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TPS61130: Is this part recommended for new battery operated products?

Pål
Prodigy 30 points
Part Number: TPS61130
Other Parts Discussed in Thread: TPS61031, TPS63021, TPS61091, TPS63030, LMR62014

Hi,

We see that the TPS61130RSAR is in stock. 

Is this IC recommended for our application described below?

- 2x alkaline C cell batteries in series (1.8 - 3.3V input)
- WiFi module (ESP32)
- Board operating voltage: 3.3V
- Average power consumption: 200mA
- Peak power consumption (during WiFi transmit)): 500 mA

The device will be in deep sleep about 95% of the time. 

To maximize the utilization of the C-batteries we need a 2000uF capacitor on the output of the buck-boost to avoid early brownout. 

Thanks.

  • 0
    TI__Expert 5180 points

    Hi Michael,

    TPS61130 can be used in this application, but this device's application is a little complicated and many function is useless for you working condition. tps63021 buck-boost suitable  has only 500 pieces now, all others buck-boost are out of stock. Some boost converter TPS61031, TPS61091 can be used if input voltage can be a little smaller than 3.3V, when input and output voltage are close, the output will have larger ripple but can output 3.3V and the design is easier. 

    When use 2000uF capacitor, the system control loop will be very slow and have slow transient response. Also the start up inrush current will be larger because it will charge output capacitor first.

    Best Regards,

  • 0 in reply to Eric Yue
    Prodigy 30 points

    Are you thinking that tTPS63021 is a better fit? 

    We only choose TPS61130 because it is in stock. We are aware of the extra complication of it, and just wants to know if there are any reasons why not to choose it?

    Thanks

  • 0 in reply to Eric Yue
    Prodigy 30 points

    Will the 2000uF capacitor potentially cause a stability problem because of the system control loop?

  • 0 in reply to Pål
    TI__Expert 5180 points

    The reason I think TPS63021 better is just easier design, because TPS61130 is sepic and integrated LDO. TPS61130 can be used in this Vin, Vout and load condition as well.

    When output capacitor is 2000uF, the control loop will be slow, but I think the loop can be still stable.

    Best Regards,

    Eric Yue

  • 0 in reply to Eric Yue
    Prodigy 30 points

    Thanks

    We are then replacing TPS63030 with TPS63021. 

    Do we really need IC5 to boost the voltage to 5.25V for LMR62014XMF to supply 15V? 
    Or can we just connect LMR62014XMF directly to 3.3V? 

    LMR62014XMF delivers 80mA at 15V. 

    Thanks! 

    Schematic PDF_[No Variations] (7).pdf

  • 0 in reply to Pål
    TI__Expert 5180 points

    Hi,

    It is okay for LMR62014 to boost from 3.3V to 15V. But if battery voltage drops as low as 1.8V, LMR62014 input min voltage is 2.7V and when boost from 1.8V to 15V, the duty cycle may be as high as more than 90%, while the chip's max duty cycle is 86%.

    Best Regards,

    Eric Yue