參數(shù)資料
型號： SP6139EU-L
英文描述： Wide Input, 1.3MHz Synchronous PWM Controller
中文描述： 寬輸入，1.3MHz同步PWM控制器
文件頁數(shù)： 7/13頁
文件大?。?/td> 148K
代理商： SP6139EU-L
7
Date: 12/20/04 SP6139 Wide Input, 1.3MHz Synchronous PWM Controller Copyright 2004 Sipex Corporation
APPLICATIONS INFORMATION
Inductor Selection
There are many factors to consider in selecting
the inductor including cost, efficiency, size and
EMI. In a typical SP6139 circuit, 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 inductor values provide
the smallest size, but cause large ripple currents,
poor efficiency and more output capacitance to
smooth out the larger ripple current. The induc-
tor must also be able to handle the peak current
at the switching frequency without saturating,
and the copper resistance 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:
Fs = 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, on the
other hand, are more expensive and have an
abrupt saturation characteristic with the induc-
tance dropping sharply when the peak design
current is exceeded. Nevertheless, they are pre-
ferred at high switching frequencies because
they present very low core loss and the design
only needs to prevent saturation. In general,
ferrite or molypermalloy materials are better
choice for all but the most cost sensitive appli-
cations.
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.
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
SP619 High Current Power Switch
SP619EK-L High Current Power Switch
SP6200EM5-1.5 Micropower, 100mA and 200mA CMOS LDO Regulators
SP6200EM5-1.8 Micropower, 100mA and 200mA CMOS LDO Regulators
SP6200EM5-2.5 Micropower, 100mA and 200mA CMOS LDO Regulators
相關代理商/技術參數(shù)
參數(shù)描述
SP6139EU-L/TR 功能描述:開關變換器、穩(wěn)壓器與控制器 Wide Input, 1.3MHz Synchronous RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
SP615 制造商:Power-One 功能描述: 制造商:Power-One 功能描述:POWER SUPPLY
SP6153ER1-L 制造商:Exar Corporation 功能描述:
SP615BABT 制造商:Power-One 功能描述:
SP618 制造商:Power-One 功能描述:
發(fā)布緊急采購，3分鐘左右您將得到回復。

采購需求

(若只采購一條型號，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

*型號 *數(shù)量 廠商 批號 封裝
添加更多采購

我的聯(lián)系方式

*
*
*