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TPS61261: Current output of TPS61261

Part Number: TPS61261
Other Parts Discussed in Thread: , TPS61021A

Hello, I am working on reducing power consumption of my project as well as finding an adequate power supply.  I obtained the plot above utilizing the TPS61261EVM-208 evaluation module for the TPS61261 boost converter power supply.  The voltage is measured across a 1 ohm 0.1% tolerance resistor connected between the circuits ground and the batteries negative terminal.  I am currently providing voltage via a 1.5V AA battery.  The first arrow points to the circuits sleep current (100uA), the second to when the MCU wakes up, the third is when the Bluetooth classic is turned on and the fourth is just the MCU.  The power supply is not able to supply a stable voltage when an RN42 Bluetooth classic module is powering up (voltage dips to approx 2.9V) this causes the Bluetooth module to continuously try to cycle on.  The circuit works fine when I use a power supply and provide 2V.  Is the RN42 Bluetooth module requiring too much current output for the TPS61261?  Why is this happening and what should I do to correct this issue?  Would you suggest the TPS61021A as an alternative?

Thanks for your help!

  • i think you can have the resistor in series with load to check the load current.the issue may be caused by too low input voltage. so please also measure the input voltage waveform.
  • Jasper Li,

    Thanks for your response.  I think the issue is related to the lengths of wires that I am using to connect the evaluation boards to my circuit.  I noticed some large differences in current consumption and input/output voltage waveforms when changing these wire lengths.  Keeping them as short as possible during the breadboarding phase should help achieve more realistic results when placed on a PCB.


    Trevor Haanstad