Integrated Antenna Driver Circuit for Vehicle Access Control
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Solution Overview
Problem
Existing vehicle access control and immobilizer systems face challenges in optimizing transmission power for different frequency signals, leading to increased complexity and cost when using separate antennas for low-frequency and high-frequency communications, and are prone to malfunctions due to environmental changes.
Innovation Solution
An electrical circuit with integrated antenna drivers and a receiver device on a semiconductor chip allows for independent adjustment of signal strengths and frequencies, using a diagnostic circuit for calibration and a step-up converter to optimize antenna performance, reducing component count and improving communication between systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate antennas are used for low-frequency and high-frequency communications, then transmission power can be optimized for each system, but device complexity and cost increase
Solution Approach 1:
The patent applies multi-functionality by enabling a single antenna to serve dual purposes: low-frequency communication for immobilizer systems and high-frequency communication for access control systems. The antenna is designed with matching networks that allow it to resonate at both low-frequency (e.g., 125 kHz) and high-frequency (e.g., 433 MHz) ranges, eliminating the need for separate antennas while maintaining optimized transmission performance for each frequency band
Solution Approach 2:
The patent implements dynamic switching between different frequency operations using switching elements (such as PIN diodes or transistors) that can dynamically change the antenna's resonant frequency. The matching network includes variable components that can be adjusted via control signals to switch between low-frequency and high-frequency modes, allowing the single antenna to adapt its characteristics based on the active communication protocol
2Device complexity
If the same antenna is used for both access control and immobilizer, then device complexity is reduced, but transmission power cannot be optimized for each system
Solution Approach 1:
The patent applies local quality by creating frequency-specific matching networks tailored to each operating band. The matching circuit includes separate impedance transformation paths optimized for low-frequency (with higher Q-factor for narrow bandwidth) and high-frequency (with broader bandwidth characteristics) operations. This allows each frequency band to have its own optimized impedance matching and power transfer characteristics despite sharing the same physical antenna
Solution Approach 2:
The patent implements dynamic power optimization through electronically controllable switching elements that can adjust the antenna's resonant frequency and impedance characteristics in real-time. Control circuits monitor the active protocol (access control or immobilizer) and dynamically reconfigure the matching network to maximize power transfer efficiency at the required frequency, ensuring optimal transmission power for each system
3Ease of manufacture
If antenna drivers are integrated on a semiconductor chip, then manufacturing cost is reduced, but diagnostic capability becomes more difficult
Solution Approach 1:
The patent incorporates feedback mechanisms where the receiver device monitors signals from the antenna and provides diagnostic information about antenna driver performance. The system includes test modes where the receiver measures received signal strength, frequency accuracy, and modulation quality, then feeds this information back to a control unit that can detect antenna driver malfunctions, frequency drift, or impedance mismatches, enabling diagnostics despite the integrated architecture
Solution Approach 2:
The patent implements self-service diagnostics where the antenna driver and receiver device work together to automatically detect and report their own operational status. The system includes built-in self-test functions that can measure the antenna driver's output frequency, power level, and modulation accuracy without external testing equipment, allowing the integrated circuit to diagnose its own health and report errors through standard communication interfaces
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 enables efficient power adjustment for both access control and immobilizer systems, reduces interference, and ensures reliable operation across varying conditions, while minimizing costs and space requirements.
Implementation Method 1
a first antenna driver (12) for driving a first antenna (19) for transmitting a signal in case of identifying an ID transmitter (3) for the access control of the vehicle
Implementation Method 2
a second antenna driver (24) for driving a second antenna (21) for emitting a signal in the event of identification of an ID transmitter (3) for the immobilizer of a vehicle
Implementation Method 3
a receiver device (14) for receiving a signal received from an antenna (21) for identifying an ID transmitter (3) for the immobilizer
Data Source
Figure 1
AI summary
The invention relates to an electric circuit for an access control and immobilizer of a vehicle and to a method for calibrating an antenna driver. An electric circuit for controlling the access and immobilizing a vehicle is provided. The electric circuit comprises a first antenna driver (12) for driving a first antenna (19) for emitting a signal (100) in the event of identification of an ID transmitter (3) for access control of a vehicle. A second antenna driver (24) is provided for driving a second antenna (21) for emitting a signal (104) in the event of identification of an ID transmitter (3) for the immobilizer of the vehicle. In addition, the electric circuit comprises a receiver device (14) for receiving a signal captured by an antenna (21) for the identification of an ID transmitter (3) for the immobilizer. The first antenna driver (12) and the receiver device (14) are commonly integrated into a semiconductor chip (1).