the power consumption of CC2540 in connectable mode and advertisement mode

jie liu36614

Other Parts Discussed in Thread: CC2540, ASH

I have a board of CC2540. It's basically the Keyfob without the accelerometer. I found that the current consumption when the board is in connectable mode is around 0.85mA and the current when it is advertising is around 0.52mA. Could someone tell me why the current consumption is higher in connectable mode? I think in connectable mode the chip is listening and it should consume less power when it advertises with the RF fully on. And current consumption of connected and connectable mode seems to be the same. Is this normal? I don't have keyfob right now so I can't verify it on the reference board. It would be nice if someone could do the experiment for me. Thanks ahead.

over 12 years ago

0 J Lindh over 12 years ago

TI__Guru 57865 points

Hi Jie,

A Central device will typically draw more power than a Peripheral device. This is because during scanning, the RX window is very much larger than the small TX peaks that the Peripheral device generates during advertisements.

Typically, during advertisements, TX peaks are around ~130us (reference) whilst scanning can run almost continuously or with at least RX peaks of milliseconds. The scanning consumption can be minimized by reducing the scan window and scan interval but it will be resulting in a less chance to capture an advertiser.

I hope this answered your question.

Best Regards

0 jie liu36614 over 12 years ago in reply to J Lindh

Intellectual 270 points

so this is actually a situation that the longer the RF is working the more power it requires. Thanks a lot for your explanation.

0 J Lindh over 12 years ago in reply to jie liu36614

TI__Guru 57865 points

Hi Jie,

Correct, as processing is ~6-8mA and RF is 14-27mA (depending on chip)

0 Hsa S over 10 years ago in reply to J Lindh

Expert 2570 points

Dear Mr Joakim, I read your explanation well. In my case, I measured the Tx and Rx peaks, these are almost the same what you mentioned, but when I measure the total current consumption (shows in DC power supply by which I am applying 3.0v DC to device) is around 2mA, which is very high for my application. please guie me accordingly~ Thanks /Ash

0 J Lindh over 10 years ago in reply to Hsa S

TI__Guru 57865 points

Hey Ash,
Application note AN092 might help you further in your investigation.
www.ti.com/.../swra347a.pdf

Best Regards
Joakim

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the power consumption of CC2540 in connectable mode and advertisement mode