SF1530

SF1530 High Performance Current Mode PWM Controller FEATURES ◆ Proprietary “Zero OCP/OPP Recovery Gap” Control ◆ Built-in Soft Start Function ◆ All Pins Floating Protection ◆ Very Low Startup Current ◆ High Voltage CMOS Process with Excellent ESD Protection ◆ Frequency Reduction and Burst Mode Control for Energy Saving ◆ Current Mode Control ◆ Built-in Frequency Shuffling ◆ Programmable Switching Frequency ◆ Built-in Synchronous Slope Compensation ◆ Cycle-by-Cycle Current Limiting ◆ Built-in Leading Edge Blanking (LEB) ◆ Constant Power Limiting ◆ Audio Noise Free Operation ◆ VDD OVP & Clamp ◆ VDD Under Voltage Lockout (UVLO) APPLICATIONS Offline AC/DC Flyback Converter for ◆ AC/DC Adaptors ◆ Open-frame SMPS ◆ Set-Top Box Power Supplies ◆ ATX Standby Power GENERAL DESCRIPTION SF1530 is a high performance, low cost, highly integrated current mode PWM controller for offline flyback converter applications. PWM switching frequency with shuffling is externally programmable, which can reduce conduction EMI emission of a power supply. When the output power demands decrease, the IC automatically decreases switching frequency for high power conversion efficiency. When the current set-point falls below a given value, e.g. the output power demand diminishes, the IC enters into burst mode and provides excellent efficiency without audio noise. The IC can achieve “Zero OCP/OPP Recovery Gap” using SiFirst’s proprietary control algorithm. Meanwhile, the OCP/OPP variation versus universal l...