參數(shù)資料
型號(hào)： MAX1887
廠商： Maxim Integrated Products, Inc.
英文描述： Quick-PWM Slave Controllers for Multiphase, Step-Down
中文描述： Quick-PWM從控制器，用于多相、降壓型電源
文件頁(yè)數(shù)： 20/33頁(yè)
文件大?。?/td> 1018K
代理商： MAX1887
M
Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies
20
______________________________________________________________________________________
current-limit threshold. This is acceptable since the
slave
’
s inductor current limit only serves as a fail-safe in
case the master and slave inductor currents become
significantly unbalanced during a transient.
The basic operating conditions are determined using
the same calculations provided in any Quick-PWM reg-
ulator data sheet. The valley of the inductor current
(I
LIMIT(VALLEY)
) occurs at I
LOAD(MAX)
divided by the
number of phases minus half of the peak-to-peak
inductor current:
where the peak-to-peak inductor current may be deter-
mined by the following equation:
The master
’
s high current-limit threshold must be set
high enough to support the maximum load current,
even when the master
’
s current-limit threshold is at its
minimum tolerance value, as described in the master
controller
’
s data sheet. Most Quick-PWM controllers
that may be chosen as the master controller use the
low-side MOSFET
’
s on-resistance to sense the inductor
current. In these applications, the worst-case maximum
value for R
DS(ON)
plus some margin for the rise in
R
DS(ON)
over temperature must be used to determine
the master
’
s current-limit threshold. A good general rule
is to allow 0.5% additional resistance for each
°
C of
temperature rise. Set the master current-limit threshold
to support the maximum load current for the maximum
R
DS(ON)
and minimum current-limit tolerance value:
V
ITHM(HIGH)
≥
(I
LIMIT(VALLEY)
)R
DS(ON)(MAX)
where V
ITHM
, the master
’
s current-limit threshold, is typ-
ically 1/10th the voltage seen at the master
’
s ILIM input
(V
ITHM
= 0.1 x V
LIM(MASTER)
, see the master con-
troller
’
s data sheet). Connect a resistive voltage-divider
from the master controller
’
s internal reference to GND,
with the master
’
s ILIM input connected to the center tap
(Figure 5). Use 1% tolerance resistors in the divider with
10μA to 20μA DC bias current to prevent significant
errors due to the ILIM pin
’
s input current:
V
A
20
μ
Configure the slave controller so its LIMIT output begins
to roll off after the master current-limit threshold occurs:
where V
ITHS
, the slave
’
s current-limit threshold, is pre-
cisely one-tenth the voltage seen at the slave
’
s ILIM
input (V
ITHS
= 0.1
V
ILIM(SLAVE)
). Connect a second
resistive voltage-divider from the master controller
’
s
internal reference to GND, with the slave
’
s ILIM input
connected to the center tap (Figure 5). The external
adjustment range of 400mV to 1.5V corresponds to a
V
R
V
R
I
ITHS
CM
ITHM HIGH
(
DS ON MAX
(
INDUCTOR
≥
+
)
)(
)
R
V
A
R
V
V
R
ILIM MASTER
(
B
ILIM MASTER
(
10
μ
A
REF MASTER
(
ILIM MASTER
(
B
)
)
)
)
1
≤
≤
=
I
V
V
V
L
V f
INDUCTOR
OUT
IN
OUT
=
(
)
I
I
I
LIMIT VALLEY
(
LOAD MAX
η
INDUCTOR
2
)
(
)
≥
MAX1718
MAX1887
MAX1897
SLAVE
CONTROLLER
ILIM
LIMIT
MASTER
CONTROLLER
REF
ILIM
R
C
R
LIMIT
C
LIMIT
R
D
R
A
R
B
C
REF
Figure 5. Setting the Adjustable Current Limits
V
R
R
R
V
V
R
+
(
R
R
R
R
V
V
R
R
R
V
ITHM HIGH
(
B
+
A
B
REF
ITHM HIGH
(
B
LIMIT
LIMIT
//
A
B
REF
ITHS
D
+
C
D
REF
)
)
//
=
=
)
=
1
10
1
10
1
10
相關(guān)PDF資料
PDF描述
MAX1889EGE Triple-Output TFT LCD Power Supply with Fault Protection
MAX1889ETE Triple-Output TFT LCD Power Supply with Fault Protection
MAX1889 Fixed-Point Digital Signal Processor 256-BGA
MAX1896 1.4MHz SOT23 Current-Mode Step-Up DC-DC Converter
MAX1896EUT-T Fixed-Point Digital Signal Processor 532-FCBGA
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1887EEE 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
MAX1887EEE+ 功能描述:電流型 PWM 控制器 CDMA Cellular/PCS System Power Supplies RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
MAX1887EEE+T 功能描述:電流型 PWM 控制器 CDMA Cellular/PCS System Power Supplies RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
MAX1887EEE-T 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關(guān)頻率:27 KHz 上升時(shí)間: 下降時(shí)間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TSSOP-14
MAX1888EUA 功能描述:其他電源管理 RoHS:否 制造商:Texas Instruments 輸出電壓范圍: 輸出電流:4 mA 輸入電壓范圍:3 V to 3.6 V 輸入電流: 功率耗散: 工作溫度范圍:- 40 C to + 110 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-48 封裝:Reel
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*