Diagnosis of fully differential circuits based on a fault dictionary implemented in the microcontroller systems

A new Built-In-Self-Test scheme for diagnosis of analog fully differential linear circuits embedded in a mixed-signal microsystem is presented. Only single testing frequency is used. During testing the magnitude and phase of the output differential voltage are measured. The fault detection and single fault localization procedure is based on the fault dictionary stored in the program memory of the microcontroller. The great advantage of the magnitude–phase measurement space is the shape of fault signature trajectories. In the polar coordinates trajectories have the shape of the segments of a circle or a line with simple analytical description. This implies that the dictionary has a very concise form. BIST can be realized by the internal resources of the microcontroller already existing in the tested system.