Using PPK to measure high-side current consumption of a battery-powered device

[tmeeusen]

 

Dear,

We would like to have a setup where we want to measure the current consumption of a battery-powered device with an NRF-52840 chip:

• The battery is a Li-Ion one with a capacity of 60mAh. 
• We can do both high and low-side current measurements on our breakout board. 
• We have also a Nordic-DK-NRF52840 available. 

Is it possible to configure the PPK2 for this setup in ampere mode? If so, how should it be connected to the DUT?

In source mode, I was able to measure the power consumption. However, it would be interesting to measure it with the battery in place in ampere mode. 
In ampere mode, we were able to measure the power consumption at VDD. However, is there a way to measure here as well the current delivered by a LIPO for instance? 

Thanks in advance for your answer. 

Kind regards, 

Tom 

[helsing]

Dear Tom,

Yes, it believe this should be possible. I will get back to you later today or tomorrow with details.

Best regards,

Håkon

[hmolesworth]

This shows how to measure, assuming I understand your question. With a common Gnd, insert the PPK2 between the battery high-side and the circuit thus:

// Resistor Rc for current sense is 1k0 in parallel with onr or more of 110R, 11R0, 1R0 and 0R051
//
//              <- +ve Supply to DUT From VOUT                               External Battery +ve To VIN
//             +------------------------------+                             +-----------------------+
//             |                              |                             |                       |
//             |              +---------+     |                             |     +---------+       |
//             |              |     GND |     | VOUT                   VIN  |     | GND -ve |       |
//   +=========O=========+    |    +====O=====O=============================O=====O====+    |       | Battery
//   |        Vdd (+)    |    |    |    |     #----+                        |     |    |    |       | + 3 volts
//   |                   |    |    |    |     |    |Rc        AMPERE \      |     |    |    |     +-O-+
//   |                   |    |    |    |     |   +++                 \     |     |    |    |     |   |
//   |                   |    |    |    |     |   | |   +-----------O  O----#     |    |    |     |   |
//   | Device Under Test |    |    |    |     |   | |   |                   |     |    |    |     |   |
//   |       DUT         |    |    |    | 120k|   | |   |                   |120k |    |    |     |   |
//   |                   |    |    |    |    +++  +++   |   \  SOURCE      +++    |    |    |     |   |
//   |                   |    |    |    |    | |   |    |    \             | |    |    |    |     +-O-+
//   |                   |    |    |    |    | |   +----#--O  O-- PPK LDO  | |    |    |    |       | Gnd (-)
//   |                   |    |    |    |    | |                           | |    |    |    +-------+
//   |                   |    |    |    |    +++                           +++    |    |
//   |                   |    |    |    |     |                             |     |    |
//   |                   |    |    |    |     #-- VDUT                VIN --#     |    |
//   |                   |    |    |    |     |  Sense                Sense |     |    |
//   |                   |    |    |    |    +++                           +++    |    |
//   |                   |    |    |    |    | |                           | |    |    |
//   |                   |    |    |    |    | |                           | |    |    |
//   |                   |    |    |    |    | |                           | |    |    |
//   |                   |    |    |    |    +++                           +++    |    |
//   |                   |    |    |    |     | 30k                     30k |     |    |
//   |                   |    |    |    +--#--+                             +--#--+    |
//   |                   |    |    |       |                                   |       |
//   |                   |    |    |     =====      <<== Common Gnd ==>>     =====     |
//   |                   |    |    |      ===           (Common -ve)          ===      |
//   |        Gnd (-)    |    |    |       =                                   =       |
//   +=========O=========+    |    +===================================================+
//             |              |     PPK-II
//             +--------------+

Remember to turn on the slider on the App after setting Ampere Mode - see my notes ppk-2-not-passing-through-external-power-in-amp-mode

[helsing]

Thank you Hugh.

Tom, let us know if you need any more details on how to set things up.

[tmeeusen]

Thank you all, that worked out nicely! 

Kind regards, 
Tom