Adaptive Driver Buffer Control for Low-EMI MIPI Timing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

MIPI data-processing circuits face challenges in dynamically adjusting driver strength to accommodate variations in device characteristics and load capacitance, leading to suboptimal operation and increased Electromagnetic Interference (EMI) due to fixed driver-strength settings.

Innovation Solution

A data-processing circuit with an adjustable-driver-buffer and a driver-control-module that processes clock and data signals to determine a timing-delay-signal, allowing for adaptive driver-strength adjustment based on a target-delay-signal, thereby minimizing the difference between the two, and reducing EMI by varying the current level of the data-output-signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed driver-strength setting is used, then the device complexity is reduced, but the Electromagnetic Interference (EMI) increases and optimal operation cannot be maintained under varying conditions

Engineering Contradiction:
Improvedriver-strength adjustment mechanismVSAvoidElectromagnetic Interference (EMI)
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The driver strength is made dynamically adjustable through a feedback control mechanism. The system continuously monitors the actual delay between clock and data signals and automatically adjusts the driver strength to optimize performance. This dynamic adjustment resolves the contradiction by allowing the system to adapt to varying conditions without requiring complex manual configuration, thereby reducing EMI while maintaining operational simplicity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A feedback control loop is implemented that measures the actual signal delay and uses this information to adjust the driver strength. The feedback mechanism compares the measured delay against a target delay and modifies the driver strength accordingly. This feedback approach enables the system to automatically minimize EMI while maintaining optimal timing, resolving the contradiction between simplicity and performance.

Inventive Principle:
Principle #23Feedback

2Reliability

If the driver-strength is increased to accommodate variations in load capacitance and device characteristics, then the signal integrity is improved, but the Electromagnetic Interference (EMI) increases

Engineering Contradiction:
Improvesignal integrityVSAvoidElectromagnetic Interference (EMI)
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically changes the driver strength parameter based on measured timing conditions. By adjusting the driver strength to match the actual signal delay characteristics, the system maintains optimal signal integrity without applying excessive drive strength that would generate unnecessary EMI. This parameter adaptation resolves the contradiction by optimizing the driver strength for each operating condition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The driver strength transitions from a fixed parameter to a dynamically adjustable one. The system continuously adapts the driver strength to match the actual timing requirements, ensuring signal integrity is maintained only when necessary. This dynamic approach prevents excessive EMI generation while preserving signal quality under varying load and device conditions.

Inventive Principle:
Principle #15Dynamics

3Object-generated harmful factors

If the driver-strength is decreased to reduce EMI, then the Electromagnetic Interference (EMI) is reduced, but the ability to accommodate variations in load capacitance and device characteristics deteriorates

Engineering Contradiction:
ImproveElectromagnetic Interference (EMI)VSAvoidaccommodation of variations in load capacitance and device characteristics
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The feedback mechanism continuously monitors timing delays and adjusts the driver strength to maintain optimal performance. This feedback control ensures that the driver strength is increased only when necessary to accommodate variations in load capacitance and device characteristics, rather than being permanently set to a high value. This resolves the contradiction by minimizing EMI while preserving adaptability through intelligent adjustment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The driver strength is made dynamically adjustable to match actual operating conditions. The system transitions from a static, conservative driver strength setting to a dynamic one that adapts to varying load capacitance and device characteristics. This dynamic approach maintains adaptability while minimizing EMI by using the minimum necessary driver strength for each condition.

Inventive Principle:
Principle #15Dynamics

4Ease of operation

If a fixed driver-strength setting is used, then the ease of operation is improved, but the productivity deteriorates due to suboptimal operation under varying conditions

Engineering Contradiction:
Improvedriver-strength configurationVSAvoidcommunication efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The system performs self-adjustment of the driver strength without requiring external intervention or complex configuration. The automatic feedback control mechanism monitors timing conditions and adjusts the driver strength autonomously, maintaining ease of operation while optimizing communication efficiency. This self-service approach resolves the contradiction by eliminating the need for manual tuning while maximizing productivity under varying conditions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The driver strength transitions from a manually configured fixed parameter to a dynamically self-adjusting parameter. The system automatically adapts the driver strength to optimize communication efficiency without requiring user intervention. This dynamic self-adjustment maintains ease of operation while significantly improving productivity by ensuring optimal performance under all operating conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3386107B1Data processing circuits
Publication Date: 2021.07.07 NXP BV
  • EP3386107B1 patent drawingFigure 1~2
  • EP3386107B1 patent drawingFigure 3
  • EP3386107B1 patent drawing

AI summary

A data-processing-circuit comprising: a clock-input-terminal configured to receive a clock-signal; a data-output-terminal configured to provide a data-output-signal; an adjustable-driver-buffer configured to: receive a data-signal; and apply a driver-strength-value to the data-signal in order to provide a data-output-signal, wherein the current level of the data-output-signal is based on the driver-strength-value; and a driver-control-module comprising: a time-alignment-module configured to: process the clock-signal and the data-output-signal in order to determine a timing-delay-signal that is representative of a time delay between: (i) a transition in the clock-signal; and (ii) a transition in the data-output-signal; provide the driver-strength-value for the adjustable-driver-buffer based on the timing-delay-signal and a target-delay-signal, wherein the driver-strength-value is for reducing a difference between: (i) the timing-delay-signal; and (ii) the target-delay-signal.