US 11,893,146 B2
Tamper detection techniques
Venkata Niranjan Cherukuri, Bangalore (IN); Srinivasan Balakrishnan, Bangalore (IN); and Chirumamilla Lakshmana Rao, Bangalore (IN)
Assigned to Arm Limited, Cambridge (GB)
Filed by Arm Limited, Cambridge (GB)
Filed on Mar. 4, 2020, as Appl. No. 16/809,422.
Prior Publication US 2021/0279373 A1, Sep. 9, 2021
Int. Cl. G06F 21/86 (2013.01); G01R 19/00 (2006.01); G01R 19/12 (2006.01); G01R 27/04 (2006.01); G08B 21/00 (2006.01)
CPC G06F 21/86 (2013.01) [G01R 19/0038 (2013.01); G01R 19/12 (2013.01); G01R 27/04 (2013.01); G08B 21/00 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A device, comprising:
sensing circuitry that receives an input signal and provides an output signal based on sensing a resistance differential between multiple metal shield resistors; and
comparing circuitry that receives the output signal and provides an alarm signal based on detecting a tampering event associated with the resistance differential,
wherein the sensing circuitry has an operational amplifier and the multiple metal shield resistors that are configured to receive the input signal and provide the output signal based on sensing the resistance differential between the multiple metal shield resistors,
wherein the multiple metal shield resistors have a first metal shield resistor and a second metal shield resistor,
wherein the first metal shield resistor is coupled between an inverting input of the operational amplifier and ground, and
wherein the second metal shield resistor is coupled between the inverting input of the operational amplifier and an output of the operational amplifier.