Wheel Sensor Interface Circuit for Current Signal Detection
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Solution Overview
Problem
Existing wheel sensor interface circuits struggle to accurately sense distortions and abnormalities in the original signal from wheel sensors, as they convert and amplify current values into voltage, making it difficult to detect intrinsic signal anomalies.
Innovation Solution
A wheel sensor interface apparatus that includes a wheel sensor interface unit to supply power and sense output current, and an over-current detection unit with a reference current generation unit and voltage level decision unit, allowing the microprocessor to determine if the output current is normal or over-current by analyzing voltage levels, thereby directly sensing and processing the intrinsic current signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated wheel sensor interface circuit with operational amplifier is used to convert current to voltage, then the circuit can interface with ECU/MCU, but it cannot accurately sense distortion and abnormality of the original current signal
Solution Approach 1:
The patent divides the signal processing function into two separate units: the wheel sensor interface unit that directly senses and transmits the current signal, and the over-current detection unit that monitors for abnormalities. This segmentation allows the original current signal to be preserved for accurate sensing while enabling separate monitoring of signal distortions and abnormalities without interference from voltage conversion operations.
Solution Approach 2:
The patent introduces a current mirror circuit as an intermediary between the wheel sensor and the detection circuitry. This current mirror faithfully reproduces the original current signal without converting it to voltage, allowing the microprocessor to directly analyze the intrinsic current characteristics and detect distortions or abnormalities while maintaining signal integrity.
2Ease of operation
If the wheel sensor interface circuit converts current value to voltage using pull-down resistor and operational amplifier, then the signal can be read by ECU, but the intrinsic current value and its abnormalities cannot be directly read
Solution Approach 1:
The patent separates the signal transmission function from the monitoring function. The wheel sensor interface unit handles current-to-voltage conversion for ECU compatibility, while the over-current detection unit independently monitors the original current signal through a current mirror, enabling both readable output and precise current measurement simultaneously.
Solution Approach 2:
The patent creates a copy of the original current signal using a current mirror circuit. This copy allows the microprocessor to analyze the intrinsic current characteristics and detect abnormalities without affecting the main signal path that converts current to voltage for ECU reading, thus preserving measurement precision while maintaining ease of operation.
3Ease of manufacture
If a conventional wheel sensor interface circuit is designed for specific automobile makers, then it can interface with those vehicles, but it lacks adaptability to recognize various types of wheel sensors (active/passive/PWM/VDA)
Solution Approach 1:
The patent implements a universal wheel sensor interface circuit that can recognize and interface with multiple types of wheel sensors (active, passive, PWM, VDA) through a standardized current-based detection mechanism. The current mirror and direct current sensing approach works across different sensor types without requiring dedicated circuits for each automobile maker or sensor type, thereby achieving multi-functionality and broad adaptability.
Data Source
AI summary
A wheel sensor interface apparatus may include: a wheel sensor interface unit configured to supply power to a wheel sensor of a vehicle, or sense an output current of the wheel sensor and transmit the sensed current to a microprocessor unit of the vehicle; and an over-current detection unit including: a reference current generation unit configured to generate a reference current using a voltage across a resistor through which the output current flows; and a voltage level decision unit configured to decide a voltage level according to the reference current. The over-current detection unit may determine whether the output current is an over-current, according to the voltage level.