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參數(shù)資料
| 型號： | LM5045MH |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING CONTROLLER, 540 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封裝： | ETSSOP-28 |
| 文件頁數(shù)： | 16/28頁 |
| 文件大小： | 610K |
| 代理商： | LM5045MH |
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The UVLO and OVP can also be set together using a 3 re-
sistor divider ladder as shown in Figure 15. R
1 is calculated
as explained in the basic UVLO divider selection. Using the
same values, as in the above two examples, for the UVLO
and OVP set points, R
1 and R3 remain the same at 100k
and 1.5k
. The R
2 is 2.7k obtained by subtracting R3 from
4.2k
.
Remote configuration of the controller’s operational modes
can be accomplished with open drain device(s) connected to
the UVLO pin as shown in Figure 16.
Figure 17 shows an application of the OVP comparator for
Remote Thermal Protection using a thermistor (or multiple
thermistors) which may be located near the main heat
sources of the power converter. The negative temperature
coefficient (NTC) thermistor is nearly logarithmic, and in this
example a 100k
thermistor with the β material constant of
4500 Kelvin changes to approximately 2k
at 130C. Setting
R
1 to one-third of this resistance (665) establishes 130C as
the desired trip point (for VREF = 5V). In a temperature band
from 20C below to 20C above the OVP threshold, the volt-
age divider is nearly linear with 25mV per C sensitivity.
R
2 provides temperature hysteresis by raising the OVP com-
parator input by R
2 x 20A. For example, if a 22k resistor is
selected for R
2, then the OVP pin voltage will increase by 22k
x 20A = 506mV. The NTC temperature must therefore fall
by 506mV / 25mV per C = 20C before the LM5045 switches
from standby mode to the normal mode.
30145444
FIGURE 16. Remote Standby and Disable Control
30145414
FIGURE 17. Remote Thermal Protection
23
www.national.com
LM5045
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM5045MH/NOPB | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| LM5045MHX | 制造商:TI 制造商全稱:Texas Instruments 功能描述:Full-Bridge PWM Controller with Integrated MOSFET Drivers |
| LM5045MHX/NOPB | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| LM5045SQ | 制造商:TI 制造商全稱:Texas Instruments 功能描述:Full-Bridge PWM Controller with Integrated MOSFET Drivers |
| LM5045SQ/NOPB | 功能描述:電流型 PWM 控制器 Full-Bridge PWM Cntrlr RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
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