Unwanted reboots NRF9160 - Brownout?

RE: Unwanted reboots NRF9160 - Brownout?

Kazi Afroza Sultana — Fri, 01 Mar 2024 10:33:18 GMT

Hello,

This is our schematic where VDD_GPIO is connected to VDD.

You can set the VDD voltage to 1.8 V (default) or 3 V with SW9. Running 3 V GPIO with heavy load may degrade the LTE RF performance.

The I/Os are supplied via VDD_GPIO pin as shown in figure above. VDD_GPIO pin supports voltage levels within range 1.7 to 3.6V. VDD_GPIO should be applied after VDD has been supplied.

And the capacitors values are in accordance with the schematic. What was the motivation to change it?

RE: Unwanted reboots NRF9160 - Brownout?

Achim Kraus — Sun, 25 Feb 2024 11:13:22 GMT

Just to mention, the nrf9160-feather v5 is using the new values and runs stable in my experience.

RE: Unwanted reboots NRF9160 - Brownout?

charleshaf — Fri, 23 Feb 2024 20:58:22 GMT

I'm also seeing a lot of brown out behavior. Using the Actinius Icarus boards. Using 2x ER34615 batteries so should be plenty of amperage out of them.

RE: Unwanted reboots NRF9160 - Brownout?

benna — Thu, 22 Feb 2024 08:42:49 GMT

Hi Kazi Afroza Sultana ,

Any update on this?

Thank you

RE: Unwanted reboots NRF9160 - Brownout?

benna — Wed, 14 Feb 2024 07:41:28 GMT

Hi,

Any updates on this?
This reboot behaviour is holding us back from releasing.

We've been reviewing the schematics and we've noticed two things:

C10 on VDD2 used to be 4.7uF (as on our board), now is 47uF
C7 on IO_SUPPLY (DEC0) used to be 47uF (as on our board), now is 4.7uF

RE: Unwanted reboots NRF9160 - Brownout?

benna — Thu, 08 Feb 2024 09:27:12 GMT

Hi,

I've got myself an analog discovery and hooked it up to the 1.8VDC rail from my board & to VDD (3.5V from a PPK2 in this case).

You can see that the 1.8VDC power rail is going bananas when sending a message over LTE, which will be the problem.

We have a custom board but I was told that the schematic was verified by Nordic.

Any ideas what can be causing this? Some capacitive coupling?
All capacitors are according to the datasheets.

I know this is a hard to answer question without the board or any more information, but any ideas would be very welcome :)

RE: Unwanted reboots NRF9160 - Brownout?

benna — Thu, 01 Feb 2024 12:05:36 GMT

Hi Kazi Afroza Sultana ,

Thanks for the reply and information!

My description of the power supply wasn't really complete:

LiPo is connected to VDD of the nrf9160
1.8V via the LDO is used for VDD_GPIO

Does the modem use the power supplied directly by the LiPo (VDD) or does it use the 1.8V (VDD_GPIO) which is supplied via the LDO?

A voltage drop on the 1.8V would clarify also some other phenomenon's, like an accelerometer resetting, but it would be nice to know the reason ofc of this drop.

RE: Unwanted reboots NRF9160 - Brownout?

Kazi Afroza Sultana — Thu, 01 Feb 2024 11:55:10 GMT

Hello,

If the register is zero, then it a power on reset.

'' are using an LDO rated for 150mA at 1.8V, powered by a LiPo.''

For extremer operating condition, peak current consumption of modem is around 430 mA. If your LDO is rated for 150mA , then it needs more voltage to operate so, there would a chance to go below operating voltage which triggers to brown-out reset.

source: https://infocenter.nordicsemi.com/topic/ps_nrf9160/_tmp/alta.nRF9160/autodita/CURRENT/parameters.id_current_modem.html?cp=2_1_0_4_5_0_14

RE: Unwanted reboots NRF9160 - Brownout?

Achim Kraus — Wed, 31 Jan 2024 13:00:55 GMT

> seems to contain way more information

Unless you call hwinfo_get_supported_reset_cause and check the outcome ;-). In fact I had to trick it in order to get the RESET_POR (if cause is 0 and RESET_POR isn't supported, I add it in my code.)

RE: Unwanted reboots NRF9160 - Brownout?

benna — Wed, 31 Jan 2024 10:10:54 GMT

Thanks for the information Achim!

I'm going to implement this hwinfo_get_reset_cause asap, seems to contain way more information as my current reboot log system.

PS: on resetting the device by the debugger I get 'Reset by pin-reset', so that part works.

I'll update as soon as I have more information.

Thanks!

RE: Unwanted reboots NRF9160 - Brownout?

Achim Kraus — Wed, 31 Jan 2024 06:38:24 GMT

> some spikes though of 1A

Depending on the power profiler, this may be caused by the profiler switching the range (e.g. from µA to mA or so. The power profiler kit II does so).

> it always returns 'power-on-reset'

You may check that by using the RST pin to cause an restart.

I use hwinfo_get_reset_cause that reports also RESET_PIN, RESET_SOFTWARE, RESET_WATCHDOG (I have seen all of them ;-) ).

Anyway, the questions are very valid, in fact I had the same questions on Monday but didn't open an issue. Looking forward to the answers from Nordic.