Key Fob Inductive Backup Power Without Separate Communication Circuit
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Solution Overview
Problem
Current backup communication devices for electronic control keys (key fobs) are complex, expensive, and require significant development time due to the need for separate microcontrollers, flash memory, and compliance tests for each communication interface.
Innovation Solution
A key fob system that uses an inductive link to provide power to the primary circuitry without performing communications, simplifying the circuitry and eliminating the need for a separate backup communication device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate backup communication device with microcontroller and flash memory is used, then backup functionality is achieved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the backup communication functionality with the primary communication circuit by using the same microcontroller and communication hardware for both primary and backup operations. The system switches between battery power and inductive power sources while maintaining a single unified communication circuit, eliminating the need for separate backup communication devices and reducing overall system complexity.
Solution Approach 2:
The communication circuit is designed to serve multiple functions: it operates as the primary communication interface when battery power is available, and automatically serves as the backup communication interface when inductive power is detected. This multi-functional design allows the same hardware to fulfill both primary and backup roles, reducing component count and simplifying the system architecture.
2Reliability
If separate backup communication circuitry is implemented, then backup functionality is ensured, but manufacturing cost increases
Solution Approach 1:
The patent combines backup communication functionality with the existing primary communication circuit, eliminating the need for duplicate hardware components. By using the same microcontroller, communication transceiver, and antenna for both primary and backup operations, the system reduces component count, simplifies assembly processes, and lowers manufacturing costs while ensuring backup functionality through software-controlled power source switching.
Solution Approach 2:
Instead of creating a physical copy of the communication circuit for backup purposes, the patent uses software logic to enable the existing communication circuit to function as backup. The system detects inductive power presence and activates the communication circuit for backup operations without requiring duplicate hardware, thereby reducing manufacturing complexity and cost.
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 solution reduces the complexity and cost of key fob manufacturing, streamlines development time, and avoids the need for radio equipment compliance tests, while ensuring continued functionality even when the battery is dead.
Implementation Method 1
An inductive element may be provided on the key fob that inductively links with the access control system to establish an inductive power and communication link
Data Source
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AI summary
A key fob including at least one wireless communication circuit, a power supply node coupled to provide power to the at least one wireless communication circuit, a battery node, a battery power circuit, and an inductive power circuit. The battery power circuit provides power when a battery with sufficient charge is provided. The inductive power circuit only provides power when energized with inductive power when the battery is not provided or is not sufficiently charged. The inductive power circuit may include a rectifier circuit and an inductor and may further include regulator circuitry. The inductive power circuit does not perform wireless communications thereby simplifying circuitry and operation of the key fob and a corresponding access system. Since only configured to transfer power, the inductive power circuit may be optimized for power transfer. The access system inductively couples power to the key fob when within a predetermined coupling zone distance.