基于高频调制的霍尔传感器读出电路设计

The Design of Hall Sensor Readout Circuit Based on High Frequency Modulation

本文基于霍尔传感器输出信号幅度小、频率低、易受噪声干扰的特点,有针对性地提出一种基于高频调制方式实现的霍尔传感器读出电路.该读出电路主要包括可变增益运算放大器,高频调制电路以及1 bit量化的二阶sigma-delta模数转换器.通过采用高频调制,减少电路中低频噪声以及失调的影响,同时经过放大器进行幅值放大,避免噪声混入.首先通过MATLAB建模仿真确定设计所需参数,然后基于SMIC 0.18 μm混合信号CMOS工艺完成整体电路设计.经测试,电路在3.3V电源电压,1 kHz信号带宽以及256 kHz时钟频率下,经过后仿真得到信噪比(SNR)为83.12 dB,可满足设计的要求.

To solve the problem of low amplitude,low frequency,and easy to be interfered by noise in Hall sensor output signal,this paper proposes a Hall sensor readout circuit based on high-frequency modulation. The readout circuit mainly includes a variable gain operational amplifier,a high frequency modulation circuit,and a 1-bit quantized second-order sigma-delta analog-to-digital converter. With high-frequency modulation,the effect of low-frequency noise and offset in the circuit is reduced and amplitude amplification is performed by the amplifier to keep off the noise. This paper first determines the design parameters through MATLAB modeling and simulation and then completes the overall circuit design based on the SMIC 0. 18μm mixed-signal CMOS process. The test show that the circuit has a signal-to-noise ratio( SNR) of 83. 12 dB after a 3. 3 V supply voltage,1 kHz signal bandwidth,and 256 kHz clock frequency,which can meet the design requirements.