Dual-mode capacitive transimpedance amplifier, and read-out device incorporating the same

A capacitive transimpedance amplifier for a detector unit capable of generating first and second detection currents flowing respectively in opposite directions, said capacitive transimpedance amplifier comprising:

• a read-out circuit having an input node adapted to be connected electrically to the detector unit, and an output node, and including
• an integration capacitor having a first end coupled to said input node, and a second end,
• first and second transistors adapted to be connected in series between first and second reference potentials, a first common node between said first and second transistors being coupled to said second end of said integration capacitor, each of said first and second transistors having a control end, and
• a sampling and holding unit coupled between said first common node and said output node for sampling and holding a voltage at said first common node;
• and
• a switch unit adapted to be connected between third and fourth reference potentials, and connected electrically to said control ends of said first and second transistors and said input node of said read-out circuit;
• wherein said switch unit is operable between a first state, where said control ends of said first and second transistors are coupled respectively to said input node and the fourth reference potential through said switch unit such that the first detection current from the detector unit is read out by said read-out circuit, and a second state, where said control ends of said first and second transistors are coupled respectively to the third reference potential and said input node through said switch unit such that the second detection current from the detector unit is read out by said read-out circuit.