Hou Bo, Zhou Bin, Li Xiang, Gao Zhenyi, Wei Qi, Zhang Rong
Engineering Research Center for Navigation Technology, Department of Precision Instrument, Tsinghua University, Beijing 100084, China.
Sensors (Basel). 2019 Jul 15;19(14):3116. doi: 10.3390/s19143116.
This paper presents an analog interface application-specific integrated circuit (ASIC) for a capacitive angle encoder, which is widely used in control machine systems. The encoder consists of two parts: a sensitive structure and analog readout circuit. To realize miniaturization, low power consumption, and easy integration, an analog interface circuit including a DC capacitance elimination array and switch synchronous demodulation module was designed. The DC capacitance elimination array allows the measurement circuit to achieve a very high capacitance to voltage conversion ratio at a low supply voltage. Further, the switch synchronous demodulation module effectively removes the carrier signal and greatly reduces the sampling rate requirement of the analog-to-digital converter (ADC). The ASIC was designed and fabricated with standard 0.18 µm CMOS processing technology and integrated with the sensitive structure. An experiment was conducted to test and characterize the performance of the proposed analog interface circuit. The encoder measurement results showed a resolution of 0.01°, power consumption of 20 mW, and accuracy over the full absolute range of 0.1°, which indicates the great potential of the encoder for application in control machine systems.
本文介绍了一种用于电容式角度编码器的模拟接口专用集成电路（ASIC），该编码器广泛应用于控制机器系统中。该编码器由两部分组成：一个敏感结构和模拟读出电路。为了实现小型化、低功耗和易于集成，设计了一种包括直流电容消除阵列和开关同步解调模块的模拟接口电路。直流电容消除阵列使测量电路能够在低电源电压下实现非常高的电容电压转换率。此外，开关同步解调模块有效地去除了载波信号，并大大降低了模数转换器（ADC）的采样率要求。该ASIC采用标准的0.18μm CMOS工艺进行设计和制造，并与敏感结构集成在一起。进行了一项实验来测试和表征所提出的模拟接口电路的性能。编码器的测量结果显示分辨率为0.01°，功耗为20 mW，在整个绝对范围内的精度为0.1°，这表明该编码器在控制机器系统中的应用具有巨大潜力。
