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參數(shù)資料
| 型號： | MAX5913AEMH+ |
| 廠商： | Maxim Integrated |
| 文件頁數(shù)： | 11/20頁 |
| 文件大小： | 614K |
| 描述： | IC HOT SWAP CTLR QUAD 48V 44MQFP |
| 產品培訓模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標準包裝： | 96 |
| 類型： | 熱交換控制器 |
| 應用： | IP 電話，LAN 網絡供電，網絡路由器和交換機 |
| 內部開關： | 無 |
| 電源電壓： | 35 V ~ 72 V |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 44-QFP |
| 供應商設備封裝： | 44-MQFP（10x10） |
| 包裝： | 托盤 |
+48V Quad Hot-Swap Controllers For
Power-Over-LAN
______________________________________________________________________________________ 11
Detailed Description
The MAX5913A/MAX5914A quadruple hot-swap con-
trollers provide Power-Over-MDI, also known as Power-
Over-LAN systems (Figure 5). The MAX5913A/
MAX5914A enable control of four external n-channel
MOSFET switches from a single V
CC
ranging from
+35V to +72V, with timing control and current-limiting
functions built in.
The MAX5913A/MAX5914A features include undervolt-
age lockout (UVLO), 100mA relay drivers, dual-level cur-
rent sense, foldback current limit, programmable
overcurrent time and auto-retry periods, internal charge
pumps to drive external MOSFET and soft-start, port sta-
tus output indicating power-OK (POK) or open-circuit
conditions (Figure 6).
Switch and Relay Control Inputs
The MAX5913A/MAX5914A ON_ inputs turn on the corre-
sponding MOSFET switch. Driving ON_ high turns on the
switch if the corresponding RLYON is driven high, and
V
CC
> V
UVLO
for more than 25.6ms. Driving RLYON_
high immediately turns on the corresponding relay, and
activates the 25.6ms delay after which the corresponding
ON_ input is active. Driving RLYON_ low immediately
turns off the switch and activates a 3.2ms delay, after
which the relay is turned off. These internal delays safely
allow driving ON_ and RLYON_ simultaneously. The relay
is turned on while the switch is off so that there is no volt-
age across the relay contacts. The relay is turned off
while the switch is off so that there is no current flowing
when the relay contacts are opened (see Figure 3).
Input Voltage and UVLO
The MAX5913A/MAX5914A operate from a +35V to +72V
supply voltage. V
CC
powers the MAX5913A/MAX5914A
analog circuitry and is monitored continuously during
startup and normal operation. The MAX5913A/MAX5914A
keep all MOSFET switches and relay drivers securely off
before V
CC
rises above V
UVLO
. The MAX5913A/
MAX5914A turn off all MOSFET switches and relay drivers
after V
CC
falls below V
UVLO
- V
UVLO,H
.
Startup
When the turn-on condition is met (see the Input
Voltage and UVLO and Switch and Relay Control Inputs
sections), the MAX5913A/MAX5914A slowly turn on the
external MOSFET switch by charging its gate using a
constant current source, I
GATE
(10礎 typ). The gate
voltage slope is determined by the total gate capaci-
tance C
GATE
connected to this node. Since the output
voltage follows the gate voltage, thus the output rises
with a slope determined by:
If a capacitor load is connected to the output, the total
current through the FET is:
where C
L
is the load capacitance and I
L
is the current
required by any load connected to the output during
the startup phase.
If the current through the FET reaches the programmed
current-limit value:
the internal current-limit circuitry activates and regu-
lates this FET current to be a value, I
LIM
, that depends
on V
OUT
(I
FLBK
) (Figure 8). See the Current Sensing
and Regulation section. In this case, the maximum rate
of change of the output is determined by:
The formula shows the necessity for I
LIM
to be larger
than I
L
in order to allow the output voltage to rise. The
foldback function is active as long as the circuit is in
overcurrent condition. Should the overcurrent condition
persist for a period longer than the maximum time t
O
,
the switch is latched off and GATE_ is discharged to
ground with a 1mA pulldown current.
If auto-retry is enabled, the switch turns on again after a
waiting period, t
OFF
, which is determined by the pro-
grammed duty cycle.
After the startup, the internal charge pumps provide
(V
CC
+ 9V) typical gate overdrive to fully turn on the
switch. When the switch is fully on (voltage drop across
the switch is d 1.5V), and the switch is not in current
limit, the POK signal is asserted.
Current Sensing and Regulation
The MAX5913A/MAX5914A control port current with
using two voltage comparators (dual-level detection)
that sense the voltage drop across an external current-
sense resistor. Connect CSP_ to V
CC
and connect a
current-sense resistor between CSP_ and DRAIN_.
Kelvin sensing should be used as shown in Figure 7.
V
t
I
I
C
OUT
LIM L
L
=
I
V
R
MAX
SC
SENSE
=
I I
C
C
I
GATE
L
GATE
L
=
+
V
t
I
C
OUT
GATE
GATE
=
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MAX5913AEMH+ | 功能描述:熱插拔功率分布 48V Hot-Swap Controller 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 |
| MAX5913AEMH+D | 制造商:Maxim Integrated Products 功能描述:HOT SWAP CNTRLR 44MQFP - Rail/Tube |
| MAX5913AEMH+T | 功能描述:熱插拔功率分布 48V Hot-Swap Controller 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 |
| MAX5913AEMH+TD | 制造商:Maxim Integrated Products 功能描述:HOT SWAP CNTRLR 44MQFP - Tape and Reel |
| MAX5913AEMH-T | 功能描述:熱插拔功率分布 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 |
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