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参数资料
| 型号： | LTC4253AIGN#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | -48V Hot Swap Controller with Sequencer; Package: SSOP; No of Pins: 16; Temperature Range: -40°C to +85°C |
| 中文描述： | 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO16 |
| 封装： | 0.150 INCH, LEAD FREE, PLASTIC, SSOP-16 |
| 文件页数： | 11/34页 |
| 文件大小： | 369K |
| 代理商： | LTC4253AIGN#PBF |
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LTC4253/LTC4253A
19
425353afd
applicaTions inForMaTion
TIMER commences charging CT (trace 4) while the analog
current limit loop maintains the fault current at 100mV/RS,
which in this case is 5A (trace 2). Note that the backplane
voltage (trace 1) sags under load. Timer pull-up is accel-
erated by VOUT. When CT reaches 4V, GATE turns off, the
PWRGD signals pull high, the load current drops to zero
and the backplane rings up to over 100V. The transient
associated with the GATE turn-off can be controlled with
a snubber to reduce ringing and a transient voltage sup-
pressor (such as Diodes Inc. SMAT70A) to clip off large
spikes. The choice of RC for the snubber is usually done
experimentally. The value of the snubber capacitor is usu-
ally chosen between 10 to 100 times the MOSFET COSS.
The value of the snubber resistor is typically between 3
to 100.
A low impedance short on one card may influence the
behavior of others sharing the same backplane. The ini-
tial glitch and backplane sag as seen in Figure 5 trace1,
can rob charge from output capacitors on the adjacent
card. When the faulty card shuts down, current flows in
to refresh the capacitors. If LTC4253/LTC4253A are used
by the other cards, they respond by limiting the inrush
current to a value of VACL/RS. If CT is sized correctly, the
capacitors will recharge long before CT times out.
Figure 5. Output Short-Circuit Behavior of LTC4253
Sense
The SENSE pin is monitored by the circuit breaker (CB)
comparator, the analog current limit (ACL) amplifier, and
the fast current limit (FCL) comparator. Each of these three
measures the potential of SENSE relative to VEE. When
SENSE exceeds 50mV, the CB comparator activates the
200ATIMERpull-up.At100mV(60mVfortheLTC4253A)
the ACL amplifier servos the MOSFET current, and at
200mV the FCL comparator abruptly pulls GATE low in
an attempt to bring the MOSFET current under control. If
any of these conditions persists long enough for TIMER to
charge CT to 4V (see Equation3), the LTC4253/LTC4253A
shut down and pull GATE low.
If the SENSE pin encounters a voltage greater than VACL,
theACLamplifierwillservoGATEdownwardsinanattempt
to control the MOSFET current. Since GATE overdrives the
MOSFETinnormaloperation,theACLamplifierneedstime
to discharge GATE to the threshold of the MOSFET. For a
mild overload the ACL amplifier can control the MOSFET
current, but in the event of a severe overload the current
may overshoot. At SENSE = 200mV the FCL comparator
takes over, quickly discharging the GATE pin to near VEE
potential. FCL then releases, and the ACL amplifier takes
over. All the while TIMER is running. The effect of FCL is
to add a nonlinear response to the control loop in favor
of reducing MOSFET current.
Owing to inductive effects in the system, FCL typically
overcorrectsthecurrentlimitloop,andGATEundershoots.
A zero in the loop (resistor RC in series with the gate
capacitor) helps the ACL amplifier to recover.
SHORT-CIRCUIT OPERATION
Circuit behavior arising from a load side low impedance
short is shown in Figure 5. Initially the current overshoots
the analog current limit level of VSENSE=200mV (trace 2)
as the GATE pin works to bring VGSundercontrol(trace3).
Theovershootglitchesthebackplaneinthenegativedirec-
tion and when the current is reduced to 100mV/RS, the
backplane responds by glitching in the positive direction.
GATE
0.5ms
10V
SENSE
0.5ms
200mV
–48RTN
0.5ms
50V
TIMER
0.5ms
5V
4253 F05
SUPPLY RING OWING
TO CURRENT OVERSHOOT
SUPPLY RING OWING
TO MOSFET TURN-OFF
ONSET OF OUTPUT
SHORT-CIRCUIT
FAST CURRENT
LIMIT
CTIMER RAMP
LATCH OFF
TRACE 1
TRACE 2
TRACE 3
TRACE 4
ANALOG
CURRENT LIMIT
相关PDF资料 |
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| LTC4253AIGN#TRPBF | -48V Hot Swap Controller with Sequencer; Package: SSOP; No of Pins: 16; Temperature Range: -40°C to +85°C |
| LTC4253CGN#PBF | -48V Hot Swap Controller with Sequencer; Package: SSOP; No of Pins: 16; Temperature Range: 0°C to +70°C |
| LTC4253CGN#TRPBF | -48V Hot Swap Controller with Sequencer; Package: SSOP; No of Pins: 16; Temperature Range: 0°C to +70°C |
| LTC4253IGN#PBF | -48V Hot Swap Controller with Sequencer; Package: SSOP; No of Pins: 16; Temperature Range: -40°C to +85°C |
| LTC4253IGN#TRPBF | -48V Hot Swap Controller with Sequencer; Package: SSOP; No of Pins: 16; Temperature Range: -40°C to +85°C |
相关代理商/技术参数 |
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| LTC4253BCGN#PBF | 功能描述:IC HOT SWAP CONTROLLER 16SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 标准包装:50 系列:- 类型:热交换控制器 应用:-48V 远程电力系统，AdvancedTCA ? 系统，高可用性 内部开关:无 电流限制:可调 电源电压:11.5 V ~ 14.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-MSOP 包装:管件 |
| LTC4253BCGN#PBF | 制造商:Linear Technology 功能描述:HOT SWAP CONTROLLER -48V SSOP-16 |
| LTC4253BCGN#TRPBF | 功能描述:IC HOT SWAP CONTROLLER 16SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:100 系列:- 类型:热插拔开关 应用:通用 内部开关:是 电流限制:可调 电源电压:9 V ~ 13.2 V 工作温度:-40°C ~ 150°C 安装类型:表面贴装 封装/外壳:10-WFDFN 裸露焊盘 供应商设备封装:10-TDFN-EP（3x3） 包装:管件 |
| LTC4253BIGN#PBF | 功能描述:IC HOT SWAP CONTROLLER 16SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 标准包装:50 系列:- 类型:热交换控制器 应用:-48V 远程电力系统，AdvancedTCA ? 系统，高可用性 内部开关:无 电流限制:可调 电源电压:11.5 V ~ 14.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-MSOP 包装:管件 |
| LTC4253BIGN#PBF | 制造商:Linear Technology 功能描述:HOT SWAP CONTROLLER -48V SSOP-16 |
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