| Electronics > Beginners |
| Not expected rising current in Sleep mode |
| (1/1) |
| adhoc_user:
Hi folks, we are testing our stm32L4 with a LoRaModule (SX1278 named as RA-02). We always (tested with 2 boards) have a unexpected rising curve of the current after a TX-transmission or touch event. If we push the RA-02 module to a side with little force or touches some pads of the module the current is falling to the real sleeping current(µC is sleeping). But a few seconds later the current is rising again :scared:. And the module is well soldered, we have checked every solder joint. If we disconnect the vdd jumper brigde (only for this module) the current has a permanent low value. So the circuit after this vdd bridge to lora should be the problem. What caused the rising current? Bad PCB? Bad Connections? Thanks in advance for hints! |
| adhoc_user:
OK, solved by myself. The lora-module has in sleep mode an active SPI_CS pin, you can wake up the module with spi. By default our µC-pins are in analog mode with high impedance in sleep mode. This pin on sx1278 needs a permanent pull-up in sleeping time. Otherwise its floating and does "something" which cause the extra current. Now we have ~60µA :popcorn: |
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