Capacitance Detection Circuit Without ADC for Low-Power Sensing
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Solution Overview
Problem
Current capacitance detection circuits rely on analog circuits, including analog-to-digital converters, which consume high power and incur significant costs, and lack effective anti-interference capabilities.
Innovation Solution
A capacitance detection circuit that digitizes capacitance without an analog-to-digital converter by using a capacitance control module to charge and discharge a capacitor multiple times, generating a digital voltage signal, and a filter module to calculate capacitance, thereby simplifying the circuit structure and reducing power consumption while enhancing anti-interference capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an analog-to-digital converter is used for capacitance detection, then measurement precision is improved, but power consumption increases and device complexity increases
Solution Approach 1:
The patent extracts and removes the analog-to-digital converter from the capacitance detection circuit, replacing it with a purely digital detection approach using a capacitance control module that directly generates digital voltage signals through multiple charge-discharge cycles, thereby eliminating the power-consuming ADC component while maintaining detection precision
Solution Approach 2:
The patent substitutes the analog signal processing mechanism (ADC) with a digital signal generation mechanism (capacitance control module performing repeated charge-discharge operations), replacing the analog-to-digital conversion process with a direct digital signal generation process that counts charge cycles to determine capacitance values
2Measurement precision
If an analog-to-digital converter is used for capacitance detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent removes the analog-to-digital converter from the circuit structure, simplifying the overall device architecture by eliminating this complex analog component and replacing it with a more straightforward digital control and signal generation system
Solution Approach 2:
The patent replaces the complex analog signal chain with a digital signal generation approach, where the capacitance control module directly produces digital voltage signals through programmed charge-discharge cycles, eliminating the need for analog filtering, amplification, and conversion stages
3Reliability
If charge and discharge cycles are increased to improve anti-interference ability, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent employs periodic charge-discharge cycles performed by the capacitance control module, where multiple repeated cycles are executed to accumulate statistical data and filter out interference signals, with the periodic nature allowing for systematic error reduction while maintaining efficient detection timing
Solution Approach 2:
The patent performs preliminary charge-discharge operations to establish baseline measurements and filter interference before final capacitance determination, using the initial cycles to prepare the system state and eliminate transient effects that could affect measurement reliability
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
This approach enables a simple circuit structure with reduced power consumption and cost, while improving the anti-interference ability of the capacitance detection circuit by increasing charge and discharge cycles.
Implementation Method 1
a capacitance control module, configured to control a capacitor to be detected to be charged and discharged for multiple times, and generate a digital voltage signal according to an amount of received charges
Implementation Method 2
in response to the digital voltage signal being at a high level, the charge conversion module is configured to output negative charges with a preset charge amount to the capacitance control module
Data Source
AI summary
A capacitance detection circuit is provided, which includes a capacitance control module, a charge conversion module and a filter module connected with each other. The capacitance control module controls a capacitor to be charged/discharged for multiple times and generates a digital voltage signal according to an amount of received charges. The capacitor releases all stored charges after being charged to a preset voltage during each charge/discharge. In response to the digital voltage signal being at a high level, the charge conversion module outputs negative charges with a preset charge amount to the capacitance control module. The preset charge amount is greater than or equal to an amount of the stored charges when the capacitor is charged to the preset voltage. The filter module obtains a value representing a capacitance of the capacitor according to the digital voltage signal.