Power consumption question

RE: Power consumption question

haakonsh — Tue, 27 Feb 2018 13:44:56 GMT

Hey Jay, I need you to electrically isolate the nRF52 from the rest of the circuit and re-run your measurements. We need to determine if the current consumption is due to the nRF52 or external circuitry before we proceed. I have experienced painful debugging sessions where I ultimately traced an increased current consumption to a faulty MOSTFET on a custom board.

I usually start by cutting traces to the most suspecting circuit. In this case it's the external IC.
You might want to write some dummy code for the interaction between the nRF52 and the external circuits, so your application wont crash.

RE: Power consumption question

hmolesworth — Thu, 22 Feb 2018 16:04:05 GMT

I wonder what supply voltage you are using? 1.9 volts consumes significantly less power than 3 volts, and a regulator such as the TPS62732 lets you put it into Bypass mode when asleep (with virtually no Iq) to achieve sub-2uA consumption with RTC running so Off mode is not mandatory.

RE: Power consumption question

hmolesworth — Thu, 22 Feb 2018 15:56:24 GMT

If using the Nordic Serial Port profile note that this enables the serial hardware USART on the (eg) nRF52832. Where this USART is not required, turning the USART off after pushing out some startup messages reduces power consumption by around 1mA (ie. a lot). Use app_uart_close() to turn off. I see around 1.5mA static consumption while connected over BLE when running multiple peripherals both on-chip and off-chip, but it took significant effort to get there.

RE: Power consumption question

Jay — Thu, 22 Feb 2018 14:41:07 GMT

its a custom board, it also has a ICM20948 gyro/accel sensor and a flash memory chip. but when i disable ble the power consumption drops to 1.6mA thatsstill a lo but clearly the most part before was ble

RE: Power consumption question

haakonsh — Thu, 22 Feb 2018 13:22:17 GMT

Is the 1ohm shunt populated at R6?
What peripherals and gpios are you using?

RE: Power consumption question

Jay — Thu, 22 Feb 2018 13:00:30 GMT

I used a 1 ohm schunt resistorand a this current shunt monitor: http://www.ti.com/lit/ds/symlink/ina216.pdf

Also I can confirm that unplugging the debuger cable and power cycling the board does no solve the issue.

RE: Power consumption question

haakonsh — Wed, 21 Feb 2018 11:41:57 GMT

How exactly have you measured the current consumption?
we need details.

RE: Power consumption question

Jay — Tue, 20 Feb 2018 16:00:06 GMT

No it shouldn't have been, but I wil try with the cable entierly unplugged just in case.

RE: Power consumption question

Turbo J — Tue, 20 Feb 2018 15:46:23 GMT

Is the debugger still connected via SWD?