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Technical content
©SiFirst Technology - 1 - Confidential SiFirst_DS_1530_V1.2 SF1530
FEATURES
◆ Proprietary “Zero OCP/OPP Recovery Gap” Control ◆ Built-in Soft Start Function ◆ 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 line input is compensated. The IC has built-in synchronized slope compensation to prevent sub-harmonic oscillation at high PWM duty output. The IC also has built-in soft start function to soften the stress on the MOSFET during power on period. SF1530 integrates functions and protections of Under Voltage Lockout (UVLO), VCC Over Voltage Protection (OVP), Cycle-by-cycle Current Limiting (OCP), Pins Floating Protection, Over Load Protection (OLP), RT Pin Short-to-GND Protection, Gate Clamping, VCC Clamping, Leading Edge Blanking (LEB). SF1530 is available in SOT23-6, DIP-8 packages. TYPICAL APPLICATION AC IN RT VDD GATE GND FB SF1530 DC Out CS 5 46 TL431 High Performance Current Mode PWM Controller SiFirst Confidential
©SiFirst Technology - 2 - Confidential SiFirst_DS_1530_V1.2 SF1530 Pin Configuration GND FB 4RT GATE VDD CS SOT23-6 GATE VDD 3NC GND FB NC DIP8 5CS RT
Ordering Information
Part Number Top Mark Package Tape & Reel SF1530LGT .30YWW SOT26 Green Yes SF1530DP SF1530DP DIP8 RoHS Marking Information 3 0 Y W W Dot: Pin1 Mark 30:Part number SF1530 YWW: Year&Week Code YWW: Year&Week code SiFirst Confidential