Patents by Inventor Chien-Fu Tang

Chien-Fu Tang 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).

  • Patent number: 8723552
    Abstract: A floating gate driver circuit includes a level shifter, a pass element, a bistable circuit and a control logic circuit, to shift the voltage level of a control signal from a lower one to a higher one. The level shifter or the pass element has loads dynamically controlled by the control logic circuit to filter malfunction caused by dv/dt noise induced by a floating node.
    Type: Grant
    Filed: March 6, 2012
    Date of Patent: May 13, 2014
    Assignee: Richtek Technology Corp.
    Inventors: Pei-Kai Tseng, Chien-Fu Tang, Kuang-Feng Li, Isaac Y. Chen
  • Patent number: 8723560
    Abstract: A high voltage H-bridge driver circuit has a high voltage terminal and a floating node to be connected with a high side switch therebetween. When turning on the high side switch, a high voltage offset detection circuit detects a voltage related to the voltage at the floating node for triggering a zero voltage switching signal.
    Type: Grant
    Filed: October 31, 2012
    Date of Patent: May 13, 2014
    Assignee: Richtek Technology Corp.
    Inventors: Pei-Kai Tseng, Chien-Fu Tang, Issac Y. Chen, Jyun-Che Ho
  • Patent number: 8724349
    Abstract: An apparatus and method for output voltage calibration of a primary feedback flyback power module extract the difference between the output voltage of the power module and a target value, and according thereto, calibrate a reference voltage which is used in regulation of the output voltage, to thereby calibrate the output voltage to be the target value.
    Type: Grant
    Filed: June 30, 2011
    Date of Patent: May 13, 2014
    Assignee: Richtek Technology Corp.
    Inventors: Chien-Fu Tang, Isaac Y. Chen, Liang-Pin Tai
  • Patent number: 8717091
    Abstract: A control circuit for a power converter is disclosed, having a shared pin, a driving circuit, a current source, a sampling circuit, and a signal processing circuit. The shared pin is used for coupling with an output end of the power converter through a resistor. The driving circuit is used for conducting a switch of the power converter. The current source provides a current to the resistor through the shared pin. The sampling circuit samples the signal on the shared pin for generating a first sampling value and a second sampling value. When the difference between the first sampling value and the second sampling value is less than a predetermined value, the signal processing circuit configures the driving circuit to adjust at least one of the conduction time and the conduction frequency of the switch according to an output signal of the power converter received from the shared pin.
    Type: Grant
    Filed: March 12, 2013
    Date of Patent: May 6, 2014
    Assignee: Richtek Technology Corporation
    Inventors: Yung-Chih Lai, Isaac Y. Chen, Chien-Fu Tang, Jiun-Hung Pan
  • Publication number: 20140118029
    Abstract: A high voltage half-bridge driver circuit has a high voltage terminal and a floating node to be connected with a high side switch therebetween. When turning on the high side switch, a high voltage offset detection circuit detects a voltage related to the voltage at the floating node for triggering a zero voltage switching signal.
    Type: Application
    Filed: October 24, 2013
    Publication date: May 1, 2014
    Applicant: Richtek Technology Corp.
    Inventors: Pei-Kai TSENG, Chien-Fu TANG, Issac Y. CHEN, Jyun-Che HO
  • Patent number: 8704590
    Abstract: A control circuit for a power converter includes a shared pin, a driving circuit, a current source, a sampling circuit, and a signal processing circuit. The shared pin is coupled with an output end of the power converter through a resistor. The driving circuit conducts a switch of the power converter. The current source provides a current to the resistor through the shared pin. The sampling circuit samples the signal on the shared pin for generating a first sampling value and a second sampling value. The signal processing circuit calculates a first difference between the first sampling value and a first reference value, and a second difference between the second sampling value and a second reference value. When the difference between the first difference and the second difference is less than a predetermined value, the signal processing circuit may therefore configure the conduction time or frequency of the switch.
    Type: Grant
    Filed: September 20, 2013
    Date of Patent: April 22, 2014
    Assignee: Richtek Technology Corporation
    Inventors: Yung-Chih Lai, Isaac Y Chen, Chien-Fu Tang, Jiun-Hung Pan
  • Patent number: 8674554
    Abstract: A power off delay circuit includes a switch connected between an external power input terminal and an internal power supply terminal, a capacitor connected to the internal power supply terminal, and a hysteresis comparator to switch the switch according to the voltages of the external power input terminal and the internal power supply terminal. During on-time of the switch, the external power input terminal is connected to the internal power supply terminal and the capacitor can be charged by the external power source. When the switch is off, the capacitor provides electric power for an internal circuit. Application of the power off delay circuit to an audio system may eliminate the turn-off pops of the audio system.
    Type: Grant
    Filed: June 18, 2010
    Date of Patent: March 18, 2014
    Assignee: Richtek Technology Corp.
