Source Driver Sensing Circuit Without Feedback Capacitors

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Solution Overview

Problem

Conventional source drivers require feedback capacitors for each channel, leading to performance variations based on panel load and increased chip area, necessitating a solution to reduce these dependencies and minimize chip area.

Innovation Solution

Incorporating an amplifier circuit that converts input current into an output current with reduced amplitude, eliminating the need for feedback capacitors and utilizing a smaller sampling capacitor, thereby reducing chip area and maintaining performance across multiple channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If feedback capacitors are used for each channel in the integrator, then the integrator performance is maintained under varying panel loads, but the chip area increases due to multiple capacitors

Engineering Contradiction:

Improveintegrator performanceVSAvoidchip area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the feedback capacitor function into a shared resource across multiple channels rather than having dedicated feedback capacitors for each channel. The integrator circuit uses a common feedback capacitor that serves multiple sensing circuits, thereby reducing the total chip area while maintaining integrator performance through careful circuit design that ensures proper feedback action across all channels.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The feedback capacitor is designed to serve multiple functions and multiple channels simultaneously. A single feedback capacitor structure provides feedback action for multiple sensing circuits across different channels, making the capacitor a universal component that reduces overall component count and chip area while maintaining the necessary integrator functionality for all channels.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If a larger sampling capacitor is used to accurately sample pixel signals, then sensing accuracy is improved, but the chip area increases

Engineering Contradiction:

Improvepixel signal sensing accuracyVSAvoidchip area

Core Design Contradiction:

Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent employs parameter changes in the amplifier circuit to enable the use of a smaller sampling capacitor. By optimizing the amplifier gain and adjusting circuit parameters such as transistor sizing and biasing conditions, the circuit achieves accurate pixel signal sensing with reduced capacitance values, thereby maintaining measurement precision while minimizing chip area.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses current mirror circuits to copy and amplify the pixel signal current before sampling. By creating accurate current copies through mirror transistors and amplifying the signal current, the circuit achieves sufficient signal level for accurate sampling with a smaller sampling capacitor, thus reducing chip area while maintaining sensing accuracy.

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If the number of channels is increased to cover more pixel signals, then the coverage is improved, but the chip area increases due to more feedback capacitors

Engineering Contradiction:

Improvechannel coverageVSAvoidchip area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent designs the feedback capacitor structure to serve multiple channels universally. A single feedback capacitor or a small number of shared feedback capacitors provide feedback action for multiple sensing circuits across different channels, enabling the source driver to handle increased channel coverage without proportionally increasing chip area with dedicated capacitors for each channel.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the feedback capacitor resources across multiple channels, combining what would otherwise be separate components into shared resources. Multiple sensing circuits share common feedback capacitor structures, thereby enabling increased channel coverage while minimizing the total chip area required for feedback components.

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration decreases the impact of panel load on integrator performance, reduces chip area by eliminating feedback capacitors, and allows for accurate pixel signal sensing across multiple channels with a smaller sampling capacitor, enhancing efficiency and compactness.

Implementation Method 1

an amplifier circuit configured to receive an input current from a display panel, wherein the amplifier circuit converts the input current into an output current

Methodology Applied

Scientific EffectCurrent amplification:

Implementation Method 2

a sampling circuit configured to output the sampling voltage by sampling the output current

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11657766B2Sensing circuit and source driver including the same

Publication Date: 2023.05.23 LX SEMICON CO LTD

AI summary

The present disclosure discloses a sensing circuit and a source driver including the same, capable of decreasing influence on the performance of an integrator according to a panel load and reducing a chip area by excluding a feedback capacitor of the integrator. The sensing circuit may convert an input current, received from a display panel, into an output current having linearity and an amount of current smaller than the input current.