Fingerprint Recognition Wake-Up Circuit
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Solution Overview
Problem
Fingerprint recognition modules in consumer electronic devices consume significant power to maintain an operating status for timely response to user input, leading to increased power consumption.
Innovation Solution
A fingerprint recognition device with a wake-up function that includes a signal wiring, a sensing array, and a control circuit, which detects capacitance between electrodes to determine the presence of an object and switches operation modes to conserve power and generate sensing signals for image calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the fingerprint recognition module maintains operating status to respond to user input in time, then the response speed is improved, but the power consumption increases significantly
Solution Approach 1:
The fingerprint recognition module dynamically switches between wake-up mode and sleep mode based on user interaction needs. In wake-up mode, the module is fully operational for fast response; in sleep mode, it reduces power consumption while maintaining basic functionality. This dynamic state transition resolves the contradiction between maintaining fast response and reducing power consumption.
Solution Approach 2:
The control circuit periodically switches the fingerprint recognition module between wake-up mode and sleep mode. During sleep mode, the module performs periodic sensing to detect user presence, and when detected, transitions to wake-up mode for full operation. This periodic action allows the system to balance power consumption with response readiness.
2Use of energy by moving object
If the fingerprint recognition module switches to sleep mode to save power, then the power consumption is reduced, but the response time to user input increases
Solution Approach 1:
Before fully transitioning to sleep mode, the control circuit performs a wake-up detection operation using the sensing array to check for user presence. This preliminary action ensures that if a user is already touching the device, the system can immediately transition to wake-up mode without delay, thus minimizing response time while still achieving power savings during sleep mode.
Solution Approach 2:
The control circuit continuously monitors the sensing array output even in sleep mode to detect user presence. This feedback mechanism allows the system to detect when a user approaches or touches the device and immediately wake up, thereby reducing the effective response time while maintaining low power consumption during sleep mode.
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 enables power-saving and fast response capabilities by reducing power consumption during sleep mode while ensuring timely detection of user input, allowing for efficient fingerprint recognition.
Implementation Method 1
The control circuit is configured to detect capacitance between the signal wiring and the first electrode in a first operation mode to generate a sensing result, and is configured to determine whether an object is on or near the sensing array according to the sensing result
Data Source
AI summary
A fingerprint recognition device with a wake-up function is provided, which includes a signal wiring, a sensing array at least partially surrounded by the signal wiring, a first electrode, and a control circuit. The control circuit is coupled with the signal wiring, the first electrode, and the sensing array. The control circuit detects capacitance between the signal wiring and the first electrode in a first operation mode to generate a sensing result, and determines whether an object is on or near the sensing array according to the sensing result. If the control circuit determines that the object is on or near the sensing array, the control circuit switches from the first operation mode to a second operation mode. The control circuit drives the sensing array by the signal wiring to generate multiple sensing signals in the second operation mode, and calculates a sensed image according to the multiple sensing signals.