CN114089804A

CN114089804A - Apparatus and method for powering electronic circuits

Info

Publication number: CN114089804A
Application number: CN202110973508.XA
Authority: CN
Inventors: N·德曼吉; N·博瑞尔; J·弗特
Original assignee: STMicroelectronics Rousset SAS
Current assignee: STMicroelectronics Rousset SAS
Priority date: 2020-08-25
Filing date: 2021-08-24
Publication date: 2022-02-25
Anticipated expiration: 2041-08-24
Also published as: CN114089804B

Abstract

Embodiments of the present disclosure relate to apparatus and methods for powering electronic circuits. An embodiment electronic circuit power supply device is configured to: flowing a first current through a first conductor connected to a node, the first current being a mirror of a second current consumed by the electronic circuit; flowing a third current through a second conductor connected to the node; adjusting the potential of the node to a constant value by acting on the third current; flowing a fourth constant current through a third conductor connected to the node; and consuming a fifth current that is a mirror image of the third current.

Description

Apparatus and method for powering electronic circuits

Cross Reference to Related Applications

The present application claims the benefit of french patent application No.2008673, filed on 25/8/2020, which is incorporated herein by reference.

Technical Field

The present disclosure relates generally to electronic devices and methods, and in particular, to electronic circuit power supply devices and methods.

Background

The electronic circuit may be integrated in an electronic chip. A chip typically includes an electronic circuit power supply device having the function of delivering a voltage from a power supply voltage of the chip to the electronic circuit. The electronic circuit consumes a variable current depending on its operation. The voltage delivered to the circuit is typically stabilized or regulated so that it remains at a constant value during variations in the current consumed by the circuit.

The electronic circuit may contain confidential data that may be protected from any access by unauthorized persons. This occurs, for example, when the chip is intended to receive, store and/or communicate a password or encrypted data, such as a key. The attacker may then attempt to obtain all or part of the confidential data.

In one attack, an attacker operates the chip and attempts to measure the current supplied to the electronic circuit power supply device in order to extract information about the operation of the electronic circuit from which confidential information can be inferred based on changes in this current.

Disclosure of Invention

There is a need for an apparatus and method for powering electronic circuits containing confidential data so that the confidential data can be protected from attack.

There is a need to simplify existing electronic circuit power supply apparatus and methods.

Embodiments overcome all or part of the disadvantages of known electronic circuit power supply devices.

Embodiments overcome all or part of the disadvantages of known electronic circuit power supply approaches.

According to a first aspect, embodiments provide an apparatus for powering electronic circuitry, the apparatus being configured to: flowing a first current through a first conductor connected to the node, the first current being a mirror of a second current consumed by the electronic circuit; flowing a third current through a second conductor connected to the node, the first branch of the current mirror conducting the third current; flowing a fourth constant current through a third conductor connected to the node; consuming a fifth current that is a mirror of the third current; and adjusting the potential of the node by acting on the gate potential of a transistor electrically in series with the second branch of the current mirror.

An embodiment provides a method of powering an electronic circuit, the method comprising the steps of: flowing a first current through a first conductor connected to the node, the first current being a mirror of a second current consumed by the electronic circuit; flowing a third current through a second conductor connected to the node, the first branch of the current mirror conducting the third current; flowing a fourth constant current through a third conductor connected to the node; consuming a fifth current that is a mirror of the third current; and adjusting the potential of the node by acting on the gate potential of a transistor electrically in series with the second branch of the current mirror.

According to an embodiment, the transistor couples the node to which the potential is applied (preferably fixed) to the gate of the transistor of the current mirror that is coupled together.

According to an embodiment, the transistor is smaller than the transistor of the second branch of the current mirror.

According to an embodiment, the potential of the node is regulated to a constant value.

According to an embodiment, the resistive element conducts the fourth current.

According to an embodiment, the constant value is a value of a regulation potential for powering the electronic circuit.

According to an embodiment, the first branch of the further current mirror conducts a first current; and the potential of the node is adjusted to the potential value of the terminal of the second branch of the other current mirror.

