A 62μA Interface ASIC for a Capacitive 3-Axis Micro-Accelerometer

0.0354mm 82μW 125KS/s 3-axis readout circuit for capacitive MEMS accelerometer

“…Yet the CDC detects the end edge of the "WAKE" signal, it will turn off the ring oscillator to save much power consumption and enter standby mode. Furthermore, the distinctive output in acceleration and direction makes our proposal more suitable for system-level integration than the other works [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. In practical ADC based approaches, the acceleration is defined as the number of N bias ±N acc and N acc takes a half ratio in output code, where N bias & N acc stand for steady output value and acceleration value.…”

“…The differential capacitive accelerometer has some advantages such as zero static bias current, the capability of high sensitivity, differential capacitance output which against the common mode influence, excellent thermal stability, and having good ability for low-power applications [2]. Based on the above advantages, a low-power capacitive accelerometers, including capacitance-to-voltage and ADC, have been presented in [3].…”

“…The PVT variation can be minimized by using the above technologies but power dissipation and circuit area remain to be reduced, especially for multi-axis and multi-sensor solutions. Matii Paavola et al employ the algorithmic capacitance ratio-independent ADC and voltage scaling technique to minimize power dissipation under acceptable silicon area [3]. In this paper, we propose a new power/area efficient readout circuit which has the following features: (1) exploiting event driven approach to reduce power consumption, (2) hardware sharing to minimize area for multi-axis, and (3) adjustable resolutions for different applications.…”

“…Finally, the digital code will be used for digital signal processor (DSP) or other applications in system platforms. In traditional capacitive readout circuits [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], there are some kinds of methods, including capacitance to voltage [1-8, 10, 12-14, 16-19], capacitance to time [9,11] and capacitance to frequency converters [15]. Furthermore, the capacitance to voltage circuits can be classified into four categories: differential, synchronous detection, switched capacitance and sigma-delta modulator.…”

Nano‐ampere PTAT current source with temperature inaccuracy <±1°C

“…Methods such as dynamic voltage scaling [2] are quite common to address this problem in digital circuits, but they are not easily implementable with analogue blocks. Thus, to reduce temperature dependency in analogue blocks, a temperature dependence nullifier or an on‐chip temperature sensor required for efficient dynamic thermal management [3]. Proportional to absolute temperature (PTAT) current sources are quite commonly used in mixed signal circuits to reduce thermal dependence.…”