LED Driver Circuit Complementary Half-Cycle Operation
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Solution Overview
Problem
Existing LED driver designs face challenges in series connection of LED lamps due to positive impedance, leading to unbalanced voltage and instability, particularly when two closed loop drivers are connected, resulting in abnormal driving conditions and flicker.
Innovation Solution
The implementation of a complementary operation mechanism where two LED drivers work in a time division manner, with each driver being powered during alternating half cycles of the AC input, using shorting elements controlled by a configuration circuit to prevent unbalanced voltage, allowing for closed loop feedback control and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed loop drivers are connected in series, then current control precision is improved, but voltage balance deteriorates due to positive feedback from positive impedance
Solution Approach 1:
The patent implements periodic action by alternating the operation of two LED drivers in different half-cycles of the AC input voltage. During positive half-cycles, the first driver operates while the second is shorted; during negative half-cycles, the second driver operates while the first is shorted. This periodic switching prevents simultaneous operation that would cause voltage imbalance, while still providing closed-loop current control during each active half-cycle.
Solution Approach 2:
The patent applies dynamics by making the circuit configuration changeable through controlled switching of shorting elements. The shorting elements dynamically connect or disconnect the LED drivers based on the half-cycle detection, transforming the static series connection into a dynamic time-division multiplexed system that adapts to the AC voltage polarity.
2Stability of the object's composition
If open loop drivers are used, then voltage balance is improved due to fixed input impedance, but light output regulation deteriorates
Solution Approach 1:
The patent uses periodic action to switch between two operational states: during each half-cycle, one driver operates in closed-loop mode while the other is shorted. This allows the system to achieve both voltage balance (through the alternating shorting that prevents simultaneous positive feedback) and light output regulation (through closed-loop control during active periods).
Solution Approach 2:
The patent ensures continuity of useful action by maintaining closed-loop current control during every half-cycle, just alternating between different drivers. This continuous regulation prevents light output fluctuations while the alternating shorting maintains voltage balance, avoiding the need to operate in open-loop mode.
3Use of energy by moving object
If two closed loop drivers operate simultaneously in series, then power efficiency is improved, but system stability deteriorates due to unbalanced voltage distribution
Solution Approach 1:
The patent implements periodic action by alternating the operation of two LED drivers in different half-cycles of the AC input voltage. During positive half-cycles, the first driver operates while the second is shorted; during negative half-cycles, the second driver operates while the first is shorted. This periodic switching prevents simultaneous operation that would cause voltage imbalance, while still providing closed-loop current control during each active half-cycle.
Solution Approach 2:
The patent applies dynamics by making the circuit configuration changeable through controlled switching of shorting elements. The shorting elements dynamically connect or disconnect the LED drivers based on the half-cycle detection, transforming the static series connection into a dynamic time-division multiplexed system that adapts to the AC voltage polarity.
Data Source
AI summary
A first LED driver circuit comprising: a first input interface (30) for receiving an AC power input and providing a first output, wherein said first output is adapted to be connected to a second LED driver circuit; a first LED driver (32) powered by the first output; a first shorting element (36) for shorting the first output; a first control arrangement (38) for controlling the first shorting element wherein the first control arrangement (38) is adapted to close the first shorting element (36) during only one subset of half cycles of the AC power input to short circuit the first LED driver (32) and to prevent the first LED driver (32) from being powered by the AC power input, when the second LED driver circuit is powered by the AC power input complementarily with respect to the unpowered first LED driver (32) and, open the first shorting element (36) during the other subset of half cycles to allow the AC power input to power the first LED driver (32), when the second LED driver circuit is not powered by the AC power input complementarily with respect to the first LED driver (32); wherein the half cycle is the positive amplitude duration or the negative amplitude duration of the AC power input This means two of the LED driver circuits may be used in series, each one is supplies by power or not complementarily based on only one subset of half cycles of the AC power input.