• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 248 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS2492 Current Sensing

Enrico
Prodigy 170 points
Other Parts Discussed in Thread: TPS2492

I'm a disty FAE, I've a problem with a customer trying to use TPS2492. He is planning to use the Overcurrent feature of this device. He wants the overcurrent circuitry to act for a current not really high (200mA) and calculated a Rsense of 0.25 ohm for his application. The device seems to don't work properly beacuse as the customer give a Vin of around 26V (rising from 20V) with a current absorption of  less of 100mA the overcurrent just go active. The suspect is that something is not properly working inside the device because of a Rsense that is much higher than those of the examples reported by the datasheet.

Does all of this ring some bells to some of you?

  • 0
    TI__Expert 7990 points

    The current sense circuit is only driven by the diffferential voltage.  Given your votlage and currents, it is not expected the absolute R is a limiting factor in circuit currents.

    Measure the actual switch (sense resistor) current with a (calibrated / offset corrected)  current probe.  Generally, putting the probe on the MOSFET source might be a good place.  Do not include any output capacior currents or other loading except maybe the OUT pin. 

    Consider the effects of the power limit reducing the instantaneous (operating) current limit below the maximum (50mV sense voltage). 

    There is a TINA spice model and a calculator tool available from the device home page.