According to an embodiment, the operational amplifier receives a potential difference between the node and the terminal of the second branch of the further current mirror and acts on the gate potential of the transistor.

According to an embodiment, the second branch of the further current mirror is in electrical series with the electronic circuit between the terminal to which the supply voltage referenced to the reference potential is applied and the terminal to which the reference potential is applied.

According to an embodiment, the fifth current is supplied by a terminal to which the power supply voltage is applied.

According to an embodiment, the terminal of the second branch of the current mirror has a potential adjusted to the value of the potential of the node.

According to an embodiment, an additional transistor is connected in series with the second branch of the current mirror; and the additional transistor is controlled by the output of an operational amplifier receiving the difference between the potential at the node and the potential of the terminal of the second branch of the current mirror.

According to an embodiment, a ratio between values of the fifth current and the third current is equal to another ratio between values of the second current and the first current or to a sum of the another ratio and the unit element.

Embodiments provide electronic circuits comprising devices and electronic circuits such as defined above, or configured to implement methods such as defined above.

According to a second aspect, embodiments provide an electronic circuit power supply device configured to: flowing a first current through a first conductor connected to the node, the first current being a mirror of a second current consumed by the electronic circuit; flowing a third current through a second conductor connected to the node; adjusting the potential of the node to a constant value by acting on the third current; flowing a fourth constant current through a third conductor connected to the node; and consuming a fifth current that is a mirror of the third current.

An embodiment provides an electronic circuit power supply method, which includes the following steps: flowing a first current through a first conductor connected to the node, the first current being a mirror of a second current consumed by the electronic circuit; flowing a third current through a second conductor connected to the node; adjusting the potential of the node to a constant value by acting on the third current; flowing a fourth constant current through a third conductor connected to the node; and consuming a fifth current that is a mirror of the third current.

According to an embodiment, the resistive element conducts the fourth current.

According to an embodiment, a first branch of a current mirror coupled to a first conductor conducts a first current; and the terminal of the second branch of the current mirror has a potential regulated to a constant value.

According to an embodiment, the second branch of the current mirror is in electrical series with the electronic circuit between the terminal to which the supply voltage referenced to the reference potential is applied and the terminal to which the reference potential is applied.

According to an embodiment, the first branch of the current mirror coupled to the second conductor conducts a third current; a second branch of the current mirror coupled to the second conductor consumes a fifth current; and the potential of the node is adjusted by the action on the potential of the gates coupled together of the transistors of the current mirror coupled to the second conductor.

According to an embodiment, the action on the potential of the gate is performed by an operational amplifier receiving a potential difference between the node and a terminal of the second branch of the current mirror coupled to the first conductor.

According to an embodiment, the effect on the potential of the gate is obtained by a control potential acting on a further transistor electrically in series with the second branch of the current mirror coupled to the second conductor; and preferably the further transistor has a gate coupled to a further node to which the supply potential is applied.

According to an embodiment, the further transistor is smaller than the transistor of the second branch of the current mirror coupled to the second conductor.

According to an embodiment, the terminal of the second branch of the current mirror coupled to the second conductor has a potential adjusted to a constant value.

According to an embodiment, the additional transistor is in series with a second branch of the current mirror coupled to the second conductor; and the additional transistor is controlled by an output of an operational amplifier configured to amplify a difference between the constant value and a potential of a terminal of the second branch of the current mirror coupled to the second conductor.

Embodiments provide an electronic chip comprising an apparatus and an electronic circuit such as defined above, or configured to implement a method such as defined above.

Drawings

The foregoing features and advantages, and other features and advantages, will be described in detail in the following description of specific embodiments, given by way of illustration and not limitation, with reference to the accompanying drawings, in which:

FIG. 1 schematically illustrates an example of an electronic circuit power supply apparatus of the type to which the described embodiments are applicable;

fig. 2 schematically shows an embodiment of an electronic circuit power supply apparatus according to the first aspect;

fig. 3 schematically shows an embodiment of an electronic circuit power supply apparatus according to a second aspect; and

fig. 4 schematically shows an embodiment of an electronic circuit power supply apparatus combining the first and second aspects.

