- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄385481 > LM3478MM (NATIONAL SEMICONDUCTOR CORP) High Efficiency Low-Side N-Channel Controller for Switching Regulator PDF資料下載
參數(shù)資料
| 型號： | LM3478MM |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | High Efficiency Low-Side N-Channel Controller for Switching Regulator |
| 中文描述： | 1 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | MSOP-8 |
| 文件頁數(shù)： | 18/21頁 |
| 文件大?。?/td> | 624K |
| 代理商： | LM3478MM |
Designing SEPIC Using LM3478
(Continued)
The duty cycle of a SEPIC is given by:
In the above equation, V
is the on-state voltage of the
MOSFET, Q, and V
DIODE
is the forward voltage drop of the
diode.
POWER MOSFET SELECTION
As in boost converter, the parameters governing the selec-
tion of the MOSFET are the minimum threshold voltage,
V
TH(MIN)
, the on-resistance, R
DS(ON)
, the total gate charge,
Q
RSS
, and the maxi-
mum drain to source voltage, V
DS(MAX)
voltage in a SEPIC is given by:
V
SW(PEAK)
= V
IN
+ V
OUT
+ V
DIODE
The selected MOSFET should satisfy the condition:
V
DS(MAX)
>
V
SW(PEAK)
The peak switch current is given by:
The rms current through the switch is given by:
POWER DIODE SELECTION
The Power diode must be selected to handle the peak
current and the peak reverse voltage. In a SEPIC, the diode
peak current is the same as the switch peak current. The
off-state voltage or peak reverse voltage of the diode is V
IN
+ V
. Similar to the boost converter, the average diode
current is equal to the output current. Schottky diodes are
recommended.
SELECTION OF INDUCTORS L1 AND L2
Proper selection of the inductors L1 and L2 to maintain
constant current mode requires calculations of the following
parameters.
Average current in the inductors:
I
L2AVE
= I
OUT
Peak to peak ripple current, to calculate core loss if neces-
sary:
Maintaining the condition I
L
>
i
L
to ensure constant current
mode yields:
10135544
FIGURE 12. Typical SEPIC Converter
L
www.national.com
18
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM3478MMX | High Efficiency Low-Side N-Channel Controller for Switching Regulator |
| LM3485 | Hysteretic PFET Buck Controller |
| LM3485MM | Hysteretic PFET Buck Controller |
| LM3485MMX | Hysteretic PFET Buck Controller |
| LM3488 | 500kHz and 1MHz High Efficiency 1.5A Switching Regulators; Package: SO; No of Pins: 8; Temperature Range: -40?°C to 85?°C |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM3478MM/E7001794 | 制造商:Texas Instruments 功能描述: |
| LM3478MM/NOPB | 功能描述:DC/DC 開關(guān)控制器 HI EFF LOW-SIDE N CH CONTROLLER RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| LM3478MM/NOPB | 制造商:Texas Instruments 功能描述:Pulse Width Modulation (PWM) Controller |
| LM3478MMX | 功能描述:DC/DC 開關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| LM3478MMX/HALF | 制造商:Texas Instruments 功能描述: |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。