LM5122EVM-2PH: Current sharing is not balancing for a 2-phase design

Robin Yu

Intellectual 2190 points

Part Number: LM5122EVM-2PH
Other Parts Discussed in Thread: LM5122

Hi team,

Now customer is using our LM5122 to do a design.

But they find the current of 2 phase is not that balancing as out our EVM.

Could you please help provide some suggestions?

The schematic pdf is not allowed by customer. So only picture could be provided. Sorry about this.

Thanks.

Robin

over 6 years ago

0 Youhao Xi over 6 years ago

TI__Guru* 78430 points

Hi Robin,

This seems being caused by the mismatch of the internal 1.2V shift circuit from the COMP to the PWM comparator, resulting in the different peak current. Also the tolerances in the CS amplifier and SLOPE comp also added to the errors. If you want to have well balanced current sharing, you may consider the scheme in the following article, which is tested on the different device but the idea works.

Thanks,

Youhao Xi, Applications Engineering

0 Robin Yu over 6 years ago in reply to Youhao Xi

TI__Intellectual 2190 points

Hi Youhao，

Do you mean it is caused by mismatch of devices? If so, the mismatch may varied with different boards?

Thanks.

Robin

0 Youhao Xi over 6 years ago in reply to Robin Yu

TI__Guru* 78430 points

Hi Robin,

Yes if it is the tolerance, the unbalance will vary from boards to boards.

Thanks,

Youhao

Power management

Power management forum

LM5122EVM-2PH: Current sharing is not balancing for a 2-phase design