Detailed Description

Like features have been indicated by like reference numerals in the various drawings. In particular, structural and/or functional features that are common between the various embodiments may have the same reference numerals and may accommodate the same structural, dimensional, and material properties.

For clarity, only the steps and elements useful for understanding the embodiments described herein are illustrated and described in detail. In particular, the electronic circuit powered by the supply voltage is not described in detail, the described embodiments being compatible with usual electronic chip circuits.

Unless otherwise indicated, when two elements are referred to as being connected together, this means that there is no direct connection of any intervening elements other than conductors; and when two elements are referred to as being coupled together, this means that the two elements can be connected or they can be coupled via one or more other elements.

In the following disclosure, unless otherwise specified, when referring to absolute position modifiers (such as the terms "front", "back", "top", "bottom", "left", "right", etc.) or relative position modifiers (such as the terms "above", "below", "higher", "lower", etc.) or orientation modifiers (such as "horizontal", "vertical", etc.), the orientations shown in the figures are referred to.

Unless otherwise specified, the expressions "about", "approximately", "substantially" and "approximately" mean within 10%, and preferably within 5%.

The described embodiments include transistors of the so-called metal oxide semiconductor, MOS, type. Although the term MOS type was originally used to indicate a transistor having a metal gate and an oxide gate insulator, due to the development of this type of transistor, the MOS type is now understood to encompass a field effect transistor having a gate made of any electrical conductor and having a gate insulator made of any dielectric or electrical insulator.

Fig. 1 schematically shows an example of a power supply device 100 for an electronic circuit 110 (circuit) of the type to which the described embodiment is applicable.

The power supply device 100 and the electronic circuit 110 are typically included within an electronic chip. The electronic chip may be in the form of a package, preferably compact, and one or more wafer portions, preferably semiconductors, having the device 100 and circuitry 110 formed on the inside and top thereof. The package comprises connection areas or connection pins for connection to other electronic circuits outside the circuit, such as a printed circuit board PCB. The electronic circuit may also be formed by a wafer portion (preferably a semiconductor, with the device 100 and the circuit 110 located inside and on top).

The circuit 110 may be any type of electronic chip circuit. The circuit 110 may include multiple sub-circuits powered in parallel by the device 100. The electronic chip may also include other electronic circuitry in addition to circuitry 110.

The device 100 comprises an assembly 120 electrically connected in series with the electronic circuit 110 between: a terminal or node 130 to which a supply voltage VCC referenced to a reference potential GND (e.g., ground) is applied; and a terminal or node 132 to which a reference potential GND is applied.

The expression terminal to which a voltage referenced by a reference potential is applied means that the voltage is equal to the difference between the potential applied to the terminal and the reference potential. In other words, the voltage VCC corresponds to the potential applied to the terminal 130. The voltage VCC may be a voltage delivered to the electronic chip for its operation.

Typically, the component 120 is located on one side of the terminal 130 to which the voltage VCC is applied, relative to the circuit 110. For example, the component 120 is connected or coupled to the terminal 130. Further, the component 120 may be coupled (preferably connected) to a terminal 132 to which a reference potential GND is applied.

The component 120 delivers a voltage VDD referenced to the reference potential GND to the circuit 110 on a connection node 134 between the component 120 and the circuit 110. In other words, a voltage VDD with reference to the reference potential GND or the potential VDD is applied to the node 134.

In the example shown, the voltages VCC and VDD are positive. The chip supply voltage VCC is typically in the range of 3.3V to 5V, and the voltage VDD delivered by the component 120 is typically about 1.2V.

Component 120 may comprise a transistor T121, for example of the P-channel MOS type,

coupling nodes

130 and 134. More specifically, transistor T121 has its conductive terminals coupled (preferably connected) to

respective nodes

130 and 134. The term conductive terminals of a transistor refers to terminals of the transistor that are electrically connected together in a conductive state and are electrically insulated from each other in a non-conductive state. In the example shown, transistor T121 has a source terminal (S) coupled (preferably connected) to node 130 and a drain terminal (D) coupled (preferably connected) to node 134.

