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參數(shù)資料
| 型號： | 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 |
| 文件頁數(shù)： | 12/33頁 |
| 文件大?。?/td> | 1018K |
| 代理商： | MAX1887 |
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M
Quick-PWM Slave Controllers for
Multiphase, Step-Down Supplies
12
______________________________________________________________________________________
transition on the TRIG input, the slave controller
’
s
inductor current is below its current-limit threshold, and
the minimum off time has expired. For the MAX1887, a
rising edge on the trigger input (TRIG) initiates a new
cycle. For the MAX1897, the trigger input
’
s polarity is
selected by connecting POL to V
CC
(rising edge) or to
GND (falling edge).
At the slave controller
’
s core is the one-shot that sets
the high-side switch
’
s on-time. This fast, low-jitter one-
shot adjusts the on-time in response to the input volt-
age and the difference between the inductor currents in
the master and the slave. Two identical transconduc-
tance amplifiers (G
MM
= G
MS
) integrate the difference
between the master and slave current-sense signals.
The summed output is connected to COMP, allowing
adjustment of the integration time constant with a com-
pensation capacitor connected at COMP. The resulting
compensation current and voltage may be determined
by the following equations:
(
=
+
where Z
COMP
is the impedance at the COMP output.
The PWM controller uses this integrated signal (V
COMP
)
to set the slave controller
’
s on time. When the master
and slave current-sense signals (CM+ to CM- and CS+
to CS-) become unbalanced, the transconductance
amplifiers adjust the slave controller
’
s on time, allowing
the slave inductor current to increase or decrease until
the current-sense signals are properly balanced.
= (Master
’
s on time) + (Slave
’
s on-time
correction due to current imbalance)
This control algorithm results in balanced inductor cur-
rents with the slave switching frequency synchronized
to the master. Since the master operates at nearly con-
stant frequency, the slave will as well. The benefits of a
constant switching frequency are twofold: first, the fre-
quency can be selected to avoid noise-sensitive
regions of the spectrum; second, the inductor ripple-
current operating point remains relatively constant,
resulting in easy design methodology and predictable
output voltage ripple.
Multiple phase switching effectively distributes the load
among the external components, thereby improving the
overall efficiency. Distributing the load current between
multiple phases lowers the peak inductor current by the
t
K
V
V
K
V
V
K
I
V
ON
COMP
IN
OUT
IN
COMP C
IN
=
=
+
I
V
G
V
V
G
V
V
V
I
COMP
MM
CM
CM
MS
CS
CS
COMP
OUT
COMP COMP
=
)
(
)
+
+
Table 2. Component Suppliers
MANUFACTURER
PHONE
[COUNTRY CODE]
WEBSITE
MOSFETS
Fairchild Semiconductor
International Rectifier
Siliconix
CAPACITORS
Kemet
Panasonic
[1] 888-522-5372
[1] 310-322-3331
[1] 203-268-6261
www.fairchildsemi.com
www.irf.com
www.vishay.com
[1] 408-986-0424
[1] 847-468-5624
www.kemet.com
www.panasonic.com
Sanyo
[65] 281-3226 (Singapore)
[1] 408-749-9714
www.secc.co.jp
Taiyo Yuden
[03] 3667-3408 (Japan)
[1] 408-573-4150
www.t-yuden.com
INDUCTORS
Coilcraft
Coiltronics
Sumida
[1] 800-322-2645
[1] 561-752-5000
[1] 408-982-9660
www.coilcraft.com
www.coiltronics.com
www.sumida.com
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相關代理商/技術參數(shù) |
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|---|---|
| MAX1887EEE | 功能描述:電流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 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 開關頻率:27 KHz 上升時間: 下降時間: 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 開關頻率:27 KHz 上升時間: 下降時間: 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 開關頻率:27 KHz 上升時間: 下降時間: 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 安裝風格:SMD/SMT 封裝 / 箱體:VQFN-48 封裝:Reel |
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