Programmable transimpedance amplifier

Abstract

The present invention relates to a conversion device, or commonly called a transimpedance amplifier, capable of converting an input electrical current (Id) from a current source such as a photonic sensor (D) into an output electrical voltage (Vo). The device comprises an integrated electronic circuit including, among other things, a resistive component (Rf) with an adjustable value and a capacitive component (Cf) with an adjustable value. The invention also relates to a method for determining the values ​​of the resistive component and the capacitive component. Figure for the abstract: Fig. 1

Description

Title of the invention: Programmable transimpedance amplifier Technical field of the invention

[0001] The present invention relates to a conversion device capable of converting an input electrical current from a photonic sensor into an output electrical voltage and comprising an integrated electronic circuit including, among other things, a resistive component with an adjustable value and a capacitive component with an adjustable value. The invention also relates to a method for determining the values ​​of the resistive component and the capacitive component. State of the art

[0002] It is known to implement a conversion device capable of converting an input electrical current from a current source, such as a photonic sensor, into an output electrical voltage and comprising an amplification component such as an operational amplifier, a resistive component, and a capacitive component. This conversion device is commonly called a transimpedance amplifier. The amplification component, the resistive component, and the capacitive component can be implemented on the same semiconductor material substrate and thus constitute an integrated electronic circuit. The conversion device comprising this integrated electronic circuit can then be called an integrated transimpedance amplifier.

[0003] These provisions are satisfactory in that it becomes possible to achieve, using a small conversion device, a conversion of the current signal from the photonic sensor or photodetector and often of low amplitude, into a voltage signal that can be used.

[0004] However, values ​​of certain photodetector parameters may vary due to external factors such as external temperature or due to internal factors such as aging of the photodetector, for example, consequently leading to erroneous operation of the conversion device.

[0005] The present invention aims to resolve all or part of the disadvantages mentioned above.

[0006] The technical problem underlying the invention consists in particular of providing a small-sized conversion device capable of converting an input electrical current from a photonic sensor into an output electrical voltage which can compensate for variations in the values ​​of certain parameters of the photodetector and which is of simple and economical structure. Object of the invention

[0007] To this end, the present invention relates to an electronic circuit of the aforementioned type, comprising:

[0008] - an amplification component comprising at least one input port and one output port, the amplification component being characterized by a bias current value, the bias current value being modifiable in situ without removing the amplification component from the integrated electronic circuit; - a resistive component having a first terminal electrically connected to the input port of the amplification component and a second terminal electrically connected to the output port of the amplification component, the resistive component having a resistance value considered between its first terminal and its second terminal and conferring an ability to modify said resistance value in situ without removing the resistive component from the integrated electronic circuit; - a capacitive component having a first terminal electrically connected to the input port of the amplification component and a second terminal electrically connected to the output port of the amplification component, the resistive component and the capacitive component being electrically arranged in a parallel arrangement with respect to each other, the capacitive component having a capacitance value between its first terminal and its second terminal and conferring an ability to modify said capacitance value in situ without removing the capacitive component from the integrated electronic circuit; - a digital adjustment control capable of determining the following three values: the modifiable resistance value of the resistive component, the modifiable capacitance value of the capacitive component and the modifiable bias current value of the amplification component.

[0009] The amplification component may in particular refer to an operational amplifier.

[0010] The operational amplifier may have a simple input, in other words have a single input port or a differential input, in other words have two input ports.

[0011] Advantageously, the resistive component allows adjustment of a gain of the amplification component, in particular of the operational amplifier.

[0012] Advantageously, the resistive component and the capacitive component, thanks to their respective abilities to adjust the resistance value and the capacitance value, make it possible to avoid using an external adjustment component to the integrated electronic circuit described here.

[0013] Advantageously, the ability to modify the bias current value allows adjustment of the noise of the amplification component.

[0014] Advantageously, the ability to modify the bias current value allows for adjustment of the power consumption of the amplification component.

[0015] The integrated electronic circuit may also have one or more of the following characteristics, taken alone or in combination.

[0016] According to one possibility, the digital adjustment control comprises:

[0017] - a component for detecting a limit value of an output signal at the level of the output port of the amplifier component;

[0018] - a calculation unit connected to the detection component and arranged to adjust the value resistance of the resistive component and the capacitance value of the capacitive component so as to set a value of a characteristic relative to the amplification component when the limit value of the output signal is detected by the detection component.

