The SF5785 is a high-performance, 2-neodymium quasi-resonant (QR-II™ series) PWM switch intended for offline flyback power converter applications. The proprietary QR-II™ series technology built into the SF5785 incorporates advanced protection features that enhance the reliability and performance of the SMPS. The "digital anti-jitter" function in the SF5785 automatically selects and locks the valley point under a given load, enabling audio-noise-free operation. Conversely, the "digital frequency jitter" function provides the system with superior EMI performance compared to traditional QR systems. The SF5785 is a multi-mode controller. At full load, the IC operates in CCM or QR mode depending on the AC line input. When the load decreases, the IC enters "digital frequency foldback" mode to improve power conversion efficiency. When the output power is very low, the IC enters burst mode, achieving no-load power less than 75mW. The SF5785 integrates features and protections such as undervoltage lockout (UVLO), VCC overvoltage protection (OVP), output overvoltage protection (OVP), cycle-by-cycle current limit (OCP), pin float protection, overload protection (OLP), AC power-down protection, soft start, VCC clamping, and gate clamping. The SF5785's protection functions are auto-recovery mode protections. The SF5785 is available in a DIP-8 package.

◆   Compliant with EPS Level 6

◆   AC undervoltage protection (BOP)

◆   Built-in 650V power MOSFET

◆   Proprietary QR-II type ^{TM series} Technology:

● Digital anti-jitter, enabling noise-free audio operation

● Digital frequency foldback

● Digital frequency jitter, providing better EMI

◆   Standby power consumption less than 75mW

◆   Multi-mode operation, high efficiency

◆   12.7us maximum on-time

◆   80KHz maximum frequency limit

◆   52KHz low frequency clamping in QR mode

◆   65% maximum duty cycle

◆   CCM mode adaptive slope compensation

◆   Built-in soft-start function

◆   Pin floating protection

◆   Built-in synchronous slope compensation

◆   Cycle-by-cycle current limit

◆   Leading edge blanking (LEB)

◆   Constant power limit

◆   VDD UVLO, OVP and Clamp