In 2021, the USB-IF Institute introduced USB Type-C Cable and Interface Standard V2.1, which updated the section on power supply capabilities. USB PD3.1 specification puts the original USB PD3.0 content into the Standard Power Range (SPR), the maximum Power is kept at 100W, and Extended Power Range (EPR) is increased. The maximum power is expanded from 100W to 240W. To help customers shorten the development cycle, WAYON has introduced a 240W power reference design, which supports voltage input in the wide range of 100-240VAC ~50/60Hz, 20V output, maximum current 12A, full load efficiency ≥96.5%, output voltage ripple < 300mV. The overall size is only 105mm*58mm*22mm. This design is suitable for adaptors, POE power supply, high power density industrial power supplies, power tool chargers, and server power modules.
Figure 1: PCB of WAYON 240W bridgeless solution (Front)
Figure 2: PCB of WAYON 240W bridgeless solution (Back)
Figure 3: Topology Framework of WAYON 240W bridgeless solution
WAYON 240W power supply solution key parameters
This solution has the following features compared to the standard bridgeless FPC structure in Figure 4:
1. D1 and D2, as bypass bridge arms, need rectifier bridges under normal operating conditions. By using the LOW VF rectifier bridge for D1, D2, D3 and D4, the MOSFETs of the low frequency bridge arm can be spared.
2. During high frequency bridge arm switching, the synchronous side GaN is not driven to operate at full cycle when the sinusoidal AC voltage is low. This can lead to excess GaN heating outside and after the SiC SBD, the positive temperature SiC SBD does active thermal equalization of the GaN and acts as a full bypass device for the GaN.
3. Two low-resistance SJ MOSFETs and one driver can be omitted, while a more cost-effective 100mΩ, 650V GaN device with two external 3A SiCs can be used, equivalent to a conventional PFC. Compared with the classic bridgeless PFC structure, the overall cost is significantly reduced (about 10-15RMB).
Figure 4: Bridgeless PFC topology with conventional structure
Figure 5: WAYON bridgeless omits the low frequency bridge arm MOS
Energy Efficiency Test
WAYON 240W power supply solution has a significant efficiency improvement under half-load conditions compared to common silicon MOS products on the market. It reaches an efficiency of over 96.5% under full-load conditions, which is comparable to the efficiency of bridgeless PFC using SJ MOSFET with conventional structure. However, compared to the SJ MOSFET +70mΩ GaN device bridgeless topology, WAYON’s optimized bridgeless PFC has an outstanding cost advantage.
满载：full load
Temperature Rise Test
The image above shows the thermal image of the WAYON 240W power solution running continuously for 2 hours at 25°C ambient temperature at 115V/60Hz without a cooling pad. As can be seen, due to the high efficiency topology design and with WAYON's outstanding performance devices, the measured maximum temperature at the back of the 240W power solution is only 77.4°C.
Based on the rich power device product line, WAYON deeply combines the professional power semiconductor solution R&D team, which can quickly launch self-designed, cost-effective and excellent whole machine solutions.