    Inventors: Chi-Hua Lin, Chien-Fu Tang, Isaac Y Chen, An-Tung Chen
  • Publication number: 20140056036
    Abstract: An AC-to-DC power converter with a BJT as a power switch can set a base current of the BJT by a current setting resistor which is in the outside of a control integrated circuit. Since an output current and a recovery current of the BJT are injected into a sensing resistor, the AC-to-DC power converter can correctly detect an inductor current thereof from the sensing resistor.
    Type: Application
    Filed: August 22, 2013
    Publication date: February 27, 2014
    Applicant: Richtek Technology Corporation
    Inventors: Jiun-Hung PAN, Chien-Fu TANG, Jyun-Che HO, Isaac Y. CHEN, Yu-Chang CHEN, Jung-Pei CHENG
  • Publication number: 20140042515
    Abstract: The present invention provides a high voltage device including a shielding metal layer to reduce the noise interference from a high voltage source. The high voltage device includes a substrate, a field oxide layer, a gate layer, a shielding metal layer, and a high voltage interconnection line. The substrate includes a first doped region and a second doped region separated from each other. The field oxide layer is disposed on the substrate. The gate layer is disposed above the field oxide layer. The high voltage interconnection line is coupled to the first doped region and passes above but not below the first shielding metal layer.
    Type: Application
    Filed: August 7, 2012
    Publication date: February 13, 2014
    Inventors: Pei-Kai Tseng, Chien-Fu Tang, Issac Y. Chen
  • Patent number: 8643292
    Abstract: The present invention discloses a digital dimming device and a digital dimming method, for controlling a plurality of light emitting device channels. The method comprises: generating a corresponding plurality of driving signals to control the plurality of light emitting device channels; receiving a PWM input signal having a duty ratio, and phase shifting the PWM input signal to generate multiple PWM output signals with about the same duty ratio as the PWM input signal, but with respectively shifted phases; and enabling or disabling corresponding driving signals by the multiple PWM output signals, respectively.
    Type: Grant
    Filed: October 22, 2010
    Date of Patent: February 4, 2014
    Assignee: Richtek Technology Corporation
    Inventors: Chien-Fu Tang, Isaac Chen, An-Tung Chen
  • Publication number: 20140022010
    Abstract: A control circuit for a power converter includes a shared pin, a driving circuit, a current source, a sampling circuit, and a signal processing circuit. The shared pin is coupled with an output end of the power converter through a resistor. The driving circuit conducts a switch of the power converter. The current source provides a current to the resistor through the shared pin. The sampling circuit samples the signal on the shared pin for generating a first sampling value and a second sampling value. The signal processing circuit calculates a first difference between the first sampling value and a first reference value, and a second difference between the second sampling value and a second reference value. When the difference between the first difference and the second difference is less than a predetermined value, the signal processing circuit may therefore configure the conduction time or frequency of the switch.
    Type: Application
    Filed: September 20, 2013
    Publication date: January 23, 2014
    Applicant: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Yung-Chih LAI, Isaac Y. CHEN, Chien-Fu TANG, Jiun-Hung PAN
  • Patent number: 8634212
    Abstract: A controller for a power converter is provided. The controller includes a sense current integrating circuit, a reference current integrating circuit and a drive signal generation circuit. The sense current integrating circuit performs an integrating operation to a sense current representative of a conduction current flowing through a power switch of the power converter and thereby outputs a first integrating result. The reference current integrating circuit performs another integrating operation to a reference current and thereby outputs a second integrating result. The drive signal generation circuit determines a switching period of the power switch according to a status of an output voltage of the power converter cooperative with a relative magnitude relationship between the first integrating result and the second integrating circuit. Furthermore, a controlling method for such power converter also is provided.
    Type: Grant
    Filed: March 4, 2011
    Date of Patent: January 21, 2014
    Assignee: Richtek Technology Corp
    Inventors: Chien-Fu Tang, Isaac Y. Chen, Jiun-Hung Pan
  • Publication number: 20130342127
    Abstract: An LED control device for configuring a phase-cut dimming system includes an LED and a switch. The LED control device configures the conduction status of the switch so as to supply power to the LED according to an input signal. The LED control device further detects whether the input signal is phase-cut. When the input signal is phase-cut, the LED control device stores the signal values of the internal circuits. Afterward, when the input signal is not phase-cut, the LED control device restores the stored signal values so that the internal circuits may resume to the previous operation status rapidly.
    Type: Application
    Filed: June 25, 2013
    Publication date: December 26, 2013
    Inventors: Jiun-Hung PAN, Chien-Fu TANG, Isaac Y. CHEN, Tsung-Hsi YANG
  • Publication number: 20130335038
    Abstract: A bleeding circuit and method for an electromagnetic interference filter detect whether or not an AC power source connected to the electromagnetic interference filter is removed, establish a discharge path for discharging a capacitor of the electromagnetic interference filter once the connected AC power source is removed, and cut off the discharge path during the AC power source is in connection to the electromagnetic interference filter for decreasing power consumption of the electromagnetic interference filter.
