为了避免透射式测量系统的高功耗、大噪声的问题,设计一种CMOS集成电路用于测量脉搏和血氧饱和度(SpO2).根据光子扩散传输理论得到反射式SpO2测量公式,以此公式为模型设计测量电路.测量电路由放大电路和带通滤波电路两大部分组成,经过测量电路的处理之后,得到脉搏波的直流量和交流量.采用UMC 0.18 μm的标准CMOS工艺实现电路,该电路仿真的各项参数为:在1.8 V的工作电压下整个系统的增益可达到42~50 dB(0.2~65 Hz),整个电路的功耗小于0.3 mW.因此,本文设计的测量电路增益达到要求,而且噪声和功耗更小,更能达到便携式医疗设备的发展要求.
In order to avoid the high power consumption and large noise of the transmission measurement system,a CMOS integrated circuit to measure the pulse and blood oxygen saturation is designed. The measurement circuit is composed of two parts:the amplifier circuit and the band-pass filter circuit.After the processing of the measured circuit,the DC quantity and AC quantity of the pulse wave are obtained.Using CMOS standard of UMC 0.18 μm process,the circuit simulation of the parameters are as follows.With the operating voltage of 1.8 V,the gain of the whole system can reach 42-50 dB, the power consumption of the whole system is less than 0.3 mW. Therefore,the gain of the measurement circuit achieves the requirements,and noise and power consumption are smaller,more able to achieve the development of portable medical equipment requirements.