The component 120 may include an operational amplifier 122 that controls a transistor T121. In other words, in the example in which the transistor T121 is of the MOS type, the transistor T121 has a gate coupled (preferably connected) to the output of the operational amplifier 122. The operational amplifier 122 thus receives the difference between the voltage VDD delivered to the electronic circuit 110 and the potential VDD0 having a constant value (i.e., constant with respect to the potential GND). More specifically, the non-inverting input (+) of the operational amplifier 122 may be coupled (preferably connected) to the node 134, and the inverting input (-) of the operational amplifier 122 may be coupled (preferably connected) to the node to which the constant potential VDD0 is applied. Elements that deliver the potential VDD0 from the voltage VCC are neither described nor shown, and embodiments are compatible with such common elements.

In operation, operational amplifier 122 and transistor T121 regulate (i.e., stabilize) the voltage VDD delivered to circuit 110 to a value equal to the constant value of potential VDD 0. In other words, the operational amplifier 122 acts on the control of the transistor T121 to maintain the voltage VDD delivered to the circuit 110 at a constant value of the potential VDD 0.

Component 120 may include a transistor T123 that forms a current mirror 124 with transistor T121.

Current mirrors indicate circuits comprising two branches arranged such that the current in one of the branches mirrors the current in the other of the branches. Being mirror images of each other means that the values of the currents have a constant ratio. Preferably, the current mirror comprises, and more preferably is formed by, two MOS transistors receiving the same control voltage, having channels of the same conductivity type. In a MOS type transistor, the control voltage means a voltage applied between the gate and the source of the transistor. The transistors of the current mirror are provided, as is usual in current mirrors, so that the current flowing through the transistors passes at a constant rate equal to the size rate of the transistors when the potentials of the drains thereof are equal. Preferably, in the current mirror, the two transistors have their gates coupled together (more preferably connected together) and have their sources coupled together (more preferably connected together). Preferably, in the current mirror, each transistor defines a branch of the current mirror. As a variant, the branches may comprise respective resistors having a predetermined value ratio.

The size ratio between transistors means the ratio of the width (W) to the length (L) of the gate of one transistor relative to the width to the length of the gate of the other transistor.

The component 120 may comprise a transistor T125, for example of the P-channel MOS type. The transistor T125 has, for example, its source coupled (preferably connected) to the drain of the transistor T123. The transistor T125 is controlled by an operational amplifier 126. Operational amplifier 126 receives the potential difference between the drain terminals of transistors T121 and T123 of current mirror 124. More specifically, the operational amplifier 126 receives the drain potential of the transistor T123 on the inverting input (-) and the drain potential of the transistor T121 on the non-inverting input (+).

In operation, the device consumes current I0 supplied by node VCC. The amplifier 126 and the transistor T125 adjust the potential of the drain of the transistor T123 so that the potential of the drain of the transistor T123 is equal to the potential of the drain of the transistor T121. This case makes it possible to obtain in the transistor T123 a current I1 having a value with a constant ratio to the current I2 consumed by the electronic circuit 110. In other words, current I1 is a mirror image of current I2. The currents I1 and I2 verify the equality I1 ═ I2/K124, where K124 indicates a constant and where the currents and their values are indicated in the same way for simplicity. Since the current I0 is the sum of the currents I1 and I2, the currents I0 and I1 then verify the equality I1 as I0/(K124+1), in other words, the current I1 is also a mirror of the current I0. As an example, the constant K124 is in the range of 5 to 200, preferably equal to 100.

Component 120 may also include a transistor T127, such as an N-channel MOS transistor. The transistor T127 has a drain terminal 128 connected or coupled (preferably through a transistor T125) to the drain of the transistor T123. The source of the transistor T127 is coupled (preferably connected) to the terminal 132 to which the reference potential GND is applied. In other words, the transistors T123, T127, and T125 are electrically connected in series between the terminal 130 and the terminal 132. Specifically, transistors T123, T125, and T127 conduct the same current I1. The transistor T127 has its gate coupled together (preferably connected together) with its drain.