[0019] The detection component can, for example, be a circuit for detecting a peak-to-peak voltage value.

[0020] The calculation unit can, for example, be a microcontroller connected to the detection circuit and configured to adjust the resistance value of the resistive component and / or the capacitance value of the capacitive component.

[0021] The characteristic relating to the amplification component may, for example, be the gain of the amplification component, in particular of the operational amplifier.

[0022] The output signal can be an electrical voltage, for example, which will be injected into a circuit for converting an analog signal to a digital signal, also called an analog-to-digital converter.

[0023] The limit value of the output signal may designate a peak-to-peak value of the output voltage having a predefined value, for example 1.1V, the limit value being defined so as to avoid saturation of the analog signal in the analog-to-digital converter.

[0024] According to one possibility, the resistive component comprises a plurality of resistive circuit branches, each resistive circuit branch comprising a partial resistive component, a resistive branch switch, and a control circuit driving the resistive branch switch.

[0025] The capacitive component may comprise a plurality of capacitive circuit branches, each capacitive circuit branch comprising a partial capacitive component, a capacitive branch switch, and a control circuit driving the capacitive branch switch.

[0026] According to one possibility, each resistive branch switch and each capacitive branch switch is a transistor made from a semiconductor material, for example from CMOS type technology.

[0027] According to one possibility, each resistive branch switch and each switch The capacitive branch is an NMOS, PMOS, or dual MOS type transistor.

[0028] According to one embodiment, the calculation unit regulates the resistance value of the resistive component by controlling the opening and closing of each resistive branch switch in each resistive circuit branch.

[0029] According to one embodiment, the calculation unit sets the capacitance value of the capacitive component by controlling the opening and closing of each capacitive branch switch in each capacitive circuit branch.

[0030] Advantageously, the partial resistive component has a resistance value significantly higher than the conduction resistance of the switch so as to guarantee a stable gain value of the amplification component despite temperature variations. The resistance value of the partial resistive component can, for example, be more than 20 times greater than the conduction resistance of the switch.

[0031] The digital adjustment control can be applied through a communication bus, for example a low-speed communication bus of the I2C or SPI type, linking the computing unit and the control circuit of the resistive branch switch and between the computing unit and the control circuit of the capacitive branch switch.

[0032] The resistive component and the capacitive component can be integrated into a semiconductor material substrate.

[0033] According to one possibility, the semiconductor material can be raw silicon or Silicon on Insulator or SOI.

[0034] The resistive component and the capacitive component can be made from CMOS or BiCMOS type technology.

[0035] The present invention also relates to a conversion device capable of converting an input electrical current into an output electrical voltage, comprising a photonic sensor and the described integrated electronic circuit, said photonic sensor being connected to said integrated circuit and said input electrical current being supplied by the photonic sensor.

[0036] The photonic sensor may include at least one photodiode.

[0037] Advantageously, the fact that the bias current value is adjustable, the fact that the resistive component has an ability to modify the resistance value and the fact that the capacitive component has an ability to modify the capacitance value, allow the conversion device to be used with a photodiode, or photonic diode, having a junction capacitance varying in a wide range of junction capacitances, for example between IpF and 20pF.

[0038] Advantageously, the ability to modify the bias current value allows for adjusting the bandwidth of the amplification component as a function of a capacitance value of the photodiode, the resistance value of the resistive component and the capacitance value of the capacitive component.

[0039] According to one possibility, the photonic sensor can be a phototransistor, a PIN type photodiode, or an avalanche type photodiode.

[0040] According to one possibility, the conversion device includes a digitizing component and the output port of the amplification component is electrically connected to the digitizing component.

[0041] The digitization component can, for example, be an analog-to-digital converter capable of digitizing the electrical output voltage present at the output of the conversion device.

[0042] The output port of the amplification component can be directly linked to the digitizing component.

[0043] According to an alternative, the output port of the amplification component can be connected to an electronic filter which is connected to the digitizing component, the electronic filter being intended to avoid aliasing of the output signal of the amplification component, in other words to restrict the bandwidth of the output signal in order to satisfy a sampling theorem such as the Nyquist-Shannon theorem.

