A Reconfigurable Auxiliary Circuit for Transient Enhancement in Processor Power Systems With Multiple Voltage Rails

This article proposes a practical auxiliary circuit for multiple voltage rails to improve dynamic response under significant load steps with an ultrafast slew rate. The proposed auxiliary circuit consists of a current injection/absorption circuit with nonlinear control that can effectively reduce undershoot and overshoot during transients, a sampling mechanism supporting its independent operation, and a reconfigurable energy path supporting multiple voltage rails. The proposed auxiliary circuit is illustrated and verified in a high-power supply system for processors with two voltage rails at different voltage levels, which effectively improves the dynamic response of both voltage rails and demonstrates robustness in fast alternating load steps without affecting regular operation. The maximum load step of 250 A with the current slew rate of 1250 A/μs is tested, and the overshoot and undershoot are reduced by 36% and 25%, respectively, with recovery times less than 9 μs. Compared with existing research and solutions, the proposed auxiliary circuit has cost and space savings advantages, better versatility to support a wide range of power supply types, and is easy to implement.