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参数资料
| 型号： | ADP1829ACPZ-R7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 22/28页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 32LFCSP |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 2 |
| 频率 - 最大： | 720kHz |
| 占空比： | 93% |
| 电源电压： | 3 V ~ 20 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 32-VFQFN 裸露焊盘，CSP |
| 包装： | 标准包装 |
| 产品目录页面： | 791 (CN2011-ZH PDF) |
| 配用： | ADP1829-EVALZ-ND - BOARD EVALUATION ADP1829 |
| 其它名称： | ADP1829ACPZ-R7DKR |
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ADP1829
Data Sheet
?
V CSS ? 0 . 8 V ? 1 ? e RC SS
?
Because of the finite output current drive of the error amplifier,
C I needs to be less than 10 nF. If it is larger than 10 nF, choose a
larger R TOP and recalculate R Z and C I until C I is less than 10 nF.
?
?
t
?
?
?
(48)
Because C HF << C I , combining Equation 29 and Equation 39
yields
The soft start period ends when the voltage on the soft start pin
reaches 0.6 V. Substituting 0.6 V for V SS and solving for the
C HF ?
f Z2 ?
? ?
0 . 6 V ? 0 . 8 V ? 1 ? e 90 kΩ ? C SS ? ?
?
?
1
(44)
π f SW R Z
Next, calculate the feedforward capacitor, C FF. . Assume R FF <<
R TOP , then Equation 28 is simplified to
1
(45)
2 π C FF R TOP
Solving C FF in Equation 45 yields
number of RC time constants,
t SS
? ?
t SS ? 1 . 386 RC SS
Because R = 90 kΩ,
C SS ? t SS ? 8 μF/ sec
(49)
(50)
(51)
C FF ?
1
2 π R TOP f Z2
(46)
where t SS is the desired soft start time in seconds.
VOLTAGE TRACKING
where f Z2 is obtained from Equation 40 or Equation 41.
The feedforward resistor, R FF , can be calculated by combining
Equation 30 and Equation 39
The ADP1829 includes a tracking feature that prevents an
output voltage from exceeding a master voltage. This is
especially important when the ADP1829 is powering separate
power supply voltages on a single integrated circuit, such as the
R FF ?
1
π C FF f SW
(47)
core and I/O voltages of a DSP or microcontroller. In these
cases, improper sequencing can cause damage to the load.
Check that the calculated component values are reasonable. For
instance, capacitors smaller than about 10 pF should be avoided.
In addition, the ADP1829 error amplifier has finite output
current drive, so R Z values less than 3 kΩ and C I values greater
than 10 nF should be avoided. If necessary, recalculate the
compensation network with a different starting value of R TOP .
If R Z is too small and C I is too big, start with a larger value of R TOP .
This compensation technique should yield a good working
solution.
In general, aluminum electrolytic capacitors have high ESR, and
a Type II compensation is adequate. However, if several aluminum
electrolytic capacitors are connected in parallel, producing a low
effective ESR, then Type III compensation is needed. In addition,
ceramic capacitors have very low ESR, in the order of a few
milliohms. Type III compensation is needed for ceramic output
capacitors. Type III compensation offers better performance
than Type II in terms of more low frequency gain and more
phase margin and less high frequency gain at the cross-over
frequency.
The ADP1829 tracking input is an additional positive input to
the error amplifier. The feedback voltage is regulated to the lower of
the 0.6 V reference or the voltage at TRK, so a lower voltage on
TRK limits the output voltage. This feature allows implementation
of two different types of tracking: coincident tracking, where
the output voltage is the same as the master voltage until the
master voltage reaches regulation, or ratiometric tracking, where
the output voltage is limited to a fraction of the master voltage.
In all tracking configurations, the master voltage should be
higher than the slave voltage.
Note that the soft start time setting of the master voltage should
be longer than the soft start of the slave voltage. This forces the
rise time of the master voltage to be imposed on the slave voltage.
If the soft start setting of the slave voltage is longer, the slave
comes up more slowly and the tracking relationship is not seen
at the output. The slave channel should still have a soft start
capacitor to give a small but reasonable soft start time to protect
in case of restart after a current-limit event.
V OUT
For a more exact method or to optimize for other system
characteristics, a number of references and tools are available
COMP
R TOP
from your Analog Devices, Inc. applications support team.
SOFT START
FB
R BOT
The ADP1829 uses an adjustable soft start to limit the output
voltage ramp-up period, thus limiting the input inrush current.
The soft start is set by selecting the capacitor, C SS , from SS1 and
SS2 to GND. The ADP1829 charges C SS to 0.8 V through an
internal 90 kΩ resistor. The voltage on the soft start capacitor
ERROR
AMPLIFIER
TRK
0.6V
SS
DETAIL VIEW OF
R TRKT
R TRKB
MASTER
VOLTAGE
while it is charging is
Rev. C | Page 22 of 28
ADP1829
Figure 30. Voltage Tracking
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1829-BL1-EVZ | 制造商:Analog Devices 功能描述:BLANK ADISIMPOWER EVAL ADP1829 - Boxed Product (Development Kits) |
| ADP1829-BL2-EVZ | 制造商:Analog Devices 功能描述:Evaluation Board For Dual Interleaved Step-Down DC-To-DC Controller With Tracking 制造商:Analog Devices 功能描述:BLANK ADISIMPOWER EVAL ADP1829 - Boxed Product (Development Kits) |
| ADP1829-EVALZ | 功能描述:BOARD EVALUATION ADP1829 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| ADP1850 | 制造商:AD 制造商全称:Analog Devices 功能描述:Wide Range Input, Dual/Two-Phase, DC-to-DC Synchronous Buck Controller |
| ADP1850ACPZ | 制造商:Analog Devices 功能描述:IC BUCK CNTRL SYNC 2PH 32LFCSP |
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