[0044] The present invention also relates to a method for determining the resistance value present between the first terminal and the second terminal of the resistive component, a method in which the resistive component is an integral part of the described integrated electronic circuit and provides the ability to modify said resistance value in situ without removing the resistive component from the integrated electronic circuit, a method in which the digital adjustment control belonging to the integrated electronic circuit comprises:

[0045] - the component for detecting a limit value of an output signal mentioned above in level of the output port of the amplification component that belongs to the integrated electronic circuit;

[0046] - the aforementioned computing unit connected to the detection component and arranged to adjust the resistance value of the resistive component and capacitance value of the capacitive component belonging to the integrated electronic circuit so as to set a value of a characteristic relative to the amplification component when the limit value of the output signal is detected by the detection component;

[0047] the process comprising the following steps:

[0048] - detection, by the detection component, of the limit value of the output signal at the level of the output port of the amplification component; - modification of an output value of the detection component based on the limit value of the output signal at the output port of the amplification component; - transmission of the output value from the detection component to the processing unit.

[0049] According to one possibility, in the method for determining a resistance value, the resistive component of the integrated electronic circuit comprises a plurality of resistive circuit branches, each resistive circuit branch comprising the partial resistive component, the resistive branch switch, and the control circuit driving the resistive branch switch,

[0050] the process comprising the following steps:

[0051] - transmission, by the computing unit, of a control signal for the switch resistive branch controlled by the resistive branch switch control circuit;

[0052] - actuation of the resistive branch switch based on the signal of command sent by the computing unit; and

[0053] - modification of the resistance value of the resistive component as a function of the resistive branch switch activated.

[0054] The invention also relates to a method for determining a capacitance value present between a first terminal and a second terminal of a capacitive component, a method in which the capacitive component is an integral part of a described integrated electronic circuit and provides the ability to modify said capacitance value in situ without removing the capacitive component from the integrated electronic circuit, a method in which the capacitive component comprises a plurality of capacitive circuit branches, each capacitive circuit branch comprising a partial capacitive component, a capacitive branch switch, and a control circuit driving the capacitive branch switch,

[0055] the process comprising the following steps:

[0056] - determination, by the aforementioned calculation unit, of a value of a bandwidth relative to the integrated electronic circuit; - transmission, by the computing unit, of a control signal for the capacitive branch switch driven by the capacitive branch switch control circuit based on the determined bandwidth value; - actuation of the capacitive branch switch based on the control signal sent by the computing unit; and - modification of the capacitance value associated with the capacitive component depending on the capacitive branch switch that is activated.

[0057] According to one embodiment, the determination of the value of the bandwidth relative to the integrated electronic circuit is done as a function of the value of the resistance of the resistive component, the capacitance of the input photonic sensor and an input capacitance of the amplification component. Brief description of the drawings

[0058] The invention will be better understood with the aid of the detailed description set forth below in relation to the accompanying drawings in which:

[0059] [Fig. 1] is a schematic representation of an electrical circuit of a first embodiment of a conversion device capable of converting an input electrical current into an output electrical voltage comprising an integrated circuit including an amplification component, a resistive component having a variable resistance value and a capacitive component having a variable value capacitance.

[0060] [Fig.2] is a schematic representation of an electrical circuit of a second embodiment of the conversion device of [Fig.1] comprising several amplification components having differential inputs.

[0061] [Fig.3] is a schematic representation of an electrical circuit of a third embodiment of the conversion device of [Fig.1] comprising an amplification component and a transistor used to amplify an input signal of said conversion device.

[0062] [Fig.4] is a flowchart showing different steps carried out during the implementation of a process for determining a resistance value of the resistive component included in the integrated circuit of the conversion device of the [Fig.1].

[0063] [Fig. 5] is a flowchart showing different steps performed during the implementation of a method for determining the capacitance value of the capacitive component included in the integrated circuit of the conversion device [Fig. 1]. Detailed description

[0064] In the detailed description that follows of the figures defined above, the same elements or elements performing identical functions may retain the same reference numerals in order to simplify understanding of the invention. Integrated electronic circuit

[0065] The object of the invention is, firstly, an integrated electronic circuit comprising an amplification component OA having at least one input port IN and one output port OUT, the amplification component OA being characterized by a bias current value Ib, the bias current value Ib being modifiable in situ without removing the amplification component OA from the integrated electronic circuit. The amplification component OA may in particular designate an operational amplifier and said operational amplifier may have a single input, in other words have a single input port as is the case in Figures 1 and 3, or a differential input, in other words have two input ports as is the case in [Fig. 2].

[0066] The integrated electronic circuit also includes a resistive component Rf having a first terminal electrically connected to the input port IN of the amplification component OA and a second terminal electrically connected to the output port OUT of the amplification component OA, the resistive component Rf having a resistance value considered between its first terminal and its second terminal and conferring an ability to modify said resistance value in situ without removing the resistive component from the integrated electronic circuit.

