參數(shù)資料
型號(hào): LM20124
廠商: National Semiconductor Corporation
英文描述: 4A, 1MHz PowerWise㈢ Synchronous Buck Regulator
中文描述: 第4A,半導(dǎo)體PowerWise㈢1MHz的同步降壓穩(wěn)壓器
文件頁數(shù): 11/20頁
文件大小: 492K
代理商: LM20124
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 LM20124 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.
30014205
FIGURE 1. Modes of Operation for LM20124
11
www.national.com
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM20124_08 制造商:NSC 制造商全稱:National Semiconductor 功能描述:4A, 1MHz PowerWise㈢ Synchronous Buck Regulator
LM20124EVAL 功能描述:電源管理IC開發(fā)工具 LM20124 EVAL BOARD RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
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