TPS548A28: overcurrent protection delay/response time

Jim Tsai

Part Number: TPS548A28
Other Parts Discussed in Thread: TPS54J060, , TPS548B28

Hi,

According to below DS description, LS FET stay ON when the current is above current limit threshold, what's the delay/response time after trigger current limit to LS FET ON?

I also found 68us, looks it's for undervoltage protection.

11 months ago

0 Jim Tsai 11 months ago

TI__Expert 4470 points

Hi,

Add one part TPS54J060, I saw the same description in DS.

I also need the delay/response time for TPS54J060.

0 Ryan Chen 11 months ago

TI__Expert 7986 points

Hi Jim,
I'm not sure I am understanding your question. The overcurrent limit is checked by the inductor current every using cycle by cycle valley current detect.
Once the current is too high, the low-side FET will stay on until the device current drops below the threshold which usually decreases the output voltage until under voltage protection is triggered. It will then wait for the 68 us, and 14 us for hiccup before trying to start up again.

Best,

Ryan

0 Jim Tsai 11 months ago in reply to Ryan Chen

TI__Expert 4470 points

Hi Ryan,

Sorry for confusing.

I mean do we have any spec define for the timing "t"?

trigger overcurrent limit => "t" => low-side FET will stay on

I need the "t" for TPS548A28 and TPS54J060.

0 Jim Tsai 11 months ago in reply to Jim Tsai

TI__Expert 4470 points

Hi Ryan,

I also need TPS548B28, thanks.

0 Ryan Chen 11 months ago in reply to Jim Tsai

TI__Expert 7986 points

Hi Jim,

Please see figure 7.3 on page 20 of the TPS548A28 datasheet. I do not have any other information table besides that stated in the electrical characteristics and the text from the datasheet. May I ask what is the issue that needs to be resolved?
Best,

Ryan

Power management

Power management forum

TPS548A28: overcurrent protection delay/response time