Controlled feedback charge-to-voltage converter
AssigneeThomson-CSF Semiconducteurs Specifiques
InventorJean-Alain Cortiula
Life of this patent
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Abstract
The invention concerns a charge-to-voltage converter including a read diode and a read transistor of no-load gain G.sub.o. The converter includes complementary circuits assuring a conversion gain greater than G.sub.o during read periods and a conversion gain substantially equal zero at other times.
Claims12
A charge-to-voltage converter including a read diode, across which a first voltage appears, and a read transistor whose no-load gain is G.sub.o and whose gate is connected to said read diode, such that said first voltage is applied to said gate, and whose source is the point at which the output voltage of said converter is produced, and wherein said charge-to-voltage conversion is carried out in three time intervals, a first interval during which the capacitance of the diode is pre-charged, a second interval during which the diode is floating, and a third interval during which the signal resulting from the charge to voltage conversion is read, said converter also including means of controlling the gain G of said output voltage over said first voltage, such that gain G is substantially equal to zero during the first interval and greater than gain G.sub.o during the second and third intervals, wherein said means of controlling the gain G are an amplifier providing a gain K and a transistor connected as a inverter providing a no-load gain equal to -G.sub.1, this amplifier having its input connected to a point at which the output voltage is collected and its output connected to the gate of said transistor connected as an inverter, this transistor having its drain connected to the input of the amplifier and its source connected to the ground of the device, such that the gain G of the device is given by:
- G=G.sub.o /(1+K.G.sub.1)
A charge to voltage converter including a read diode, across which a first voltage appears, and a read transistor the no-load gain of which is G.sub.o, said transistor having a gate connected to said read diode, such that said first voltage is applied to said gate and a source connected to a load transistor and to an output node, and wherein said charge to voltage conversion is carried out in three time intervals, a first interval during which the diode is precharged, a second interval during which the diode is floating, and a third interval during which a read voltage resulting from a charge-to-voltage conversion is produced at said output node, said converter further comprising a feedback loop between said output node and a gate of said load transistor for controlling the gain G of said output node voltage over said first voltage.
Dependencies are inferred from the claim text.