WEBENCH® Tools/TPS61256: 150mA output the output voltage drops?

Hi Antonio,

I used webench to run the simulation with the condition of Vin 3-3.5V, Vo5V, 0.5A.

Below are the simulation results:

1. Steady state:

2. Startup:

The TPS61256 may not be able to startup into full load current. During startup, the resistive load must be at least 55Ohm.

Can you let customer shows the simulation waveforms?

Hi Zack,

I have simulated the circuit shown in the attached figure, and using Rout = 30ohm then Vout collapses to 3.3V instead of being 5V.

Thank you for your support,

Marco Cilmo

Hi Marco,

Like I said in the previous post, TPS61256 may not be able to startup into full load current. During startup, the resistive load must be at least 55Ohm.
So in the EE, do you really need output connect with a 30 ohm load? Or just wait for the Vout ramping up to 5V, then the system starts to work?

Hi Zack,

in my application, the load is complex, and I can't tell you how it behaves during the startup.

Do you advise me to use another chip, or to implement a circuit to ramp the voltage up to 5V?

Regards,

Marco

Hi Zack,

I read the datasheet of TPS61253A and I also simulated it, and this device complies with my requirements.

Thanks a lot,

Marco