TPS546D24S: Simulation issue

Jeff YANG

Part Number: TPS546D24S
Other Parts Discussed in Thread: TPS546D24

Tool/software:

Hi,

Our SI colleagues have encountered a problem and would like to inquire about the simulation of the TPS546D24. How should the load side be set up? Should we just connect a resistor, or is it necessary to also include a current source (40A)?

Currently, the simulation state is as attached. The output voltage results look strange and do not meet expectations.

power_3.pptx

Thanks!

Jeff

5 months ago

0 Tomoya Ide 5 months ago

TI__Genius 11396 points

Hi Jeff,

Do you know which model your colleague is using? Can you please share the link?

Thank you,
Tomoya

0 Jeff YANG 5 months ago in reply to Tomoya Ide

Mastermind 7895 points

Hi Tomoya,

Orcad Capture, it also can using Pspice model format. thanks!

Jeff

0 Tomoya Ide 5 months ago in reply to Jeff YANG

TI__Genius 11396 points

Hi Jeff,

We have 3 different models on ti.com. Which model are being used? Can you please provide the model so I can run the simulation on my side?

Thank you,
Tomoya

0 Jeff YANG 5 months ago in reply to Tomoya Ide

Mastermind 7895 points

Hi Tomoya,

The second one. Thanks!

0 Tomoya Ide 5 months ago in reply to Jeff YANG

TI__Genius 11396 points

Hi Jeff,

Either a resistor or a current source can be used, but it looks like the customer put on the current source backward. This is probably the reason why they were having a problem. Also, the current source should be applied after the output has reached a steady state.

Thank you,
Tomoya

0 Jeff YANG 5 months ago in reply to Tomoya Ide

Mastermind 7895 points

Hi Tomoya,

Let me first summarize the previous conditions. We are currently using the circuit simulation for the buck_startup in the second Transient model. We have tested several different source and loading conditions, with the simulation results attached.

DCDCsim.pptx

The current goal of the simulation is to observe the voltage drop in the subsequent application when the load draws a 40A current. For example, as shown in the figure below, the part where the voltage drops when the current suddenly spikes. This is why we previously reversed the current source to simulate the effect of drawing current. However, the results seem to deviate somewhat from our expectations. Could you please advise on how to configure the loading part to match the scenario we are trying to evaluate?

Thanks!

Jeff

0 Tomoya Ide 5 months ago in reply to Jeff YANG

TI__Genius 11396 points

Hi Jeff,

Your current source setup on the third slide is correct, but the converter seems unstable. Make sure the control loop is compensated properly with the right L and C. Use the attached Excel design calculator to help you with the design and compensation configuration.

8322.TPS546x24y_ExcelCalculator_SchematicLayoutChecklist_bodeplot_V2p2.xlsx

Thank you,
Tomoya

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TPS546D24S: Simulation issue