UCC28070A: what modification should be taken when transferring from ucc28070 to UCC28070A?

Marsh Cai

Part Number: UCC28070A
Other Parts Discussed in Thread: UCC28070,

Hi teams,

Due to the supply issue, we introduced ucc28070a to CTM to replace ucc28070.

The main difference we noticed is the frequency range.

Therefore, What modification should we take to realize the extended Range Programmable Frequency(10 kHz to 300 kHz) from the old design based on ucc28070(30khz~300khz).

BRs，

Marsh

over 2 years ago

0 Harish Ramakrishnan5 over 2 years ago

TI__Mastermind 24365 points

Hi Marsh,

Thank you for the query on UCC28070.

UCC28070A can replace UCC28070. UCC28070A can support switching frequency from 10kHz to 300kHz, UCC28070 can support switching frequency from 30kHz to 300kHz as you noted, this is the difference between UCC28070 and UCC28070A. so UCC28070A can be used in the application where UCC28070 is used and the same excel/ Mathcad calculator can be used.

Regards,

Harish

0 Marsh Cai over 2 years ago in reply to Harish Ramakrishnan5

TI__Intellectual 2835 points

Hi Harish,

Thanks for your reply.

Let's make the question simple. Customer has a fixed design with UCC28070 on the board. Can we just replace it with the UCC28070A? If not, what modification should we take to make the circuit work properly. Thanks.

BRs,

Marsh.

0 Harish Ramakrishnan5 over 2 years ago in reply to Marsh Cai

TI__Mastermind 24365 points

Hi Marsh

Yes, it can be replaced.

Thank you

Regards,

Harish

0 Marsh Cai over 2 years ago in reply to Harish Ramakrishnan5

TI__Intellectual 2835 points

Hi Harish,

Thank you so much for the quick reply.

one more quick question: if we replace the UCC28070 with UCC28070A directly, what frequency range will the circuit operate at? 10khz ~ 300khz or 30khz ~ 300khz? And why?

BRs,

Marsh

0 Harish Ramakrishnan5 over 2 years ago in reply to Marsh Cai

TI__Mastermind 24365 points

Hi Marsh,

Frequency is programmed through RT pin resistor and these fixed frequency operation controllers.

Regards,

Harish

+1 Ulrich Goerke over 2 years ago in reply to Harish Ramakrishnan5

TI__Mastermind 33310 points

Hello Marsh,

Here is another way to put it:

The UCC28070A can directly drop into any design already using UCC28070 without making any other modifications.
The UCC28070A PFC will operate at the same frequency that the UCC28070 was operating at before replacement.

As Harish says, the UCC28070 and UCC28070A are fixed-frequency controllers, and the user programs the desired switching frequency within the controllers frequency range capability. The UCC28070A simply has a wider available frequency range to choose from than that of the UCC28070.

Since the existing PFC circuit already has a specific switching frequency programmed, a UCC28070A controller will switch at that same frequency.

Regards,
Ulrich

0 Marsh Cai over 2 years ago in reply to Ulrich Goerke

TI__Intellectual 2835 points

Hi Ulrich, Harish,

Well noted, very clear and thanks.

Marsh

Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

Power management

Power management forum

UCC28070A: what modification should be taken when transferring from ucc28070 to UCC28070A?