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TIDA-020031: External 5V and 12 V Supply

Amish Shirsat
Prodigy 30 points

Part Number: TIDA-020031

Hello, 

I am referring TIDA-020031 for our requirement of 3.3kW DC DC converter. In mentioned schematic, there are two auxiliary power supplies i.e. 5 V and  12 V (For High Side Gate Driver and Low side gate driver, main chip respectively). So, my question is that

1) why do we require 2 separate supply for main chip, low side and high side driver? 

2) Can we use output battery as a power supply in this schematic ? 

 

  • 0
    TI__Intellectual 2291 points

    Hello, I am not sure if I understand this question correctly. Let my answer.

    ad 1)

    The gate driver requires isolated bias supply. The switch node between QA, QB and QC, QD jumps between 0 to 400V. The control signal (PWMs) for the driver has to be isolated. The controller supply voltage comes from 5Vs that is referenced to the converter low-voltage output (12V). This also means that this design requires some voltage on the output (battery, external supply) to operate. There is no HV startup.

    2)

    Do you mean conversion from 12 to 400V instead of 400 to 12V ? This design is unidirectional, from 400 to 12V. It is not possible to simply change the current flow without design changes.

    Best regards, Jiri

  • 0 in reply to Jiri Panacek85
    Prodigy 30 points

    Hello Jiri,

    1) Ok, so you mean that it requires a external supply i.e. shown in first image of 5V for start up operation.

    2) I meant that, can we use battery output for the start up operation of control circuit? so that we don't have to use external supply for control circuit. I think in TIDA-020031 is using 12VOUT as a supply to UCC28951 as shown in following figures. (12Vout is the voltage at battery)

  • 0 in reply to Amish Shirsat
    TI__Intellectual 2291 points

    Hi Amish, your understanding is correct. You can use the 12-V battery for the startup as long as the voltage does not drop below minimum operating voltage for the bias DC DC converter.