LED Control Circuit with Temperature Compensation
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Solution Overview
Problem
Conventional LED backlight systems require a microprocessor for precise control of luminance and color, leading to increased production costs due to temperature-induced variations in LED properties.
Innovation Solution
A circuit with a waveform generator for PWM control, a temperature detector using linearly variable resistance, and a PWM controller to generate a PWM voltage with a duty cycle based on temperature detection, eliminating the need for a microprocessor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microprocessor is used for precise control of LED luminance and color, then control precision is improved, but device complexity and production cost increase
Solution Approach 1:
The patent extracts the microprocessor from the system and replaces it with dedicated control circuits (PWM controller, temperature detector, waveform generator) that perform specific functions. This removes the complex processing unit while maintaining control precision through specialized hardware components designed for their specific tasks.
Solution Approach 2:
The patent replaces the software-based microprocessor control system with a hardware-based circuit control system. The PWM controller, temperature detector, and waveform generator work together as an integrated hardware solution, substituting the mechanical/electronic processing system with a dedicated control circuit architecture that achieves the same control objectives without requiring a microprocessor.
2Manufacturing precision
If a microprocessor is used for temperature compensation, then luminance and color uniformity are improved, but production cost increases
Solution Approach 1:
The patent extracts the temperature compensation function from the microprocessor and implements it through dedicated control circuits. The temperature detector monitors temperature changes, and the PWM controller adjusts LED driving parameters accordingly, achieving luminance and color uniformity without the need for expensive microprocessor-based compensation algorithms.
Solution Approach 2:
The patent uses simpler, more cost-effective control circuits instead of expensive microprocessors. The dedicated PWM controller and temperature detector provide sufficient temperature compensation functionality at a lower cost, sacrificing the versatility and programmability of a microprocessor for the specific purpose of achieving uniform LED performance.
3Device complexity
If conventional control methods are used, then device simplicity is maintained, but temperature-induced variations in LED properties cannot be compensated
Solution Approach 1:
The patent segments the control function into separate dedicated components: a waveform generator for PWM signals, a temperature detector for monitoring, and a PWM controller for adjustment. This segmentation allows each component to perform its specific function effectively, achieving temperature compensation without requiring a complex integrated microprocessor system.
Solution Approach 2:
The patent introduces a temperature detector as an intermediary between the environment and the PWM controller. The detector monitors temperature changes and provides feedback to the PWM controller, which then adjusts LED driving parameters accordingly. This intermediary mechanism enables temperature compensation through a simple feedback loop without requiring complex microprocessor intervention.
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
Enables precise linear control of luminance and color in LED systems, effectively compensating for temperature variations without a microprocessor, thereby reducing costs and ensuring uniformity across different LED characteristics.
Implementation Method 1
a temperature detector for detecting a voltage through a resistance value which is linearly variable according to changes in an ambient temperature
Implementation Method 2
a waveform generator for generating a sawtooth wave for Pulse Width Modulation (PWM) control
Implementation Method 3
a PWM controller for comparing the sawtooth wave from the wave generator with the detection voltage from the temperature detector and generating a PWM voltage having a duty determined by the comparison result
Data Source
AI summary
A circuit for controlling an LED with temperature compensation is employed in the LED-based system. The circuit of the invention linearly controls luminance and color of the LED according to temperature change and more precisely compensates for temperature-related variations in LED properties. Also, the circuit saves the cost of the product due to no requirement of a microprocessor. In the circuit, a waveform generator generates a sawtooth wave for Pulse Width Modulation (PWM) control. A temperature detector detects a voltage via a resistance value which is linearly variable according to changes in an ambient temperature. A PWM controller compares the sawtooth wave from the wave generator with the detection voltage from the temperature detector and generates a PWM voltage having a duty determined by the comparison result.