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參數(shù)資料
| 型號： | LM2591 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | SIMPLE SWITCHER Power Converter 150 kHz 1A Step-Down Voltage Regulator |
| 中文描述： | SIMPLE SWITCHER系列電源轉(zhuǎn)換器150千赫1A步降穩(wěn)壓器 |
| 文件頁數(shù)： | 17/20頁 |
| 文件大?。?/td> | 730K |
| 代理商： | LM2591 |
Application Information
(Continued)
Because of differences in the operation of the inverting
regulator, the standard design procedure is not used to
select the inductor value. In the majority of designs, a 33 μH,
3A inductor is the best choice. Capacitor selection can also
be narrowed down to just a few values.
This type of inverting regulator can require relatively large
amounts of input current when starting up, even with light
loads. Input currents as high as the LM2591HV current limit
(approx 4A) are needed for at least 2 ms or more, until the
output reaches its nominal output voltage. The actual time
depends on the output voltage and the size of the output
capacitor. Input power sources that are current limited or
sources that can not deliver these currents without getting
loaded down, may not work correctly. Because of the rela-
tively high startup currents required by the inverting topology,
the delayed startup feature (C1, R
1
and R
2
) shown in
Figure
11
is recommended. By delaying the regulator startup, the
input capacitor is allowed to charge up to a higher voltage
before the switcher begins operating. A portion of the high
input current needed for startup is now supplied by the input
capacitor (C
IN
). For severe start up conditions, the input
capacitor can be made much larger than normal.
lNVERTING REGULATOR SHUTDOWN METHODS
To use the ON /OFF pin in a standard buck configuration is
simple, pull it below 1.3V (
@
25C, referenced to ground) to
turn regulator ON, pull it above 1.3V to shut the regulator
OFF. With the inverting configuration, some level shifting is
required, because the ground pin of the regulator is no
longer at ground, but is now setting at the negative output
voltage level. Two different shutdown methods for inverting
regulators are shown in
Figure 12
and
Figure 13
10129339
This circuit has hysteresis
Regulator starts switching at V
IN
= 13V
Regulator stops switching at V
IN
= 8V
FIGURE 10. Undervoltage Lockout with Hysteresis for Inverting Regulator
10129340
C
IN
—68 μF/25V Tant. Sprague 595D
470 μF/50V Elec. Panasonic HFQ
C
OUT
—47 μF/20V Tant. Sprague 595D
220 μF/25V Elec. Panasonic HFQ
FIGURE 11. Inverting 5V Regulator with Delayed Startup
L
www.national.com
17
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM2592HVS-3.3 | Aluminum Electrolytic Capacitor; Capacitor Type:General Purpose; Voltage Rating:100VDC; Capacitor Dielectric Material:Aluminum Electrolytic; Operating Temperature Range:-40 C to +85 C; Capacitance:1000uF RoHS Compliant: Yes |
| LM2592HVT-ADJ | SIMPLE SWITCHER Power Converter 150 kHz 2A Step-Down Voltage Regulator |
| LM2592HVT-5.0 | SIMPLE SWITCHER Power Converter 150 kHz 2A Step-Down Voltage Regulator |
| LM2592HVT-3.3 | Aluminum Electrolytic Capacitor; Capacitor Type:General Purpose; Voltage Rating:250VDC; Capacitor Dielectric Material:Aluminum Electrolytic; Operating Temperature Range:-40 C to +85 C; Capacitance:1000uF RoHS Compliant: Yes |
| LM2592HVS-ADJ | Aluminum Electrolytic Capacitor; Capacitor Type:General Purpose; Voltage Rating:200VDC; Capacitor Dielectric Material:Aluminum Electrolytic; Operating Temperature Range:-40 C to C; Capacitance:1000uF RoHS Compliant: Yes |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM2591HVS-3.3 | 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 安裝風格:SMD/SMT |
| LM2591HVS-3.3/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 安裝風格:SMD/SMT |
| LM2591HVS-5.0 | 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 安裝風格:SMD/SMT |
| LM2591HVS-5.0/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 PWR CONVERTER 150KHz 1A ST-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 安裝風格:SMD/SMT |
| LM2591HVS-5.0/NOPB | 制造商:Texas Instruments 功能描述:DC/DC Converter (DC-DC) / Switching Regu |
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