Autonomous di/dt noise control scheme for margin aware operation

This paper demonstrates the first trial of an autonomous and margin aware di/dt noise control scheme. A di/dt on the power line is detected by a mutual inductor, the induced voltage is multiplied by Gilbert multiplier and the following low pass filter outputs a DC voltage in proportion to the di/dt noise. The DC voltage is compared with reference voltages, and the modes of the internal circuit is controlled depending on the comparators output. By using this scheme, the di/dt noise power can be autonomously controlled to fall within a defined range set by the reference voltages. We use two operation modes here: all-active and half-active modes. Our experimental results show that the internal circuit oscillates between the all-active and the half-active modes, also show that the all/half ratio and the oscillation frequency changes depending on the reference voltages. It proves that our autonomous di/dt noise control scheme works as being designed.