Current consumption sending iBeacons - seems to high

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Anonymous
Not applicable

Summary: Current consumption is too high - how can we reduce it?

Board: BCM920737TAG

SDK: SDK-2.0.1.7

With firmware that sends 15 iBeacon ADV packets per second, I measure this average current consumption (in mA):

1.143 +-  0.019 ( 1.124 -  1.162)

Board Configuration:

SW2 (regulator input) = USB (regulator is out of picture)

SW3 (circuit input) = COIN

SW4 1-4 = OFF (app mode)

Nothing connected to USB connector.

Power Connection:

3V power supply

V+ to coin cell holder

V- to GND on 8-pin header

Measurement:

50 ksamples/second, averaged over several 1 second windows.

Firmware attached.

1 Solution

Yes, this will work with BCM920737TAG too.

View solution in original post

6 Replies
ShawnA_01
Employee
Employee
10 questions asked 5 comments on KBA First comment on KBA

Can you attach some of the measurements from your power meter, as I don't have one to test with?

Do you really need to be advertising at +4dBm, or can your application permit a lower transmit level?

What were your power expectations?

I see LED activity every 30 seconds along with the debug messages:

11:04:34   AppTimer(adv, conn) stopped: 0

11:04:34   BLE_low_un_adv:timer(0)

11:05:04   AppTimer(adv, conn) stopped: 0

11:05:04   noAdv

11:05:04   AppTimer(adv, conn) stopped: 0

11:05:04   BLE_high_un_adv:timer(0)

11:05:34   AppTimer(adv, conn) stopped: 0

11:05:34   BLE_low_un_adv:timer(0)

11:06:04   AppTimer(adv, conn) stopped: 0

11:06:04   noAdv

11:06:04   AppTimer(adv, conn) stopped: 0

I am pretty sure you are not averaging the LED current consumption into your measurements are you?

Anonymous
Not applicable

Hi Shawn,

I'm attaching one second of measurements, including a CSV and a few graphs.

The LED current consumption is included, since I'm measuring at the input to the coin cell connector.  Do you think it's significant?  Can I remove it by removing the debug messages?

As for transmit levels, I'd need to benchmark range against our existing solution; we don't want to reduce range from what we have.   We are using the highest transmit level on our existing (non-Broadcom) platform.

Expectations: not sure, but I expected a significant reduction in power compared to our existing platform.  Instead it's about the same or higher.

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Can you take a look at the method described by JT in Re: Power consumption (see JT's answer on May 16, 2014 10:47 AM) and measure? The pictures of the current profile when advertising (in the other post) look about right, but I want to make sure that it is capturing only the chip current and not the other components on the board (some of the currents are probably on the higher side). Also make sure that no other device is scanning in the vicinity (was there a scan req/resp in one of them?).

0 Likes
Anonymous
Not applicable

OK, just to clarify - since I don't see this board in that comment:

Board: BCM920737TAG

Goal: measure current consumption of the actual module, predictive of in-product current consumption.

Procedure:

1.  Remove RD6 completely.

2.  Measure current across BC of RD6 position.

Is that right?

0 Likes

Yes, this will work with BCM920737TAG too.