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 －

An RF-DC power conversion system is designed to efficiently convert far-field RF energy to DC voltages at very low received power and voltages. Passive rectifier circuits are designed in a 0.25 mum CMOS technology using floating gate transistors as rectifying diodes. The 36-stage rectifier can rectify input voltages as low as 50 mV with a voltage gain of 6.4 and operates with received power as low as 5.5 muW(22.6 dBm). Optimized for far field, the circuit operates at a distance of 44 m from a 4 W EIRP source. The high voltage range achieved at low load current make it ideal for use in passively powered sensor networks.

Efficient Far-Field Radio Frequency Energy Harvesting for Passively Powered Sensor Networks

The idea of wireless power transfer (WPT) has been around since the inception of electricity. In the late 19th century, Nikola Tesla described the freedom to transfer energy between two points without the need for a physical connection to a power source as an ?all-surpassing importance to man? [1]. A truly wireless device, capable of being remotely powered, not only allows the obvious freedom of movement but also enables devices to be more compact by removing the necessity of a large battery. Applications could leverage this reduction in size and weight to increase the feasibility of concepts such as paper-thin, flexible displays [2], contact-lens-based augmented reality [3], and smart dust [4], among traditional point-to-point power transfer applications. While several methods of wireless power have been introduced since Tesla?s work, including near-field magnetic resonance and inductive coupling, laser-based optical power transmission, and far-field RF/microwave energy transmission, only RF/microwave and laser-based systems are truly long-range methods. While optical power transmission certainly has merit, its mechanisms are outside of the scope of this article and will not be discussed.

Harvesting Wireless Power: Survey of Energy-Harvester Conversion Efficiency in Far-Field, Wireless Power Transfer Systems

More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC–DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

/pdf/micropower-energy-harvesting-1l9ase94z1.pdf

Micropower energy harvesting

More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC-DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

According to an embodiment, there is provided a power receiver including: a first rectifying circuit, a second rectifying circuit, a connecting part and a controller. The first rectifying circuit rectifies a first AC power generated by a first AC power generating device. The second rectifying circuit rectifies a second AC power generated by a second AC power generating device. The connecting part electrically connects an output terminal of the first rectifying circuit and an output terminal of the second rectifying circuit, in parallel. The controller performs a control such that the first AC power generating device and the second AC power generating device do not operate simultaneously.

Power receiver and charging system

A 0.13um CMOS pre-power amplifier with 90dB gain range is fabricated. The pre-power amplifier consists of 4 variable attenuators and 3 fixed gain amplifiers, where the proposed attenuator suppresses the attenuation variation due to Vth variation. The pre-power amplifier outputs +4dBm with 75mW and -80dBm with 65mW. The ACPR is -48dBc and the EVM is less than 1.0% at Pout = +4dBm. The attenuation variation of less than +/-5dB is achieved.

A 0.13 μm CMOS 90 dB variable gain pre-power amplifier using robust linear-in-dB attenuator

A 1.9 GHz quadrature modulator with on-chip 90/spl deg/ phase-shifter was fabricated in a silicon bipolar technology. An image-rejection ratio over 45 dB and a carrier feed-through below -40 dBc were attained at -15 dBm local input power from 2.7 V supply. A die size of quadrature modulator IC is 2.49 mm/spl times/2.14 mm.

http://ieeexplore.ieee.org/iel2/4599/12952/00587887.pdf

A low local input power 1.9 GHz Si-bipolar quadrature modulator without any adjustment

A 2 GHz up-converter uses 0.25 /spl mu/m CMOS. Current adding and self-switching mixers are used for 1 V operation. A -40 dBc LO leakage within a 20 mV offset is achieved using a DC offset canceller. The measurement results at 1 V supply are 6.7 dB conversion gain, 6.5 dBm OIP3, /spl plusmn/2 dB gain deviation from -33 to 75/spl deg/, and 49 mW consumption.

A 1-V 2-GHz CMOS Up-Converter using Self-Switching Mixers

A direct conversion transmitter IC including a proposed frequency doubler, a quadrature modulator, and a 3-bit variable attenuator was fabricated using BiCMOS technology with f_T of 12 GHz. This architecture employing frequency doubler is intended for realizing wireless terminals that are low in cost and small in size. The architecture is effective for reducing serious interference between PA and VCO by making the VCO frequency different from that of PA. The proposed frequency doubler comprises a current-driven 90° phase-shifter and an ECL-EXOR circuit for both low power operation and wide input power range of local oscillator (LO). The proposed frequency doubler keeps high output power even when rectangular wave from LO is applied owing to use of the current-driven 90° phase-shifter instead of a voltage-driven 90° phase-shifter. An LO leakage of less than −25 dBc, an image rejection ratio in excess of 45 dBc, and a maximum attenuation of 21 dB were measured. The transmitter IC successfully operates at LO power above −15 dBm and consumes 68 mA from 2.7 V power supply voltage. An active die size is 1.5 mm×3 mm.

Shoji Otaka

Papers

Power receiver and charging system

A 0.13 μm CMOS 90 dB variable gain pre-power amplifier using robust linear-in-dB attenuator

A low local input power 1.9 GHz Si-bipolar quadrature modulator without any adjustment

A 1-V 2-GHz CMOS Up-Converter using Self-Switching Mixers

A 1.9-GHz Direct Conversion Transmitter IC with Low Power On-Chip Frequency Doubler