Fingerprint Smart Card Frame Control for Low-Power Verification
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Solution Overview
Problem
Smart cards with fingerprint sensing systems face high power consumption issues when far from the power source, leading to insufficient electrical power for fingerprint enrollment and verification.
Innovation Solution
The smart card operates in a frame mode where the fingerprint sensing device stops sensing while the controller reads data, and vice versa, reducing simultaneous operations to lower power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the fingerprint sensing device continuously senses the fingerprint while the controller reads the data, then the working efficiency is improved, but the power consumption increases significantly
Solution Approach 1:
The patent implements periodic action by alternating between sensing phase and reading phase. During the sensing phase, the fingerprint sensing device actively senses while the controller enters sleep mode. During the reading phase, the controller reads the stored fingerprint data while the sensing device stops sensing. This periodic switching prevents simultaneous operation, thereby reducing power consumption while maintaining fingerprint enrollment and verification functionality.
2Speed
If the controller and fingerprint sensing device operate simultaneously, then the data acquisition speed is improved, but the current consumption becomes excessively high
Solution Approach 1:
The patent applies preliminary action by having the fingerprint sensing device complete the entire sensing process and store the fingerprint data in memory before the controller begins reading. The sensing device performs the sensing action in advance, stores the results, and then the controller reads the pre-stored data. This eliminates the need for simultaneous operation, reducing current consumption while ensuring complete fingerprint data is available for processing.
Data Source
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AI summary
A smart card with a fingerprint sensing system, includes a controller and a fingerprint sensing device. When the fingerprint sensing device senses a fingerprint to generate a fingerprint frame data, the controller enters a sleep mode, and when the controller reads the fingerprint frame data, the fingerprint sensing device stops sensing the fingerprint. Since operations of sensing the fingerprint and reading the fingerprint frame data do not occur at the same time, the high current condition can be avoided so as to decrease power consumption.