- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄384596 > LM20145 (National Semiconductor Corporation) 5A, PowerWise㈢ Adjustable Frequency Synchronous Buck Regulator PDF資料下載
參數(shù)資料
| 型號(hào)： | LM20145 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | 5A, PowerWise㈢ Adjustable Frequency Synchronous Buck Regulator |
| 中文描述： | 第5A，頻率可調(diào)的PowerWise㈢同步降壓穩(wěn)壓器 |
| 文件頁數(shù)： | 11/22頁 |
| 文件大?。?/td> | 601K |
| 代理商： | LM20145 |
perature is exceeded. When activated, typically at 160°C, the
LM20145 tri-states the power FETs and resets soft start. After
the junction cools to approximately 150°C, the part starts up
using the normal start up routine. This feature is provided to
prevent catastrophic failures from accidental device over-
heating.
LIGHT LOAD OPERATION
The LM20145 offers increased efficiency when operating at
light loads. Whenever the load current is reduced to a point
where the peak to peak inductor ripple current is greater than
two times the load current, the part will enter the diode emu-
lation mode preventing significant negative inductor current.
The point at which this occurs is the critical conduction bound-
ary and can be calculated by the following equation:
Several diagrams are shown in
Figure 1
illustrating continu-
ous conduction mode (CCM), discontinuous conduction
mode, and the boundary condition.
It can be seen that in diode emulation mode, whenever the
inductor current reaches zero the SW node will become high
impedance. Ringing will occur on this pin as a result of the LC
tank circuit formed by the inductor and the parasitic capaci-
tance at the node. If this ringing is of concern an additional
RC snubber circuit can be added from the switch node to
ground.
At very light loads, usually below 100 mA, several pulses may
be skipped in between switching cycles, effectively reducing
the switching frequency and further improving light-load effi-
ciency.
30030705
FIGURE 1. Modes of Operation for LM20145
11
www.national.com
L
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM20154 | 4A, 1MHz PowerWise㈢ Synchronous Buck Regulator with SYNCOUT |
| LM20154MH | 4A, 1MHz PowerWise㈢ Synchronous Buck Regulator with SYNCOUT |
| LM20154MHE | 4A, 1MHz PowerWise㈢ Synchronous Buck Regulator with SYNCOUT |
| LM20154MHX | 4A, 1MHz PowerWise㈢ Synchronous Buck Regulator with SYNCOUT |
| LM20242 | 36V, 2A PowerWise㈢ Adjustable Frequency Synchronous Buck Regulator |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM20145_08 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:5A, PowerWise㈢ Adjustable Frequency Synchronous Buck Regulator |
| LM20145CS-A | 制造商:CEC Industries 功能描述:LED, RPL, BULB, AMBER, T-6, E12, Lamp Base Type:Candelabra Screw, LED Color:Ambe |
| LM20145CS-B | 制造商:CEC Industries 功能描述:LED, RPL, BULB, BLUE, T-6, E12; Lamp Base Type:Candelabra Screw; LED Color:Blue; Wavelength Typ:470nm; Power Rating:720mW; Bulb Size:T-6; Supply Voltage:145V; Current Rating:30mA; Average Bulb Life:100000h; Beam Divergence:360 ;RoHS Compliant: No |
| LM20145CS-G | 制造商:CEC Industries 功能描述:LED, RPL, BULB, GREEN, T-6, E12; Lamp Base Type:Candelabra Screw; LED Color:Green; Wavelength Typ:525nm; Power Rating:720mW; Bulb Size:T-6; Supply Voltage:145V; Current Rating:30mA; Average Bulb Life:100000h; Beam Divergence:360 ;RoHS Compliant: No |
| LM20145CS-R | 制造商:CEC Industries 功能描述:LED, RPL, BULB, RED, T-6, E12; Lamp Base Type:Candelabra Screw; LED Color:Red; Wavelength Typ:629nm; Power Rating:720mW; Bulb Size:T-6; Supply Voltage:145V; Current Rating:30mA; Average Bulb Life:100000h; Beam Divergence:360 ;RoHS Compliant: No |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。