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A picowatt CMOS voltage reference with dual outputs is proposed and simulated in this paper based on a standard 65 nm process. To compensate for the leakage current caused by parasitic reverse-biased PN junctions, an approach employing gate leakage transistors is proposed. Maintaining a maximal temperature coefficient (TC) of 20.40 ppm/°C across an extended temperature range of −10∼155 °C is achieved. Additionally, a voltage divider consisting of diode-connected NMOS transistors is introduced to obtain a lower voltage output without shunting the original branch or utilizing operational amplifiers. Moreover, a novel trimming block is utilized to optimize TC across different process corners. Simulation results demonstrate that a minimum power consumption of only 53.83 pW is achieved and the line sensitivity is 0.077%/V with 0.45 V to 2.5 V supply. The power supply rejection ratio of −76.70 dB at 10 Hz and V D D = 1.8 V is obtained. [ABSTRACT FROM AUTHOR]

A high resolution, acceptable accuracy and low power consumption time-domain temperature sensor is proposed and simulated in this paper based on a 180 nm standard CMOS technology. A diode stacking structure is introduced to enhance the accuracy of the temperature sensing core. To improve the resolution of the sensor, a dual-input capacitor multiplexing voltage-to-time converter (VTC) is implemented. Additionally, a low-temperature drift voltage-mode relaxation oscillator (ROSC) is proposed, effectively reducing the large oscillation frequency drift caused by significant temperature impacts on delay errors. The simulated results show that the resolution is as high as 0.0071 °C over 0∼120 °C with +0.43 °C/−0.38 °C inaccuracy and 1.9 pJ · K2 resolution FoM, consuming only 1.48 μ W at a 1.2 V supply voltage. [ABSTRACT FROM AUTHOR]

This paper presents a picowatt voltage reference circuit using a voltage regulation scheme consisting of a self-regulation native N-type transistor, a double regulation topology formed by a stacked structure of two native N-type transistors, and a P-type transistor-based self-biased current source, to feed a diode-connected P-type load and a PNP transistor load. This improves the line sensitivity and the power supply rejection ratio (PSRR) without the use of an on-chip capacitor. The circuit is designed in a 180 nm CMOS process with an area of 13,700 μm2 and operates with a minimum supply voltage of 0.8 V. Post layout simulation results show that the circuit provides a constant output voltage of 160.2 mV with a temperature coefficient (TC) of 151.6 ppm/ ∘ C from 0 to 100 ∘ C, a line sensitivity of 0.00114%/V, a PSRR of - 72.6 dB at 100 Hz, and an untrimmed voltage accuracy ( σ / μ ) of 0.99%. [ABSTRACT FROM AUTHOR]

An indoor positioning system, with ultra-high frequency radio frequency identification based on phase difference (PD), is presented in this paper. Several groups of phases are obtained by setting reader's different transmitting frequency to reduce the phase ambiguity. Two positioning algorithms are proposed with rough PDs, which are pattern matching based on PD correction and machine learning based on without PD correction. The experiments of two methods, in which machine learning gets a better positioning precision of 0.43 m, are also presented and discussed. [ABSTRACT FROM AUTHOR]

A fully integrated and high-efficiency low-dropout regulator (LDO) with 100 mV dropout voltage and nA-level quiescent current for energy harvesting has been proposed and simulated in the 180 nm CMOS process in this paper. A bulk modulation without an extra amplifier is proposed, which decreases the threshold voltage, lowering the dropout voltage and supply voltage to 100 mV and 0.6 V, respectively. To ensure stability and realize low current consumption, adaptive power transistors are proposed to enable system tropology to alter between 2-stage and 3-stage. In addition, an adaptive bias with bounds is utilized in an attempt to improve the transient response. Simulation results demonstrate that the quiescent current is as low as 220 nA and the current efficiency reaches 99.958% in the full load condition, load regulation is 0.0059 mV/mA, line regulation is 0.4879 mV/V, and the optimal PSR is −51 dB. [ABSTRACT FROM AUTHOR]

In this paper, a high-accuracy indoor positioning system based on the ultra-wideband (UWB) technique is proposed. The proposed system uses a simple ranging process to obtain the distance between the mobile node and the fixed base stations. Besides, an improved time of arrival (ToA) algorithm with Kalman filtering is proposed to improve the positioning accuracy. Measurements have been performed in the real indoor 13m*7.6m environment with many obstacles and the root-mean-square error (RMSE) is less than 0.3m. The proposed system offers a wide range of application in robotics, industrial automation, post-sorting system and so on.

This paper presents a single-inductor boost converter for thermoelectric energy harvesting. A two-stages startup circuit with a three-phase operation is adopted to obtain self-startup with a single inductor. To extract the maximum energy, a coarse- and fine-tuning MPPT is proposed to adaptively and effectively track the internal source resistance. By designing a zero-current detector, the synchronization loss is reduced, which significantly improves the peak efficiency. The boost converter is implemented in a 0.18-μm standard CMOS process. Simulation results show that the converter self-starts the operation from a TEG voltage of 128 mV and achieves 88% peak efficiency, providing a maximum output power of 3.78 mW. The improved MPPT enables the converter to sustain the operation at an input voltage as low as 7.5 mV after self-startup. [ABSTRACT FROM AUTHOR]