Hi Luis,
When i connect the NMEA4WIFI with a USB port to the PC, should i disconnect the 12V power supply ?
12V power supply
Re: 12V power supply
Hello,
Very pertinent question! You may remove the 12V power supply and everything works as far as the USB connector is capable of supplying about 250mA which they should be capable of. I say 250mA but I never made such measurement. When the multiplexer is supplied via 12V its consumption is about 90mA. The switching regulator "transforms" the 12V into 5V with an efficiency of about 94%. So when it is sinking 90mA at its input it will be sourcing about 250mA at its output.
With regard to the 2 power supplies connected in "parallel" (danger!!!) we note that the ESP32 module whose circuit diagram can be seen here, has one 1N5819 diode between the 5V_USB and the 5V. When both supplies are connected it is the 5V from the regulator that feeds the multiplexer. We also note that when we use only the USB power supply all the components of the multiplexer work with 4.4V (0.6V drop on the diode) which is sufficient.
Regards Luis
Very pertinent question! You may remove the 12V power supply and everything works as far as the USB connector is capable of supplying about 250mA which they should be capable of. I say 250mA but I never made such measurement. When the multiplexer is supplied via 12V its consumption is about 90mA. The switching regulator "transforms" the 12V into 5V with an efficiency of about 94%. So when it is sinking 90mA at its input it will be sourcing about 250mA at its output.
With regard to the 2 power supplies connected in "parallel" (danger!!!) we note that the ESP32 module whose circuit diagram can be seen here, has one 1N5819 diode between the 5V_USB and the 5V. When both supplies are connected it is the 5V from the regulator that feeds the multiplexer. We also note that when we use only the USB power supply all the components of the multiplexer work with 4.4V (0.6V drop on the diode) which is sufficient.
Regards Luis
Re: 12V power supply
Thank you Luis for these explanations.
But I did not ask my question very well.
In fact, I would like to know if there is a risk to connect at the same time USB and 12V ? ...
But I did not ask my question very well.
In fact, I would like to know if there is a risk to connect at the same time USB and 12V ? ...
Re: 12V power supply
Hello,
In few words - there is no risk!
Regards Luis
In few words - there is no risk!
Regards Luis