by 
London, UK - Dialog Semiconductor plc has entered the white goods sector with the launch of two power control integrated circuits that address reliability while reducing bill-of-materials (BOM) costs without compromising power supply performance. The expanded power conversion portfolio now includes AC/DC AccuSwitch PWM controllers that use primary-side regulation to eliminate the need for optocouplers, while still providing accurate voltage cross-regulation.
The household appliance market is growing at 3.8 percent annually and is forecast to reach 430 million units by 2017, according to the Freedonia Group.
“Most appliances today use secondary-side control to maintain the tight output voltage regulation for stable operation in multi-rail systems. For example, a 5-V output for the system microcontroller (MCU) needs ±5% voltage accuracy, while 12-V to 16-V rails for motor or relay control require ±10% accuracy,” said Dialog. “However, secondary-side designs require optocouplers, which have significantly worse failure rates compared to other components in the power supply.”
The new iW1818 and iW1830 AccuSwitch pulse width modulation (PWM) controllers use Dialog’s PrimAccurate primary-side control to eliminate the need for optocouplers. In addition to reducing BOM costs and eliminating the optocoupler, the new devices also deliver fewer solder joints for potential failure, which inherently increases reliability, said Dialog.
However, there is a common believe in the industry that primary-side regulation comes at the expense of voltage cross-regulation accuracy, said Davin Lee, senior vice president and general manager of the Power Conversion Business Group at Dialog Semiconductor, in a statement.
Dialog’s response to the issue is its patented intelligent digital control loop technology that is said to provide accurate voltage cross-regulation between the multiple power rails in the system, while providing the higher reliability associated with the primary-side design.
The iW1818 and iW1830 devices simplify appliance power supply designs by integrating a high-voltage power switch (800V BJT and 700V MOSFET, respectively) and support high capacitance loads (up to 6,000 µF) at up to 12V. In addition, the adaptive multi-mode PWM/PFM control in the iW1818 and iW1830 dynamically changes the switching frequency to optimize the system for high efficiency even at light loads, said Dialog.
Key specs include: >80% active average efficiency, high efficiency at loads as light as 10% and <50 mW no-load standby power with fast standby recovery time. “This helps white goods designers meet global energy efficiency regulations, including the European Ecodesign Directive and the U.S. Department of Energy (DoE) energy conservation standards,” said Dialog.
Both parts come in a thermally efficient, small footprint PDIP-7 package. The parts also feature built-in over-temperature protection, and offer full protection from fault conditions, such as output short-circuit, over-voltage and over-current.
Applications for the new digital controllers include dishwashers, refrigerators, cooking ranges, microwaves and other high-volume appliance applications.
