HL7800 doesn't settle down

IoT Modules HL78
1

Is it normal for the HL7800 to consume power when it’s hibernating in an erratic way?

We have configured the HL7800 in the following way:
For 2-wired UART (TX/RX),
eDrx Hibernate mode, we set:
AT+CEDRXS=1,4,5 //CATM1-81.92s
AT+KSLEEP=1,2 //Standalone-Hibernate

We allow a 10 minute calibration time, or simply wait 10 minutes or more to allow it to settle down.
We find that the HL7800’s power consumption will drop down into the uA but every few seconds it will jump and reach between 10 and 20 mA every 1-10 seconds.
It never seems to just settle down for any kind of hibernation period.

The pulses make the average consumption of our low power system difficult to achieve. There’s no other powered device on this 3.7V power rail except for the active GPS antenna (which is switched off), and a low power level converter (from the 1.8V VPGIO)

2

Hi @Rique,
As you know, eDRX allows the module to not monitor every Paging Occasion (PO), but only the POs that belong to the Paging Time Window (PTW) as figure 1 below

image
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From figure 2, You can see after the internal clock calibration is complete, the module only wake up for the duration of PTW time at the end od eDRX cycle. At this moment, the consumption will increase to paging occasion (PO) then it will drop down into the uA

image
image956×463 146 KB

You can refer to AirPrime_HL7800_Low_Power_Modes_Application_Note_Rev2_0.pdf (627.3 KB) for more details. Please share any concerns you have and help tick Solution if your question is answered
Thanks

1 Like
3

Thanks. We ended up going with PSM since it suited our needs better.
Thanks