參數(shù)資料
型號(hào)： LM2575
廠商： ON SEMICONDUCTOR
英文描述： 1.0 A, Adjustable Output Voltage, Step-Down Switching Regulator(1.0A,可調(diào)輸出電壓,降壓型開(kāi)關(guān)穩(wěn)壓器)
中文描述： 1.0甲，可調(diào)輸出電壓，降壓型開(kāi)關(guān)穩(wěn)壓器（1.0安培，可調(diào)輸出電壓，降壓型開(kāi)關(guān)穩(wěn)壓器）
文件頁(yè)數(shù)： 19/28頁(yè)
文件大小： 363K
代理商： LM2575
LM2575
http://onsemi.com
19
Using a delayed startup arrangement, the input capacitor
can charge up to a higher voltage before the switchmode
regulator begins to operate.
The high input current needed for startup is now partially
supplied by the input capacitor C
in
.
Design Recommendations:
The inverting regulator operates in a different manner
than the buck converter and so a different design procedure
has to be used to select the inductor L1 or the output
capacitor C
out
.
The output capacitor values must be larger than is
normally required for buck converter designs. Low input
voltages or high output currents require a large value output
capacitor (in the range of thousands of F).
The recommended range of inductor values for the
inverting converter design is between 68 H and 220 H. To
select an inductor with an appropriate current rating, the
inductor peak current has to be calculated.
The following formula is used to obtain the peak inductor
current:
where ton
|VO|
Vin
|VO|x
1
fosc
, and fosc
52 kHz.
Ipeak
ILoad(Vin
|VO|)
Vin
Vinx ton
2L1
Under normal continuous inductor current operating
conditions, the worst case occurs when V
in
is minimal.
Note that the voltage appearing across the regulator is the
absolute sum of the input and output voltage, and must not
exceed 40 V.
Figure 26. Inverting BuckBoost
Regulator with Delayed Startup
D1
1N5819
L1
100 H
Output
2
4
Feedback
Unregulated
DC Input
12 V to 25 V
C
in
100 F
/50 V
1
3
5
ON/OFF
GND
+V
in
Regulated
Output
12 V @ 0.35 A
C
out
1800 F
/16 V
LM257512
C1
0.1 F
R1
47 k
R2
47 k
It has been already mentioned above, that in some
situations, the delayed startup or the undervoltage lockout
features could be very useful. A delayed startup circuit
applied to a buckboost converter is shown in Figure 26
.
Figure 32 in the “Undervoltage Lockout” section describes
an undervoltage lockout feature for the same converter
topology.
Figure 27. Inverting BuckBoost Regulator Shut Down
Circuit Using an Optocoupler
LM2575XX
1
3
5
GND
ON/OFF
+V
in
R2
47 k
C
in
100 F
NOTE: This picture does not show the complete circuit.
R1
47 k
R3
470
Shutdown
Input
MOC8101
V
out
Off
On
5.0 V
0
+V
in
With the inverting configuration, the use of the ON/OFF
pin requires some level shifting techniques. This is caused
by the fact, that the ground pin of the converter IC is no
longer at ground. Now, the ON/OFF pin threshold voltage
(1.4 V approximately) has to be related to the negative
output voltage level. There are many different possible shut
down methods, two of them are shown in Figures 27
and
28.
Figure 28. Inverting BuckBoost Regulator Shut Down
Circuit Using a PNP Transistor
NOTE: This picture does not show the complete circuit.
R2
5.6 k
Q1
2N3906
LM2575XX
1
3
5
GND
ON/OFF
R1
12 k
V
out
+V
in
Shutdown
Input
Off
On
+V
0
+V
in
C
in
100 F
Negative Boost Regulator
This example is a variation of the buckboost topology
and is called a negative boost regulator. This regulator
experiences relatively high switch current, especially at low
input voltages. The internal switch current limiting results in
lower output load current capability.
The circuit in Figure 29 shows the negative boost
configuration. The input voltage in this application ranges
from 5.0 V to 12 V and provides a regulated 12 V output.
相關(guān)PDF資料
PDF描述
LM2576D2T-12 EASY SWITCHER 3.0 A STEP.DOWN VOLTAGE REGULATOR
LM2576D2T-12 EASY SWITCHERE⑩ 3.0 A STEP-DOWN VOLTAGE REGULATOR
LM2576R 3.0A, 15V, Step-Down Switching Regulator
LM2577S-12 Pressure Transducer, Series 19 mm, Uncompensated, Pressure Range: 0 psi to 100 psi, Absolute, flush mount, 10 Vdc excitation
LM2577N-ADJ Pressure Transducer, Series 19 mm, Compensated, Pressure Range: 0 psi to 200 psi, Absolute, flush mount with flange, 10 Vdc excitation
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM2575/D 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Easy Switcher? 1.0 A Step-Down Voltage Regulator
LM2575_05 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:1.0 A, Adjustable Output Voltage, Step−Down Switching Regulator
LM2575_06 制造商:TI 制造商全稱:Texas Instruments 功能描述:1-A SIMPLE STEP-DOWN SWITCHING VOLTAGE REGULATOR
LM2575_09 制造商:MICREL 制造商全稱:Micrel Semiconductor 功能描述:52kHz Simple 1A Buck Regulator
LM2575-05IKC 制造商:TI 制造商全稱:Texas Instruments 功能描述:1-A SIMPLE STEP DOWN SWITCHING VOLTAGE REGULATOR
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*