Reduce power consumption when use external GPS Antenna on Thingy91

[Nahan_Trogn]

Hi,

When attaching external GPS Antenna to Nordic Thingy91, I realize that the power consumption increases by about 5mV. Are there any ways that I can config to unuse this external antenna when GPS not working to reduce power consumption?

[JONATHAN LL]

Hi,

What thingy version are you using?

Have you disabled the LNA 
https://infocenter.nordicsemi.com/topic/ug_thingy91/UG/thingy91/hw_description/gps_thingy91_140hw.html?cp=14_0_6_2_3_1 


The J2 connector does not have its own DC-feed, it is powered by 3.3V, so it cant be easily controlled individually. 

For Thingy91 v1.5 or earlier :with a active antenna then the LNA will be powered al the time. It is possible to turn of the 3.3V power domain on the PMIC trough I2C, but then all the RF frontend component will be powered down. So the you have to make sure that there is no activity by the modem, that is more or less only during longer sleeping periods that that would be practical/possible.  

There will be some changes on the newer HW version that addresses this issue.

Regards,
Jonathan

[Nahan_Trogn]

Hi, I used Thingy91 v1.4.0. 

Thanks for your response. I'll try it and inform you the result.

You mean that the LNA used for external antenna consumes more power than internal antenna?

By the way, if I disable LNA, the GPS signal will be weaker. ShouId I manually turn on/off it at runtime?

[JONATHAN LL]

Hi,


I mean the LNA on the Thingy91 should be disabled. 

 

Nahan_Trogn said:

You mean that the LNA used for external antenna consumes more power than internal antenna?

 This might be the case, but the only way to disable the external antenna is to turn of the 3.3V supply. 

Regards,
Jonathan