LM25143-Q1: LM25143-Q1 TI P Spice simulation error

Hi Rahil,

Thank you for your reply. I have used the same file and modified as per my circuit of single output 2 phase converter. Second channel initially turning on and going off, first channel is working. May be some initial condition issue, but what i have to consider for initial condition to follow.

Regards

Rayees K.E

Hi, 

Thank you. I have seen two simulation pages in the TI reference schematics like startup and steady state. Which one i have to follow?

In my schematics I have connected the FB1 to voltage divider to make 13V and FB2 to GND as per recommendation, after that i have just tried by shorting the FB2 to FB1 instead of GND, that time both channels are providing the pulse, but the pulsed are not correct.

Regards

Rayees K.E

Hi,

Thank you for your clarification, i will use the steady state for simulation, currently i  have used the startup. 

Can you please confirm, for 2 phase operation with variable voltage what will be the connection for FB2, whether its need to be grounded or shorted with FB1. FB1 is connected with the voltage divider.

Regards

Rayees K.E

Hi Rahil,

Yes, i have followed same as above, the FB1 i have used with voltage divider for setting 13V output, FB2 connected to GND as per the datasheet for 2 phase operation,

Regards

Rayees

Hi Rahil,

I have tried all the way, but channel 2 is not working, can you have a look in to my simulation file to understand the problem. I can share you the simulation file.

Regards

Rayees K.E

Hi Rahil,

With further simulation. i have observed that, if I am making 2 separate Individual output by setting13V its working, but the simulation is not working if I am running in 2-phase simulation mode. I feel this may be a model issue.

Regards

Rayees K.E

Hi Rayees,

To clarify, dual 13V output works fine on simulation but single output does not? 

Can you send me your PSpice files? 

Regards,

Rahil

Hi,

Yes, when simulating for Dual output both channels are working, i have tried like both channel 5V, 3,3V and 13V. But, when i am shorting the output and running for single output interleaved operation second channel is not providing any gate waveform.

One more issue i have seen like when i am operating below spec, i have seen some problem in the gate waveform, 

Input 15V or 16V, Output 13V Each output, Individual channel output current 30A

below waveform i have observed,

You can see the pulses are not equal.

what will be the issue here.

MODE connected to GND

DITH---VDD

DEMB---VDD

2 PHASE Buck 13V Scheme.pdf

Regards

Rayees K.E

Hi Rahil,

As per my further analysis, below are the observations,

Simulated as Dual output (5V output both channel) ---Its working  (FB1 and FB2 connected to GND)

Simulated as Daul output (5V output both channel)---Its working (Connected Divider resistor to make 5V output)

Simulated as Dual output (Channel-1 5V and Channel-2 13V output by Divider)---Pulse is not proper,, its overlapping,

observed the gate waveform of 13V channel as below, other one is ok.

Below 10V waveforms are observed ok, 10V and above waveform is like above.

After that simulated in 2 phase mode by shorting both the output, 5V output is ok, 10V and above the channel-2 pulse not available and channel 1 pulse is like below,

Channel-2 as below,

Please help me to find out the problem.

Regards

Rayees K.E

HI Rayees,

I will look into this and get back to you.

Regards,

Rahil