PSPICE-FOR-TI: PSPICE

Part Number: PSPICE-FOR-TI
Other Parts Discussed in Thread: LMG5200, BOOSTXL-3PHGANINV

Hello. Help me.

This is a 100V schematic of the LMG5200 of the BOOSTXL-3PHGANINV substrate.

I want to analyze this circuit, but PSPICE has only 80V of LMG5200, so I want to create a circuit as shown in the image above.

So how do you make PGND in the red frame of the image on PSPICE?

Best regards..

Tosi

  • Hi Tosi, 

    I believe PSPICE gives the option to use different ground symbols under Place -> Ground.  You can use these and then connect them together on the schematic. 

     The BOOSTXL-3PHGANINV uses these two grounds to separate the signal ground from the noisy power ground. In the schematic, the PGND and GND are tied as shown below:

    Regardless, for simulation purposes, different grounds are not required to be used to create a functioning system. It will have no impact on the simulation.

    Best Regards,

    John

  • Thank you very much for the reply.

    Now, regardless of the purpose of the simulation, you don't need to create a GND system. Because it does not affect the simulation.

    Another question.

    When simulated the circuit as shown in the image above, I think that it will not work unless the power supply is placed in the red frame.

    Is the VBUS in the red frame above a 100V power supply in the image on the right?

    What is the power supply of the left red frame?

    As I mentioned last time, this circuit is boostxl-3PHGANINV.

    I'm sorry for the confusing sentences. Thank you and point out.

    Tosi.

  • Hi Tosi,

    The VBUS voltage can range from 12V to 60V, as that is the voltage the inverter is rated for. The "100V" is referring to the voltage rating of the 3.3 uF capacitor between VBUS and GND.

    Please let me know if I understood your question correctly.

    Best Regards,

    John

  • Hi John thanks for replying.

    Then, as described in the first image, it is okay to say that the value between 12V and 60V is good.

    Then, the question is, is the symbol of the power supply correct in the second image?

    Eventually, PWM will be input to this circuit to observe the strained waveform. I don't ask many questions at once. However, I will ask you questions little by little, so thank you for your answer. I'm waiting for a reply.

    Tosi.

  • Hi Tosi,

    Those are the correct power supply symbols to be used for the VIN and VCC pins. However, the connections are not correct - the positive end of the supplies must be connected to the pins and the negative end should be referenced to ground. 

    Additionally, you will need two complementary PWM signals for the HI and LO inputs. There will be shoot-through in the half bridge if the same signal is used for both HI and LO.

    Best Regards,
    John 

  • Thank you for your reply.

    I also tried to connect GND by correcting the connection between the VIN pin and the VCC pin in the image above. Is this the correct answer?

    The blue frame is currently under production because it inputs a PWM source. Do you want to place GND here as well?

    Last time, John said, two auxiliary PWM signals are required for the HI and LO inputs. If both HI and LO use the same signal, a shoot-through occurs in the half-bridge. I would be happy if you could tell me more about .

    Thank you very much, really always.

    Tosi.

  • Hi Tosi, 

    Yes, those are the correct GND connections that are needed to bias the VIN and VCC pins.

    The PWM signals in your schematic are currently connected to each other. This will cause a problem because the high-side and low-side FETs will be turned on at the same time, which is not desirable for any switching power supply topology. 

    Please refer to the LMG5200 Evaluation Module user's guide for more information on the connections.