modeling the Photodiode for Circuit use

Discussion in 'The Projects Forum' started by shantanu, Aug 5, 2008.

  1. shantanu

    Thread Starter Member

    May 26, 2008
    Hi I am doing a project related to Delta Sigma sensing. I want to model a photo diode with help of spice code. Its kind of tricky for me because I don't know how much current should flow through photo diode.

    Considering an analogy to practical situation where I have connected a photo diode to circuit and I don't know how much current it will draw, but using Delta Sigma sensing scheme i will calculate how much current it will sink.

    So I want to know how can i model it.

    thanks for the reply

  2. scubasteve_911

    AAC Fanatic!

    Dec 27, 2007
    The current flowing through is simple the sum of : dark current and current induced due to incident light. The amount of current due to applied light should be well documented in terms of applied power versus wavelength. Or, expressed as a sensitivity in Amperes/watts of light.

    There are various types of photodiodes available and each act very differently. This sensitivity curve should be specific to each device, which makes it a difficult task. Secondly, you need to know about its capacitance and inductance/resistance for a precise model.

    Good luck,