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TPS62203: Consumption of the component at 0.05 mA load current

BUSO Olivier
Intellectual 260 points
Part Number: TPS62203
Other Parts Discussed in Thread: MSP430G2553, TPS62745

Hello,

On my IOT system I need 6v supply with 4 AA battery. This system is based on MSP430G and it must 3.3V powered . When my system is "sleeping" only the MSP430 is powered and it consumption is 0,05 mA , in this state all other part of the board isn't powered. The system stay in this state very long time . My goal is to change batteries less often as possible. My question is, how much Amps is the consumption of the TPS62203 when the cunsumtion of the MSP430 is 0.05 mA ? It diffcult for me to see it on the datasheet

Thanks for your help

Regards

  • 0
    TI__Expert 3645 points
    Hello,
    according to the described scenario, you can see in figure 6 of the datasheet the efficiency curves for the load current (0.05 mA), the output voltage (3.3 V) and the input voltage (3.7 V and 5 V). Do you want to calculate the total power dissipated by the IC?
  • 0 in reply to Alfonso Furio
    Intellectual 260 points

    Hi Alfonso,

    Figure 6 gives approximatively an efficency of 65% for 0.05 mA at 5V , but my question is , what is the total consumption in mA when the output current is 0.05 mA , TPS62203 included ?

    At 6V Vin I assume that the efficency is lower , if we take as hypothesis the efficency is 50% , the consumption wil be 0.1 mA . But what should I to add to know the TPS62203 input current (in the recommended operating conditions) ?

    ( I don't know if consumed curent by the power dissipated is inculded in the efficency or not)

    Regards

    Olivier

  • 0 in reply to BUSO Olivier
    TI__Intellectual 2605 points
    Hi Olivier,

    For given operation conditions (input voltage VIN, output voltage VOUT, input current IIN, output current IOUT) the efficiency eff is defined as eff=POUT/PIN, where POUT=IOUTxVOUT is the ouput power and PIN=IINxVIN is the input power.

    In your example case (IOUT=0.05mA, VOUT=3.3V, VIN=6V, assumed efficiency at those conditions eff=50%), the input power will be: PIN=POUT/eff=IOUTxVOUT/eff=330uW. This will translate into: IIN=PIN/VIN=0.055mA.

    Best regards,
    Yann
  • 0 in reply to Yann Ducommun
    Intellectual 260 points

    Hi Yann,

    Sorry, but my informations above are wrong. Behin the TPS62203 there is a MSP430G2553 connected and when it is in LPM3 mode ,  it consumption is 1 µA ! In the chart of the TPS62203 , there is no informations for very low current . Could you tell what would be the total consumption of the TPS62203 in this conditions.

    My apologies

    Regards

    Olivier

  • 0 in reply to BUSO Olivier
    TI__Intellectual 2605 points
    Hi Olivier,

    At those very light load conditions, the quiescent current Iq of the device (Iq=15uA typ. for TPS62203) will be a big contributor to the total consumption. Please read following app note treating this subject in detail:
    www.ti.com/.../slyt412.pdf

    If best efficiency at those load conditions are important for your application, we have better suited devices with much lower Iq in our portfolio. Please check for example TPS62745 (Iq=400nA typ.)

    Best regards,
    Yann