Power assessment of HL7800


#1

Hi,
Here I am assessing the power consumption of HL7800.
The usage is that, I need to send 100 Bytes to backend server per day. I just need a rough power consumption assessment.
I see the spec AirPrime_HL7800_and_HL7800_M_Product_Technical_Specification_Rev3_1 PAGE 25 with max current is 700mA@3.7V, but how to assess the working period according my usage?
Thanks in advance.


#2

@yinghuang,

What you are asking is, how long is a piece of string, it is heavily depended on multiple external factors (network, IP round trip time (which will vary), your hardware design, etc), all you can do is test on a devkit on the network you are using to get an idea and then design your board, after that you have to test the

There are some generic case studies and tests that have been done by 3GPP but they are not specifically applicable to the HL78 just modules in general.

Regards

Matt


#3

Hi, mlw,

Can I just make an assessment very roughly like this?

The power supply is 3.7V and average current is 215mA(Page 27 of AirPrime_HL7800_and_HL7800_M_Product_Technical_Specification_Rev3_1). I assume the handshake time as well as the data I need to send, is 10s, which is enough.

So, 3.7V215mA10s/60/60=2.2mWh

This is the power consumption for one time report, with 100 Bytes data.

For the rest time, I just make it sleep, or even cut off its power by a FET, and it can be ignored.

Thanks.


#4

@yinghuang,

Assuming you are using PSM (Power Save Mode), yes this would be a reasonable assumption. Note the current firmware (which is still in beta stage) has a 10 seconds delay built into it to enable us to interrupt the power up sequence if we generate build which screws things up, this would be removed on a final release.

Using a current build, on a test setup (so ideal conditions) we have measured under 20 seconds (including this 10 second delay) to do exactly what you have said.

Regards

Matt