TPS55288-Q1: Clarification on the current limit setting

Martin Tan

Part Number: TPS55288-Q1

Hi,

I would like to clarify on the output current limit setting. I observe that if I set the output current limit to 5 A and drive the output with 5A load, it seems to lost regulation as seen on the waveform capture below where the output drop sharply. However the output is OK if I set the current limit to 5.1A while driving similar load. Is this something to do with the internal comparator that the current limit need to set higher than the max load requirement in the design? Please advise.

3 months ago

+1 Bryce Xun 3 months ago

TI__Genius 16920 points

Hi Martin,

Thanks for reaching out.

Please notice that the ISP-ISN (voltage on output current sense resistor) which compares with the internal limit threshold also has variation. And it is recommended to use Kelvin connection for the ISP, ISN signal sensing.

For output current limit protection, considering the variation, it is suggested to leave some margin for the ISP-ISN value.

BRs,

Bryce

0 Martin Tan 3 months ago in reply to Bryce Xun

Prodigy 20 points

Thank Bryce for your advice, I have adopted the Kevin connection in the layout as well. So I will add some margin based on the table your have provided.