Dialog expands Rapid Charge portfolio with AC/DC controller
Pump Express Plus is MediaTek’s proprietary fast charge protocol that supports high power chargers with an output of 15 W or more and reduces typical mobile device recharge times by up to 50%. The iW1788 follows Dialog’s recent introduction of its iW1680 Pump Express-compatible, 5 W/7.5 W AC/DC controller in March 2014.
The iW1788 is a single-chip adapter solution that reduces charge times in USB AC/DC wall chargers for high battery capacity smartphones and tablets. The device uses Dialog’s built-in, intelligent rapid charge digital algorithm to detect commands from smartphones and tablets designed with MediaTek’s Pump Express Plus-compatible MT6595 octa-core 4G LTE processors. The high power Pump Express Plus protocol enables the phone or tablet to request voltages as high as 12 V from the power adapter to provide safe and reliable power transfer at 15 W or more. This reduces charge times through more efficient power transfer to the battery.
Built on Dialog’s latest PrimAccurate primary-side controller topology, the iW1788 Rapid Charge AC/DC controller embeds sophisticated digital analysis on the primary side of the isolated power supply within the charger, eliminating the need for intelligence on the secondary side. PrimAccurate primary-side feedback also eliminates the need for a secondary-side regulator and opto-isolator for a simple, low component count solution.
The iW1788 supports power adapters up to 15 W, with high active average efficiency, low no-load power consumption less than 30 mW, and a low cost bill of materials. This provides a high power density solution that supports fast charging for higher capacity smartphone and tablet batteries without increasing the size of the adapter. The high efficiency also helps ensure that specified thermal requirements for the adapter case are not exceeded. Communication between the phone and iW1788 is through the VBUS supply line. The iW1788 digitally manages voltage scaling on the primary side of the transformer in the AC/DC adapter by analyzing the signal on the VBUS and scaling its output voltage accordingly from 3.6 V to 12 V. The iW1788 also offers a full array of protection
features including overvoltage, short circuit and over-temperature protection.The iW1788 comes in a standard 8-pin SOIC package. Full protection features include built-in output short-circuit, output overvoltage, output over-current and current-sense-resistor-short fault protection.
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