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参数资料
| 型号： | LTC4227IUFD-1#TRPBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | POWER SUPPLY MANAGEMENT CKT, PQCC20 |
| 封装： | 4 X 5 MM, PLASTIC, MO-220, QFN-20 |
| 文件页数： | 4/20页 |
| 文件大小： | 307K |
| 代理商： | LTC4227IUFD-1#TRPBF |
LTC4227-1/LTC4227-2
12
422712f
applicaTions inForMaTion
Board Presence Detect with EN
If ON is high when the EN pin goes low, indicating a board
presence, the LTC4227 initiates a 100ms timing cycle for
contact debounce. Upon board insertion, any bounces
on the EN pin restart the timing cycle. When the 100ms
timing cycle is done, the internal fault latches are cleared.
If the EN pin remains low at the end of the timing cycle,
HGATE is charged up with a 10A current source to turn
on the Hot Swap MOSFET.
If the EN pin goes high, indicating a board removal, the
HGATE pin is pulled low with a 300A current sink after
a 20s delay, turning off the Hot Swap MOSFET, without
clearing any latched faults.
Overcurrent Fault
The LTC4227 features an adjustable current limit with
circuitbreakerfunctionthatprotectstheexternalMOSFETs
againstshortcircuitsorexcessiveloadcurrent.Thevoltage
across the external sense resistor, RS, is monitored by an
electronic circuit breaker (ECB) and active current limit
(ACL) amplifier. The electronic circuit breaker will turn off
the Hot Swap MOSFET with a 200mA current from HGATE
to OUT if the voltage across the sense resistor exceeds
VSENSE(CB) (50mV) for longer than the fault filter delay
configured at the TMR pin.
Active current limiting begins when the sense voltage
exceeds the ACL threshold
VSENSE(ACL) (65mV), which
is 1.3
× the ECB threshold VSENSE(CB). The gate of the
Hot Swap MOSFET is brought under control by the ACL
amplifier and the output current is regulated to maintain
the ACL threshold across the sense resistor. At this point,
the fault filter starts the timeout with a 100A current
charging the TMR pin capacitor. If the TMR pin voltage
exceeds its threshold (1.235V), the external MOSFET
turns off with HGATE pulled to ground by 300A, and its
associated FAULT pulls low.
After the Hot Swap MOSFET turns off, the TMR pin ca-
pacitor is discharged with a 2A pull-down current until
its threshold reaches 0.2V. This is followed by a cool-off
period of 14 timing cycles at the TMR pin. For the latch-off
part (LTC4227-1), the HGATE pin voltage does not restart
at the end of the cool-off period, unless the latched fault
is cleared by pulling the ON pin low or toggling the EN
pin from high to low. For the auto-retry part (LTC4227-2),
the latched fault is cleared automatically at the end of the
cool-off period, and the HGATE pin restarts charging up
to turn on the MOSFET. Figure 4 shows an overcurrent
fault on the 12V output.
Intheeventofasevereshort-circuitfaultonthe12Voutput
as shown in Figure 5, the output current can surge to tens
of amperes. The LTC4227 responds within 1s to bring
the current under control by pulling the HGATE to OUT
voltage down to zero volts. Almost immediately, the gate
of the Hot Swap MOSFET recovers rapidly due to the RHG
and CHG network, and current is actively limited until the
electronic circuit breaker times out. Due to parasitic sup-
ply lead inductance, an input supply without any bypass
capacitor may collapse during the high current surge and
thenspikeupwardswhenthecurrentisinterrupted.Figure 9
shows the input supply transient suppressors consisting
of Z1, RSNUB1, CSNUB1 and Z2, RSNUB2, CSNUB2 for the two
supplies if there is no input capacitance.
Figure 4. Overcurrent Fault on 12V Output
Figure 5. Severe Short-Circuit on 12V Output
OUT
10V/DIV
HGATE
10V/DIV
ILOAD
20A/DIV
200s/DIV
422712 F04
OUT
10V/DIV
HGATE
10V/DIV
ILOAD
20A/DIV
2s/DIV
422712 F05
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4227IUFD-2#PBF | 功能描述:IC CONTROLLER HOT SWAP 20-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
| LTC4227IUFD-2#TRPBF | 功能描述:IC CTRLR HOT SWAP 20-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
| LTC4228-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Ideal Diode and Hot Swap Controller |
| LTC4228CGN-1#PBF | 功能描述:IC HOT SWAP CTRLR 28SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
| LTC4228CGN-1#TRPBF | 功能描述:IC HOT SWAP CTRLR 28SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 热交换 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:119 系列:- 类型:热交换控制器 应用:通用型，PCI Express? 内部开关:无 电流限制:- 电源电压:3.3V，12V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:80-TQFP 供应商设备封装:80-TQFP（12x12） 包装:托盘 产品目录页面:1423 (CN2011-ZH PDF) |
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