Onsemi‘s mixed-signal controller designed for bridgeless totem-pole power factor correction (TP PFC) topologies. The target application for the NCP1681 is ultra-high density offline power supplies. The new controller builds on the success of the NCP1680 for designs up to 350 W, extending power capability into the kilowatt range.

In the past, TP PFC designs required the use of an MCU, which added complexity to the design and required coding. Now with the NCP1681, a full-featured TP PFC scheme can be implemented without coding by adding a few external components, saving time, cost, and footprint.

Commenting on the new product launch, Robert Tong, senior vice president and general manager of Onsemi‘s computing and cloud division, said: "The new NCP1681 extends the benefits of no-code TP PFC designs to higher power. This enables our customers to continue to improve their design energy efficiency, while reducing design time and cost, so that solutions can be brought to market quickly.”

The NCP1681 can be configured to operate in fixed frequency continuous conduction mode (CCM) or multi-mode operation, with the controller naturally transitioning between CCM and critical conduction mode (CrM) for optimum performance at various power levels.

The new NCP1681 high-power TP PFC controller combines mature control algorithms and novel features to provide a high-performance and cost-effective TP PFC solution that can also meet challenging energy efficiency standards such as "80Plus" or "CoC TIer 2" ” and other requirements to provide high energy efficiency standards over a wide load range.

The new NCP1681 is suitable for higher power supplies in the 350 W to several kilowatt range, operating from universal power input (90 - 265 Vac), and is suitable for a wide range of applications including server, high performance computing, telecom, industrial and OLED TVs. Under high voltage input, the energy efficiency of NCP1681 TP PFC scheme will reach nearly 99%.

In addition to TP PFC controllers, Onsemi offers a wide range of SiC MOSFETs and isolated gate drivers that can be used for fast legs of totem poles. SiC MOSFET devices feature low on-resistance (RDS(on)) and compact die size, ensuring low capacitance and gate charge (Qg), providing extremely high energy efficiency in shrinking system size, enabling high power density. When the NCP1681 is used with the NCP51561 galvanically isolated gate driver, a robust design can be achieved without sacrificing switching performance.