Current Consumption in Ble5 LE Coded PHY

RE: Current Consumption in Ble5 LE Coded PHY

Madhukeshwar — Tue, 17 Sep 2024 07:56:40 GMT

Hi,

Thanks for the reply, understood it now.

Madhukeshwar

RE: Current Consumption in Ble5 LE Coded PHY

Hung Bui — Tue, 17 Sep 2024 07:35:34 GMT

Hi,

[quote user="Madhukeshwar"]The average current depends on both the total charge and the time duration. average current is inversely proportional to time. so, if the time interval is increased average should also decrease right?![/quote]

It's only correct if you continuously transmit all the time (radio always active) then the switch between 1Mbps and CODED PHY doesn't change the power consumption.
However, in common use cases with BLE the radio is inactive most of the time. So when you switch to CODED PHY the radio has to be active 4 times longer on the same connection interval. This will increase the average current consumption. Think of something like this:

RE: Current Consumption in Ble5 LE Coded PHY

Madhukeshwar — Tue, 17 Sep 2024 05:31:22 GMT

Hi,

[quote userid="2121" url="~/f/nordic-q-a/114756/current-consumption-in-ble5-le-coded-phy/502622"]Why would average current should be the same ?[/quote]

The average current depends on both the total charge and the time duration. average current is inversely proportional to time. so, if the time interval is increased average should also decrease right?!

[quote userid="2121" url="~/f/nordic-q-a/114756/current-consumption-in-ble5-le-coded-phy/502622"]When you use more time to send the same data, the radio has to be active longer hence draw more current.[/quote]

Yeah, I agree to this point. but Total consumption may increase. how does it contribute on average current?

RE: Current Consumption in Ble5 LE Coded PHY

Hung Bui — Mon, 16 Sep 2024 13:39:11 GMT

Hi again,

Could you elaborate more on this ?

[quote user="Madhukeshwar"]when take the average current, both Ble 5 CODED PHY and Ble 4 average current should be same.[/quote]

Why would average current should be the same ? When you use more time to send the same data, the radio has to be active longer hence draw more current. As I said, it's the trade off when you have more range with CODED PHY.
Please show us more data of your measurement.

RE: Current Consumption in Ble5 LE Coded PHY

Madhukeshwar — Mon, 16 Sep 2024 12:53:08 GMT

Hi Hung Bui,

[quote userid="2121" url="~/f/nordic-q-a/114756/current-consumption-in-ble5-le-coded-phy/502611"]meaning any packet you send in normal 1Mbps is transmitting at 8 times longer. This explain the higher power consumption you have. [/quote]

yeah, it takes more time to transmit the same amount of data with a longer range right!. when take the average current, both Ble 5 CODED PHY and Ble 4 average current should be same. but we got almost double.

so we wanted expected current consumption for Ble 5 CODED PHY.

RE: Current Consumption in Ble5 LE Coded PHY

Hung Bui — Mon, 16 Sep 2024 12:43:41 GMT

Hi Madhukeshwar,

When you use Coded PHY S=8 each bit of data is transferred as 8 symbols, meaning any packet you send in normal 1Mbps is transmitting at 8 times longer. This explain the higher power consumption you have.

It's the trade off of having a longer range when using CODED PHY.
Note that with BLE 5.x (or 6.x) you can still use normal 1Mbps instead of CODED PHY so you shouldn't have any current consumption change compare to BLE v4.x. If you want to reduce current consumption, you can consider using 2Mbps PHY. It would require half of the time to transmit the same data. The trade off, of course, is shorter range.