This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LMG1210: LMG1210 Hysteretic Controller with TLV3603

Part Number: LMG1210
Other Parts Discussed in Thread: TLV3603, TLV3601

Hello,

I am simulating a hysteretic controller in TINA with the gate driver being the LMG1210 and hysteretic comparitor being TLV3603.  I am using the TLV3603 to send in 1 PWM input to the LMG.  I understand how the TINA LMG referance design works and adapted it for 1 PWM input.  When I change it from a voltage source input PWM to the comparitor's output it has a convergance error centered around the bootstrap diode.  I don't understand why, any ideas?  Attached is my sim too.

Also a few more things I wanted to check, since I have become very familiar with the LMG datasheet and sim.

  • Which pin in the sim coresponds to NC1 from the data sheet?
    • NC_1 is tied to ground in the TINA model and do not understand why because if it is NC1 that the data sheet is refereing to it shoud be tied to HS.
    • Also the TINA sim only has 3 NC pins instead of the datasheets 4, bit confused here
  • How can Vin in the TINA sim take in 50V (default model I downloaded) the datasheet rating for Vin (absolute max) is 20V
  • There seems to be a descrepancy between VDD and VCC from the TINA sim and the datasheet, just wanted to check that they are indeed the same thing

LMG1210 with TLV3603.TSC

Appreciate the help,

Patrick

  • Hello Patrick,

    I spent quite a while trying to make this converge, but couldn't. Something about the interaction between the TLV output and the PWM input seems to be causing problems, given that I can isolate the PWM circuit and it works fine. I also tried using different op-amps, and all of the ones I tried worked. I tried a bunch of things like RC filters and VCVS but couldn't get it to converge. 

    As for the questions:

    Which pin in the sim coresponds to NC1 from the data sheet?

    I wouldn't worry about the NC pin connections. In most cases, we wouldn't add functionality to the NC pins in the model as it could cause problems and increase simulation time. All of the NCs are likely true NCs and thus the connection doesn't matter. I would connect them all to ground. 

    How can Vin in the TINA sim take in 50V (default model I downloaded) the datasheet rating for Vin (absolute max) is 20V

    It adds a surprising amount of simulation time to add upper limits, especially if we put them on all of the pins. Simulations like this aren't good for modelling thermal dissipation or damage from exceeding absmax. In this case, since Vin feeds into an LDO, the simulation works fine with the 50V VIN; and it doesn't have to worry about the ratings of the internal LDO or power dissipation. 

    There seems to be a descrepancy between VDD and VCC from the TINA sim and the datasheet, just wanted to check that they are indeed the same thing

    I also checked and they are the same (measured the pin and got 5V form the LDO).

    As for the simulation, I will send this thread to the team responsible for the TLV3603 to see if they can figure it out. I know these comparators should work with these drivers based on these documents:

    https://www.ti.com/lit/ug/snou183/snou183.pdf

    https://www.ti.com/lit/an/snoaa82/snoaa82.pdf

    but it is always nice to have simulations. 

    Best of luck,

    Alex M.

  • Hi Patrick,

    Thanks for your question. I agree that there seems to be some issue between the interaction with the TLV3603 and the PWM input in the LMG1210. The TLV3603 circuit alone sims properly. Unfortunately I am not sure what is causing this issue.

    What you can do is tweak the circuit analysis parameters in TINA. You may need to play around with the values to get better results. The only issue is there may be inaccuracies in the output. Let me get back to you tomorrow to see what gives me the best result

    Chi

  • Sounds good really apreciate, it Chi.

  • Hey Alex thanks a lot for the in depth analysis!  This helps a ton and just got a dev board for the comparitor to test with the lmg dev board, so hopefully it all works, Patrick

  • Patrick,

    I am still figuring out the issue with TLV3603 which may take some time. As a temporary fix, I replaced it with the TLV3601 (same device without the LE/HYS pin) and I am having it emulate a 35mV hysteresis just like how you're setting up the TLV3603 right now with the 100k resistor. It is able to sim now. I sent you a friend request so I can message you offline for further updates. 

     LMG1210 with TLV3601.TSC