- #1
QuantumLollipop
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Hi All!
A little background info. I'm working with cardiac pacemaking devices with the overall scope of implementing piezoelectric energy harvesters into the devices. I'm in the initial stages of research and development.
Okay, so this is my conundrum: I have an output pulse circuit as shown on page 13 of the attached journal (Fig 11.7). Essentially, the circuit acts as a voltage doubler by supplying controlled pulses of -2Vdd to the output (heart). The circuit requires a "pulse of sufficient magnitude to place the transistor [Q1] in the conductive state" thus turning the gears of the circuit's functionality (from steady state to conductive).
Here in lies my problem. In my prototype I have used a 13.0 MHz 20 pF crystal (digikey# 887-2036-ND) as the microprocessor/pulse source and, upon initial testing, received garbage results. I was informed that I would probably need to connect a wave (square) generator to the crystal for proper functionality. I have tried testing the circuit with just the crystal, just the wave generator, and with the generator supplying waves to the crystal. Any thoughts/advice, I'm pretty stumped.
Also, I'm certain the circuit is put together correctly as I sought help from an EE PhD student and similarly found the correct voltage drops across each capacitor during the steady state. Thanks!
https://galileo.seas.harvard.edu/images/material/3794/1321/CardiacPacemakerdesign.pdf
QL
A little background info. I'm working with cardiac pacemaking devices with the overall scope of implementing piezoelectric energy harvesters into the devices. I'm in the initial stages of research and development.
Okay, so this is my conundrum: I have an output pulse circuit as shown on page 13 of the attached journal (Fig 11.7). Essentially, the circuit acts as a voltage doubler by supplying controlled pulses of -2Vdd to the output (heart). The circuit requires a "pulse of sufficient magnitude to place the transistor [Q1] in the conductive state" thus turning the gears of the circuit's functionality (from steady state to conductive).
Here in lies my problem. In my prototype I have used a 13.0 MHz 20 pF crystal (digikey# 887-2036-ND) as the microprocessor/pulse source and, upon initial testing, received garbage results. I was informed that I would probably need to connect a wave (square) generator to the crystal for proper functionality. I have tried testing the circuit with just the crystal, just the wave generator, and with the generator supplying waves to the crystal. Any thoughts/advice, I'm pretty stumped.
Also, I'm certain the circuit is put together correctly as I sought help from an EE PhD student and similarly found the correct voltage drops across each capacitor during the steady state. Thanks!
https://galileo.seas.harvard.edu/images/material/3794/1321/CardiacPacemakerdesign.pdf
QL
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