Off-line BIST in Watt Hour Meters

In this work the concept, circuits and algorithms for an efficient off-line Built-In Self-Test (BIST) in watt hour meters are presented. On-chip signal generator is needed and additional digital hardware is necessary to evaluate the result. For a good signal to noise ratio (SNR) as well as good frequency resolution, a large number of samples would be needed to accurately calculate the FFT of the result. This approach is time-consuming and inappropriate for BIST, since it requires too much silicon area. We tried to avoid FFT calculation and replace it with small digital hardware and hardware algorithm running on the chip. The most important errors, which may happen in measurement path during the operation of the watt hour meter, can be efficiently detected. The parameters obtained by the suggested BIST hardware/algorithm were compared to the results obtained by the FFT for verification. The results confirm that the proposed concept of BIST could be used for an efficient on chip and off-line built-in self-test.