Any correction plan that can meet the requirement of high PF value even under light load

Faith Luo

Intellectual 500 points

Other Parts Discussed in Thread: UCD3138

Dear Sir：

Under full load, the power factor is the highest at AC90V and slightly lower at 264V.

Under specific input voltage, full load power factor is the highest, light load will reduce it.

Could you tell why and explain the details?

Would you tell me if there is any correction plan that can meet the requirement of high PF value even under light load?

Thank you very much.

over 6 years ago

0 Ian Bower over 6 years ago

TI__Genius 17090 points

An expert will be replying soon.

0 Bosheng Sun over 6 years ago in reply to Ian Bower

TI__Expert 7260 points

which TI device is used in your PFC?

0 Faith Luo over 6 years ago in reply to Bosheng Sun

Intellectual 500 points

Hi Bosheng:

I have no part number, just the customer is looking for this convenient solution.

Firstly I would like to ask you why pf is lower under light load, and then whether TI has any advantaged solution.

Thank you very much.

0 Faith Luo over 6 years ago in reply to Faith Luo

Intellectual 500 points

Hi Bosheng:

Product requirements: full voltage input, power less than 300W, pf greater than 0.9 under 20% loading

Thank you very much.

0 Bosheng Sun over 6 years ago in reply to Faith Luo

TI__Expert 7260 points

The X-cap in EMI filter generates reactive current which is leading input voltage, this makes the power factor less than 1. This situation gets worse at light load, since the reactive current takes more weight in total input current. If you choose TI digital controller UCD3138, you can delay the current loop reference to improve power factor.

Power management

Power management forum

Any correction plan that can meet the requirement of high PF value even under light load