Accessory Communication Switching to Prevent CS Signal Leakage

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Solution Overview

Problem

Existing systems for connecting accessories to image pickup apparatuses suffer from current leakage due to fixed CS signal logic settings, which restrict the types of accessories that can be used and lead to inefficiencies in communication protocols.

Innovation Solution

Implementing a flexible CS signal logic that allows for both low-active and high-active settings, along with dual communication protocols (SPI and I2C) to ensure compatible communication with a variety of accessories, and incorporating protection circuits to manage current flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the CS signal logic is fixed to low-active, then the communication protocol is simple, but current leakage occurs in the image pickup apparatus

Engineering Contradiction:
Improvecommunication protocol complexityVSAvoidcurrent leakage
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent applies dynamics by making the CS signal logic configurable rather than fixed. The image pickup apparatus can dynamically select between low-active and high-active logic modes based on the attached accessory's requirements. This is implemented through a detection mechanism that identifies the accessory's CS logic type and switches the control circuit accordingly, preventing current leakage while maintaining compatibility with different accessory types.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If the CS signal logic is changed to high-active, then current leakage is prevented, but accessories requiring low-active logic cannot be used

Engineering Contradiction:
Improvecurrent leakage preventionVSAvoidaccessory compatibility
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent implements universality by designing the image pickup apparatus to support both low-active and high-active CS signal logics. The control circuit includes a switching mechanism that can operate in either mode depending on the detected accessory type. This multi-functional design allows the same apparatus to work with diverse accessories without current leakage issues, achieving both energy efficiency and broad compatibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If a fixed CS signal logic is used, then the device structure is simple, but the types of attachable accessories are limited

Engineering Contradiction:
Improvedevice structureVSAvoidaccessory types
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by implementing a detection and switching mechanism that adapts the CS signal logic based on the attached accessory. The control circuit detects whether the accessory requires low-active or high-active logic and switches accordingly. This dynamic adaptation allows the apparatus to support multiple accessory types without significantly increasing structural complexity, as the switching mechanism integrates into the existing communication interface.

Inventive Principle:
Principle #15Dynamics

4Adaptability or versatility

If the CS signal logic is made configurable, then accessory compatibility is improved, but the device complexity increases

Engineering Contradiction:
Improveaccessory compatibilityVSAvoidcontrol circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by implementing an automatic detection and switching mechanism. When an accessory is attached, the control circuit automatically detects the accessory's CS signal logic type (low-active or high-active) and configures itself accordingly without user intervention. This self-configuration approach minimizes the perceived complexity for the user while maintaining the necessary control circuit functionality for broad compatibility.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4080279B1Electronic apparatus, its control method, accessory, its control method, system, and storage medium
Publication Date: 2026.03.18 CANON KK
  • EP4080279B1 patent drawingFigure 1
  • EP4080279B1 patent drawingFigure 2A~2B
  • EP4080279B1 patent drawingFigure 3A~3B

AI summary

An accessory (200) attachable to an electronic apparatus includes an accessory processing unit (201) communicable with an electronic apparatus (100) by a first communication method as communication via a first contact group, and by a second communication method as communication via a second contact group. The accessory processing unit controls the communication by the second communication method based on information communicated by the first communication method, executes communication via a second contact included in the second contact group, in response to a change in a signal level of a signal via a first contact included in the second contact group from a first signal level to a second signal level, and executes communication by the second communication method based on information on the second signal level included in the information communicated by the first communication method.