The iW620 rapid charge interface IC resides on the secondary side of the AC/DC charger power supply and works with the company’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 Technlogies, Inc., 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 approaches. 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 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 9 V or 12 V down to 5 V. 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 5 V, 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