A High-Resolution Accelerometer With Electrostatic Damping and Improved Supply Sensitivity

作者：Yucetas Mikail^*; Pulkkinen Mika; Kalanti Antti; Salomaa Jarno; Aaltonen Lasse; Halonen Kari

来源：IEEE Journal of Solid-State Circuits, 2012, 47(7): 1721-1730.

DOI：10.1109/JSSC.2012.2191675

• Accelerometers
• microelectromechanical systems
• high Q
• damping
• force feedback
• open-loop systems
• self-balancing bridge
• ratiometric output
• delta-sigma analog-digital conversion

In this paper, a charge-balancing accelerometer is presented. A hybrid interface topology is utilised to achieve high resolution, high linearity and low power supply sensitivity. The accelerometer consists of a micromechanical sensor element, a self-balancing bridge (SBB) open-loop readout, AC force feedback and ADC. The SBB converts acceleration to ratiometric voltage. The ratiometric output of the SBB is converted to the digital domain by the ADC. In order to achieve high resolution, a micromechanical sensor element with a high quality factor, Q, is utilised. The Delta Sigma AC force feedback is used for damping the high Q to get a low settling time. The sensor interface is fabricated in a standard 0.35 mu m CMOS process. The fabricated chip has an area of 6.66 mm(2) and consumes 1 mA at a nominal supply voltage of 3.6 V. The sensor has a maximum DC nonlinearity of 1.3% over the commercial temperature range with an input range of +/- 1.15 g. The noise floor of the sensor is around 2 mu g/root Hz and the signal bandwidth is 200 Hz. The bias instability is 13 g and the sensor gain variation is less than 5% in the 3-3.6 V supply range.

• 出版日期2012-7