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參數(shù)資料
| 型號： | SP7650 |
| 英文描述： | Wallmount ULTRX Series Fiberglass Enclosure; NEMA Type:1, 2, 4, 4X, 12, 13; Enclosure Material:Fiberglass; External Height:24.61"; External Width:24.11"; External Depth:12.64"; Enclosure Color:Light Gray |
| 中文描述： | 寬輸入電壓范圍第3A，300kHz的降壓穩(wěn)壓器 |
| 文件頁數(shù)： | 7/12頁 |
| 文件大?。?/td> | 121K |
| 代理商： | SP7650 |
7
Date: 08/24/04
SP7650 Wide Input Voltage Range 3A, 300kHz, Buck Regulator Copyright 2004 Sipex Corporation
APPLICATIONS INFORMATION
Inductor Selection
There are many factors to consider in selecting
the inductor including core material, inductance
vs. frequency, current handling capability, effi-
ciency, size and EMI. In a typical SP7650 cir-
cuit, the inductor is chosen primarily for value,
saturation current and DC resistance. Increasing
the inductor value will decrease output voltage
ripple, but degrade transient response. Low in-
ductor values provide the smallest size, but
cause large ripple currents, poor efficiency and
more output capacitance to smooth out the larger
ripple current. The inductor must be able to
handle the peak current at the switching fre-
quency without saturating, and the copper resis-
tance in the winding should be kept as low as
possible to minimize resistive power loss. A
good compromise between size, loss and cost is
to set the inductor ripple current to be within
20% to 40% of the maximum output current.
The switching frequency and the inductor oper-
ating point determine the inductor value as fol-
lows:
(max)
(max)
(max)
K
)
(
OUT
r
S
IN
OUT
IN
F
OUT
I
V
V
V
V
L
=
where:
f
S
= switching frequency
Kr = ratio of the AC inductor ripple current to
the maximum output current
The peak to peak inductor ripple current is:
L
F
V
V
V
(
V
I
S
IN
OUT
IN
OUT
PP
(max)
(max)
)
=
Once the required inductor value is selected, the
proper selection of core material is based on
peak inductor current and efficiency require-
ments. The core must be large enough not to
saturate at the peak inductor current
2
(max)
PP
OUT
PEAK
I
I
I
+
=
and provide low core loss at the high switching
frequency. Low cost powdered iron cores have
a gradual saturation characteristic but can intro-
duce considerable AC core loss, especially when
the inductor value is relatively low and the
ripple current is high. Ferrite materials, although
more expensive, and have an abrupt saturation
characteristic with the inductance dropping
sharply when the peak design current is ex-
ceeded. Nevertheless, they are preferred at high
switching frequencies because they present very
low core loss while the designer is only required
to prevent saturation. In general, ferrite or
molypermalloy materials are a better choice for
all but the most cost sensitive applications.
Optimizing Efficiency
The power dissipated in the inductor is equal to
the sum of the core and copper losses. To mini-
mize copper losses, the winding resistance needs
to be minimized, but this usually comes at the
expense of a larger inductor. Core losses have a
more significant contribution at low output cur-
rent where the copper losses are at a minimum,
and can typically be neglected at higher output
currents where the copper losses dominate. Core
loss information is usually available from the
magnetic vendor. Proper inductor selection can
affect the resulting power supply efficiency by
more than 15%!
The copper loss in the inductor can be calculated
using the following equation:
I
P
(
)
(
=
WINDING
R
RMS
L
Cu
L
2
)
where
I
L(RMS)
is the RMS inductor current that
can be calculated as follows:
I
L(RMS)
= I
OUT(max)
1 + 1
(
I
PP
)
2
3 I
OUT(max)
相關PDF資料 |
PDF描述 |
|---|---|
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| SP7652EB | Evaluation Board Manual |
| SP7652EU | Evaluation Board Manual |
| SP7653 | Wide Input Voltage Range, 1.3MHz,Buck Regulator |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| SP7650_05 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Evaluation Board Manual |
| SP7650_06 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 300kHz, Buck Regulator |
| SP7650EB | 功能描述:電源管理IC開發(fā)工具 Eval Board for SP7650 Series RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| SP7650ER | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP7650ER/TR | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 300kHz, Buck Regulator |
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