New switcher ICs deliver high accuracy in non-isolated off-line applications

Power Integrations has introduced its LinkSwitch-TN2 off-line switcher IC for non-isolated applications with up to 360mA output current. The new device, which may be configured as a buck, buck-boost or a non-isolated flyback converter, delivers high accuracy, high efficiency and excellent no-load performance. The device incorporates new safety features including input over- and under-voltage protection and a rugged MOSFET with a 725V breakdown voltage, offering robust output short-circuit and over-temperature protection against line surges and swells. Applications include appliances, HVAC, industrial, home automation (IOT) and metering systems, particularly those destined for India and other geographies with challenging power grid stability. The ICs feature voltage regulation of better than -/+3%. This high level of accuracy allows designers to eliminate post regulators, minimizing the BOM, increasing efficiency and reducing size. The new IC requires just 20 additional components to complete a buck converter, and may be configured to use off-the-shelf inductors, further reducing cost and supply chain complexity. The new devices are very efficient in low-power applications – above 80% in 12V, 120mA (1.4W) buck designs for example. The designs typically provide excellent efficiency across the entire load range while consuming less than 30mW no-load in a buck arrangement and less than 10mW when configured as a non-isolated flyback. This is a key tool for designers addressing TEC regulations, which prescribe an energy budget limit over a range of operating modes. LinkSwitch-TN2 efficiency performance enables manufacturers to design power supplies to meet worldwide product energy-efficiency requirements from the U.S. DOE, European Commission ErP Ecodesign Directive, California Energy Commission, ENERGY STAR, and others. Comments senior product marketing manager, Silvestro Fimiani: “Our LinkSwitch-TN2 off-line converter ICs include a selectable cycle-by-cycle current limit which allows designers to choose low-cost inductors and capacitors saving cost and board space, or configure the circuit to output higher power using optimized exernal components. The new device’s robust 725 V MOSFET allows a typical design to easily withstand 1 kV differential line surges without additional surge suppressors.”