High supply current during scanning

[Anonymous]

I use the 20737 in central mode and see during the scan period that it draws a hefty 30mA, way too high for battery operation. Oddly during a connection with data exchange the current is much lower. Why?

The receiver should also be enabled during that period, and thus operates comparable to scanning.

Is there anything that I could do to reduce the current during the scanning period?

Currently I use 150ms window every 3 seconds. To be clear: 30mA flows during 150 ms.

I never expected that scanning would require more battery power than advertsing, so something must be very wrong. But what?

[BoonT_56]

Are you using the SIP module or SoC?

The nominal current consumption for receiving of the 20737S is 24mA as recorded in the datasheet. While your scan interval

is quite wide, I suggest that you shorten your window to probably a third of it. That may recover some battery life. Are you also

powering some other peripheral device?

[Anonymous]

I use the Anaren A20737

No other device is connected to it.

Can you point me to the datasheet? The one I have doesn't specify the scan

current.

I set the advertiser to 40ms, and could reduce the scan-window to 80ms. But

with that the adv isn't rcv'ed in each window. So I need to increase it a bit

more. I need a fast response when getting in the vicinity. To wait 3 o 6 more

seconds isn't an option.

But the current consumption is still a bit high for a CR2032 battery.

[MichaelF_56]

Adding kgillespie​  kieron.gillespie_1781966​ and airlinepilot_md​ of Anaren.

[Anonymous · Accepted solution]

Hi Bartels,

The link to the data sheet is here : https://atmosphere.anaren.com/wiki/images/e/ec/ANN-20737x.pdf

Page 33 of 45 lists the current consumption numbers however these are only true using a DC-DC converter. [bringing the volatge down from 9v to 3V].

WRT to the scan current, the RX mode current consumption is about 25mA [Bluetooth Smart Modules | Anaren Atmosphere ] and if you can send us your schematics at atmospehre@anaren.com, we can review it for the excess current draw.

I would also like to point out the various current consumption numbers that were tested by Anaren and available in the post here : Power Consumption Estimates | Anaren Atmosphere

In order to lower the current draw, we suggest using a buck boost converter  such as the TPS62732 to operate the module at 1.8V instead of 3.3V, which would help in extending the battery life.

Hope this helps.

MD