LED Driver Circuit Maintains Current Balance via Duty Cycle Feedback
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Solution Overview
Problem
Existing light emitting diode (LED) driving apparatuses face issues with current unbalance between LED channels due to voltage deviations, leading to non-uniform brightness and increased heat generation.
Innovation Solution
A light emitting diode driving apparatus that includes an alternating current to direct current converting unit, a detecting unit to monitor voltage drops across LED channels, a converting unit to digitize these values, and a driving unit to differentially set duty cycles of switching signals to maintain uniform current flow across channels, thereby reducing heat and ensuring consistent brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switching element is used to control respective LED channels with a constant current, then the LED channels can be driven, but voltage deviation between the LEDs causes current unbalance and non-uniform brightness
Solution Approach 1:
The patent implements a feedback mechanism where the controller measures the actual current in each LED channel and adjusts the duty cycle of the switching element accordingly. This closed-loop control compensates for voltage deviations between LEDs, ensuring uniform current distribution and consistent brightness across all channels.
Solution Approach 2:
The patent dynamically adjusts the duty cycle of the switching element based on real-time current measurements. Instead of using a fixed duty cycle, the system continuously adapts the switching parameters to maintain equal current distribution across LED channels with different forward voltage characteristics.
2Ease of operation
If LEDs are connected in series to form channels, then the voltage deviation between LEDs occurs, but this configuration is necessary for constant current control
Solution Approach 1:
The controller continuously monitors the current in each series-connected LED channel and uses this feedback information to adjust the duty cycle. This allows the system to maintain constant current control while compensating for the inherent voltage deviations that occur when LEDs are connected in series.
Solution Approach 2:
The patent changes the switching parameter (duty cycle) dynamically to compensate for voltage deviations in series-connected LED channels. By adjusting the duty cycle based on measured current values, the system maintains reliable current balance despite the series configuration causing voltage variations.
3Device complexity
If duty cycles are uniformly set across all LED channels, then the control is simple, but heat is generated due to voltage deviations between channels
Solution Approach 1:
The patent transitions from static uniform duty cycle control to dynamic differential duty cycle control. The controller continuously adjusts each channel's duty cycle based on real-time current measurements, optimizing heat distribution across channels while maintaining relatively simple control architecture.
Solution Approach 2:
The system changes the duty cycle parameter differentially for each LED channel based on measured current values. This parameter adjustment compensates for voltage deviations and reduces excessive heat generation in channels with higher voltage drops, while maintaining overall control simplicity.
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
The solution effectively maintains uniform brightness across LED channels and reduces heat generated due to voltage deviations, achieving stable and efficient LED operation.
Implementation Method 1
an alternating current to direct current converting unit converting input alternating current power into direct current power having a preset voltage level
Implementation Method 2
a detecting unit detecting voltage drops generated in a plurality of respective light emitting diode channels
Implementation Method 3
a plurality of light emitting diode channels each having a plurality of light emitting diodes performing a light emitting operation by receiving the driving power
Data Source
AI summary
There is provided a light emitting diode driving apparatus capable of uniformly maintaining current balance between light emitting diode channels. The light emitting diode driving apparatus includes: a DC to DC converting unit converting the direct current power into settable driving power; a detecting unit detecting voltage drops generated in each of a plurality of light emitting diode channels each having a plurality of light emitting diodes; a converting unit converting an analog value into a digital value; and a driving unit differentially setting duty cycles of switching signals according to the digital values from the converting unit to drive the plurality of light emitting diode channels.