Transceiver Circuit Signal Edge Detection for Bus Reflection Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bus networks, particularly those using CAN and CAN FD protocols, face limitations in data transmission rates due to signal reflections and ringing, which degrade signal quality and reduce maximum achievable data rates, especially in high-speed applications with varying node distances and cable lengths.
Innovation Solution
A transceiver circuit that switches from a dominant to a recessive communication mode by detecting signal edges, controlling output impedance within a predefined range during voltage transitions, and driving differential driver voltages to override or precondition thresholds, thereby reducing reflections and improving signal symmetry and throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the data transmission rate is increased in bus networks, then productivity is improved, but signal reflections and ringing occur which degrade signal quality
Solution Approach 1:
The transceiver circuit performs preliminary action by detecting the signal edge of the input signal before the actual mode transition occurs. This early detection allows the circuit to prepare for the transition in advance, controlling the output impedance and driving the differential driver voltage to override or precondition thresholds, thereby minimizing reflections and ringing that would otherwise occur during high-speed transitions.
2Productivity
If the data transmission rate is increased, then productivity is improved, but signal reflections cause noise that reduces maximum achievable data rates
Solution Approach 1:
The transceiver circuit applies preliminary anti-action by detecting the signal edge in advance and preemptively controlling the output impedance and differential driver voltage to counteract the effects of reflections. By driving the voltage to override or precondition thresholds before the transition completes, the circuit prevents reflections and ringing from occurring, thereby eliminating the harmful effects that would otherwise limit data rates.
3Adaptability or versatility
If nodes are located at varying distances from terminating impedances, then adaptability is improved, but reflections and ringing occur that reduce maximum data rate
Solution Approach 1:
The transceiver circuit performs preliminary action by detecting the signal edge of the input signal before the actual mode transition occurs. This early detection allows the circuit to prepare for the transition in advance, controlling the output impedance and driving the differential driver voltage to override or precondition thresholds, thereby minimizing reflections and ringing that would otherwise occur during high-speed transitions in networks with varying node distances.
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
Embodiments in accordance with present disclosure are directed to methods, devices, and apparatuses. An example embodiment includes an apparatus comprising a differential data bus and a transceiver circuit. The transceiver circuit includes a differential driver and differential receiver that operate and communicate in the first communication mode and the second communication mode. The transceiver circuit is configured to switch to the second communication mode in response detecting a signal edge of a signal input received at the differential driver by at least one of: the differential driver being configured and arranged to drive a differential driver voltage on the differential data bus to a voltage that overrides a predefined voltage; and pre-conditioning the differential receiver for the transition to the second communication mode.