This page highlights ongoing research into Energy-Recovering VLSI at the University of Michigan Advanced Computer Architecture Laboratory.

Objectives

• Demonstrate the practicality of single-phase energy recovery for low-energy high-speed VLSI design.
• Design testable prototype of nontrivial size and complexity.
• Achieve working first silicon using a conservative design approach.
• Validate simulation results with experimental energy measurements.
• Demonstrate combined operation of integrated power-clock with clock distribution and PMOS energy recovering flip-flop (PTERF).

Results

• Designed and fabricated resonant-clocked energy-recovering ASIC in a 0.25 bulk silicon process.
• Correct operation validated above 300MHz with self-test logic and integrated power-clock generator.
• Measured power dissipation in energy recovering mode up to 2X lower than in conventional (non-energy recovering) mode.
• Objectives were successfully met, demonstrating the potential of energy recovering design for low-energy VLSI.

Talks

• Energy Recovering ASIC Design, ISVLSI 2003 ( PPT )


• Energy Recovering Computers, IBM Austin Conference on Energy Efficient Design, February 2003 ( PPT )


• Energy Recovery Design for Low-Power ASICs, SOC 2003 ( PPT )

Papers

• Energy Recovering ASIC Design, ISVLSI 2003 ( PDF)
• Energy Recovery Design for Low-Power ASICs, SOC 2003 ( PDF)

Past Research

True Single-Phase Adiabatic Multiplier

Energy Recovery Principle

During the operation of conventional CMOS circuitry, charge is transferred between circuit capacitors and fixed power supply voltages. The per-cycle energy consumption of CMOS designs is thus proportional to the product CV^2, where C is the total switched capacitance, and V is the difference between the power and ground voltages. In energy recovery design, charge is transferred in a controlled manner across low voltage drops. Furthermore, the energy stored in certain large capacitive nodes in a VLSI design is recovered through the use of inductors or a network of switched capacitors.

Acknowledgments

This research was supported in part by the US Army Research Office under Grants No. DAAD19-99-1-0304 and No. DAADD19-03-1-0122.