Interface Circuit Dynamic Impedance Matching for Image Sensors

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Solution Overview

Problem

As the number of semiconductor devices connected to electronic devices increases, insufficient impedance matching between these devices and integrated circuit chips can lead to inaccurate high-speed data communication, particularly when multiple camera modules share a transmission line, resulting in signal deterioration and limited data transmission speed.

Innovation Solution

An interface circuit with a termination resistor block that adjusts the output impedance of transmission circuits based on the operation mode of image sensors, disconnecting or connecting resistors between transfer pads to match impedance, ensuring proper signal transmission by detecting low-power or high-speed data transfer signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple camera modules share a transmission line, then device integration is improved, but impedance matching deteriorates leading to signal deterioration

Engineering Contradiction:

Improvedevice integrationVSAvoidimpedance matching

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic impedance adjustment by switching between different termination resistor configurations based on the operational state of camera modules. The interface circuit changes its impedance characteristics dynamically to match the transmission line impedance, resolving the impedance matching problem that arises when multiple camera modules share a transmission line.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical parameter (impedance) of the interface circuit by selectively connecting or disconnecting termination resistors. This parameter change allows the circuit to adapt to different operational modes, ensuring proper impedance matching whether one or multiple camera modules are actively using the transmission line.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If termination resistors are always connected, then impedance matching is improved, but power consumption increases in low-power modes

Engineering Contradiction:

Improveimpedance matchingVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The termination resistor connection state is made dynamic rather than static. The control circuit monitors the operational mode of the camera module and switches the termination resistor connection accordingly - connected during high-speed data transfer for impedance matching, and disconnected during low-power modes to reduce power consumption.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The termination resistor is periodically connected and disconnected based on the data transfer requirements. During high-speed data transfer periods, the resistor is connected for impedance matching; during low-power periods when no data transfer occurs, the resistor is disconnected to minimize power consumption.

Inventive Principle:

Principle #19Periodic action

3Use of energy by moving object

If termination resistors are disconnected in low-power mode, then power consumption is reduced, but impedance matching deteriorates for high-speed data transfer

Engineering Contradiction:

Improvepower consumptionVSAvoidimpedance matching

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The control circuit prepares the termination resistor connection in advance based on detected operation modes. When high-speed data transfer is detected or anticipated, the termination resistor is connected beforehand to ensure proper impedance matching is established before data transmission begins, preventing signal deterioration.

Inventive Principle:

Principle #10Preliminary action

4Productivity

If impedance matching is optimized for high-speed transfer, then data transmission speed is improved, but power consumption increases

Engineering Contradiction:

Improvedata transmission speedVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts its impedance matching configuration based on the required data transmission speed. For high-speed transfer, termination resistors are connected to optimize impedance matching and maximize transmission speed. For low-speed or idle modes, the resistors are disconnected to reduce power consumption, achieving a dynamic balance between productivity and energy usage.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20230273666A1Interface circuit for controlling output impedance of a transmission circuit and an image sensor including the same

Publication Date: 2023.08.31 SAMSUNG ELECTRONICS CO LTD

AI summary

An interface circuit including: a first transmission circuit outputting a first signal to a transmission line via first transfer pads; and a second transmission circuit outputting a second signal to the transmission line via second transfer pads, the first transmission circuit includes a first termination resistor block including a switch and a first termination resistor connected between the first transfer pads, the second transmission circuit includes a second termination resistor block including a switch and a second termination resistor connected between the second transfer pads, and when the first transmission circuit outputs the first signal, the second termination resistor block detects the first signal, and when the first transmission circuit is in a low-power operation mode, the second termination resistor block disconnects the second termination resistor, and when the first transmission circuit is in a high-speed data transfer mode, the second termination resistor block connects the second termination resistor.