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參數(shù)資料
| 型號(hào)： | MP1517 |
| 廠商： | Monolithic Power Systems, Inc. |
| 英文描述： | 3A, 25V, 1.1MHz Step-Up Converter |
| 中文描述： | 第3A，25V的，為1.1MHz升壓轉(zhuǎn)換器 |
| 文件頁數(shù)： | 8/13頁 |
| 文件大?。?/td> | 323K |
| 代理商： | MP1517 |
MP1517 – 3A, 25V, 1.1MHz STEP-UP CONVERTER
MP1517 Rev. 1.4
4/28/2006
www.MonolithicPower.com
8
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
2006 MPS. All Rights Reserved.
The DC loop gain is:
A
VDC
=
2
OUT
FB
LOAD
IN
VEA
V
V
R
V
A
7
×
×
×
×
Where V
FB
is the feedback regulation threshold.
There is also a right-half-plane zero (f
RHPZ
) that
exists in the continuous conduction mode
(inductor current does not drop to zero on each
cycle) step-up converters. The frequency of the
right-half plane zero is:
f
RHPZ
=
2
2
OUT
LOAD
V
IN
π
L
2
R
×
V
×
×
×
To stabilize the regulation control loop, the
crossover frequency (The frequency where the
loop gain drops to 0dB or a gain of 1) should be
less than half of f
RHPZ
and should be at most
75KHz. f
RHPZ
is at its lowest frequency at
maximum output load current.
In some cases, an output capacitor with a high
capacitance
and
high
equivalent
series
resistance (ESR) is used, then a second
compensation capacitor (from COMP to SGND)
is required to compensate for the zero
introduced by the output capacitor ESR. The
extra capacitor is required if the ESR zero is
less than 4x the crossover frequency. The ESR
zero frequency is:
f
ZESR
=
ESR
R
C2
×
2
1
×
π
×
If this is the case, calculate the second
compensation capacitor by the equation:
C6 =
3
R
R
C2
ESR
×
For most applications C6 is not required.
Typical
values
for
components are:
the
compensation
C3 = 10nF
R3 = 2.2k
SEPIC CONVERTER COMPONENT
SELECTION
Selecting the Input Capacitor
An input capacitor is required to supply the AC
ripple current to the inductor, while limiting
noise at the input source. The input capacitor
selection is the same as that in the General
Purpose Component Selection section above.
Selecting the Inductors
The SEPIC converter inductors (refer to Figure
4) are required to store energy, and generate
an output voltage that is less than or greater
than the input voltage. If a coupled inductor is
used in a SEPIC converter, then the mutual
inductance of each winding forces each
inductor
to
become
inductance. Therefore smaller inductance can
be used with a coupled inductor. But the core
saturation of the coupled inductors is related to
the sum of both inductor currents.
twice
the
original
There are two current paths to the internal
N-Channel MOSFET switch in a SEPIC
converter. One is from L1 and the other is from
L2.
Each inductor’s ripple current can be defined
as:
I
f
D
V
1
L
SW
IN
×
×
=
I
f
D)
1
×
V
2
L
SW
UT
O
×
=
IN
D
OUT
V
D
OUT
V
V
V
V
D
+
+
+
=
Where V
D
is the voltage drop on diode D1, and
I is the peak to peak inductor ripple current.
Set
I to approximately 20% of the maximum
switch current. Each inductor’s peak current is:
IN
D
OUT
LOAD
)
PEAK
(
L
V
V
V
I
2
I
I
+
×
+
=
IN
D
IN
LOAD
I
)
PEAK
(
2
L
V
V
V
2
I
I
+
×
+
=
The total of these two currents is the total
switch current, and should be less than the
minimum device current limit of 3A.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MP1517DR | 制造商:MPS 制造商全稱:Monolithic Power Systems 功能描述:3A, 25V, 1.1MHz Step-Up Converter |
| MP1517DR-LF-P | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 3A Switch / 25Vout Step-Up Converter 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(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| MP1517DR-LF-Z | 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 3A Switch / 25Vout Step-Up Converter 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(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| MP1518 | 制造商:MPS 制造商全稱:Monolithic Power Systems 功能描述:Fixed Frequency White LED Driver |
| MP1518DG | 制造商:MPS 制造商全稱:Monolithic Power Systems 功能描述:Fixed Frequency White LED Driver |
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