Real-Time Supply Voltage Sensor for Detecting/Debugging Electrical Timing Failures

Debugging electrical timing bugs consumes a significant portion of validation efforts. The main cause of this problem is that electrical bugs appear as one-cycle bit-flips under only a certain operating condition such as voltage, temperature and frequency. In addition, run-time detection of a suspicious electrical bug is drawing attention for enabling voltage over-scaling and/or ensuring reliable operations. In this work, we focus on power supply noise as a primary cause of electrical bugs and propose a supply voltage sensor which achieves one-shot and every-cycle sensing. The proposed sensor can provide cycle-accurate voltage variation for detecting and debugging electrical bugs. The performance of the sensor is evaluated on an FPGA, and the measured voltage resolution is 29mV. An observed correlation between sensing results and a processor failure suggests the utility of the proposed sensor for debugging.