A 94% efficient offline flyback switcher IC

InnoSwitch3 devices are well suited for power supplies with challenging energy consumption, footprint or thermal constraints, particularly those targeting mandatory Total Energy Consumption (TEC) specifications.

The InnoSwitch3 IC family is optimised into three application specific series:

• CE: Current External. Includes accurate CC/CV regulation with external output current sense for optimum design flexibility. Targets compact single-voltage chargers, adapters, IoT and building automation.
• CP: Constant Power. Well suited for USB Power Delivery (PD), rapid charging and other applications where a dynamic output voltage is required.
• EP: Embedded Power. Features the family’s highest rated MOSFET (725V) and provides full line and load protection with excellent multi-output cross regulation for demanding industrial applications and appliances.

These newest flyback switcher ICs employ Power Integrations’ isolated digital communications technology, FluxLink, plus synchronous rectification, quasi-resonant switching and a precise secondary-side feedback sensing and control circuit. This results in highly efficient, accurate, reliable power supply circuits without the need for optocouplers. InnoSwitch3 devices are CCC, UL and VDE safety certified to bridge the isolation barrier, and the InSOP-24 package provides a low profile, thermally efficient solution with extended 11.5mm creepage and clearance between primary and secondary sides for high reliability, surge and ESD robustness. The new devices also incorporate a host of protection features, including lossless line overvoltage and under voltage, output overvoltage, over power, over current and over temperature protection, as well as output rectifier short circuit protection. Device sub-families are provided with either latching or auto-recovery capability, according to the typical demands of each target application space. All InnoSwitch3 ICs feature on-board high voltage MOSFETs (rated at 650V for the CP and CE series and 725V for the EP series).

Mike Matthews, VP of product development at Power Integrations commented: “InnoSwitch3 ICs represent a new state of the art in flyback power supply design. These new devices surpass the previously unrivaled efficiency of our InnoSwitch products, reducing losses by a further 25% and delivering the highest available efficiency across all line and load conditions. With unmatched system simplicity and low component count, InnoSwitch3 ICs enable exceptionally compact, reliable power supplies for a vast range of applications.”

Andy Smith, Power Integrations added: “Efficiency is becoming increasingly important. Efficiency is the difference between input power and output power and describes how much of the power going in is lost as heat. The bigger an object is, the better able it is to radiate this heat away. So if you want to make things smaller, you have to become more efficient.

“One way of achieving this is to add heatsinks. These have been around in power supplies for a long time and although they are very effective at increasing the surface area of a devices and spreading heat around so you don’t get hotspots, they are expensive and they add a lot of size. So by increasing efficiency you can reduce the need for heatsinks.”