Patents by Inventor Gyu Hyeong Cho

Gyu Hyeong Cho 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: 7710200
    Abstract: The present invention relates an output buffer and a power amplifier having the same. The output buffer includes a push-pull circuit unit, an output unit, and a driver. The push-pull circuit unit includes transistors connected to each others in a push-pull formation between a high level power voltage and a low level power voltage. The output unit is connected to the high level power voltage and the low level power voltage, and the driver drives the output unit according to a signal from the push-pull circuit unit.
    Type: Grant
    Filed: February 11, 2008
    Date of Patent: May 4, 2010
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Gyu Hyeong Cho, Tae-Woo Kwak
  • Publication number: 20100097360
    Abstract: Disclosed is a display driving apparatus. The display driving apparatus comprises: a current DAC generating a data current; a data line connected to a pixel circuit requiring data writing on a matrix array of a display panel; an adjacent data line located adjacent to the data line; a current mirror feedbacking an excessive charging current generating due to parasitic capacitance of the adjacent data line as a charging current for charging parasitic capacitance of the data line; a current output unit connected to the current mirror and including a first driving transistor unit for driving the data line, and a second driving transistor unit for driving the adjacent data line; a source follower driving the current output unit according to an output node voltage of the current DAC; and a first constant current source discharging parasitic capacitance excessively charged in the data line and the adjacent data line.
    Type: Application
    Filed: October 13, 2009
    Publication date: April 22, 2010
    Inventors: Gyu-Hyeong Cho, Yong-Joon Jeon, Jin-Yong Jeon, Seung-Chul Jung, Ki-Duk Kim, Sung-Woo Lee
  • Patent number: 7609234
    Abstract: Disclosed herein are a pixel circuit and driving method for active matrix Organic Light-emitting Diodes (OLEDs), and a display using the same. The pixel circuit includes a Voltage Control Current Source (VCCS), a high gain amplifier, a storage capacitor, and first and second switches. The VCCS is configured to drive OLEDs. The high gain amplifier is configured such that the control input signal of the VCCS causes the VCCS to be placed in an ON or OFF state. The storage capacitor is located between the input terminal of the high gain amplifier and a data line so as to assign the ON-time of the VCCS. The first and second switches are configured to be controlled through a scan line so as to store voltage in the storage capacitor and control the light-emitting time of the OLEDs, and are formed the input terminal of the high gain amplifier and the input terminal of the VCCS, respectively.
    Type: Grant
    Filed: September 22, 2005
    Date of Patent: October 27, 2009
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Gyu-Hyeong Cho, Young-Suk Son, Sang-Kyung Kim, Min-Chul Lee
  • Patent number: 7605792
    Abstract: Disclosed herein is a driving method and circuit for the automatic voltage output of an active matrix organic light emitting device, which is capable of resolving the non-uniformity of brightness between pixels.
    Type: Grant
    Filed: March 3, 2006
    Date of Patent: October 20, 2009
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Young-Suk Son, Sang-Kyung Kim, Gyu-Hyeong Cho
  • Patent number: 7515081
    Abstract: A digital-to-analog converter comprises a current supplier, a current divider dividing current supplied from the current supplier into certain amounts, an inverter outputting inverted signals of input signals and non-inverted signals, a switch controlling a flow of the current divided into the certain amounts by the current divider according to the inverted signals and the non-inverted signals, and a current output block adding up the current divided into the certain amounts according to the non-inverted signals to output an analog signal. The digital-to-analog converter can be implemented on a small chip area with desired resolution.