Device 100 includes a node 150. The node 150 is coupled to the terminal 132 to which the reference potential GND is applied, via a transistor T145. The transistor T145 may be of an N-channel MOS type. In particular, transistor T145 has a drain terminal coupled (preferably connected) to node 150 and a source terminal coupled (preferably connected) to terminal 132.

N-channel transistors T127 and T145 form a current mirror 146. Drain terminal 128 and node 150 form the terminals of the respective branches of the current mirror.

In operation, the branch of current mirror 146 formed by transistor T145 conducts current I1' originating from node 150.

The device 100 also includes a current source 155 that couples the terminal 130 at which the voltage VCC is applied to the node 150. The current source delivers a constant current I4 to node 150.

The apparatus 100 includes a transistor T160 coupling the node 150 to the terminal 132 to which the reference potential is applied. Transistor T160 may be of the N-channel MOS type, the drain of transistor T160 being coupled (preferably connected) to node 150, and the source of transistor T160 being coupled (preferably connected) to terminal 132.

The device 100 also includes a component 170 that controls the transistor T160. The component 170 couples a terminal 130 to which a voltage VCC is applied and a terminal 132 to which a reference potential GND is applied. The component 170 receives the difference between the potential of the node 150 and the potential of the drain terminal 128 of the transistor T127. In other words, the component 170 receives the difference between the potentials of the terminals of the branches of the current mirror 146.

The component 170 includes a transistor T172 that forms a current mirror 174 with the transistor T160. The transistor T172 may be of the N-channel MOS type. The transistor T172 may have its source coupled (preferably connected) to the terminal 132 to which the reference potential GND is applied. The drain of the transistor T172 may preferably be connected or coupled to the terminal 130, to which the potential VCC is applied, through a transistor T175. Transistor T175 is then connected in series between

terminals

130 and 132 with the branch of current mirror 174 formed by transistor T172.

Preferably, the component 170 includes an operational amplifier 176 that controls the transistor T175. The operational amplifier 176 receives a difference between potentials of the drains of the transistors of the current mirror 174, in other words, the operational amplifier 176 is configured to amplify the difference. For example, the transistor T175 is of the P-channel MOS type, and the operational amplifier 176 has an inverting input (-) coupled (preferably connected) to the node 150 and a non-inverting input (+) coupled (preferably connected) to a node 177 connected to each other with the drains of the transistors T172 and T175. Node 177 defines the terminal of a branch of current mirror 174 formed by transistor T172.

In operation, transistor T160 causes a flow of current I3 from node 150, in other words, transistor T160 conducts current I3. The amplifier 176 and the transistor T175 adjust the potential of the terminal 177 to the value of the potential of the node 150. Thus, the transistor T172 conducts a current I5, which is a mirror of the current I3 and is supplied by the terminal 130, to which the potential VCC is applied.

The apparatus 100 also includes an operational amplifier 178. Operational amplifier 178 receives the potential difference between node 150 and drain terminal 128 of transistor T127. More specifically, operational amplifier 178 has an inverting input (-) coupled (preferably connected) to drain terminal 128 and a non-inverting input (+) coupled (preferably connected) to node 150. Operational amplifier 178 acts on the potentials of the gates of transistors T160 and T172 of current mirror 174, which are coupled together. In other words, the output of the operational amplifier 178 is coupled (preferably connected) to the gates of the transistors T160 and T172.

In operation, operational amplifier 178 adjusts the potential of node 150 to a value equal to the value of the potential of drain terminal 128 by acting on current I3. Thus, current I1' is a mirror image of current I1 by current mirror 146. Due to the fact that the current I1 is a mirror image of the currents I2 and I0, the current I1' is a mirror image of the currents I0 and I2 and has a value ratio of 1/K to the current I0, in other words, the current I1' verifies that the relationship I1' is I0/K. As an example, the current mirror 146 has a current ratio equal to 1. The ratio 1/K may be equal to 1/(K124+1), e.g., equal to 1/101.

