×

Photoconductive photodiode built-in test (BIT)

  • US 8,290,726 B2
  • Filed: 04/28/2010
  • Issued: 10/16/2012
  • Est. Priority Date: 04/28/2010
  • Status: Active Grant
First Claim
Patent Images

1. A detector, comprising:

  • a photodiode reverse-biased to operate in a photoconductive mode in which incident photons on the photodiode produce a photocurrent signal at the photodiode'"'"'s cathode;

    a transimpedance stage that converts the photocurrent signal to a voltage signal;

    a processor that processes the voltage signal to characterize the photons incident on the photodiode; and

    a built-in test (BIT) circuit comprising;

    a circuit element coupled to the photodiode'"'"'s anode;

    a solid-state switch coupled to the circuit element, said switch responsive to a control signal to produce a time-varying voltage signal that is coupled through the circuit element to the anode of the photodiode and through a parasitic capacitor between the photodiode'"'"'s anode and cathode to produce a test current signal at the photodiode'"'"'s cathode,said processor processing the voltage signal produced by the test current signal to provide a measure of the health or characteristics of the parasitic capacitor as a proxy for the health or characteristics of the photodiode.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×