UCC28780: UCC28780 in DCDC (48-to-12V) applicaiton

Ella KIM

Expert 3862 points

Part Number: UCC28780
Other Parts Discussed in Thread: UCC2897A, LM5025, LM5026

Hello There,

Please let me understand UCC28780 application.

(1) Can this device be designed for DC/DC? If it's recommended for offline ACDC, what's the reason?

(2) Is there any suggestion for flyback converter for DCDC that support GaN FET?

My customer's design target is below :

- VIN = 48V

- VOUT = 12V/150Wmax

- Previously customer used to design a active clamp forward converter with UCC2897A. And they're looking for more optimized solution now.

over 2 years ago

+1 Jaden Ning over 2 years ago

TI__Expert 7080 points

Hello Ella,

UCC28780 is target designed for AC/DC application , it also can be used on DC/DC ,, that is depends on the input voltage and output power level. since UCC28780 operates at CRM, so the peak current will be high if output power level is high and input voltage is low. in such application , High RMS current will lead to high conduction loss , then efficiency will low. usually flyback topology are not recommended for high output power (>150W (CCM)). special for DCM or CRM operation.

In your application. the input voltage is 48V and output is 12V/150W. personally think active clamp forward topology still the optimization choice .

Thanks.

0 Ella KIM over 2 years ago in reply to Jaden Ning

TI__Expert 3862 points

Thank Jaden for comment.

If ACF (forward) is the optimization choice, it looks UCC2897A is the only solution that we can suggest. Could you let me know if we have any other IC for forward topology?

+1 Jaden Ning over 2 years ago in reply to Ella KIM

TI__Expert 7080 points

Hi Ella,

LM5025 could be another choice for ACForward.

Thanks

+1 Ella KIM over 2 years ago in reply to Jaden Ning

TI__Expert 3862 points

Thanks Jaden.

It looks LM5025 is under VM control and LM5026 is under CM control. Customer might be more familiar with CM control like UCC2897A, but they are not restricted to CM. Could you kindly let me know the difference of LM5025 and LM5026 in performance perspective?

0 Jaden Ning over 2 years ago in reply to Ella KIM

TI__Expert 7080 points

Hi Ella,

Active clamp forward already out of my support. Could you please create a new post for your question about LM5025 and LM5026?

Thanks.

0 Ella KIM over 2 years ago in reply to Jaden Ning

TI__Expert 3862 points

I see. Thank you Jaden!

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UCC28780: UCC28780 in DCDC (48-to-12V) applicaiton