Patent ID: 6479810
Filing Date: 2002-11-12
Classification: G01J

Abstract:
A light sensor assembly comprising:a photodiode which detects a certain amount of light and, in response to said detected certain amount of light, generates an electrical current signal; a first amplifier which is coupled to said photodiode; a logarithmic amplifier circuit which is coupled to said photodiode and to said first amplifier; a second amplifier which is coupled to said logarithmic amplifier circuit; and a power supply which only provides a voltage signal having an amplitude which is greater than zero and wherein said second amplifier causes an offset current signal to flow through said logarithmic amplifier, effective to cause said photodiode to only operate in a photoamperic mode and wherein said logarithmic amplifier produces a voltage output signal which is communicated to said second amplifier, said second amplifier further receiving an offset voltage signal which cooperates with said received voltage output signal to cause said second amplifier to produce an output signal which is representative of said detected certain amount of light, said output signal being constrained to vary only between zero and five volts.