Multichannel LED Driver with Feedback Current Control
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Solution Overview
Problem
Existing lighting units with multiple LED channels face energy losses and complex control schemes due to the use of shunts for achieving desired color effects, leading to inefficient power management and control.
Innovation Solution
A lighting unit with a driver that includes a DC/DC converter, a flyback converter, a buck converter, a pulse width modulator, and a feedback device, which allows for independent and efficient control of current through each channel, maintaining desired light levels despite changes in supply voltage and load, using a feedback loop to adjust the output voltage based on current sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a shunt is used to divert current through selected LEDs to achieve desired color effects, then color control is achieved, but energy loss increases and control complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the secondary winding of the flyback transformer provides a control signal that is fed back to the primary switching device. This feedback loop enables automatic regulation of current distribution through different LED channels, achieving desired color effects while optimizing energy efficiency by eliminating the need for additional shunt components that cause energy loss.
Solution Approach 2:
The flyback transformer's secondary winding serves multiple functions: it provides voltage transformation for LED driving and simultaneously generates the control signal for current regulation. This multi-functionality eliminates the need for separate control circuits and shunt components, reducing energy loss while maintaining color control capability.
2Adaptability or versatility
If a shunt is used to divert current through selected LEDs to achieve desired color effects, then color control is achieved, but control complexity increases
Solution Approach 1:
The patent merges the voltage transformation function and the control signal generation function into a single flyback transformer structure. The secondary winding simultaneously provides the output voltage for LED driving and generates the feedback control signal, eliminating the need for separate control circuits and simplifying the overall control architecture.
Solution Approach 2:
The feedback signal derived from the secondary winding of the flyback transformer enables automatic regulation of current distribution through different LED channels. This self-regulating mechanism reduces control complexity by eliminating the need for complex external control circuits while maintaining precise color control capability.
3Adaptability or versatility
If a linear shunt is used to control current through LED channels, then color effects are achieved, but power loss increases
Solution Approach 1:
The feedback mechanism using the secondary winding of the flyback transformer enables efficient regulation of current through LED channels without requiring linear shunts. The feedback control allows for precise current management that minimizes power loss while achieving desired color effects through optimized current distribution.
Solution Approach 2:
The patent utilizes the flyback converter's ability to dynamically adjust voltage and current parameters through switching control. By changing the duty cycle and switching frequency, the system can efficiently regulate power delivery to different LED channels, eliminating the need for linear shunts that dissipate power and achieving color effects with minimal power loss.
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 and precise control of LED channels, reducing energy losses and simplifying the control scheme, allowing for consistent light output and color effects while minimizing power wastage and complexity.
Implementation Method 1
a flyback converter, configured to receive a first DC voltage and to output a second DC voltage
Implementation Method 2
a buck converter, configured to receive the second DC voltage and to generate an output voltage that causes a first current to flow through the first channel of LEDs and a second current to flow through the second channel of LEDs
Implementation Method 3
a first channel of first light emitting devices (LEDs) connected in series with each other; a second channel of second LEDs connected in series with each other
Data Source
AI summary
A lighting unit includes at least two channels of light sources, and a driver for the light sources. The driver includes a DC/DC converter and a control arrangement for controlling the current supplied to at least one of the two channels in response to a control signal produced by the DC/DC converter. Beneficially, a feedback loop controls a switching device in the DC/DC converter to maintain the light level produced by the light sources at a desired level regardless of changes in the supply voltage arid the load.