High Power Factor Flyback PWM Controller

FEATURES

◆   Built-in Soft Start

◆   Very Low Startup Current

◆   Under Voltage Lockout with 8V Hysteresis

◆   VCC Over Voltage Protection (OVP)

◆   Clear External EA Feedback Network before Power On

◆   Transition Mode (TM) Operation

◆   Highly Linear Analog Multiplier

◆   Proprietary “Frequency Adjusting” for Higher PF and Low THD

◆   3.3us Min. OFF Time

◆   270KHz Max Frequency Clamp

◆   Trimmed 1.5% Internal Voltage Reference

◆   Restart Timer for Stand-alone Applications

◆   Cycle-by-Cycle Current Limiting

◆   Built-in Leading Edge Blanking (LEB)

◆   Audio Noise Free Operation

◆   10V to 32V Wide Range of VCC Voltage

◆  800mA Drive Capability

APPLICATIONS

◆   LED Lighting Application

◆   Single Stage High PF Flyback AC/DC SMPS

GENERAL DESCRIPTION

SFL320 is a high power factor flyback PWM controller special for LED lighting applications. The IC adopts transition mode (TM) operation for high efficiency and low EMI. 

SFL320 will Clear External EA Feedback Network before IC power on. The IC also has Soft Start control to soften the stress on the MOSFET during power on period.

In SFL320, a highly linear analog multiplier is integrated to achieve low THD and high power factor. The zero current detector (ZCD) ensures TM operation. A restart timer is for stand alone applications. The IC also has the function of Min. OFF time and Max. Frequency Clamp to limits power MOS Vds spike when LED output is short.

In SFL320, the proprietary “Frequency Adjusting” can help to improve THD performance, while ensures audio noise free operation. A VCC Over Voltage Protection (VCC OVP) is integrated to improve system reliability.

SFL320 integrates functions and protections of Under Voltage Lockout (UVLO), VCC Over Voltage Protection (OVP), Soft Start Control, Cycle-by-cycle Current Limiting (OCP), GD Clamping, VCC Clamping, Leading Edge Blanking (LEB), etc.

In SFL320, VCC OVP is auto-recovery mode protection.

SFL320 is available in SOP-8 and DIP-8 packages.