STEVAL-ISA022V1 STMicroelectronics

VIPER12A-E Low power offline switched-mode power supply primary switcher Features Fixed 60 kHz switching frequency 9 V to 38 V wide range V voltage DD Current mode control Auxiliary undervoltage lockout with hysteresis SO-8 DIP-8 High voltage start-up current source Overtemperature, overcurrent and overvoltage Typical applications cover off line power supplies protection with auto-restart for battery charger adapters, standby power Typical power capability supplies for TV or monitors, auxiliary supplies for motor control, etc. European (195 - 265 Vac) 8 W for SO-8, 13 W for DIP-8 The internal control circuit offers the following European (85 - 265 Vac) 5 W for SO-8, benefits: Large input voltage range on the V pin DD 8 W for DIP-8 accommodates changes in auxiliary supply voltage (This feature is well adapted to battery charger adapter configurations), automatic burst Description mode in low load condition and overvoltage The VIPER12A combines a dedicated current protection in HICCUP mode. mode PWM controller with a high voltage power MOSFET on the same silicon chip. Figure 1. Block diagram DRAIN ON/OFF 60kHz OSCILLATOR REGULATOR PWM INTERNAL S LATCH SUPPLY OVERTEMP. FF R1 Q DETECTOR R2 R3 R4 VDD + BLANKING 8/14.5V 0.23 V + OVERVOLTAGE LATCH R 230 + FF S Q 42V 1 k FB SOURCE December 2010 Doc ID 11977 Rev 2 1/21 www.st.com 21Contents VIPER12A-E Contents 1 Electrical data 3 1.1 Maximum rating . 3 1.2 Thermal data . 3 2 Electrical characteristics . 4 3 Pin connections and function . 6 4 Rectangular U-I output characteristics 7 5 Wide range of VDD voltage . 8 6 Feedback pin principle of operation 9 7 Startup sequence 11 8 Overvoltage threshold 12 9 Operation pictures . 13 10 Package mechanical data 16 11 Order codes . 19 12 Revision history . 20 2/21 Doc ID 11977 Rev 2