LM5046 in 3 phase AC-DC converter

Shrikant Lokhande

Other Parts Discussed in Thread: LM5046, LM5045, UCC28950

Hello all,

I have to design a SMPS with 3 phase AC input (3 wire) to 28.5V DC @ 80A.

I have chosen a full bridge push pull topology for this application, And I'm considering using LM5046 phase shifted full bridge PWM controller for the same.

But I have seen that most of the appliactions developed using this controller are of voltage aroung 100V input.

In my case my DC voltage could be some where around 750VDC(considering max vtg).

I have learnt that using an external regulator may allow me to use LM5046 at higher voltages than 100VDC specified.

I'm concerned about the other pins to the IC, whether I can use the same test circuit shown in datasheet with added external regulator.

I will appreciate your comments on this and if any application note available please let me know.

Also if you can explain how LM5046 gives phase shift, as the internal block diagram seems to be exactly same as that of LM5045.

Thanks and Regards,

Shrikant L.

over 11 years ago

0 John Griffin1 over 11 years ago

TI__Mastermind 34465 points

Hi Shrikant,

The LM5046 is suitable as a phase shift controller for input voltages of 30v to 75v. For higher voltages you should consider the UCC28950. The product page http://www.ti.com/product/ucc28950 contains all the information you will need to to understand the operation of this device.

Regards,

John

0 Shrikant Lokhande over 11 years ago in reply to John Griffin1

Intellectual 655 points

Hi John,

Thanks for the reply. I'll go through the datasheet and application notes for ucc28950 .

I couldnt find the significance of the phase shifted full bridge PWM controllers over normal full bridge PWM controllers, I'll appreciate if you can explain about it in brief.

Thanks and Regards,

Shrikant L

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LM5046 in 3 phase AC-DC converter