LoRa-E5-HF Sleep current demand

[Michael_Head]

I am using Seeed Studio LoRa-E5-HF.
I have not changed the internal software in this module.
I am using the circuit shown in Section 5.3 Reference design based on LoRa-E5 module, Figure 12, shown in the LoRa-E5 Datasheet V1.1
I supply Vcc = 3.3 Volts.
This datasheet in Section 1.1, Feature, shows “Low power consumption: as low as 2.1 uA sleep current (WOR mode)”.
I send the AT command “AT+LOWPOWER” as shown in Section 4.30 LOWPOWER in the LoRa-E5 AT Command Specification.
The LoRa-E5 responds to AT+LOWPOWER with “+LOWPOWER: SLEEP”
When I next send AT the LoRa-E5 responds with “+LOWPOWER: WAKEUP”
I am confident the LoRa-E5 has correctly entered LOWPOWER mode.
But I see about 2 mA current flowing from Vcc.

Question #1: How much current should flow from VCC into the LoRa-E5 in LOWPOWER mode?
Question #2: What document describes WOR mode?
Question #3: Please describe the AT commands required to get 2.1 uA sleep current.

Thanks for answers!

[msfujino]

This may not be a direct answer, but I think the following link may help you.

Node using XIAO_nRF52840 and Grove-LoRa-E5 running on AT commands, sleep current 6.4uA

Using a XIAO_nRF52840 as the host controller and a Grove LoRRa-E5 as the LoRa module, I investigated how low the sleep current could be when a node was configured using AT commands only. I hope this will be helpful to those interested. The configuration is shown in the figure below, with 3.6V supplied from a PPK2 to the battery pads on the back of the XIAO, and 3.3V supplied from the 3V3 pin of the XIAO to the VCC pin of the LoRa-E5. The LDO of the LoRa-E5 has been removed to supply the 3.3V. …

Programming LoRa-E5 with Arduino, Grove-LoRa-E5 sleep current 0.7uA

In the link below I have investigated how low the sleep current can be when configured using the XIAO_nRF52840 as the host controller and using only AT commands and posted that it is 6.4uA. ‘https://forum.seeedstudio.com/t/node-using-xiao-nrf52840-and-grove-lora-e5-running-on-at-commands-sleep-current-6-4ua /273830’ The Wiki has an example of LowPower using the STM32CubeIDE without AT commands, but the STM32CubeIDE is too complicated for me. So I investigated how to program the LoRA-E5 using t…

[Michael_Head]

Yes indeed! I have a Grove LoRa-E5 board. Testing it shows 45 uA after just AT+LOWPOWER. I didn’t remove the regulator but this 45 uA test results shows that AT+LOWPOWER command at least reduces the current demand greatly. I’m hunting a 2 mA current draw so now I know I’m sending a good command and that this current is NOT going into the LoRa-E5. I’ll hunt elsewhere.

One note… I noticed that the LoRa-E5 TxD (pin 10) in LOWPOWER mode becomes tri-stated. This is a problem for driving other logic if this logic doesn’t have pull-up or pull-down. The tri-state output will allow other logic input to float and results in substantial current demand (on the order of 1 mA) by transistors within the logic.

Thanks for the link. It helped a lot. Tomorrow I’ll pull the Grove LoRa-E5 regulator as you did and see how low I can go.

[msfujino]

Consider the AT commands in my sketch.
Good luck!!!
.