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AC voltage sample and High-current LDO recommendation

Zirui Su
Expert 5340 points
Other Parts Discussed in Thread: AMC1311, TPS7B86-Q1, TPS7A47-Q1, LM317MQ

Hi

I would like to ask some portfolios to recommend to our customers:

1. Customer uses 6 pcs of UCC21530Q1 and 12 LDOs (TPS798) for power supply, now they want to integrate the 6 pcs of LDOs which are near to ground into one big LDO, is there any recommendation due to their requirement?

2. Their power level is about 11kW OBC so they use 3-phase PFC topo, now they want AC voltage sample on the input stage, which device could I recommend to them for AC voltage sampling?

3. Are there any single isolated power supply recommendation for isolated voltage sampling for device like AMC1311?

  • 0
    TI__Intellectual 1200 points

    Zirui,

    In response to your question #1 about combining the 12 TPS798s into 1 LDO I have a few questions which will help us provide the proper recommendation. Let me know if you can help respond here. 

    1. Are all 12-TPS798s powering 1 load in the application or do you need to drive multiple loads?

    2. Can you provide details of the load(s) the LDO is powering (expected current consumption, desired VOUT, etc)?

    3. What's the input source of the LDO? Is the LDO being powered directly from the battery? 

    My initial recommendation to consider would be our new off-battery LDO TPS7B86-Q1, which is rated for 40-V VIN and 500-mA IOUT. Do you think this could work here? 

  • 0 in reply to Blake Soileau
    TI__Expert 5340 points

    Hi Blake,

    The answers to your questions are shown below:

    1. Each of a TPS798 is powering a single channel of UCC21530Q1, they use 6 pcs of UCC21530Q1 so combining with 12 TPS798s;

    2. Their desired Vout is 25V to drive UCC21530Q1;

    3. The input source of the LDO is a power of 27V which is generated from a flyback circuit, not directly from the battery.

    I will check the current consumption and Iout requirement later, please provide me some recommendations refer to my answers above, thank you. 

  • 0 in reply to Zirui Su
    TI__Intellectual 1200 points

    Zirui,

    Assuming a Q1 grade device is needed  I would look at are the TPS7A47-Q1 or the LM317MQ devices which support the higher VOUT/IOUT needed for the application, however please note LM317MQ may not work due to the dropout limitation on the device. Let's continue the LDO selection discussion via e-mail as I see you have already reached out to me.