Low efficiency, large size and high cost are three major problems with existing PD adapter solutions. It uses GaN (Gallium Nitride) switches (more expensive) and two-stage power conversion (large size and more loss). The solution is not optimized for current PD3.0 (Power Delivery) and PD3.1 standards, where the output voltages should be changed from 5V to 48V with a maximum current of 5A for a maximum output power of 240W.
The existing PD adapter uses a two-stage AC to DC conversion. The first stage is the Boost converter operating at critical conduction mode to achieve Power Factor Correction. The second stage uses LLC resonant converter to produce a fixed intermediate voltage. The actual output voltage is regulated in a third stage, another Buck converter, to produce 5V to 48V. Since the power loss of the Boost converter is high, the latest switching device, GaN (Gallium Nitride) switch should be used to reduce the power loss. In addition, the Boost inductor is large in size and high in power loss. The cost is high because of GaN switch and total of three-stage power conversion.
DigiQ proposes a new power architecture together with digital control technology to reduce the power loss, size, and cost of the AC to DC converter. With DigiQ technology, conventional MOSFET can be used as the main switch. Therefore, smaller size, lower cost, and higher efficiency PD3.0 and PD3.1 USB Type-C fast chargers can be produced.