Boost PFC Circuit Variable Resistor ECG Compatibility
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Solution Overview
Problem
Existing boost power factor correction (PFC) circuits are not compatible with electronic ballasts (ECG) due to differences in current and voltage output, limiting their use to mains AC and conventional ballasts (CCG) only.
Innovation Solution
A boost PFC circuit with an equivalent variable resistor and MOSFET, controlled by a PFC controller, adjusts resistance based on output voltage to maintain compatibility with mains AC, CCG, and ECG power supplies, allowing the circuit to operate effectively across varying voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed resistance value is used in the PFC circuit, then the circuit design is simple, but the circuit cannot be compatible with different power supply types (mains AC, CCG, ECG)
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed resistance with a variable resistance that can be dynamically adjusted based on the power supply type. The equivalent variable resistor changes its resistance value according to whether the power supply is mains AC, CCG, or ECG, allowing the PFC circuit to adapt to different operating conditions while maintaining compatibility across all power supply types.
Solution Approach 2:
The patent implements parameter changes by modifying the resistance value of the equivalent variable resistor based on the detected power supply type. When mains AC or CCG is detected, the resistance is set to a first value; when ECG is detected, the resistance is set to a second value. This parameter adjustment enables the circuit to optimize its performance for each specific power supply type.
2Adaptability or versatility
If the resistance is adjusted to accommodate ECG power supply, then compatibility with ECG is achieved, but the power factor correction performance may deteriorate for mains AC and CCG
Solution Approach 1:
The patent resolves this contradiction by dynamically changing the resistance parameter based on the power supply type. When ECG is detected, the resistance is adjusted to a second value optimized for ECG operation. When mains AC or CCG is detected, the resistance is set to a first value optimized for those power supplies. This conditional parameter adjustment ensures optimal power factor correction performance for each power supply type while maintaining universal compatibility.
Solution Approach 2:
The patent employs feedback mechanisms to detect the power supply type and accordingly adjust the resistance value. The control circuit monitors the input characteristics and provides feedback to the equivalent variable resistor, enabling it to switch between different resistance values. This feedback loop ensures that the circuit automatically selects the appropriate resistance value to maintain high power factor correction performance regardless of the power supply type.
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 compatibility with mains AC, CCG, and ECG power supplies, ensuring high power factor correction and adaptability in LED driving circuits, thereby expanding the applicability of LED lighting devices.
Implementation Method 1
The equivalent variable resistor comprises a Metal-Oxide-Semiconductor field-effect transistor (MOSFET). The output voltage generated by the sampling circuit is connected to the gate of the MOSFET. The resistance of the equivalent variable resistor varies in response to operating conditions of saturated conduction and linear conduction of the MOSFET.
Data Source
AI summary
A boost power factor correction circuit, a driving circuit for light-emitting diodes and a lighting device are provided. The boost power factor correction circuit includes: a PFC controller; a PFC switch controlled by an output of the PFC controller; and an equivalent variable resistor connected between the PFC switch and the ground. A feedback current input of the PFC controller is connected to a node between the PFC switch and the equivalent variable resistor. The resistance of the equivalent variable resistor is controlled by the output voltage of the PFC circuit. In case that the PFC circuit operates under an mains AC or CCG input, the resistance keeps constantly minimum, and in case that the PFC circuit operates under an ECG input, the resistance increases as the output voltage of the PFC circuit decreases. The boost power factor correction circuit, the driving circuit for light-emitting diodes and the lighting device according to the present disclosure are able to be compatible with mains AC, CCG and ECG power supplies.