Katsuhiro Seta

50% active-power saving without speed degradation using standby power reduction (SPR) circuit

High-speed and low-power are required for multimedia LSIs, since portability with battery operation is sometimes the key factor for multimedia equipment, while delivering giga operations per second (GOPS) processing power for digital video use. To understand circuit delay and power dissipation dependence on power supply voltage (V/sub DD/) and threshold voltage of MOSFETs (V/sub TH/), a typical logic circuit is investigated. Fanout is chosen to be 5 which corresponds to the statistical average of gate load in ASICs. A simulated delay dependence on V/sub DD/ and V/sub TH/ is presented. The same V/sub TH/ is chosen for nMOS and pMOS. It is shown that if V/sub TH/ is reduced to 0.3V, V/sub DD/ can be decreased down to 2V while maintaining the speed at V/sub TH/=0.7V and V/sub DD/=3V which is the typical operation condition for high-speed LSIs. The active power dissipation, in this case, is reduced by more than 50%.

200 MHz video compression macrocells using low-swing differential logic

Improving the performance of fully dedicated macrocells is key to realizing HDTV-resolution video de/compression LSIs operating at more than 100 MHz, having reasonable power consumption and chip size small enough for consumer applications. Existing circuit techniques are either not sufficiently fast or are area consuming. However, these problems are overcome by using low-swing differential logic to realise such macrocells.<<ETX>>

A single-chip MPEG2 video decoder LSI

This MPEG2 video decoder LSI decodes MPEG2 standard bit streams. The compression algorithm in the MPEG2 is based on discrete cosine transform (DCT), variable length coding, and motion compensation similar to the MPEG1, the earlier standard. However, the processing speed should be more than four times faster than MPEG1. Moreover, several algorithms and structures to handle interlaced pictures are added to the MPEG1 standard. This LSI decodes in real time all motion-compensation modes and picture structures in MPEG2 bit streams of not only CCIR601 but also HDTV resolution.<<ETX>>

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.

0.5- mu m 3.3-V BiCMOS standard cells with 32-kilobyte cache and ten-port register file

BiCMOS standard cell macros, including a 0.5-W 3-ns register file, a 0.6-W 5-ns 32-kbyte cache, a 0.2-W 3-ns table look-aside buffer (TLB), and a 0.1-W 3-ns adder, are designed with a 0.5- mu m BiCMOS technology. A supply voltage of 3.3 V is used to achieve low power consumption. Several BiCMOS/CMOS circuits, such as a self-aligned threshold inverter (SATI) sense amplifier and an ECL HIT logic are used to realize high-speed operation at the low supply voltage. The performance of the BiCMOS macros is verified using a fabricated test chip. >

0.5/spl mu/m 2M-transistor BipnMOS Channelless Gate Array

A channelless gate array has been realized using 0.5- mu m BiCMOS technology integrating more than two million transistors on a 14-mm*14.4-mm chip. A small-size PMOS transistor and a small-size inverter are added to the conventional BiNMOS gate to form the BiPNMOS gate. The gate is suitable for 3.3-V supply and achieves 230-ps gate delay for a two-input NAND with full-swing output. Added small-size MOS transistors in the BiPNMOS basic cell can also be used for memory macros effectively. A test chip with four memory macros-a high-speed RAM, a high-density RAM, a ROM, and a CAM macro-was fabricated. The high-speed memory macros utilize bipolar transistors in bipolar middle buffers and in sense amplifiers. The high-speed RAM macro achieves an access time of 2.7 ns at 16-kb capacity. The high-density RAM macro is rather slow but the memory cell occupies only a half of the BiPNMOS basic cell using a single-port memory cell. >

Area-Efficient Selective Multi-Threshold CMOS Design Methodology for Standby Leakage Power Reduction

This paper presents a design flow for an improved selective multi-threshold (selective-MT) circuit. The selective-MT circuit is improved so that plural MT-cells can share one switch transistor. We propose the design methodology from RTL (register transfer level) to final layout with optimizing switch transistor structure.

Special memory and embedded memory macros in MPEG environment

Special memory and embedded memories used in a newly designed MPEG2 decoder LSI are described. Orthogonal memory is employed in a IDCT (Inverse Discrete Cosine Transform) block for small area and power. FIFOs and other dual-port memories are designed by using a single-port RAM operated twice in one clock cycle to reduce cost. As for testability, direct test mode is implemented for small area. An instruction RAM is placed outside the pad area in parallel to a normal instruction ROM and activated by Al-masterslice for extensive debugging and an early sampling. Other memory related techniques and the key features of the decoder are also described.

0.5 mu m BiCMOS standard-cell macros including 0.5 W 3 ns register file and 0.6 W 5 ns 32 kB cache

BiCMOs standard-cell macros, including a 0.5-W, 3.0-ns register file, a 0.6-W, 5.0-ns 32-kB cache, a 0.2-W, 2.5-ns table look-aside buffer (TLB), and a 0.1-W, 3.0-ns adder, are presented based on a 0.5- mu m BiCMOs technology. These power consumption values are at 100 MHz operation. Low power and high speed are crucial for high-performance systems requiring a high level of integration. Several BiCMOS/CMOS circuits achieve high-speed operation with a 3.3-V supply. A direct-coupled ECL (emitter-coupled logic)+CMOS circuit is investigated for use as a BiCMOS standard cell.<<ETX>>