LED Driver Non-Linear Compensation Using Bezier Curves
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Solution Overview
Problem
Existing LED driver circuitry struggles with precise non-linear compensation, requiring large look-up tables for accurate compensation, which complicates programming and increases memory usage, and lacks flexibility to implement multiple compensation curves effectively.
Innovation Solution
The use of parametric quadratic Bezier curves, stored with a single control point, allows for efficient non-linear compensation of LED drive signals, enabling precise control and easy re-programming through an I2C interface, reducing memory requirements and enhancing application flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of look-up table points are used to achieve reasonable compensation accuracy, then compensation precision is improved, but programming difficulty increases and memory requirements increase
Solution Approach 1:
The patent transforms the compensation approach from using a large discrete look-up table to using a continuous mathematical function (Bezier curve) defined by a small number of parameters. Instead of storing many discrete compensation values, the system uses control points that define a curve equation, which can then calculate any compensation value continuously. This parameter transformation resolves the contradiction by maintaining high precision while dramatically reducing programming complexity.
Solution Approach 2:
The patent creates a simplified mathematical model (Bezier curve representation) that copies or approximates the complex compensation data. Rather than directly implementing the full look-up table, the system uses a compact mathematical representation that reproduces the compensation effect with far fewer elements, thus reducing programming difficulty while preserving accuracy.
2Measurement precision
If a large number of look-up table points are used to achieve reasonable compensation accuracy, then compensation precision is improved, but memory requirements increase
Solution Approach 1:
The patent changes the representation parameters from numerous discrete look-up table entries to a small set of continuous curve parameters. A Bezier curve can be fully defined by just 3-4 control points, replacing what would otherwise require hundreds or thousands of individual memory locations. This parameter transformation achieves the same or better precision with dramatically reduced memory usage.
3Quantity of substance
If hardcoded look-up tables are used to reduce memory usage, then memory requirements are reduced, but application flexibility decreases
Solution Approach 1:
The patent introduces dynamic adjustability by using programmable control points that define the Bezier curve. Unlike hardcoded tables, the curve parameters can be modified at runtime or during manufacturing to adapt to different LED batches, applications, or compensation requirements. This dynamic parameter adjustment maintains low memory usage while providing high flexibility for different applications.
Solution Approach 2:
The Bezier curve mathematical model serves multiple functions: it can represent different compensation curves by changing control points, it can be programmed via I2C interface, and it can adapt to various LED characteristics. This universal mathematical framework replaces multiple application-specific hardcoded tables, providing both memory efficiency and flexibility across different scenarios.
4Device complexity
If analog solutions are used for non-linear compensation, then circuit simplicity is improved, but programmability and support for multiple curve shapes is lost
Solution Approach 1:
The patent replaces the mechanical/analog circuit approach with a digital implementation. Instead of using analog components and circuits to generate non-linear compensation, the system uses digital calculations based on Bezier curve equations. This substitution maintains circuit simplicity at the component level while adding programmability through software-defined curve parameters, resolving the contradiction between simplicity and adaptability.
Data Source
AI summary
A device driver which includes an input driver configured to produce a sequence of uncompensated drive signals along with compensation circuitry connected to receive the uncompensated drive signals and to produce corresponding compensated drive signals. The compensation circuitry is capable of storing two or less control points that define a single compensation curve such as a Bezier curve, with the compensation circuitry converting the uncompensated drive signals to the corresponding compensated drive signals utilizing the control points. An output driver is configured to drive a device such as one or more light emitting diodes to be connected to the output driver with the compensated drive signals.