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| 型號(hào)： | SP7651 |
| 英文描述： | Wide Input Voltage Range 3A, 900kHz, Buck Regulator |
| 中文描述： | 寬輸入電壓范圍第3A，900kHz的，降壓穩(wěn)壓器 |
| 文件頁(yè)數(shù)： | 9/12頁(yè) |
| 文件大?。?/td> | 117K |
| 代理商： | SP7651 |
9
Date: 08/25/04
SP7651 Wide Input Voltage Range 3A, 900kHz, Buck Regulator Copyright 2004 Sipex Corporation
APPLICATIONS INFORMATION
2
)
(
)
(
(max)
)
(
V
IN
IN
S
OUT
IN
OUT
C
MAX
OUT
CIN
ESR
out
IN
F
V
V
V
I
R
I
V
+
=
The capacitor type suitable for the output capac-
itors can also be used for the input capacitors.
However, exercise extra caution when tantalum
capacitors are used. Tantalum capacitors are known
for catastrophic failure when exposed to surge
current, and input capacitors are prone to such
surge current when power supplies are connected
“l(fā)ive” to low impedance power sources.
Loop Compensation Design
The open loop gain of the whole system can be
divided into the gain of the error amplifier,
PWM modulator, buck converter output stage,
and feedback resistor divider. In order to cross
over at the selected frequency FCO, the gain of
the error amplifier has to compensate for the
attenuation caused by the rest of the loop at this
frequency.
The goal of loop compensation is to manipulate
loop frequency response such that its gain
crossesover 0db at a slope of -20db/dec. The
first step of compensation design is to pick the
loop cross over frequency.
High cross over frequency is desirable for fast
transient response, but often jeopardizes the
system stability. Cross over frequency should
be higher than the ESR zero but less than 1/5 of
the switching frequency. The ESR zero is con-
tributed by the ESR associated with the output
capacitors and can be determined by:
Z(ESR)
=
1
2
π
C
OUT
R
ESR
The next step is to calculate the complex conju-
gate poles contributed by the LC output filter,
P(LC)
=
1
2
π
L C
OUT
When the output capacitors are of a Ceramic
Type, the SP7651 Evaluation Board requires a
Type III compensation circuit to give a phase
boost of 180
°
in order to counteract the effects of
an under damped resonance of the output filter
at the double pole frequency.
SP7651 Voltage Mode Control Loop with Loop Dynamic
Definitions:
R
ESR
= Output Capacitor Equivalent Series Resistance
R
DC
= Output Inductor DC Resistance
R
RAMP_PP
= SP7651 internal RAMP Amplitude Peak to Peak Voltage
Conditions:
C
Z
2 >> Cp1 and R1 >>
R
Z
3
Output Load Resistance >>
R
ESR
and
R
DC
(SRz2Cz2+1)(SR1Cz3+1)
(SR
ESR
C
OUT
+ 1)
[S^2LC
OUT
+S(R
ESR
+R
DC
) C
OUT
+1]
V
IN
SR1Cz2(SRz3Cz3+1)(SRz2Cp1+1)
V
RAMP_PP
V
OUT
(Volts)
+
_
V
(Volts)
Notes: R
ESR
= Output Capacitor Equivalent Series Resistance.
R
DC
= Output Inductor DC Resistance.
V
RAMP_PP
= SP6132 Internal RAMP Amplitude Peak to Peak Voltage.
Condition: Cz2 >> Cp1 & R1 >> Rz3
Output Load Resistance >> R
ESR
& R
DC
R
2
V
REF
V
OUT
(R
1
+ R
2
)
or
V
FBK
(Volts)
Type III Voltage Loop
Compensation
G
AMP
(s) Gain Block
PWM Stage
G
PWM
Gain
Block
Output Stage
G
OUT
(s) Gain
Block
Voltage Feedback
G
FBK
Gain Block
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SP7652 | Wide Input Voltage Range 6A, 600kHz, Buck Regulator |
| SP7652EB | Evaluation Board Manual |
| SP7652EU | Evaluation Board Manual |
| SP7653 | Wide Input Voltage Range, 1.3MHz,Buck Regulator |
| SP7653ER | Wide Input Voltage Range, 1.3MHz,Buck Regulator |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SP7651_06 | 制造商:SIPEX 制造商全稱(chēng):Sipex Corporation 功能描述:Evaluation Board Manual |
| SP7651_07 | 制造商:SIPEX 制造商全稱(chēng):Sipex Corporation 功能描述:Wide Input Voltage Range 3Amp 900kHz Buck Regulator |
| SP7651EB | 功能描述:電源管理IC開(kāi)發(fā)工具 Wide In Volt Range 3A 900kHz Buck Reg RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類(lèi)型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
| SP7651ER | 制造商:SIPEX 制造商全稱(chēng):Sipex Corporation 功能描述:Evaluation Board Manual |
| SP7651ER/TR | 制造商:SIPEX 制造商全稱(chēng):Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 900kHz, Buck Regulator |
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