SG6903 Fairchild Semiconductor, SG6903 Datasheet

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SG6903

Manufacturer Part Number
SG6903
Description
Manufacturer
Fairchild Semiconductor
Datasheet
Green Mode PFC/Flyback-PWM Controller
FEATURES OVERVIEW
APPLICATIONS
Switching Power Suppliers with Active PFC
High-Power Adaptors
DESCRIPTION
for power supplies consist of boost PFC and flyback
PWM. It requires very few external components to
achieve green-mode operation and versatile protections. It
is available in 16-pin SOP packages.
TYPICAL APPLICATION
© System General Corp.
Version 1.0.1 (IAO33.0061.B0)
Interleaved PFC/PWM switching
Green-mode PFC and PWM operation
No switching of PFC at light loads for best power
saving
Low start-up and operating current
Innovative switching-charge multiplier-divider
Multi-vector control for improved PFC output
transient response
Average-current-mode Control for PFC
Programmable two-level PFC output voltage
PFC over-voltage and under-voltage protections
PFC and PWM feedback open-loop protection
Cycle-by-cycle current limiting for PFC/PWM
Slope compensation for PWM
Constant power limit for PWM
Brownout protection
The highly integrated SG6903 is specially designed
- 1 -
synchronizes the PFC and PWM stages and reduces
switching noise. At light loads, the switching frequency is
continuously decreased to reduce power consumption. If
output loading is further reduced, the PFC stage is turned
off to further reduce power consumption.
scheme provides a fast transient response in a
low-bandwidth PFC loop, in which the overshoot and
undershoot of the PFC voltage are clamped. If the
feedback loop is broken, the SG6903 will shut off PFC to
prevent extra-high voltage on output. Programmable
two-level output voltage control will reduce the PFC
output voltage at low line input to increase the efficiency
of the power supply.
compensation ensures the stability of the current loop
under continuous-conduction-mode operation. Built-in
line-voltage
output-power limit. Hiccup operation during output
overloading is also guaranteed.
functions such as brownout protection and RI pin
open/short.
The
For PFC stage, the proprietary multi-vector control
For the flyback PWM, the synchronized slope
In addition, SG6903 provides complete protection
patented
www.sg.com.tw • www.fairchildsemi.com
compensation
interleave-switching
Product Specification
maintains
September 28, 2007
SG6903
constant
feature

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SG6903 Summary of contents

Page 1

... PFC loop, in which the overshoot and undershoot of the PFC voltage are clamped. If the feedback loop is broken, the SG6903 will shut off PFC to prevent extra-high voltage on output. Programmable two-level output voltage control will reduce the PFC output voltage at low line input to increase the efficiency of the power supply ...

Page 2

... Green Mode PFC/Flyback-PWM Controller MARKING DIAGRAMS SOP =Lead Free SG6903 TP Null=regular package XXXXXXXX: Wafer Lot XXXXXXXXYWWV Y: Year; WW: Week V: Assembly Location ORDERING INFORMATION Part Number Pb-Free Package SG6903SZ 16-pin SOP © System General Corp. Version 1.0.1 (IAO33.0061.B0) Product Specification PIN CONFIGURATION ...

Page 3

... A large capacitor value will result in a narrow bandwidth and hence improve the power factor. Before start-up, this input is used to provide startup current for VDD. For normal operation, this input is used to provide current reference for the multiplier www.sg.com.tw • www.fairchildsemi.com Product Specification SG6903 September 28, 2007 ...

Page 4

... Green Mode PFC/Flyback-PWM Controller BLOCK DIAGRAM © System General Corp. Version 1.0.1 (IAO33.0061.B0) Product Specification - 4 - www.sg.com.tw • www.fairchildsemi.com SG6903 September 28, 2007 ...

Page 5

... Unless noted Test Conditions Min. 0V < V < DD- 15V; OPFC, OPWM open 24KΩ 23 DD-OFF +0 www.sg.com.tw • www.fairchildsemi.com Product Specification SG6903 Unit ℃ ℃ ℃/W ℃ Unit ℃ Typ. Max. Unit µA ...

