A Closed-Loop &lt;formula formulatype="inline"&gt; &lt;tex Notation="TeX"&gt;$\Sigma\Delta$&lt;/tex&gt;&lt;/formula&gt; Interface for a High-Q Micromechanical Capacitive Accelerometer With 200 ng/&lt;formula formulatype="inline"&gt;&lt;tex Notation="TeX"&gt;$ \surd$&lt;/tex&gt;&lt;/formula&gt;Hz Input Noise Density

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In this paper, an interface circuit for a three-axis digital tunneling resistance-type magnetic sensor in a standard 0.5 µm CMOS technology is presented. The weak signal detection is achieved by the chopper instrumentation amplifier. The conversion between analog and digital is achieved by the fully differential fourth-order forward Sigma-Delta modulator. The output zero-bias of magnetic sensor is corrected by digital auto-offset circuit. The design and fabrication of tunneling resistance-type magnetic sensor interface ASIC with digital output have been achieved by the research. The performance of magnetic sensor is shown as below: the sensor is at 5 V operating voltage, the value of consumption is only 120 mW; the nonlinear of the sensor is 0.1%FS; the zero reference output is less than 10 nT; the equivalent input noise density is less than 0.13 nT/Hz 1/2 (at 10 Hz).

Section: Sensor Elementmentioning

confidence: 99%

Study of a three-axis digital tunneling resistance-type magnetic sensor

Yin

Chen

et al. 2016

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“…To save chip area, virtual switch technique is not employed in all of switches. Only used in the first order integrator that will highly affect the performance of the whole system and transmission path of signal that will change with the charge feedthrough [5,6,7].…”

Section: Proposed Architecturementioning

confidence: 99%

A high performance with low harmonic distortion interface circuit of sigma-delta accelerometer

Chen

Liu

et al. 2016

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A high performance interface circuit of sigma-delta accelerometer with low harmonic distortion used many kinds of circuit processing techniques is presented in this work. Multi-bit, dynamic element matching, correlated-double-sampling and electrostatic force feedback linearization circuit are used simultaneously in order to achieve the design indicators. Because of the usage of multi-bit, the design to operational amplifier (OPA) becomes easier, and only a single-stage folded-cascode amplifier is used in the modulator, the OSR is only 64. It highly reduced the difficulty of circuit. The test results indicate that the chip area is only about 10 mm 2 and the power dissipation is 10 mW with a sampling frequency of 60 kHz. The dynamic range (DR) of the system can be lower than −130 dB, the SNR and SNDR reach to −120 dB and −110 dB respectively with a resolution about 17 bits when referred to 3g full scale DC acceleration under CMOS 0.5 µm process. The dc nonlinearity of it is 0.2%. This paper realizes an approach which can both simplify the design of the interface circuit and improve the performance of it.

“…Sigmadelta (AEÁ) interface is attractive for MEMS accelerometer since it is simple, provides a digital output, and has a large bandwidth [2]. Many capacitive accelerometer interfaces using direct AEÁ modulator structure have been published [3,4,5], however as the large mechanical and parasitic capacitors must be charged and discharged on the rhythm of the high oversampling clock of the modulator, leading to high power consumption.…”

Section: Introductionmentioning

confidence: 99%

A low power consumption inverter-based ΣΔ interface for capacitive accelerometer

Liu¹,

Xiao²,

2018

A low power dissipation sigma-delta (ΣΔ) interface for closedloop capacitive accelerometer is presented. In order to reduce the power consumption, the front-end circuit blocks work on a much lower frequency than the electronic ΣΔ modulator, and a cascode inverter with dynamic bias is used as an operational amplifier in electronic ΣΔ modulator, reducing the power dissipation greatly and enhancing the immunity to PVT variations. The measured results indicate that, the total power dissipation is 2.2 mW from a 3.3 V power supply. The noise floor of the accelerometer is 7.2 µg/Hz 1/2 in a closed-loop operation, and the achieved figure of merit (FOM, 8 pW/Hz) is better than the previously reported works.