- 您现在的位置：买卖IC网 > PDF目录15363 > ADP1883ARMZ-1.0-R7 (Analog Devices Inc)IC REG CTRLR BUCK PWM CM 10-MSOP PDF资料下载
参数资料
| 型号： | ADP1883ARMZ-1.0-R7 |
| 厂商： | Analog Devices Inc |
| 文件页数： | 23/40页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 10-MSOP |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 占空比： | 45% |
| 电源电压： | 2.75 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： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 标准包装 |
| 其它名称： | ADP1883ARMZ-1.0-R7DKR |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页当前第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页
ADP1882/ADP1883
t ON
SW
INFORMATION
VREG
I
R (TRIMMED)
V IN
To illustrate this feature more clearly, this section describes
one such load transient event—a positive load step—in detail.
During load transient events, the high-side driver output pulse
width stays relatively consistent from cycle to cycle; however,
the off time (DRVL on time) dynamically adjusts according to
the instantaneous changes in the external conditions mentioned.
When a positive load step occurs, the error amplifier (out of
phase of the output, V OUT ) produces new voltage information
Figure 77. Constant On-Time Timer
The constant on time (t ON ) is not strictly constant because it
varies with V IN and V OUT . However, this variation occurs in such
a way as to keep the switching frequency virtually independent
of V IN and V OUT .
The t ON timer uses a feedforward technique, applied to the constant
on-time control loop, making it pseudo-fixed frequency to a first
order. Second-order effects, such as dc losses in the external power
MOSFETs (see the Efficiency Consideration section), cause some
variation in frequency vs. load current and line voltage. These
effects are shown in Figure 23 to Figure 34. The variations in
frequency are much reduced, compared with the variations
generated when the feedforward technique is not used.
The feedforward technique establishes the following relationship:
at its output (COMP). In addition, the current-sense amplifier
senses new inductor current information during this positive
load transient event. The error amplifier’s output voltage
reaction is compared to the new inductor current information
that sets the start of the next switching cycle. Because current
information is produced from valley current sensing, it is
sensed at the down ramp of the inductor current, whereas the
voltage loop information is sensed through the counter action
upswing of the error amplifier’s output (COMP).
The result is a convergence of these two signals (see Figure 78),
which allows an instantaneous increase in switching frequency
during the positive load transient event. In summary, a positive
load step causes V OUT to transient down, which causes COMP to
transient up and, therefore, shortens the off time. This resultant
increase in frequency during a positive load transient helps to
f SW =
1
quickly bring V OUT back up in value and within the regulation
K
where f SW is the controller switching frequency (300 kHz,
600 kHz, and 1.0 MHz).
The t ON timer senses V IN and V OUT to minimize frequency
variation with V IN and V OUT as previously explained. This
provides a pseudo fixed frequency that is explained in the
Pseudo-Fixed Frequency section. To allow headroom for V IN
and V OUT sensing, adhere to the following two equations:
V DD ≥ V IN /8 + 1.5
V DD ≥ V OUT /4
For typical applications where V DD = 5 V, these equations are
not relevant; however, for lower V DD inputs, care may be
required.
PSEUDO-FIXED FREQUENCY
The ADP1882/ADP1883 employ a constant on-time control
scheme. During steady state operation, the switching frequency
stays relatively constant, or pseudo-fixed. This is due to the one-
shot t ON timer, which produces a high-side PWM pulse with
a fixed duration, given that external conditions such as input
voltage, output voltage, and load current are also at steady state.
window.
Similarly, a negative load step causes the off time to lengthen in
response to V OUT rising. This effectively increases the inductor
demagnetizing phase, helping to bring V OUT within regulation.
In this case, the switching frequency decreases, or experiences
a foldback, to help facilitate output voltage recovery.
Because the ADP1882/ADP1883 can respond rapidly to sudden
changes in load demand, the recovery period in which the output
voltage settles back to its original steady state operating point is
much quicker than it would be for a fixed-frequency equivalent .
Therefore, using a pseudo-fixed frequency results in signifi-
cantly better load transient performance than using a fixed
frequency.
