Functional and Consumption Analysis of Integrated Circuits Supplied by Inductive Power Transfer by Powering Modulation and Lock-In Infrared Imaging

The functionality and consumption of a Radio Frequency IDentification Integrated Circuit (RFID IC) supplied by inductive power transfer has been noninvasively analyzed. This has been done by means of an InfraRed Lock-In Thermography (IR-LIT) system and frequency modulating the RFID IC powering scheme by biasing the external powering coil considering several amplitude modulation waveforms. This generates thermal harmonics at the beating frequency in all IC blocks, enabling their detection as heat sources by IR-LIT. The main aspects addressed in this investigation have been the following: the suitability study of the proposed modulation strategies, the characterization of the coupling between coils and its effects on the RFID blocks, the RFID IC functional analysis, and the dependence of the local energy consumption on the total power delivered to the die. In addition, it has been determined that the RFID IC presents a dysfunction due to the deactivation of some blocks during operation. Results suggest that this unexpected behavior is due to a desynchronization between some of the RFID blocks. Consequently, this stops the internal control signal, deactivates some specific RFID blocks, and ceases the back-telemetry block operation.