回饋控制降低功率損耗的發光二極體驅動裝置

專利類型

發明

專利國別 (專利申請國家)

中華民國

專利申請案號

101100949

專利證號

I 448191

專利獲證名稱

回饋控制降低功率損耗的發光二極體驅動裝置

專利所屬機關 (申請機關)

國立臺北科技大學

獲證日期

2014/08/01

技術說明

一種回饋控制降低功率損耗的發光二極體驅動裝置，包含一主功率級電路、數個電流調整器、一偵測器及一控制單元，其主功率級電路是可提供驅動電壓加載於該等LED燈串；各電流調整器的一MOSFET元件連接於一運算放大器之輸出端及一限流電阻之間，且藉由運算放大器虛短路的特性使限流電阻上之跨壓等於調光信號，令調光信號與流經各LED燈串的電流成正比；偵測器取得該等MOSFET元件的閘極電壓且輸出一最大閘極電壓；控制單元根據最大閘極電壓之變化而產生調變量並處理為回饋電壓，使各MOSFET元件工作於其特性曲線之膝點接近飽和區以降低不必要的功率損耗。 A single-stage power-factor-corrected (PFC) flyback converter is used as the main power stage, which is controlled by a control IC named L6562 so as to driver LED strings of about 100W. For the dimming circuit to be considered, the field programmable gate array (FPGA) is used as a control kernel of LED dimming. At the same time, the gate voltage detecting circuit is added to the linear current regulator, so as to achieve LED dimming. According to the dimming command and the variation in gate voltage, the voltage reference command for the flyback converter is dynamically adjusted via a varying value created from FPGA, so as to make the voltage across the MOSFET reduced as the LED string is dimmed down.The proposed dimming method can make the voltage across the MOSFET operated at as near the knee point of the MOSFET output characteristic curve as possible, so as to reduce the power loss in the MOSFET and hence to increase the efficiency of the overall system.

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本部(收文號1080026226)同意該校108年4月26日北科大產學字第1087900115號函申請終止維護專利

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