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参数资料
| 型号： | LM3102TL-1 |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PBGA28 |
| 封装： | USMD-28 |
| 文件页数： | 4/20页 |
| 文件大小： | 623K |
| 代理商： | LM3102TL-1 |
(5)
The LM3102 can be remotely shutdown by pulling the voltage
of the EN pin below 1V. In this shutdown mode, the SS pin is
internally grounded, the on-timer is disabled, and bias cur-
rents are reduced. Releasing the EN pin allows normal oper-
ation to resume because the EN pin is internally pulled up.
30021325
FIGURE 1. Shutdown Implementation
Current Limit
Current limit detection is carried out during the off-time by
monitoring the re-circulating current through the synchronous
MOSFET. Referring to the Functional Block Diagram, when
the main MOSFET is turned off, the inductor current flows
through the load, the PGND pin and the internal synchronous
MOSFET. If this current exceeds 2.7A, the current limit com-
parator toggles, and as a result disabling the start of the next
on-time period. The next switching cycle starts when the re-
circulating current falls back below 2.7A (and the voltage at
the FB pin is below 0.8V). The inductor current is monitored
during the on-time of the synchronous MOSFET. As long as
the inductor current exceeds 2.7A, the main MOSFET will re-
main inhibited to achieve current limit. The operating frequen-
cy is lower during current limit due to a longer off-time.
Figure 2 illustrates an inductor current waveform. On aver-
age, the output current I
OUT is the same as the inductor
current I
L, which is the average of the rippled inductor current.
In case of current limit (the current limit portion of Figure 2),
the next on-time will not initiate until that the current drops
below 2.7A (assume the voltage at the FB pin is lower than
0.8V). During each on-time the current ramps up an amount
equal to:
(6)
During current limit, the LM3102 operates in a constant cur-
rent mode with an average output current I
OUT(CL) equal to
2.7A + I
LR / 2.
30021326
FIGURE 2. Inductor Current - Current Limit Operation
www.national.com
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LM3102
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM3102TL-1/NOPB | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM3102TLX-1/NOPB | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM3103 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:SIMPLE SWITCHER㈢ Synchronous 1MHz 0.75A Step-Down Voltage Regulator |
| LM3103EVAL | 功能描述:电源管理IC开发工具 LM3103 EVAL BOARD RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| LM3103EVAL/NOPB | 功能描述:电源管理IC开发工具 LM3103 EVAL BRD RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
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