One-Sided Transmitter Equalization With Selective Deemphasis
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Solution Overview
Problem
Conventional equalizers for high-speed serial links are complex, occupy large areas, and consume excessive power, limiting the performance and reliability of serializer/deserializer circuits.
Innovation Solution
An equalizer is introduced in a transmitter that provides one-sided deemphasis to driver circuits, using a delay element and logic circuit to enable equalizer segments based on precursor signals, reducing power consumption and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional equalizers are used to reduce errors in received data, then signal quality is improved, but power consumption increases excessively
Solution Approach 1:
The driver circuit is divided into multiple driver segments, each with its own equalizer segment. Only the necessary equalizer segments are activated based on the precursor signal, allowing selective equalization that reduces overall power consumption while maintaining signal quality where needed.
Solution Approach 2:
The equalizer segments are activated in advance based on the precursor signal (delayed version of the input signal) before the actual data transition occurs. This preliminary action allows the equalizer to prepare and reduce channel losses proactively, improving signal quality while controlling power usage through selective activation.
2Reliability
If conventional equalizers are used to reduce errors in received data, then signal quality is improved, but circuit complexity increases
Solution Approach 1:
The equalizer is segmented into multiple independent equalizer segments corresponding to different driver segments. This modular structure reduces overall circuit complexity by allowing individual segments to be activated only when needed, rather than requiring a fully active complex equalizer for all conditions.
Solution Approach 2:
The equalizer segments are dynamically activated or deactivated based on the state of the precursor signal. This dynamic control allows the circuit complexity to be adjusted in real-time, maintaining simplicity when equalization is not needed while providing enhanced signal quality when channel losses require it.
3Reliability
If conventional equalizers are used to reduce errors in received data, then signal quality is improved, but area occupied in IC device increases
Solution Approach 1:
The equalizer is divided into multiple segments that can be selectively activated. This segmentation allows the circuit area to be optimized by only instantiating and activating the necessary equalizer segments, reducing the total area occupied in the IC device while maintaining signal quality through targeted equalization.
4Reliability
If deemphasis is applied to all driver segments, then channel losses are reduced, but power consumption increases
Solution Approach 1:
Deemphasis is applied locally to only those driver segments that require it, based on the state of the precursor signal. This selective local equalization reduces channel losses in specific segments while avoiding unnecessary power consumption in segments that do not require equalization, optimizing the balance between signal quality and power usage.
Data Source
AI summary
An equalizing transmitter coupled to a communication channel includes a plurality of driver segments, at least one equalizer segment, a delay element and a logic circuit. Each driver segment in the plurality of driver segments includes a pullup transistor that is configured to couple the communication channel to a first voltage rail when an input signal is in a first signaling state. The at least one equalizer segment includes a pullup transistor configured to couple the communication channel to the first voltage rail when turned on. The delay element is configured to provide a precursor signal that is a delayed version of the input signal. The logic circuit is responsive to the precursor signal and provides an enabling signal that enables the at least one equalizer segment to be turned on when the precursor signal is in a second signaling state.