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TIDA-01505: TIDA-01505 : Lever Shifter Power Supplies

SR
Prodigy 140 points
Part Number: TIDA-01505

Hello,

We developed a PCB based on latest gerber files of TIDA-01505. In the PCB there is a 3 pin header J14 in which it is mentioned to input Level Shifter Power Supplies +20V & -5V. Please confirm whether the we need to provide these power supplies externally. The design uses WA8759-AL transformer which is specified to provide +20V & -5V on its Auxiliary windings. Whether J14 has any significance if the transformer provides these supplies?

  • 0
    TI__Mastermind 18121 points

    Dear Customer,

    External power supply is needed during startup phase. The auxiliary winding is not able to supply sufficient power during startup. The jumper is to connect to the external +20V and -5V power supply because the level shifter relies on the energy transfer from the winding to operated properly. There is no enough energy before the supply is fully on. When the output power is low, you may try to connect the R58 to the VDD node to take the power from R38, R40, R42... resistive chain. I recommend to decrease the value of this resistive chain in order to achieve sufficient power.