Flyback switcher ICs target ultra-compact mobile chargers

Power Integrations has launched the InnoSwitch4-CZ family of high frequency, zero voltage switching (ZVS) flyback switcher ICs. The InnoSwitch4-CZ devices incorporate a 750-V primary switch using the company’s PowiGaN technology and a novel high frequency active clamp flyback controller to enable a new class of ultra-compact and ultra-efficient chargers for phones, tablets, and laptops.

InnoSwitch4-CZ flyback switcher IC (Image: Power Integrations)

The InnoSwitch4-CZ family incorporates 750-V switch, primary, and secondary controllers, a ClampZero interface, synchronous rectification, and safety-rated feedback in a single, compact InSOP-24D package. A steady state switching frequency of up to 140 kHz minimizes transformer size, which further increases power density, said Power Integrations.

The InnoSwitch4-CZ and ClampZero combination provides up to 95% efficiency and maintains very high efficiency across variations in line voltage, system load, and output voltage in comparison with older active clamp flyback approaches, said the company. This is thanks to variable frequency asymmetrical control of the active clamp with intelligent ZVS, which enables both discontinuous and continuous conduction modes of operation.

The flyback switcher ICs target high efficiency compact USB PD adapters, high-density flyback designs up to 110 W, and high-efficiency CV/CC power supplies They are said to offer exceptional CV/CC accuracy, independent of external components, and to consume less than 30 mW no-load including line-sensing safety and protection features. They feature auto-restart or latching fault response for output over-voltage and under-voltage protection, multiple output under-voltage fault thresholds and latching or hysteretic primary over-temperature protection.

InnoSwitch4-CZ schematic (Image: Power Integrations)

One of the first devices to use the InnoSwitch4-CZ devices is the Anker Nano II chargers. These 65-W, 45-W, and 30-watt (w) devices deliver smaller and faster charging options for consumer devices. These chargers measure 41.72 × 36 × 44 mm, 37.72 × 35 × 41 mm, and 31.54 × 30.39 × 37.85 mm, respectively.

Anker Nano II series chargers (Image: Anker)

The InnoSwitch4-CZ ICs are priced at $3.85 each in quantities of 10,000. A technical overview video of the InnoSwitch4-CZ and ClampZero devices is available here.