TPSM82903: DC input Supply fault condition

Gaurav Goyal

Part Number: TPSM82903

Tool/software:

Hi, I have been trying to simulate the online available model on the PSpice for TI software and not able to get the transient response with DC 12V input instead the model is working with pulse(0 to 12VDC) with the same configuration of the resistors on the pin of the IC. Below is the image attached of the working pulse model for the reference. Could you please help to resolve it?

Simulation Details:

Vin- 12V(DC)
Vout- 1.8V@0.7A
Switching Frequency- 2.5MHz
Transient Condition- 2.4A/230ns

Let me know if any other detail is required.

9 months ago

0 Colin Chen 9 months ago

TI__Mastermind 22001 points

Hi Gaurav Goyal,

Do you mean that if you use a DC source you can't get load transient response, but when you replace it with a pulse source, the load transient is normal?

Thanks,

Colin

0 Gaurav Goyal 9 months ago

Prodigy 50 points

Hi Colin,

Yes, This is the exact condition I am facing. Could you please check this at your end and help me to resolve this? This would be a great help. Thanks in advance.

0 Colin Chen 9 months ago in reply to Gaurav Goyal

TI__Mastermind 22001 points

Hi Gaurav,

Usually it is suggested using pulse power to avoid initialization problem in the simulation.

If you use DC power, i think you should change the IC of C5 is 12V which means set the initial voltage of C5 is 12V.

Thanks,

Colin

0 Gaurav Goyal 9 months ago in reply to Colin Chen

Prodigy 50 points

Hi Colin,

I have been trying your suggestion providing Voltage rating of the capacitor to 25V but still I am not seeing any output voltage.

Is it because of simulation transient model available on the TI website or it's an operational behaviour of the IC?

0 Colin Chen 9 months ago in reply to Gaurav Goyal

TI__Mastermind 22001 points

Change the IC of C5 to 12V don't means that the voltage rating but the initial voltage.

Thanks,

COlin

0 Gaurav Goyal 9 months ago in reply to Colin Chen

Prodigy 50 points

Hi Colin,

Could you please help to calculate the value for the same? All the parameters are provided at the first mail.

Also, Are we going to face this issue with the Physical part also?

+1 Colin Chen 9 months ago in reply to Gaurav Goyal

TI__Mastermind 22001 points

Hi Gaurav,

This issue wouldn't appear in Physical part.

As i mentioned, you should change the initial state of C5 to 12V in your simulation.

Thanks,

Colin

Power management

Power management forum

TPSM82903: DC input Supply fault condition