參數(shù)資料
型號(hào): FAN5240QSCX
廠商: FAIRCHILD SEMICONDUCTOR CORP
元件分類: 穩(wěn)壓器
英文描述: Multi-Phase PWM Controller for AMD Mobile Athlon TM and Duron TM
中文描述: SWITCHING CONTROLLER, 345 kHz SWITCHING FREQ-MAX, PDSO28
封裝: QSOP-28
文件頁(yè)數(shù): 10/19頁(yè)
文件大?。?/td> 447K
代理商: FAN5240QSCX
FAN5240
PRODUCT SPECIFICATION
10
REV. 1.1.7 8/29/02
Current Processing Section
The following discussion refers to Figure 6.
Setting RSENSE
Each phase current is sampled about 200nS after the SW
node crosses 0V. For proper converter operation, choose an
RSENSE value of:
which is about 1K for the components in Figure 1.
Active Droop
The core converter incorporates a proprietary output voltage
droop method for optimum handling of fast load transients
found in modern processors.
“Active droop” or voltage positioning is now widely used in
the computer power applications. The technique is based on
raising the converter voltage at light load in anticipation of a
step increase in load current, and conversely, lowering
VCORE in anticipation of a step decrease in load current.
With Active Droop, the output voltage varies with the load as
if a resistor were connected in series with the converter’s out-
put, in other words, it's effect is to raise the output resistance
of the converter.
Figure 5. Active Droop
To get the most from the Active Droop, its magnitude should
be scaled to match the output capacitor’s ESR voltage drop.
Active Droop allows the size and cost of the output capaci-
tors required to handle CPU current transients to be reduced.
The reduction may be almost a factor of 2 when compared to
a system without Active Droop.
R
SENSE
R
----------------------------------------
I
40
μ
A
=
1.2
V
C
I
LOAD
V
DROOP
I
MAX
V
DROOP
I
MAX
ESR
×
=
(6)
Figure 6. Current Limit and Active Droop Circuits
LDRV1
PGND1
ISNS1
in +
in D
2.5V
ILIM det. 1
R
SENSE
V to I
ISNS1
5
ISNS1
8
I2 =
ILIM
ILIM
0.9V
R
ILIM
ILIM mirror
S/H
ISNS2
5
To A1 (+)
ISNS1
ISNS2
A B
A-B
B-A
ISNS2-ISNS1
ISNS1-ISNS2
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
FAN5242_AAB3026B WAF 制造商:Fairchild Semiconductor Corporation 功能描述:
FAN5242MTC 功能描述:開(kāi)關(guān)變換器、穩(wěn)壓器與控制器 DC/DC RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開(kāi)關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
FAN5242MTCX 功能描述:開(kāi)關(guān)變換器、穩(wěn)壓器與控制器 PWM Controller RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開(kāi)關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
FAN5242QSC 功能描述:開(kāi)關(guān)變換器、穩(wěn)壓器與控制器 DC/DC RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開(kāi)關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
FAN5242QSCX 功能描述:開(kāi)關(guān)變換器、穩(wěn)壓器與控制器 PWM Controller RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開(kāi)關(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel