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External Power Supply Problem:

chinmaydixit

Hello,

When I use Debug, the program runs successfully. But when I try to connect with External Power Supply the program is not running, Also Reset is not wokring. Please guide me .

Thanks.

  • 0

    Hi,

    Can you give me more details about your setup? 

    What device are you using? Are you using a DK or custom board?

    What SDK and Softdevice are you running?

  • 0

    I have the same problem so instead of opening up a new ticket, I wanted to reply this one. I am using nRF52 DK and running ble_app_beacon demo. With USB and battery I verified the functionality. When I wanted to check with external power supply I encountered some weird behavior as listed below:

    > Initially I supplied with a 80% DC square wave, f = 10 mHz, 1.9 Vpp and 2.6 V_offset. I did like this because I did not have a DC supply so I tried to converge to it as much as possible. When input tries to reach HIGH, it can't and oscillates frantically between 3 and 2.5 V. When I stopped the the graph on the oscilloscope screen, after a few minutes, demo DID actually run, i.e. LED 1 started blinking. But did not continue to do so when I ran the oscilloscope live. I could recreate this queerness another time but not a third time.

    > After this I changed the power supply and found one that can actually give constant 3.3 V with an ability to measure current. With that, I increased the current limit up to 80 mA because the input could not rise again and current seemed to be the limiting issue. As the supply reached 80 mA the board resets itself such that there are ground spikes in the input voltage waveform.

    During these experiments only SB12 is shorted on the default configuration of the board. I think even reaching 80 mA is questionable with a simple beacon demo. Diode check yielded no shorting between the external supply pins.

    I would be glad if you could help me out with this.

  • 0

    I connected a large capacitance as suggested in this post and the board executes nicely drawing 3 mA from the external pins. Still I find the behaviour to be pretty peculiar.

  • 0 in reply to Burnie Barren
    Burnie Barren said:
    Initially I supplied with a 80% DC square wave

     So are you powering the board with a function generator? I doubt that it is able to deliver the current needed by the DK.

    Burnie Barren said:
    I increased the current limit up to 80 mA because the input could not rise again and current seemed to be the limiting issue.

     Not sure what's wrong here. Which DK version are you using? I've used the external power connector on lots and lots of DKs over the years here in Nordic and never had any problems with that. I agree that 80mA is way too much, and that 3mA is normal. But keep in mind that the ble_app_beacon demo running on the chip has a consumption in the µA range. So the 3mA you are seeing is mostly drawn by the JLink debugger chip.

  • 0

    Hi ,

    If the chip is running when the debugger is running, but not when the debugger is disconnected, it usually means that the reference design has not been followed. It could be wrong decoupling caps or a missing LF/HF crystal. Can you please post the board schematics?

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