Patents by Inventor Ronald Choi

Ronald Choi 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: 6222387
    Abstract: An I/O interface circuit which is capable of tolerating the application of an overvoltage condition to a corresponding I/O pad but which also has a relatively low trip point voltage includes an overvoltage detection circuit configured to have a trip point at a first voltage provided by a voltage divider circuit. The voltage divider circuit may include a pair of transistors coupled in series between a voltage source having a second voltage and ground. In such cases, the first voltage may be approximately equal to the difference between the second voltage and a threshold voltage of one of the pair of transistors. Alternatively, the voltage divider circuit may include a NAND gate having an output coupled to the overvoltage detection circuit and an input coupled to receive a second voltage. The second voltage may be determined by a voltage at an I/O pad of the I/O interface and one or more diodes coupled between the I/O pad and the NAND gate.
    Type: Grant
    Filed: October 26, 1998
    Date of Patent: April 24, 2001
    Assignee: Cypress Semiconductor Corporation
    Inventors: Anita X. Meng, Ronald Choi