ESB Tx current Spike issued

[dcjin]

The part where the current goes up is the ESB Tx section. Why does the power consumption vary every time? I am currently using a DCDC regulator and a self-made board.

The main CPU being used is nrf52833.

ESB Tx power consumption appears differently every time, with three different values: 37mA, 5mA, and 500uA

Based on the datasheet, I believe that 5mA is the normal power consumption.

I've looked at other examples in the Q&A, but is this phenomenon that occurs with DCDC regulators a common issue?

Even when I connected 1.3V direct power from PPK to the DCDC regulator pin, the issue did not go away.

What parts should I look at?

I left a response to a previous question, but it got closed so I'm reposting it again.

I used an internal DCDC regulator.

                                               

The left image shows the reference circuit of the nRF52833 DK board, and the right one shows the regulator circuit of our own developed board.

I added a DCDC regulator circuit to the DEC4 pin as a reference design like on the DK board.

When power is applied, the DEC4 pin is supplied with a voltage of 1.3V.

When comparing the energy of each spike, the total amount of energy overall is not significantly different. However, I would like this energy to always be the same.

The following picture shows the power consumption when running the same program on the nRF52833DK board.

I was able to obtain more consistent values than before.

However, an abnormal waveform appeared before Tx. Although all LEDs were turned off, I cannot determine what the value is.

I also tried changing the value of C7 from 4.7nF to 47nF, but the phenomenon remained the same.

In addition, is the abnormal ESB Tx current consumption also related to antenna matching?

[Jared]

Hi,

Can you share the the whole schematics and the part number of the capacitors and the inductors that you use for the DC/DC?

I can make the case private first if you prefer it.. 

Even when I connected 1.3V direct power from PPK to the DCDC regulator pin, the issue did not go away.

Why did you supply the DCDC regulator pin from the PPK? 

regards

Jared 

[dcjin]

The circuit diagram you requested is as follows.

I designed the DCDC regulator to be exactly the same as the nRF52833 Reference circuit.

I just thought of something after hearing your answer.

I modified something that came to mind.

After removing the capacitor from the main power supply, the current consumption of the ESB Tx was output as shown in the following figure.

The power consumption appeared to be consistent to some extent. However, despite this, compared to the nRF52833 DK board, the power consumption of the ESB Tx appears to be more than twice as high.

No LED turned on.

The power consumption value indicated in the datasheet is 4.9mA.

Actually, I think the power consumption of the nRF52833 DK board is also quite high.

Can you tell me why there is a difference of more than twice the power consumption compared to the nRF52833 DK board?

[Jared]

Hi.

Is this the whole schematic, is there anything else on your custom board such as another IC etc?

dcjin said:

After removing the capacitor from the main power supply, the current consumption of the ESB Tx was output as shown in the following figure.

Exactly which capacitor did you remove, can you specify it in the schematic? 

Are you using nRF Connect SDK or nRF5SDK?

Can you share the part number of the capacitors and the inductors that you use for the DC/DC?

regards

Jared

[dcjin]

Removed C28 and C6.

can be translated to "This is the complete circuit diagram up to this point.

C7 / 47nF : CL05F473Z05NNNB
L1 / 1uH : MLF1608E100

C19 and L7 are also products of the same subsidiary.

We are using Zephyr in nRF toolchain.

Do you have any more questions?

[Jared]

Hi,

Thanks for the sharing the part number and the schematics,

Yes, I do have a couple more questions,

1. Do you see the spikes if you disable the internal DC/DC? Set CONFIG_BOARD_ENABLE_DCDC=n in prj.conf
2. I do see that you have a several components that might be contributing to the high current consumption. For a reference, what current do you measure on your board if you flash your board with the blinky example and set CONFIG_SERIAL=n in prj.conf. Note, that you might need to change the Blinky pin to one that fits your board and make sure that any CS signal is set high to avoid that any sensors are consuming power. 

   1. Do you still see the spikes periodic spikes after flashing the blinky example,

   2. Is it comparable to what you measure on your DK?
3. Are you using the PPK2 in Source or Ampere mode?

regards

Jared 

[dcjin]

1. Here is the power consumption waveform of the ESB Tx when not using the internal DC/DC.

2. The serial is already disabled. It starts in sleep mode, and the power consumption at this time is less than 10uA.

The power consumption of less than 10uA includes not only nRF52833 but also other CPUs.

The power consumption returns to less than 10uA after the ESB Tx.

Enabling the serial consumes 300-330uA.

LED blinky consumes about 2mA of current.

This power consumption is similar to that of the nRF52833 DK board.

I don't know why the power consumption of the ESB Tx is so high.

3. I am using PPK2 to measure the power consumption in Ampere mode.

[Jared]

Hi,

Can you zoom into the TX spikes and set the resolution to 100k samples per sec. PPK can show variating spikes when it switches measurement range if you plot is zoomed too far out.

regards

Jared 

[dcjin]

I found the cause.

Hardware connection is incorrect.

When measuring power consumption with another development board, it was found that it consumed about 8mA during ESB Tx, similar to nRF52833 DK board.

Thank you