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TPS7A33: Using TPA7A33 to generate positive output voltage source with current sinking capability.

Chandra Prakash
Prodigy 70 points
Part Number: TPS7A33
Other Parts Discussed in Thread: TPS7A47

Hello,

My application requires having a positive voltage source(9.7V) which should be capable of sinking in 400mA of current. I could not find any such LDOs or SMPSs which have current sinking capability in this output voltage range. I found this article which suggests using a negative voltage LDO to generate a positive voltage and using the inherent capability of the negative voltage LDO to sink in current.

I was thinking of using TPS7A33 in a similar fashion to generate a output voltage of 9.7 V which could sink in current. I tried to simulate the PSPICE Model in TINA and Ltspice but it does not seem to work. I am not getting any Vout (1.8uV). Can you please tell me if it is possible to use TPA7A33 in this particluar application in this configuration. If not, can you suggest any other alternative. Thanks in advance!

  • 0
    TI__Genius 12345 points

    Hi Chandra, 

    In this scenario, it might be possible to use TPS7A33 to generate a positive rail and it will still sink current. In concept the idea seems to work. I might have to go into the lab and do a quick bench test to verify this. 

    From the TPS7A33: Is it capable of sourcing current? thread, perhaps a DDR terminator might be more suitable for your application if you need to sink from a positive rail and source from a negative rail. 

    Unfortunately, we do not have positive LDOs that sink current. 

    Typically, if a negative and positive rails are needed, a combination of TPS7A33 and TPS7A47 is suggested. 

    Best, 

    Edgar Acosta