Patents by Inventor Sang-Hoon Chai

Sang-Hoon Chai 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: 6094103
    Abstract: Disclosed is a multiple feedback loop ring oscillator and delay cell with high oscillation voltage. It is an object of the present invention to implement a new ring oscillator for the VCO of a high speed PLL and a proper delay cell with a high speed and low noise. The apparatus is composed of multiple feedback loop ring oscillator that 4 delay cells which have the first main input stage, the second main input stage, the first subsidiary input stage, the second subsidiary input stage, the third subsidiary input stage, the forth subsidiary input stage, the first output stage and the second output stage is connected to the main loop and subsidiary loop. The present invention has advantages that it can be operated in high speed, it has a low power sensitivity, there is no power noise because there is no variation of a supply current and it can improve noise characteristics.
    Type: Grant
    Filed: June 18, 1998
    Date of Patent: July 25, 2000
    Assignees: Electronics and Telecommunications Research Institute, Korea Telecom
    Inventors: Dong Youl Jeong, Gyu Hyung Cho, Sang Hoon Chai, Won Chul Song, Kyung Soo Kim
  • Patent number: 5886552
    Abstract: An improved data retiming circuit which is capable of more effectively retiming an externally inputted data by using a plurality of clocks from a voltage controlled oscillator of a phase-locked loop.
    Type: Grant
    Filed: May 20, 1997
    Date of Patent: March 23, 1999
    Assignees: Electronics And Telecommunications Research Institute, Korea Telecom
    Inventors: Sang-Hoon Chai, Hee-Bum Jung, Won-Chul Song
  • Patent number: 5656955
    Abstract: A low power output buffer circuit for outputting an Emitter Coupled Logic(ECL) signal or Pseudo ECL(PECL) signal using a CMOS device is disclosed. The prior art differential output buffer circuit is comprised of two independent output buffer circuits and each output buffer circuit utilizes 50 ohms of the load resistors, having 20 mW of current to be applied to the circuit, which requires 100 mW of total consumptive power to operate the entire circuit. According to the present invention, a simplified output buffer circuit can be constructed by connecting 100 ohms of load resistors having a center tap to ground to two pads, which reduces half of the consumptive power as compared to that in the prior art circuit.
    Type: Grant
    Filed: November 13, 1995
    Date of Patent: August 12, 1997
    Assignees: Electronics and Telecommunications Research Institute, Korea Telecommunication Authority
    Inventors: Sang-Hoon Chai, Won-Chul Song, Hoon-Bock Lee, Chang-Sik Yu, Won-Chan Kim
  • Patent number: 5483180
    Abstract: Disclosed is a data and clock recovery circuit possible to restore data signals and synchronizing clocks which have been distorted during transmission over the communication line, which is comprised of the following: main oscillation loop that maintains operating frequency by using the input data and a self oscillation loop that operates using reference clock embedded within multiplex communication devices when communication lines get shorted or when power is restored after an outage; loop selecting switch which selects the main oscillation loop during normal operating mode and selects the self oscillation loop when communication line shorts or when the power is being restored; data signal monitor which connects to the loop selecting switch and determines communication line shorting by monitoring data transmission; power supply monitor which connects to the loop selecting switch and monitors the restoration of power after an outage.
    Type: Grant
    Filed: November 22, 1994
    Date of Patent: January 9, 1996
    Inventors: Sang-Hoon Chai, Mun-Yang Park, Myung-Shin Kwak, Hae-Wook Choi
  • Patent number: 4686762
    Abstract: A method for making a semiconductor device having transistors comprising the active regions which are protected by polysilicon layer during the whole process from damages due to the other processing, that is dry etching, etc. and a minimized base region so as to provide a high operating speed and a minimium size thereof as well as lowest power consumption features.
    Type: Grant
    Filed: July 23, 1986
    Date of Patent: August 18, 1987
    Assignee: Electronics and Telecommunication Research Institute
    Inventors: Sang-Hoon Chai, Jin-Hyo Lee