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參數(shù)資料
| 型號(hào)： | LM3100MH |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SIMPLE SWITCHER㈢ Synchronous 1MHz 1.5A Step-Down Voltage Regulator |
| 中文描述： | 1.9 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO20 |
| 封裝： | PLASTIC, TSSOP-20 |
| 文件頁數(shù)： | 11/15頁 |
| 文件大?。?/td> | 1073K |
| 代理商： | LM3100MH |
ON-Time Timer, Shutdown
(Continued)
(5)
The LM3100 can be remotely shut down by taking the EN pin
below 1.1V. Refer to Figure 1. In this mode the SS pin is
internally grounded, the on-timer is disabled, and bias cur-
rents are reduced. Releasing the EN pin allows normal
operation to resume. The voltage at the EN pin is between
1.5V and 3.0V, depending on V
IN
and the pull-up resistor.
Current Limit
Current limit detection occurs during the off-time by monitor-
ing the re-circulating current through the low-side synchro-
nous switch. Referring to Functional Block Diagram, when
the buck switch is turned off, inductor current flows through
the load, into PGND, and through the internal low-side syn-
chronous switch. If that current exceeds 1.9A the current
limit comparator toggles, forcing a delay to the start of the
next on-time period. The next cycle starts when the re-
circulating current falls back below 1.9A and the voltage at
FB is below 0.8V. The inductor current is monitored during
the low-side switch on-time. As long as the overload condi-
tion persists and the inductor current exceeds 1.9A, the
high-side switch will remain inhibited. The operating fre-
quency is lower during an over-current due to longer than
normal off-times.
Figure 2 illustrates the inductor current waveform. During
normal operation the load current is low, the average of the
ripple waveform. When an overload occurs the current ratch-
ets up until it exceeds 1.9A. During the Current Limited
portion of Figure 2, the current ramps down to 1.9A during
each off-time, initiating the next on-time (assuming the volt-
age at FB is
<
0.8V). During each on-time the current ramps
up an amount equal to:
(6)
During this time the LM3100 is in a constant current mode,
with an average load current (I
OCL
) equal to 1.9A +
I/2.
20174704
FIGURE 1. Shutdown Implementation
20174705
FIGURE 2. Inductor Current - Current Limit Operation
L
www.national.com
11
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM3100MH/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 SYNC 1MHZ 1.5A STEP- DOWN VLTG REG RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM3100MHX | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM3100MHX/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM3101 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Secondary-Side PWM Controller |
| LM3101M | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Secondary-Side PWM Controller |
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