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參數(shù)資料
| 型號(hào)： | LM2794 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Current Regulated Switched Capacitor LED Supply with Analog and PWM Brightness Control |
| 中文描述： | 電流調(diào)節(jié)開(kāi)關(guān)電容LED電源與模擬和PWM亮度控制 |
| 文件頁(yè)數(shù)： | 9/16頁(yè) |
| 文件大?。?/td> | 487K |
| 代理商： | LM2794 |
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Functional Block Diagram
20028530
Application Information
CIRCUIT DESCRIPTION
The LM2794/5 is a 1.5x/1x CMOS charge pump with four
matched constant current outputs, each capable of driving
up to 20mA through White LEDs. This device operates over
the extended Li-Ion battery range from 2.7V to 5.5V. The
LM2794/5 has four regulated current sources connected to
the device’s 1.5x charge pump output (P
OUT
). At input volt-
ages below 4.7V (typ.), the charge-pump provides the
needed voltage to drive high forward voltage drop White
LEDs. It does this by stepping up the P
OUT
voltage 1.5 times
the input voltage. The charge pump operates in Pass Mode,
providing a voltage on P
OUT
equal to the input voltage, when
the input voltage is at or above 4.7V (typ.). The device can
drive up to 80mA through any combination of LEDs con-
nected to the constant current outputs D
1
-D
4
.
To set the LED drive current, the device uses a resistor
connected to the I
SET
pin to set a reference current. This
reference current is then multiplied and mirrored to each
constant current output. The LED brightness can then be
controlled by analog and/or digital methods. Applying an
analog voltage in the range of 0V to 3.0V to the Brightness
pin (BRGT) adjusts the dimming profile of the LEDs. The
digital technique uses a PWM (Pulse Width Modulation)
signal applied to the Shutdown pin (SD). (see
I
SET
and
BRGT PINS
section).
SOFT START
Soft start is implemented internally by ramping the reference
voltage more slowly than the applied voltage. During soft
start, the current through the LED outputs will ramp up in
proportion to the rate that the reference voltage is being
ramped up.
L
www.national.com
9
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參數(shù)描述 |
|---|---|
| LM2794BL | 功能描述:IC LED DRVR WHT BCKLT 14USMD RoHS:否 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動(dòng)器 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 恒定電流:- 恒定電壓:- 拓?fù)?PWM，切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅(qū)動(dòng)器:是 類型 - 主要:背光 類型 - 次要:白色 LED 頻率:642kHz 電源電壓:2.7 V ~ 5.5 V 輸出電壓:5V 安裝類型:表面貼裝 封裝/外殼:10-VFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:10-VSON 包裝:剪切帶 (CT) 工作溫度:-30°C ~ 85°C 產(chǎn)品目錄頁(yè)面:1371 (CN2011-ZH PDF) 其它名稱:BD1603NUV-E2CT |
| LM2794BL NOPB | 制造商:Texas Instruments 功能描述:LED DRVR 4Segment 3.3V/5V 14-Pin uSMD T/R |
| LM2794BLX | 制造商:Texas Instruments 功能描述: |
| LM2794EVAL | 功能描述:電源管理IC開(kāi)發(fā)工具 EVAL KIT FOR LM2794 RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| LM2794TL | 功能描述:IC LED DRVR WHT BCKLT 14MICROSMD RoHS:否 類別:集成電路 (IC) >> PMIC - LED 驅(qū)動(dòng)器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 恒定電流:- 恒定電壓:- 拓?fù)?升壓（升壓），切換式電容器（充電泵） 輸出數(shù):1 內(nèi)部驅(qū)動(dòng)器:是 類型 - 主要:背光 類型 - 次要:白色 LED 頻率:625kHz ~ 875kHz 電源電壓:2.7 V ~ 5.3 V 輸出電壓:5V 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-µMAX 包裝:帶卷 (TR) 工作溫度:-40°C ~ 85°C |
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