nRF51422 power/current measurement

[10Hsin]

I have a nRF51422 dongle, and I want to know the power/current when an UART event happens.

I've read nRF51822_Development_Kit_User_Guide_v1.4 p.29 for Current Measurements, but I don't have the Motherboard, and I'm not sure if the method is suitable for nRF51422. I check the user guide due to this thread

I've also read S110_SoftDevice_Specification_2.0 14.1 and 14.2, but there were only current calculation for connection event and advertising event,

So if I want to know the power consumption, is there any formula or methods avaliable without Motherboard ?

[Øyvind Karlsen]

Hi,

Have a look at the following tutorials:

• Current measurement guide: Introduction
• Current measurement guide: Measuring current with PCA10040 v0.9.0

For the nRF51 dongle the current measurement setup is not so straightforward as there are no solder bridges, you could however attempt to use the oscilloscope method as described in the tutorials. When doing this you will utilize the 3v3 and GND ports along the side of the board.

Best regards,

Øyvind

[10Hsin]

Hi Øyvind, thanks for your help, but you mean "3.3V" on the board? (see the image)

[10Hsin]

And as the nRF51- DK - User Guide v 1.0, p18 says, the measurement will become unreliable when a serial terminal is connected to Virtual COM port, so if I try to use ble_app_uart and my nRF51 dongle connected to computer, how can I measure the current correctly?

[Øyvind Karlsen]

Yes, I mean 3v3 on the board. The reason that measurements becomse unreliable when using serial is that there might be current leakage through the link if you are not careful. If you are using uart you can simply leave it unconnected while measuring as it will continue transmitting.

[10Hsin]

Thanks for your response, it really helps.