LED Lighting Apparatus Flicker Reduction via Capacitor Charge Discharge
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Solution Overview
Problem
Lighting apparatuses using LEDs can experience flicker due to the characteristics of rectified voltage, which is not effectively addressed by existing technologies, leading to inconsistent light emission and power factor issues.
Innovation Solution
A lighting apparatus that includes a flicker control circuit and capacitors to perform charge and discharge operations with rectified voltage, dividing LEDs into groups and using a control unit to manage current paths and light emission, thereby reducing flicker and improving power factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a rectified voltage is used to drive LEDs directly without additional circuits, then the power factor is improved and device complexity is reduced, but flicker occurs due to the periodic turn-off characteristic of the rectified voltage
Solution Approach 1:
The capacitor is charged in advance during the period when rectified voltage is above the threshold level, storing energy before the voltage drops. This preliminary energy storage ensures continuous LED operation during the voltage low period, preventing flicker while maintaining the simple circuit structure.
Solution Approach 2:
A capacitor is introduced as an intermediary energy storage element between the rectified voltage source and the LEDs. The capacitor mediates the power delivery by storing energy when voltage is high and releasing it when voltage is low, smoothing out the periodic interruptions that cause flicker without requiring complex circuitry.
2Object-affected harmful factors
If the capacitor capacity is increased to reduce flicker, then flicker is reduced, but the device complexity and component count increase
Solution Approach 1:
The patent determines an optimal capacitor capacity range based on the relationship between capacitor capacity, rectified voltage characteristics, and LED operating parameters. By optimizing this parameter, the patent achieves effective flicker reduction with a capacitor that is not excessively large, balancing performance with device complexity and component size.
3Illumination intensity
If LEDs are operated at high current to increase light intensity, then light emission is improved, but power factor deteriorates and energy efficiency decreases
Solution Approach 1:
The system operates in periodic cycles: during the first period when rectified voltage is above threshold, the capacitor charges and LEDs operate at normal current for efficient light emission. During the second period when voltage drops below threshold, the capacitor discharges to maintain LED operation. This periodic operation allows LEDs to run at optimal current levels throughout both periods, maintaining light intensity while preserving power factor through the capacitor's energy buffering作用.
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 solution effectively reduces flicker and maintains constant brightness across varying light intensities, improving power factor by regulating current flow and using a minimal number of components, ensuring efficient LED operation.
Implementation Method 1
a capacitor configured to secure a charge voltage by performing a first charge operation based on a magnitude-limited current using the rectified voltage which is equal to or more than a first level and provided through one or more LEDs, and provide the charge voltage to an input terminal of the lighting unit through a first discharge operation
Data Source
AI summary
Disclosed is a lighting apparatus which includes LEDs and reduces flicker. The lighting apparatus may secure a charge voltage by performing a charge operation using a current corresponding to a rectified voltage equal to or more than a preset level, and compensate for the rectified voltage provided to a lighting unit including LED groups by performing a discharge operation for the charge voltage in response to the rectified voltage less than the preset level, thereby reducing flicker.