LED Lamp Control Circuit Dynamic Capacitance Adjustment
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Solution Overview
Problem
Existing LED lamp power supplies face challenges in maintaining high Power Factor (PF) and low Total Harmonic Distortion (THD) across varying load ranges, as the capacitance of traditional filter modules may not match load power requirements, leading to non-compliance with regulatory standards.
Innovation Solution
A control circuit for LED lamps that includes a rectifier module, a filter module, additional expansion modules, and an output control module, utilizing a duty cycle/frequency sampling circuit and switch control circuit to dynamically adjust the capacitance of the filter circuit by connecting additional filter capacitors in parallel, ensuring PF and THD values meet standards through real-time monitoring and control of PWM or PFM signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitance of the filter module is increased to maintain high PF and low THD values, then the Power Factor improves, but the device complexity increases due to additional expansion modules and control circuits
Solution Approach 1:
The patent implements dynamic capacitance adjustment by controlling switches to connect or disconnect additional filter capacitors based on real-time sampling of PWM signal duty cycle or PFM signal frequency. This dynamic adaptation allows the filter module to maintain optimal capacitance values across varying load conditions, ensuring PF and THD compliance without requiring a permanently complex circuit structure.
Solution Approach 2:
The patent changes the capacitance parameter of the filter module dynamically by switching additional capacitors in and out of the circuit. The duty cycle/frequency sampling circuit detects load variations, and the switch control circuit responds by adjusting the total capacitance value, thereby maintaining power factor compliance across different operating conditions without fixed complex architecture.
2Adaptability or versatility
If additional expansion modules are added to dynamically adjust capacitance, then the adaptability to varying load ranges improves, but the device complexity increases
Solution Approach 1:
The system achieves load range adaptability through dynamic control of capacitor switching. The duty cycle/frequency sampling circuit continuously monitors output signals, and the switch control circuit dynamically connects or disconnects additional filter capacitors based on detected load variations, enabling the circuit to adapt to different operating conditions.
Solution Approach 2:
The patent employs feedback mechanisms where the duty cycle/frequency sampling circuit samples the PWM or PFM signals and provides feedback to the switch control circuit. This feedback loop enables automatic adjustment of capacitance based on actual load conditions, achieving adaptability through intelligent control rather than complex hardwired circuitry.
3Reliability
If real-time monitoring and dynamic adjustment of filter capacitance is implemented, then the Power Factor and THD compliance improves, but the manufacturing cost increases
Solution Approach 1:
The patent achieves regulatory compliance through dynamic capacitance adjustment controlled by switch devices. By sampling PWM duty cycle or PFM frequency and responding with capacitor switching, the system maintains PF and THD within required ranges without requiring permanently complex or expensive circuit configurations.
Solution Approach 2:
The system changes the capacitance parameter dynamically based on load conditions detected through signal sampling. This parameter adjustment approach allows compliance with regulatory standards across varying operating conditions while avoiding the need for expensive fixed high-capacitance designs or complex control systems.
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 control circuit effectively adjusts capacitance to maintain compliant PF and THD values across varying loads, ensuring LED power supplies meet regulatory standards by dynamically expanding capacitance in response to changing load conditions.
Implementation Method 1
a rectifier module, a filter module connected in parallel with the output of the rectifier module
Implementation Method 2
the filter module comprising a filter capacitor C6
Implementation Method 3
the switch is a MOS transistor Q5, the MOS transistor Q5 is NPN type, and the base of the MOS transistor Q5 is connected with the switch control circuit, the drain is electrically connected to one end of the additional filter capacitor C13, and the source is grounded
Implementation Method 4
the output control module being configured to output a PWM signal or a PFM signal
Implementation Method 5
the output control module being configured to output a PWM signal or a PFM signal
Data Source
AI summary
A control circuit for LED lamps comprises a rectifier module, a filter module, at least one additional expansion module, and an output control module. The filter module comprises a filter capacitor C6. The output control module is configured to output a PWM signal or a PFM signal. Each of the additional expansion modules comprises an additional filter circuit, a switch control circuit, and a duty cycle/frequency sampling circuit. The control circuit for LED lamps provided by the present invention utilizes the duty cycle/frequency sampling circuit to monitor the duty cycle or power of the PWM signal or the PFM signal output by the output control module in real time so as to output the control signal, and the switch control circuit controls the on-off of the switch of the additional expansion circuit according to the output control signal of the duty cycle/frequency sampling circuit, so that the capacitor of the additional expansion circuit can be connected in parallel or unparallel to the filter module, in full load conditions LED power PF value and THD value can conform to the corresponding standards.