Dialog Semiconductor’s Qualcomm Quick Charge 3.0 (QC3.0) chipset has now started volume production: it offers constant-power profiles for ease of configuration. The chipset, which pairs the iW1782 primary-side AC/DC controller with the iW636 secondary-side controller, offers a constant power profile for 3-A USB-C charging, which optimises transformer design and minimises charge time. A complementary digital green-mode synchronous rectifier controller, the iW673, may be used with the QC3.0 chipset to enable an overall system efficiency of approximately 90%. This minimises heat dissipation so increased output power adapters in smaller compact form factors can be manufactured, adding consumer appeal to the design of AC/DC adapters.
Used in AC/DC mobile power adapters, Dialog’s iW1782 PrimAccurate primary-side digital pulse width modulation (PWM) controller is coupled to the secondary-side iW636 Rapid Charge interface chip via a digital communication link. It receives all commands from the iW636 through an optocoupler and the chipset has a fast, dynamic load response. Adapters can be configured for multi-level outputs from 3.6V to 12V in 200 mV increments, depending on the voltage requested by the mobile device, and the solution is backwards compatible with QC2.0 and USB BC1.2 charging requirements.
Double-layer cable protection is provided by the chipset, without the need for additional components. On the primary side, the iW1782 incorporates Dialog’s SmartDefender advanced hiccup technology which protects mobile devices from heat damage caused by short circuits in dirty or damaged charging ports, or worn USB cables and connectors. It does this by reducing the average power delivered to a short circuit by up to 75% without latching off. On the secondary side, Dialog’s D+/D- over-voltage protection addresses bus voltage soft shorts. These protection features result in safer, more reliable rapid charging and avoid excessive heat build-up. No-load power consumption is less than 10 mW at 5V/2A output.
The iW673 is a synchronous rectifier controller for flyback converters that emulates the diode rectifier on the secondary side