A Power-Efficient Readout for Wheatstone-Bridge Sensors With COTS Components

Jiang, Hui; Vogel, Johan G.; Nihtianov, Stoyan

doi:10.1109/jsen.2017.2755074

Cited by 8 publications

(1 citation statement)

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“…As shown in Fig. 16(b), the water-level difference in a U-tube manometer was precisely controlled by a linear stage to create a well-defined differential pressure [30].…”

Section: B System Measurements and Temperature Calibrationmentioning

confidence: 99%

An Energy-Efficient 3.7-nV/<inline-formula> <tex-math notation="LaTeX">$\surd$ </tex-math> </inline-formula>Hz Bridge Readout IC With a Stable Bridge Offset Compensation Scheme

Jiang

Nihtianov

Makinwa

2019

IEEE J. Solid-State Circuits

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This paper describes an energy-efficient bridge readout IC (ROIC), which consists of a capacitively coupled instrumentation amplifier (CCIA) that drives a continuous-time delta-sigma modulator (CTM). By exploiting the CCIA's ability to block dc common-mode voltages, the bridge's bias voltage may exceed the ROIC's supply voltage, allowing these voltages to be independently optimized. Since bridge output is typically much smaller than bridge offset, a digital to analog converter (DAC) is used to compensate this offset before amplification and thus increase the CCIA's useful dynamic range. Bridge loading is reduced by using a dual-path positive feedback scheme to boost the CCIA's input impedance. Furthermore, the CCIA's output is gated to avoid digitizing its output spikes, which would otherwise limit the ROIC's linearity and stability. The ROIC achieves an input-referred noise density of 3.7 nV/ √ Hz, a noise efficiency factor (NEF) of 5, and a power efficiency factor (PEF) of 44, which both represent the state of the art. A pressure sensing system, built with the ROIC and a differential pressure sensor (AC4010), achieves 10.1-mPa (1σ) resolution in a 0.5-ms conversion time. The ROIC dissipates about 30% of the system's power dissipation and contributes about 6% of its noise power. To reduce the sensor's offset drift, a temperature compensation scheme based on an external reference resistor is used. After a two-point calibration, this scheme reduces bridge offset drift by 80× over a 50°C range. Index Terms-Beyond the rails, bridge offset compensation, bridge sensor, capacitively coupled (CC) chopper, CC instrumentation amplifier (CCIA), continuous-time delta-sigma modulator (CTM), energy efficient, readout IC (ROIC), temperature compensation. This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination.

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“…As shown in Fig. 16(b), the water-level difference in a U-tube manometer was precisely controlled by a linear stage to create a well-defined differential pressure [30].…”

Section: B System Measurements and Temperature Calibrationmentioning

confidence: 99%