Differential I/O Buffer Encoding for Power and Noise Reduction
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Solution Overview
Problem
Differential input/output (I/O) buffers face challenges in reducing power consumption and noise, as power consumption and noise vary with data transmission, and existing techniques like Data Bus Inversion (DBI) do not effectively minimize power consumption across all data transitions.
Innovation Solution
Implementing a power-aware scheme that determines and applies selective encoding schemes, such as bit inversions or transition swapping, based on the number of transitions at each clock edge to minimize power consumption and noise, using logic to generate and transmit a 'Scode' for encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Data Bus Inversion (DBI) is used for power reduction, then power consumption is reduced, but noise reduction is not effective and power consumption varies with data transmitted
Solution Approach 1:
The patent applies inversion by transmitting the complement of the actual data value. When the actual data is logic 0, the transmitted signal is logic 1, and vice versa. This inversion technique, combined with differential signaling, balances the switching activity between complementary signal pairs, thereby reducing both power consumption and power supply noise simultaneously.
Solution Approach 2:
The patent changes the parameter of signal encoding from direct data transmission to inverted data transmission. By modifying the logical state (0 or 1) of the transmitted signal based on the actual data value, the system achieves more uniform power consumption characteristics and reduced noise across different data patterns.
2Use of energy by moving object
If selective encoding schemes are applied based on data transitions, then power consumption is minimized, but device complexity increases
Solution Approach 1:
The patent applies local quality by selectively applying different encoding schemes to different groups of differential signal pairs based on their specific transition characteristics. Each group can use the most appropriate encoding scheme (no encoding, bit inversion, or swap encoding) tailored to its local power consumption needs, rather than applying a uniform encoding scheme across all signals.
Solution Approach 2:
The patent implements dynamic encoding scheme selection where the encoding approach changes based on the data pattern and transition activity. The system dynamically determines which encoding scheme to apply by analyzing the actual data values and transition counts, allowing flexible adaptation to different operating conditions while maintaining relatively simple circuit implementation.
Data Source
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AI summary
An apparatus, system, and method for improved power consumption and/or noise reduction in a differential input/output (I/O) buffer are provided. A circuit can include a differential signal buffer and encoding scheme quantifying and selection circuitry. The encoding scheme quantifying and selection circuitry can be configured to generate a selection code indicating a selected encoding scheme of the encoding schemes based on respective signals indicating whether each respective encoding scheme of encoding schemes has a net positive power consumption reduction in differential signals. The encoding scheme quantifying and selection circuitry can be configured to provide the selection code to an encoder.