- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377711 > LTC4211 (Linear Technology Corporation) Negative 48V Hot Swap Controller PDF資料下載
參數(shù)資料
| 型號： | LTC4211 |
| 廠商： | Linear Technology Corporation |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Negative 48V Hot Swap Controller |
| 中文描述： | 負48V熱插拔控制器 |
| 文件頁數(shù)： | 8/12頁 |
| 文件大小： | 230K |
| 代理商： | LTC4211 |
8
LT4250L/LT4250H
4250lhf
APPLICATIO
S I
N
FOR
ATIO
U
Current Limit/Electronic Circuit Breaker
The LT4250 features a current limit function that protects
against short circuits or excessive supply currents. If the
current limit is active for more than 500
μ
s the electronic
circuit breaker will trip. By placing a sense resistor
between the V
EE
and SENSE pin, the current limit will be
activated whenever the voltage across the sense resistor
is greater than 50mV.
Note that the current limit threshold should be set suffi-
ciently high to account for the sum of the load current and
the inrush current. The maximum value of the inrush
current is given by:
W
U
I
mV
R
I
INRUSH
SENSE
LOAD
≤
0.
40
–
,
where the 0.8 factor is used as a worst case margin
combined with the minimum trip voltage (40mV).
In the case of a short circuit, the current limit circuitry
activates and immediately pulls the GATE low, servos the
SENSE voltage to 50mV, and starts a 500
μ
s timer. The
MOSFET current is limited to 50mV/R
SENSE
(see Figure 7).
If the short circuit persists for more than 500
μ
s, the circuit
breaker trips and pulls the GATE pin low, shutting off the
MOSFET. The circuit breaker is reset by pulling UV low, or
by cycling power to the part. If the short circuit clears
before the 500
μ
s timing interval the current limit will
deactivate and release the GATE.
Figure 7. Short-Circuit Protection Waveforms
The LT4250 guards against voltage steps on the input
supply. A positive voltage step (increasing in magnitude)
on the input supply causes an inrush current that is
proportional to the voltage slew rate I = C
L
V/
T. If the
inrush exceeds 50mV/R
SENSE
, the current limit will acti-
vate as shown in Figure 8. The GATE pin pulls low, limiting
the current to 50mV/R
SENSE
. At this level the MOSFET
drain will not follow the source as the input voltage rapidly
changes, but instead remains at the voltage stored on the
load capacitance. The load capacitance begins to charge
at a current of 50mV/R
SENSE
, but not for long. As the load
capacitance charges, C2 pushes back on the gate and
limits the MOSFET current in a manner identical to the
initial start-up condition which is less than the short circuit
limiting value of 50mV/R
SENSE
. Thus the circuit breaker
does not trip. To ensure correct operation under input
voltage step conditions, R
SENSE
must be chosen to pro-
vide a current limit value greater than the sum of the load
current and the dynamic current in the load capacitance.
For C2 values less than 10nF a positive voltage step on the
input supply can result in the Q1 turning off momentarily
which can shut down the output. By adding an additional
resistor and diode, Q1 remains on during the voltage step.
This is shown as D1 and R7 in Figure 9. The purpose of D1
is to shunt current around R7 when the power pins first
make contact and allow C1 to hold the GATE low. The value
of R7 should be sized to generate an R7 C1 time constant
of 33
μ
s.
Under some conditions, a short circuit at the output can
cause the input supply to dip below the UV threshold. The
LT4250 turns off once and then turns on until the elec-
tronic circuit breaker is tripped. This can be minimized by
adding a deglitching delay to the UV pin with a capacitor
from UV to V
EE
. This capacitor forms an RC time constant
with the resistors at UV, allowing the input supply to
recover before the UV pin resets the circuit breaker.
DRAIN
50V/DIV
GATE
10V/DIV
I
D
(Q1)
5A/DIV
1ms/DIV
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC4251 | Negative 48V Hot Swap Controller |
| LTC4211CMS | Hot Swap Controller with Multifunction Current Control |
| LTC4211CMS8 | Hot Swap Controller with Multifunction Current Control |
| LTC4211CS8 | Hot Swap Controller with Multifunction Current Control |
| LTC4211IMS | Hot Swap Controller with Multifunction Current Control |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC4211_12 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:Hot Swap Controller |
| LTC4211CMS | 功能描述:IC CONTROLLER HOT SWAP 10-MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 標準包裝:50 系列:- 類型:熱交換控制器 應(yīng)用:-48V 遠程電力系統(tǒng)，AdvancedTCA ? 系統(tǒng)，高可用性 內(nèi)部開關(guān):無 電流限制:可調(diào) 電源電壓:11.5 V ~ 14.5 V 工作溫度:-40°C ~ 85°C 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-MSOP 包裝:管件 |
| LTC4211CMS#PBF | 功能描述:IC CONTROLLER HOT SWAP 10-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:119 系列:- 類型:熱交換控制器 應(yīng)用:通用型，PCI Express? 內(nèi)部開關(guān):無 電流限制:- 電源電壓:3.3V，12V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:80-TQFP 供應(yīng)商設(shè)備封裝:80-TQFP（12x12） 包裝:托盤 產(chǎn)品目錄頁面:1423 (CN2011-ZH PDF) |
| LTC4211-CMS#PBF | 制造商:LINEAR 功能描述: 制造商:Linear Technology 功能描述: |
| LTC4211CMS#TR | 功能描述:IC CONTROLLER HOT SWAP 10-MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 標準包裝:50 系列:- 類型:熱交換控制器 應(yīng)用:-48V 遠程電力系統(tǒng)，AdvancedTCA ? 系統(tǒng)，高可用性 內(nèi)部開關(guān):無 電流限制:可調(diào) 電源電壓:11.5 V ~ 14.5 V 工作溫度:-40°C ~ 85°C 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-MSOP 包裝:管件 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。