFET device comprises a drain, two gates and two source arranged such that two common-drain JFETs are formed therewith. Due to the two JFETs merged within a single chip, no wire bonding connection is needed therebetween, thereby without parasitic inductance and resistance caused by bonding wire, and therefore improving the performance and reducing the package cost. The single-chip common-drain JFET device may be applied in buck converter, boost converter, inverting converter, switch, and two-step DC-to-DC converter to improve their performance and efficiency. Alternative single-chip common-drain JFET devices are also provided for current sense or proportional current generation.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: November 23, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Liang-Pin Tai, Jing-Meng Liu, Hung-Der Su
  • Circuit and method for short circuit protection
    Patent number: 7808756
    Abstract: The present invention discloses a short circuit protection circuit comprising: a first input terminal; a second input terminal; an output terminal; at least two transistors including a first and a second transistors connected in series with each other and electrically connected between the first input terminal and the output terminal; and a voltage source circuit electrically connected with the first input terminal, the second input terminal, the output terminal, and the gates of the first and second transistors.
    Type: Grant
    Filed: February 6, 2008
    Date of Patent: October 5, 2010
    Assignee: Richtek Technology Corporation
    Inventor: Jing-Meng Liu
  • Power management apparatus having an extended safe operation region and operation method thereof
    Patent number: 7795855
    Abstract: Two step driving technique is used to turn on the power switch of a power management apparatus in such a manner that the power switch is weakly turned on first and then goes into a low ON-resistance region. The power switch is so avoided to operate at highest gate and drain voltages simultaneously even a non-uniform turn on happens, and is thereby away from avalanche breakdown. The safe operation region of the power management apparatus is therefore extended with minimum efficiency degradation.
    Type: Grant
    Filed: July 16, 2007
    Date of Patent: September 14, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Hung-Der Su, Jing-Meng Liu
  • LED Driver with Direct AC-DC Conversion and Control, and Method and Integrated Circuit Therefor
    Publication number: 20100225249
    Abstract: The present invention discloses an LED driver with direct AC-DC conversion and control function, and a method and integrated circuit therefor. The LED driver comprises: a primary side circuit receiving rectified AC power, the primary side circuit including at least one power switch; a transformer coupled to the primary side circuit and controlled by the at least one power switch to convert a primary voltage to a secondary voltage which is supplied to an LED circuit; and a secondary side circuit coupled to the transformer, the secondary side circuit directly controlling current flowing through the LED circuit and sending a feedback signal to the primary side circuit to control the at least one power switch thereby.
    Type: Application
    Filed: February 24, 2010
    Publication date: September 9, 2010
    Inventors: Chia-Wei Liao, Jing-Meng Liu, Roland Van Roy
  • Circuit and Method for Matching Current Channels
    Publication number: 20100225237
    Abstract: The present invention discloses a current-matching method comprising steps of: providing a plurality of current channels; grouping the plurality of current channels into W sets, each of which has Q channels; and matching the channels of the same set in current, where both W and Q are integers greater than or equal to 2.
    Type: Application
    Filed: May 18, 2010
    Publication date: September 9, 2010
    Inventor: Jing-Meng Liu
  • Analog Photovoltaic Power Circuit
    Publication number: 20100206353
    Abstract: The present invention discloses an analog photovoltaic power circuit, comprising: a photovoltaic device group for receiving photo energy to generate an input voltage; a power stage circuit for converting the input voltage to an output voltage; an optimum voltage estimation circuit for receiving a predetermined voltage and estimating an optimum voltage according to a direction of variation of the input voltage and a direction of variation of the power generated by the photovoltaic device group; and an analog comparison and control circuit for comparing the optimum voltage with the input voltage, to thereby control the operation of the power stage circuit.
    Type: Application
    Filed: April 29, 2010
    Publication date: August 19, 2010
    Inventor: Jing-Meng Liu
  • Analog Photovoltaic Power Circuit
    Publication number: 20100207451
    Abstract: The present invention discloses an analog photovoltaic power circuit, comprising: a photovoltaic device group for receiving photo energy to generate an input voltage; a power stage circuit for converting the input voltage to an output voltage; an optimum voltage estimation circuit for receiving a predetermined voltage and estimating an optimum voltage according to a direction of variation of the input voltage and a direction of variation of the power generated by the photovoltaic device group; and an analog comparison and control circuit for comparing the optimum voltage with the input voltage, to thereby control the operation of the power stage circuit.