LOAD CURRENT
DEMAND
CS AMP
OUTPUT
During load transients, the frequency momentarily changes for
the duration of the transient event so that the output comes back
ERROR AMP
OUTPUT
VALLEY
TRIP POINTS
within regulation more quickly than if the frequency were fixed
PWM OUTPUT
f SW
> f SW
or if it were to remain unchanged. After the transient event is
complete, the frequency returns to a pseudo-fixed value to
a first-order.
Rev. 0 | Page 23 of 40
Figure 78. Load Transient Response Operation
相关PDF资料 |
PDF描述 |
|---|---|
| RCM30DCAD-S189 | CONN EDGECARD 60POS R/A .156 SLD |
| VE-J14-EW-F3 | CONVERTER MOD DC/DC 48V 100W |
| H2BXG-10105-V8-ND | JUMPER-H1501TR/A3048V/X 5" |
| VE-J14-EW-F1 | CONVERTER MOD DC/DC 48V 100W |
| GSM15DTBS-S189 | CONN EDGECARD 30POS R/A .156 SLD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP190 | 制造商:AD 制造商全称:Analog Devices 功能描述:Logic Controlled, High-Side Power Switches |
| ADP190ACBZ-R7 | 功能描述:IC CTRLR HIGH SIDE PWR SW 4WLCSP RoHS:是 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 内部开关 系列:- 标准包装:2,500 系列:- 类型:高端 输入类型:非反相 输出数:1 导通状态电阻:35 毫欧 电流 - 输出 / 通道:- 电流 - 峰值输出:3A 电源电压:2.7 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:14-TSSOP 包装:带卷 (TR) 其它名称:MIC2545A-1YTSTRMIC2545A-1YTSTR-ND |
| ADP190CB-EVALZ | 功能描述:BOARD EVAL ADP190 RoHS:是 类别:编程器，开发系统 >> 评估演示板和套件 系列:- 标准包装:1 系列:- 主要目的:数字电位器 嵌入式:- 已用 IC / 零件:AD5258 主要属性:- 次要属性:- 已供物品:板 相关产品:AD5258BRMZ1-ND - IC POT DGTL I2C1K 64P 10MSOPAD5258BRMZ10-ND - IC POT DGTL I2C 10K 64P 10MSOPAD5258BRMZ100-ND - IC POT DGTL I2C 100K 64P 10MSOPAD5258BRMZ50-ND - IC POT DGTL I2C 50K 64P 10MSOPAD5258BRMZ1-R7-ND - IC POT DGTL I2C 1K 64P 10MSOPAD5258BRMZ10-R7-ND - IC POT DGTL I2C 10K 64P 10MSOPAD5258BRMZ50-R7-ND - IC POT DGTL I2C 50K 64P 10MSOPAD5258BRMZ100-R7-ND - IC POT DGTL I2C 100K 64P 10MSOP |
| ADP191ACBZ-R7 | 功能描述:IC CTLR HIGH LSIDE PWR SW 4WLCSP RoHS:是 类别:集成电路 (IC) >> PMIC - MOSFET，电桥驱动器 - 内部开关 系列:- 标准包装:2,500 系列:- 类型:高端 输入类型:非反相 输出数:1 导通状态电阻:35 毫欧 电流 - 输出 / 通道:- 电流 - 峰值输出:3A 电源电压:2.7 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:14-TSSOP 包装:带卷 (TR) 其它名称:MIC2545A-1YTSTRMIC2545A-1YTSTR-ND |
| ADP191CB-EVALZ | 功能描述:EVAL BOARD FOR ADP191 RoHS:是 类别:编程器，开发系统 >> 评估演示板和套件 系列:- 标准包装:1 系列:- 主要目的:电信，线路接口单元（LIU） 嵌入式:- 已用 IC / 零件:IDT82V2081 主要属性:T1/J1/E1 LIU 次要属性:- 已供物品:板，电源，线缆，CD 其它名称:82EBV2081 |
发布紧急采购，3分钟左右您将得到回复。