Dual-Oscillator PN-CAN Clock Generation With Precision Resistor Reference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing clock generation techniques for partial-networking controller area network (PN-CAN) in vehicles face challenges in achieving high accuracy and fast clock requirements, especially during standby operation, due to insufficient accuracy and lack of reference, as well as inefficiencies in power usage and temperature drift.
Innovation Solution
An electronic circuit with a first oscillator configured to receive a reference signal and lock a frequency output, and a second oscillator to scale and maintain the frequency output, using a single external precision resistor and a remotely located microcontroller reference, effectively addressing temperature drift and power efficiency while operating within specified accuracy and frequency ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional oscillators are used for clock generation, then the system can operate during standby mode, but the accuracy deteriorates due to temperature drift and insufficient reference
Solution Approach 1:
The patent introduces an external precision resistor as an intermediary reference element that is less sensitive to temperature drift than internal oscillators. This external reference serves as a mediator between the oscillator circuit and the temperature environment, providing a more stable frequency reference during standby operation and across temperature variations.
Solution Approach 2:
The patent replaces the mechanical/physical oscillator system (which is inherently temperature-sensitive) with an electronic system that uses an external precision resistor reference. This substitution allows the clock generation to rely on an external stable reference rather than internal temperature-dependent oscillation mechanisms.
2Measurement precision
If high accuracy clock generation is implemented, then the timing requirements are met, but the power consumption increases during standby operation
Solution Approach 1:
The patent applies partial action by using the external precision resistor reference only when high accuracy is required (during standby mode with message decoding), rather than continuously operating high-power reference systems. The system selectively activates the precise clock generation path only when needed, reducing overall power consumption while maintaining timing accuracy during critical operations.
3Adaptability or versatility
If internal reference is used for clock generation, then the system is self-contained, but the accuracy deteriorates due to lack of external reference
Solution Approach 1:
The external precision resistor acts as an intermediary reference that bridges the gap between internal oscillator capabilities and external accuracy requirements. It provides the missing external reference signal during standby operation, enabling the system to maintain both self-contained operation and high frequency accuracy simultaneously.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electronic circuit includes a first pin corresponding to a reference signal and a second pin corresponding to an external resistor, the external resistor being connected on a first side to the second pin and connected on a second side to ground. The apparatus also includes a first oscillator having a first frequency loop configured to: receive, via the first pin, the reference signal; receive, via the second pin, a current associated with voltage applied to the external resistor; and lock a first frequency output at a frequency associated with the reference signal. The apparatus also includes a second oscillator having a second frequency loop configured to: receive the first frequency output; scale the frequency of the first frequency output; and lock a second frequency output at the scaled frequency of the first frequency output.