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:
May. 16, 2006
Filed:
Dec. 12, 2003
Sheng-hua Chen, Kaohsiung, TW;
Hung-yi Chang, Hsinchu, TW;
Jeng-huang Wu, Taipei, TW;
Faraday Technology Corp., Hsin-Chu, TW;
Abstract
An input/output buffer protection circuit, which comprises an I/O pad, an I/O buffer, an n-well control circuit, a gate control circuit, and a protection component. The I/O buffer includes a PMOS transistor and a NMOS transistor. The n-well control circuit is coupled to an n-well of the PMOS transistor. When an input voltage higher than a source voltage is applied, voltage at the n-well of the PMOS is increased by the n-well control circuit to the input voltage level. The gate control circuit is coupled to the gate terminal of the PMOS transistor and the input/output pad. When an input voltage higher than a source voltage is applied, voltage at the gate terminal of the PMOS is increased by the gate control circuit to the source voltage level. Wherein the gate control circuit comprises a transistor and the transistor transfers a high potential control voltage to the gate of the PMOS transistor in output mode. The protection component is coupled between the gate of the transistor and the I/O pad to generate a voltage drop down path and block the I/O pad signal from flowing back to the gate of the transistor.