    Type: Application
    Filed: April 29, 2010
    Publication date: August 19, 2010
    Inventor: Jing-Meng Liu
  • Single-chip common-drain JFET device and its applications
    Patent number: 7768033
    Abstract: A single-chip common-drain JFET device comprises a drain, two gates and two source arranged such that two common-drain JFETs are formed therewith. Due to the two JFETs merged within a single chip, no wire bonding connection is needed therebetween, thereby without parasitic inductance and resistance caused by bonding wire, and therefore improving the performance and reducing the package cost. The single-chip common-drain JFET device may be applied in buck converter, boost converter, inverting converter, switch, and two-step DC-to-DC converter to improve their performance and efficiency. Alternative single-chip common-drain JFET devices are also provided for current sense or proportional current generation.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: August 3, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Liang-Pin Tai, Jing-Meng Liu, Hung-Der Su
  • Single-chip common-drain JFET device and its applications
    Patent number: 7759695
    Abstract: A single-chip common-drain JFET device comprises a drain, two gates and two source arranged such that two common-drain JFETs are formed therewith. Due to the two JFETs merged within a single chip, no wire bonding connection is needed therebetween, thereby without parasitic inductance and resistance caused by bonding wire, and therefore improving the performance and reducing the package cost. The single-chip common-drain JFET device may be applied in buck converter, boost converter, inverting converter, switch, and two-step DC-to-DC converter to improve their performance and efficiency. Alternative single-chip common-drain JFET devices are also provided for current sense or proportional current generation.
    Type: Grant
    Filed: April 17, 2009
    Date of Patent: July 20, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Liang-Pin Tai, Jing-Meng Liu, Hung-Der Su
  • Pulse width modulation regulator system with automatically switching pulse skipping mode
    Patent number: 7751471
    Abstract: A pulse width modulation (PWM) Regulator System with automatically switching pulse skipping mode (PSM) is disclosed. The PWM regulator system comprises a PWM regulator, a PSM switching module and a pulse generator. The PWM regulator converts the input voltage by PWM. The PSM switching module determines to enter or exit the PSM. The pulse generator adaptively produces pulse signal for the switching regulator to operate in PSM.
    Type: Grant
    Filed: January 6, 2009
    Date of Patent: July 6, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Kwan-Jen Chu, Chung-Lung Pai, Po-Shun Chung, Jing-Meng Liu
  • LED CONTROL CIRCUIT AND METHOD
    Publication number: 20100164394
    Abstract: A LED control circuit and method determine the frequency and duty of a LED driving signal according to a swing control signal and a dimming control signal, respectively. Responsive to the swing control signal, a pulse edge generator generates a clock whose frequency is determined by the swing control signal. Responsive to the clock and the dimming control signal, a duty ratio controller generates the LED driving signal whose frequency is determined by the clock frequency and whose duty is determined by the dimming control signal.
    Type: Application
    Filed: March 11, 2010
    Publication date: July 1, 2010
    Applicant: RICHTEK TECHNOLOGY CORP.
    Inventor: JING-MENG LIU
  • Multi-output Switching regulator and control method therefor
    Publication number: 20100164282
    Abstract: The present invention discloses a multi-output switching regulator, comprising: a single-input-multiple-output voltage converter converting an input voltage to a first output voltage at a first node and a second output voltage at a second node; an input capacitor connected with the input voltage at an input node; a first output capacitor having two ends, one of which is connected with the first node; and a second output capacitor having two ends, one of which is connected with the second node; wherein the other end of the first output capacitor is connected to ground, the input node or the second node, and the other end of the second output capacitor is connected to ground, the input node or the first node.
    Type: Application
    Filed: December 2, 2009
    Publication date: July 1, 2010
    Inventors: Ching-Jung Tseng, Jui-Li Lan, Jing-Meng Liu
  • Pulse width modulation regulator system with automatically switching pulse skipping mode
    Patent number: 7746926
    Abstract: A pulse width modulation (PWM) Regulator System with automatically switching pulse skipping mode (PSM) is disclosed. The PWM regulator system comprises a PWM regulator, a PSM switching module and a pulse generator. The PWM regulator converts the input voltage by PWM. The PSM switching module determines to enter or exit the PSM. The pulse generator adaptively produces pulse signal for the switching regulator to operate in PSM.
