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提出一种用于巨磁阻(GMR)生物传感器检测的模拟前端电路。电路采用电压检测的方法,包括基准电压源,单位增益缓冲器,电荷转移型开关电容采样保持电路,流水线模数转换器四部分;基准电压源用于产生传感器阵列的片内激励电压;传感器阵列的检测输出电压经单位增益缓冲器后,由开关电容采样保持电路进行采样,保持,放大;最后经过流水线模数转换器输出数字码流;芯片采用SMIC 0.18μm 1P6M CMOS厚栅氧工艺实现。测试结果表明,在电源电压3.3 V,20 MHz时钟下测试,整体电路输出信号有效精度达到7.2 bit,功耗33 mW,满足GMR生物传感器的检测要求。
An analog front-end circuit for giant magnetoresistive (GMR) biosensor detection is proposed. The circuit adopts voltage detection method, including four parts of a reference voltage source, a unity gain buffer, a charge-transfer switch capacitor sample-and-hold circuit and a pipeline ADC. The reference voltage source is used to generate an on-chip excitation voltage of the sensor array. Of the detection output voltage by the unit gain buffer, the switch capacitor sample-and-hold circuit to sample, maintain, enlarge; Finally, after the digital-analog converter streamline output stream; chip SMIC 0.18μm 1P6M CMOS thick gate oxide technology. The test results show that the overall circuit output signal accuracy of 7.2 bit, 33 mW power consumption, meet the detection requirements of GMR biosensors tested under the supply voltage of 3.3 V, 20 MHz clock.