6 January 2023
Transphorm releases compact 240W power adapter reference design with TO-220 GaN FETs
Transphorm Inc of Goleta, near Santa Barbara, CA, USA — which designs and manufactures JEDEC- and AEC-Q101-qualified gallium nitride (GaN) field-effect transistors (FETs) for high-voltage power conversion —has announced the availability of its new 240W power adapter reference design. The TDAIO-TPH-ON-240W-RD deploys a continuous-conduction mode (CCM) boost PFC + half-bridge LLC topology to deliver a peak power efficiency of over 96% with a power density up to 30W/in3.
Transphorm’s design uses three SuperGaN FETs (TP65H150G4PS) each with an on-resistance of 150mΩ. The GaN FET comes as a 3-lead TO-220, a well-known and long-trusted transistor package that offers superior thermals at lowline for higher-current power systems running power factor correction (PFC) configurations.
The reference design is intended to simplify and quicken power system development for applications such as high-power-density AC-to-DC power supplies, fast chargers, IoT devices, laptops, medical power supplies, and power tools.
Key specifications and features
As a 240W 24V 10A AC-to-DC power adapter reference design, the TDAIO-TPH-ON-240W-RD pairs the TP65H150G4PS GaN FETs with onsemi’s off-the-shelf NCP1654 CCM PFC controller and NCP1399 LLC controller. The design uses a 25mm heatsink that produces a power density of over 24W/in3. The power density can increase by about 25% to 30W/in3, depending on the heatsink design.
This high power density and efficiency range is primarily due to the FET’s packaging, as Transphorm offers what is claimed to be the only high-voltage GaN devices in a TO-220 currently available. Power adapters, along with all universal AC-to-DC power supplies, require high current at lowline (i.e. 90Vac) which can require paralleling two PQFN packages (as typically seen with e-mode GaN) to achieve the desired power output. This method reduces a power supply’s power density while requiring 2x part count. Transphorm’s TO-220 packages mitigate this, providing what is claimed to be unparalleled power density at a lower cost — a result not currently possible with e-mode GaN, the firm adds.
Other specifications and features include:
- operation over a universal input voltage of 90Vac to 264Vac;
- over 96% peak efficiency and flat efficiency curve across line and load;
- tight switching frequency regulation for improved input EMI filter utilization;
- over 180kHz switching frequency operation for compact implementation.
The new reference design joins a broad portfolio of adapter/fast charger design tools that currently includes five open frame USB-C PD reference designs ranging from 45W to 100W, as well as two open frame USB-C PD/PPS reference designs for 65W and 140W adapters.