Ramp Signal Slope Correction for Linear Analog Gain

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Solution Overview

Problem

Existing electronic devices face challenges in maintaining the linearity of analog gain when the slope of a ramp signal is adjusted, leading to operational reliability issues due to process variations in resistor values.

Innovation Solution

The implementation of a ramp signal generation circuit and slope correction circuit that adjust and correct the slope of a ramp signal using variable resistances and correction codes, ensuring the analog gain remains constant by adjusting the slope in multiple levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the slope of the ramp signal is adjusted to change analog gain, then the analog gain can be adapted to different illumination conditions, but the linearity of the analog gain deteriorates due to process variations in resistor values

Engineering Contradiction:

Improveanalog gain adaptationVSAvoidlinearity of analog gain

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The slope correction is divided into multiple discrete levels (first level, second level, etc.) that can be selectively applied. Each correction level corresponds to specific process variation conditions, allowing the system to segment the correction process into manageable steps that maintain linearity across different operating conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the slope parameter of the ramp signal by applying correction levels that adjust the slope by specific amounts (first level, second level). This parameter change approach allows the system to compensate for process variations by modifying the slope parameter dynamically while maintaining the intended analog gain linearity.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If multiple correction levels are applied to maintain linearity, then the manufacturing precision of analog gain is improved, but the device complexity increases

Engineering Contradiction:

Improvelinearity of analog gainVSAvoidcircuit structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The slope correction circuit is designed to dynamically select and apply appropriate correction levels based on process variation conditions. The circuit can adaptively adjust the slope by different levels (first level, second level) depending on the specific analog gain setting and detected variations, making the correction process dynamic rather than static.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Different correction levels are applied locally to specific slope conditions. The first slope correction applies a first correction level for certain conditions, while the second slope correction applies a second correction level for other conditions. This local quality approach ensures that each part of the correction process is optimized for its specific operating range.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10848136B2Electronic device

Publication Date: 2020.11.24 SK HYNIX INC

AI summary

Provided is an electronic device including a ramp signal generation circuit configured to generate a ramp signal having a second slope that is greater by a first level than a first slope which corresponds to an analog gain, and a slope correction circuit configured to correct the second slope of the ramp signal by the first level to obtain the first slope.