Preferably, the transistors T160 and T172 are provided such that the current I5 has a ratio K to the current I3 which is the inverse of the ratio 1/K between the current I1' and the current I0. In other words, the ratio K between the values of the currents I5 and I3 is equal to the sum of the unit element 1 and the ratio K124, the ratio K124 being the ratio between the value of the current I2 consumed by the circuit 110 and the current I1' in the transistor T145. Therefore, the sum I0+ I4+ I5 of the currents I0, I4 and I5 supplied by the terminal 130 remains constant, equal to the value (K +1) × I4, irrespective of the variations in the current I2 consumed by the electronic circuit 110.

Thus, an attacker who searches for variations in the current I0+ I5 consumed by the electronic chip to deduce therefrom the confidential data present in the electronic circuit 110 will not find the variations and therefore cannot implement the attack. Thus protecting the electronic circuit from such attacks.

According to a first aspect, embodiments of an electronic circuit power supply device and method of protecting an electronic circuit against the above-mentioned attacks provide an improvement of the protection against the above-mentioned attacks and/or a faster change of the current I2 supplied to the electronic circuit and/or a reduction of the residual change of the voltage VDD delivered to the circuit compared to the example of the device 100 of fig. 1.

According to a second aspect, embodiments of an electronic circuit power supply device and method of protecting an electronic circuit against the above-mentioned attacks provide easier implementation and/or a reduced number of components compared to the example of the device 100 of fig. 1.

Fig. 2 schematically shows an embodiment of the device 200 for powering electronic circuitry 110 external to the device 200 according to the first aspect. The circuit 110 is of the type described above with respect to fig. 1. The device 200 and the circuitry 110 are preferably comprised within an electronic chip.

In the example shown, the device 200 includes the same or similar elements, arranged the same or similar, as the elements of the device 100 of fig. 1. Such elements and their layout will not be described in detail below. Only the differences are highlighted.

The apparatus 200 differs from the apparatus 100 of fig. 1 in that in the apparatus 200, the component 170 of the apparatus 100 of fig. 1 is replaced by a component 270. As with the component 170 of the device 100 of fig. 1, the component 270 has the function of controlling the transistor T160 to regulate the potential of the node 150 by acting on the current I3 and to consume the current I5 as a mirror of the current I3. In the same manner as the device 100 of fig. 1, the current I5 consumed by the component 270 is added to the current I0 consumed by the electronic circuit 110 and the component 120, so that the total current consumed by the device 200 and the circuit 110 remains constant during the operation of the circuit 110. Thus, the device 200 protects the circuit 110 from attacks.

The assembly 270 of the apparatus 200 differs from the assembly 170 of the apparatus 100 of fig. 1 in that: the component 270 includes a transistor T210 electrically connected in series with a branch of the current mirror 174 defined by a transistor T172; the operational amplifier 178 of the component 170 of fig. 1 is replaced with an operational amplifier 278. The operational amplifier 278 receives the potential difference between the drain terminal 128 and the node 150, and controls the transistor T210; and the conduction terminal of transistor T210 on one side of transistor T175 is coupled (preferably connected) to the gates of transistors T172 and T160 of current mirror 174. In other words, the transistor T210 couples the gates of the transistors T172 and T160 to the node 130, to which the potential VCC is applied. The potential VCC is preferably fixed, that is, constant with respect to the potential GND.

In the example shown, the transistor T210 is of the P-channel MOS type. In this example, the source of transistor T210 is coupled (preferably connected) to node 130, which applies the supply potential VCC. In this example, amplifier 278 has a non-inverting input (+), coupled (preferably connected) to terminal 128, an inverting input (-) coupled (preferably connected) to node 150, and an output coupled (preferably connected) to the gate of transistor T210.

Preferably, the transistor T175 couples the drains of the transistors T210 and T172 together, in other words, the transistor T175 is in series with the transistors T210 and T172 and is located between the transistors T210 and T172.

In operation, the amplifier 278 acts on the gate potential of the transistor T210. This results in an effect on the potential of the coupled-together gates of transistors T172 and T160 of the current mirror 174 due to the fact that transistor T210 couples the gates of transistors T172 and T160 to the node 130, where the potential VCC is applied. This acts on the current I3 to adjust the potential of the node 150 to the value of the potential of the drain terminal 128 of the transistor T127. Transistor T160 is thus controlled to regulate the potential of node 150 by acting on current I3.

