Question about Avalanche Photodiode (APD)

Discussion in 'The Projects Forum' started by KOOPI, Aug 15, 2014.

  1. KOOPI

    Thread Starter New Member

    May 11, 2014
    Hi everyone,

    How can I reach the breakdown voltage without applying the voltage written in the datasheet (80 volts!) , can I build a simple amplifier circuit with a battery of 5 V?
    I wonder because every regular range meter with APD has a battery of 3 volts, so how do they reaching the brakdown voltage??
  2. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    hi Koopi,
    Please post the datasheet or a type number.

  3. DickCappels


    Aug 21, 2008
    Voltage are up-converted by either using a forward converter with a high secnondary-to-primary tunrs raio or a boost converter of some sort. The voltage on the cathode of the right-most diode in the boost conveter is about 90 volts. That should get you pretty close. You might want to look around for other boost or "flyback" circuits on the web. By the way, the output of this supply will probably need heavy filtering before applying it to a photdiode circuit.


    I made a boost converter using an NE555 because I didn't have the Linear Technology chip available. Adjust the 500 ohm pot to obtain the desired output voltage; it can probably reach 80V with the values shown.

    Last edited: Aug 15, 2014