Page 6

... PWM Frequency OSC F Minimum Frequency in Burst Mode OSC-MINFREQ RI RI Pin Resistance Range RI Pin Open Protection RI OPEN If RI> SG6903 will turn off open RI Pin Short Protection RI SHORT If RI< SG6903 will turn off short VRMS for UVP and RANGE Symbol Parameter RMS AC Voltage Under Voltage Protection ...

Page 7

... Test Conditions V =20V DD V =15V 100mA =13V 100mA =15V; C =5nF ;O/ =15V;C =5nF ;O/ www.sg.com.tw • www.fairchildsemi.com Product Specification SG6903 Min. Typ. Max. Unit 1.5 MHz 70 dB 3 µ 0.25 mA Min. Typ. Max. ...

Page 8

... Test Conditions Min 20V 15V 100mA 13V 100mA 15V 5nF; O/ 15V 5nF; O/ www.sg.com.tw • www.fairchildsemi.com SG6903 Typ. Max. Unit 3.1 3.5 V KΩ 1.2 1.5 mA 4 600 750 ...

Page 9

... Temperature D ebounce Tim 110 125 -40 -25 ℃ Product Specification SG6903 ) Temperature - 110 Temperature ( ) ℃ Over Voltage Protection ( Temperature - ...

Page 10

... Reference V oltage ( 3.05 3.03 3.01 2.99 2.97 2.95 -40 - 110 125 - 10 - Product Specification SG6903 ( Temperature - 110 Temperature ( ) ℃ Temperature - 110 Temperature ( ) ℃ Temperature ...

Page 11

... P eak Current Limit Threshold V oltage Temperature 0.75 0.73 0.71 0.69 0.67 0.65 -40 - 110 125 ) ℃ Product Specification SG6903 Temperature - 110 Temperature ( ) ℃ Tem perature - 110 Tem perature (℃ ...

Page 12

... F alling Time (t 110 110 125 -40 - Product Specification SG6903 ) vs M AXPW M Temperature - 110 Temperature ( ) ℃ Temperature - 110 Temperature ( ) ℃ www.sg.com.tw • www.fairchildsemi.com ...

Page 13

... Lots functions and protections are built in to provide a possible compact design. The following description will describe the operation and function in detail to give an overview of this chip. Start-up Figure 1 shows the start-up circuit of the SG6903. A resistor R is utilized to charge V capacitor through S1. AC ...

Page 14

... PFC and Flyback as a second stage, the output voltage of PFC is usually designed around 250V at low line while it is 390V at high line. This can improve the efficiency at low-line input. In SG6903, the RANGE pin (open-drain structure) is used for the two-level output voltage setting. ...

Page 15

... V RMS = × 2 (1µ From Equation (7), V error amplifier, actually controls the total input power and hence the power delivered to the load. FIG.5 Average current mode control loop - 15 - Product Specification SG6903 1 ---------------------- (6) × × × Iin(rms) × × ...

Page 16

... Once the voltage on the FBPFC pin is over OVP , the OPFC of the SG6903 will be disabled. FBPFC THE OPFC will not be enabled again until the FBPFC voltage falls below OVP ...

Page 17

... System General Corp. Version 1.0.1 (IAO33.0061.B0) Gate Drivers SG6903 output stage is a fast totem-pole gate driver. The output driver is clamped by an internal 18V Zener diode in order to protect the external power MOSFET. (56ms), the - 17 - www.sg.com.tw • ...

Page 18

... Product Specification SG6903 Detail Detail A Typ. Max. 0.069 0.010 0.059 0.016 0.008 0.394 0.157 0.050 0.244 0.050 0.015X45° 0.004 8° ...

Page 19

... Green Mode PFC/Flyback-PWM Controller © System General Corp. Version 1.0.1 (IAO33.0061.B0) Product Specification - 19 - www.sg.com.tw • www.fairchildsemi.com SG6903 September 28, 2007 ...

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