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參數(shù)資料
| 型號(hào)： | LM21215MHX |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 23.5 A SWITCHING REGULATOR, 525 kHz SWITCHING FREQ-MAX, PDSO20 |
| 封裝： | TSSOP-20 |
| 文件頁(yè)數(shù)： | 4/24頁(yè) |
| 文件大?。?/td> | 512K |
| 代理商： | LM21215MHX |
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FIGURE 2. PGOOD Conditions
LIGHT LOAD OPERATION
The LM21215 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 device will enter the diode em-
ulation 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 3 illustrating continu-
ous conduction mode (CCM), discontinuous conduction
mode (DCM), 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 100mA, several pulses may
be skipped in between switching cycles, effectively reducing
the switching frequency and further improving light-load effi-
ciency.
www.national.com
12
LM21215
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM21215MHX/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM212B | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Optoelectronic |
| LM212D | 制造商:TI 制造商全稱:Texas Instruments 功能描述:OPERATIONAL AMPLIFIERS/BUFFERS |
| LM212H | 制造商:Motorola Inc 功能描述: |
| LM212JG | 制造商:TI 制造商全稱:Texas Instruments 功能描述:OPERATIONAL AMPLIFIERS/BUFFERS |
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