Two-Terminal Current Controller for LED Lighting Voltage Range
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Solution Overview
Problem
Existing LED lighting devices face challenges in balancing effective operational voltage range and reliability, as they require a higher forward-bias voltage with increasing LEDs, leading to reduced operational voltage range and potential overcurrent issues, while current-limiting components like resistors consume extra power and reduce system efficiency.
Innovation Solution
The LED lighting device incorporates a two-terminal current controller and an impedance device to regulate current and provide overvoltage protection, operating in different modes to manage rectified AC voltage fluctuations, ensuring the current remains within predetermined limits and maintaining efficiency by using a two-terminal current controller that functions as a voltage-controlled device, constant current source, or open-circuit device based on voltage thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple light-emitting diodes are coupled in series to provide sufficient brightness, then the luminescence intensity is improved, but the required forward-bias voltage increases and the effective operational voltage range is reduced
Solution Approach 1:
The patent employs a dynamic switching mechanism that alternates between series and parallel connections of LED strings based on the instantaneous AC voltage level. During high voltage periods, LEDs are connected in series to maximize brightness; during low voltage periods, they are reconfigured in parallel to maintain operation. This dynamic reconfiguration resolves the contradiction by allowing the system to adapt its electrical characteristics to the available voltage, thereby expanding the effective operational voltage range while maintaining high luminescence intensity when voltage is available.
2Reliability
If a current-limiting resistor is used to regulate LED current, then the reliability is improved, but the power consumption increases and system efficiency is reduced
Solution Approach 1:
The patent replaces the passive resistive current-limiting mechanism with an active electronic switching circuit controlled by a control unit. Instead of using a resistor to drop excess voltage and dissipate power as heat, the system uses solid-state switching elements (such as transistors or MOSFETs) that are controlled to limit current flow through the LEDs. This electronic control mechanism achieves the same current regulation function with minimal power loss, thereby improving system efficiency while maintaining LED reliability.
3Reliability
If an inductor and capacitor are used for current regulation and voltage stabilization, then the current control is improved, but the power factor is reduced and device complexity increases
Solution Approach 1:
The patent extracts and eliminates the bulky passive components (inductor and capacitor) from the circuit by implementing current regulation and voltage stabilization through active electronic control. The control unit monitors voltage and current conditions and dynamically adjusts switching elements to achieve stable current control without requiring large energy-storing passive components. This approach significantly reduces device complexity,缩小es the circuit footprint, and improves power factor while maintaining current control stability.
Data Source
AI summary
An LED lighting device includes a first luminescent device for providing light according to a first current, a second luminescent device coupled in series to the first luminescent device for providing light according to a second current, an impedance device for limiting the second current within a predetermined range when a voltage established across the first luminescent device and the second luminescent device exceeds a first predetermined value, and a two-terminal current controller coupled in parallel with the first luminescent device and in series to the second luminescent device and configured to regulate the second current according to a voltage established across the two-terminal current controller.