Dust sensor stray light component subtraction circuit and dust sensor

By designing a stray light component subtraction circuit for a dust sensor, and utilizing a smoothing circuit and a DC current application circuit, the problem of stray light interference was solved, achieving high-precision dust detection, reducing costs, and expanding the operating range of the amplifier circuit.

CN224383058UActive Publication Date: 2026-06-19YUANCHENG SCI & TECH (HENAN) CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
YUANCHENG SCI & TECH (HENAN) CO LTD
Filing Date
2025-07-03
Publication Date
2026-06-19

AI Technical Summary

Technical Problem

During the detection process, stray light interference signals from existing dust sensors cause a decrease in detection stability and accuracy, and existing measures are insufficient to effectively eliminate the influence of stray light.

Method used

Design a stray light component subtraction circuit for a dust sensor, including a smoothing circuit and a DC current application circuit. Unnecessary stray light signal components are subtracted through a final stage amplification circuit. PMOS or PNP transistors and MOS transistors are used as switching control current application and smoothing circuit input. High-precision adjustment is achieved by combining the PWM output of a microcomputer.

Benefits of technology

It effectively suppresses the effects of amplifier circuit errors and noise, expands the operating range, improves detection accuracy, reduces costs, and simplifies the circuit structure.

✦ Generated by Eureka AI based on patent content.

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Abstract

This invention discloses a stray light component subtraction circuit for a dust sensor and a dust sensor itself. The stray light component subtraction circuit for a dust sensor includes a smoothing circuit and a DC current application circuit. The smoothing circuit consists of a resistor Ra connected in series with an RC filter composed of a resistor Rb and a capacitor C1 connected in parallel, used to smooth the PWM output of a microcomputer to adjust the control voltage. The DC current application circuit consists of a resistor R2 and a transistor. The input terminal of the transistor is connected to a power supply through resistor R2. The output terminal of the transistor is connected to the signal differential node of any stage amplifier in the dust sensor's amplifier circuit, and the trigger control terminal of the transistor is connected to the output terminal of the smoothing circuit. The purpose of this invention is to eliminate the influence of stray light in the dust sensor, reduce unnecessary signal components caused by stray light, and thus improve the measurement stability and detection accuracy of the dust sensor.
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