AC LED Lamp with Selectively Shortable LED Sections
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Solution Overview
Problem
Existing AC LED lamp circuits face inefficiencies due to power loss from current-limiting resistors, heat generation, and flicker issues, and rely on complex circuitry or electrolytic capacitors that can degrade reliability.
Innovation Solution
An AC LED lamp with a rectifier, integrated circuit, and series-connected LEDs, where power switches selectively short out sections of the LED string to regulate current flow, eliminating electrolytic capacitors and minimizing electromagnetic interference, and employing anti-flicker modes to reduce current during peak voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If current-limiting resistors are used to control LED current, then current regulation is achieved, but power loss and heat generation increase
Solution Approach 1:
The patent replaces the passive mechanical/resistive current-limiting approach with active electronic switching control. Power switches (electronic components) are used to dynamically control current flow through LED sections, substituting the resistive mechanism with a switching mechanism that minimizes power dissipation while maintaining current regulation capability.
Solution Approach 2:
The patent changes the operating parameters by using variable switching states rather than fixed resistance values. The control circuit dynamically adjusts which LED sections are active and which are shorted, changing the electrical parameters (current paths, resistance configurations) in real-time to optimize efficiency while maintaining proper current regulation.
2Stability of the object's composition
If electrolytic capacitors are used for voltage smoothing, then voltage stability is improved, but reliability decreases due to capacitor degradation
Solution Approach 1:
The patent extracts and removes the electrolytic capacitor from the circuit topology. By redesigning the circuit to operate without this component, the reliability issue associated with capacitor degradation is eliminated while voltage stability is maintained through alternative means (controlled rectification and switching).
Solution Approach 2:
The patent eliminates the use of short-living electrolytic capacitors that require replacement. The design uses more reliable solid-state components with longer operational lifetimes, avoiding the need for periodic maintenance or replacement of degrading capacitor components.
3Productivity
If complex circuitry is used to control LED strings, then performance is improved, but device complexity increases
Solution Approach 1:
The patent segments the LED string into multiple independently controllable sections. Each section can be selectively activated or shorted by dedicated power switches, allowing simplified control of individual segments rather than complex control of the entire string. This modular segmentation reduces overall circuit complexity while maintaining high performance.
Solution Approach 2:
The patent introduces dynamic control through power switches that can rapidly change the circuit configuration. The control circuit dynamically adjusts which LED sections are active based on operating conditions, enabling flexible performance optimization without requiring permanently complex circuitry. The dynamic switching simplifies the average circuit state while providing high-performance capability when needed.
4Speed
If high-frequency power switching is used for control, then response speed is improved, but electromagnetic interference increases
Solution Approach 1:
The patent changes the switching frequency parameter to operate at lower frequencies that provide adequate response speed while minimizing electromagnetic interference. By optimizing the switching frequency within an appropriate range rather than using maximum possible frequencies, the system achieves good response performance without generating excessive EMI.
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
This solution achieves high efficiency, reliability, and reduced flicker with minimal components, extending mean time to failure and maintaining light output stability across varying line voltages without high-frequency power switching.
Implementation Method 1
A circuit includes a rectifier, a string of series-connected LEDs, and an integrated circuit
Implementation Method 2
The integrated circuit includes a plurality of power switches. Each power switch is coupled so that it can separately and selectably short out a corresponding one of several groups of LEDs in the LED string
Implementation Method 3
Light-Emitting Diodes or LEDs are increasingly being used for general lighting purposes
Data Source
AI summary
An LED lamp with an integrated circuit, a rectifier, and a string of series-connected LEDs rectifies an incoming AC signal. The integrated circuit includes power switches that can separately and selectably short out a corresponding one of several groups of LEDs in an LED string across which the rectified AC signal is present. As the voltage across the string increases, the integrated circuit controls the power switches to increase the number of LEDs through which current flows, whereas as the voltage across the string decreases the integrated circuit controls the power switches to decrease the number of LEDs through which current flows. The flow of LED string current is broken to reduce flicker. Alternatively, a valley fill capacitor peaks LED current during the valleys of the incoming AC signal to reduce flicker. LED current is regulated to provide superior efficiency, reliability, power-factor correction, and lamp over-voltage, -current, and -temperature protection.