    Type: Grant
    Filed: May 29, 2007
    Date of Patent: April 7, 2009
    Assignee: Korea Advanced Institute of Science & Technology
    Inventors: Gyu Hyeong Cho, Yong-Joon Jeon, Young-Suk Son, Sang Kyung Kim, Jin Yong Jeon, Gun Ho Lee
  • Publication number: 20090051676
    Abstract: A driving apparatus for a display is provided. The driving apparatus for a display comprises: a digital/analog converter for receiving an input voltage lower than a source voltage used in a buffer amplifier for output driving, generating a plurality of reference voltages, and selecting a reference voltage corresponding to an M (M is a positive integer) bit data signal; and an amplifier for amplifying the reference voltage selected by the digital/analog converter. Therefore, a circuit area and power consumption of the driving apparatus for a display can be minimized.
    Type: Application
    Filed: October 31, 2007
    Publication date: February 26, 2009
    Inventors: Gyu Hyeong Cho, Hyung-Min Lee, Young-Suk Son, Yong-Joon Jeon, Jin Yong Jeon, Seung-Chui Jung
  • Publication number: 20090051575
    Abstract: A driving apparatus for a display is provided. The driving apparatus for a display comprises a reference voltage generator, a digital-to-analog converter, and an output unit. The reference voltage generator generates a plurality of reference voltages, and receives a difference value between two adjacent reference voltages and generates a plurality of sub reference voltages. The digital-to-analog converter selects one of the reference voltages and outputs the selected reference voltage as a first analog signal. The digital-to-analog converter selects one of the sub reference voltages and outputs the selected reference voltage as a second analog signal. The output unit processes, by addition or subtraction, the first and second analog signals for output.
    Type: Application
    Filed: October 31, 2007
    Publication date: February 26, 2009
    Inventors: Hyung-Min Lee, Gyu Hyeong Cho, Young-Suk Son, Yong-Joon Jeon, Jin Yong Jeon, Seung-Chul Jung
  • Publication number: 20090033423
    Abstract: The present invention relates an output buffer and a power amplifier having the same. The output buffer includes a push-pull circuit unit, an output unit, and a driver. The push-pull circuit unit includes transistors connected to each others in a push-pull formation between a high level power voltage and a low level power voltage. The output unit is connected to the high level power voltage and the low level power voltage, and the driver drives the output unit according to a signal from the push-pull circuit unit.
    Type: Application
    Filed: February 11, 2008
    Publication date: February 5, 2009
    Inventors: Gyu Hyeong Cho, Tae-Woo Kwak
  • Publication number: 20080238327
    Abstract: Disclosed herein is an Active Matrix Organic Light-Emitting-Diode (AMOLED) drive circuit using transient current feedback. The AMOLED drive circuit includes a current Digital-to-Analog Converter (DAC), a data line drive transistor, a constant current source, a variable current source, a differential amplifier, and a transient charging current control unit. The DAC generates current corresponding to input digital data. The data line drive transistor is configured such that the drain terminal thereof is connected to the output node of the current DAC. The constant current source is connected between the source terminal of the data line drive transistor and a ground. The variable current source is connected between both the output node of the current DAC and the drain terminal of the drive transistor, and a voltage source. The differential amplifier is configured to input the output voltage thereof to the gate terminal of the drive transistor.
    Type: Application
    Filed: March 30, 2007
    Publication date: October 2, 2008
    Applicant: Korea Advanced Institute of Science and Technology
    Inventors: Gyu-Hyeong Cho, Young-Suk Son, Sang-Kyung Kim, Jin-Yong Jeon, Gun-Ho Lee
  • Patent number: 7414373
    Abstract: A discharge lamp driving circuit includes an inverter, a ballast capacitor, a discharge lamp, and a lamp current detecting circuit. The inverter converts a DC voltage into an AC voltage with high frequency to output the AC voltage to an output port based on a pulse width modulation control signal. The lamp current detecting circuit outputs a first voltage signal and a second voltage signal according to a voltage across the ballast capacitor to generate a lamp current sensing voltage that is proportional to a lamp current flowing through the discharge lamp. The pulse width modulation control signal has a width varying with amplitude of the lamp current so that the lamp current may be accurately detected.
