LED Driver Adaptive Mode Switching for Standby Power
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Solution Overview
Problem
Existing LED drivers face inefficiency and increased cost due to high standby power consumption when the light unit is turned off, as they require an additional power source beyond the transformer, leading to inefficient circuit operation and added costs.
Innovation Solution
An LED driver with a switch mode power supply that operates in two modes: one for regulated current and another for regulated voltage, using the same power supply to provide auxiliary power during standby mode, thereby reducing component count and power consumption by deriving power from the LED arrangement's voltage, which is insufficient to turn on the LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate auxiliary power source is used during standby mode, then the controlling unit can maintain operation, but the standby power consumption increases and circuit cost increases
Solution Approach 1:
The patent merges the auxiliary power supply function with the existing transformer by utilizing the rectified voltage from the primary side of the transformer. Instead of using a separate auxiliary power source, the system combines the power supply function into the existing transformer structure, reducing component count and standby power consumption while maintaining controlling unit operation during standby mode
Solution Approach 2:
The transformer is given multiple functions: it serves both as the main power transformer for the LED driver and as the source of auxiliary power during standby mode. The primary side rectified voltage is used to power the controlling unit, eliminating the need for a dedicated auxiliary winding or separate power source, thus achieving multi-functionality with existing components
2Reliability
If a separate auxiliary power source is used during standby mode, then the controlling unit can maintain operation, but the circuit complexity and cost increase
Solution Approach 1:
The patent merges the auxiliary power supply function with the existing transformer by utilizing the rectified voltage from the primary side of the transformer. Instead of using a separate auxiliary power source, the system combines the power supply function into the existing transformer structure, reducing component count and standby power consumption while maintaining controlling unit operation during standby mode
Solution Approach 2:
The patent extracts the auxiliary power function from the traditional separate auxiliary winding or dedicated power source and relocates it to utilize the existing transformer's primary side rectified voltage. This extraction eliminates unnecessary components and simplifies the circuit while maintaining the required functionality
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 low standby power consumption and cost by using a single stage design with high efficiency during normal operation and adaptive mode switching, ensuring the LED driver maintains auxiliary power without activating the LED, thus meeting stringent power requirements.
Implementation Method 1
a switch mode power supply which includes a transformer having a primary side, a first secondary side adapted to connect to an LED arrangement, and a second secondary side
Data Source
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AI summary
An LED driver uses a switch mode power supply either to provide a regulated LED current (in a first mode) that connects directly to the LED arrangement or a regulated LED voltage (in a second mode) to an LED output terminal. An auxiliary power supply is either based on an auxiliary secondary side (i.e. an auxiliary secondary side winding) when in the first mode, or it is based on the regulated LED voltage when in the second mode. The LED driver further comprises an input adapted to receive a standby command for the driver, wherein the main controlling unit is adapted to control the driver in the second mode when receiving the standby command for the driver. In this way, the driver has a single shared stage which can operated in a regulated current (i.e. constant current) mode to drive the LED arrangement directly or a regulated voltage (i.e. constant voltage) mode. It can adaptively change between modes to improve the standby power efficiency. When the load is turned on (e.g. a first mode), the driver may function in constant current mode, and when the load is turned off (e.g. a second, standby mode), the driver works in constant voltage mode with the output voltage stepped down so that not sufficient to turn on the LED arrangement to be driven by the driver but enough to provide auxiliary power via the auxiliary power supply, in order to improve the auxiliary power efficiency.