Dialog Semiconductor plc is debuting its high efficiency ac-dc adapter interface IC for Qualcomm® Quick Charge 2.0 power supplies. The new iW620 rapid charge interface IC resides on the secondary side of the ac-dc charger power supply and works with Dialog’s iW1760 PrimAccurate™ primary-side digital pulse width modulation (PWM) controller. Efficiency as high as 88% enables the higher power density needed for smaller form-factor fast charging adapters. Quick Charge 2.0 is a proprietary protocol from Qualcomm Technologies, Inc., a wholly owned subsidiary of Qualcomm Incorporated, for charging smartphones, tablets and other mobile devices up to 75% faster than conventional USB charging technology.
Dialog's Quick Charge 2.0 rapid charge ac-dc adapter solution delivers high efficiency up to 83% 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 rapid charge 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.
Current sensing is performed by the iW1760 on the primary side, eliminating the need for a secondary-side current sense resistor for 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 iW620 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.
"Reducing battery charge time is one of the most compelling trends today in smartphones," said 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."
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.