UCC28051: UCC28051 questions

Hideyuki Takisawa

Intellectual 1080 points

Part Number: UCC28051

Hi,

My customer has several questions.

Could you please check below?

Customer is referring to Japanese datasheet. Rev is C.

Q1. In datasheet Rev C, equation (30) describes ( VIN(min) × √2 × VDROP ). But is this ( VIN(min)－√2 × VDROP )? In Rev G, there are no description for equation (30).

Q2. What is the Fs(max) for UCC28051?

Best Regards,

Hide

over 7 years ago

0 John Griffin1 over 7 years ago

TI__Mastermind 34465 points

Hello Hide,
Rev C is a very old version of the datasheet. Rev G is the latest revision.
Please refer to Rev G for any issues.
Also the UCC28051 is a transition mode pfc controller so there is no maximum specified switching frequency.
This part is designed for a minimum frequency at max power and low line input.
The switching frequency varies with the instantaneous value of input voltage
Max frequency occurs around the zero crossings.
In practices it is of the order of a few hundred kHz

Regards
John

0 Hideyuki Takisawa over 7 years ago in reply to John Griffin1

TI__Intellectual 1080 points

Hi John,

Thank you for your answer.

Best Regards,

Hide

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UCC28051: UCC28051 questions