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

Abstract

The invention belongs to the field of integrated circuits, and discloses a heartbeat current signal conversion device. The heartbeat current signal conversion device comprises a converter, a mixer and a fully-differential integrator, and is characterized in that the converter is used for converting modulated light signals into current signals and transmitting out the current signals; the mixer is used for performing frequency conversion on heartbeat current signals and background light current signals in the current signals and then transmitting out the modulated light current signals, the frequency converted heartbeat current signals and the frequency converted background light current signals in the current signals; and the fully-differential integrator is used for performing positive integration and negative integration on the inputted modulated light current signals, the frequency converted heartbeat current signals and the frequency converted background light current signals and then outputting voltage signals. The fully-differential integrator provided by the embodiment of the invention can improve suppression of the heartbeat current signal conversion device for common-mode noise, the linearity and the output dynamic range. In addition, a loop of the heartbeat current signal conversion device always forms a closed loop, thereby being capable of directly outputting for a lower-level circuit, saving an output buffering circuit, and thus reducing the 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...

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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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