Programmable Gamma Circuit Reducing Area via Segmented DACs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing programmable gamma circuits for displays require large circuit areas and increased production costs due to the high bit width of digital-to-analog converters, particularly in high voltage processes, which complicates the implementation of gamma correction for brightness sensitivity in displays.
Innovation Solution
A programmable gamma circuit design that utilizes a combination of voltage and current paths to reduce the area of the resistor string and equivalent output impedance, allowing for the generation of gamma reference and gamma voltages using a single circuit structure, thereby simplifying the design and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the bit width of digital-to-analog converters is increased to obtain desired gamma characteristic, then the gamma correction precision is improved, but the circuit area increases
Solution Approach 1:
The patent segments the gamma correction function into two separate digital-to-analog converters: one for gamma reference voltage generation and another for gamma voltage generation. This segmentation allows each converter to operate with optimized bit width, reducing the total circuit area while maintaining overall gamma correction precision
Solution Approach 2:
The patent creates a universal gamma correction architecture where the segmented converter structure can be applied to both gamma reference voltage and gamma voltage generation. This multi-functional design eliminates the need for separate high-bit-width converters for each function, reducing overall circuit area while preserving correction precision
2Measurement precision
If the bit width of digital-to-analog converters is increased to obtain desired gamma characteristic, then the gamma correction precision is improved, but the production cost increases
Solution Approach 1:
By segmenting the gamma correction function into separate converters for reference voltage and gamma voltage, the patent reduces the bit width requirement for each individual converter. This segmentation directly lowers manufacturing complexity and production cost while maintaining the overall precision needed for accurate gamma correction
Solution Approach 2:
The patent employs simpler, lower-bit-width digital-to-analog converter designs that are more cost-effective to manufacture. By using multiple simpler converters instead of fewer high-precision converters, the overall production cost is reduced while achieving the same functional precision
3Reliability
If resistor strings of digital-to-analog converters are used in high voltage process, then the gamma correction function is achieved, but the circuit area increases
Solution Approach 1:
The patent segments the resistor string implementation into separate, smaller resistor strings for each digital-to-analog converter. This segmentation reduces the area occupied by resistor strings in high voltage processes while maintaining the reliability of gamma correction function through distributed implementation
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
The proposed solution effectively reduces the circuit area and production costs while enabling efficient gamma correction for displays by using a combined voltage and current path approach, allowing the same circuit structure to be reused for both gamma reference and gamma voltage generation, thus improving brightness correction without increasing complexity.
Implementation Method 1
The string digital-to-analog converter selects an analog voltage from a plurality of candidate voltages according to a digital reference code
Implementation Method 2
An output terminal of the first operational amplifier outputs a first output voltage
Implementation Method 3
The output resistor string is divided into a first resistor part and a second resistor part by a connection terminal, and a resistance of the first resistor part is a multiple of a resistance of the second resistor part
Data Source
AI summary
A programmable gamma circuit for gamma correction is disclosed. The programmable gamma circuit includes a string digital-to-analog converter, a first operational amplifier, and an output resistor string. The string digital-to-analog converter selects an analog voltage from a plurality of candidate voltages according to a digital reference code. An output terminal of the first operational amplifier outputs a first output voltage. A positive input terminal of the first operational amplifier is electrically connected to the string digital-to-analog converter for receiving the analog voltage. The output resistor string is divided into a first resistor part and a second resistor part by a connection terminal which is electrically connected to a negative input terminal of the first operational amplifier, and a resistance of the first resistor part is a multiple of a resistance of the second resistor part.