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[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

We present design techniques that make possible the operation of analog circuits with very low supply voltages, down to 0.5 V. We use operational transconductance amplifier (OTA) and filter design as a vehicle to introduce these techniques. Two OTAs, one with body inputs and the other with gate inputs, are designed. Biasing strategies to maintain common-mode voltages and attain maximum signal swing over process, voltage, and temperature are proposed. Prototype chips were fabricated in a 0.18-/spl mu/m CMOS process using standard 0.5-V V/sub T/ devices. The body-input OTA has a measured 52-dB DC gain, a 2.5-MHz gain-bandwidth, and consumes 110 /spl mu/W. The gate-input OTA has a measured 62-dB DC gain (with automatic gain-enhancement), a 10-MHz gain-bandwidth, and consumes 75 /spl mu/W. Design techniques for active-RC filters are also presented. Weak-inversion MOS varactors are proposed and modeled. These are used along with 0.5-V gate-input OTAs to design a fully integrated, 135-kHz fifth-order elliptic low-pass filter. The prototype chip in a 0.18-/spl mu/m CMOS process with V/sub T/ of 0.5-V also includes an on-chip phase-locked loop for tuning. The 1-mm/sup 2/ chip has a measured dynamic range of 57 dB and draws 2.2 mA from the 0.5-V supply.

0.5-V analog circuit techniques and their application in OTA and filter design

This paper presents a low power boost converter for thermoelectric energy harvesting that demonstrates an efficiency that is 15% higher than the state-of-the-art for voltage conversion ratios above 20. This is achieved by utilizing a technique allowing synchronous rectification in the discontinuous conduction mode. A low-power method for input voltage monitoring is presented. The low input voltage requirements allow operation from a thermoelectric generator powered by body heat. The converter, fabricated in a 0.13 μm CMOS process, operates from input voltages ranging from 20 mV to 250 mV while supplying a regulated 1 V output. The converter consumes 1.6 (1.1) μW of quiescent power, delivers up to 25 (175) μW of output power, and is 46 (75)% efficient for a 20 mV and 100 mV input, respectively.

A 20 mV Input Boost Converter With Efficient Digital Control for Thermoelectric Energy Harvesting

A 0.5-V third-order one-bit fully-differential continuous-time DeltaSigma modulator is presented. The presented modulator architecture uses true low-voltage design techniques, and does not require internal voltage boosting or low-threshold devices. A return-to-open architecture that enables the ultra-low-voltage realization of return-to-zero signaling for the feedback DAC is proposed. The ultra-low-voltage operation is further enabled by a body-input gate-clocked comparator, and body-input operational transconductance amplifiers for the active-RC loop filter. Fabricated on a 0.18-mum CMOS process, the modulator achieves a peak SNDR of 74 dB in a 25 kHz bandwidth, and occupies an area of 0.6 mm2; the modulator core consumes 300 muW.

A 0.5-V 74-dB SNDR 25-kHz Continuous-Time Delta-Sigma Modulator With a Return-to-Open DAC

We present a modular power management system that can harvest energy from three sources simultaneously, with available power levels of 25 nW to $100~\mu \text {W}$ , with one inductor. The DC-DC converter is clocked with energize and dump pulses, and the pulse-widths are generated for constant peak inductor current and for no reversal, without current sensing. We use a comparator to reach the open-circuit-voltage (OCV)-based maximum power point (MPP), and train an oscillator to mimic the comparator output. The oscillator frequency is tuned through a successive-approximation algorithm within 11 comparator cycles. The 180 nm chip has a maximum efficiency of 87% at an input available power of $20~\mu \text {W}$ (input voltage of 0.6 V), and has an output voltage of 1.5 V.

An 18 nA, 87% Efficient Solar, Vibration and RF Energy-Harvesting Power Management System With a Single Shared Inductor

Circuits (Fig. 1) that operate with power supplies (VDD) of less than 1 Volt are present. More particularly, circuits (Fig. 1) that operate with supply voltages (VDD) near or lower than the threshold voltage of the transistors (M1A, M1B) in those circuits are presented. Various circuits and embodiments such as operational transconductance amplifiers, biasing circuits, integrators, continuous-time sigma delta modulators, track-and-hold circuits, and others are presented. The techniques and circuits can be used in a wide range of applications and various transistors from metal-oxide-semiconductor (MOS) to bipolar junction transistors may implement the techniques presented herein.

Low voltage operational transconductance amplifier circuits

In this paper, a technique for the synthesis of lumped element multi-band matching networks is proposed using frequency transformations. The proposed technique has been generalized for n -bands using 1→ n frequency transformations. The effect of the transformations on the bandwidth of the matching network and the effect of inductor losses on the transducer loss of the matching network are analyzed. A strategy to improve the efficiency of the matching networks in the presence of lossy components has been proposed. Applications of the proposed synthesis technique in the development and design of new multi-band LNA/PA architectures are discussed in detail with the help of design examples. In one of the design examples, the circuit has been prototyped and measured results are presented.

Shouri Chatterjee

Papers

0.5-V analog circuit techniques and their application in OTA and filter design

A 0.5-V 74-dB SNDR 25-kHz Continuous-Time Delta-Sigma Modulator With a Return-to-Open DAC

An 18 nA, 87% Efficient Solar, Vibration and RF Energy-Harvesting Power Management System With a Single Shared Inductor

Low voltage operational transconductance amplifier circuits

Multi-Band Frequency Transformations, Matching Networks and Amplifiers