Swiss firm ST Microelectronics has introduced off-line high-voltage converters for consumer and lighting use in smart-home applications.

The Viper 11B converters make tiny, efficient and low-cost power supplies for applications up to 8W, including lighting, smart-home equipment, appliances and smart meters.

The converters can cut the bill of materials through feature integration to simplify circuit design and save external components. The 800V avalanche-rugged MOSFET requires only small snubbing components and a built-in SenseFET provides almost lossless current sensing with no additional resistors.

High-voltage start-up circuitry is on-chip, requiring only an external capacitor for the V_cc supply, and the frequency-jittered oscillator reduces any external filtering needed to meet electromagnetic compatibility (EMC) regulations.

Also, being housed in a compact SSOP10 package, the converters deliver power where space is tight. This can be valuable in applications that are subject to rigidly defined form factors, such as LED-lighting drivers and smart bulbs. The converters also help meet stringent eco-design regulations, with low standby current that cuts no-load power consumption to less than 10mW and pulse-skipping operation to boost light-load efficiency.

Flexibility is another strength, with a wide V_cc range that permits supplying the converter from a transformer auxiliary winding or from the output in a non-isolated topology. They can be used in non-isolated flyback, buck and buck-boost topologies and isolated flyback with primary-side or secondary-side regulation.

Featuring output overload and overvoltage protection with automatic restart, V_cc clamping, thermal shutdown and soft-start, the Viper 11B converters (www.st.com/viper11b) help designers build strong and reliable power supplies. Two variants are available, letting designers select the Viper 113B with drain-current protection threshold of 370mA or the 114B that has a current limit of 480mA.

The converters are in production now, priced from $0.56 for orders of 1000 pieces.