參數(shù)資料
型號(hào)： MIC2594-2BM
廠商： MICREL INC
元件分類： 電源管理
英文描述： Replaced by PTH05060W :
中文描述： 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8
封裝： SOIC-8
文件頁數(shù)： 10/14頁
文件大小： 83K
代理商： MIC2594-2BM
MIC2588/MIC2594
Functional Description
Hot Swap Insertion
When circuit boards are inserted into systems carrying live
supply voltages (
“
hot swapped
”
), high inrush currents often
result due to the charging of bulk capacitance that resides
across the circuit board
’
s supply pins. These current spikes
can cause the system
’
s supply voltages to temporarily go out
of regulation, causing data loss or system lock-up. In more
extreme cases, the transients occurring during a hot swap
event may cause permanent damage to connectors or on-
board components.
The MIC2588 and the MIC2594 are designed to address
these issues by limiting the magnitude of the transient current
during hot swap events. This is achieved by controlling the
rate at which power is applied to the circuit board (di/dt and
dv/dt management). In addition, to inrush current control, the
MIC2588 and the MIC2594 incorporate input voltage super-
visory functions and current limiting, thereby providing robust
protection for both the system and the circuit board.
Start-Up Cycle
When the input voltage to the IC is between the overvoltage
and undervoltage thresholds (MIC2588) or is greater than
V
ON
(MIC2594), a start cycle is initiated. At this time, the
GATE pin of the IC applies a constant charging current
(I
GATEON
) to the gate of the external MOSFET (M1). C
FDBK
creates a Miller integrator out of the MOSFET circuit, which
limits the slew-rate of the voltage at the drain of M1. The drain
voltage rate-of-change (dv/dt) of M1 is:
Micrel
M9999-122303
10
December 2003
dv M1
dt
I
C
–
I
C
DRAIN
GATE(
–
)
FDBK
GATEON
FDBK
)
=
=
where I
GATE(+)
= Gate Charging Current = I
GATEON
;
I
GATE(
–
)
–
I
GATE(+)
, due to the extremely high
transconductance values of power MOSFETs; and
I
C
dv M1
dt
GATE(
–
)
FDBK
DRAIN
=
×
)
Relating the above to the maximum transient current into the
load capacitance to be charged upon hot swap or power-up
involves a simple extension of the same formula:
I
C
dv M1
dt
I
C
–
I
C
| I
|
C
I
C
CHARGE
LOAD
DRAIN
CHARGE
LOAD
GATEON
FDBK
CHARGE
LOAD
GATEON
FDBK
=
×
)
=
×
=
×
Transposing:
C
C
I
| I
|
FDBK
LOAD
GATEON
CHARGE
=
×
(1)
C
GATE
and R
FDBK
prevent turn-on and hot swap current
surges which would otherwise be caused by (C
FDBK
+
C
D-G(M1)
) coupling turn-on transients from the drain to the
gate of M1. An appropriate value for C
GATE
may be deter-
mined using the formula for a capacitive voltage divider:
Maximum voltage on C
GATE
at turn-on must be less than
V
THRESHOLD
of M1:
1. For a standard 10V enhancement N-Channel
MOSFET, V
THRESHOLD
is about 4.25V.
2. Choose 3.5V as a safe maximum voltage to safely
avoid turn-on transients.
V
G-S(M1)
×
[C
GATE
+ (C
FDBK
+ C
D-G(M1)
)]
= [(V
DD
–
V
EE
(min))
×
(C
FDBK
+ C
D-G(M1)
)]
V
G-S(M1)
×
C
GATE
= [(V
DD
–
V
EE
(min))
–
V
G-S(M1)
]
×
(C
FDBK
+ C
D-G(M1)
)
)
×
(
C
C
C
V
–
V
(min)
–
V
V
GATE
FDBK
D G(Q1)
DD
EE
G-S(M1)
G-S(M1)
=
+
(
)
(2)
While the value for R
FDBK
is not critical, it should be chosen
to allow a maximum of several milliamperes to flow in the
gate-drain circuit of M1 during turn-on. While the final value
for R
FDBK
is determined empirically, initial values between
R
FDBK
= 15k
to 27k
for systems with a maximum value of
75V for (V
DD
–
V
EE
(min)) are appropriate.