[0067] Advantageously, the resistive component Rf allows adjustment of a gain of the amplification component, in particular of the operational amplifier.

[0068] The integrated electronic circuit also includes a capacitive component Cf having a first terminal electrically connected to the input port IN of the amplification component OA and a second terminal electrically connected to the output port OUT of the amplification component OA, the resistive component Rf and the capacitive component Cf being electrically arranged in a parallel arrangement with respect to each other, the capacitive component Cf having a capacitance value between its first terminal and its second terminal and conferring an ability to modify said capacitance value in situ without removing the capacitive component Cf from the integrated electronic circuit.

[0069] Advantageously, the resistive component Rf and the capacitive component Cf allow, thanks to their respective abilities to adjust the resistance value and the capacitance value, to avoid the use of an external adjustment component to the integrated electronic circuit described here.

[0070] The resistive component Rf and the capacitive component Cf are integrated into a substrate made of semiconductor material.

[0071] According to one possibility, the semiconductor material can be raw silicon or Silicon on Insulator or SOI.

[0072] The resistive component Rf and the capacitive component Cf are made using CMOS or BiCMOS technology.

[0073] The integrated electronic circuit also includes a digital adjustment control capable of determining the following three values: the modifiable resistance value of the resistive component Rf, the modifiable capacitance value of the capacitive component Cf and the modifiable bias current value Ib of the amplification component OA.

[0074] Advantageously, the ability to modify the bias current value Ib allows for adjustment of the noise of the amplification component AO.

[0075] Advantageously, the ability to modify the bias current value Ib allows adjustment of the consumption of the amplification component OA.

[0076] The digital adjustment control includes a component for detecting a limit value Vpp of an output signal Vo at the output port OUT of the amplification component OA, the detection component being, for example, a circuit for detecting a peak-to-peak voltage value.

[0077] The output signal Vo can be an electrical voltage, for example, which will be injected into an ADC conversion circuit of an analog signal to a digital signal, also called a digitization circuit or analog-to-digital converter.

[0078] The digital adjustment control also includes a calculation unit connected to the detection component and arranged to adjust the resistance value of the resistive component Rf and the capacitance value of the capacitive component Cf so as to adjust a value of a characteristic relating to the amplification component OA, for example the gain of the amplification component OA, in particular of the operational amplifier, when the limit value of the output signal Vo is detected by the detection component.

[0079] The calculation unit can for example be a microcontroller connected to the detection circuit and configured to adjust the resistance value of the resistive component Rf and / or the capacitance value of the capacitive component Cf.

[0080] The limit value Vpp of the output signal can designate a peak-to-peak value of the output voltage having a predefined value, for example 1.1V, the limit value being defined so as to avoid saturation of the analog signal in the analog-to-digital converter.

[0081] In the described integrated electronic circuit, the resistive component Rf comprises a plurality of resistive circuit branches BR, each resistive circuit branch BR comprising a partial resistive component Rfi (Rfl, Rf2,.. .Rf5) shown in [Fig.2], a resistive branch switch Int-R, and a control circuit driving the resistive branch switch Int-R.

[0082] Advantageously, the partial resistive component Rfi has a resistance value significantly higher than the conduction resistance of the resistive branch switch Int-R, so as to guarantee the stability of the gain value of the amplification component OA despite temperature variations. The resistance value of the partial resistive component Rfi can, for example, be more than 20 times greater than the conduction resistance of the resistive branch switch Int-R.

[0083] In the described integrated electronic circuit, the capacitive component Cf comprises a plurality of capacitive circuit branches BC, each capacitive circuit branch BC comprising a partial capacitive component Cfi (Cfl, Cf2, Cf3) shown in [Fig.2], a capacitive branch switch Int-C, and a control circuit driving the capacitive branch switch Int-C.

[0084] According to one possibility, each resistive branch switch Int-R and each capacitive branch switch Int-C is a transistor made from a semiconductor material, for example from CMOS-type technology.

[0085] According to one possibility, each resistive branch switch Int-R and each capacitive branch switch Int-C is an NMOS type transistor, a PMOS type transistor or dual MOS type

[0086] According to one embodiment, the calculation unit sets the resistance value of the resistive component Rf by controlling the opening and closing of each resistive branch switch Int-R in each resistive circuit branch BR.

