UCC28060

Patrick Chung

Other Parts Discussed in Thread: UCC28060

Hi,

I am currently using UCC28060 to build a PFC, the two MOSFETs are set to permanently interleaved (Phase management Disabled). It works fine except during power up, the two MOSFET gate drives are found to be in phase, instead of interleaved, this happen when the output of PFC is ramping up. Once the output is regulated, the gate drives resume to normal (interleaved). Is this normal?

Thanks,

over 13 years ago

0 Mike O' over 13 years ago

TI__Guru* 85896 points

The UCC28060 uses a phase lock loop to obtain the 180 degree phase shift. During power up or when the device hits peak current limit both phase start off in phase. Once peak current limit is no longer being triggered the phase will slowly become out of phase this generally takes roughly 5 switching cycles.

0 CWilson over 13 years ago

Expert 1920 points

Just for my curiosity.. Why keep it in interleaved mode all the time? The one Boost leg can be disabled by the UCC28060 when not needed..?

0 Mike O' over 13 years ago in reply to CWilson

TI__Guru* 85896 points

You are correct you do not have to have both phases on all of the time. If you don't connect the PHB pin to the comp you can use this control to turn-on and off the second phase.

0 CWilson over 13 years ago in reply to Mike O'

Expert 1920 points

My efficiency was exellent when the IC turned on and off the PHB instead of having the both on at the same time.

Power management

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UCC28060