LED Driver Circuit with Dual Current Setting for Fine Dimming
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Solution Overview
Problem
Existing LED driving devices face challenges in performing fine dimming control, especially in deep dimming ranges, due to pulsed current flow leading to flicker and limited pulse width adjustment, making gradual dimming adjustments difficult.
Innovation Solution
An LED driving device with a dimming controller that generates a dimming signal and uses a converter controller, first and second current setting circuits to adjust the output current range, allowing for fine control by switching between ON and OFF states of the second current setting circuit based on the dimming signal, thereby minimizing flicker and enabling gradual dimming adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PWM control with pulsed current is used for LED dimming, then energy saving and brightness control are achieved, but flicker occurs in deep dimming ranges and fine adjustment becomes difficult
Solution Approach 1:
The patent dynamically switches between two current setting circuits (first and second) based on the dimming signal range. When the dimming signal indicates deep dimming, the system switches to the second current setting circuit which provides finer current adjustment capability, thereby eliminating flicker in low brightness ranges while maintaining effective dimming control across the full brightness spectrum.
Solution Approach 2:
The patent changes the current adjustment parameter range by selecting different current setting circuits. The first current setting circuit operates in a higher current range for normal brightness, while the second current setting circuit operates in a lower current range with finer resolution for deep dimming, allowing the system to adapt its parameter range to the required brightness level and eliminate flicker.
2Illumination intensity
If PWM control with pulsed current is used for LED dimming, then brightness control is achieved, but fine adjustment in deep dimming ranges becomes difficult due to limited pulse width variable-step
Solution Approach 1:
The system dynamically selects between two current setting circuits based on the required dimming level. For deep dimming ranges, the second current setting circuit is activated which provides finer current adjustment steps, enabling precise brightness control in low light conditions where the first circuit's larger adjustment steps would cause noticeable brightness jumps and make fine adjustment difficult.
Solution Approach 2:
The patent segments the dimming control range into two distinct zones handled by different current setting circuits. The first circuit handles normal to high brightness ranges with coarser adjustment steps, while the second circuit handles deep dimming ranges with finer adjustment steps. This segmentation allows each circuit to be optimized for its specific range, achieving fine adjustment precision where needed without compromising overall system simplicity.
Data Source
AI summary
An LED driving device that performs a dimming operation of an LED module, the device includes: a dimming controller that receives the dimming instruction signal and generates a dimming signal; and a driving circuit that supplies an output current to the LED module based on the dimming signal generated by the dimming controller, wherein the driving circuit unit includes: a converter controller that generates a drive signal based on the dimming signal and outputs the drive signal to a first switching element; a first current setting circuit; and a second current setting circuit that is connected in parallel to the first current setting circuit, and wherein the dimming controller controls an operating state of the second current setting circuit to switch an adjustment range of the output current and a change characteristic of the output current in response to the dimming signal.