• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 175 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.

TPS22919: Restart conditions

Yusuke Mukuno
Expert 7395 points
Part Number: TPS22919

Hi Expert,

My customer is testing TPS22919 behavior at over load situation with e-load.

When the output current is increased with e-load. TPS22919 was shutdown at Iout = 2.9A. 

At this time, Vin- Vout < 1.5V, Vout > Vsc.  However the device seems to be shutdown state 

Is it thermal shutdown? (The package temp is 93C)

Then they decreased output current slowly.

 The device restarted at  Iout <100mA.  (They tried to check a few times, always around 100mA. Not shutdown when they keep 200mA setting)

They think, it is not thermal hysterisis. Does the device have any restart condition other than thermal hysterisis?

Thanks

Mukuno

  • 0
    TI__Mastermind 34935 points

    Mukuno-san,

    Is the customer using the eLoad in constant current mode? If so- could you try changing it to constant resistance mode (CR)?

    Resistive loads in nature will always have current proportional to the voltage applied across it by the factor of its resistance. During the FET turn-on period, the voltage across the FET Vds ramps down (on the other hand, the voltage across the resistor will be ramping up), and the current through the FET ramps up. The IV overlap loss across the FET will be the integral of the voltage Vds and current Id.

    In the case of e-load in constant current mode, the e-load will have a closed loop system where it always wants to draw the preset current. This will lower the resistance during FET turn-on process, which makes Id much larger from time periods t2 to t3. This can cause extra power loss as the area under the integration curve would be larger and cause thermal shutdown during the initial power on phase.

    In short- try to test with either a set power resistor or change the e-load to constant resistance mode.

    Best Regards,
    Timothy Logan