TPS259827LEVM: Regarding Driving High Current PWM Load

Hi Kevin,

Kevin Richardson said:

I am looking into implementing the TPS259827LNRGER device into our current system as we are facing difficulties with our current eFUSE internal reverse protection.

TPS25982 doesn't have reverse current blocking. If you need RCB when the rail is off, then I can propose TPS25983 which is p2p with this device but have capability to drive external FET for RCB. Also, that device is rated for higher Vin so will provide more buffer.

Kevin Richardson said:

Currently, we are driving two TEC chillers via PWM via a 24V rail that will be sourced through the eFuse. This is to make sure we are not driving more current than necessary and to protect the output from shorts.

Can you provide schematic of eFuse in your design and load details (I understand it is 24V/12A but how much load will be present during turn on and how much capacitor as it will also cause inrush current). Are you using PWM signal as EN of the eFuse.

Kevin Richardson said:

Each TEC takes around 6A peak current draw when enabled. When driving these two TECs via a low-side switch and a PWM generated via an MCU, will there be any issues we will face with this device? I ask since some eFUSES seem to not work well when sourcing a load controlled via PWM.

eFuse are designed for resistive or capacitive loads and from my understanding TEC is similar to resistive loads (please correct me here if my understanding is incorrect) so I don't issue in driving the TEC. Now when using PWM, there will repeated startups and device sees higher power dissipation during the startup so selecting the startup time will be important to prevent junction temperature to rise very high.

Best regards,
Arush

Hey Arush,

Yes, we are currently moving away from the internal reverse protection IC since it is causing misfaults that cause the eFUSE to turn off. We do not want this feature.

Currently, we only have ~10uF on each output rail to the TECs (2 in total).

We are also looking into using this eFUSE to provide the motor voltage rail to power two TMC5130 stepper motor driver ICs. Since stepper motors are inductive, is the TPS25982 not suitable? Or will we just have to bring up the current rating.

Thanks!

Hi sender,

Apologies for the delay. I am stuck in few other testing hence the delay. I will get back to you before tomorrow eod.

Best regards,
Arush

Hi Kevin,

The eFuse can support motor loads. We will have to see the motor load profile and set the current rating accordingly. Also, the eFuse have ITIMER pin which sets the blanking timer (OCP response delay timer) so we will have to set that also properly.

Best Regards,
Arush