Patent ID: 7646208
Filing Date: 2010-01-12
Classification: G01R

Abstract:
1. A sensing circuit comprising: an on-chip sensor to detect vulnerability in a power supply of a chip comprising the on-chip sensor, said on-chip sensor detecting the vulnerability absent components external to the chip, wherein the on-chip sensor comprises a sensitive delay chain sensitive to variations in voltage of the power supply and an insensitive delay chain insensitive to variations in voltage of the power supply, the sensitive delay chain and the insensitive delay chain employed to detect the vulnerability, and wherein an output of the insensitive delay chain is a delayed signal that is coupled to an input of a first phase detector and an input of a second phase detector, and an output of the sensitive delay chain is a delayed signal that is coupled to an input of the first phase detector and an input of the second phase detector, and wherein the first phase detector and the second phase detector are used to compare the difference in phase between the delayed signals from the sensitive delay chain and the insensitive delay chain to detect vulnerability; and wherein the circuit comprises a plurality of delay chains coupled to the output of insensitive delay chain and the output of sensitive delay chain and coupled to one or more inputs of the first phase detector and one or more inputs of the second phase detector to further delay the delayed signals from the insensitive delay chain and the sensitive delay chain.