Physiological signal conditioning circuit and physiological signal acquisition system

The invention provides a physiological signal conditioning circuit and a physiological signal acquisition system. The physiological signal conditioning circuit comprises a first amplifying circuit, a DC cancellation circuit, a second amplifying circuit and a charge retention circuit which are sequentially connected. The input end of the first amplifying circuit is connected to the output end of a physiological signal detection module. The output end of the charge retention circuit is connected to the input end of an ADC (analog-to-digital converter). The physiological signal detection module is used for detecting a to-be-detected object and for outputting a physiological signal. According to the physiological signal conditioning circuit and the physiological signal acquisition system provided by the invention, a subsequent ADC effective sampling time is greatly prolonged due to the charge retention circuit, so that high-resolution and high-precision analog-to-digital conversion is achieved, and meanwhile power consumption is reduced.