Can TPS51220 be used in 2-phase single output application?

Hi,

None of these devices can be used for single output converter

Regards

Mike

Mike,
Thank you for reply.
Yes I known the datasheet does not say it can be used in this way. While it seems there is not any obstacle on this way.
Observing the block diagram you can find the error amplifier in tow channels are current mode outputs. That means it is possible to share one error amplifier between two channels by simply connecting COMP1 and COMP2 together. I think it is feasible to connect two outputs together if this (sharing same VFB AMP between two channel) is possible.
Is it correct?
Regards,
John

Hi John,

I don't agree with you.

if you connect COMP1 and COMP2 together, how will you connect VFB1 and VFB2? also connect together to the single feedback?

you know the two error amp of two channels will not have same input offset, which means if one error amp think VFB is regulated, and another amp must think VFB is not regulated yet, this will cause problem.

you can try if you insist your method works

regards

Mike

Mike,
That is easy. As with TPS40140, we can use VFB1 as feedback, and connect VFB2 to an appropriate level (such as VREF2, GND, or floating, I am not sure) to make the current output from COMP2 at lowest level. This will make the COMP1/2 signal is dominated by VFB AMP1. The reason why do not use TPS40140 directly is it does not have Auto-skip mode.
Thank you,
John

John,
In this case COMP2 amp will be over driven(since VFB2 is high), and sink max current, and COMP1 amp will source current to raise up COMP1/2.
if the driving capability of COMP2 amp is larger than COMP1 amp, COMP1/2 will drop low?
I suggest you apply an EVM to double confirm

regards
Mike