RC-Locked VCO Circuit for Symmetrical High-Frequency CAN Timing
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Solution Overview
Problem
Current systems face challenges in generating symmetrical high-frequency timing signals for Controller Area Network (CAN) communications, leading to undesired electromagnetic radiation due to voltage spikes and phase differences, which affect data integrity and energy efficiency.
Innovation Solution
A timing circuit that locks a voltage-controlled oscillator (VCO) to high frequencies using a digital filter and adjustable current converter, with a digital-to-analog converter and logic control circuit to adjust the control signal, enabling the generation of high-frequency signals with minimal interruption and precise center frequency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional oscillators are used to generate high frequency timing signals, then frequency requirements can be met, but the signals become asymmetrical causing voltage spikes and electromagnetic radiation
Solution Approach 1:
The patent implements a feedback mechanism using an RC timing circuit that continuously monitors the VCO output frequency and adjusts the control voltage to maintain the desired frequency. The RC circuit generates a reference timing signal that is compared with the VCO output, and the difference is used to correct frequency deviations, ensuring symmetrical waveforms and eliminating voltage spikes that cause electromagnetic radiation.
Solution Approach 2:
The patent changes the operating parameters of the VCO by using an adjustable current converter controlled by a digital-to-analog converter. This allows precise adjustment of the VCO's control voltage to achieve the optimal frequency point where symmetrical output is obtained, thereby eliminating asymmetrical voltage spikes and reducing electromagnetic radiation while maintaining high frequency operation.
2Stability of the object's composition
If external oscillators or phased-lock loops are used to achieve high frequency timing signals, then frequency stability can be improved, but device complexity increases
Solution Approach 1:
The patent implements a self-service mechanism where the VCO circuit automatically adjusts its own frequency by using an integrated RC timing circuit and digital control system. The system monitors its own output and performs self-correction through the adjustable current converter and digital-to-analog converter, eliminating the need for external oscillators or complex phased-lock loops while maintaining frequency stability.
Solution Approach 2:
The patent merges multiple functions into a single integrated circuit system. The RC timing circuit, VCO, adjustable current converter, and digital control elements are combined into one unified structure that performs both frequency generation and frequency stabilization functions, thereby reducing device complexity while maintaining frequency stability.
3Object-generated harmful factors
If signal shaping time is increased to reduce electromagnetic radiation, then signal symmetry improves, but data rate decreases
Solution Approach 1:
The patent applies preliminary action by pre-shaping the timing signal waveform using the RC circuit before it reaches the VCO. The RC circuit generates a smoothly varying control voltage that prevents abrupt transitions, thereby eliminating voltage spikes and electromagnetic radiation without requiring additional signal shaping time during data transmission, thus maintaining high data rates.
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
The solution effectively generates symmetrical high-frequency timing signals, reducing electromagnetic radiation and improving data integrity by maintaining a stable center frequency, thus enhancing the efficiency of CAN communications.
Implementation Method 1
an RC timer operable to generate a time signal
Implementation Method 2
a voltage controlled oscillator (VCO) operable, when in an "ON" state, to receive the control signal and output a high frequency signal
Data Source
AI summary
Circuits and processes for locking a voltage-controlled oscillator (VCO) at a high frequency signal are described. A circuit may include a voltage-controlled oscillator configured to generate a high frequency signal based on a control signal, a dummy load parallel to the voltage-controlled oscillator and configured to receive the control signal via a switch, and a digital-to-analog converter coupled to the voltage-controlled oscillator where the control signal is generated based on an output of the digital-to-analog converter.