SG6905SZ

Manufacturer Part NumberSG6905SZ
DescriptionIC PWM CTLR PFC/FLYBACK 20-SOP
ManufacturerFairchild Semiconductor
SG6905SZ datasheet
 

Specifications of SG6905SZ

ModeAverage CurrentFrequency - Switching65kHz
Current - Startup10µAVoltage - Supply16 V ~ 20 V
Operating Temperature-40°C ~ 105°CMounting TypeSurface Mount
Package / Case20-SOIC (7.5mm Width)Lead Free Status / RoHS StatusLead free / RoHS Compliant
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SG6905
Green Mode PFC/Flyback-PWM Controller
Features
Interleaved PFC/PWM Switching
Green Mode PWM Operation
Low Startup and Operating Current
Innovative Switching-Charge Multiplier-Divider
Average-Current-Mode Control for PFC
PFC Over-Voltage and Under-Voltage Protections
PFC Remote On/Off Control
PFC and PWM Feedback Open-Loop Protection
Cycle-by-Cycle Current Limiting for PFC/PWM
Slope Compensation for PWM
Constant Power Limit for PWM
Power-On Sequence Control
Brownout Protection
Over-Temperature Protection
Applications
Switching Power Suppliers with Active PFC
High-Power Adaptors
LCD TV Applications
Ordering Information
Operating
Part Number
Temperature Range
SG6905SY
-40°C to +105°C
For Fairchild’s definition of “green” Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html.
© 2007 Fairchild Semiconductor Corporation
SG6905 • Rev. 1.1.2
Description
The highly integrated SG6905 is specially designed for
power supplies consisting of boost PFC and flyback
PWM. It requires very few external components to
achieve
green-mode
protections. It is available in 20-pin SOP package.
The
proprietary
synchronizes the PFC and PWM stages and reduces
switching noise. At light loads, the switching frequency
is
continuously
consumption.
For PFC stage, the proprietary multi-vector control
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 SG6905 shuts off PFC to
prevent extra-high voltage on output.
For
the
flyback
compensation ensures the stability of the current loop
under continuous-conduction-mode operation. Built-in
line-voltage compensation maintains constant output-
power limit. Hiccup operation during output overloading
is also guaranteed.
During startup, the RDY (ready) is pulled low until the
PFC output voltage reaches the setting level. This
signal can be used to control the second power stage
for proper power-on sequence.
In addition, SG6905 provides complete protection
functions, such as brownout protection and RI pin
open/short.
Package
20-pin Small Outline Package (SOP)
October 2008
operation
and
versatile
interleave-switching
feature
decreased
to
reduce
power
PWM,
the
synchronized
slope
Packing
Eco Status
Method
Green
Tape & Reel
www.fairchildsemi.com

SG6905SZ Summary of contents

  • Page 1

    ... Temperature Range SG6905SY -40°C to +105°C For Fairchild’s definition of “green” Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Description The highly integrated SG6905 is specially designed for power supplies consisting of boost PFC and flyback PWM ...

  • Page 2

    ... Application Diagram © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Figure 1. Typical Application 2 www.fairchildsemi.com ...

  • Page 3

    ... Block Diagram © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Figure 2. Function Block Diagram 3 www.fairchildsemi.com ...

  • Page 4

    ... Marking Information Pin Configuration © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 F- Fairchild Logo Z- Plant Code X- Year Code Y- Week Code TT: Die-Run Code T: Package Type (S=SOP Green Package M: Manufacture Flow Code Figure 3. Marking Information Figure 4. Pin Configuration (Top View) 4 www.fairchildsemi.com ...

  • Page 5

    ... A large capacitor value results in a narrow bandwidth and hence improves the power factor. Input AC Current. Before startup, this input is used to provide startup current for V 20 IAC normal operation, this input is used to provide current reference for the multiplier. © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 ]KHz, where kΩ. For example ...

  • Page 6

    ... The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to absolute maximum ratings. Symbol T Operating Ambient Temperature A © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Parameter < 50°C A Parameter 6 Min ...

