Document
FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation
April 2009
FSQ0765RQ Green-Mode Fairchild Power Switch (FPS™) for Quasi-Resonant Operation - Low EMI and High Efficiency
Features
! Optimized for Quasi-Resonant Converter (QRC) ! Low EMI through Variable Frequency Control and AVS
Description
A Quasi-Resonant Converter (QRC) generally shows lower EMI and higher power conversion efficiency than a conventional hard-switched converter with a fixed switching frequency. The FSQ-series is an integrated Pulse-Width Modulation (PWM) controller and SenseFET specifically designed for quasi-resonant operation and Alternating Valley Switching (AVS). The PWM controller includes an integrated fixed-frequency oscillator, Under-Voltage Lockout (UVLO), LeadingEdge Blanking (LEB), optimized gate driver, internal softstart, temperature-compensated precise current sources for a loop compensation, and self-protection circuitry. Compared with a discrete MOSFET and PWM controller solution, the FSQ-series can reduce total cost, component count, size, and weight; while simultaneously increasing efficiency, productivity, and system reliability. This device provides a basic platform that is well suited for cost-effective designs of quasi-resonant switching flyback converters.
(Alternating Valley Switching)
! High-Efficiency through Minimum Voltage Switching ! Narrow Frequency Variation Range over Wide Load
and Input Voltage Variation Power Consumption
! Advanced Burst-Mode Operation for Low Standby ! Simple Scheme for Sync Voltage Detection ! Pulse-by-Pulse Current Limit ! Various Protection functions: Overload Protection
! ! ! !
(OLP), Over-Voltage Protection (OVP), Abnormal Over-Current Protection (AOCP), Internal Thermal Shutdown (TSD) with Hysteresis, Output Short Protection (OSP) Under-Voltage Lockout (UVLO) with Hysteresis Internal Startup Circuit Internal High-Voltage Sense FET (650V) Built-in Soft-Start (17.5ms)
Applications
! Power Supply for LCD TV and Monitor, VCR, SVR,
STB, and DVD & DVD Recorder
! Adapter
Related Resources
Visit http://www.fairchildsemi.com/apnotes/ for:
! AN-4134: Design Guidelines for Offline Forward ! !
! ! ! !
!
Converters Using Fairchild Power Switch (FPS™) AN-4137: Design Guidelines for Offline Flyback Converters Using Fairchild Power Switch (FPS™) AN-4140: Transformer Design Consideration for Offline Flyback Converters Using Fairchild Power Switch (FPS™) AN-4141: Troubleshooting and Design Tips for Fairchild Power Switch (FPS™) Flyback Applications AN-4145: Electromagnetic Compatibility for Power Converters AN-4147: Design Guidelines for RCD Snubber of Flyback AN-4148: Audible Noise Reduction Techniques for Fairchild Power Switch Fairchild Power Switch(FPS™) Applications AN-4150: Design Guidelines for Flyback Converters Using FSQ-Series Fairchild Power Switch (FPS™)
© 2008 Fairchild Semiconductor Corporation FSQ0765RQ Rev. 1.0.1
www.fairchildsemi.com
Free Datasheet http://www.datasheet4u.com/
FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation
Ordering Information
Maximum Output Power(1) Product Number PKG.(5) Operating Temp. Current RDS(ON) Limit Max. 230VAC±15%(2) Adapter(3)
80W
85-265VAC Adapter(3)
48W
Open Frame(4)
90W
Open Frame(4)
70W
Replaces Devices
FSCM0765R FSDM0765RB
FSQ0765RQWDTU TO-220F-6L -25 to +85°C
3.5A
1.6Ω
Notes: 1. The junction temperature can limit the maximum output power. 2. 230VAC or 100/115VAC with doubler. 3. Typical continuous power in a non-ventilated enclosed adapter measured at 50°C ambient temperature. 4. Maximum practical continuous power in an open-frame design at 50°C ambient. 5. For Fairchild’s definition of “green” Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. Eco Status: RoHS.
© 2008 Fairchild Semiconductor Corporation FSQ0765RQ Rev. 1.0.1 2
www.fairchildsemi.com
Free Datasheet http://www.datasheet4u.com/
FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation
Application Diagram
VO
AC IN Vstr PWM FB VCC Drain
Sync
GND
FSQ0765R Rev.00
Figure 1. Typical Flyback Application
Internal Block Diagram
Sync 5 Vstr 6 VCC 3 Drain 1
AVS
0.35/0.55 VBurst IFB 3R R tON < tOSP after SS SoftStart
OSC
Vref
VCC
Vref Idelay
VCC good 8V/12V
FB 4
PWM LEB 250ns
S Q R Q Gate driver
VOSP
LPF AOCP
VSD LPF VOVP
TSD
S
Q
2
VOCP (1.1V)
GND
R Q
VCC good FSQ0765R Rev.00
Figure 2. Internal Block Diagram
© 2008 Fairchild Semiconductor Corporation FSQ0765RQ Rev. 1.0.1 3
www.fairchildsemi.com
Free Datasheet http://www.datasheet4u.com/
FSQ0765RQ — Green-Mode Farichild Power Switch (FPS™) for Quasi-Resonant Operation
Pin Configuration
6. Vstr 5. Sync 4. FB 3. VCC 2. GND 1. Drain
FSQ0765R Rev.00
Figure 3. Pin Configuration (Top View)
Pin Definitions
Pin #
1 2 3
Name
Drain GND VCC
Description
SenseFET drain. High-voltage power SenseFET drain connection. Ground. This pin is the control ground and the SenseFE.