Secondary side technology targets white goods market

18th September 2015

Caroline Hayes

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Using the magnetic inductive coupling principle, Power Integrations has introduced the InnoSwitch-EP family of off-line CV/CC flyback switching ICs and shifts focus from the charger market to the white goods market where reliability is expected to be 1pmm.

The 725V InnoSwitch-EP (the EP stands for embedded power) ICs have an integrated 725V MOSFET, synchronous rectification and precise secondary-side feedback sensing control for multi-output, cross-regulation with full line protection and instantaneous transient response with less than 10mW no load consumption.

FluxLink technology produces efficient, reliable power supply circuits without an optocoupler for auxiliary and standby power, making the ICs suitable for use in appliances, HVAC, consumer electronics, computing, telecomms and datacomms.

According to the company, the ICs improve power supply efficiency from standby to full load to reduce system power consumption in all operational modes and represents a new tool to address Total Energy Consumption (TEC) regulations.

FluxLink enables high-performance secondary-side control to be delivered with the low component count usually associated with primary-side regulation. Efficient synchronous rectification technology can therefore be employed to deliver efficiency across the full load range, including heavy loads. For example, the ICs enable 20W power supplies to achieve approximately 90% efficiency in a multi-output design (which are an important feature in white good designs which can combine screens, clocks and regulators), while minimising no load consumption to less than 30mW. Line over-voltage regulation is highly accurate at ±5 %, while ±5 % over current protection regulation is also achieved.

Eliminating opto-couplers not only reduces the bill of materials but also benefits reliability, as they can degrade with time. Low voltage-drop across the synchronous rectifier FETs ensures highly accurate cross regulation between output voltage rails, potentially eliminating second stage linear regulators, saving both cost and wasted energy, says the company. This makes them suitable for appliances such as microwaves, washers and dryers, as well as stand-by power supplies for PC/server, air conditioning systems, displays, TVs, and smart lighting ballasts.