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參數(shù)資料
| 型號： | LT1676 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | Wide Input Range, High Efficiency, Step-Down Switching Regulator(寬輸入范圍，高效率，步降開關(guān)穩(wěn)壓器) |
| 中文描述： | 輸入范圍寬，高效率，降壓型開關(guān)穩(wěn)壓器（寬輸入范圍，高效率，步降開關(guān)穩(wěn)壓器） |
| 文件頁數(shù)： | 6/16頁 |
| 文件大小： | 140K |
| 代理商： | LT1676 |
6
LT1676
BLOCK DIAGRA
SWDR
SWON
BOOST
SWOFF
SWDR
SWON
BOOST
1676 BD
SWOFF
LOGIC
OSC
BIAS
V
TH
V
B
V
BG
V
BG
FB
V
C
GND
SYNC
SHDN
V
CC
FB
AMP
BOOST
COMP
gm
I
I
I
I
R1
R
SENSE
I
COMP
Q4
Q3
Q2
Q1
Q5
V
SW
D1
V
IN
5
3
2
1
6
4
8
7
OPERATIOU
The LT1676 is a current mode switching regulator IC that
has been optimized for high efficiency operation in high
input voltage, low output voltage Buck topologies. The
Block Diagram shows an overall view of the system.
Several of the blocks are straightforward and similar to
those found in traditional designs, including: Internal Bias
Regulator, Oscillator and Feedback Amplifier. The novel
portion includes an elaborate Output Switch section and
Logic Section to provide the control signals required by
the switch section.
The LT1676 operates much the same as traditional
current mode switchers, the major difference being its
specialized output switch section. Due to space con-
straints, this discussion will not reiterate the basics of
current mode switcher/controllers and the “Buck” topol-
ogy. A good source of information on these topics is
Application Note 19.
Output Switch Theory
One of the classic problems in delivering low output
voltage from high input voltage at good efficiency is that
minimizing AC switching losses requires very fast volt-
age (dV/dt) and current (dI/dt) transition at the output
device. This is in spite of the fact that in a bipolar
implementation, slow lateral PNPs must be included in
the switching signal path.
Fast positive-going slew rate action is provided by lateral
PNP Q3 driving the Darlington arrangement of Q1 and Q2.
The extra
β
available from Q2 greatly reduces the drive
requirements of Q3.
Although desirable for dynamic reasons, this topology
alone will yield a large DC forward voltage drop. A second
lateral PNP, Q4, acts directly on the base of Q1 to reduce
the voltage drop after the slewing phase has taken place.
To achieve the desired high slew rate, PNPs Q3 and Q4 are
“force-fed” packets of charge via the current sources
controlled by the boost signal.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1676C | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Wide Input Range, High Efficiency, Step-Down Switching Regulator |
| LT1676CN8 | 功能描述:IC REG BUCK ADJ 0.7A 8DIP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
| LT1676CN8#PBF | 功能描述:IC REG BUCK ADJ 0.7A 8DIP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
| LT1676CS8 | 功能描述:IC REG BUCK ADJ 0.7A 8SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:升壓（升壓） 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式，混合 頻率 - 開關(guān):600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:8-SOIC |
| LT1676CS8#PBF | 功能描述:IC REG BUCK ADJ 0.7A 8SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:250 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
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