參數(shù)資料
型號(hào)： SG6901A
廠商： Fairchild Semiconductor Corporation
元件分類： 基準(zhǔn)電壓源/電流源
英文描述： PFC / Flyback PWM Controller
中文描述： 功率因數(shù)校正/反激式PWM控制器
文件頁(yè)數(shù)： 16/18頁(yè)
文件大?。?/td> 716K
代理商： SG6901A
Product Specification
PFC / Flyback PWM Controller
SG6901A
System General Corp.
Version 1.0.1 (IAO33.0062.B0)
- 16 -
www.sg.com.tw www.fairchildsemi.com
September 26, 2007
FIG. 6 V
RMS
Controlled Current Limiting
The peak current of the I
SENSE
is given by (V
RMS
<1.05V):
S
P
R
P
SENSE_peak
0.2V
-
R
(I
I
×
=
------------------
(9)
Flyback PWM and Slope Compensation
As shown in Figure 7, peak-current-mode control is
utilized for flyback PWM. The SG6901A inserts a
synchronized 0.5V ramp at the beginning of each
switching cycle. This built-in slope compensation ensures
stable operation for continuous current-mode operation.
FIG. 7 Peak Current Control Loop
When the IPWM voltage, across the sense resistor,
reaches the threshold voltage (0.9V), the OPWM is turned
off after a small propagation delay t
PD-PWM
.
To improve stability or prevent sub-harmonic oscillation,
a synchronized positive-going ramp is inserted at every
switching cycle.
Limited Power Control
Every time the output of power supply is shorted or
overloaded, the FBPWM voltage increases. If the
FBPWM voltage is higher than a designed threshold,
FB
OPEN-LOOP
(4.5V) for longer than t
OPEN-PWM
(56ms), the
OPWM is turned off.
As long as the voltage on the VDD pin is larger than
V
DD-OFF
(minimum operating voltage), the OPWM is not
enabled. This protection is reset every t
OPEN-PWM-Hiccup
interval. A low-frequency hiccup mode protection
prevents the power supply from being overheated under
overloading conditions
.
Over-Temperature Protection
SG6901A provides an OTP pin for over-temperature
protection. A constant current is output from this pin. If R
I
is equal to 24K
, the magnitude of the constant current is
100μA. An external NTC thermistor must be connected
from this pin to ground, as shown as Figure 8. When the
OTP voltage drops below V
OTP-OFF
(1.2V), SG6901A is
disabled and does not recover until OTP voltage exceeds
V
OTP-ON
(1.4V).
FIG. 8 OTP Function
Soft-Start
During start-up of PWM stage, the SS pin charges an
external capacitor with a constant current source. The
voltage on FBPWM is clamped by the SS voltage during
start-up. In the event of a protected condition and/or
PWM disabled, the SS pin quickly discharges.
Gate Drivers
SG6901A output stage is a fast totem-pole gate driver.
The output driver is clamped by an internal 18V Zener
diode to protect the external power MOSFET.
相關(guān)PDF資料
PDF描述
SG6901ASZ PFC / Flyback PWM Controller
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SG6961DZ Power Factor Controller
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SG6901ASZ 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 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(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
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(guān)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(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
SG6903SZ 功能描述:開關(guān)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(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
SG6905 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Green mode PFC/Flyback-PWM Controller
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