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參數(shù)資料
| 型號： | MAX5921AESA |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 電源管理 |
| 英文描述： | Quadruple 2-Line To 1-Line Data Selectors/Multiplexers 20-LCCC -55 to 125 |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| 封裝： | 0.150 INCH, MS-012AA, SOIC-8 |
| 文件頁數(shù)： | 9/18頁 |
| 文件大?。?/td> | 313K |
| 代理商： | MAX5921AESA |
M
-48V Hot-Swap Controllers with External
R
SENSE
and High Gate Pulldown Current
_______________________________________________________________________________________
9
Board Insertion
Figure 6a shows a typical hot-swap circuit for -48V sys-
tems. When the circuit board first makes contact with
the backplane, the DRAIN to GATE capacitance (C
gd
)
of Q1 pulls up the GATE voltage to roughly IV
EE
x
(C
gd
/C
gd
+ C
gs
)I. The MAX5921/MAX5939 feature an
internal dynamic clamp between GATE and V
EE
to
keep the gate-to-source voltage of Q1 low during hot
insertion preventing Q1 from passing an uncontrolled
current to the load. For most applications, the internal
clamp between GATE and V
EE
of the MAX5921/
MAX5939 eliminates the need for an external gate-to-
source capacitor. The resistor R3 limits the current into
the clamp circuitry during card insertion.
Power-Supply Ramping
The MAX5921/MAX5939 can reside either on the back-
plane or the removable circuit board (Figure 6a). Power
is delivered to the load by placing an external N-chan-
nel MOSFET pass transistor in the power-supply path.
After the circuit board is inserted into the backplane,
and the supply voltage at V
EE
is stable and within the
undervoltage and overvoltage tolerance, the
MAX5921/MAX5939 gradually turn on the external
MOSFET by charging the gate of Q1 with a 45μA cur-
rent source. Capacitor C2 provides a feedback signal
to accurately limit the inrush current.
The inrush current can be calculated:
I
INRUSH
= I
PU
x C
L
/ C2
where C
L
is the total load capacitance, C3 + C4, and
I
PU
is the gate pullup current.
Figure 6b shows the inrush current waveform. The cur-
rent through C2 controls the GATE voltage. At the end
of the DRAIN ramp, the GATE voltage is charged to its
final value. The GATE-to-SENSE clamp limits the maxi-
mum
V
GATE
to 18V.
Board Removal
If the circuit card is removed from the backplane, the volt-
age at the UV falls below the UVLO detect threshold, and
the MAX5921/MAX5939 turn off the external MOSFET.
Current Limit and Electronic Circuit
Breaker
The MAX5921/MAX5939 provide current-limiting and cir-
cuit-breaker features that protect against excessive load
current and short-circuit conditions. The load current is
monitored by sensing the voltage across an external
sense resistor connected between V
EE
and SENSE.
MAX5921
MAX5939
V
EE
OV
UV
SENSE
GATE
DRAIN
PWRGD
V
DD
-48V RTN
-48V RTN
SHORT PIN
V
IN
+
V
IN
-
VICOR
VI-J3D-CY
-48V
GATE IN
C4
100
μ
F
100V
C3
0.1
μ
F
100V
C2
15nF
100V
R3
1k
5%
R2
10
5%
Q1
IRF530
R1
0.02
5%
R4
549k
1%
R5
6.49k
1%
R6
10k
1%
4.7nF
Figure 6a. Inrush Control Circuitry/Typical Application Circuit
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX5921BESA | Quadruple 2-Line To 1-Line Data Selectors/Multiplexers 16-CDIP -55 to 125 |
| MAX5921EESA | Quadruple 2-Line To 1-Line Data Selectors/Multiplexers 16-CFP -55 to 125 |
| MAX5939AESA | Quadruple 2-Input Positive-OR Gates 20-LCCC -55 to 125 |
| MAX5939EESA | Quadruple 2-Input Positive-OR Gates 14-CDIP -55 to 125 |
| MAX5939BESA | -48V Hot-Swap Controllers with External RSENSE and High Gate Pulldown Current |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX5921AESA+ | 功能描述:熱插拔功率分布 48V- Hot-Swap Controller RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| MAX5921AESA+T | 功能描述:熱插拔功率分布 48V- Hot-Swap Controller RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| MAX5921AESA-T | 功能描述:熱插拔功率分布 RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| MAX5921AEVKIT | 功能描述:熱插拔功率分布 Evaluation Kit for the MAX5920 MAX5921 MAX5939 RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
| MAX5921BESA | 功能描述:熱插拔功率分布 RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube |
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