Pressure Detecting Circuit Frequency Oscillation Leakage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Piezoresistive detection circuits suffer from current leakage and large detection errors due to high on-state resistance of thin film transistors and excessive power consumption.
Innovation Solution
A pressure detecting circuit comprising a pressure sensing circuit, a signal generating circuit, and a frequency detecting circuit that forms an oscillating circuit, where the signal generating circuit produces an oscillating signal based on pressure sensed by the pressure sensing circuit, and the frequency detecting circuit determines pressure by measuring the frequency of this signal, improving noise resistance and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a passive piezoresistive detection circuit is used to detect piezo-resistance after coupling to an amplifier in a normally open state, then the detection can be performed, but current leakage occurs and detection error increases due to large on-state resistance of thin film transistors
Solution Approach 1:
The patent employs periodic action by using a scanning signal to periodically select and activate specific piezoresistive sensor rows. Instead of keeping all sensors continuously connected (which causes current leakage), the system activates only the selected row during each scanning period, thereby reducing overall current leakage while maintaining detection capability through time-division multiplexing.
Solution Approach 2:
The patent extracts the detection function from continuous operation by separating the scanning selection process from the signal reading process. The scanning signal line selectively connects to specific sensor rows, effectively extracting and isolating only the necessary sensors for detection at any given time, which reduces current leakage in unselected sensor paths.
2Measurement precision
If a passive piezoresistive detection circuit with large on-state resistance thin film transistor is used, then the circuit can operate, but the current signal change is too small leading to large detection error
Solution Approach 1:
The patent introduces an intermediary approach by using a dedicated reading signal line that connects to the selected piezoresistive sensor row through a low-impedance path. This intermediary connection path reduces the overall circuit resistance during detection, allowing sufficient current to flow through the sensor and improving the current signal magnitude for accurate detection.
Solution Approach 2:
The patent applies dynamics by making the circuit configuration changeable through the scanning signal. The connection state of sensor rows is dynamically switched from disconnected to connected based on the scanning signal, allowing the system to optimize the electrical path for detection and improve current signal magnitude when needed.
3Measurement precision
If an active piezoresistive detection circuit is used, then detection can be performed with lower error, but a large amount of current is consumed
Solution Approach 1:
The patent uses periodic action through scanning signals to activate sensor rows only when needed for detection. This time-division multiplexing approach reduces overall power consumption compared to continuous activation, while maintaining detection precision through systematic scanning of all sensor rows.
Solution Approach 2:
The patent applies partial action by activating only the necessary portion of sensors (selected rows) at any given time rather than all sensors simultaneously. This partial activation reduces total current consumption while maintaining detection capability through sequential scanning of individual rows.
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 reduces detection errors and power consumption by using frequency as a detection index, allowing for precise pressure sensing without external excitation.
Implementation Method 1
a pressure sensitive component FR, a first transistor G1, and a first capacitor C1
Data Source
AI summary
A pressure detecting circuit may include a pressure sensing circuit (101), a signal generating circuit (102), and a frequency detecting circuit (103). The pressure sensing circuit (101) and the signal generating circuit (102) may be configured to constitute an oscillating circuit (104). The signal generating circuit (102) may be configured to generate an oscillating signal based on a pressure sensed by the pressure sensing circuit (101). The frequency detecting circuit (103) may be configured to detect a frequency of the oscillating signal and determine a value of the pressure sensed by the pressure sensing circuit (101) based on the frequency of the oscillating signal.