參數(shù)資料
型號: LM2596T-3.3
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 穩(wěn)壓器
英文描述: SIMPLE SWITCHER Power Converter 150 kHz 3A Step-Down Voltage Regulator
中文描述: 7.5 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, PZFM5
封裝: BENT STAGGERED, TO-220, 5 PIN
文件頁數(shù): 26/31頁
文件大?。?/td> 736K
代理商: LM2596T-3.3
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,
3.5Ainductor is the best choice. Capacitor selection can also
be narrowed down to just a few values. Using the values
shown in Figure 25will provide good results in the majority of
inverting designs.
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 LM2596 current limit
(approx 4.5A) 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
25 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
). For severe start up conditions, the input
capacitor can be made much larger than normal.
01258339
This circuit has hysteresis
Regulator starts switching at V
IN
= 13V
Regulator stops switching at V
IN
= 8V
FIGURE 24. Undervoltage Lockout with Hysteresis for Inverting Regulator
01258340
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 25. Inverting 5V Regulator with Delayed Startup
01258341
FIGURE 26. Inverting Regulator Typical Load Current
L
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26
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM2596T33 制造商:Texas Instruments 功能描述:SWITCHING REG 3A 3.3V 2596 TO-220
LM2596T-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(fēng)格:SMD/SMT
LM2596T-5.0 制造商:Texas Instruments 功能描述:SWITCHING REG 3A 5.0V 2596 TO-220
LM2596T-5.0/LB02 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
LM2596T-5.0/LB03 制造商:Texas Instruments 功能描述:Conv DC-DC Single Inv/Step Down 4.5V to 40V 5-Pin(5+Tab) TO-220 Rail