LED Driver Impedance Matching for Fluorescent Ballast Compatibility
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Solution Overview
Problem
LED illuminating apparatuses are not compatible with ballast stabilizers designed for fluorescent lamps, leading to operational issues or damage due to differing electrical characteristics.
Innovation Solution
A light source driving device with a transformer, rectifying diode, filter, and open loop preventing circuit, which matches the impedance of a fluorescent lamp to allow normal power output from the ballast stabilizer, and includes a thermistor or resistor to manage initial high impedance states, ensuring compatibility and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an LED illuminating apparatus is used with a ballast stabilizer designed for fluorescent lamps, then the device can utilize existing ballast stabilizer infrastructure, but the LED apparatus may not operate normally or components may be damaged due to electrical characteristic mismatches
Solution Approach 1:
The patent introduces an intermediary circuit between the ballast stabilizer and the LED illuminating apparatus. This intermediary circuit includes a transformer with a primary winding connected to the ballast stabilizer and a secondary winding connected to the LED apparatus. The intermediary circuit adapts the electrical characteristics from the ballast stabilizer to match the requirements of the LED apparatus, enabling compatible operation without direct connection conflicts.
Solution Approach 2:
The patent changes electrical parameters through the transformer circuit. The transformer transforms the voltage, current, and impedance levels from the ballast stabilizer output to match the LED apparatus requirements. By adjusting these electrical parameters through electromagnetic transformation, the system achieves compatibility between the fluorescent lamp ballast and LED load.
2Power
If the impedance of the LED illuminating apparatus is different from that of a fluorescent lamp, then the LED can be driven with appropriate power, but the ballast stabilizer cannot output normal power and may cause damage
Solution Approach 1:
The transformer acts as an intermediary that bridges the impedance mismatch between the ballast stabilizer and LED apparatus. The primary winding has impedance matched to the ballast stabilizer output, while the secondary winding provides the appropriate impedance for the LED apparatus, allowing normal power output from the ballast without causing damage.
Solution Approach 2:
The transformer changes the impedance parameter through electromagnetic transformation. The impedance ratio between primary and secondary windings is designed to match the ballast stabilizer output characteristics with the LED apparatus requirements, enabling the ballast to output normal power while the LED receives appropriate driving power.
3Reliability
If a transformer with specific impedance coil is used to match ballast stabilizer output, then normal power output is achieved, but the device complexity increases
Solution Approach 1:
The transformer circuit serves multiple functions simultaneously: it provides impedance matching, voltage transformation, and power isolation between the ballast stabilizer and LED apparatus. By combining these functions into a single transformer component, the patent achieves reliable normal power output while minimizing the increase in device complexity compared to using separate impedance matching and voltage regulation circuits.
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 the LED illuminating apparatus to operate normally by mimicking the electrical characteristics of a fluorescent lamp, preventing damage and ensuring stable power output from the ballast stabilizer.
Implementation Method 1
a transformer including a primary winding part including first and second external input terminals configured to receive external power from a ballast stabilizer and a coil having an impedance level set to allow the ballast stabilizer to output a normal amount of power, and a secondary winding part electromagnetically coupled to the primary winding part to transform the received external power
Implementation Method 2
a rectifying diode rectifying output power from the secondary winding part of the transformer
Implementation Method 3
a filter having an input terminal and an output terminal outputting light source driving power, configured to deliver rectified power received from the rectifying diode at the input terminal when the rectifying diode is turned on to the output terminal thereof, and storing a partial amount of the rectified power
Data Source
AI summary
A light source driving device includes a transformer, a rectifying diode, a filter, and an open loop preventing circuit. The transformer has a primary winding part including first and second external input terminals configured to receive external power from a ballast stabilizer and a coil having an impedance level set to allow the ballast stabilizer to output a normal amount of power, and a secondary winding part electromagnetically coupled to the primary winding part to transform received external power. The rectifying diode rectifies power from the secondary winding part, and the filter filters the rectified power from the rectifying diode. The open loop preventing circuit provides a closed loop to the filter such that power stored in the filter is applied to the output terminal when the rectifying diode is turned off.