DIFFERENTIAL PHOTODIODE INTEGRATOR CIRCUIT FOR ABSORBANCE MEASUREMENTS

摘要

Systems and methods for measuring a light intensity. An example photodetector measurement circuit comprises a photodetector that receives a light and generates a photodetector current indicative of the light intensity. The measurement circuit includes a first integrator coupled along a first signal path to the photodetector to generate a first voltage signal at a first integrator output indicative of an integral of the photodetector current level. A second integrator is configured to generate a second voltage signal at a second integrator output indicative of an integral of the photodetector current level. A differential amplifier receives the first voltage signal and the second voltage signal and generates a third output signal at a differential amplifier output indicative of a difference between the first voltage signal and the second voltage signal. The differential amplifier outputs the third voltage signal to an analog-to-digital conversion function (“ADC function”) input.

主权项

1. A photodetector measurement circuit comprising:
a photodetector configured to receive a light having a light intensity and to generate a photodetector current with a current level indicative of the light intensity, the photodetector having a first terminal and a second terminal where the photodetector current flows through the photodetector from the first terminal towards the second terminal; a first integrator coupled along a first signal path to the first terminal of the photodetector, where the first integrator is configured to generate a first voltage signal at a first integrator output indicative of an integral of the photodetector current level; a second integrator coupled along a second signal path to the second terminal of the photodetector, where the second integrator is configured to generate a second voltage signal at a second integrator output indicative of an integral of the photodetector current level; and a differential amplifier configured to receive the first voltage signal at a first differential amplifier input, to receive the second voltage signal at a second differential amplifier input, and to generate a third output signal at a differential amplifier output indicative of a difference between the first voltage signal and the second voltage signal, where the differential amplifier is further configured to output the third voltage signal along a fifth signal path to an analog-to-digital conversion function (“ADC function”) input.