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TPS25924: Current limiting setting vary over temperature

Renan Santos Adriano
Mastermind 22380 points
Part Number: TPS25924
Other Parts Discussed in Thread: TPS25921A

Hi Team, 

My Customer created a set-up to test the current limit over temperature for TPS259241 and TPS25921A. Using TPS259241 and TPS25921A efuse's and the datasheet circuit configuration. The TPS259241 current limit, which is set to 2.5A, is varying a lot over temperature. While this behavior is not present with the TPS25921A

Can you explain why or make suggestions to improve this?

Regards,
Renan

  • 0
    TI__Guru 57737 points

    Hi Renan,

    The current limit variation specified in the datasheet is guaranteed across temperature,  process and voltage.

    Can you share the customer schematic and details about test  setup.

  • 0 in reply to Praveen GD
    TI__Mastermind 22380 points

    Hello Praveen,

    Thank you for your response.

    My customer provided this information:

    Temperature are measured with a thermocouple glued to the top of the package. The temperature of both rapidly rises to 100- 110C during current limiting

    Voltage is 5.8V and he is using an electronic load to vary the current and a lab power supply for the voltage source. The circuit was taken directly from our datasheet.

    Regards,

    Renan

  • 0 in reply to Renan Santos Adriano
    TI__Guru 57737 points

    Hi Renan,

    It is not recommended to use electronic load for testing efuse current limit functionality. Always use resistive loads to evaluate eFuse devices.

    • With resistive loads, the output operating point will be decided by the eFuse in current limit mode of operation. In case of active loads (e-load), the output voltage & current will be decided by both the e-load characteristics and eFuse characteristics in current limit mode. So, load current cannot be limited by the set current limit of the eFuse. You will observation different current than the current limit value.

    •  Alternate explanation: When the eFuse device reaches current limit, the device acts as a current source. If an electronic load is used for testing in CC mode, which turns out to be placing two current sources in series in the network. When the electronic CC load exceeds set current limit of eFuse device, the electronic load tries to pull down the output voltage and shifts the operating current other than the current limit value.