Switching Converter Circuit for LED Drivers
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Solution Overview
Problem
Existing power supplies for medium and high-power LED light sources face challenges with complex controllers, limited output voltage dynamic, low efficiency, reliability issues due to high electric stress, and high costs, particularly in two-stage topologies using LLC or flyback switching converters.
Innovation Solution
A switching converter circuit with a pair of MOSFETs and an integrated circuit that provides high galvanic insulation, allows current control through voltage measurement, and employs a control loop with filters and an optoisolator to achieve efficient power conversion and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a two-stage power supply with LLC resonant converter is used, then efficiency is improved, but device complexity and cost increase due to complex controllers
Solution Approach 1:
The patent extracts the complex control functions from the power conversion stage and places them in a separate optical isolation stage. The microcontroller unit (MCU) handles high-level control decisions while the PWM generator handles low-level switching control, separating complex control logic from the high-frequency switching operations.
Solution Approach 2:
The patent introduces an optical isolation stage as an intermediary between the control circuit and the power conversion stage. This optical coupling allows control signals to be transmitted while providing galvanic isolation, enabling efficient control without direct electrical connection between stages.
2Device complexity
If a two-stage power supply with flyback switching converter is used, then device complexity is reduced, but reliability deteriorates due to high electric stress on components
Solution Approach 1:
The optical isolation stage acts as a mediator that transmits control signals without allowing high-voltage transients and electric stress to propagate from the power conversion stage to the control circuitry, protecting sensitive components.
Solution Approach 2:
The control system is segmented into multiple independent modules: MCU for control logic, optical isolation stage for signal transmission, and PWM generator for switching control. This segmentation isolates faults and prevents cascading failures.
3Adaptability or versatility
If a third stage of post-regulation is inserted, then output voltage dynamic is improved, but efficiency deteriorates drastically and costs increase
Solution Approach 1:
The patent implements dynamic control through the PWM generator that adjusts switching duty cycles in real-time based on load conditions and output requirements, enabling wide output voltage dynamic range without additional regulation stages.
Solution Approach 2:
The system achieves output voltage dynamic by changing the switching parameters (duty cycle, frequency) of the power converter rather than adding post-regulation stages, maintaining high efficiency across the full operating range.
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 enhances efficiency, reliability, and reduces costs by minimizing power dissipation and addressing parasitic parameter effects, improving performance and voltage dynamic for medium and high-power LED light sources.
Implementation Method 1
an optoisolator connected to the second amplification block and the summing node
Implementation Method 2
the switchings of the MOSFET occur at nil voltage and the intrinsic diodes of each MOSFET begin to conduct before the switching on of the MOSFET, thus preventing dissipation of power due to the evacuations of the junctions
Implementation Method 3
a pair of coupled inductors, represented by the equivalent of a double-bipolar model which comprises an ideal transformer T
Data Source
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AI summary
A switching converter circuit comprises at least an input terminal (IN1) for connecting to a continuous voltage source (VDCbus), an integrated control circuit (20), a pair of field effect transistors (QH, QL) connected to the integrated control circuit (20), a pair of coupled inductors (10) connected to the pair of field effect transistors (QH, QL), a diode (D) connected to the pair of field effect transistors (QH, QL), a pair of capacitors (Cn, Cled), and a first output terminal (OUT1). The converter circuit (1) further comprises a control loop (100) for controlling a current in output from the circuit via the first output terminal (OUT1).