UCC28C55-Q1: regarding UCC28C55-Q1 Vref state during comp pin pull-down

Karthik karri

Part Number: UCC28C55-Q1

Tool/software:

Hi Ti Team,

I am using UCC28C55-Q1 in my DC-DC converter.

I am using VREF 5V to supply protection circuit of my internal circuit.

If i pull-down COMP pin with MOSFET during some fault condition.Still i need VREF-5V should be ACTIVE .Is is ACTIVE ??

or After i pull-down COMP pin , VREF-output will be zero?? can you please check and cofirm this...

0 Hong Huang 6 months ago

Hi,

VREF still at 5V when you pull down COMP to low. COMP max source current about 5mA while VREF can still stay at 5V with a current over 20mA.

0 Karthik karri 6 months ago in reply to Hong Huang

OK Thanks Hong,

what the 5V tolerance range or Accuracy when it is consuming 20mA??

0 Hong Huang 6 months ago in reply to Karthik karri

Hi,

The datasheet has specs:

0 Karthik karri 6 months ago in reply to Hong Huang

Hi Hing,

Based on required frequency i selected RT,CT from the plot given in datasheet(attached below)

i want to know tolerance in frequency variation with respect to RT,CT values . i considered 0.1% resister and capacitor values.

But there is no formula to do that .can you check and given recommdation how can i check the tolerance or any formula for it ???

Also i need

0 Hong Huang 6 months ago in reply to Karthik karri

Hi,

No formula is available fosc and its tolerance is specified in the datasheet. You need to consider +/-10% as maximum tolerance.

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