  • Page 7

    ... Protection Threshold (with T V Recovery Level on VRMS RMS-UVP-2 Under-Voltage-Protection Delay Time t UVP (No Delay for Startup) UVP Occurs, the Interval from PFC Off t D-PWM to PWM Off © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Conditions V =V – 0.16V DD DD-ON V =15V; OFC, DD OPWM open =24kΩ ...

  • Page 8

    ... Maximum Sink Current H Peak Current Limit Section I Constant Current Output P Peak Current Limit Threshold Voltage V PK Cycle-by-Cycle Limit (V t Propagation Delay PD-PFC t Leading-Edge Blanking Time LEB-PFC © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Conditions +1. =24kΩ =20+I *0. =24KΩ ...

  • Page 9

    ... DCY Maximum Duty Cycle MAX PFC On/Off Section I Constant Current Output for PFC_ON Pin ON/OFF V Turn-Off Threshold Voltage OFF t Debounce Time of PFC_On/Off PFC_ON © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Conditions Multiplier Range R =24kΩ =1.05V; RMS I =90µ =5V ...

  • Page 10

    ... Output-Voltage Low OL-PWM V Output-Voltage High OH-PWM t Rising Time r-pwm t Falling Time f-pwm Maximum Duty Cycle DCY MAXPWM © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Conditions R =24kΩ I PFC_ON > VOFF PFC_ON > VOFF = 20KHz PFC_ON > VOFF S Gate Turn Off PFC_ON < VOFF OZ ...

  • Page 11

    ... V OTP Threshold Voltage OTP-OFF t OTP Debounce Time otp Soft-Start Section I Constant Current Output for Soft-Start SS R Discharge R D DSon © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 Conditions and PFC_ON Low FBPFC=2V I =1mA SINK R =24kΩ =24kΩ I RT=24kΩ ...

  • Page 12

    ... The PFC stage is disabled, whenever the voltage at PFC_ON pin exceeds V 2. The RDY Pin is reset, whenever the voltage at PFC_ON pin exceeds V occur reaches V DD DD-MIN Green Mode Function Item PFC_ON PFC_OFF © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 PWM GATE No change OFF OFF No change No change No change OFF ...

  • Page 13

    ... Temperature(°C) Figure 8. V DD-ON 68.00 66.80 65.60 64.40 63.20 62.00 -40 -25 - Temperature(°C) Figure 10. © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 10.00 8.80 7.60 6.40 5.20 4. 110 125 vs 11.00 10.40 9.80 9.20 8.60 8. 110 125 vs ...

  • Page 14

    ... Temperature(°C) Figure 14. V 120.00 104.00 88.00 72.00 56.00 40.00 -40 -25 - Temperature(°C) Figure 16. t R-PFC © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 (Continued) 2.80 2.76 2.72 2.68 2.64 2. 110 125 vs. T FBPFC A 98.00 97.00 96.00 95.00 94.00 93 ...

  • Page 15

    ... Temperature(°C) Figure 20. t R-PWM 83.00 81.00 79.00 77.00 75.00 73.00 -40 -25 - Temperature(°C) Figure 22. DCY MAX-PWM © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 (Continued) 0.95 0.93 0.91 0.89 0.87 0. 110 125 -40 vs 120.00 102.00 84.00 66.00 48.00 30 ...

  • Page 16

    ... R can be large to reduce power consumption. One AC 10µF capacitor should hold enough energy for successful startup. After startup, S1 switches so that © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 the current I helps consumption. and ...

  • Page 17

    ... Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 There are two major concerns when compensating the voltage-loop transient response. Optimizing interaction between stability and transient response requires that the error amplifier’ ...

  • Page 18

    ... Figure 29. 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 © 2007 Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 To improve oscillation, a synchronized positive-going ramp is inserted at every switching cycle ...

  • Page 19

    ... Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’ ...

  • Page 20

    ... Fairchild Semiconductor Corporation SG6905 • Rev. 1.1.2 20 www.fairchildsemi.com ...