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LMG3411R150: LMG3411R150 and LMG3410R150 Motor driver

Carlo
Expert 7715 points
Part Number: LMG3411R150
Other Parts Discussed in Thread: LMG3410R150, TIDA-010059, TIDA-00915

Hi team, 


Good day. Our customer is interested in using the LMG341xR150 for motor driver application and has the following questions. 

"Do you have an authorized data sheet about GaN products? LMG3411R150 and LMG3410R150, first of all, I have a few questions. Recommended as a motor driver in the field of application in the datasheet of all 600V gan products. but there is no description that it can be used as a motor driver in the LMG3411R150 and LMG3410R150 datasheets. There is no obstacle in my opinion in using it, do you know the reason? Could the definition that it can be used as a motor driver be forgotten?

Apart from that, I have another important question. There are internal operational units within GaN products, you know. eg 12V - 5V buck-boost converter these require a permanent power supply. In motor drivers, (BLDC) 3 half-bridges are needed. When an H-bridge is made using GaN, the source part of the H level side is connected to the drain pin of the L level side. The GND pin that buck-boost converters need is equivalent to the h level source pin. But the problem is that (maybe the point I don't understand) when used as the h bridge, when there is a closed loop on the L level side, the power supply on the H level side will stop.

Since there is no separate GND pin from the source pin, the buck-boost side will also be closed, and it may take time to turn ON when first energized. Therefore, I do not know if it may not be recommended as a motor driver. Except for the LMG3411R150 and LMG3410R150 products, all 600V GaN products (in the data sheet) have GND pin as well as source pin. I wonder, I say, is it reserved for additional supply for buck-boost converter unit to work when the power is cut off in the source section, this issue stuck in my mind. I wonder if all 600V gan products except LMG3411R150 and LMG3410R150 are therefore available in the motor driver otherwise, is the GND pin of GaN drivers symbolic, which is the GND pin? ie is GND equivalent to source pin or has the same connection?"

We are hoping for your expertise to help our customers clarify their concerns.


Regards,
Carlo

  • 0
    TI__Genius 16390 points

    Hello Carlo,

    I'm not sure if I got the questions correctly but let me try to answer.

    1. We do have motor drive design with LMG3410R150. Please see TIDA-00915 and TIDA-010059. Customer can order sample board for evaluation.

    2. The high side FET's ground is referred to the switch node. When the switch node is jumping up and down due to the turn on and turn off of the high/low side FET, the high side FET's ground and signals are moving along with it. The internal buck boost converter will work for the whole duration.

    3. For the high side power supply, either isolated power supply or bootstrap supply can be used. We have more details in the datasheet. 

    4. Board's AGND can be tied to PGND of the FETs. Make sure the connection is close to the source of the FET so there is not too much inductance coupled to the AGND. LMG3410R150 EVM layout can be a good example.

    Let me know if there are follow-up questions.

    Regards,