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參數(shù)資料
| 型號： | LT1432 |
| 廠商： | Linear Technology Corporation |
| 英文描述： | 5V High Efficiency Step-Down Switching Regulator Controller |
| 中文描述： | 5V的高效率降壓型開關(guān)穩(wěn)壓控制器 |
| 文件頁數(shù)： | 25/28頁 |
| 文件大?。?/td> | 611K |
| 代理商： | LT1432 |
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25
LT1432
5
μ
s/DIV
POSITIVE TOU
U
INPUT VOLTAGE (V)
0
1
O
2
1.0
1.5
2.0
2.5
3.0
5
10
15
20
LT1432 F23
25
T
J
= 25°C
R
LIM
= 0.02
V
OUT
= 0 (SHORT CIRCUIT)
V
OUT
= 1%
0
0
I
DIODE
1A/DIV
I
SWITCH
1A/DIV
Figure 23. Positive-to-Negative Converter
Output Current
tor current is diverted through the catch diode to the
output. Figure 24 shows switch current (1A/DIV) with the
upper waveform, and catch diode current (which is deliv-
ered to the output) in the lower waveform, with a +5V input
and 1A load. Note that switch, inductor, and diode currents
are much higher than output current as required by the fact
that current is delivered to the output during only part of
a switch cycle. An approximate formula for peak switch
current required in an inverting design is:
The first term (2.29A) represents the minimum switch
current required if the inductor were infinitely large. A
finite inductor value requires additional switch current.
The 0.4A represents one-half the peak-to-peak inductor
ripple current. The end result is that peak switch current is
almost three times output load current. This multiplier
drops rapidly at higher input voltages, so worst case is
calculated at lower input voltage.
Figure 25 shows the efficiency of this converter. At higher
input voltages and modest output currents efficiency
hovers around 85%, quite good for a 5V output inverter.
Low input voltage reduces efficiency because of increased
currents in the switch, catch diode, and inductor. High
input voltage and low output current also show lower
efficiency due to quiescent currents in the ICs. Note that
the efficiency is actually significantly improved in this
regard over a more conventional design because the
V
F
= Forward voltage of catch diode
R
SW
= Switch on-resistance
L = Inductor value
f = Switching frequency
If V
IN
is 4.7V (minimum),
V
F
= 0.4V, R
SW
= 0.25
,
L = 50
μ
H, f = 60kHz, and I
OUT
= 1A;
Figure 24. Positive-to-Negative Converter
Switch and Diode Current
I
I
1
V
(
V
V
(
V –I
R
V
V
V
V
2 L f V
V
SW PEAK
OUT
OUT
F
OUT
)
SW
IN
OUT
IN
IN
OUT
+
IN
OUT
)
=
+
+
)
+
)
+
(
)
I
1 1
5
0.4
)
4.7 –1 0.25
4.7
5
4.7
4.75 5
=
2 50E
60E
4.75
5
2.29
0.4
2.69A
SW PEAK
–6
3
)
=
+
+
+
(
)
+
+
(
)
=
+
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PDF描述 |
|---|---|
| LT1432-3.3 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| LT1432CN8 | 5V High Efficiency Step-Down Switching Regulator Controller |
| LT1432CN8-3.3 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| LT1432CS8 | 5V High Efficiency Step-Down Switching Regulator Controller |
| LT1432CS8-3.3 | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LT1432-3.3 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:3.3V High Efficiency Step-Down Switching Regulator Controller |
| LT1432CN8 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:5V High Efficiency Step-Down Switching Regulator Controller |
| LT1432CN8-3.3 | 功能描述:IC REG CTRLR BUCK PWM 8-DIP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,000 系列:- PWM 型:電壓模式 輸出數(shù):1 頻率 - 最大:1.5MHz 占空比:66.7% 電源電壓:4.75 V ~ 5.25 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 85°C 封裝/外殼:40-VFQFN 裸露焊盤 包裝:帶卷 (TR) |
| LT1432CS8 | 制造商:Linear Technology 功能描述: |
| LT1432CS8-3.3 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:3.3V High Efficiency Step-Down Switching Regulator Controller |
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