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參數資料
| 型號： | FAN5234 |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | Terminal Block; Pitch Spacing:0.197"; Mounting Type:PC Board RoHS Compliant: Yes |
| 中文描述： | 移動友好的PWM / PFM控制器 |
| 文件頁數： | 5/15頁 |
| 文件大小： | 537K |
| 代理商： | FAN5234 |
FAN5234
PRODUCT SPECIFICATION
REV. 1.0.10 5/3/04
5
Figure 2. IC Block Diagram
REF2
PGOOD
EN
C
BOOT
Q1
Q2
5V
VDD
ADAPTIVE
GATE
CONTROL LOGIC
CURRENTPROCESSING
I
OUT
HDRV
SW
LDRV
PGND
BOOT
VDD
HYST
ISNS
VIN
C
OUT
VOUT
PWM/HYST
PWM
S/H
ILIM
R
I
R
SENSE
ILIM det.
HYST
SS
SS
DUTY
CYCLE
CLAMP
Σ
PWM
S
R
Q
RAMP
MODE
OSC
RAMP
CLK
OVP
POR/UVLO
Reference and
Soft Start
FPWM
L
OUT
VREF
EA
PWM/HYST
VSEN
FPWM
VIN
Circuit Description
Overview
The FAN5234 is a PWM controller intended for low voltage
power applications in modern notebook, desktop, and
sub-notebook PCs. The output voltage of the controller can
be set in the range of 0.9V to 5.5V by an external resistor
divider.
The synchronous buck converter can operate from either an
unregulated DC source (such as a notebook battery) with
voltage ranging from 2V to 24V, or from a regulated system
rail. In either mode of operation the IC is biased from a +5V
source. The PWM modulator uses an average current mode
control with input voltage feed-forward for simplified feed-
back loop compensation and improved line regulation. The
controller includes integrated feedback loop compensation
that dramatically reduces the number of external compo-
nents.
Depending on the load level, the converter can operate either
in fixed frequency PWM mode or in a hysteretic mode.
Switch-over from PWM to hysteretic mode improves the
converters' efficiency at light loads and prolongs battery run
time. In hysteretic mode, a comparator is synchronized to the
main clock that allows seamless transition between the oper-
ational modes and reduced channel-to-channel interaction.
The hysteretic mode of operation can be inhibited indepen-
dently using the FPWM pin if variable frequency operation is
not desired.
Oscillator
Table 1. Converter Operating modes
When VIN is from the battery, the oscillator's ramp ampli-
tude is proportional to VIN, providing voltage feed-forward
control for improved loop response. When in either of the
Fixed modes, oscillator's ramp amplitude is fixed. The oper-
ating frequency is then determined according to the connec-
tion on the VIN pin (Table 1).
Initialization and Soft Start
Assuming EN is high, FAN5234 is initialized when VCC
exceeds the rising UVLO threshold. Should VCC drop below
the UVLO threshold, an internal Power-On Reset function
disables the chip.
Mode
Battery
Fixed
300
Fixed
600
F
(Khz)
300
300
SW
Converter
Power
2 to 24V
< 5.5V Fixed
VIN Pin
Battery (>5V)
100K
to GND
600
< 5.5V Fixed
GND
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| FAN5236QSCX | Dual Mobile-Friendly DDR / Dual-output PWM Controller |
相關代理商/技術參數 |
參數描述 |
|---|---|
| FAN5234_10 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Dual Mobile-Friendly PWM / PFM Controller |
| FAN5234MTC | 功能描述:開關變換器、穩壓器與控制器 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 |
| FAN5234MTC_Q | 功能描述:開關變換器、穩壓器與控制器 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 |
| FAN5234MTCX | 功能描述:開關變換器、穩壓器與控制器 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 |
| FAN5234QSC | 功能描述:開關變換器、穩壓器與控制器 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 |
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