In contrast to the device 100 of fig. 1, the output of the amplifier 278 thus controls the gate of the transistor T172 via the transistor T210. As mentioned above, the size of the transistor T172 is generally larger than the size of the transistor T160, in other words, the transistor T160 is smaller than the transistor T172. For example, the size ratio of the transistors T172 and T160 is in the range of approximately 50 to approximately 200, and is preferably equal to 101. In particular, transistor T210 is smaller than transistor T175.

Therefore, the transistor T172 has a relatively high stray gate capacitance compared to the stray gate capacitance of the transistor T210. Due to the fact that the output of the amplifier 278 controls the transistor T172 via the transistor T210, the transistor T172 is controlled faster by the amplifier 278 than by the amplifier 178 of the device 100 of fig. 1.

Thus, the current I5 consumed by the device 200 follows the change in the current I2 consumed by the circuit 110 more quickly than the device 100 of fig. 1.

Due to the fact that the transistor T210 is in series with the transistor T172, the amplifier 278 and the transistor T210 act on the potential of the drain of the transistor T172 to compensate for the difference faster than in a circuit (such as the component 170 of the device of fig. 1) during the time when the variation of the current I2 momentarily results in a difference between the potential of the node 150 and the potential of the drain of the transistor T172. In the illustrated example, if the potential of the node 150 instantaneously increases, the transistor T210 becomes more conductive, which contributes to increasing the drain potential of the transistor T172. In the illustrated example, if the potential of the node 150 is momentarily lowered, the transistor T210 becomes less conductive, which helps to lower the drain potential of the transistor T172. This situation helps to have a faster variation of the current I2 and the current I5 than in a power supply device in which the potentials of the gates of the transistors T160 and T172 are to be controlled via transistors not positioned in series with the transistor T172.

The fact that current I5 follows the change in current I2 more quickly reduces the duration and magnitude of the transient residual change in the current consumed by the chip when current I2 changes value. This case makes it possible to reduce the risk of an attacker instantaneously detecting such residual variations of the current consumed by the chip, for the same speed of change of the value of current I2. Thus improving protection against attacks. This also enables the current I2 consumed by the electronic circuit 110 to change more rapidly for a given level of protection, that is to say a given level of residual variation of the current consumed by the chip. The electronic circuit 110 may thus be faster and/or may provide a more stable voltage VDD to the circuit 110 by increasing the speed of the operational amplifier 122.

Embodiments according to the first aspect are not limited to the specific examples described above. In device 200, component 120 may be replaced with any circuit configured to control transistor T145; and delivers the value of the potential of node 150 for which the current I1' in transistor T145 is a mirror of the current I2 consumed by circuit 110.

Specifically, instead of transistor T145 coupling node 150 to terminal 132, which applies a reference potential, a transistor may be provided that couples node 150 to terminal 130, which applies voltage VCC, as described below with respect to fig. 4. Current I1' flowing through conductor 251 connected to node 150 is replaced with a current flowing through the conductor connected to node 150 towards node 150.

Component 120 and transistor T145 may thus be replaced with any circuit configured to flow current through a conductor connected to node 150 and deliver a value of the potential of node 150 for which the current is a mirror of current I2 consumed by circuit 110.

Fig. 3 schematically shows an embodiment of the power supply device 300 of the electronic circuit 110 external to the device 300 according to the second aspect. The circuit 110 is of the type described above with respect to fig. 1. The apparatus 300 and the circuit 110 are preferably comprised within an electronic chip. The apparatus 300 includes the same or similar elements as those of the apparatus 100 of fig. 1, which elements are not described in detail.

The device 300 comprises a component 320 electrically connected in series with the electronic circuit 110 between the terminal 130 to which the voltage VCC is applied and the terminal 132 to which the reference potential GND is applied. Preferably, the component 320 is located on the side of the terminal 130 to which the potential VCC is applied with respect to the circuit 110. For example, the component 320 is connected to the terminal 130. Further, the component 320 may be coupled (preferably connected) to the terminal 132 to which the reference potential GND is applied. Component 320 delivers voltage VDD to circuit 110 on node 134 defined by the drain terminal of transistor T121.

