Capacitor power source tamper protection and reliability test

US8559262B2 · kind B2 · utility

Assignee

• Cypress Semiconductor Corporation · US

Inventors

• Srikanth R. Tiyyagura · Bengaluru, IN
• David W. Still · Phoenix, US
• Jayant Ashokkumar · Colorado Springs, US
• David G. Wright · San Diego, US

Key dates

• Filing date: Dec 29, 2011
• Grant date: Oct 15, 2013
• Expiry date: Jun 19, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R31/64
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A verification circuit for a capacitor power supply measures at least two voltages across the terminals of the capacitor at two points in time, the two points in time defining a time interval dT. A change in voltage dV over the time interval dT is determined. An operation powered by the capacitor is initiated, or not, by deriving from the time interval dT and/or the voltage change dV, a total required time or a total required voltage for completing the operation, and comparing the total required time or total required voltage to a pre-determined necessary total time or predetermined necessary total voltage, respectively (a “time interval test”).