| Electronics > Projects, Designs, and Technical Stuff |
| low power 125khz receiver |
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| 2ndherbert:
Dear analog circuit designers, ^-^ I am working on my thesis, the main part of witch consists of software with "minor" hardware design. I am familiar with digital design but not much into analog stuff. So far so good. My thesis includes the design of a 125khz low power, always on receiver. What i need: Get from 100µVpp 125khz (on-off keying with 9600bps) to the rectangular envelope signal with 3.3V (down to 2.5V). What i have: A very limiting budget battery supply with 3.6V down to 2.5V at EOL and as topping i can serve about a few µA standby current (no 125khz field) What i came up with: I thought about using a J-Fet in a common source configuration to get the voltages upto maybe some mV and than using a ultra low power comparator to further amplify the signal. The than rectangular 125khz signal i can rectify and feed through a loaded lowpass to generate the envelope. What problems i have: Finding proper j-fets for these low cutoff voltages witch are working under these low bias currents, best i can find so far is the TF412S https://www.onsemi.com/pub/Collateral/ENA2300-D.PDF Fully understanding all the parasitic and sometimes added capacities around the common source amplifier. Are there some good design guides? I will build the circuit this week, but i am expecting a lot of trouble since getting the circuit stable was already difficult in the simulation. Am i on the road to hell or is there some hope? :-// |
| Howardlong:
Is this RFID? |
| ogden:
You shall specify what you mean by "low power" and "always on". I would consider Tayloe detector/mixer based receiver. http://www.norcalqrp.org/files/Tayloe_mixer_x3a.pdf |
| 2ndherbert:
--- Quote from: Howardlong on March 11, 2019, 09:15:17 pm ---Is this RFID? --- End quote --- This is not RFID. I have looked at RFID circuits but i have not found one with low power consumption. --- Quote from: ogden on March 11, 2019, 09:33:12 pm ---You shall specify what you mean by "low power" and "always on". I would consider Tayloe detector/mixer based receiver. http://www.norcalqrp.org/files/Tayloe_mixer_x3a.pdf --- End quote --- With "always on" i meant that it is no option to turn the receiver off for a certain amount of time, it has to be ready all the time. Low power means max 5µA with no 125khz signal on the receiver (i don't now when there is a field that is why i referred to "standby" and always on) |
| Howardlong:
What is the 100uV pp from? Is it a tuned loop antenna? |
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