AC/DC adapter interface IC can reach efficiency up to 88%

The new IC can reach efficiency as high as 88%, and this efficiency enables the higher power density needed for smaller form-factor fast charging adapters. The IC can dleiver this efficiency without the need for a synchronous rectifier as required by competing solutions. For the ultimate in high power density and small form factor, Dialog’s Quick Charge 2.0 rapid charge solution can be used with a synchronous rectifier to provide even higher efficiency up to 88%.

The iW620 interface IC detects commands from the Quick Charge 2.0-enabled mobile device via the USB cable, then communicates with the iW1760 PWM primary-side controller and configures the power adapter output voltage. Quick Charge 2.0 is a proprietary protocol from Qualcomm for charging smartphones, tablets and other mobile devices up to 75% faster than conventional USB charging technology.

Current sensing is performed by the iW1760 on the primary side, which eliminates the need for a secondary-side current sense resistor. This enables an inherently more efficient solution than competing Quick Charge 2.0 wall charger approaches. Primary-side current control also enables low cost implementation of different constant current thresholds for each output voltage.

The device ensures safe operation with programmable, patented active fast output voltage discharge from 9V or 12V down to 5V. So, when the USB cable is unplugged from a Quick Charge 2.0 phone and then used with a non-Quick Charge 2.0 phone, the iW620 rapidly discharges the output voltage down to 5V, to protect the phone from damage.

The iW620 supports Quick Charge 2.0 High Voltage Dedicated Charging Port (HVDCP) Class A (5V, 9V, 12V output) applications and, with the iW1760 primary-side digital PWM controller, it provides fast voltage transition and low no-load power consumption of under 100mW. The iW620+iW1760 rapid charge solution provides comprehensive protection features: adjacent pin-to-pin short circuit and floating pin protection; built-in fault protections against output short-circuit, output over-voltage, output over-current, and current-sense resistor short; output current limit and over-load protection; and a dedicated pin for external over-temperature and over-voltage protection.

“Reducing  battery charge time is one of the most compelling trends today in smartphones,” commented Mark Tyndall, Senior VP Corporate Development & Strategy, GM Power Conversion Business Group at Dialog Semiconductor. “With our leadership position in accurate primary-side control in AC/DC power supplies from our iWatt acquisition, Dialog is excited to debut the first primary-side regulation solution for Quick Charge 2.0, delivering on our goal to be an early provider of  high power density rapid charge solutions.”