TPS2121: Application issues.

Reed

Part Number: TPS2121

Tool/software:

Hi,

Using TPS2121 chip for dual power switching, the following issues were found, please help analyze.
1. At the 12V end, using a switch (soft switch or hard switch) for control will result in a 5V power outage reset restart when the 12V is turned off.
2. If the 12V plug is directly plugged in and out, it will not reset when unplugged, but there is a probability of power failure reset when plugged in.

1 month ago

0 Elizabeth Higgins 1 month ago

TI__Genius 15540 points

Hi Reed,

It is unclear to me what are the DC values of your two input voltages. However, I have assumed 7.65V and 5V and filled out your external circuitry in the following calculator.

As you can see the switchover points are going to be very similar so it is important to add some hysterisis to avoid multiple switchover points causing a voltage dip.

Please check out the following FAQ for further details: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1023453/faq-tps2121-how-do-i-achieve-a-seamless-power-switchover-using-ti-s-power-mux-devices

6648.TPS2121 PR1 CP2 Calc E2E_Reed.xlsx

Best Regards,

Elizabeth

Power management

Power management forum

TPS2121: Application issues.