    Type: Grant
    Filed: June 8, 2007
    Date of Patent: August 19, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Gyu-Hyeong Cho, Sang-Kyung Kim, Hee-Seok Han
  • Patent number: 7388336
    Abstract: A discharge lamp driving circuit includes an inverter, a ballast capacitor, a discharge lamp, and a lamp current detecting circuit. The inverter converts a DC voltage into an AC voltage with high frequency to output the AC voltage to an output port based on a pulse width modulation control signal. The lamp current detecting circuit outputs a first voltage signal and a second voltage signal according to a voltage across the ballast capacitor to generate a lamp current sensing voltage that is proportional to a lamp current flowing through the discharge lamp. The pulse width modulation control signal has a width varying with amplitude of the lamp current so that the lamp current may be accurately detected.
    Type: Grant
    Filed: June 8, 2007
    Date of Patent: June 17, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Gyu-Hyeong Cho, Sang-Kyung Kim, Hee-Seok Han
  • Publication number: 20080122819
    Abstract: Provided are a data driving circuit of an organic light emitting display and an organic light emitting display comprising the same. The organic light emitting display comprises a reference pixel controller, a data driver, and a display panel. The reference pixel controller comprises a light detector for detecting an amount of light emission of a reference pixel and outputting a first control signal thereof and a reference current controller for outputting a second control signal controlling an amount of a reference current according to the first control signal. The data driver comprises a current source for outputting a current having the same amount as the reference current according to the second control signal and a digital-analog converter for outputting a data current by scaling the current having the same amount as the reference signal to be proportioned to a data signal.
    Type: Application
    Filed: November 27, 2007
    Publication date: May 29, 2008
    Inventors: Gyu Hyeong Cho, Yong-Joon Jeon, Young-Suk Son, Jin Yong Jeon, Gun Ho Lee
  • Patent number: 7358811
    Abstract: Provided is a complementary metal oxide semiconductor variable gain amplifier controlling a dB linear gain and a method of controlling the dB linear gain. The complimentary metal oxide semiconductor variable gain amplifier includes: first through fourth transistors differentially receiving first and second input voltages and amplifying the first and second input voltage using a predetermined gain; fifth and sixth transistors controlling a transconductance according to a control voltage to control the predetermined gain; and first and second resistors generating an output voltage having the predetermined gain according to an output current generated by the fifth and sixth transistors.
    Type: Grant
    Filed: January 26, 2006
    Date of Patent: April 15, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jeongwook Koh, Hoon-tae Kim, Kyoung-sik Seol, Gyu-hyeong Cho
  • Patent number: 7339511
    Abstract: Disclosed herein are a time division sampling digital to analog converter for a flat panel display, a method of implementing the digital to analog converter, and a data driver circuit using the digital to analog converter.
    Type: Grant
    Filed: March 3, 2006
    Date of Patent: March 4, 2008
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Young-Suk Son, Sang-Kyung Kim, Gyu-Hyeong Cho
  • Publication number: 20070290911
    Abstract: A digital-to-analog converter comprises a current supplier, a current divider dividing current supplied from the current supplier into certain amounts, an inverter outputting inverted signals of input signals and non-inverted signals, a switch controlling a flow of the current divided into the certain amounts by the current divider according to the inverted signals and the non-inverted signals, and a current output block adding up the current divided into the certain amounts according to the non-inverted signals to output an analog signal. The digital-to-analog converter can be implemented on a small chip area with desired resolution.
    Type: Application
    Filed: May 29, 2007
    Publication date: December 20, 2007
    Inventors: Gyu Hyeong Cho, Yong-Joon Jeon, Young-Suk Son, Sang Kyung Kim, Jin Yong Jeon, Gun Ho Lee
  • Patent number: 7283077
    Abstract: Disclosed herein is a divide-add circuit and a high-resolution Digital-to-Analog Converter (DAC) using the same. The DAC includes a plurality of DAC units and one or more divide-add circuit units. The plurality of DAC units performs Digital-Analog (DA) conversion on two or more segmented codes, into which an input digital code is segmented. The one or more divide-add circuit units is configured to be each composed only of capacitors and switches and to generate a final DA conversion output for the entire input digital code based on the voltages of the DAC units. Accordingly, a high resolution of more than ten bits can be implemented.
