Energy usage calculation for BLE device during discoverable mode

Dorian Hildebrandt

Prodigy 130 points

Other Parts Discussed in Thread: CC2640, CC2564

Hello

i'm starting a proyect where i need to include a Bluetooth connection (1st time for me).

The device is battery powered and has to last some years with a single battery.

I found the CC2640 which seems to be a adequate BLE chip for me.

The bluetooth connection will be used at max only 1 time per month. Someone with a mobile phone (Andoid) will

connect to my device and read out the datalog. The device will have no buttons or wired connections to turn bluetooth on.

So, my question is about the power usage of the CC2640 when he is discoverable.

I think the device should make itself discoverable 1 or 2 times per minute, am i right?

In the datasheet http://www.ti.com/lit/ds/symlink/cc2640.pdf (at page 28) are the power modes.

Is the device in "idle" mode (550 µA) discoverable? How long is the recomendation to stay discoverable?

Are there some guidelines/recommendations about this topic?

For me the 550µA during discoverable mode seems to be high, because the CC2564 http://www.ti.com/lit/ds/symlink/cc2564.pdf

on page 29 states to use only 121µA during discoverable mode. Am i reading something wrong?

I hope you can help me with his, i read a lot in diferent forums and web pages (of course http://processors.wiki.ti.com/index.php/Category:BluetoothLE?DCMP=blestack&HQS=ble-wiki )

but couldnt get a clear answer.

Best regards,

Dorian

over 10 years ago

0 Pittet Sebastien over 10 years ago

Expert 1050 points

In standby mode, with advertising every 1minutes, you can expect 3uA of mean power consumption ;)

An advertising event use 4.279mA for 4071us, and you need 5 of theses events (in my experience) to be able to connect with an Android phone. The rest of the time you will use 1.5uA.

You can see other informations here : www.ti.com/.../swra478.pdf

0 Dorian Hildebrandt over 10 years ago in reply to Pittet Sebastien

Prodigy 130 points

That was exactly what i was asking. Thank you very much.
Ok, i can verify your data, so i'm on the right way :)

Just one more question. If you say you need 5 advertising events, you have these followed immediately
one after the other, or you have some delay between them?

Thanks again.

Best regardsr

0 Dorian Hildebrandt over 10 years ago in reply to Pittet Sebastien

Prodigy 130 points

0 Pittet Sebastien over 10 years ago in reply to Dorian Hildebrandt

Expert 1050 points

Don't mention it, you can configure theses parameters in your application :

#define DEFAULT_ADVERTISING_INTERVAL    320		// Interval when device is discoverable (units of 625us, 160=100ms)
#define DEFAULT_ADVERTISING_TIMEOUT	1		// Advertising Timeout in sec
#define DEFAULT_ADVERTISING_TIMEOFF	5000	// Advertising Timeoff in msec (after timeout)

0 Dorian Hildebrandt over 10 years ago in reply to Pittet Sebastien

Prodigy 130 points

Ok, thanks.

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Energy usage calculation for BLE device during discoverable mode