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參數資料
| 型號： | SG6901ASZ |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | PFC / Flyback PWM Controller |
| 中文描述： | POWER FACTOR CONTROLLER, 68 kHz SWITCHING FREQ-MAX, PDSO20 |
| 封裝： | 0.300 INCH, ROHS COMPLIANT, MS-013AC, SOP-20 |
| 文件頁數： | 13/18頁 |
| 文件大小： | 716K |
| 代理商： | SG6901ASZ |
Product Specification
PFC / Flyback PWM Controller
OPERATION DESCRIPTION
SG6901A
System General Corp.
Version 1.0.1 (IAO33.0062.B0)
- 13 -
www.sg.com.tw www.fairchildsemi.com
September 26, 2007
SG6901A is a highly integrated PFC/PWM combination
controller. Many functions and protections are built in to
provide a compact design. The following sections
describe the operation and function.
Switching Frequency and Current
Sources
The switching frequency of SG6901A can be
programmed by the resistor R
I
connected between RI pin
and GND. The relationship is:
(kHz)
)
(k
R
1560
F
I
OSC
=
-----------
(1)
For example, a 24K
resistor R
I
results in a 65KHz
switching frequency. Accordingly, a constant current, I
T
,
flows through R
I
:
(mA)
)
(k
R
1.2V
I
I
T
=
----------------
(2)
I
T
is used to generate internal current reference.
Line Voltage Detection (VRMS)
Figure 1 shows a resistive divider with low-pass filtering
for line-voltage detection on the VRMS pin. The V
RMS
voltage is used for the PFC multiplier, brownout
protection, and range control.
For brownout protection, the SG6901A is disabled with
195ms delay time if the voltage V
RMS
drops below 0.8V.
For PFC multiplier and range control, refer to section
below for more details.
FIG.1 Line Voltage Detection Circuit
PFC Output Voltage Control (RANGE)
For an universal input (90 ~ 264V
AC
) power supply
applying active boost PFC and flyback as a second stage,
the output voltage of PFC is usually designed around
250V at low line and 390V at high line. This can improve
the efficiency at low-line input. The RANGE pin
(open-drain structure) is used for the two-level output
voltage setting.
Figure 2 shows the RANGE output that programs the PFC
output voltage. The RANGE output is shorted to ground
when the V
RMS
voltage exceeds V
RMS-H
(1.95V) while it is
of high impedance (open) whenever the V
RMS
voltage
drops below V
RMS-L
(1.6V). The output voltages can be
designed using equations:
(
)
(
)
V
3
R
//
R
R
//
R
R
V
Ground
Range
V
3
R
R
R
V
Open
Range
C
B
C
B
A
O
B
B
A
O
×
+
=
=
×
+
=
=
----
(3)
FIG.2 Range Control Two-Level Output Voltage
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相關代理商/技術參數 |
參數描述 |
|---|---|
| SG6902 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Green-Mode PFC / Flyback-PWM Controller |
| SG6902SZ | 功能描述:開關變換器、穩(wěn)壓器與控制器 Grn Mode PFC/Flyback 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 |
| SG6903SZ | 功能描述:開關變換器、穩(wěn)壓器與控制器 Highly-Integrated Grn Mode PWM Cntrl 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 |
| SG6905 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Green mode PFC/Flyback-PWM Controller |
| SG6905SY | 制造商:Rochester Electronics LLC 功能描述: 制造商:Fairchild Semiconductor Corporation 功能描述: |
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