Gamma Amplifier Sample-Hold Offset Cancellation With Lower Power

Solution Overview

Problem

Existing gamma amplifiers in display driver integrated circuits face inefficiencies in auto-zero operations due to process issues, leading to reduced stability and increased power consumption.

Innovation Solution

A gamma amplifier design with alternating sample and hold periods, incorporating a first gamma amplification stage, a sample driving stage, and a hold driving stage, where the sample driving stage consumes less power than the hold driving stage, and a switching stage to connect these stages based on operation periods, allowing for efficient offset cancellation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a gamma amplifier performs auto-zero operation to cancel offsets, then manufacturing precision is improved, but power consumption increases

Engineering Contradiction:

Improveoffset cancellationVSAvoidpower consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The gamma amplifier performs auto-zero operation periodically at specific moments (e.g., during display refresh intervals or when displaying uniform content) rather than continuously. The controller activates the auto-zero function only during designated sample periods, allowing offset cancellation to occur intermittently while maintaining display operation, thereby reducing overall power consumption while still achieving effective offset compensation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the auto-zero operation based on display content and timing conditions. The controller monitors display refresh cycles and content characteristics to determine optimal moments for auto-zero execution, adapting the operation to actual display needs rather than running at fixed intervals, thus balancing precision requirements with power efficiency.

Inventive Principle:

Principle #15Dynamics

2Stability of the object's composition

If a gamma amplifier performs continuous auto-zero operation, then stability is improved, but power consumption increases

Engineering Contradiction:

Improveauto-zero operation stabilityVSAvoidpower consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The gamma amplifier performs auto-zero operation periodically at specific moments (e.g., during display refresh intervals or when displaying uniform content) rather than continuously. The controller activates the auto-zero function only during designated sample periods, allowing offset cancellation to occur intermittently while maintaining display operation, thereby reducing overall power consumption while still achieving effective offset compensation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system performs auto-zero operation in advance during idle periods or display refresh intervals before actual display content is rendered. By pre-correcting offsets during these preparatory periods, the amplifier ensures stable operation during subsequent display cycles without requiring continuous correction, thus maintaining stability while reducing power consumption during active display periods.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Use of energy by moving object

If the sample driving stage consumes less power, then power efficiency is improved, but the hold driving stage requires higher power for stable operation

Engineering Contradiction:

Improvesample driving stage power consumptionVSAvoidhold driving stage power consumption

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The gamma amplifier performs auto-zero operation periodically at specific moments (e.g., during display refresh intervals or when displaying uniform content) rather than continuously. The controller activates the auto-zero function only during designated sample periods, allowing offset cancellation to occur intermittently while maintaining display operation, thereby reducing overall power consumption while still achieving effective offset compensation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The driving stage is segmented into sample driving and hold driving sub-stages with distinct power consumption characteristics. The sample driving stage operates at lower power during offset sampling, while the hold driving stage maintains higher power only when needed for stable voltage holding during display periods. This segmentation allows each sub-stage to be optimized for its specific function, improving overall power efficiency.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250342789A1Gamma amplifier operating in sample period and hold period for offset cancellation, gamma voltage generator including the same, and display driver integrated circuit including the same

Publication Date: 2025.11.06 SAMSUNG ELECTRONICS CO LTD

AI summary

A gamma amplifier includes a first gamma amplification stage that amplifies a first voltage, a sample driving stage that amplifies a second voltage that is output from the first gamma amplification stage, during a first sample period in which a first offset of the gamma amplifier is sampled, a hold driving stage that amplifies a third voltage that is output from the first gamma amplification stage, during a first hold period in which the first offset is canceled, and a switching stage that connects the first gamma amplification stage to one stage of the hold driving stage and the sample driving stage. The sample driving stage consumes less power than the hold driving stage.