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This article presents a BJT-based CMOS temperature sensor with a wide sensing range from −50 °C to 180 °C. To effectively relax the sensor resolution requirement and conversion time over the entire temperature range to improve energy efficiency, we introduce a nonlinear subranging readout scheme together with double sampling to achieve dynamic reconfiguration of the sensor readout according to the ambient temperature. We further reduce the sensor power at high temperature by devoting the $\beta $ -cancellation circuit only for BJT biasing while applying a temperature-independent bias current for the other sensor building blocks. Implemented in 0.18- $\mu \text{m}$ CMOS with four-wire connections and switch-leakage compensation based on small BJTs, the proposed sensor chip prototype achieves a high resolution-FoM of 7.2 pJ $\cdot \text{K}^{{2}}$ at 150 °C, while featuring a small sensing error of ±0.45 °C under a 1.5-V supply. [ABSTRACT FROM AUTHOR]

This paper presents an ultra-high-frequency (UHF) passive sense tag for electrical grid and substation thermal monitoring, with emphasis on the tag system optimization and the design of a low power embedded temperature sensor. The designed tag achieves a sensitivity of $-$ 12.3 dBm under active temperature monitoring operation, which is the state of the art among existing UHF passive temperature sense tag products. The sensing inaccuracy of the tag is $\pm$ 2.5 $^{\circ }$ C (3 $\sigma$) from $-$ 25 to 120 $^{\circ }$ C after a low-cost wireless single-point trim. An antimetal ceramic-packaged tag was tested by attaching to a ring main unit in the substation and complete tag system demonstrated robust wireless operation with a sensing distance of 3.5 m. The combination of batteryless and wireless operation, high sensitivity, wide sensing range, and small incident-power-dependent error ($\pm$ 0.2 $^{\circ }$ C) makes this tag suitable for the target applications. [ABSTRACT FROM AUTHOR]

This brief presents a 0.9- $\mu \text{W}$ duty-cycle-modulated temperature sensor with a sub- $\mu \text{A}$ peak current for energy harvester- or micro-battery-powered systems. A compact sensing frontend is proposed to achieve low power, together with various device-level leakage and nonlinearity compensation techniques adopted to minimize the sensor error. In addition, a current-starved multivibrator which provides inherent clamping voltages is used for duty cycle modulation for overall energy savings. The sensor designed in 0.18- $\mu \text{m}$ CMOS process achieves a resolution figure of merit of 10.6 pJ $\cdot \text{K}^{2}$ , which is among the most energy-efficient designs to date. Trimmed at 30 °C, the sensor achieves ±0.85 °C precision from −30 °C to 120 °C. The maximum supply sensitivity is 0.7 °C/V for a 1.6–2 V supply. [ABSTRACT FROM AUTHOR]

This paper presents a nano-watt class energy-efficient capacitive sensor interface with on-chip temperature compensation. To achieve both high resolution and sensing accuracies, we exploit the fundamental limits of a two-step incremental-ADC and present a systematic study on the optimal coarse/fine bit allocations in the presence of mismatch errors. Efficient hardware reuse is ensured by utilizing the same loop filter, capacitive DAC, and digital controller in coarse/fine conversions for both capacitance and temperature readouts. A reconfigurable pre-gain stage for both capacitance and temperature sensing and a block-based data weighted averaging scheme are also employed to improve the overall system efficiency with 60% control overhead reduction. Optimized biasing circuit and subthreshold-biased amplifier with indirect compensation are utilized to achieve high accuracy with nano-watt power. Fabricated in a standard 0.18- \mu \textm CMOS process, the chip prototype consumes only 570 nW and achieves measured capacitance and temperature sensing inaccuracies of ±0.17 fF ( $1\sigma$ ) from 0 to 10.8 pF and ±0.18 °C ( $3\sigma$ ) from 0 to 100 °C, respectively. System level verification with a commercial MEMS pressure sensor shows a measured pressure sensing error improvement of > $150\times$ after temperature compensation. [ABSTRACT FROM PUBLISHER]

A bipolar junction transistor (BJT)‐based CMOS temperature sensor exploiting the piecewise BJT process spread compensation property of the base recombination current is proposed to reduce the process variations of the base–emitter voltage (Vbe). The weighted combinations of different on‐chip resistors are explored to minimise their associated process spread. Fabricated in standard 0.18‐μm CMOS, the chip prototype occupies an active area of 0.036 mm2 and draws 3 μA from a 1.2 V supply, with a measured maximum inter‐/intra‐die variation in Vbe of <1.5 mV from −40 to 125°C from two batches. Using the measured Vbe, ΔVbe and the first‐batch‐only calibration parameters, the chip prototype demonstrates an untrimmed batch‐to‐batch inaccuracy of ± 1.5°C (3σ) within the same temperature range (24 samples from 2 batches). [ABSTRACT FROM AUTHOR]

This paper presents a system-on-chip passive RFID tag with an embedded temperature sensor for the EPC Gen-2 protocol in the 900-MHz UHF frequency band. A dual-path clock generator is proposed to support both applications with either very accurate link frequency or very low power consumption. On-chip temperature sensing is accomplished with a time-readout scheme to reduce the power consumption. Moreover, a gain-compensation technique is proposed to reduce the temperature sensing error due to process variations by using the same bandgap reference of the tag to generate bias currents for both the current-to-digital converter and the clock generator of the sensor. Also integrated is a 128-bit one-time-programmable (OTP) memory array based on gate-oxide antifuse without extra mask steps. Fabricated in a standard 0.18-\mum CMOS process with analog options, the 1.1-mm^2 tag chip is bonded onto an antenna using flip-chip technology to realize a complete tag inlay, which is successfully demonstrated and evaluated in real-time wireless communications with commercial RFID readers. The tag inlay achieves a sensitivity of -\6 dBm and a sensing inaccuracy of \pm\0.8^\circC (3 \sigma inaccuracy) over operating temperature range from -\20^\circC to 30^\circC with one-point calibration. [ABSTRACT FROM PUBLISHER]