MIPI Analog Switch Using Clock Voltage for Multi-Source Selection

Solution Overview

Problem

Existing MIPI interface systems require an additional GPIO interface to switch between multiple data sources, which complicates the processor's control and increases signal lines, limiting efficiency in mobile devices.

Innovation Solution

The solution eliminates the need for an external GPIO interface by using clock signals to select between MIPI sources, leveraging the voltage swing in the STOP state to determine which source to connect, employing logic gates or comparators to monitor and decode these signals for selection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an external GPIO interface is used to select between multiple MIPI sources, then source selection capability is achieved, but device complexity and signal line count increase

Engineering Contradiction:

Improvesource selection capabilityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the source selection function with the existing clock lane by detecting voltage swing characteristics of clock signals from different sources. Instead of using a separate GPIO interface for selection, the system combines source identification with the clock signal path, allowing the clock lane to carry both timing information and source identification data through its voltage characteristics.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The clock lane is given multi-functionality by enabling it to perform both its traditional timing function and source identification function. The clock signal's voltage swing characteristics are utilized to encode source information, allowing the same physical interface to serve multiple purposes: providing clock timing and simultaneously indicating which data source is active.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If an external GPIO interface is used to select between multiple MIPI sources, then source selection capability is achieved, but the number of signal lines increases

Engineering Contradiction:

Improvesource selection capabilityVSAvoidsignal line count

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges the source selection function with the existing clock lane by detecting voltage swing characteristics of clock signals from different sources. Instead of using a separate GPIO interface for selection, the system combines source identification with the clock signal path, allowing the clock lane to carry both timing information and source identification data through its voltage characteristics.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The clock lane is given multi-functionality by enabling it to perform both its traditional timing function and source identification function. The clock signal's voltage swing characteristics are utilized to encode source information, allowing the same physical interface to serve multiple purposes: providing clock timing and simultaneously indicating which data source is active.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If clock signals are used to control source selection, then GPIO interface is eliminated, but detection complexity increases

Engineering Contradiction:

Improvedevice complexityVSAvoiddetection complexity

Core Design Contradiction:

Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent utilizes changes in voltage swing parameters of the clock signal to encode source identification information. Different data sources produce clock signals with distinct voltage swing characteristics, and the detection circuit measures these parameter variations to determine which source is active, converting a potentially complex selection problem into a parameter comparison task.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/electrical GPIO-based selection mechanism with an electrical parameter-based detection system. Instead of using discrete control signals to select sources, the system uses continuous monitoring of clock signal voltage characteristics to automatically identify and route from the active source, substituting a control-oriented approach with a sensing-oriented approach.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8207759B2MIPI analog switch for automatic selection of multiple inputs based on clock voltages

Publication Date: 2012.06.26 SEMICON COMPONENTS IND LLC

AI summary

An MIPI interface is connected to two sensor sources that each may be transferring both high and low speed information, typically video information in the high speed state. The clock signals are monitored and when one of the clock signals exceed a threshold, an analog switch between the MIPI interface and the sensors, may connect the other source to the MIPI interface.