參數資料
型號: MIC2580A
廠商: Micrel Semiconductor,Inc.
元件分類: 基準電壓源/電流源
英文描述: Hot-Swap PCI Power Controller
中文描述: 熱插拔PCI電源控制器
文件頁數: 19/21頁
文件大小: 252K
代理商: MIC2580A
February 2005
19
MIC2580A
MIC2580A
Application Information
Whenever voltage is applied to a highly capacitive load, high
inrush currents may result in voltage droop that may bring the
supply voltage out of regulation for the duration of the
transient. The MIC2580A solves this problem by specifically
controlling the current and voltage supply ramps so that the
system supply voltages are not disturbed. Very large capaci-
tive loads are easily supported with this device.
Figure 1 shows the timing during turn-on. When /ON is forced
low, all supplies are turned on at a slew rate determined by the
external capacitor, C
SLEW
.
Figure 2 shows the foldback characteristics for the supply
voltages. This foldback affect bounds the magnitude of the
current step when the supplies are turned on or shorted. This
specifies the compact PCI specification of 1.5A/ms, thereby
ensuring reliable operation. In discrete FET implementa-
tions, this magnitude can exceed several amps and may
cause the main supply to go out of regulation during this
transient event. This, in turn, could cause the system to
behave unpredictably. In addition, should a fault occur, the
MIC2580A will prevent system malfunctions by limiting the
current to within specifications.
MOSFET Selection
The external MOSFET should be selected to provide low
enough dc loss to satisfy the application’s voltage regulation
requirements. Note that the voltage across the sense resistor
Micrel, Inc.
must also be added to the dc voltage drop across the
MOSFET to compute total loss. In addition to meeting the
voltage regulation specifications, thermal specifications must
also be considered. During normal operation very little power
should be dissipated in the MOSFET. DC power dissipation
of the MOSFET is easily computed as
I
2
R
where
I
is the
drain current and
R
is the specified on-resistance of the
MOSFET at the expected operating drain current. However,
during excessive drain current or short-circuit faults, the
power dissipation in the external MOSFET will increase
dramatically. To help compute the effective power dissipated
during such transients, MOSFET manufacturers provide
transient thermal impedance curves for each MOSFET.
These curves provide the effective thermal impedance of the
MOSFET under pulsed or repetitive conditions; for example,
as will be the case when enabling into a short circuit fault.
From these curves the effective rise in junction temperature
of the MOSFET for a given condition can be computed. The
equation is given as:
peak
T
J
=
PDM
Z
θ
JA
+
T
A
where
PDM
is the power dissipated in the MOSFET usually
computed as
V
x
I
and
Z
θ
is the thermal response
factor provided from the curves. Since the MIC2580A re-
duces the current to 30% of full scale even under severe faults
such as short-circuits the MOSFET power dissipation is held
to safe levels. This feature allows MOSFETs with smaller
packages to be used for a given application thereby reducing
cost and PCB real-estate requirements.
12VOUT
5VSENSE
5VGATE
5VOUT
3VGATE
3VOUT
VPCHG
/POR
12VIN
/FAULT
CSTART
GND
/LPCIRST
5VIN
3VIN
/PCIRST
/ON
CSLEW
/EPWDGD
/PWDGD
M12VIN
MIC2580A
3VSENSE
CRST
IRF7413
IRF7413
3.3V
5V
12V
M12VOUT
+12V
+5V
+3.3V
GND
–12V
Power
/CIRST
BUS EN
–12V
/CIRST
D
/CIRST
–12V /100mA
12V/500mA
5V/5A
3.3V/7.6A
10m
10m
PCI Hot-Plug
Controller
Bus
Switch
D
GND
A
P
D0
D1
D2
D0
D1
D2
+5V
D
n
D
n
Figure 6. Hot-Plug PCI Application
相關PDF資料
PDF描述
MIC2580A-1.0BTS Hot-Swap PCI Power Controller
MIC2580A-1.6BTS Hot-Swap PCI Power Controller
MIC2580 Hot-Swap PCI Power Controller(熱交換PCI功率控制器)
MIC2588 Single-Channel, Negative High-Voltage Hot Swap Power Controllers
MIC2588-1BM Single-Channel, Negative High-Voltage Hot Swap Power Controllers
相關代理商/技術參數
參數描述
MIC2580A-1.0BTS 功能描述:IC CTRLR HOTSWAP PCI PWR 24TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產品培訓模塊:Obsolescence Mitigation Program 標準包裝:100 系列:- 類型:熱插拔開關 應用:通用 內部開關:是 電流限制:可調 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應商設備封裝:10-TDFN-EP(3x3) 包裝:管件
MIC2580A-1.0BTS TR 功能描述:IC CTRLR PCI HOT SWAP 24-TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產品培訓模塊:Obsolescence Mitigation Program 標準包裝:100 系列:- 類型:熱插拔開關 應用:通用 內部開關:是 電流限制:可調 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應商設備封裝:10-TDFN-EP(3x3) 包裝:管件
MIC2580A-1.0YTS 功能描述:熱插拔功率分布 PCI Hot Swap Controller - Lead Free RoHS:否 制造商:Texas Instruments 產品: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: 安裝風格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube
MIC2580A-1.0YTS TR 功能描述:熱插拔功率分布 PCI Hot Swap Controller - Lead Free RoHS:否 制造商:Texas Instruments 產品: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: 安裝風格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube
MIC2580A-1.6BTS 功能描述:IC CTRLR PCI HOT SWAP 24-TSSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產品培訓模塊:Obsolescence Mitigation Program 標準包裝:100 系列:- 類型:熱插拔開關 應用:通用 內部開關:是 電流限制:可調 電源電壓:9 V ~ 13.2 V 工作溫度:-40°C ~ 150°C 安裝類型:表面貼裝 封裝/外殼:10-WFDFN 裸露焊盤 供應商設備封裝:10-TDFN-EP(3x3) 包裝:管件