CAN Receiver Circuit with Common-Mode Sensing for Wide Input Range
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Solution Overview
Problem
Controller Area Network (CAN) receiver circuits face challenges in handling wide input common mode voltage ranges due to significant ground voltage shifts in vehicular environments, particularly with the increasing output voltage levels in electric vehicles, requiring improved common mode input voltage ranges while minimizing electromagnetic emission.
Innovation Solution
A receiver circuit with input common mode voltage sensing, comprising a resistor assembly, a common mode voltage sensor, and a receiving amplifier, which generates and outputs a sense output voltage to handle differential signals across a wide common mode voltage range (-50V to +50V) without increasing circuit complexity or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional receiver circuits are used, then the circuit design is simple, but the common mode input voltage range is limited and cannot handle wide voltage ranges in vehicular environments
Solution Approach 1:
The receiver circuit is segmented into three functional modules: a resistor assembly for voltage division, a common mode voltage sensor for detection, and a receiving amplifier for signal amplification. This segmentation allows each module to perform its specific function efficiently, enabling the circuit to handle wide common mode voltage ranges while maintaining manageable complexity through modular design.
Solution Approach 2:
A common mode voltage sensor is introduced as an intermediary component between the resistor assembly and the receiving amplifier. This sensor detects the common mode voltage and provides feedback to control the amplification process, enabling the circuit to adapt to wide voltage ranges without requiring a completely complex redesign of the amplifier stage.
2Adaptability or versatility
If the common mode input voltage range is expanded to handle ground voltage shifts, then the receiver can operate in vehicular environments, but electromagnetic emission increases
Solution Approach 1:
The common mode voltage sensor provides continuous feedback about the common mode voltage level to the receiving amplifier. This feedback mechanism allows the amplifier to adjust its operation dynamically, maintaining stable amplification across wide voltage ranges while minimizing electromagnetic emissions by avoiding unnecessary high-frequency fluctuations on the common mode signals.
Solution Approach 2:
The circuit dynamically adjusts its operating parameters based on the detected common mode voltage. The resistor assembly divides the wide voltage range into manageable segments, and the receiving amplifier adjusts its gain and operating point accordingly, enabling the circuit to handle ground voltage shifts from 12V to 48V systems while maintaining low electromagnetic emission through optimized parameter selection at each voltage level.
3Duration of action of moving object
If batteries with higher output voltage are applied, then longer battery life is achieved, but ground voltage shift increases and common mode input voltage range must be improved
Solution Approach 1:
The receiver circuit is designed with dynamic adaptation capability through the common mode voltage sensor and feedback mechanism. As battery voltage increases from 12V to 48V systems, the sensor detects the changed common mode voltage and the receiving amplifier dynamically adjusts its operation to maintain proper signal reception. This dynamic design allows the same circuit to accommodate different battery voltages and extend battery life without requiring separate receiver designs for different voltage systems.
Data Source
AI summary
A receiver circuit with input common mode voltage sensing is provided. The receiver circuit is applied to a controller area network and comprises a resistor assembly, connected with a high end and a low end of the controller area network, a common mode voltage sensor and a receiving amplifier. The resistor assembly bucks voltage, respectively generating the high end and low end voltage divisions at first and second nodes and outputting the voltage divisions to the receiving amplifier to generate a resultant signal to an output end of the controller area network. The common mode voltage sensor is connected between the resistor assembly and the receiving amplifier, and able to sense the common mode voltage on bus and control the voltage on center tap of the resistor assembly so the receiver circuit for controller area network can receive the differential signal with a much wider input common mode range.