VIPER25 Off-line high voltage converters Features 800 V avalanche rugged power section Quasi-resonant (QR) control for valley switching operation SO16 narrow DIP-7 SO-16 Standby power < 50 mW at 265 Vac Limiting current with adjustable set point Description Adjustable and accurate overvoltage protection The device is an off-line converter with an 800 V rugged power section, a PWM control, double On-board soft-start levels of overcurrent protection, overvoltage and Safe auto-restart after a fault condition overload protections, hysteretic thermal Hysteretic thermal shutdown protection, soft-start and safe auto-restart after any fault condition removal. Burst mode operation and device very low consumption helps to meet Applications the standby energy saving regulations. The quasi- Adapters for PDA, camcorders, shavers, resonant feature reduces EMI filter cost. Brown- cellular phones, cordless phones, videogames out and brown-in function protects the switch mode power supply when the rectified input Auxiliary power supply for LCD/PDP TV, voltage level is below the normal minimum level monitors, audio systems, computer, industrial specified for the system. The high voltage start-up systems, LED driver, No el-cap LED driver, circuit is embedded in the device. utility power meter SMPS for set-top boxes, DVD players and Figure 1. Typical topology recorders, white goods QSX & , W 9 R W O J D H X W 2 & SX W 9 R W O J D H 1 , 5 ) 0%2 6 =& 9 - V Table 1. Device summary Order codes Package Packaging VIPER25LN / VIPER25HN DIP-7 Tube VIPER25HD / VIPER25LD Tube SO16 narrow VIPER25HDTR / VIPER25LDTR Tape and reel July 2010 Doc ID 15585 Rev 4 1/40 www.st.com 40 )% *1 %5Contents VIPER25 Contents 1 Block diagram 4 2 Typical power . 4 3 Pin settings 5 4 Electrical data 6 4.1 Maximum ratings 6 4.2 Thermal data . 6 4.3 Electrical characteristics . 7 5 Typical electrical characteristics 11 6 Typical circuits 14 7 Operation description . 15 7.1 Power section and gate driver . 15 7.2 High voltage startup generator . 15 7.3 Power-up description 16 7.4 Power-down description 19 7.5 Auto-restart description 19 7.6 Quasi-resonant operation . 20 7.7 Frequency foldback function and valley skipping mode 22 7.8 Double blanking time 23 7.9 Starter . 24 7.10 Current limit set point and feed-forward option . 24 7.11 Overvoltage protection (OVP) . 26 7.12 Summary on ZCD pin 28 7.13 Feedback and overload protection (OLP) . 28 7.14 Burst-mode operation at no load or very light load 32 7.15 Brown-out protection 32 7.16 2nd level over current protection and hiccup mode . 34 2/40 Doc ID 15585 Rev 4