摘要
针对微加速度计接口电路的Sigma-Delta(ΣΔ)数字反馈系统,提出了一种基于脉宽调制(PWM)的力反馈回路:利用模拟低通滤波器将PWM波解调成模拟输出信号,具有滤波和数模转换功能。首先建立微加速度计ΣΔ闭环反馈系统的Simulink模型并进行了系统级仿真。之后采用Filter Solutions滤波器设计软件确定三阶低通巴特沃斯滤波器,并采用Pspice仿真软件进行电路级仿真。最后将制作的PCB版电路进行测试:PWM波通过力反馈回路能还原成高保真度的模拟信号,输出信号和输入信号的频率相对误差小于0.36%,等效DAC分辨率为8 bit。试验表明,此方案结构简单、成本低,能以较低电路复杂度实现高精度的模拟信号输出。
Aiming at the Sigma-Delta（ ∑△）digital force feedback system in Mcro-accelerometer interface circuit, this paper presents a force feedback loop based on Pulse Width Modulator （PWM）. The PWM wave can be translated into output analog singal using low pass filter,indicating that this circuit has a dual function of filter and digital to analog conversion （DAC）. Firstly, ∑△ closed loop feedback system was simulated in Simulink model for system level simulation, then Filter Solutions software was used for designing three-order Butterworth low pass filter, and Pspice software was adopted for circuit level simulation. Finally electronic circuit was made by PCB and then tested. Through the force back loop, the wave can be successfully translate to undistorted analog signal, and the maximun relative error is below 0.36% compared to the input signal,the equivalent DAC resolution is 8 bit. This experiment shows that this method has the advantages of simple structure, low cost, and easy way to produce high precise output analog signal.
出处
《传感技术学报》
CAS
CSCD
北大核心
2013年第12期1704-1709,共6页
Chinese Journal of Sensors and Actuators
基金
国家科技重大专项项目(2008ZX05008)
关键词
微加速度计
接口电路
∑△
数模转换器
脉宽调制
micro-accelerometer
sigma-delta
digital to analog converter
pulse width modulator
