Switching Converter Start-Up Time Control via Discharge Circuit
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Solution Overview
Problem
Semiconductor light sources, such as LEDs, have a short start-up time that can cause disharmony when used with traditional lamps, and it is desirable to set a longer start-up time for LED light sources to match the lighting time of fluorescent or incandescent lamps.
Innovation Solution
A switching converter is designed with a discharge circuit that adjusts the charge speed of a capacitor, allowing for the setting of the start-up time by controlling the discharge current, which includes a discharge transistor and a bias circuit to vary the discharge current based on the input voltage, enabling the extension of the start-up time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the LED light source is used with a short start-up time, then the LED can be turned on quickly, but it causes disharmony when used with traditional lamps like fluorescent or incandescent lamps
Solution Approach 1:
The patent applies the dynamics principle by making the start-up time adjustable rather than fixed. The control circuit can dynamically set the start-up time based on different operating conditions and lamp types, allowing the LED lighting system to adapt between quick start-up mode and traditional lamp compatibility mode, thus resolving the contradiction between speed and adaptability
Solution Approach 2:
The patent changes the time parameter of the start-up process. By introducing a controllable time delay mechanism in the control circuit, the start-up time can be adjusted from short (for quick response) to long (for compatibility with traditional lamps), allowing the system to optimize performance based on specific application requirements
2Duration of action of moving object
If a discharge circuit is added to adjust capacitor charge speed, then the start-up time can be extended, but the device complexity increases
Solution Approach 1:
The patent merges the discharge circuit functionality with the existing control circuit. The control circuit integrates both the charging control and discharge control functions, allowing the start-up time adjustment to be achieved through software/control logic rather than adding a completely separate hardware subsystem, thus minimizing the increase in device complexity
Solution Approach 2:
The control circuit is designed to perform multiple functions: it controls the switching transistor for power conversion, manages the capacitor charging process, controls the discharge circuit for start-up time adjustment, and adapts to different lamp types. This multi-functionality reduces the need for separate dedicated circuits, thereby limiting the complexity increase while achieving start-up time extension
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 allows for a longer start-up time of the LED light source, comparable to traditional lamps, by adjusting the discharge current, thereby synchronizing the lighting time with other types of lamps.
Implementation Method 1
a first capacitor configured to generate a power source voltage for the control circuit between both ends of the first capacitor
Implementation Method 2
a start-up circuit installed between an input line to the switching converter and the first capacitor and configured to charge the first capacitor with an input voltage of the input line
Implementation Method 3
a discharge circuit configured to discharge the first capacitor when the switching converter is started up
Data Source
AI summary
A switching converter for supplying power to a load, includes: an output circuit including at least a switching transistor, an inductive element, and a rectifying element configured to rectify a current flowing to the inductive element according to switching of the switching transistor; a control circuit configured to drive the switching transistor; a first capacitor configured to generate a power source voltage for the control circuit between both ends of the first capacitor; a start-up circuit installed between an input line to the switching converter and the first capacitor and configured to charge the first capacitor with an input voltage of the input line; and a discharge circuit configured to discharge the first capacitor when the switching converter is started up.