Resistor R4, in series with the MOSFETs gate, minimizes the
potential for parasitic high frequency oscillations from occur-
ring in M1. While the exact value of R4 is not critical,
commonly used values for R4 range from 10
to 33
.
For example, let us assume a hot swap controller is required
to maintain the inrush current into a 150
μ
F load capacitance
at 1.7A maximum, and that this circuit may operate from
supply voltages as high as (V
DD
–
V
EE
) = 75V. The MOSFET
to be used with the MIC2588/94 is an IRF540NS 100V
D
2
PAK device which has a typical (C
D-G
) of 250pF.
Calculating a value for C
FBDK
using Equation 1 yields:
150 F
45 A
1.7A
Good engineering practice suggests the use of the worst-
case parameter values for I
GATEON
from the
“
DC Electrical
Characteristics
”
section:
C
3.97nF
FDBK
=
=
C
150 F
60 A
1.7A
5.3nF
FDBK
=
=
where the nearest standard 5% value is 5.6nF. Substituting
5.6nF into Equation 2 from above yields:
C
5.6nF
250pF
75V
–
3.5V
3.5V
0.12 F
GATE
=
+
(
)
×
(
)
=
Finally, choosing R4 = 10
and R
FDBK
= 20k
will yield a
suitable, initial design for prototyping.
相關(guān)PDF資料
PDF描述
MIC2595R-2BM SINGLE-CHANNEL NEGATIVE HIGH VOLTAGE HOT SWAP POWER CONTROLLERS/SEQUENCERS
MIC2595R-1BM SINGLE-CHANNEL NEGATIVE HIGH VOLTAGE HOT SWAP POWER CONTROLLERS/SEQUENCERS
MIC2589 Replaced by PTH05060W :
MIC2589-1BM Replaced by PTH05060W :
MIC2589-2BM Replaced by PTH05060W :
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MIC2594-2BM TR 功能描述:IC CTRLR HOT SWAP NEG HV 8-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:100 系列:- 類型:熱插拔開關(guān) 應(yīng)用:通用 內(nèi)部開關(guān):是 電流限制:可調(diào) 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(yīng)商設(shè)備封裝:10-TDFN-EP（3x3） 包裝:管件
MIC2594-2YM 功能描述:熱插拔功率分布 Negative Voltage Hot-Swap Controller - Lead Free 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
MIC2594-2YM TR 功能描述:熱插拔功率分布 Negative Voltage Hot-Swap Controller - Lead Free 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
MIC2594-2YM-TR 功能描述:Hot Swap Controller 1 Channel -48V 8-SOIC 制造商:microchip technology 系列:- 包裝:剪切帶（CT） 零件狀態(tài):停產(chǎn) 類型:熱交換控制器 通道數(shù):1 內(nèi)部開關(guān):無 應(yīng)用:-48V 特性:故障超時(shí)，閉鎖故障 可編程特性:限流，壓擺率，UVLO 電壓 - 電源:-80 V ~ -19 V 電流 - 輸出（最大值）:- 工作溫度:-40°C ~ 85°C 電流 - 電源:3mA 安裝類型:表面貼裝 封裝/外殼:8-SOIC（0.154"，3.90mm 寬） 供應(yīng)商器件封裝:8-SOIC 功能引腳:DRAIN，OFF，ON，/PWRGD 標(biāo)準(zhǔn)包裝:1
MIC2595-1BM 功能描述:IC CTRLR HOT SWAP NEG HV 14-SOIC RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:100 系列:- 類型:熱插拔開關(guān) 應(yīng)用:通用 內(nèi)部開關(guān):是 電流限制:可調(diào) 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(yīng)商設(shè)備封裝:10-TDFN-EP（3x3） 包裝:管件
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