A CMOS Ripple Detector for Voltage Regulator Testing

This paper presents an RMS based ripple sensor for testing of fully integrated voltage regulators. A DC signal which is proportional to the input ripple amplitude is generated. Final digital pass/fail signal is obtained with a clocked comparator. The sensor can detect a peak-to-peak ripple voltage of up to 50 millivolts on the 1.2 V supply rail and has 220 MHz bandwidth. The sensor is designed using IBM 90 nm CMOS technology and its functionality is verified in Cadence Virtuoso simulation environment.