    Type: Grant
    Filed: November 15, 2005
    Date of Patent: June 29, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Kwan-Jen Chu, Chung-Lung Pai, Po-Shun Chung, Jing-Meng Liu
  • LED driver using a depletion mode transistor to serve as a current source
    Patent number: 7728529
    Abstract: In a LED driver using a depletion mode transistor to serve as a current source, the depletion mode transistor is self-biased for providing a driving current to drive at least one LED, thereby requesting no additional control circuit to control the depletion mode transistor. The driving current is independent on the supply voltage coupled to the at least one LED, thereby requesting no additional voltage regulator, reducing the circuit size, and lowering the cost.
    Type: Grant
    Filed: June 10, 2005
    Date of Patent: June 1, 2010
    Assignee: Richtek Technology Corporation, R.O.C.
    Inventors: Jing-Meng Liu, Chung-Lung Pai, Hung-Der Su
  • Dimming Control Circuit
    Publication number: 20100084991
    Abstract: The present invention discloses a dimming control circuit, comprising: an input terminal for receiving an input signal; an analog and digital dimming circuit receiving the input signal, wherein the analog and digital dimming circuit provides an analog dimming function when a voltage level of the input signal is between a predetermined lower limit and a predetermined upper limit, and a digital dimming function when the voltage level of the input signal switches above and below the predetermined lower limit, and wherein the analog and digital dimming circuit generates an analog signal when the voltage level of the input signal is above the predetermined lower limit; and a power circuit for supplying an output current in correspondence to the analog signal generated by the analog and digital dimming circuit.
    Type: Application
    Filed: December 4, 2008
    Publication date: April 8, 2010
    Inventors: Jing-Meng Liu, Chiawei Liao, Leng-Nien Hsiu
  • Led bulb, light emitting device control method, and light emitting device controller circuit with dimming function adjustable by AC signal
    Publication number: 20100066266
    Abstract: The present invention discloses a light emitting device control method for adjusting the brightness of the light emitting device by an AC signal, comprising: receiving a signal having a turn ON angle and converting the signal to a DC signal; obtaining an average of the DC signal level, the average being a function of the turn ON angle; determining a reference voltage of a current source circuit according to the average of the DC signal level; and controlling a current flow through the light emitting device by the current source circuit.
    Type: Application
    Filed: September 1, 2009
    Publication date: March 18, 2010
    Inventors: Pei-Cheng Huang, Ching-Jung Tseng, Jing-Meng Liu
  • Switching regulator and control method thereof
    Publication number: 20100026256
    Abstract: A switching regulator may operate in a synchronous mode or an asynchronous mode. When the load current is higher than a threshold, the switching regulator switches a pair of serially connected high side and low side switches with a pulse width modulation signal. When the load current is lower than the threshold, the pulse width modulation signal is blocked not to switch the low side switch, the switching regulator switches only the high side switch with the pulse width modulation signal, the low side switch remains off, and a diode serially connected to the high side switch acts as a rectifier.
    Type: Application
    Filed: November 13, 2008
    Publication date: February 4, 2010
    Inventors: Jing-Meng Liu, An-Tung Chen, Fu-Shiang Lai
  • Capacitor charger with a modulated current varying with an input voltage and method thereof
    Patent number: 7656133
    Abstract: In a capacitor charger including a transformer having a primary winding connected with an input voltage and a secondary winding for transforming a primary current flowing through the primary winding to a secondary current flowing through the secondary winding, the primary current is adjusted according to a monitoring voltage varying with the input voltage, thereby prolonging the lifetime of the battery that provides the input voltage and improving the power efficiency of the battery.
    Type: Grant
    Filed: March 30, 2009
    Date of Patent: February 2, 2010
    Assignee: Richtek Technology Corp.
    Inventors: Chung-Lung Pai, Kwan-Jen Chu, Chun-Yen Huang, Jing-Meng Liu