參數(shù)資料
型號(hào): SP6648EU
英文描述: Ultra-low Quiescent Current, High Efficiency Boost Regulator
中文描述: 超低靜態(tài)電流,高效率升壓穩(wěn)壓器
文件頁數(shù): 2/5頁
文件大?。?/td> 98K
代理商: SP6648EU
USING THE EVALUATION BOARD
1) Powering Up the SP6648LED Circuit
The SP6648LED Evaluation Board
can be powered from inputs from a +1.8V to +3.2V power
supply or from 2 alkaline cells. Connect with short leads directly to the “VIN” and “GND” posts.
Plug the 1W LumiLED between the “VOUT” and “REF” posts. Unlike other boost regulators, the
part has self-protection feature. It will not be damaged when the output is open as long as there
is a low resistance from FB to GND. As shown in Figures 1 and 2, if the board is powered up
before the LumiLED is plugged in, the circuit will bring the Feedback pin to 0V and the SP6648
has a feature to set the output voltage to be 3.3V. Once the LumiLED is plugged in, the
Feedback pin will go up to 1.25V and begin to regulate. The output voltage will go from 3.3V to
3.68V (=V
F
+0.61V) accordingly (as shown in Fig. 1), where V
F
is the forward voltage of the
LumiLED. When the LumiLED is open, the Feedback pin voltage will go to 0V and the output
voltage will go to 3.3V which will protect the part (as shown in Fig 2).
Fig 1. Plug in the LumiLED
Fig. 2. Unplug the LumiLED
2) Using the J1 Jumper: Enabling the SP6648 Output and using the Shutdown Mode
The SP6648 output will be enabled if the J1 Jumper is in the top or pin 1 to 2 position. If J1 is in
the pin 2 to 3 position, the Shutdown pin is brought to GND, which puts the SP6648 in the low
quiescent Shutdown Mode.
3) Selecting the Bias Resistor
In the white LEDs application, the SP6648 is generally programmed as a current source. The
bias resistor is used to set the operating current of the white LED as equation
V
R
=
F
REF
I
b
where V
REF
is around 0.61V, I
F
is the operating current of the Lumiled. To set the operating
current to be about 350mA, R
b
is selected as 1.8 Ohm as shown in the schematic.
4) Vout Programming
The SP6648 can be programmed as either a voltage source or a current source. To program the
SP6648 as voltage source, the SP6648 requires 2 feedback resistors R
6
& R
7
to control the
output voltage. To set Vout in the voltage mode, use the equation:
V
R
7
out
61
6
R
1
.
=
V
OUT
V
OUT
V
REF
V
REF
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SP6648EU/TR 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述:
SP6648EU-L 功能描述:DC/DC 開關(guān)控制器 0.85V-4.5V 400mA temp -40C to 85C RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
SP6648EU-L/TR 功能描述:DC/DC 開關(guān)控制器 Ultra-low Quiescent High Efficiency RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
SP6648LED 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Evaluation Board Manual
SP6648LEDEB 功能描述:DC/DC 開關(guān)控制器 Ultra Low Quies Cur Hi-Eff Boost Reg RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK