onsemi, a leader in intelligent power and sensing technologies, introduced its latest mixed-signal controller dedicated to bridgeless totem-pole PFC (TP PFC) topology. The NCP1681 targets ultra-high-density offline power supplies. Building upon the success of the NCP1680, which is suited for designs up to 350 W, the new controller extends the power capability into the kilowatt range.
In the past, TP PFC designs required the use of an MCU that added design complexity and the need for coding. However, with the NCP1681, only a few external components and no coding is needed to be added for a fully-featured TP PFC solution, thereby saving time, cost and space.
Commenting on the new release, Robert Tong, Senior Vice President & General Manager of Computing and Cloud Division at onsemi said “The new NCP1681 extends the benefits of code-free TP PFC design into a higher power. This allows our customers to continue to enhance the efficiency of their design while reducing design time and cost, thereby delivering solutions to market quickly.”
The NCP1681 can be configured to work in either fixed frequency continuous conduction mode or multi-mode operation, where the controller naturally transitions between CCM and critical conduction mode for optimal performance across power levels.
The new NCP1681 high-power TP PFC controller integrates established control algorithms with novel features to deliver a high-performance and cost-effective TP PFC solution. Challenging efficiency standards such as ‘80Plus’ or ‘CoC Tier 2’, that require high efficiency over a wide load range, can also be met.
The new NCP1681 is suited to higher-power power supplies from 350 W to several kilowatts range that operates on universal mains input (90 – 265 Vac), addressing a wide range of applications including server, high-performance computing, telecom, industrial and OLED TV. At the high line, NCP1681 TP PFC solutions will achieve close to 99% efficiency.
Alongside the TP PFC controllers, onsemi offers a wide range of SiC MOSFETs and isolated gate drivers that can be used for the fast leg of the totem pole. SiC MOSFET devices have low on-resistance (RDS(on)) and compact chip size which ensures low capacitance and gate charge (Qg), delivering the highest efficiency in reduced system size, thereby enabling power density. When NCP1681 is used with the NCP51561 galvanically isolated gate driver, a robust design can be realized without sacrificing switching performance.
