A Digital-Analog Hybrid System-on-Chip for Capacitive Sensor Measurement and Control

Abstract

Sensors based on capacitance detection are common in the field of inertial measurement and have the potential for miniaturization and low power consumption. In order to control and process such sensors, a novel digital-analog hybrid system-on-chip (SoC) is designed and implemented. The system includes a capacitor to voltage (C/V) conversion circuit and a band-pass sigma-delta modulator (BPSDM) as the analog-to-digital converter (ADC). The digital signal is processed by the dedicated circuit module based on the least mean square error demodulation (LMSD) algorithm on the chip. The low-power Cortex-M3 processor supports software implementation of control algorithms and circuit parameter configuration. The control signal is output through a digital BPSDM. The chip was taped out under SMIC 180 nm Complementary Metal Oxide Semiconductor (CMOS) technology and tested for performance. The result shows that the maximum operating frequency of the chip is 105 MHz. The total area is 77.43 mm2. When the system clock is set to 51.2 MHz, the static power consumption and dynamic power consumption of the digital system are 18 mW and 54 mW respectively.

Online Nonlinear Error Compensation Circuit Based on Neural Networks

“…The dynamic power consumption of the circuit is positively related to the clock frequency. When the sampling signal is 800 kHz [2], the main clock frequency is 25.6 MHz, and the dynamic power consumption of the circuit is 1.12 mW, which meets the needs of low-power applications. In addition, the total cell area obtained from the area report is 0.19 mm 2 , in which the multiplier consumes more combinational area, which is a direction for resource optimization.…”

“…In the experiment, the window size of the moving average filter is a constant. Referring to Equation (2), is equal to 6. The MLP model was trained using the Adam optimizer [32].…”

“…MEMS inertial sensors have the characteristics of small size, low cost, and low power consumption, and are widely used in the fields of aerospace, intelligent robots, vehicles, mobile equipment, etc. [1,2]. Compared with mechanical gyros or accelerometers, fiber gyros, laser gyros, APS under the printed circuit board (PCB) process, etc., the accuracy of MEMS inertial sensors needs to be further improved to expand the application field [3].…”