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TPS61023: Current Consumption Issues

Henrique Reis
Prodigy 230 points
Part Number: TPS61023

I'm trying to understand the current consumption of the 61023.  It seems to be double what is being asked of it.

When active, our load will draw about 30mA.  But the current going into the 61023 is around 60-70mA

When our load goes into power save mode, it draws 10uA or so......but the 61023 will fluctuate up to 12mA, down close to 100uA, and just doesn't seem to settle.  But it always bounces in the mA range.(1-12mA)

The inductor we are using was one suggested by the design software.  PN: VLS3012HBX-R47M

The input voltage will be about 2.5V, we need 3.7V out and to be able to supply 0 to 1A of current

  • 0
    TI__Mastermind 34231 points

    Hi Henrique,

    The tested efficiency result looks a little bit low. For a 30mA load current, the efficiency is around 63%. 

    Have you tested the full load efficiency at 1A?

    How do you measure the input current and output current? We recommend using DMM to measure the current as normally the measured current shown on power supply screen is not so accurate. 

  • 0 in reply to Zack Liu
    Prodigy 230 points

    Our full load won't be more than 730mA,  I have not tested it at that level yet.  If it ever hits that, it is only for a few seconds.

    For me, the biggest concern is efficiency when the system is near the lower end of the current scale.  Especially when the cell module is sleeping and only consuming 10-50uA.  I don't want to turn off the 61023 as we need to keep power to the cellular module in order to keep connected to the cell system.  The module wakes up every 80 seconds to communicate for a second, then falls asleep again.

    The way we measure the input and output current is with 1ohm resistors and the voltage drop across them.

  • 0 in reply to Henrique Reis
    TI__Mastermind 34231 points

    Hi Henrique,

    Below is the TPS61023EVM efficiency curve at Vin=1.8V, Vout=3.6V. You could see efficiency is around 92% when the load current is 30mA. We don't have the data of 10-50uA. 

    Below is the possible reason that your board efficiency is lower:

    1. The inductor you are using  VLS3012HBX-R47M DCR is 27mohm and value is 0.47uH. TI EVM inductor XEL4030-102MEB DCR is 8.9mohm and value is 1uH. So the EVM's inductor DCR loss and AC loss is lower than yours.

    2. Can you share the layout? If possible, please share it. Also, in order to test the efficiency correctly, always measure the input and output voltage close to the TPS61023 input and output capacitor (the 1ohm current sense resistor has voltage drop).

    3. When load current reaches to 0.73A. Input current is 3.7V*0.73/2.5=1.1A. The voltage drop at input current sense resistor is 1.1V, may affect the normal working the device. Please short the input and output current sense resistor for formal production.

  • 0 in reply to Zack Liu
    TI__Mastermind 34231 points

    Hi Henrique,

    Any update about this case?