- 您现在的位置：买卖IC网 > PDF目录298814 > ADP3170JRU-REEL (ANALOG DEVICES INC) SWITCHING CONTROLLER, PDSO20 PDF资料下载
参数资料
| 型号： | ADP3170JRU-REEL |
| 厂商： | ANALOG DEVICES INC |
| 元件分类： | 稳压器 |
| 英文描述： | SWITCHING CONTROLLER, PDSO20 |
| 封装： | TSSOP-20 |
| 文件页数： | 3/16页 |
| 文件大小： | 177K |
| 代理商： | ADP3170JRU-REEL |
REV. 0
ADP3170
–11–
R
RR
R
kM
k
A
T
OGM
B
A
=
==
1
11
1
888
1
29 7
12 83
––
.
––
.
(13)
Choosing the nearest 1% resistor value gives RA = 12.7 k.
COUT Selection
The required equivalent series resistance (ESR) and capacitance
drive the selection of the type and quantity of the output capaci-
tors. The ESR of the output filter capacitor bank must be equal
to or less than the specified output resistance of the voltage
regulator (3.2 m
). The capacitance must be large enough that
the voltage across the capacitor, which is the sum of the resistive
and capacitive voltage drops, does not move below or above the
initial resistive step while the inductor current ramps up or
down to the value corresponding to the new load current. One
can use, for example, eight ZA series capacitors from Rubycon,
which have a maximum ESR of 24 m
. These eight 1000 F
capacitors would give an ESR of 3 m
.
As long as the capacitance of the output capacitor is above a
critical value, and the regulating loop is compensated with
Analog Devices’ proprietary compensation technique (ADOPT),
the actual value has no influence on the peak-to-peak deviation
of the output voltage to a full step change in the load current.
The critical capacitance can be calculated as follows:
The equivalent capacitance of the eight ZA series Rubycon
capacitors is 8
× 1 mF = 8 mF. In this case, the total capacitance
is safely above the critical value.
Feedback Loop Compensation Design for ADOPT
Optimized compensation of the ADP3170 allows the best pos-
sible containment of the peak-to-peak output voltage deviation.
The output current slew rate of any practical switching power
converter is inherently limited by the inductor to a value much
less than the slew rate of the load. Therefore, any sudden change
of load current will initially flow through the output capacitors,
and assuming that the capacitance of the output capacitor is
larger than the critical value defined by Equation 14, this will
produce a peak output voltage deviation equal to the ESR of the
output capacitor times the load current change.
The optimal implementation of voltage positioning, ADOPT,
will create an output impedance of the power converter that is
entirely resistive over the widest possible frequency range,
including dc, and equal to the specified dc output resistance.
With the wide-band resistive output impedance the output
voltage will droop in proportion with the load current at any
load current slew rate; this ensures the optimal positioning
and allows the minimization of the output capacitor.
With an ideal current-mode controlled converter, where the
inductor current would respond without delay to the command
signal, the resistive output impedance could be achieved by
having a single-pole roll-off of the voltage gain of the voltage-
error amplifier. The pole frequency must coincide with the ESR
zero of the output capacitor.
The ADP3170 uses peak-current control, which is known to
have a nonideal, frequency-dependent command signal-to-
inductor current transfer function. The frequency dependence
manifests in the form of a pair of complex conjugate poles at
one-half of the switching frequency. A purely resistive output
impedance could be achieved by canceling the complex conju-
gate with zeros at the same complex frequencies and adding a
third pole equal to the ESR zero of the output capacitor. Such a
compensating network would be quite complicated. Fortu-
nately, in practice, it is sufficient to cancel the pair of complex
conjugate poles with a single real zero placed at one-half of the
switching frequency.
Although the end result is not a perfectly resistive output imped-
ance, the remaining frequency dependence causes only a slight
percentage of deviation from the ideal resistive response. The
single-pole and single-zero compensation can be easily imple-
mented by terminating the gm error amplifier with the parallel
combination of a resistor (RT) and a series RC network. The
value of the terminating resistor RT was determined previously;
the capacitance and resistance of the series RC network are
calculated as follows:
C
ESR
R
C
mF
m
k
nF
OC
OUT
T
OC
=
×
=
×
=
83
888
27
.
(15)
The closest standard value is 2.7 nF. The series resistance is:
R
Cf
R
nF
kHz
Z
OC
MIN
Z
=
××
=
××
=
2
2 7
188
1255
π
.
(16)
The nearest standard 5% resistor value is 1.2 k
. Note that this
resistor is only required when COUT approaches CCRIT (within
25% or less). In this example, COUT >> CCRIT, and RZ can
therefore be omitted.
C
I
RV
V
L
C
A
mV
HmF
OUT CRIT
O
OUT
OUT CRIT
()
(–)
.( .
[–
])
.
=
×+
×
=
×+
×=
23
32
18
29
14 06
(14)
相关PDF资料 |
PDF描述 |
|---|---|
| ADP3189JCPZ-R7 | SWITCHING CONTROLLER, 5000 kHz SWITCHING FREQ-MAX, QCC40 |
| ADP5022ACBZ-2-R7 | 1.05 A SWITCHING REGULATOR, 3500 kHz SWITCHING FREQ-MAX, PBGA16 |
| ADR02BKS-R | 1-OUTPUT THREE TERM VOLTAGE REFERENCE, 5 V, PDSO5 |
| ADR35-21AR | ALUMINUM ALLOY, TIN FINISH, WIRE TERMINAL |
| ADS-112/883 | 1-CH 12-BIT FLASH METHOD ADC, PARALLEL ACCESS, CDIP24 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP3170JRU-REEL7 | 制造商:Analog Devices 功能描述: |
| ADP3170JRUZ-R7 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Analog Devices 功能描述: |
| ADP3170JRUZ-REEL7 | 功能描述:IC CTRLR VRM 8.5 W/REG 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
| ADP3171 | 制造商:AD 制造商全称:Analog Devices 功能描述:Synchronous Buck Controller with Dual Linear Regulator Controllers |
| ADP3171JR | 制造商:Rochester Electronics LLC 功能描述:1.2V VTT BUCK CNTRLR W/2 LDOS & PWR GOOD - Bulk |
发布紧急采购，3分钟左右您将得到回复。