- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄375724 > FAN5250 (Fairchild Semiconductor Corporation) Mobile Processor Core-Voltage Regulator PDF資料下載
參數(shù)資料
| 型號： | FAN5250 |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | Mobile Processor Core-Voltage Regulator |
| 中文描述： | 移動處理器核心電壓調(diào)節(jié)器 |
| 文件頁數(shù)： | 11/17頁 |
| 文件大?。?/td> | 469K |
| 代理商： | FAN5250 |
FAN5250
REV. 1.1.6 3/12/03
11
Figure 8. Active Droop
Additionally, the CPU power dissipation is also slightly
reduced as it is proportional to the applied voltage squared
and even slight voltage decrease translates to a measurable
reduction in power dissipated.
Figure 9. Effect of Active Droop on ESR
The Crusoe
processor regulation window including
transients is specified as +5%…–2%. To accommodate the
droop, the output voltage of the converter is raised by about
3.25% at no load as shown below (R24 = 1K and
R25 = 30.1K):
Figure 10. Setting the No-Load Output Voltage Rise
The converter response to the load step is shown in Figure
11. At zero load current, the output voltage is raised ~50mV
above nominal value of 1.35V. When the load current
increases, the output voltage droops down approximately
55mV. Due to use of Active Droop, the converter’s output
voltage adaptively changes with the load current allowing
better utilization of the regulation window.
Figure 11. Converter Response to 5A Load Step
The current through R
SENSE
resistor (ISNS) is sampled
shortly after Q2 is turned on. That current is held, and then
injected (with a 1/48 gain) into the inverting path of the error
amp to produce an offset to the sensed output voltage at
V
CORE
+ proportional to the load current.
Setting the Current Limit
A ratio of ISNS is also compared to the current established
when a 1.2 V internal reference drives the ILIM pin. The
threshold is determined at the point when the
Since
therefore,
Since the tolerance on the current limit is largely dependent
on the ratio of the external resistors it is fairly accurate if the
voltage drop on the Switching Node side of R
SENSE
is an
accurate representation of the load current. When using the
MOSFET as the sensing element, the variation of R
DS(ON)
causes proportional variation in the ISNS. This value not
only varies from device to device, but also has a typical
junction temperature coefficient of about 0.4%/°C
(consult the MOSFET datasheet for actual values), so the
actual current limit set point will decrease proportional to
increasing MOSFET die temperature. The same discussion
applies to the V
DROOP
calculation, which has an additional
initial error of ±20% due to its value being determined by
a ratio between R
SENSE
and the internal 100K resistor.
1.2
V
C
I
LOAD
V
DROOP
I
MAX
V
ESR
upper lim
lower lim
ILOAD
Vout
(no droop)
Vout
droop
ESR
upper lim
lower lim
V
ESR
16
VCORE+
V CORE
R24
R25
C
OUT
1
2
I
CPU
= 0A...5.0A
lower limit
V
CPU
= 1.35V
upper limit
Ch2 2.0A
M50
μ
s
Ch1 50mV
V
DROOP
100K
I
R
SENSE
)
×
--------------------------------------------
×
=
V
DROOP
2083
I
--------------------------------------------
R
SENSE
)
×
×
=
(9a)
(9b)
--------------
---------------------
4
×
3
>
ISNS
I
--------------------------------------------
R
SENSE
)
×
=
I
LIMIT
LIM
------------
4
3
--
8
----------------------------------------------------
100
DS ON
R
+
(
)
×
)
×
×
=
(10)
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| FAN5250QSC | Mobile Processor Core-Voltage Regulator |
| FAN5250QSCX | Mobile Processor Core-Voltage Regulator |
| FAN5307MPX | High-Efficiency Step-Down DC-DC Converter |
| FAN5307S18X | High-Efficiency Step-Down DC-DC Converter |
| FAN5307SX | High-Efficiency Step-Down DC-DC Converter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| FAN5250_ADB3026B WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FAN5250_AZB3026B WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FAN5250QSC | 功能描述:DC/DC 開關(guān)控制器 DC/DC RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| FAN5250QSC_Q | 功能描述:DC/DC 開關(guān)控制器 DC/DC RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
| FAN5250QSCX | 功能描述:DC/DC 開關(guān)控制器 Crusoe Processor Core Voltage RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。