[0087] According to one embodiment, the calculation unit regulates the capacitance value of the capacitive component Cf by controlling the opening and closing of each capacitive branch switch Int-C in each capacitive circuit branch BC.

[0088] The digital adjustment control is applied through a communication bus, for example a low-speed communication bus of the I2C or SPI type, linking the computing unit and the control circuit of the resistive branch switch Int-R and between the computing unit and the control circuit of the capacitive branch switch Int-C. Conversion device: composition

[0089] The invention also relates to a conversion device capable of converting an input electrical current Id into an output electrical voltage Vo, or commonly called a transimpedance amplifier, comprising a photonic sensor or photodetector D and the integrated electronic circuit described above, said photonic sensor D being connected to said integrated circuit and said input electrical current Id being supplied by the photonic sensor D.

[0090] The photonic sensor D may include at least one photodiode.

[0091] According to one possibility, the photonic sensor D can be a phototransistor, a PIN type photodiode, or an avalanche type photodiode.

[0092] The conversion device or transimpedance amplifier, one embodiment of which is shown in [Fig. 1], is remarkable in that it integrates the previously described integrated circuit; in other words, it is possible to modify the value of the resistance of the resistive component Rf as well as the value of the capacitance of the capacitive component Cf and that of the bias current Ib of the amplification component OA or operational amplifier in order to modify or adjust certain characteristics of the transimpedance amplifier such as a gain, a bandwidth, a power consumption or even an operating noise.

[0093] Advantageously, the fact that the bias current value Ib is adjustable, the fact that the resistive component Rf has an ability to modify the resistance value and the fact that the capacitive component Cf has an ability to modify the capacitance value, allow the conversion device to be used with a photodiode, or photonic diode, having a junction capacitance Cd varying in a wide range of junction capacitances, for example between IpF and 20pF.

[0094] Thus, a change in the resistance value of the resistive component Rf and a change in the capacitance value of the capacitive component Cf can compensate for a variation of the junction capacitance Cd of the photodiode due to external factors such as a variation in room temperature for example or internal factors such as aging of the photodiode for example.

[0095] The value of the resistance of the resistive component Rf is related to the output electrical voltage Vo and the input electrical current Id by equation [Math 1].

[0096] [Math.l] Vmax - Vmin ~ Z.Id

[0097] The quantities Vmax and Vmin are shown in [Fig. 1] and respectively denote a maximum and a minimum value of the output voltage Vo of the transimpedance amplifier. Thus, if the values ​​of Vmax, Vmin and Id are known, it is possible to calculate the value of the resistance of the resistive component Rf according to [Math 1].

[0098] Moreover, and advantageously, the fact that the bias current value Ib is adjustable, the fact that the resistive component Rf has an ability to modify the resistance value and the fact that the capacitive component Cf has an ability to modify the capacitance value, allow the conversion device to be used with several types of photodiodes having different junction capacitance values ​​Cd.

[0099] Advantageously, the ability to modify the bias current value Ib allows a bandwidth adjustment of the amplification component OA as a function of a capacitance value of the photodiode Cd, the resistance value of the resistive component Rf and the capacitance value of the capacitive component Cf.

[0100] The value of the bias current Ib is related to the junction capacitance of the photodiode Cd, to an input capacitance Cp of the amplification component OA, to a bandwidth fc of the amplification component OA and to a constant VT according to equation [Math 2].

[0101] [Math.2] Ib- fc2Am\Cp.(Cd + Cp).VT

[0102] Thus, by fixing an operating value of the bandwidth fc of the amplification component and knowing the values ​​of the junction capacitance Cd of the photodiode and the input capacitance Cp of the amplification component OA, we can determine the value of the bias current Ib.

[0103] The input capacitance Cp of the amplification component OA may be entirely or partially constituted by a parasitic input capacitance of the amplification component OA.

[0104] The value of the capacitance of the capacitive component Cf is related to the junction capacitance Cd of the photodiode, the input capacitance Cp of the amplification component, the value of the resistance of the resistive component Rf, and a product of the band bandwidth of the amplification component by a gain of the amplification component more commonly called the gain-band product GBW of the amplification component according to equation [Math 3].

[0105] [Math.3] rf I Cd + Cp L J Vr. GBW. Rf

[0106] Knowing the value of the resistance of the resistive component Rf, that of the junction capacitance Cd of the photodiode, the input capacitance Cp of the amplification component OA and by fixing a value of the desired gain-bandwidth product GBW, one can calculate the value of the capacitance of the capacitive component Cf.