    Type: Application
    Filed: September 12, 2012
    Publication date: December 19, 2013
    Applicant: RICHTEK TECHNOLOGY CORPORATION
    Inventors: YEN-TE LEE, KUO-CHI LIU, FU-SHENG TSAI, KUANG-FENG LI, CHUNG-CHENG CHANG, JIUN-HUNG PAN, CHIEN-FU TANG, ISAAC Y. CHEN
  • Patent number: 8570020
    Abstract: A non-constant frequency voltage regulator includes a constant-time trigger to trigger a constant on-time or a constant off-time for a pulse width modulation signal, a current generator to provide a first current to determine the constant on-time or the constant off-time, a power output stage operated by the pulse width modulation signal to produce a load current, and a frequency control circuit for loading feed forward by a second current added to the first current to adjust the constant on-time or the constant off-time for frequency compensation to the pulse width modulation signal.
    Type: Grant
    Filed: November 9, 2010
    Date of Patent: October 29, 2013
    Assignee: Richtek Technology Corp.
    Inventors: Chien-Fu Tang, Isaac Y Chen
  • Publication number: 20130234790
    Abstract: A control circuit for a power converter is disclosed, having a shared pin, a driving circuit, a current source, a sampling circuit, and a signal processing circuit. The shared pin is used for coupling with an output end of the power converter through a resistor. The driving circuit is used for conducting a switch of the power converter. The current source provides a current to the resistor through the shared pin. The sampling circuit samples the signal on the shared pin for generating a first sampling value and a second sampling value. When the difference between the first sampling value and the second sampling value is less than a predetermined value, the signal processing circuit configures the driving circuit to adjust at least one of the conduction time and the conduction frequency of the switch according to an output signal of the power converter received from the shared pin.
    Type: Application
    Filed: March 12, 2013
    Publication date: September 12, 2013
    Applicant: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Yung-Chih LAI, Isaac Y. CHEN, Chien-Fu TANG, Jiun-Hung PAN
  • Publication number: 20130235633
    Abstract: A control circuit for a power converter has a current source, a sampling circuit, a signal processing circuit, a driving circuit, and a shared pin. The shared pin is used for coupling with a resistor and a switch. The current source, coupled with the shared pin, provides a current through the shared pin to the resistor in a first period. The sampling circuit, coupled with the shared pin, samples signals on the shared pin for generating a first sampling value and a second sampling value. The signal processing circuit, coupled with the sampling circuit, compares the first sampling value and the second sampling value. The driving circuit generates driving signals for conducting the switch. When the difference of the first sampling value and the second sampling value is less than a predetermined value, the signal processing circuit configures the driving circuit to intermittently conduct the switch in a second period.
    Type: Application
    Filed: March 7, 2013
    Publication date: September 12, 2013
    Applicant: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Tsung-Hsi YANG, Isaac Y. CHEN, Chien-Fu TANG, Jiun-Hung PAN
  • Publication number: 20130229207
    Abstract: A floating gate driver includes a level shifter to transmit a set signal and a reset signal to a first output terminal and a second output terminal, respectively. The level shifter includes a first high-voltage transistor, a first current limiter and a first input transistor connected in series between the first output terminal and a ground terminal, and a second high-voltage transistor, a second current limiter and a second input transistor connected in series between the second output terminal and the ground terminal, and the first and second high-voltage transistors are remained on. With this arrangement, the level shifter can transmit signals from low side to high side under better safe operating area and has better noise immunity.
    Type: Application
    Filed: February 27, 2013
    Publication date: September 5, 2013
    Applicant: RICHTEK TECHNOLOGY CORPORATION
    Inventors: Pei-Kai TSENG, Chien-Fu TANG, Isaac Y. CHEN
  • Patent number: 8508203
    Abstract: The present invention discloses a control circuit of a switching regulator wherein a confirmation signal is generated to confirm that an upper gate switch has been turned off, to avoid shoot-through. The confirmation signal is generated by obtaining an upper gate sampling signal from a transistor in a level shift circuit which receives a resetting signal for turning off the upper gate switch.
    Type: Grant
    Filed: November 10, 2010
    Date of Patent: August 13, 2013
    Assignee: Richtek Technology Corporation
    Inventors: Chien Fu Tang, Isaac Y. Chen, Pei-kai Tseng
  • Publication number: 20130070379
    Abstract: The present invention discloses a power regulator with over current protection (OCP), a control circuit thereof, and a method of over current protection. The power regulator with OCP includes: a primary circuit, a transformer, and a secondary circuit. The power regulator receives AC power, and generates secondary current which is supplied to a load circuit. The primary circuit includes a control circuit which includes: a switch control circuit, a first comparator circuit, a sample and hold circuit, and a compensation circuit which is coupled to the sample and hold circuit. The compensation circuit adaptively adjusts a threshold level of the OCP according to a current sense signal, or controls a delay time of an over current detection signal to compensate an error of the OCP threshold level, which is caused by the AC power, such that the primary current may have a peak corresponding to a predetermined setting.
    Type: Application
    Filed: September 21, 2011
    Publication date: March 21, 2013
    Inventors: Jiun-Hung Pan, Chien-Fu Tang, Isaac Y. Chen