LED Inrush Current Control via Attenuator and Processor
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Solution Overview
Problem
Solid state light emitters, such as LEDs, face the risk of inrush current damage when first powered up due to residual charge in filter capacitors, which can disrupt continuous power supply and internal control circuits in large lighting installations, necessitating inrush current protection.
Innovation Solution
An integrated control module with an attenuator and processor is used to control the current applied to the LED array, attenuating initial current and generating control signals to manage inrush current, ensuring safe and continuous power delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a filter capacitor is used at the output of the power supply driver to maintain continuous power, then power stability is improved, but inrush current damage risk increases when the switch is opened and closed
Solution Approach 1:
The control circuit detects when the switch is opened and closes it again after a predetermined time period has elapsed, allowing the filter capacitor to discharge completely before re-closing the switch. This preliminary waiting action prevents inrush current damage by ensuring the capacitor is fully discharged before power is restored to the LED array.
Solution Approach 2:
The control circuit continuously monitors the switch state and uses this feedback to determine when to re-close the switch. By detecting the open switch condition and using this information to control the timing of switch closure, the system dynamically adjusts power delivery to prevent inrush current while maintaining continuous power supply capability.
2Object-affected harmful factors
If switching is performed at the supply side of the driver to protect against inrush current, then inrush current protection is improved, but the ability to maintain continuous power at the internal control circuit is lost
Solution Approach 1:
The control circuit acts as an intermediary between the switch and the LED array, positioned at the load side rather than the supply side. This intermediary location allows the control circuit to receive continuous power from the driver while still being able to control switch timing to prevent inrush current damage to the LED array. The control circuit thus mediates between the need for continuous power and inrush current protection.
3Adaptability or versatility
If individualized control capability is maintained in large lighting installations, then system flexibility is improved, but complexity of power control increases
Solution Approach 1:
Each lighting fixture is equipped with its own control circuit that autonomously detects switch state and controls the timing of switch closure without requiring external control signals. This self-service capability allows individualized control of each fixture while using a simple, standardized control mechanism that does not increase system complexity. Each fixture independently manages its own inrush current protection and power continuity.
Data Source
AI summary
A lighting module configured to be powered by an external driver includes a light emitting diode (LED) array, and a control circuit configured to control current initially applied by the external driver to the LED array. A lighting system includes a driver configured to provide a constant current power supply and a plurality of lighting modules coupled to the driver. Each lighting module includes a light emitting diode (LED) array, and an integrated control module including an attenuator configured to attenuate current initially applied by the driver to the LED array in response to a received control signal, and a processor configured to generate the control signal to the attenuator.