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Teensy 3.1 power supply

Anon_LG

Jun 24, 2014
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For my next project I have decided to make a companion cube (from the portal story) style thing, screams when it is to cold, to cold, whines when low on power, outputs messages through speaker and lcd display etc. I have not managed to find an article or page that specifically tells me what ranges of voltage to supply for the different power modes. I have managed to gather a few pieces of information on power supply but none of them seem clear to me, the answers may be there and I am missing them, however I have looked for a while now and can not find the answers. My 2 questions are:

1. In 3.3 volt mode, what ranges should I supply externally?

2. In 5 volt mode, what ranges should I supply externally?

Help to either or both questions is greatly appreciated.
 

Harald Kapp

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I have not managed to find an article or page that specifically tells me what ranges of voltage to supply for the different power modes

Can you elaborate on that a bit? I don't grasp it:

The power you need to supply is determined by the power consumption of your load. For the same power the current is inversely proportional to voltage since P=I*V.

The power supply to the teensy is 3.7V...5V, there is obviously an internal 3.3V regulator on-board. I can find no reference to the 3.3V mode or 5V modes you list.

In case you refer to the teensy's inputs being 5V tolerant (only V3.1, not V3.0!), this only means that while designed for 3.3V operation, the teensy 3.1 can tolerate up to 5V at the digital inputs. The datasheet for the processor states:
  • ViH > 0.7*Vdd
  • ViL < 0.35*Vdd
where Vdd is the operating voltage of the processor, very liekly 3.3V on the teensy 3.1
 

Anon_LG

Jun 24, 2014
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There are 2 pads on the underside marked "5V" and "3.3V", I thought these were for power however you have answered my question on power supply, by stating that the supply voltage is 3.7V to 5V. Thankyou Harald Kapp.

The thing was on this page: https://www.pjrc.com/teensy/external_power.html, the diagram shows supply voltages down to 2.6V, however does not state the case for teensy 3.1 only for teensy 2. This made me unsure.
 
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