Power Converter with Integrated Isolation for LED Loads
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Solution Overview
Problem
Conventional power converters for LCD-TVs perform multiple power conversions, leading to high power consumption and increased costs due to unnecessary transformer isolation and eddy current losses, while also requiring complex voltage management for LED lighting.
Innovation Solution
A power converter design that reduces the number of power conversions by using a first DC converter to convert AC voltage to DC, with a second DC converter isolating and regulating the voltage for an LED group load, incorporating a transformer for isolation and a current detection circuit with error amplification and signal transmission to control the power transfer efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple power conversions are performed (AC-DC, DC-DC, DC-AC) to achieve electrical isolation and voltage regulation, then the power conversion capability and electrical isolation are improved, but the power consumption increases and efficiency decreases
Solution Approach 1:
The patent combines multiple power conversion functions into a single integrated power conversion unit. The AC power supply is directly converted to DC voltage that simultaneously provides both the high voltage for LED backlight illumination and the low voltage for driving circuits, eliminating the need for separate DC-DC conversion stages and reducing total power loss while maintaining electrical isolation through the integrated transformer design
Solution Approach 2:
The power conversion unit performs multiple functions simultaneously: it provides electrical isolation between primary and secondary sides, generates high voltage for LED backlight, supplies low voltage to driving circuits, and enables dimming control. This multi-functionality eliminates the need for separate dedicated power conversion circuits for each function, reducing overall power consumption
2Manufacturing precision
If multiple power conversion stages are used to achieve voltage regulation and electrical isolation, then the power conversion precision is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple power conversion stages into a single integrated unit with one transformer and one control circuit. The transformer provides both electrical isolation and voltage transformation in a single component, while the control circuit simultaneously regulates both high voltage (for LEDs) and low voltage (for driving circuits), significantly reducing device complexity while maintaining voltage regulation precision through unified control
Solution Approach 2:
The integrated power conversion unit performs multiple functions: electrical isolation, high voltage generation for LEDs, low voltage generation for driving circuits, and dimming control. This multi-functional design eliminates the need for separate dedicated circuits for each function, reducing overall device complexity while maintaining precise voltage regulation through centralized control
3Reliability
If separate DC converters are used for backlight illumination and driving circuits, then the electrical isolation is improved, but the cost increases due to additional transformers and components
Solution Approach 1:
The patent combines the power conversion circuits for backlight illumination and driving circuits into a single integrated unit sharing one transformer. The transformer's secondary side provides both the high voltage for LEDs and the low voltage for driving circuits through appropriate tapping or rectification circuits, eliminating the need for separate transformers and reducing component count, which lowers manufacturing cost while maintaining electrical isolation between primary and secondary sides
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 design reduces power consumption and costs by minimizing power conversions and eliminating the need for high-cost transformer isolation, while ensuring efficient and isolated power delivery to LED loads, thus providing a cost-effective and efficient power conversion solution.
Implementation Method 1
a transformer configured to isolate a primary side and a secondary side from each other
Implementation Method 2
a switching element disposed on the primary side, and configured to transfer power to the secondary side through the transformer by being turned on/off according to the control signal transmitted from the signal transmission isolation element
Data Source
AI summary
The present invention includes a first DC converter converting AC voltage, into DC voltage while correcting a power factor, and a second DC converter electrically isolating the first DC converter from an LED group load, and converting the DC voltage, into a predetermined DC voltage and supply the resultant voltage to the LED group load. The second DC converter includes a current detection circuit disposed on the secondary side, and detecting current flowing into the LED group load, an error amplifier amplifying an error between a detected current value detected and a reference current value, a signal transmission isolation element transmitting a control signal based on an output signal from the error amplifier, to the primary side, and a switching element transferring power to the secondary side through the transformer by being turned on/off according to the control signal.