LED Lighting Device Chopper Circuit Stabilization
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Solution Overview
Problem
Existing LED lighting devices take a long time for the operating power of the output controller to stabilize, leading to increased power losses due to steep control current increases.
Innovation Solution
An LED lighting device with a chopper circuit including a series circuit of an inductance element and a capacitor, where a switching element is controlled to reduce current during startup and use the secondary coil voltage for discharging, allowing the output control unit to stabilize power efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the control current is designed to be steeply increased, then the operating power stabilizes faster, but power losses in the operation controller increase
Solution Approach 1:
The patent applies periodic action by controlling the switching element to operate in PWM (pulse width modulation) mode, where the switching element is turned on and off periodically. This allows the control current to increase rapidly through controlled pulses rather than a continuous steep rise, achieving fast stabilization while reducing power losses through the periodic nature of the switching action.
Solution Approach 2:
The patent changes the parameter of current supply mode by using a current detecting resistor to detect the current flowing through the LED unit and feedback control to adjust the switching element's duty cycle. This dynamic parameter adjustment allows the system to achieve fast stabilization without the excessive power losses associated with a continuously steep current increase.
2Stability of the object's composition
If a large current is supplied to the LED unit during startup, then the capacitance element voltage increases smoothly, but the operating power stabilization time increases
Solution Approach 1:
The switching element's periodic on-off action creates controlled current pulses that charge the capacitance element. This periodic charging action allows the voltage to increase smoothly through the capacitance element while the overall stabilization process remains fast due to the high-frequency switching nature, resolving the contradiction between smooth voltage increase and fast stabilization.
Solution Approach 2:
The patent implements preliminary action by using the operation controller to preemptively control the switching element's on-off timing based on feedback from the current detecting resistor. This preliminary control ensures that current is supplied in an optimized manner from the start, achieving both smooth voltage increase in the capacitance element and reduced stabilization time.
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 reduces the time for the operating power to stabilize and decreases power losses in the output control unit by controlling the switching element's on and off times based on the voltage generated in the secondary coil.
Implementation Method 1
by using a voltage generated in a secondary coil of the inductance coil as an operating voltage of the output control unit
Implementation Method 2
a capacitance element connected between a cathode of the backward current blocking diode and the low-voltage port of the DC power supply
Data Source
Figure 1~2(c)
Figure 3(a)~4
AI summary
An LED lighting device includes a converter for converting a power source voltage into a DC voltage and outputting it to an LED unit; and a controller for controlling an output of the converter. The converter has a chopper circuit including a series circuit of an inductance element and a capacitor; a switching element connected to the inductance element in series and turned on/off by the controller; and a diode as discharging path of the inductance element during an OFF state of the switching element. The controller controls an on/off time of the switching element such that a current supplied to the LED unit during a specific time period after a lighting operation is started becomes smaller than a current supplied to the LED unit in a steady state by using a voltage generated in a secondary coil of the inductance coil as an operating voltage thereof.