LED Module Current Calibration via PWM Duty Cycle Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing calibration methods for LED modules in projection devices require external apparatuses to detect and adjust driving current, leading to increased equipment costs and unstable accuracy, limiting the precision of the calibration process.
Innovation Solution
A projection device with a driver, LED module, current sensor, and controller that generates a control signal to adjust the driving current within a target range without altering the resistance value of the current limiting resistor, allowing for high-precision calibration of the LED module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external apparatuses are used to detect and adjust driving current, then calibration can be performed, but equipment cost increases and accuracy stability deteriorates
Solution Approach 1:
The projection device performs self-calibration by using its own controller to detect the driving current through a current sensor and adjust the driving current accordingly, eliminating the need for external calibration apparatuses. The controller reads the actual driving current value, compares it with the target value, and adjusts the PWM duty cycle to achieve accurate calibration independently.
Solution Approach 2:
The patent replaces the mechanical adjustment of current limiting resistor resistance values with an electronic control method using PWM duty cycle adjustment. This substitution eliminates the need for physical resistor changes and external measurement devices, reducing equipment cost while maintaining calibration accuracy through digital control.
2Measurement precision
If resistance value of current limiting resistor is adjusted, then driving current can be calibrated, but accuracy stability deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of the driving current through PWM duty cycle control, allowing the system to adaptively correct current deviations in real-time. Unlike static resistor adjustments, the controller can continuously monitor and adjust the driving current to maintain stable accuracy throughout the LED module's operation.
Solution Approach 2:
The patent changes the control parameter from resistance value (which has inherent tolerance and stability issues) to PWM duty cycle (which can be precisely controlled digitally). By adjusting the duty cycle parameter, the system achieves more stable and repeatable current calibration without the accuracy limitations of physical resistors.
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 high-precision calibration of the LED module without external apparatuses, reducing calibration costs and eliminating accuracy limitations associated with current limiting resistors, while maintaining the LED module's output within a target brightness range.
Implementation Method 1
The current sensor senses a driving current flowing through the LED module to generate a sensing signal
Implementation Method 2
The LED module provides an output light beam in a target brightness value range in response to the driving current signal
Data Source
AI summary
A projection device and an operation method of the projection device are provided. The projection device includes a driver, a LED module, a current sensor, and a controller. The driver generates a driving current signal according to a control signal. The LED module provides an output light beam in response to the driving current signal. The current sensor senses a driving current flowing through the LED module to generate a sensing signal. The controller generates the control signal according to a current calibration parameter and a first control parameter, and determines whether a current value of the driving current flowing through the LED module is in a target driving current value range. When the current value of the driving current is not in the target drive current value range, the controller changes the first control parameter to adjust the control signal.