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:
Oct. 02, 2012
Filed:
Dec. 12, 2007
Andrew J. Walker, Mountain View, CA (US);
Helmut Puchner, Santa Clara, CA (US);
Andrew J. Walker, Mountain View, CA (US);
Helmut Puchner, Santa Clara, CA (US);
Cypress Semiconductor Corporation, San Jose, CA (US);
Abstract
A voltage protection device and method is provided to prevent accidental triggering of an silicon-controlled rectifier (SCR) unless the electrostatic discharge (ESD) is at a predefined threshold above the normal power supply operating voltage or below the ground supply operating voltage. The holding voltage upon the SCR is maintained above the threshold voltage to prevent accidental triggering. The present SCR avoids use of an additional field effect transistor (FET), and avoids relying upon the breakdown of the drain terminal of the FET, but instead programs the amount of holding voltage needed above the power supply voltage using mask-programmability, fuses, or other means for maintaining the holding voltage to a desired range above the power supply voltage. The programmed holding voltage is implemented using a barrier region between the PNP and the NPN of the PNPN junctions of the SCR. In addition to or as an alternative to the barrier region, hole sink junctions can be implemented close to the anode to reduce the substrate resistance in the vicinity of the anode and, therefore, extract holes from their normal target destination.