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TPS61027: High current draw with this device.....

John Davies73
Prodigy 20 points
Part Number: TPS61027

Hi, I am investigating the TPS61027 to boost a 1.5v battery to 5v. I have sourced all the components as suggested in the data sheet and bread boarded the design, placing the caps as close to the pins as possible. The problem is that the no-load current draw is in the order of 40 - 80mA which is far too high and was expecting the Iq of 25uA. I have made two of these and both do the same. There are no shorts or inverted capacitors and I have the LBI tied to 0V, although this will be used in the final version. The device driven from this will draw 20 - 30mA in use.

Any ideas welcome.

John.

  • 0
    TI__Mastermind 46905 points
    Could you share the schematic? and measure the VIN, SW, VOUT waveform in no load condition.
  • 0 in reply to Jasper Li
    Prodigy 20 points

    Hi Jasper,

    I accidentally shorted the input to the output and now it is giving out 1v, so I'm currently rebuilding another circuit and will report back with my findings.

    The schematic is as per the datasheet and the components are as calculated. LBI is currently tied to 0v.

    Update.....

    Rebuilt & working. However, with no load, the supply current pulses in excess of 1mA. Please find attached waveforms & a video of the pulsing current.

    Hopefully the video will play. In .WMV format.

    John.