TPS7A84: Detection of Overload and Short circuit

masahiko shimizu

Part Number: TPS7A84

Hi,

I want to know about detection of Overload and Short circuit.
TPS7A84 has two value of current limit.
it is Ilim and Isc.

How does TPS7A84 detect the different of Overload and Short circuit?

Best regards,
Shimizu

over 8 years ago

0 David Hopkins over 8 years ago

TI__Expert 8905 points

Hi Shimizu,

The TPS7A84 detects both events by mirroring the current through the pass device with a current mirror. The foldback (the difference between Isc and Icl) is that the short circuit current limit prevents thermal runaway when Vout is shorted to ground (in conjunction with thermal shutdown), while Icl keeps the current from spiking if the load draws too much current but doesn't look like a short circuit.

-David

0 masahiko shimizu over 8 years ago in reply to David Hopkins

Guru 11235 points

Hi David,

Thank you for your support.

Does TPS7A84 watch "the current slope of mirror current" or "Vout voltage level" for deciding Short circuit or Over load?

Best regards,
Shimizu

0 David Hopkins over 8 years ago in reply to masahiko shimizu

TI__Expert 8905 points

Hi Shimizu,

Most devices with foldback current limit rely on the output voltage level to detect when the output is shorted to ground, including the TPS7A84.

-David

Power management

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TPS7A84: Detection of Overload and Short circuit