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# UCC28070: UCC28070

Part Number: UCC28070

Hi TI experts:

I use the UCC28070 in my 2KW AC/DC supply solution,

the boost Lm is about 22uH which calculated by the UCC28070 design tool。

but the in Webench the Lm is 22uH，

but I found the Lm is 200UH in PMP4259 which is the 3KW AC/DC supply.

So I would like to ask, is it ok to use 22uH for 2KW? or i need use the Lm more than the 200uH, thx

• Hi Jack, an expert will get back to you soon. ——Teng

• Hi, Jack

Beside output power, you need to know switching frequency and ac input range and current ripple coefficient, then you can calculate PFC inductance.

Suppose: ac input range: 85V~264Vac

switching frequency:70kHz

current ripple coefficient: 0.4

output power:2kW

based on above conditions, 200uH is the corrent PFC inductance.

Regards,

Yunsheng

• Have any calculate tool for UCC28070 used as bridgeless controller?

• Hi, tu hs

There is no too much difference to calculate related parameters with UCC28070, either interleaved CCM PFC or Bridgeless PFC. The  difference is full power for power devices: PFC inductance and PFC MOSFET and diode. Power devices of bridgeless PFC should handle two times power as interleaved CCM PFC.

For example: full power of PFC is 2000W. The power devices of bridgeless PFC is calculated with 2000W, but the power devices of interleaved CCM PFC is 1000W.

You can find calculate tool for UCC28070 used as interleaved CCM PFC controller. You can use this calculate tool for Bridgeless PFC calculation.

http://www.ti.com/product/UCC28070

Regards,

Yunsheng