LED Control Circuit Low-Power Source Charging
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Solution Overview
Problem
Conventional LED lighting systems face challenges in controlling individual LED groups due to the inability to charge switching elements when LEDs are turned off for an extended period, leading to uncontrolled start-ups and unintended light emission.
Innovation Solution
A control circuit with a low-power source and chargeable elements connected in parallel with LED switching elements, allowing for controlled start-up and charging even when LEDs are off, ensuring proper switching state and preventing unwanted light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same power source supplies power to both LEDs and switching elements, then power consumption is simplified, but the switching elements cannot be properly controlled after LEDs have been turned off for a considerable period of time
Solution Approach 1:
The power supply system is segmented into two independent parts: the main power source for LEDs and a separate low-power source for switching elements. This segmentation allows the switching elements to be controlled independently regardless of LED operation state, resolving the reliability issue while maintaining reasonable overall complexity.
Solution Approach 2:
The low-power source pre-charges the chargeable elements (capacitors) associated with switching elements before the LEDs are turned on. This preliminary charging ensures that switching elements remain controllable even after LEDs have been off for extended periods, preventing the control failure described in the contradiction.
2Ease of operation
If a capacitor is used to supply gate-source voltage for switching elements, then switching control is enabled, but the capacitor cannot be charged when the corresponding LED is turned off, leading to voltage loss due to leakage currents
Solution Approach 1:
A low-power source acts as an intermediary charging mechanism for the capacitors associated with switching elements. When LEDs are turned off and cannot charge their corresponding capacitors, the low-power source steps in to maintain the voltage, preventing voltage loss from leakage currents and ensuring continuous controllability.
Solution Approach 2:
The system uses the low-power source to periodically refresh and maintain the charge on capacitors during periods when LEDs are off. This self-service mechanism ensures that the capacitors remain charged without requiring continuous LED operation, resolving the energy usage problem while maintaining ease of operation.
3Loss of energy
If LEDs are turned off for a considerable period of time, then energy consumption is reduced, but the initial state of LEDs after power is turned on becomes uncontrolled and cannot be adapted based on user input
Solution Approach 1:
Before the main power is supplied to LEDs, the low-power source performs preliminary charging of the capacitors associated with switching elements. This preliminary action ensures that all switching elements are in a known, controllable state when power is first applied, enabling user-defined start-up configurations even after extended off periods.
Solution Approach 2:
The control unit monitors the state of switching elements and capacitors, and uses feedback to determine the appropriate start-up configuration. This feedback mechanism allows the system to adapt the initial LED state based on user input and system conditions, resolving the adaptability issue while maintaining energy efficiency during off periods.
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
Enables controlled and consistent start-up of LED groups, allowing for precise control over brightness, intensity, and color, independent of the initial circuit state, and prevents unintended light emission by ensuring chargeable elements remain charged.
Implementation Method 1
N chargeable elements each connected between a corresponding pair of the connection terminals, and configured to be in parallel with both a corresponding LED switching element and a corresponding LED group, wherein each chargeable element enables, when charged, the corresponding LED switching element to switch from the first state to the second state
Data Source
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Figure 3a
AI summary
According to a first aspect of the invention, a control circuit and method are provided for a controlled start-up of N LED groups, wherein the control circuit comprises a LED switching element and a chargeable element in parallel with each LED group, and a low- power source, and wherein the method comprises a step of prior to supplying power to the LED groups, setting the LED switching elements in a second state which corresponds with the LED group being off, by charging the chargeable elements with the low-power source. According to a second aspect a control circuit and method are provided for controlling X LED groups, wherein the control circuit comprises a LED switching element and a chargeable element in parallel with each LED group, wherein the top of a lower chargeable element is connected via a diode with the top of a higher chargeable element. According to a third aspect of the invention, a control circuit and method are provided for controlling M LED groups, wherein the control circuit comprises a LED switching element and a chargeable element in parallel with each LED group, and a switch, wherein the switch has a lighting mode wherein current flows through the LED groups or the corresponding LED switching elements, and a charging mode wherein current flows to the chargeable elements, thereby charging the chargeable elements.