Multi-Level Differential Driver Timing for Common-Mode Noise
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Solution Overview
Problem
Existing transmission devices face challenges in suppressing common mode noise, especially when transmitting differential signals with multiple signal levels, as fixed timing adjustments are insufficient to effectively manage noise across all transition states, leading to communication performance issues.
Innovation Solution
A transmission device with a driver circuit and timing adjustment circuits that dynamically adjust input timing based on transition states of output signals, using a control circuit to change timing setting signals for each timing adjustment circuit to optimize signal levels and reduce common mode noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed timing adjustment value is used in the timing adjustment circuit, then the circuit structure remains simple, but common mode noise cannot be effectively suppressed across all transition states of multi-level differential signals
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed timing adjustment value to a variable timing adjustment value that changes according to the transition state of the differential signal. The timing adjustment circuit now dynamically selects appropriate timing values based on whether the signal is transitioning between adjacent levels or non-adjacent levels, allowing optimal noise suppression for each transition state while maintaining circuit feasibility through controlled variability.
Solution Approach 2:
The patent implements parameter changes by modifying the timing adjustment value parameter based on the transition state of the differential signal. The control circuit changes the timing adjustment parameter to different values corresponding to different transition states (adjacent vs. non-adjacent levels), enabling the system to adapt timing parameters to specific operational conditions and effectively suppress common mode noise across all transition scenarios.
2Adaptability or versatility
If the number of transition states of differential signal levels increases (e.g., four or more values), then the signal carrying capacity improves, but suppressing common mode noise in all transition states becomes difficult with fixed timing adjustment
Solution Approach 1:
The patent applies dynamics by making the timing adjustment value adaptive to the specific transition state rather than fixed. The control circuit dynamically determines the appropriate timing adjustment value based on the transition state (adjacent or non-adjacent levels), enabling the system to handle multiple signal levels effectively while maintaining optimal noise suppression for each transition scenario.
Solution Approach 2:
The patent implements parameter changes by modifying the timing adjustment parameter according to the transition state of the differential signal. When the signal transitions between adjacent levels, one timing value is applied; when transitioning between non-adjacent levels, a different timing value is applied. This parameter adaptation enables effective noise suppression across all transition states of multi-level signals.
3Measurement precision
If timing adjustment is applied to all driver input signals, then signal timing accuracy improves, but the control circuit complexity increases
Solution Approach 1:
The patent applies local quality by providing different timing adjustment values to different driver input signals based on their specific transition states. Rather than applying a uniform timing adjustment to all signals, the control circuit selectively adjusts timing for each signal according to whether it is transitioning between adjacent or non-adjacent levels, achieving high timing accuracy for each signal while avoiding unnecessary complexity in the control circuit.
Data Source
AI summary
A transmission device according to the present disclosure includes: a driver circuit that includes a plurality of output circuits each including a plurality of transistors, and outputs a plurality of output signals from the plurality of output circuits on a basis of a plurality of driver input signals being respectively inputted to the plurality of transistors, the plurality of output signals configuring a differential signal and having signal levels that are different from each other; a plurality of timing adjustment circuits that each adjusts, on a basis of a timing setting signal, an input timing of corresponding one of the plurality of driver input signals to the driver circuit; and a control circuit that changes a set value of the timing setting signal for each of the plurality of timing adjustment circuits to a value corresponding to a plurality of transition states of possible signal levels of each of the plurality of output signals to be outputted from the driver circuit.