參數(shù)資料
型號(hào): LM1575-5.0MW8
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 穩(wěn)壓器
英文描述: 3.2 A SWITCHING REGULATOR, 62 kHz SWITCHING FREQ-MAX, UUC
封裝: WAFER
文件頁數(shù): 11/40頁
文件大?。?/td> 917K
代理商: LM1575-5.0MW8
Additional Applications (Continued)
UNDERVOLTAGE LOCKOUT
In some applications it is desirable to keep the regulator off
until the input voltage reaches a certain threshold. An und-
ervoltage lockout circuit which accomplishes this task is
shown in
Figure 12, while Figure 13 shows the same circuit
applied to a buck-boost configuration. These circuits keep
the regulator off until the input voltage reaches a predeter-
mined level.
V
TH ≈ VZ1 +2VBE (Q1)
DELAYED STARTUP
The ON /OFF pin can be used to provide a delayed startup
feature as shown in
Figure 14. With an input voltage of 20V
and for the part values shown, the circuit provides approxi-
mately 10 ms of delay time before the circuit begins switch-
ing. Increasing the RC time constant can provide longer
delay times. But excessively large RC time constants can
cause problems with input voltages that are high in 60 Hz or
120 Hz ripple, by coupling the ripple into the ON /OFF pin.
ADJUSTABLE OUTPUT, LOW-RIPPLE
POWER SUPPLY
A 1A power supply that features an adjustable output voltage
is shown in
Figure 15. An additional L-C filter that reduces
the output ripple by a factor of 10 or more is included in this
circuit.
01147516
Typical Load Current
200 mA for VIN = 5.2V
500 mA for VIN = 7V
Note: Pin numbers are for TO-220 package.
FIGURE 11. Negative Boost
01147517
Note: Complete circuit not shown.
Note: Pin numbers are for the TO-220 package.
FIGURE 12. Undervoltage Lockout for Buck Circuit
01147518
Note: Complete circuit not shown (see
Note: Pin numbers are for the TO-220 package.
FIGURE 13. Undervoltage Lockout
for Buck-Boost Circuit
01147519
Note: Complete circuit not shown.
Note: Pin numbers are for the TO-220 package.
FIGURE 14. Delayed Startup
LM1575/LM2575/LM2575HV
www.national.com
19
相關(guān)PDF資料
PDF描述
LM1575WG5.0-MPR 3.2 A SWITCHING REGULATOR, 62 kHz SWITCHING FREQ-MAX, CDSO16
LM2575MX-15/NOPB 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PDSO24
LM2575BUT&R 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PSSO5
LM2575-5.0BUT&R 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PSSO5
LM2575-3.3WUTR 3.2 A SWITCHING REGULATOR, 63 kHz SWITCHING FREQ-MAX, PSSO5
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM1575AK 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller
LM1575HVK-12/883 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller
LM1575HVK12/883QF 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Texas Instruments 功能描述:
LM1575HVK-15/883 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller
LM1575HVK-3.3/883 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Mode SMPS Controller