UCC28950 : How to design multiphase phase shift full bridge converter

Alpha,

Which external component values does the customer want more information on? What are they doing differently than the reference design?

The datasheet has many equations in it that provide information on how to calculate these external components. I would recommend that the customer use that as the guideline for the specific components they would like to adjust.

Hi Alex

Thank you for your reply.
Our customer would like to know the way of design "multiphase PSFB".

In your describe,they can use equations on the datasheet while I think the datasheet is not mentioned about multiphase design.

For example are there any differences the way of design Slope Compensation?
And also is there difference state space 1phase and 2phase?
If yes,could you provide how to design slope compensation of 2phase and any refference guides?

Please let me know if you can provide any reference literature since our customer want to know fundamental about multiphase design.
 
Best regards.

Alpha,

We have these two documents that your customer can use as a resource: http://www.ti.com/lit/an/slua609/slua609.pdf&rct=j&frm=1&q=&esrc=s&sa=U&ei=fngcVJLPI5HsoASnloLADw&ved=0CBQQFjAA&usg=AFQjCNEutP7dYaZw4PnF5mWiQSMlNOS9oA 

 http://www.ti.com/lit/an/slua560c/slua560c.pdf&rct=j&frm=1&q=&esrc=s&sa=U&ei=fngcVJLPI5HsoASnloLADw&ved=0CBoQFjAB&usg=AFQjCNGTZXWw4ubL9Qz_iSDIowhRcDgr5g

Hi Alex

Thank you for your prompt reply.

Although I think those documents were not described how to design slope compensation at more than 2phase shift full bridge,Is it wrong?

Please let me know about questions as below.

1. Are there any differences about how to design slope compensation single phase and multiphase ?

2. If yes,what should our customer refer to design ?

Please support this issue since our customer want to know about the above.

Best regards.

The amount of slope compensation is normally set at about 10% of the maximum current sense signal over one switching period. This is described in SLUA560B application report.  Why do you think it would be different for multiple PSFB's ?

Hi John

Thank you for your reply.

Although I have recognised there is no difference about the way of design of single phase and multiple phase,is that right?

This question is background as below.

Our customer have found the phenomenon that was increased ripple current in slave side and duty have been oscillation mode.
In addition they have designed slope compensation based on single phase and confirmed stable operation at single phase.
The way of control is PCM and current signal is feedbacked from primary side using CT.

Could you please tell why the phenomenon is occured as above?

Best regards.