Power Factor Correction Circuit Frequency Stabilization
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Solution Overview
Problem
AC direct driving circuits for LED lighting face challenges in precisely sensing the driving current due to frequency fluctuations, leading to power loss and voltage spikes, which affect the matching of input and output current timings.
Innovation Solution
A frequency adjusting circuit and method that includes a reference voltage generation unit, a sensing section determining unit, and a driving signal generation unit to generate section reference voltages and switching device driving signals, preventing voltage spikes by mirroring currents and charging/discharging capacitors to maintain a consistent frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the frequency of driving current is adjusted based on reference voltage changes, then the adaptability to different voltage conditions is improved, but the frequency stability deteriorates causing timing mismatch between input and output current
Solution Approach 1:
The patent employs feedback mechanisms where the sensed driving current information is fed back to the driving signal generation unit. This feedback loop allows the system to automatically adjust and maintain proper timing between input and output currents despite reference voltage changes, resolving the contradiction between adaptability and frequency stability.
Solution Approach 2:
The system performs self-adjustment by sensing its own driving current characteristics and automatically correcting timing mismatches. The driving signal generation unit uses the sensed information to self-regulate the switching timing, eliminating the need for external frequency stabilization while maintaining adaptability to voltage changes.
2Measurement precision
If the driving current sensing is performed to adjust frequency, then the frequency control precision is improved, but voltage spikes occur due to switch turn-on or turn-off
Solution Approach 1:
The patent introduces an intermediary sensing mechanism that measures driving current without direct contact during switching transitions. By using an intermediate sensing approach, the system avoids the voltage spikes generated by direct switching while still obtaining precise current measurement information for frequency control.
Solution Approach 2:
The system performs preliminary sensing of the driving current characteristics before switching operations occur. By anticipating the switching events and pre-adjusting sensing timing, the system captures accurate current data without being affected by the voltage spikes that occur during actual switch turn-on or turn-off moments.
3Productivity
If the timing of input and output current is mismatched due to frequency fluctuation, then the power factor correction becomes difficult, but reactive power increases causing power loss
Solution Approach 1:
The patent uses feedback from current sensing to continuously monitor and adjust the timing relationship between input and output currents. This feedback mechanism enables real-time power factor correction by synchronizing the switching timing with the AC input voltage, preventing reactive power generation and reducing power loss.
Solution Approach 2:
The system replaces traditional passive power factor correction methods with active electronic control based on sensed current information. By using electronic timing adjustment driven by sensing feedback, the system achieves dynamic power factor correction that adapts to varying operating conditions while minimizing energy loss.
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
The solution effectively stabilizes the frequency of the driving current, preventing voltage spikes and maintaining precise timing between input and output currents, thereby reducing power loss in LED lighting equipment.
Implementation Method 1
a frequency determining module configured to mirror a current having the same magnitude as that of the current flowing to the section reference voltage generation module to induce a second mirroring current, and charge or discharge a first capacitor having a first capacitance through the second mirroring current to determine a second frequency
Implementation Method 2
The reference voltage generation unit may be further configured to convert the dimming voltage into a current and mirrors the converted current to generate a first mirroring current
Implementation Method 3
The reference voltage generation unit may be further configured to convert the first mirroring current into a voltage through a digital-analog converter and generate the reference voltage through an OP amplifier
Implementation Method 4
generate the reference voltage through an OP amplifier
Data Source
AI summary
A circuit for adjusting a frequency of an AC direct lighting apparatus is provided. The circuit may include a reference voltage generation unit configured to receive a dimming voltage having a first frequency and a first voltage range, and generate a reference voltage having a second voltage range, a sensing section determining unit configured to generate first and second section reference voltages based on the reference voltage, and determine a driving current sensing section using the first and second section reference voltages, and a driving signal generation unit configured to generate a switching device driving signal having a second frequency through the determined driving current sensing section.