- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄224618 > NX2117ACUTR (MICROSEMI CORP-ANALOG MIXED SIGNAL GROUP) SWITCHING CONTROLLER, PDSO10 PDF資料下載
參數(shù)資料
| 型號： | NX2117ACUTR |
| 廠商： | MICROSEMI CORP-ANALOG MIXED SIGNAL GROUP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING CONTROLLER, PDSO10 |
| 封裝： | LEAD FREE, PLASTIC, MSOP-10 |
| 文件頁數(shù)： | 13/14頁 |
| 文件大?。?/td> | 405K |
| 代理商： | NX2117ACUTR |
NX2116/2116A/2116B/2117/2117A
8
Rev. 3.0
03/14/06
It should be considered that the proposed equa-
tion is based on ideal case, in reality, the droop or over-
shoot is typically more than the calculation. The equa-
tion gives a good start. For more margin, more capaci-
tors have to be chosen after the test. Typically, for high
frequency capacitor such as high quality POSCAP es-
pecially ceramic capacitor, 20% to 100% (for ceramic)
more capacitors have to be chosen since the ESR of
capacitors is so low that the PCB parasitic can affect
the results tremendously. More capacitors have to be
selected to compensate these parasitic parameters.
Compensator Design
Due to the double pole generated by LC filter of the
power stage, the power system has 180o phase shift ,
and therefore, is unstable by itself. In order to achieve
accurate
output
voltage
and
fast
transient
response,compensator is employed to provide highest
possible bandwidth and enough phase margin.Ideally,the
Bode plot of the closed loop system has crossover fre-
quency between1/10 and 1/5 of the switching frequency,
phase margin greater than 50o and the gain crossing
0dB with -20dB/decade. Power stage output capacitors
usually decide the compensator type. If electrolytic
capacitors are chosen as output capacitors, type II com-
pensator can be used to compensate the system, be-
cause the zero caused by output capacitor ESR is lower
than crossover frequency. Otherwise type III compensa-
tor should be chosen.
A. Type III compensator design
For low ESR output capacitors, typically such as
Sanyo oscap and poscap, the frequency of ESR zero
caused by output capacitors is higher than the cross-
over frequency. In this case, it is necessary to compen-
sate the system with type III compensator. The follow-
ing figures and equations show how to realize the type III
compensator by transconductance amplifier.
Z1
42
Z2
2
33
P1
33
P2
12
4
12
1
F
...(11)
2
RC
1
F
...(12)
2
(R
R )C
1
F
...(13)
2
RC
1
F
...(14)
CC
2R
CC
=
×π ××
=
×π ×+×
=
×π ××
=
×
×π ××
+
where FZ1,FZ2,FP1 and FP2 are poles and zeros in
the compensator. Their locations are shown in figure 4.
The transfer function of type III compensator for
transconductance amplifier is given by:
e
mf
OUT
m
in
in1
V
1 gZ
V
1 gZ
Z /R
×
=
+×+
For the voltage amplifier, the transfer function of
compensator is
e
f
OUT
in
V
Z
VZ
=
To achieve the same effect as voltage amplifier,
the compensator of transconductance amplifier must
satisfy this condition: R
4>>2/gm. And it would be desir-
able if R
1||R2||R3>>1/gm can be met at the same time.
Zin
Zf
Vout
Vref
Fb
R2
R1
R3
R4
C3
C1
C2
Ve
gm
Figure 3 - Type III compensator using
transconductance amplifier
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| NX25P16-VSI | 16M X 1 FLASH 2.7V PROM, PDSO8 |
| NX3225SA-100.000M-STD-CSR-3 | QUARTZ CRYSTAL RESONATOR, 100 MHz |
| NX5A0AE01 | MALE, STRAIGHT TWO PART BOARD CONNECTOR, PRESS FIT |
| NX5B0AE01 | MALE, STRAIGHT TWO PART BOARD CONNECTOR, PRESS FIT |
| NX5C0AE01 | MALE, STRAIGHT TWO PART BOARD CONNECTOR, PRESS FIT |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| NX2117CUTR | 制造商:MICROSEMI 制造商全稱:Microsemi Corporation 功能描述:SYNCHRONOUS PWM CONTROLLER WITH CURRENT LIMIT, POWER GOOD & OVER VOLTAGE |
| NX2119 | 制造商:MICROSEMI 制造商全稱:Microsemi Corporation 功能描述:SYNCHRONOUS PWM CONTROLLER WITH CURRENT LIMIT PROTECTION |
| NX2119A | 制造商:MICROSEMI 制造商全稱:Microsemi Corporation 功能描述:SYNCHRONOUS PWM CONTROLLER WITH CURRENT LIMIT PROTECTION |
| NX2119ACSTR | 制造商:MICROSEMI 制造商全稱:Microsemi Corporation 功能描述:SYNCHRONOUS PWM CONTROLLER WITH CURRENT LIMIT PROTECTION |
| NX2119ACUTR | 制造商:MICROSEMI 制造商全稱:Microsemi Corporation 功能描述:SYNCHRONOUS PWM CONTROLLER WITH CURRENT LIMIT PROTECTION |
發(fā)布緊急采購，3分鐘左右您將得到回復。