Self-testing of an analog part based on fully differential op-amps in electronic embedded systems controlled by microcontrollers

Przedstawiono nową metodę samotestowania toru analogowego opartego na wzmacniaczu w pełni różnicowym w elektronicznych systemach wbudowanych sterowanych mikrokontrolerami. Bazuje ona na nowej metodzie diagnostycznej opartej na przekształceniu transformującym próbki odpowiedzi czasowej badanej części analogowej na pobudzenie "ujemnym" impulsem prostokątnym na wejściu Vocm na krzywe identyfikacyjne w przestrzeni pomiarowej. Metoda ta pozwala na detekcję i lokalizację pojedynczych uszkodzeń parametrycznych w układach analogowych.A new self-testing method of analog parts based on fully differential op-amps in electronic embedded systems controlled by microcontrollers is presented. It bases on a new fault diagnosis method based on transformation of voltage samples of the time response of a tested part on a "negative" square pulse at the Vocm input into localization curves placed in the measurement space. The stimulation pulse is generated by the short circuit of the signal at the Vocm input to the ground. The method can be used for fault detection and single soft fault localization. For the method there were developed: the measurement procedure whose algorithm is partly implemented in the program code of the microcontroller and partly included in the configuration of its peripheral devices, the ways of selection of diagnosis method parameters such as: the duration time T of the stimulation, that is short circuit of the signal Vocm to the ground signal, the size K of the measurement space and voltage sample moments, and also the fault dictionary determined experimentally. The approach is illustrated on the microsystem controlled by the ATXmega32A4 microcontroller. A low-pass 2nd order filter in the MFB topologies was selected as the tested analog part