TPS62868: Ramp speed issue

Hi,

Are you trying to change the soft start time?  Those bits change the ramp speed for DVS.  See section 8.4.4 in the D/S.

What is your Vin, Vout, Iout, and soft start time requirement?  This SS time in this device is not changeable.

Thanks,

Chris

Vin:5V

Vout: Channel 1=1.8V & Channel 2=1.2V,

Iout: MAX=3A

We need to online change soft start time,Can we use the register (Software Enable Device) to set the  Voltage Ramp Speed ?

HW Eanble (pin4) → set Voltage Ramp Speed(00/01/10/11)  → set Software Enable Device to 0 → set Software Enable Device to 1→soft start 

Hi,

Were you able to read section 8.4.4 in the D/S?  That should explain that the voltage ramp speed controls the speed of the change between 2 output voltages during operation.  The SS time (from enabling the device) is not changeable.

What is your SS time requirement?

The TPS628513 has a SS pin, which allows you to adjust the SS time.  Would it meet your needs?

Chris

You can use the VID pin to adjust the rate of change between 2 output voltages during operation.  I'm not sure if that is what your application needs.

When driving the VSET/VID pin, here is an app note that gives some tips for correct usage: https://www.ti.com/lit/an/slvaf64a/slvaf64a.pdf 

Chris