[0107] Equation [Math 3] can also represent a dimensioning criterion for the conversion device which must be satisfied in order to guarantee stability of the described conversion device during its operation.

[0108] The conversion device may include an ADC digitizing component and the OUT output port of the OA amplification component may be electrically connected to the ADC digitizing component.

[0109] The ADC digitization component can, for example, be an analog-to-digital converter capable of digitizing the electrical output voltage Vo present at the output of the conversion device OA.

[0110] The OUT output port of the OA amplifier component can be directly linked to the ADC digitizing component.

[0111] According to an alternative, the output port OUT of the amplification component OA can be connected to an electronic filter which is connected to the digitizing component ADC, the electronic filter being intended to avoid aliasing of the output signal of the amplification component, in other words to restrict the bandwidth of the output signal in order to satisfy a sampling theorem such as the Nyquist-Shannon theorem. Conversion device: operation

[0112] According to a first embodiment shown in [Fig.1], radiation L is detected by the photodetector D which converts the radiation L into the electric current Id.

[0113] This electric current Id is injected into the conversion device comprising the amplification component OA as well as the integrated circuit described among others.

[0114] The conversion device then converts the electrical current Id into the output voltage Vo. The output voltage Vo, which can be sinusoidal and which has the peak-to-peak value Vpp, the minimum value Vmin and the maximum value Vmax, is intended to be used in a given application.

[0115] The output voltage Vo is then injected, either directly or through an anti-filter folding, in the ADC digitization device or analog-to-digital converter to be converted into a digital signal intended for use.

[0116] During operation of the described conversion device, factors internal or external to the conversion device may, for example, alter the value of the junction diode Cd of the photodiode, which could destabilize the conversion device. To avoid this risk of destabilization or erroneous operation of the conversion device, it is possible to program or adjust the resistance values ​​of the resistive component Rf, the capacitance of the capacitive component Cf, and the bias current Ib of the amplification component OA.

[0117] The resistance values ​​of the resistive component Rf, the capacitance of the capacitive component Cf and the bias current Ib of the amplification component OA can be modified together or each separately according to the needs of the intended application.

[0118] The resistance value of the resistive component Rf is determined and modified according to a method for determining a resistance value described below.

[0119] Similarly, the capacitance value of the resistive component Cf is determined and modified according to a capacitance value determination method described below.

[0120] It is possible to carry out the conversion device having the same operation as that described above according to a second embodiment presented in [Fig.2], where the conversion device includes a plurality of differential amplifier components OAD as well as the integrated circuit described among others.

[0121] It is also possible to carry out the conversion device having the same operation as that described above according to a third embodiment presented in [Fig.3], where the electrical current Id at the input is injected into a transistor T in order to be amplified before being injected into the amplification component OA and being converted by said amplification component OA into the output voltage Vo which will be digitized by the digitization device ADC.

[0122] Method for determining a resistance value

[0123] The invention also relates to the method of determining a resistance value present between the first terminal and the second terminal of the resistive component Rf, in which the resistive component Rf is an integral part of the integrated electronic circuit described above and provides the ability to modify said resistance value in situ without removing the resistive component Rf from the integrated electronic circuit, in which the digital adjustment control belonging to the integrated electronic circuit comprises:

[0124] - the component for detecting a limit value of an output signal Vo at the level of the output port OUT of the OA amplifier component which belongs to the integrated electronic circuit;

[0125] - the aforementioned computing unit connected to the detection component and arranged to adjust the resistance value of the resistive component Rf and capacitance value of the capacitive component Cf which belongs to the integrated electronic circuit so as to adjust the value of the characteristic relating to the amplification component OA when the limit value of the output signal Vo is detected by the detection component;

[0126] the process comprising the following steps shown in [Fig.4]:

[0127] - Detection SI, by the detection component, of the limit value of the output signal Vo at the output port OUT of the amplification component OA; - modification S2 of an output value of the detection component based on the limit value Vpp of the output signal Vo at the output port OUT of the amplification component OA; - S3 transmission of the output value from the detection component to the processing unit.

[0128] - transmission S4, by the computing unit, of the control signal of the switch resistive branch Int-R controlled by the control circuit of the resistive branch switch BR;

[0129] - actuation S5 of the resistive branch switch Int-R based on the signal of command sent by the computing unit; and

[0130] - modification S6 of the resistance value of the resistive component Rf as a function of the resistive branch switch Int-R activated.

