SF5879
HV-mWTM、2nd Generation Quasi-Resonant (QR-IITM ) PWM Power Switch
FEATURES
◆ Meet EPS Level 6
◆ Built-in 600V Power MOSFET
◆ Proprietary QR-IITM Technology:
●Digital Anti-jitter for Audio Noise Free
Operation
● Digital Frequency Foldback
● Digital Frequency Jittering
◆ Proprietary HV-mWTM to Achieve Less than
80mW Standby Power
◆ Multi-Mode Operation for High Efficiency
◆ 12.7us Maximum On Time
◆ 80KHz Maximum Frequency Limit
◆ 53KHz Frequency Low Clamping in QR Mode
◆ Maximum 65% Duty Cycle
◆ Adaptive Slope Compensation for CCM Mode
◆ Built-in Soft Start Function
◆ Built-in Synchronous Slope Compensation
◆ Cycle-by-Cycle Current Limiting
◆ Leading Edge Blanking (LEB)
◆ Constant Power Limiting
◆ VDD UVLO, OVP & Clamp
APPLICATIONS
Offline AC/DC Flyback Converter for
◆ AC/DC Adaptors
◆ SMPS Power Supply
GENERAL DESCRIPTION
SF5879 is a high performance, 2nd Generation Quasi-
Resonant (QR-IITM) PWM power switch for offline
flyback power converter applications. The built-in
proprietary HV-mWTM technology and QR-IITM
technology with high level protection features can
improve the SMPS reliability and performance.
In SF5879, the “Digital Anti-Jitter” function can
automatically select and lock a valley at a given
loading, which can achieve audio noise free
operation. On the other hand, the “Digital Frequency
Jittering” function makes the system have superior
EMI performance than conventional QR system.
SF5879 is a multi mode controller. When full loadings,
the IC works in CCM mode or QR mode based on the
AC line input. When the loading goes low, the IC
enters into “Digital Frequency Foldback” mode to
boost power conversion efficiency. When the output
power is very small, the IC enters into burst mode
and can achieve less than 80mW no load power.
SF5879 integrates functions and protections of Under
Voltage Lockout (UVLO), VDD Over Voltage
Protection (VDD OVP), Output Over Voltage
Protection (Output OVP), Cycle-by-cycle Current
Limiting (OCP), Pin Floating Protection, Over Load
Protection (OLP), Soft Start, VCC Clamping, etc. In
SF5879, the protections are auto-recovery mode.
SF5879 is available in DIP8 package.
TYPICAL APPLICATION
EMI
Filter
DC Out
SF5879
1 DEM VDD 8
2 FB VDD 7
3 GND Drain 6
4 CS Drain 5
©SiFirst Technology
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TL431
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SiFirst_DS_5879_V1.0
