Current Steering Module for LED String Voltage Adaptation
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Solution Overview
Problem
Conventional control circuits for LED-based lighting products rely on electrolytic capacitors, which are prone to failure and limit the reliability of semiconductor-based lighting products due to their high voltage requirements and need for high capacitance values.
Innovation Solution
The circuitry bypasses AC-to-DC conversion and directly drives an LED array with current derived from rectified AC voltage using a current steering module, comprising holding, intermediate, and final current steering blocks, to enable current flow only when the input voltage is sufficient to activate all LEDs, thus eliminating the need for electrolytic capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional control circuits use electrolytic capacitors to handle high voltage and high capacitance requirements, then the circuit can operate at required voltage levels, but the reliability of the LED-based lighting product deteriorates due to capacitor failure
Solution Approach 1:
The patent removes electrolytic capacitors from the circuit by extracting their function through a different approach: using a current steering module with multiple current sinks that directly control LED strings without requiring high-voltage capacitive energy storage. This eliminates the reliability issue while maintaining power handling capability through active current control rather than passive energy storage.
Solution Approach 2:
The invention changes the operating parameters by switching from a high-voltage, high-capacitance architecture to a lower-voltage, active-current-steering architecture. The current steering module dynamically adjusts current distribution among LED strings based on forward voltage measurements, replacing the static high-voltage capacitor-based approach with a dynamic, measurement-based control system.
2Stability of the object's composition
If AC-to-DC conversion circuitry is used to provide stable current to LEDs, then the LEDs receive consistent current, but the circuit complexity increases and requires additional components that may fail
Solution Approach 1:
The patent introduces a current steering module as an intermediary between the power source and LED strings. This module uses microcontroller-based control to measure forward voltages and dynamically steer current to appropriate LED strings, providing stable current delivery without requiring complex analog AC-to-DC conversion circuitry. The intermediary translates simple power input into precisely controlled LED current through digital measurement and control.
3Adaptability or versatility
If the circuit is designed to handle varying voltage inputs to activate different numbers of LEDs, then the lighting adapts to available power, but the control circuitry becomes more complex
Solution Approach 1:
The patent implements feedback control by measuring the forward voltage of each LED string and using this information to determine how many strings can be actively driven by the current power level. The microcontroller continuously monitors voltage conditions and adjusts current steering accordingly, providing automatic adaptation to varying power inputs without requiring complex pre-programmed control logic or multiple circuit configurations.
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
This solution enhances the reliability and efficiency of LED-based lighting by eliminating the failure-prone electrolytic capacitors and allowing direct current steering, improving the overall performance and longevity of semiconductor-based lighting products.
Implementation Method 1
drives an LED array with current directly derived from a rectified AC voltage
Data Source
AI summary
In an embodiment, a lamp control circuit is provided. The lamp control circuit includes an intermediate current steering block configured to be coupled to a cathode of a first light-emitting device of a plurality of light-emitting devices and a final current steering block configured to be coupled to a cathode of a final light-emitting device of the plurality of light-emitting devices. The final current steering block is configured to disable the intermediate current steering block and conduct current when a voltage input to the plurality of light-emitting devices is sufficient to activate all of the plurality of light-emitting devices.