[0131] According to one possibility, only one resistive branch switch Int-R is actuated and in this case the value of the resistance of the resistive component Rf is given by a resistance value of a single partial resistive component Rfi.

[0132] According to another possibility, several resistive branch switches Int-R are actuated at the same time and in this case the value of the resistance of the resistive component Rf is given by a resistance value resulting from the combination of several partial resistive components, for example the resistance value resulting from the parallel connection of two partial resistive components. Method for determining a capacity value

[0133] The invention further relates to a method for determining a capacitance value present between the first terminal and the second terminal of the capacitive component Cf, wherein the capacitive component Cf is an integral part of the previously described integrated electronic circuit and provides the ability to modify said capacitance value in situ without removing the capacitive component Cf from the integrated electronic circuit, wherein the capacitive component Cf comprises a plurality of capacitive circuit branches BC, each capacitive circuit branch BC comprising a partial capacitive component Cfi, a capacitive branch switch Int-C, and a control circuit driving the capacitive branch switch Int-C, the process comprising the following steps shown in [Fig. 5]:

[0134] - Determination SI', by the aforementioned calculation unit, of a value of a bandwidth relative to the integrated electronic circuit; - Transmission S2', by the computing unit, of the control signal of the capacitive branch switch Int-C driven by the control circuit of the capacitive branch switch Int-C on the basis of the determined bandwidth value; - actuation S3' of the Int-C capacitive branch switch based on the control signal sent by the computing unit; and - modification S4' of the capacitance value associated with the capacitive component Cf as a function of the capacitive branch switch Int-C being activated.

[0135] According to one embodiment, the determination of the value of the bandwidth relative to the integrated electronic circuit is done as a function of the value of the resistance of the resistive component Rf, the capacitance of the photonic sensor D at the input and the input capacitance of the amplification component Cp.

[0136] According to one possibility, only one capacitive branch switch Int-C is actuated and in this case the value of the capacitance of the capacitive component Cf is given by a capacitance value of a single partial capacitive component Cfi.

[0137] According to another possibility, several Int-C capacitive branch switches are actuated at the same time and in this case the value of the capacitance of the capacitive component Cf is given by a capacitance value resulting from the combination of several partial capacitive components, for example the capacitance value resulting from the paralleling of two partial capacitive components.

[0138] Although the invention has been described in connection with particular examples of embodiment, it is clearly evident that it is by no means limited to them and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

Claims

Demands

1. A conversion device capable of converting an input electrical current (Id) into an output electrical voltage (Vo), comprising a photonic sensor (D) and an integrated electronic circuit, said photonic sensor (D) being connected to said integrated electronic circuit, and the integrated electronic circuit comprising: - an amplification component (OA) comprising at least one input port (IN) and one output port (OUT), the amplification component (OA) being characterized by a bias current value (Ib), the bias current value (Ib) being modifiable in situ without removing the amplification component (OA) from the integrated electronic circuit; - a resistive component (Rf) having a first terminal electrically connected to the input port (IN) of the amplification component (OA) and a second terminal electrically connected to the output port (OUT) of the amplification component (OA), the resistive component (Rf) having a resistance value considered between its first terminal and its second terminal and conferring an ability to modify said resistance value in situ without removing the resistive component from the integrated electronic circuit; - a capacitive component (Cf) having a first terminal electrically connected to the input port (IN) of the amplification component (OA) and a second terminal electrically connected to the output port (OUT) of the amplification component (OA), the resistive component (Rf) and the capacitive component (Cf) being electrically arranged in a parallel arrangement with respect to each other, the capacitive component (Cf) having a capacitance value between its first terminal and its second terminal and conferring an ability to modify said capacitance value in situ without removing the capacitive component (Cf) from the integrated electronic circuit; And - a digital adjustment control capable of determining the three following values: the modifiable resistance value of the resistive component (Rf), the modifiable capacitance value of the capacitive component (Cf) and the modifiable bias current value (Ib) of the amplification component (OA) the digital adjustment control comprising: - a component for detecting a limit value of an output signal (Vo) at the output port (OUT) of the amplification component (OA);- a computing unit connected to the sensing component and arranged to adjust the resistance value of the resistive component (Rf) and the capacitance value of the capacitive component (Cf) so as to set a value of a characteristic relative to the amplification component (OA) when the limit value of the output signal (Vo) is detected by the sensing component, the digital adjustment control being applied through a communication bus linking the computing unit and a control circuit of a resistive branch switch (Int-R) and between the computing unit and a control circuit of a capacitive branch switch (Int-C); said input electrical current (Id) being supplied by the photonic sensor (D), the photonic sensor (D) comprising at least one photodiode.;

2. Conversion device according to claim 1, wherein the resistive component (Rf) comprises a plurality of resistive circuit branches (BR), each resistive circuit branch (BR) comprising a partial resistive component (Rfi), a resistive branch switch (Int-R), and a control circuit driving the resistive branch switch (Int-R).

