Hello,
Recently we changed our hardware design. The BC66 was replaced by the BG77.
The BG77 is operated in NB-IoT mode and we expected to see the same power consumption. What we observe is, that the BG77 uses twice as much energy as the BC66 did.
Sending a 64 byte UDP package with the BG77 draws much more current then the BC66 did. Integrated over time we see:
Energy consumption of a 64 byte UDP package:
BC66: 0.9 Joule
BG77: 2.2 Joule
This is really bad news for us. What could be the reason for the increased power consumption? The antenna and everthing else is the same. One more finding is, if I disconnect the antenna it needs also 2.2 Joule. Does the BG77 transmitt always with the maximum power regardless of the performance of the connected antenna or could it be a hardware design issue?
So the question is, is the doubled energy consumption expected or is there something wrong?
Thanks in advance,
Andreas
How to interpret the screenshots of scope:
Measured was the current consumption over a current sensor board where 1mA = 10mV. Therefore a dY of 2.46Wb corresponds to 0.246As multiplied by 3.7V = 0.9Ws = 0.9J
By comparing the power consumption of BC66 and BG77 in the data transmission state, BG77 power consumption is larger, which is mainly determined by the chip; If you only need NB, it is recommended to choose BC660K
Thank you for the quick reponse. Can you please point out more detailed why the consumption is larger? From your post I guess the transmitt power of the BG77 is not higher than the one of the BC66. So where does the energy go to?
The BG77 kernel has more tasks to handle, and BG77 supports more network standards, but BC66 only supports NB
If it would be used by additional tasks there would be an increased base consumption, but it doesn’t look like that to me.
Instead the whole pattern is scaled up including the peaks. Please give me a more plausible explanation.
My personal understanding is this, you can try to execute AT+CFUN=0,AT+QSCLK=1, turn off the modem function, only enable AP core work
I assume the current consumption of the AP core (with modem turned of) is a well documented value.
Can you please look the values up for the BC66 and the BG77 so that we know what to expect?
I did not find the sleep power consumption of BC66 under cfun0, but BG77 has been given in the hardware manual
Any news on this? Would it be possible to reachout for someone in your company who could answer the question?
The problem is chips and internal programs, and I think I’m right
Thank you for your response. Unfortunately, it does not satisfactorily address the issue of the BG77’s double energy consumption compared to the BC66. Simply stating that the chips and internal programs are responsible does not explain the specific cause of the increased power usage. Could you please provide more detailed information on which specific features or functions of the BG77 lead to this higher consumption?
Thank you for your efforts!
We do not have any documentation on this issue
