Resonant magnetic field sensor with frequency output

Sunier, R.; Li, Y.; Kirstein, K.-U.; Vancura, T.; Baltes, H.; Brand, Oliver

doi:10.1109/memsys.2005.1453936

Cited by 15 publications

(17 citation statements)

References 26 publications

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“…This strategy is used in [11] and [12] with low phase-noise and good frequency stability. However, manual phase adjustments are required, which are not acceptable for high-volume applications.…”

Section: A Phase Lockingmentioning

confidence: 99%

“…Given their good sensitivity and low power consumption, Lorentz force based MEMS magnetometers have become a hot topic with numerous publications in the last years [11]- [23]. Moreover, taking advantage of the Back-End-Of-Line (BEOL) metal layers in a CMOS technology [24], it is possible to integrate Lorentz force magnetometers together with accelerometers and gyroscopes in the same die area of the electronics [25], [26], thus, reducing fabrication cost and area.…”

Section: Introductionmentioning

confidence: 99%

“…Current advances in the literature of MEMS magnetometers can be divided into two groups. On one hand, new MEMS devices in different technologies have been proposed [11]- [14]. On the other hand, in order to generate the Lorentz force, AC current driving is needed, which upconverts the measured baseband magnetic field into a double-sideband signal around the driving current frequency.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, in order to generate the Lorentz force, AC current driving is needed, which upconverts the measured baseband magnetic field into a double-sideband signal around the driving current frequency. Then, an electrostatic drive may be applied, whose phase respect to current driving can make the output signal to be amplitude [15] or frequency modulated [11]. For this reason, new modulation techniques are an important part of the literature.…”

Section: Introductionmentioning

confidence: 99%

“…For this reason, new modulation techniques are an important part of the literature. Also, the technique used to drive the sensor, either using open-or closed-loop has received researchers interest [11], [12], [16]- [23]. This work is focused in two important aspects to take into account if MEMS magnetometers are to be introduced in the market.…”

Section: Introductionmentioning

confidence: 99%

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A Mixed-Signal Control System for Lorentz-Force Resonant MEMS Magnetometers

et al. 2019

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This paper presents a mixed-signal closed-loop control system for Lorentz force resonant MEMS magnetometers. The control system contributes to 1) the automatic phase control of the loop, that allows start-up and keeps self-sustained oscillation at the MEMS resonance frequency, and 2) output offset reduction due to electrostatic driving by selectively disabling it. The proposed solution proof-of-concept has been tested with a Lorentz force-based MEMS magnetometer. The readout electronic circuitry has been implemented on a printed circuit board with off-the-shelf components. Digital control has been implemented in an FPGA coded with VHDL. When biased with 1 V and a driving current of 300 µA rms , the device shows 9.75 pA/µT sensitivity and total sensor white noise of 550 nT/ √ Hz. Offset when electrostatic driving is disabled is 793 µT, which means a 40.1% reduction compared when electrostatic driving is enabled. Moreover, removing electrostatic driving does not worsen bias instability, which is lower than 125 nT in both driving cases.

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Section: A Phase Lockingmentioning

confidence: 99%