OR-Chained Bus Encoding for Parked-State Power Reduction
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Solution Overview
Problem
Existing data bus encoding schemes, such as DBI and WC, increase switching activity and power consumption when combining buses, especially when a 'parked' state is used, as they do not consider the transition from a valid to a parked state, leading to higher power consumption and delays.
Innovation Solution
The Enhanced Data Bus Invert (EDBI) encoding technique determines whether the next data value will transition to a parked state and uses both Hamming Distance and weight calculations to minimize bit transitions, reducing switching activity and power consumption by encoding data based on this determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Data Bus Invert (DBI) encoding is used to transmit data, then data transmission capability is improved, but switching activity and power consumption increase when combining buses with parked state transitions
Solution Approach 1:
The EDBI encoder performs preliminary analysis of the next data value and determines in advance whether it will transition to a parked state. By calculating the Hamming distance and weight of the next data value before transmission, the encoder can proactively select the optimal encoding path (DBI or non-DBI) to minimize switching activity, rather than reactively responding to transitions after they occur.
Solution Approach 2:
The EDBI encoding scheme dynamically adapts its encoding strategy based on the characteristics of the next data value. The encoder switches between DBI and non-DBI encoding modes in real-time, selecting DBI only when the next data value indicates a transition to parked state, and using non-DBI encoding otherwise. This dynamic adaptation minimizes unnecessary switching activity and reduces power consumption while maintaining data transmission capability.
2Productivity
If Data Bus Invert (DBI) encoding is used to transmit data, then data transmission capability is improved, but transmission delays increase when combining buses with parked state transitions
Solution Approach 1:
The EDBI encoder performs preliminary analysis of the next data value and determines in advance whether it will transition to a parked state. By calculating the Hamming distance and weight of the next data value before transmission, the encoder can proactively select the optimal encoding path (DBI or non-DBI) to minimize switching activity, rather than reactively responding to transitions after they occur.
Solution Approach 2:
The EDBI encoding scheme dynamically adapts its encoding strategy based on the characteristics of the next data value. The encoder switches between DBI and non-DBI encoding modes in real-time, selecting DBI only when the next data value indicates a transition to parked state, and using non-DBI encoding otherwise. This dynamic adaptation minimizes unnecessary switching activity and reduces power consumption while maintaining data transmission capability.
3Device complexity
If buses are combined using OR chaining with parked state, then device complexity is reduced, but switching activity increases leading to higher power consumption
Solution Approach 1:
The EDBI encoder applies different encoding qualities to different data transmission scenarios. When the next data value indicates a transition to parked state, the encoder applies DBI encoding with inverted bits to minimize switching. For other cases, it uses standard non-DBI encoding. This localized application of encoding strategies optimizes power consumption specifically at the points where parked state transitions occur, without adding complexity to the overall bus combination architecture.
Data Source
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Figure 3A~3B
AI summary
Methods and apparatus relating to enhanced Data Bus Invert (EDBI) encoding for OR chained buses are described. In an embodiment, incoming data on a bus is encoded based at least in part on a determination of whether a next data value on the bus is going to transitioning from a valid value to a parked state. Other embodiments are also disclosed.