Defense Event

Scalable Energy-Recovery Architectures

Tai-Chuan Ou

Wednesday, September 09, 2015
3:00pm - 5:00pm
3725 BBB

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About the Event

Energy efficiency is a critical challenge for today’s integrated circuits, especially for high-end digital signal processing and communications that require both high throughput and low energy dissipation for extended battery life. Charge-recovery logic recovers and reuses charge using inductive elements and has the potential to achieve order-of-magnitude improvement in energy efficiency while maintaining high performance. However, the lack of large-scale high-speed silicon demonstrations and inductor area overheads are two major concerns. This dissertation focuses on scalable charge-recovery designs. We present a semi-automated design flow to enable the design of large-scale charge-recovery chips. We also present a new architecture that uses in-package inductors, eliminating the area overheads caused by the use of integrated inductors in high-performance charge-recovery chips. To demonstrate our semi-automated flow, which uses custom-designed standard- cell-like dynamic cells, we have designed a 576-bit charge-recovery low-density parity- check (LDPC) decoder chip. Functioning correctly at clock speeds above 1GHz, this prototype is the first-ever demonstration of a GHz-speed charge-recovery chip of significant complexity. In terms of energy consumption, this chip improves over recent state-of-the-art LDPCs by at least 1.3× with comparable or better area efficiency. To demonstrate our architecture for eliminating inductor overheads, we have designed a charge-recovery LDPC decoder chip with in-package inductors. This test- chip has been fabricated in a 65nm CMOS flip-chip process. A custom 6-layer FC-BGA package substrate has been designed with 16 inductors embedded in the fifth layer of the package substrate, yielding higher Q and significantly improving area efficiency and energy efficiency compared to their on-chip counterparts. From measurements, this chip achieves at least 2.3× lower energy consumption with even better area efficiency over state-of-the-art published designs.

Additional Information

Sponsor(s): ECE

Faculty Sponsor: Marios Papaefthymiou

Open to: Public