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TPS25947: Can TPS259474L detects over-current and set at 100 mA?

Tony Zhang
Prodigy 205 points
Part Number: TPS25947
Other Parts Discussed in Thread: TPS2640, TPS24710, TPS2490

Dear Friend

I need a load switch to provide an over-current protection between 100 mA to 500 mA and set based on applications, which means the load switch must be able to sense and action at a minimum 100 mA.  The question is because the datasheet of TPS259474L only provides over-current settings data from 500mA, I am not sure whether this device is capable of detecting and setting an over-current as low as 100mA.

In case this device is not capable of low current protection, please suggest any other load switch device with 3-20Vin, 1 to 4A specs (plus overcurrent circuit breaker function). 

another question for TPS259474L is: when an over-current is detected, besides internal FET shutdown, how does the PG pin/signal go? 

 Thanks

Tony

  • 0
    TI__Guru* 79181 points

    Hi Tony,

    Thanks for reaching out. 

    TPS259474 might not be suitable here. PG will go low on CB action:

    1. Do you only need circuit breaker? Current limit device can work?

    2. Please check TPS2640 device. It can support overcurrent detection upto 0.1A and also through mode pin we can choose CB function.

    Regards

    Kunal Goel

  • 0
    Prodigy 205 points

    Hi Kunal

    Thank you for your reply.

    TPS2640 looks good, but starting work from 4.2V.  I have two circuits to be protected, one circuit working up to 20V (from a booster) over-current at 100mA, and another circuit working at 3V (from a LDO) over-current around 300mA. I expect one chip for both circuits.

    What do you think about TPS24710? its maximum Vin=30V, should be able to work at 20V.

    I can choose Rsens = 0.25 ohm, thus, current limit threshold = 100mA, fast trip threshold = 240mA, and under latch mode, I will get circuit breaker function. Am I right?

    Or any other good suggestions?

    Yes, I need a circuit breaker function, at least a PG or FLT signal (active low) allowing me to hook up with EN pin of booster/LDO before the eFuse device, which also completes a circuit breaker function when an over-current occurs. So, internal FET is not really necessary.

     Best Regards

    Tony

  • 0 in reply to Tony Zhang
    TI__Guru* 79181 points

    Hi Tony,

    We will check and get back on suitable hot-swap.

    Regards

    Kunal Goel

  • 0 in reply to Kunal Goel
    TI__Mastermind 39240 points

    Hi Tony,

    Maximum recommended voltage of TPS24710 is 18 V. You should use TPS2490. 

  • 0 in reply to Avishek Pal
    Prodigy 205 points

    Hi Avishek

    I have mentioned that I have one circuit working at 3V and I need an eFuse over-current controller working from 3-20V. 

    Unfortunately, TPS2490 starts working from 9V.

    Regards

    Tony

  • 0 in reply to Tony Zhang
    TI__Mastermind 39240 points

    Hi Tony,

    We don't have any device which can work from 3 V to 20 V input voltage. 

  • 0
    Prodigy 40 points

    Regarding the 100mA detection, the datasheet shows that increasing the ILIM resistor will decrease the current threshold and increases accuracy. 

    Overcurrent Threshold, RILM = 6.65 kΩ    0.425 0.500 0.575  (+-0.075A)

    Overcurrent Threshold, RILM = 3.32 kΩ    0.850 1.007 1.150 (+-0.150A)

    Using the ILIM formula, what is the expected threshold using a 33.3kOhm resistor and what is the expected accuracy? 

  • 0 in reply to Cian Martin
    TI__Mastermind 39240 points

    Sorry, we don't have those data.  Current limit is characterized with two (2) RILIM values only.