LED Driver Auxiliary Power Supply Transformer Ratio Control
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Solution Overview
Problem
Existing LED lighting drivers face challenges in efficiently generating an auxiliary power supply during all operational modes, particularly in reducing size and cost while maintaining high efficiency across dimming levels and standby states, due to the transformer ratio being non-ideal for both states, leading to significant losses.
Innovation Solution
An LED lighting driver with a switched mode power supply and an auxiliary power supply circuit featuring a power supply inductor arrangement with a switchable transformer ratio, controlled by a controller to vary the transformer ratio based on the desired lighting level, allowing efficient generation of the auxiliary supply voltage by selectively switching the second power supply inductor into or out of the circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed transformer ratio is used in the auxiliary power supply circuit, then the circuit structure is simple, but significant energy losses occur during standby mode and the auxiliary voltage is too high during normal operation
Solution Approach 1:
The patent applies the dynamics principle by making the transformer ratio adjustable rather than fixed. The auxiliary power supply circuit switches between different transformer ratios (first ratio during standby mode, second ratio during normal operation) based on the operational state, thereby optimizing energy efficiency across different modes while managing circuit complexity through controlled adaptability.
2Loss of energy
If the transformer ratio is optimized for standby mode, then energy losses are reduced during standby, but the auxiliary supply voltage becomes too high during normal operation
Solution Approach 1:
The patent implements dynamic adjustment of the transformer ratio based on operational mode. During standby mode, a first transformer ratio is used to minimize energy losses, while during normal operation, a second transformer ratio is applied to maintain the auxiliary supply voltage at an appropriate level, thus resolving the contradiction between standby efficiency and normal operation voltage levels.
3Device complexity
If a single stage converter is used to reduce component size and cost, then PCB space and cost are reduced, but efficient auxiliary power supply generation across all operational modes becomes difficult
Solution Approach 1:
The patent applies the universality principle by designing the auxiliary power supply circuit within the single stage converter to perform multiple functions efficiently. The circuit can operate in different modes (standby and normal operation) with different transformer ratios, enabling it to maintain high efficiency across all operational modes while keeping the overall driver circuit compact and cost-effective.
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 enables efficient generation of the auxiliary supply voltage, reducing losses and maintaining desired power transfer, even during standby mode, by adjusting the transformer ratio, thus optimizing the LED lighting driver's performance across all operational modes.
Implementation Method 1
a power supply inductor arrangement magnetically coupled to the energy storage inductor
Implementation Method 2
a rectifier diode arrangement for delivering a rectified voltage to an auxiliary load
Data Source
AI summary
An LED lighting driver has a switched mode power supply which generates an auxiliary power supply. The auxiliary power supply circuit has a first power supply inductor and a second power supply inductor in series with each other. The second power supply inductor is selectively switched into or out of the auxiliary power supply circuit, thereby varying a transformer ratio to the main energy storage inductor. The switching may be made based on a light output mode or a standby mode being in operation. The standby mode then enables more efficient generation of an auxiliary supply voltage.