Heartbeat Detection Conversion Circuit for Background Current Elimination
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Solution Overview
Problem
Existing heartbeat detection circuits are affected by background light and have high power consumption due to their inability to effectively eliminate background photoelectric current and base current, leading to reduced accuracy and increased noise in heartbeat signal detection.
Innovation Solution
A conversion circuit that includes current eliminating circuits to remove background and base currents, an integrating circuit to isolate the heartbeat current, and noise suppression capacitors to reduce noise and power consumption, thereby enhancing detection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a transimpedance amplifier is used to convert photoelectric current to voltage signal, then the conversion function is achieved, but the background photoelectric current cannot be eliminated and power consumption is high
Solution Approach 1:
The patent segments the photoelectric current into three components: background photoelectric current, base current, and heartbeat current. By using separate current eliminating circuits for the first two components and an integrating circuit for the heartbeat current, the system achieves precise elimination of interference currents while maintaining low power consumption and high detection accuracy.
2Reliability
If a transimpedance amplifier is used to convert photoelectric current, then conversion is achieved, but it is easy to be impacted by noise
Solution Approach 1:
The patent extracts and eliminates the noise-containing components (background photoelectric current and base current) from the total photoelectric current before integration. By removing these interfering components through dedicated eliminating circuits, the heartbeat current can be integrated with minimal noise impact, significantly improving detection reliability.
3Measurement precision
If existing heartbeat detection circuit is used, then basic detection function is achieved, but detection accuracy is reduced due to background light impact
Solution Approach 1:
The patent converts the harmful background photoelectric current into a measurable and eliminable component. By explicitly measuring and then eliminating the background current through a dedicated circuit, the system transforms this harmful interference into a controllable parameter that can be completely removed, thereby improving detection accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively isolates the heartbeat current from background and base currents, improving detection accuracy and reducing power consumption and noise in heartbeat detection circuits.
Implementation Method 1
The light penetrating through or reflected from the human body is sensed by using a photodiode or a phototransistor, and an optical signal (that is, a photoelectric current) sensed by the photodiode
Data Source
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AI summary
Some embodiments of the present invention provide a conversion circuit for converting a current signal into a first output voltage signal, where the current signal flows through a sensing component. The conversion circuit includes: a first current eliminating circuit, configured to eliminate a first current in the current signal, the first current eliminating circuit including: a current sample and hold circuit; and a current driving circuit, coupled between the sensing component and the current sample and hold circuit; a second current eliminating circuit, coupled to the sensing component and configured to eliminate a second current in the current signal; and an integrating circuit, coupled to the sensing component and configured to integrating for a third current in the current signal, and output a first input voltage signal between a first integration output terminal and a second integration output terminal. According to some embodiments of the present invention, a background photoelectric current and a base current in the current signal may be eliminated, and integration may be carried out for a heartbeat current in the current signal by using the integrating circuit, such that the impacts caused by the background photoelectric current and the base current to the heartbeat current are removed, and the detection efficiency is improved.