Multi-Channel LED Synchronous Driving Circuit Without Energy Storage
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Solution Overview
Problem
Conventional methods for driving multi-channel light emitting diodes (LEDs) using AC linear direct drive type suffer from flicker issues, high power factor, and total harmonic distortion (THD) due to the requirement of energy storage elements like capacitors, which complicates the circuit and increases manufacturing costs, making them unsuitable for meeting stringent flicker regulations.
Innovation Solution
A synchronous driving circuit for multi-channel LEDs that adjusts connection states according to input voltage levels, utilizing a rectification unit, current sensor, and current mirror to provide rectified current to serially connected LEDs without energy storage elements, thereby improving flicker characteristics, power factor, and reducing THD.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If AC linear direct drive type is used without energy storage elements, then circuit complexity is reduced and manufacturing cost is lowered, but flicker occurs and percentage flicker becomes 100%
Solution Approach 1:
The patent segments the multi-channel LED driving into sequential activation phases based on input voltage levels. Different channels are activated at different voltage thresholds (e.g., first channel at 10V, second channel at 20V), transforming the simultaneous flickering problem into a phased activation approach that maintains constant current delivery while reducing circuit complexity
Solution Approach 2:
The patent implements dynamic voltage threshold detection and sequential channel activation. The control circuit dynamically adjusts which channels are active based on real-time input voltage levels, transitioning from one channel to another as voltage increases, thereby maintaining stable LED operation without requiring energy storage elements
2Object-affected harmful factors
If converter type with inductor and capacitor is used, then flicker is eliminated and constant current is output, but system configuration becomes complex and size and weight increase
Solution Approach 1:
The patent extracts and eliminates the energy storage elements (inductor and capacitor) from the conventional converter type circuit. By removing these components, the system achieves flicker elimination through alternative means (sequential channel activation based on voltage thresholds) while significantly simplifying the circuit configuration and reducing size and weight
Solution Approach 2:
The patent replaces the mechanical/electromagnetic energy storage mechanism (inductor-capacitor system) with an electronic control-based sequential activation system. Instead of storing energy physically, the system uses voltage threshold detection and controlled switching to deliver constant current, substituting a simpler electronic control approach for a more complex energy storage mechanism
3Object-affected harmful factors
If sequential driving method is used for multi-channel LEDs, then flicker index improves, but not all LEDs are driven at low voltage sections
Solution Approach 1:
The patent segments the LED channels into multiple groups with different voltage thresholds. At low voltage sections, the first channel is activated; at medium voltage, the second channel activates; at high voltage, all channels activate. This segmentation ensures continuous LED operation across the entire voltage range while maintaining low flicker index through sequential activation
Solution Approach 2:
The patent implements dynamic channel activation based on real-time voltage detection. As input voltage increases, the control circuit dynamically transitions from activating the first channel to activating the second channel, and finally to activating all channels. This dynamic adaptation ensures maximum LED driving coverage across different voltage conditions while maintaining improved flicker characteristics
4Device complexity
If conventional linear method is used, then circuit is simple, but power factor becomes low and total harmonic distortion becomes high
Solution Approach 1:
The patent incorporates voltage threshold detection feedback into the channel activation control. The control circuit continuously monitors input voltage and adjusts channel activation accordingly, creating a feedback mechanism that optimizes power factor while maintaining circuit simplicity. This feedback-based control ensures efficient power utilization across different voltage conditions
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 simplifies the overall configuration, reduces manufacturing costs, and ensures all LEDs are turned on at appropriate voltage levels without inductors or transformers, effectively addressing flicker and efficiency issues while meeting regulatory standards.
Implementation Method 1
a rectification unit receiving and rectifying an AC voltage
Implementation Method 2
a current sensor unit sensing a current flowing in the first light emitting diode
Implementation Method 3
a current mirror unit mirroring the current sensed by the current sensor unit, and supplying the mirrored current to the second light emitting diode
Implementation Method 4
a multi-channel light emitting diode unit in which a plurality of light emitting diodes are serially connected with each other, the plurality of light emitting diodes including at least a first light emitting diode and a second light emitting diode, and being driven to emit light by receiving the rectified current from the rectification unit
Data Source
AI summary
Disclosed is an apparatus for synchronous driving of multi-channel light emitting diodes capable of driving all light emitting diodes at the same time regardless of an input voltage level. The apparatus includes: a rectification unit rectifying an AC voltage; a multi-channel light emitting diode unit including at least a first light emitting diode and a second light emitting diode, and being driven by receiving the rectified current; a current sensor unit sensing a current flowing in the first light emitting diode; a current mirror unit mirroring the current sensed by the current sensor, and supplying the mirrored current to the second first light emitting diode; and a sequential current driving unit connected to the first light emitting diode and the second light emitting diode, providing a path to a current flowing in the first light emitting diode or in the second light emitting diode, and activating the current sensor unit.