TPS2557: About mechanism of the current limit

Hide

Part Number: TPS2557

Hi Team,

We would like to know about mechanism of the current limit.

We understand that If the load current reaches current limit value, this device coordinates the resistance of FET by the Driver.

Is my understanding correct?

Regards,

Kanemaru

over 6 years ago

0 Bob Ma over 6 years ago

TI__Expert 8980 points

Hi, Kanemaru,

You are correct. The device will coordinate Rds to limit current. In other words, FET will be in saturation region when current is limited, limited current is set by Gate.
Feel free to ask if any more questions.

Regards,
Bob

0 Hide over 6 years ago in reply to Bob Ma

Guru 21045 points

Hi Bob-san,

Thank you for your response.

I understand that Rds is the more than 35mohm(max) in the current limit.

[For example]

Rds is around 2.5ohm and VOUT=2.5V if VIN=5V, IOUT=2A, current limit =1A.

So, PD is 2.5W (2.5ohm * 1A).

Is my understanding correct?

Regards,

Kanemaru

0 Bob Ma over 6 years ago in reply to Hide

TI__Expert 8980 points

Hi, Kanemaru-san,

You are correct. PD can also be calculated by (Vin-Vout)* Ids=2.5W.

Regards,
Bob

0 Hide over 6 years ago in reply to Bob Ma

Guru 21045 points

Bob-san,

Thank you for your prompt reply.

I understand. Thank you very much.

Regards,

Kanemaru

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TPS2557: About mechanism of the current limit