Optoelectronic receiver circuit with dark current correction function and dark current correction method thereof

A dark current correction method, comprising following steps:

• (1) providing an optoelectronic receiver circuit comprising:
• a transimpedance amplifier;
• a first variable resistor electrically connected between a positive input end and a negative output end of the transimpedance amplifier;
• a second variable resistor electrically connected between a negative input end and a positive output end of the transimpedance amplifier;
• a photodiode electrically connected to the positive input end of the transimpedance amplifier;
• a leakage compensation photodiode electrically connected to the negative input end of the transimpedance amplifier;
• a plurality of first leakage correction photodiodes, being electrically connected to the positive input end of the transimpedance amplifier, and also electrically connected in parallel with the photodiode;
• a plurality of first switches, wherein any one of the first switches is connected between a corresponding one of the first leakage correction photodiodes and the positive input end of the transimpedance amplifier;
• a plurality of second leakage correction photodiodes electrically, being connected to the negative input end of the transimpedance amplifier, and also electrically connected in parallel with the leakage compensation photodiode;
• wherein all the leakage compensation photodiode, the first leakage correction photodiodes and the second leakage correction photodiodes is provided with a light isolation cover thereon, such that the leakage compensation photodiode, the first leakage correction photodiodes and the second leakage correction photodiodes are unable to receive any light;
• and
• a plurality of second switches, wherein any one of the second switches is connected between a corresponding one of the second leakage correction photodiodes and the negative input end of the transimpedance amplifier;
• (2) determining whether a positive output signal and a negative signal outputted by the transimpedance amplifier constitute a fully-differential driving signal or not;
• if yes, proceeding to step (4);
• otherwise, proceeding to step (3);
• (3) using a micro controller to adjust the resistance of the first variable resistor and the second variable resistor, so as to make the positive output signal and the negative output signal constitute the fully-differential driving signal;
• (4) letting the transimpedance amplifier output the fully-differential driving signal to an analog-to-digital converter, so as to make the analog-to-digital converter output a digital signal with a dark current digital portion to the micro controller;
• (5) determining whether the dark current digital portion is adjusted to minimum or not by the micro controller;
• if yes, proceeding to step (7);
• otherwise, proceeding to step (6);
• (6) by using the micro controller, at least one first switch being switched to short circuit for making at least one first leakage correction photodiode be electrically connected in parallel with the photodiode;
• moreover, at least one second switch also being switched to short circuit for making at least one second leakage correction photodiode be electrically connected in parallel with the leakage compensation photodiode;
• then, repeating the step (5);
• and
• (7) ending the steps.