| Summary: | 碩士 === 元智大學 === 電機工程學系 === 99 === ABSTRACT
In the carbon reduction of environmental consensus, unlike the traditional backlighting elements (such as CCFL), the lower power consumption of the LED has become a new generation of LCD TV backlight trend. Compared to the application of monitor, TV as a larger size, they need more strings of the LED backlight modules to achieve the required brightness of the LED control and on it’s multi-serial LED strings. The first problem is the current imbalances will be encountered among LED strings. The imbalance will cause the serial current uneven brightness, and thus the image quality. How to reach a balance under the given cost and getting the current balance among the LED strings, will be a challenge to for LED driver designers.
Conventional AC load multiple drivers [ such as CCFL, EEFL ( External Electrode Fluorescent Lamp ), etc. ] often connected passive components in each group sharing the loads among AC power input, so one can achieve multiple AC load flow with current balance.
This thesis proposes a lower power loss and cheaper method LED driver module for a typical 60” LED TV. For balancing the multiple LED strings, the LCD-TV LED driver circuit prototype design with passive components used in the DC load current connection. In addition, the circuit outputs data and waveforms were also measured. The AC power connecting with a rectifier can provide the DC power for the DC loads. By the connection of passive components, it will get the current balance among the DC loads.
This thesis uses a LLC resonant converter design integrated with "A power supply with a H- balance LED driver for the multiple DC loads." The main purpose of the new power module for LED driver is to provide a cheaper and also efficient power supply circuit for current balance. Different from the traditional with linear structure, the new design can have current balance in each group of DC loads and the same brightness, the lower power consumption and high efficiency. The new design has relatively few components and low complexity, and substantial cost savings. With the actual measurements, we will measure and evaluate the performance of the new LED driver design with current balance circuits.
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