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參數資料
| 型號： | FAN5231 |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 穩壓器 |
| 英文描述： | Micropower 5V, 100mA Low Dropout Linear Regulator |
| 中文描述： | 1 A SWITCHING REGULATOR, 345 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封裝： | QSOP-28 |
| 文件頁數： | 9/17頁 |
| 文件大小： | 360K |
| 代理商： | FAN5231 |
FAN5231
REV. 1.1.1 8/15/01
9
not the same because the CPU current is significantly lower
as it is illustrated by the following equaton.
I
CPU
= K
CPU
V
CPUi
F
CPUi
K
F
;
Where, K
CPU
— is a processor constant; V
CPUi
— is proces-
sor operating voltage; F
CPUi
— is processor clock frequency;
K
F
— is a coefficient that varies from 0 to 1 and indicates
how heavily processor is engaged by the software; i — is a
denominator associated with the processor mode of opera-
tion (performance or battery optimized).
Figure 4.
This leads to deterioration of the droop benefits in the
battery-optimized mode where they are mostly appreciable,
Fig. 3.
Figure 5.
The FAN5231 incorporates a new proprietary droop
technique specially designed for the SpeedStep-enabled
converters and provides mode-compensated, relatively equal
droop in both, the performance and the battery-optimized
modes. The droop is set as a fraction of the VID programmed
voltage and the gain in the current loop is different for each
VID combination, those providing the droop, which is
compensated for the voltage and the frequency changes
associated with the different CPU modes of operation.
Figure 6.
To accommodate the droop the output voltage of core
converter is raised 2% at no load conditions. The resistor
connected to ISEN1 pin programs the amount of droop.
This resistor sets the gain in the current feedback loop. The
droop is scaled to 5.5% of the VID code when current into
ISEN1 pin equals 75μA.
The output voltage waveforms with droop subjected to load
step are shown on Fig. 4–Fig. 6 .
Feedback Loop Compensation
Due to implemented average current mode control, the
modulator has a single pole response with -1 slope at
frequency determined by load
where Ro – is load resistance, Co – is load capacitance. For
this type of modulator Type 2 compensation circuit is usually
sufficient. To reduce number of external components and
remove the burden at determining compensation components
from a system designer, both PWM controllers have
internally compensated error amplifiers.
Figure 7 shows Type 2 amplifier and its response along with
responses of current mode modulator and the converter. The
Type 2 amplifier, in addition to the pole at origin, has a zero-
pole pair that causes a flat gain region at frequencies in
between the zero and the pole.
Ch1 50mV
Ch2 5.0A
M50μs
1
2
V
CPU
=1.6V
I
CPU
=0.3A>>18A
Ch1 50mV
Ch2 5.0A
M50μs
1
2
V
CPU
=1.35V
I
CPU
= 0.3A>>13 5A
Ch1 50mV
Ch2 5.0A
M50μs
1
2
V
CPU
=1.00V
I
CPU
=0.3A>>12.0A
R
CS
I
R
75
A
)
--------------------------------------
=
F
PO
2
R
0
C
0
-------------1
=
’
F
Z
2
R
2
C
1
-------------1
6
kHz
=
=
;
F
P
2
R
2
C
1
-------------1
600
kHz
=
=
;
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相關代理商/技術參數 |
參數描述 |
|---|---|
| FAN5231 WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FAN5231QSC | 功能描述:開關變換器、穩壓器與控制器 QSOP-28 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 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| FAN5231QSCX | 功能描述:開關變換器、穩壓器與控制器 QSOP-28 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 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| FAN5232 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Adjustable PWM Buck Controller for LCD PCs |
| FAN5232_CBC3116B WAF | 制造商:Fairchild Semiconductor Corporation 功能描述: |
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