    Type: Grant
    Filed: April 6, 2006
    Date of Patent: October 16, 2007
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Gyu-Hyeong Cho, Sang-Kyung Kim, Young-Suk Son
  • Publication number: 20070229084
    Abstract: A discharge lamp driving circuit includes an inverter, a ballast capacitor, a discharge lamp, and a lamp current detecting circuit. The inverter converts a DC voltage into an AC voltage with high frequency to output the AC voltage to an output port based on a pulse width modulation control signal. The lamp current detecting circuit outputs a first voltage signal and a second voltage signal according to a voltage across the ballast capacitor to generate a lamp current sensing voltage that is proportional to a lamp current flowing through the discharge lamp. The pulse width modulation control signal has a width varying with amplitude of the lamp current so that the lamp current may be accurately detected.
    Type: Application
    Filed: June 8, 2007
    Publication date: October 4, 2007
    Inventors: Gyu-Hyeong Cho, Sang-Kyung Kim, Hee-Seok Han
  • Publication number: 20070229002
    Abstract: A discharge lamp driving circuit includes an inverter, a ballast capacitor, a discharge lamp, and a lamp current detecting circuit. The inverter converts a DC voltage into an AC voltage with high frequency to output the AC voltage to an output port based on a pulse width modulation control signal. The lamp current detecting circuit outputs a first voltage signal and a second voltage signal according to a voltage across the ballast capacitor to generate a lamp current sensing voltage that is proportional to a lamp current flowing through the discharge lamp. The pulse width modulation control signal has a width varying with amplitude of the lamp current so that the lamp current may be accurately detected.
    Type: Application
    Filed: June 8, 2007
    Publication date: October 4, 2007
    Inventors: Gyu-Hyeong Cho, Sang-Kyung Kim, Hee-Seok Han
  • Patent number: 7242155
    Abstract: A discharge lamp driving circuit includes an inverter, a ballast capacitor, a discharge lamp, and a lamp current detecting circuit. The inverter converts a DC voltage into an AC voltage with high frequency to output the AC voltage to an output port based on a pulse width modulation control signal. The lamp current detecting circuit outputs a first voltage signal and a second voltage signal according to a voltage across the ballast capacitor to generate a lamp current sensing voltage that is proportional to a lamp current flowing through the discharge lamp. The pulse width modulation control signal has a width varying with amplitude of the lamp current so that the lamp current may be accurately detected.
    Type: Grant
    Filed: September 21, 2005
    Date of Patent: July 10, 2007
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Gyu-Hyeong Cho, Sang-Kyung Kim, Hee-Seok Han
  • Publication number: 20070075939
    Abstract: An active matrix organic light emitting diode AMOLED driving circuit using current feedback that ensures the uniformity of brightness in pixels of a flat panel display and shortens the time required to input accurate current to respective pixels in the driving circuit. The prevent invention provides an AMOLED driving circuit using current feedback, comprising: a current digital-to-analog converter outputting a current corresponding to input digital data; a first differential amplifier connected to the current digital-to-analog converter and controlling the input data current and a driving current of a driving transistor of a pixel circuit to be identical to each other; a current mirror mirroring driving current of an organic light emitting diode of the pixel circuit to an input side of the first differential amplifier; and a second differential amplifier coupled to the current mirror and controlling charge and discharge speeds of parasitic capacitance of the pixel circuit.
    Type: Application
    Filed: October 4, 2006
    Publication date: April 5, 2007
    Inventors: Gyu-hyeong Cho, Jin-yong Jeon, Gun-ho Lee, Young-suk Son, Sang Kim