The sleep state power consumption of LoRa nodes (also called sleep state power consumption, or standby power consumption) should be extremely low, such as the LoRa temperature and humidity sensor composed of RAK4200+SHTC3, which uses ST's low power Consumption of MCU, can make the LoRa node not collect and transmit data, the standby current can be reduced to 4uA!
When the power consumption of the LoRa node in the sleep state is abnormally high, it may be that the LoRa node has some failures, or we need to modify some settings.
We can first check whether the code MCU enters the sleep mode, such as the stm32 series, in order to maintain the RAM content, it needs to enter the stop mode.
Next, consider checking the MCU peripheral code. Before the MCU enters the sleep mode, all peripherals, such as serial ports, ADCs, timers, etc., should be turned off. It is necessary to check whether these peripherals have been turned off when entering sleep mode.
You can also consider checking the chip code of the LoRa node to see if the LoRa chip enters sleep mode.
Another point that is most easily overlooked is the need to check whether the signal pin of the RF switch chip is disabled. If you forget to turn off the RF switch, there will usually be a leakage of hundreds of microamperes. Compared with the normal standby power consumption of several uA, this kind of leakage of the order of hundreds of microamperes is absolutely unacceptable. If the LoRa chip uses an active crystal oscillator, the power supply pin of the active crystal oscillator needs to be pulled down.
How to reduce the power consumption of LoRa nodes, you can also refer to the article LoRa terminal low power consumption strategy .