The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 29, 1999
Filed:
Sep. 02, 1997
Hwang-Cherng Chow, Hsinchu, TW;
Abstract
In a preferred embodiment of the present invention, a bidirectional buffer connects a first device, such as a CMOS chip having a first voltage, such as VCC, to a second device having a second voltage, such as VDD, through a terminal pad. The buffer includes a bootstrap capacitor to assist in driving up the terminal pad. In particular, the buffer comprises an output and an input portion. The output portion includes a first driver for driving the terminal pad up to VDD and a second driver for driving the terminal pad down to VSS. The first driver includes a pull-up PMOS transistor and a pull-up NMOS transistor connected in series and the second driver includes a pull-down NMOS transistor. Further, preferably one pair of push-pull bootstrap control transistors are connected in parallel to the gate of the pull-up NMOS transistor for quickly driving up the first driver to a voltage level based on the bootstrap capacitor having a predetermined capacitance. The input portion includes an invertor and a protection resistor for protecting the invertor from static charges.