US 10,199,990 B2Granted

High dynamic range device for integrating an electrical current

AssigneeUlis

InventorPatrick Robert

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Abstract

A device for integrating an electric current during a period Tint, including an operational amplifier and a capacitor connected between a first input and an output of the amplifier, a second input of the amplifier being taken to a voltage VBUS, output voltage Vout of the amplifier being saturated at a high voltage VsatH and a low voltage VsatH according to the charge quantity in the capacitor. The device also includes: a circuit for switching the terminals of the capacitor; and a circuit for triggering the circuit at least once during period Tint when voltage Vout both grows and is substantially equal to a reference voltage VREF, the voltage VREF being smaller than or equal to voltage VsatH, and reference voltage VREF and voltage VBUS being selected to comply with relation 2·VBUS−VREF≥VsatL; and a storage circuit for storing the number of triggerings having occurred between the initial time and the end time of the integration period.

Claims10

Dependent claims

A device for integrating an electric current received on an integration node for a period of predetermined duration Tint, comprising an operational amplifier having a first and a second input and an output, and a capacitor having two terminals connected between the first input and the output of the operational amplifier, the second input of the amplifier being taken to a constant voltage VBUS, the first input of the amplifier being connected to the integration node, and the output terminal of the operational amplifier supplying an output voltage Vout which varies monotonously in a predetermined variation direction according to a quantity of electric charges of predetermined polarity stored in the capacitor, output voltage Vout of the operational amplifier being saturated at a high saturation voltage VsatH when the quantity of electric charges of said polarity stored in the capacitor is greater than a predetermined threshold, and output voltage Vout of the operational amplifier being saturated at a low saturation voltage VsatL when the quantity of electric charges of said polarity stored in the capacitor is smaller than a predetermined threshold,

wherein the device further comprises:
a circuit for switching the capacitor terminals between
a first position in which a first terminal of said capacitor is connected to said first input of said operational amplifier and a second terminal of said capacitor is connected to said output of said operational amplifier;
and
a second position in which said first terminal of said capacitor is connected to said output of said operational amplifier and said second terminal of said capacitor is connected to said first input of said operational amplifier;
a circuit for triggering the switching circuit at least once during integration period Tint when output voltage Vout of the operational amplifier both varies in said variation direction and is substantially equal to a reference voltage VREF;
and
a storage circuit for storing the number of triggerings having occurred between the initial time and the end time of the integration period,
and wherein:
when said variation direction is increasing, said reference voltage VREF is smaller than or equal to high saturation voltage VsatH, and reference voltage VREF and voltage VBUS of the second input of the operational amplifier are selected to comply with relation
2·VBUS−VREF≥VsatL;
or
when said variation direction is decreasing, said reference voltage VREF is greater than or equal to low saturation voltage VsatL, and reference voltage VREF and voltage VBUS of the second input of the operational amplifier are selected to comply with relation
2·VBUS−VREF≤VsatH.

11 more elements

A method of integrating an electric current during a predetermined integration duration Tint in a capacitor having two terminals connected between a first input and the output of an operational amplifier, the operational amplifier comprising a second input taken to a constant voltage VBUS, output voltage Vout of the operational amplifier varying monotonously in a predetermined variation direction according to a quantity of electric charges of predetermined polarity stored in the capacitor, said output voltage Vout being saturated at a high saturation voltage VsatH when the quantity of electric charges stored in the capacitor is greater than a predetermined threshold, and output voltage Vout of the operational amplifier being saturated at a low saturation voltage VsatL when the quantity of electric charges of said polarity stored in the capacitor is smaller than a predetermined threshold, the method comprising the steps of:

a) before the initial time of integration period Tint, initializing to zero the capacitor charge and a counting value;
b) integrating during integration period Tint the electric current in the capacitor;
c) switching the capacitor terminals at least once during integration period Tint when the output voltage of the operational amplifier both varies in said variation direction and is equal to a predetermined reference voltage VREF, said switching occurring between a first position, in which a first terminal of said capacitor is connected to said first input of said operational amplifier and a second terminal of said capacitor is connected to said output of said operational amplifier, and a second position, in which said first terminal of said capacitor is connected to said output of said operational amplifier and said second terminal of said capacitor is connected to said first input of said operational amplifier,
when said variation direction is increasing, said reference voltage VREF being smaller than or equal to high saturation voltage VSatH, and reference voltage VREF and voltage VBUS of the second input of the operational amplifier are selected to comply with relation
2·VBUS−VREF≥VsatL;
or
when said variation direction is decreasing, said reference voltage VREF is greater than or equal to low saturation voltage VsatL, and reference voltage VREF and voltage VBUS of the second input of the operational amplifier are selected to comply with relation
2·VBUS−VREF≤VsatH;
d) incrementing by one the counting value after each switching of the capacitor during integration period Tint;
and
e) after the end time of integration period Tint, supplying the counting value.

8 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/300,641Filed 30 Apr 2015
Priority: FR 14 541197 May 2014
Published: US 2017/0111015 A120 Apr 2017
Granted: 5 Feb 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

H03F 1/26
Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements: modifications of…
G01J 5/24
Electrical features thereof: use of specially adapted circuits, e.g. bridge circuits
H03F 3/005
Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements: using switched capacitors, e.g. dynamic amplifiers;…
H03F 3/087
Controlled by light: with IC amplifier blocks