NFC signal amplification

Thread Starter

dudeism

Joined Jul 13, 2016
13
Hey, I am making an NFC based project and want to power another circuit around 10-12 V using nfc from my phone. Is it possible? Which opamps should I use?
 

DickCappels

Joined Aug 21, 2008
10,153
Possibly but very little power would be available. Is there any reason you can't try some experiments, such as by adding a capacitor to your coil to make it resonant at 13.6 MHz and then use a detector (such a Schottky 1N60 or a Calmos CMS 8250 LF zero bias detector followed by a low pass filter and then see what kind of power you can get out of it? Increasing the number of turns should increase the voltage but remember to change the capacitor to keep the resonant frequency at 13.56 MHz.

You can take power (but not much!) from across the capacitor in the circuit below.
upload_2016-7-14_12-54-45.png
 

DickCappels

Joined Aug 21, 2008
10,153
Individual LEDs do not conduct AC, at least they don't last very long in that mode. Your LED is probably acting like the diode in the circuit.

You might be able to make an estimate of the current by comparing the intensity of the glow from the LED with that of the glow when running from a direct current source such as a battery, a pot and a fixed resistor in series.

If you make the diode detector you can measure millivolts and milliamps and calculate power.
 

DickCappels

Joined Aug 21, 2008
10,153
Not with that opamp -it runs out of gain at 10 MHz.

Your original intent was to derive power from the NFC signal from your phone. If you use and amplifier, from where would the amplifier get its power? Or, has your goal changed?

Maybe you would be interested in a RFID or wireless charging project, both of which can provide more power.
 
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