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参数资料
| 型号： | LT3782EUFD |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 4 A SWITCHING CONTROLLER, 533 kHz SWITCHING FREQ-MAX, PQCC28 |
| 封装： | 4 X 5 MM, PLASTIC, MO-220, QFN-28 |
| 文件页数： | 5/20页 |
| 文件大小： | 223K |
| 代理商： | LT3782EUFD |
LT3782
13
3782fg
From a known power dissipated in the power MOSFET, its
junction temperature can be obtained using the following
formula:
TJ = TA + PFET RTH(JA)
The RTH(JA) to be used in this equation normally includes
the RTH(JC) for the device plus the thermal resistance from
the case to the ambient temperature (RTH(CA)). This value
of TJ can then be compared to the original, assumed value
used in the iterative calculation process.
Input Capacitor Choice
The input capacitor must have high enough voltage and
ripple current ratings to handle the maximum input voltage
and RMS ripple current rating. The input ripple current in
a boost circuit is very small because the input current is
continuous. With 2-phase operation, the ripple cancellation
will further reduce the input capacitor ripple current rating.
The ripple current is plotted in Figure 5. Please note that
the ripple current is normalized against
I
norm =
V
IN
Lf
s
Output Capacitor Selection
The voltage rating of the output capacitor must be greater
than the maximum output voltage with sufcient derat-
ing. Because the ripple current in output capacitor is a
pulsating square wave in a boost circuit, it is important
that the ripple current rating of the output capacitor be
high enough to deal with this large ripple current. Figure
6 shows the output ripple current in the 1- and 2-phase
designs. As we can see, the output ripple current of a
2-phase boost circuit reaches almost zero when the duty
cycle equals 50% or the output voltage is twice as much as
the input voltage. Thus the 2-phase technique signicantly
reduces the output capacitor size.
Figure 6. Normalized Output RMS Ripple Currents in Boost
Converter: 1-Phase and 2-Phase. IOUT Is the DC Output Current.
0.1
I ORIPPLE
/I
OUT
0.9
3782 F05
0.3
0.5
0.7
0.8
0.2
0.4
0.6
3.25
3.00
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
0.25
0
DUTY CYCLE OR (1-VIN/VOUT)
1-PHASE
2-PHASE
Figure 5. Normalized Input Peak-to-Peak Ripple Current
DUTY CYCLE
0
ΔI
IN
/I
NORM
1.00
0.90
0.80
0.60
0.70
0.50
0.40
0.30
0.20
0.10
0
0.8
3782 F04
0.2
0.4
0.6
1.0
1-PHASE
2-PHASE
APPLICATIONS INFORMATION
I
norm =
V
IN
Lf
s
The RMS Ripple Current is About 29% of
the Peak-to-Peak Ripple Current.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3782EUFD#PBF | 功能描述:IC REG CTRLR BST PWM CM 28-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LT3782EUFD#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 28-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LT3782EUFD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-UP DC/DC Controller |
| LT3782EUFD-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-UP DC/DC Controller |
| LT3782EUFD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:2-Phase Step-UP DC/DC Controller |
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