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参数资料
| 型号： | L7981ATR |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING REGULATOR, DSO8 |
| 封装： | 3 X 3 MM, 1.08 MM HEIGHT, ROHS COMPLIANT, HSOP-8 |
| 文件页数： | 30/44页 |
| 文件大小： | 1315K |
| 代理商： | L7981ATR |
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Application ideas
L7981
36/44
Doc ID 15182 Rev 3
Equation 35
where ISW is the average current in the embedded power MOSFET in the on time.
To chose the right value of the inductor and to manage transient output current, that for short
time can exceed the maximum output current calculated by Equation 35, also the peak
current in the power MOSFET has to be calculated. The peak current, showed in Equation
36, must be lower than the minimum current limit (3.7 A)
Equation 36
Where r is defined as the ratio between the inductor current ripple and the inductor DC
current:
So in the buck boost topology the maximum output current depends on the application
conditions (firstly input and output voltage, secondly switching frequency and inductor
value).
In Figure 34. the maximum output current for the above configuration is depicted varying the
input voltage from 4.5 V to 28 V.
The dashed line considers a more accurate estimation of the duty cycles given by Equation
37, where power losses across diodes, external power MOSFET, internal power MOSFET
are taken into account.
I
SW
I
OUT
1D
–
-------------
3 A
<
=
I
SW,PK
I
OUT
1D
–
-------------
1
r
2
---
+
3.7A
<
=
r
V
OUT
I
OUT
LF
SW
------------------------------------
1D
–
()
2
=
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相关代理商/技术参数 |
参数描述 |
|---|---|
| L7981ATR/BLK | 制造商:STMicroelectronics 功能描述:3 A STEP-DOWN SWITCHING REGULATO - Tape and Reel 制造商:STMicroelectronics 功能描述:STMicroelectronics L7981ATR/BLK Interface Misc |
| L7981TR | 功能描述:直流/直流开关调节器 3A DC 4.5 V to 28 V Adj 0.6V 250 kHz RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| L7983 | 制造商:Leviton Manufacturing Co 功能描述: |
| L7985 | 功能描述:线性稳压器 - 标准 2A Step Down REG 4.5V to 38V 250 KHz RoHS:否 制造商:STMicroelectronics 输出类型: 极性: 输出电压:1.8 V 输出电流:150 mA 负载调节: 最大输入电压:5.5 V 线路调整率: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOT-323-5L |
| L7985A | 功能描述:直流/直流开关调节器 2A DC 4.5V to 38V 250 KHz Step-Down RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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