3. Conversion device according to any one of the preceding claims, wherein the capacitive component (Cf) comprises a plurality of capacitive circuit branches (BC), each capacitive circuit branch (BC) comprising a partial capacitive component (Cfi), a capacitive branch switch (Int-C), and a control circuit driving the capacitive branch switch (Int-C).

4. Conversion device according to any one of the preceding claims, wherein the resistive component (Rf) and the capacitive component (Cf) are integrated into a substrate of semiconductor material.

5. Conversion device according to any one of the preceding claims, wherein the resistive component (Rf) and the capacitive component (Cf) are made from CMOS or BiCMOS type technology.

6. Conversion device according to any one of the preceding claims, wherein the conversion device comprises a digitizing component (ADC) and wherein the output port (OUT) of the amplification component (OA) is electrically connected to the digitizing component (ADC).

7. Method of determining a resistance value present between a first terminal and a second terminal of a resistive component (Rf), method in which the resistive component is an integral part of an integrated electronic circuit included in a conversion device according to any one of claims 1 to 6 and provides the ability to modify said resistance value in situ without removing the resistive component (Rf) from the integrated electronic circuit, method in which the digital adjustment control which belongs to the integrated electronic circuit comprises: - a component for detecting a limit value of an output signal (Vo) at the output port (OUT) of the amplification component (OA) which belongs to the integrated electronic circuit;- a calculation unit connected to the detection component and arranged to adjust the resistance value of the resistive component (Rf) and the capacitance value of the capacitive component (Cf) belonging to the integrated electronic circuit so as to set a value of a characteristic relating to the amplification component (OA) when the limit value of the output signal (Vo) is detected by the detection component; the method comprising the following steps: - Detection (SI), by the detection component, of the limit value of the output signal (Vo) at the output port (OUT) of the amplification component (OA); - modification (S2) of an output value of the detection component based on the limit value (Vpp) of the output signal (Vo) at the output port (OUT) of the component; amplification (OA); transmission (S3) of the output value of the detection component to the computing unit.

8. Method for determining a resistance value according to the reven Indication 7, wherein the resistive component (Rf) of the integrated electronic circuit comprises a plurality of resistive circuit branches (BR), each resistive circuit branch (BR) comprising a partial resistive component (Rfi), a resistive branch switch (Int-R), and a control circuit driving the resistive branch switch (Int-R), the method comprising the following steps: - transmission (S4), by the computing unit, of a control signal for the resistive branch switch (Int-R) controlled by the control circuit for the resistive branch switch (BR); - actuation (S5) of the resistive branch switch (Int-R) based on the control signal sent by the computing unit; and - modification (S6) of the value of the resistance of the resistive component (Rf) as a function of the resistive branch switch (Int-R) being activated.

9. Method for determining a capacitance value present between a first terminal and a second terminal of a capacitive component (Cf), a method in which the capacitive component (Cf) is an integral part of an integrated electronic circuit included in a conversion device according to any one of claims 1 to 6 and provides the ability to modify said capacitance value in situ without removing the capacitive component (Cf) from the integrated electronic circuit, a method in which the capacitive component (Cf) comprises a plurality of capacitive circuit branches (BC), each capacitive circuit branch (BC) comprising a partial capacitive component (Cfi), a capacitive branch switch (Int-C), and a control circuit driving the capacitive branch switch (Int-C), the method comprising the following steps: Determination (S1), by a computing unit, of a bandwidth value relative to the integrated electronic circuit; Transmission (S2'), by the computing unit, of a control signal for the capacitive branch switch (Int-C) driven by the capacitive branch switch control circuit (Int-C) based on the bandwidth value determined; actuation (S3') of the capacitive branch switch (Int-C) based on the control signal sent by the computing unit; and modification (S4') of the capacitance value associated with the capacitive component (Cf) as a function of the capacitive branch switch (Int-C) being actuated.

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