CC2340R5: Not achieving low power.

Hello Krishna, 

We will look into this and get back to you as soon as possible. In the meantime, can you clarify if you are using a custom board? 

Thanks, 

Isaac

Hi,

Can you clarify what you mean by standby current? Is this the average current draw seen between RF events, when the device is in standby? In other words, is the number you are providing the overall average or simply the average between peaks in the image below:

Did you disable the display module? This can be done through the advanced setting tab within the BLE Module in sysconfig. Did you remove the jumpers on the LEDs on the LaunchPad? This can increase current draw.  I have previously taken a capture of a modified empty project running on a LaunchPad and observed the following standby measurements:

Which shows a 2-3 second measurement leads to an average power draw of 707nA which is in-line with what is mentioned in the data sheet. The only modifications made to the empty project was to remove the GPIO toggling and increase the standby time to 10 seconds. Can you share the measurement methodology you are using? A picture of the setup may also be helpful.

Best Regards,

Jan

Hi Jan

Thanks for the reply 

I meant the average current drawn after a particular time that is within 20-30 seconds of power on. 

This reading is taken with a Voltage of 3V, and I am getting an average of 42+ uA even after keeping an adv interval of 10 seconds.

You may check with the measurement setup. In this, I'm using an SMPS to supply power to the device.

"Did you disable the display module? This can be done through the advanced setting tab within the BLE Module in sysconfig. Did you remove the jumpers on the LEDs on the LaunchPad? "

Yes, I am disabling the display module, buttons, LEDs.  

Hi,

Understood. To confirm, you are simply measuring the average current across 10 seconds? It seems you are using basic ble.  Is basic ble operating in peripheral mode (default)? Are you connected to the device or is the device simply advertising? Seems to be advertising only but want to confirm to run the power measurement test on my end. 

Best Regards,

Jan

Yes, I have loaded the Basic_ble code operating in peripheral mode. Only advertisement it is doing while measuring the device.

Hi,

I did my own test on my side. I set up ble_basic to advertising with a 1s advertising interval and disabled the display module and got around 29.3uA average across ~3s.

I used the following project: 3618.basic_ble_LP_EM_CC2340R5_freertos_ticlang.zip

Can you try using that project on your end to confirm?

Best Regards,

Jan

Hi Jan, 

I tried the same project on my end, the current Im getting is very high which is greater than 250uA. 

May I know the following details since you have tested it yourself?

1) Are you using an LP-EM-CC2340R5 launchpad for testing?

2) Am I performing the correct procedure to measure the current? Please provide details if the procedure is not right.

Hi,

I am using a LaunchPad for my testing with the LED jumpers removed. At a glance, it looks like your launchpad is set up correctly as well. The procedure looks okay. Is the yellow wire going to VCC in your power supply? Can you change your VCC to 3.3V to ensure we have the same voltage input.

These numbers are very unexpected. It seems your minimum value is ~250uA which is much higher than expected. Can you try using gpiostandby to measure the average standby only power draw? Increase the standbyDuration value to atleast 10 seconds to ensure we are in standby for the entire duration of the measurement. Also comment out the GPIO_toggle() and the GPIO function calls to remove the LED toggling functionality. You should see a standby current of <710nA. If you do not see this, then there may be some settings or something we should change in the measurement equipment.

Can you confirm if your LaunchPad is a PG1.0 device or a PG2.0 device?

Best Regards,

Jan

Hi Jan 

Thanks for advising rightly on the process.

I have tried with our custom board, I am able to achieve a standby current of <710nA with gpiostandby code. 

"I used the following project: 3618.basic_ble_LP_EM_CC2340R5_freertos_ticlang.zip " With this code loaded to the custom board, I am achieving a current close to 29.3uA. 

where this current is expected to be comparatively low. Considering the standby current of take, 1uA, for a 1-sec interval and take 9mA of Radio transmit for 300 us, the average current should be an even reduced current to 3-4uA, correct me if I am wrong. Our application required a low-power functionality in order to work on the battery. Guide me to achieve an even lower current so that it could satisfy the application feature. 

Hi,

I am glad to hear on the custom board we are seeing the expected power draw. There's a few things we can do to maximize our power savings.

1. We can try to minimize how much data we transmit (reducing radio on time).

2. We can extend the connection interval and advertising interval to transmit less frequently.

3. We can ensure all of the GPIOs are in the optimal pull configuration.

4. We can reduce the txPower (this will have an impact on range) to reduce the current draw during the transmit.

5. Submit your design for a Design review to verify if there is anything major that could be causing additional power draw.

Can you try the five suggestions above to see if we can further reduce the power draw?

Best Regards,

Jan