Conversion circuit, heartbeat current signal conversion device and method, and heartbeat detection system

Abstract

A heartbeat current signal conversion device, comprising a converter for converting a modulated optical signal into a current signal and transmitting same; a mixer for performing frequency conversion of a heartbeat current signal and a background photocurrent signal in the current signal, and then transmitting the modulated photocurrent signal, the frequency-converted heartbeat current signal and the frequency-converted background photocurrent signal in the current signal; a fully differential integrator for performing both positive integration and inverse integration on the modulated photocurrent signal, the frequency-converted heartbeat current signal and the frequency-converted background photocurrent signal, which are inputted, and then outputting a voltage signal. The fully differential integrator can improve the suppression of the heartbeat current signal conversion device to the common mode noise, and the linearity and the dynamic output range of the circuit. Moreover, the heartbeat current signal conversion device loop always forms a closed loop, and thus a direct output to the next-stage circuit can be achieved, eliminating an output buffer circuit, thereby reducing power consumption.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, and in particular relates to a conversion circuit, a heartbeat current signal conversion device and conversion method, and a heartbeat detection system. Background technique [0002] In the photoelectric heartbeat detection system, the conversion circuit is one of the core parts. Its function is to down-convert the heartbeat current signal modulated on the clock frequency to zero frequency, and then convert the heartbeat current signal into a voltage signal through a transimpedance amplifier. , and then sent to the subsequent circuit for processing. Therefore, the performance of the conversion circuit such as power consumption, noise, linearity, and output dynamic range seriously restricts the performance of the entire heartbeat detection system. The current conversion circuit generally has two forms: single-ended and first mixed and then integrated. [0003] If a single-ended conve...

AI Technical Summary

Problems solved by technology

[0006] In view of this, the technical problem to be solved by the present invention is to provide a conversion circuit, a heartbeat current signal conversion device and conversion method, and a heartbeat detection system, which are used to solve the noise caused by the large transimpedance existing in the existing heartbeat current signal conversion circuit, Problems of common mode noise interference, small working dynamic range, and poor linearity

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