AN-9066

APPLICATION NOTE

Output Power [W]

0

100

200

300

400

500

600

93

94

95

96

97

98

UniFET, 20A/500V

Super-junction, 21A/500V

Figure 7. Efficiency Curves with 115V AC Input

The efficiency results are shown in Figure 7. There is not

much difference in efficiency when in heavy load.

the UniFET at same drain current rating and therefore will

have more conduction loss advantage as the load becomes

heavier. The smaller switching loss of the UniFET

the UniFET shows slightly better performance. In the light-

load area, the switching loss dominates the power losses

and the UniFET surpasses the super-junction device.

Conclusion

The performance of the UniFET

device level and system level. It showed good results

against the super-junction device and can be an optimum

solution in DCM PFC application as long as required

breakdown voltage of the boost switch is 500V. The

interleaved DCM PFC is gaining attention recently and this

is another application where the UniFET can be considered

as a high-performance, cost-effective boost switch.

© 2009 Fairchild Semiconductor Corporation

www.fairchildsemi.com

Rev. 1.0.1 • 4/3/09

6