Detection device having a photodetector connected to a terminal of an amplifier so as to reverse bias the photodetector
The detection device comprises a photodetector configured to transform an electromagnetic signal into a representative electric signal. The detection device also comprises an amplifier having a first input terminal connected to a first terminal of the photodetector. An integration capacitor is connected to the output terminal of the amplifier and to the first input terminal of the amplifier. A first source of a reference voltage is connected to a second input terminal of the amplifier. A second source of a detector voltage is connected to a second input terminal of the photodetector. The first and second voltage sources are correlated so as to correlate the noise components.
1. A detection device, comprising:
a photodetector configured to transform an electromagnetic signal into a representative electric signal;
an amplifier having a first input terminal connected to a first terminal of the photodetector;
an integration capacitor connected to an output terminal of the amplifier and to the first input terminal of the amplifier;
a first voltage source configured to deliver a reference voltage to a second input terminal of the amplifier; and
a second voltage source configured to deliver a detector voltage to a second terminal of the photodetector, the second voltage source being correlated with the first voltage source so as to correlate noise components,
wherein the first voltage source is different from the second voltage source so as to reverse bias the photodetector.
2. The detection device according to claim 1 , wherein the amplifier is unbalanced so that a voltage on the first input terminal of the amplifier is offset from a voltage on the second input terminal of the amplifier by a voltage difference at least equal to 20 mV.
3. The detection device according to claim 2 , wherein the voltage difference is between 50 and 100 mV.
4. The detection device according to claim 1 , wherein the amplifier comprises a current mirror provided with first and second shunt-connected branches, and the first branch presents different electric performances from the second branch.
5. The detection device according to claim 4 , wherein the first branch of the current mirror comprises several additional transistors connected in parallel with a main transistor, and the additional transistors and the main transistor have a control electrode connected to a same signal source.
6. The detection device according to claim 5 , wherein the first branch of the current mirror comprises several connecting switches, and each connecting switch is associated with one of the several additional transistors to enable or to disable flow of a current from each associated additional transistor.
7. The detection device according to claim 1 , wherein the first and second input terminals are respectively connected to control electrodes of first and second transistors, and the first and second transistors present different electric performances.
8. The detection device according to claim 1 , wherein the first and second input terminals are respectively connected to control electrodes of first and second transistors, several additional transistors are connected in parallel to the first transistor, and the additional transistors receive a same signal as the first transistor on their control electrodes.
9. The detection device according to claim 8 , further comprising:
several connecting switches, each connecting switch associated with one of the several additional transistors to enable or to disable flow of a current from each associated additional transistor.
10. The detection device according to claim 1 , wherein the first voltage source and the second voltage source are formed by means of an initial voltage source supplying a voltage divider delivering the reference voltage and the detector voltage different from the reference voltage.