Using a square-wave signal for fault diagnosis of analog parts of mixed-signal electronic embedded systems

This paper presents a new approach to the detection and localization of single hard and soft faults of analog parts in embedded mixed-signal electronic systems controlled with microcontrollers, DSPs, or Systems-on-a- Chip (SoCs) (generally control units). The approach consists of three stages: a pretesting stage of creation of the fault dictionary using identification curves, a measurement stage based on stimulating the tested circuit by a square-wave signal generated by the control unit, and measurements of voltage samples of the circuit response by the internal ADC of the control unit. In the final stage, fault detection and localization are performed by the control unit. The measurement microsystem [the built-in self test (BIST)] consists only of internal devices of the control unit already existing in the system. Hence, this approach simplifies the structure of BISTs, which allows reduction of test costs. The results of experimental verification of the approach are included in this paper.