BLE power consumption

rwel59
Posts: 75
Joined: Thu Oct 12, 2017 3:32 pm

BLE power consumption

Postby rwel59 » Wed Jan 24, 2018 4:37 pm

Setting up a network with an ESP32 master and peripheral devices communicating to the master through ble. The peripherals need to be lower power but advertising so that they are available when polled by the master. Is there any information on current power requirements with ble only and frequent advertising, i.e. at least once per sec?

I realize that I can find other mcu's designed for this scenario but would rather stick with the esp platform if possible.

iva_wearable
Posts: 4
Joined: Fri Mar 02, 2018 10:13 am

Re: BLE power consumption

Postby iva_wearable » Fri Mar 02, 2018 10:55 am

We are looking at using ESP32 for several products.

BLE will be a critical factor in the design.

We have measured the current used and see that having only BLE operating, listening to advertising only uses basically the same amount of power as WiFi does.

This includes the case where no WiFi is operating at all. It is also the case that switching to the V3.0 branch had no impact at all.

Since having BLE and draining the same amount (or similar) amounts of power as WiFi is a complete non-starter, it is critical that we determine, soon, what the situation going forward will be.

Since our products have to listen to BLE advertising all the time to receive payloads from unconnected BLE devices continuously, the ESP32 either needs to draw minimal continuous power using BLE or be able to wake-on-radio very quickly because waking-on-radio is hopeless in an environment where BLE advertising is continuous from dozens of beacons unless it is very rapid (along with sleeping time).

So, I would very much like an answer to the following questions:

1. Does the ESP32 silicon have the functionality to operate BLE using a different MAC/PHY as the WiFi (and BT Classic?) sub-system, as the schematics appear to indicate?
2. If 1. is the case, do Espressif have ongoing plans to ensure that BLE can operate alone, using BLE levels of power? I see a suggestion that v3.1 might have power settings for WiFi but we require a primarily BLE device - we selected ESP32 because having WiFi/IP stack etc. will be very useful for various other reasons (such as OTA updates) - as well as price considerations of course.
3. If 2. is not the case, will there be a system in place to allow sleep to operate with BLE such that the power budget is reduced? We see 110mA to a dev board (VROOM-32) of which only 40mA is the processor load, the rest is present only when BLE is used.
4. Is it likely that the processor silicon will use less power in a future iteration? e.g. 35mA instead of 40mA (for a dev board).
5. How much reduction in power use will dynamic clocking be able to give in the best case scenario of running the Pro Processor at its slowest reasonable speed?
6. What is the lowest speed dynamic clocking might give which is still able to run BLE normally?
7. What are the timeframes for the required functionality that may address these issues and what reliability to they have?

Please note: We require answers to these questions in a short timeframe in order to ensure our business makes a timely decision for our future products, please ensure the responses are considered and correct.

ESP_Sprite
Posts: 4027
Joined: Thu Nov 26, 2015 4:08 am

Re: BLE power consumption

Postby ESP_Sprite » Sun Mar 04, 2018 7:29 am

If you are a business and need guaranteed support, I suggest you contact us directly (sales at espressif.com); this forum mostly is a community hub and the engineers answer on a best-effort basis only here.

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