I am not expert in electronics so there must be many errors that I am not considering. I designed a simple half wave rectifier that gives signal to a LDO voltage regulator of 3V3. In the input I have a sine wave that should have a frequency of 13.56 MHz and an amplitude of 10 V. However, when I choose a 500Hz wave the LED at the output of the LDO is working but at 1KHz, the LED is off. the voltage drops to a few mV.
I am using the following schematic that is extremely simple (the purpose is to design a bioimplantable device for the brain, so that's why it must be simple)
simulate this circuit – Schematic created using CircuitLab
The datasheets of the LDO that I used is:
https://www.sparkfun.com/datasheets/Components/LD1117V33.pdf
Just for leting you know, I am basing my circuit in the design of John Rogers :
https://www.nature.com/articles/s41928-018-0175-0?WT.feed_name=subjects_engineering
What is the problem and how could I solve it. I attach some pictures.
Best Answer
If you want a half wave rectifier, put the capacitor between diode and regulator, not before the diode. Now the incoming AC can discharge the capacitor. Also at high frequencies the average voltage over would be zero, at lower frequencies the capacitor voltage will follow the input voltage.