Constant Total Current Data Communication Encoding

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Solution Overview

Problem

Existing data communication systems require high power consumption and numerous current levels to distinguish symbols, leading to increased power supply bounce and inefficiency, especially when transmitting multi-bit data items.

Innovation Solution

The system encodes symbols using combinations of currents in positive, negative, and zero directions across multiple signal conductors, maintaining a constant total current to reduce power consumption and minimize electromagnetic radiation, with a control circuit managing internal currents to maintain power balance and switch to low-power modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large number of different current levels are used to provide large code capacity, then the number of distinguishable symbols increases, but power supply consumption increases and power bounce increases

Engineering Contradiction:

Improvesymbol distinction capabilityVSAvoidpower supply consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the parameter of current encoding from using multiple current levels to using current direction (positive/negative) and conductor position. This allows distinction of symbols through directional changes rather than magnitude changes, reducing power consumption while maintaining symbol distinction capability.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of varying current magnitude to encode different symbols, the patent inverts the approach by using current direction (positive vs negative) and spatial arrangement of conductors carrying current. This inversion allows symbol encoding without requiring large current magnitudes, thereby reducing power consumption.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If a large number of different current levels are used to provide large code capacity, then the number of distinguishable symbols increases, but the number of comparisons needed to decode symbols increases

Engineering Contradiction:

Improvesymbol distinction capabilityVSAvoiddecoding complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent inverts the decoding approach from comparing current magnitudes to detecting current direction and conductor position. This simplifies the decoding process to basic directional detection rather than multiple magnitude comparisons, reducing decoding complexity while maintaining symbol distinction capability.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the mechanical/electrical comparison system with a field-based detection system. Instead of actively comparing current levels through multiple circuits, the system uses the natural electromagnetic field patterns generated by different conductor configurations, simplifying the detection mechanism.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If differential pairs are used for data transmission, then noise sensitivity is reduced, but the number of conductors required increases

Engineering Contradiction:

Improvenoise sensitivityVSAvoidconductor space

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent merges the functions of multiple differential pairs into a single set of conductors by using spatial arrangement and directional current flow. Instead of requiring separate differential pairs for each signal, the system combines multiple signal functions into one conductor set, reducing space while maintaining noise rejection through balanced current patterns.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent makes the conductor set universal by enabling it to carry multiple signal functions simultaneously through different current direction patterns. The same physical conductors can represent different symbols by varying which conductors carry current in which direction, eliminating the need for dedicated differential pairs for each signal type.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8027405B2Data communication using constant total current

Publication Date: 2011.09.27 NXP BV

AI summary

A data communication system, comprising at least three signal conductors and a first and a second power supply terminal, for supplying currents of mutually opposite direction to the signal conductors respectively. A driver circuit establishes respective combinations of currents through the signal conductors from a selectable set of combinations, which includes combinations with currents from the first supply terminal and to the second supply terminal, so that a sum of the currents through the signal conductors substantially has a same value for each combination and at least one of the conductors in operation does not merely function in a differential-pair relation with another one of the conductors, the driver circuit determining which of the combinations from the set are established depending on information to be transmitted.