VIPER31 Datasheet Energy saving offline high voltage converter Features 800 V avalanche-rugged power MOSFET to cover ultra-wide VAC input range Embedded HV startup and sense FET Current mode PWM controller Drain current limit protection (OCP): 710 mA (VIPER317) ~ AC D IN R IN 850 mA (VIPER318) VCC DRAIN 990 mA (VIPER319) OVP VIPER31 CONTROL FB Wide supply voltage range: 4.5 V to 30 V COMP UVP GND C IN D < 20 mW 230 V in no-load AUX AC R1 < 430 mW 230 V , 25 0mW output load C1 AC C2 R2 D2 C3 L OUT VOUT Jittered switching frequency reduces the EMI filter cost: D1 COUT GND 30 kHz 7% (type X) GND 60 kHz 7% (type L) 132 kHz 7% (type H) Embedded E/A with 1.2 V reference Built-in soft-start for improved system reliability Protections with automatic restart: overload/short-circuit (OLP) thermal shutdown overvoltage Product status link Protections without automatic restart: VIPER31 pulse-skip protection to avoid flux runaway undervoltage/disable Product label max. duty cycle Application Low power SMPS for home appliances, home automation, industrial, consumers, lighting Low power adapters Description The VIPER31 device is a high-voltage converter that smartly integrates an 800 V avalanche rugged power MOSFET with PWM current-mode control. The 800 V breakdown allows extended input voltage range to be applied, as well as to reduce the size of the DRAIN snubber circuit. The IC can meet the most stringent energy- saving standards as it has very low consumption and operates in pulse frequency modulation at light load. Overvoltage and undervoltage protections with separate and settable intervention thresholds are available at OVP and UVP pins respectively. UVP can also be used as a disabling input for the entire SMPS, with ultra-low residual input power consumption. Integrated HV startup, sense FET, error amplifier and oscillator with frequency jitter allow a complete application to be designed with a minimum component count. Flyback, buck and buck boost topologies are supported. DS13285 - Rev 3 - November 2020 www.st.com For further information contact your local STMicroelectronics sales office.VIPER31 Pin setting 1 Pin setting Figure 1. Connection diagram GND DRAIN N.C. DRAIN DRAIN VCC N. A. DRAIN N. C. UVP N. C. OVP FB N. C. N. C. COMP Table 1. Pin description Pin Name Function number Ground and MOSFET source. Connection of both the source of the internal MOSFET and the return of 1 GND the bias current of the device. All of the groundings of bias components must be tied to a trace going to this pin and kept separate from the pulsed current return. 2 N. C. Not connected. When designing the PCB, this pin can be soldered to GND. Controller Supply. An external storage capacitor has to be connected across this pin and GND. The pin, internally connected to the high-voltage current source, provides the VCC capacitor charging current 3 VCC at startup. A small bypass capacitor (0.1 F typ.) in parallel, placed as close as possible to the IC, is also recommended, for noise filtering purposes. Not available for user. This pin is mechanically connected to the controller die pad of the frame. In order 4 N.A. to improve noise immunity, it is highly recommended to connect it to GND. Undervoltage Protection. If V falls below the internal threshold V (0.4 V typ.) for more than UVP UVP th t time (30 ms, typ.), the IC is disabled, and its consumption reduced to ultra-low values. When UVP DEB V rises above V the device waits for a t time interval (30 ms, typ.) then resumes UVP UVP th, UVP REST 5 UVP switching. The pin can be used to realize an input undervoltage protection or as a disabling input for the entire SMPS, with ultra-low residual input power consumption. If the feature is not required, the pin must be left open, which excludes the function. Overvoltage protection. If VOVP exceeds the internal threshold V (4 V typ.) for more than OVP th t time (250 sec, typ.), the PWM is disabled in auto-restart for t (500 msec, typ.) until OVP DEB OVP REST the OVP condition is removed, after that it restarts switching with soft-start phase. OVP pin can be 6 OVP used to realize an input overvoltage protection (or, in non-isolated topologies, an output overvoltage protection). If the feature is not required, the pin must be connected to GND, which excludes the function. Direct feedback. It is the inverting input of the internal transconductance E/A, internally referenced to 1.2 V with respect to GND. In non-isolated converter, the output voltage information is directly fed into the 7 FB pin through a voltage divider. In primary regulation, the FB voltage divider is connected to the VCC. The E/A is disabled if FB is connected to GND pin. DS13285 - Rev 3 page 2/40