Shuou Nomura

A 63-mW H.264/MPEG-4 audio/visual codec LSI with module-wise dynamic Voltage/frequency scaling

A single-chip H.264 and MPEG-4 audio-visual LSI for mobile applications including terrestrial digital broadcasting system (ISDB-T / DVB-H) with a module-wise, dynamic voltage/frequency scaling architecture is presented for the first time. This LSI can keep operating even during the voltage/frequency transition, so there is no performance overhead. It is realized through a dynamic deskewing system and an on-chip voltage regulator with slew rate control. By the combination with traditional low power techniques such as embedded DRAM and clock gating, it consumes only 63 mW in decoding QVGA H.264 video at 15 frames/sec and MPEG-4 AAC LC audio simultaneously.

A 9.7mW AAC-Decoding, 620mW H.264 720p 60fps Decoding, 8-Core Media Processor with Embedded Forward-Body-Biasing and Power-Gating Circuit in 65nm CMOS Technology

A AAC-decoding, H.264 decoding, media processor with embedded forward-body-biasing and power-gating circuit in CMOS technology is proposed. Since all the components necessary for the scheme are simple MOS circuits requiring no extra supply voltages, they can be placed and routed by a commercial CAD tool. A data-mapping flip-flop was proposed as a high performance and low-power flip-flop. It is concluded that the power dissipation in H.264 720p 60fps decoding of 620mW at the process fast corner is the lowest among the processor-based solutions.

A process variation compensation scheme using cell-based forward body-biasing circuits usable for 1.2V design

A cell-based forward body-biasing technique to suppress the global process variation and its design flow are proposed. Latch-up free operation is guaranteed by embedded current source cells and limiter cells even when supply voltage is 1.2 V with small area overhead. By applying this technique to a media processor, the worst-case delay is reduced by 20% without sacrificing the maximum leakage spec.

A low-power multi-core media co-processor for mobile application processors

A multi-core co-processor for mobile application processors is introduced. It provides low-power, high-throughput, fully software-based acceleration of multimedia processing. The test chip fabricated in a 65nm CMOS technology consumes 620mW in H.264 720p 60fps decoding and 9.7mW in MPEG-4 AAC decoding. In the maximum workload of H.264 decoding, a symmetrical parallelization achieves 7.5× performance enhancement by 8 cores. The shared L2 cache reduces the required rate of main memory access to 310MB/s. In the minimum workload of AAC decoding, three low-power circuit techniques reduce 98% of leakage. On-chip regulators, which also work as power-gating switches, lower the supply voltage of processing cores. Embedded forward body-biasing circuit reduces Vt variations. A low-power and fast data-mapping F/F relaxes the timing constraint, which enables a reduction in the number of low-Vt transistors.

A fully integrated analog front end LSI for 9600/4800 bps modems

An analog front end LSI for 9600/4800-b/s modems has been developed. To reduce total error rate, group delay time equalizers (GDT-EQLs) for bandlimiting filters are integrated on the chip. Noise level is suppressed to -77 dBm without the GDT-EQL. Relative GDT characteristics of Tx and Rx filters are less than 80 mu s in the frequency range from 800 Hz to 3.0 kHz.<<ETX>>