The component 320 comprises a transistor T121 and an operational amplifier 122, identical or similar to the transistors and operational amplifier of the device 100 of fig. 1, arranged identically or similarly. In the same manner as in the device 100 of fig. 1, the operational amplifier 122 and the transistor T121 regulate the voltage VDD delivered to the circuit 110.

The device 300 includes a node 150 coupled to a terminal 130 that applies a voltage VCC through a transistor T345. The transistor T345 may be of a P-channel MOS type. In particular, transistor T345 has a drain terminal coupled (preferably connected) to node 150 and a source terminal coupled (preferably connected) to terminal 130.

P-channel transistors T121 and T345 form a current mirror 346. The drain terminal 134 of transistor T121 and node 150 form the terminals of the respective branches of current mirror 346. Preferably, the sources of the transistors T121 and T345 are coupled together, more preferably connected together, and the gates of the transistors T121 and T345 are coupled together, more preferably connected together. The branch of the current mirror 346 formed by the transistor T121 is electrically connected in series with the electronic circuit 110 between the terminal 130, to which the reference supply voltage VCC is applied, and the terminal 132, to which the reference potential GND is applied.

In operation, the branch of current mirror 346 formed by transistor T345 causes current I1' to flow to node 150 through conductor 351, which is connected to node 150 and coupled to current mirror 346.

Device 300 also includes a resistive element 355 coupling node 150 to terminal 132 to which a reference potential GND is applied. Resistive element 355 samples current I4 from node 150. In other words, resistive element 355 causes current I4 to flow through conductor 352, which is connected to node 150. The resistive element 355 may be formed by a resistor or a plurality of resistors connected in series and/or in parallel.

The apparatus 300 includes a transistor T360 coupling the node 150 to the terminal 130 at which the voltage VCC is applied. Transistor T360 may be of the P-channel MOS type, the drain of transistor T360 being coupled (preferably connected) to node 150, and the source of transistor T360 being coupled (preferably connected) to terminal 130.

The device 300 also includes a component 370. The component 370 couples the terminal 130 to which the voltage VCC is applied and the terminal 132 to which the reference voltage GND is applied. Component 370 receives the difference between the potentials of the terminals of the branches of current mirror 146 (formed by nodes 150 and 134).

Component 370 includes a transistor T372 that forms a current mirror 374 with transistor T360. The transistor T372 may be of a P-channel MOS type. Transistor T372 may have its source coupled (preferably connected) to terminal 130, which applies voltage VCC. The drain of the transistor T372 may preferably be connected or coupled via a transistor T375 to the terminal 132 to which the reference potential is applied. The transistor T375 is then connected in series with the transistor T372 of the current mirror 374 between the

terminals

130 and 132.

Preferably, the component 370 comprises an operational amplifier 376 controlling the transistor T375 and receiving the difference between the drain potentials of the transistors of the current mirror 374. For example, the transistor is of the N-channel MOS type, and the operational amplifier 376 has an inverting input (-) coupled (preferably connected) to the node 150 and a non-inverting input (+) coupled (preferably connected) to the node 377 connected to each other with the drains of the transistors T372 and T375. Node 377 forms the terminal of the branch of the current mirror 374 defined by transistor T372.

In other words, current mirror 374, transistor T375, and amplifier 376 of device 300 correspond to current mirror 174, transistor T175, and amplifier 176, respectively, of device 100 of fig. 1, where the voltage signs have been swapped, the N-type and P-type of the channels of the transistors have been swapped, and

terminals

130 and 132 have been swapped.

The operation is thus similar to that described in relation to fig. 1. Transistor T360 flows current I3 to node 150 through conductor 353, which is connected to node 150 and coupled to current mirror 374. Amplifier 376 and transistor T375 regulate the potential of terminal 377 to the value of the potential of node 150. The branch of the current mirror 374 formed by the transistor T372 consumes the current I5, which is a mirror image of the current I3, supplied by the terminal 130 to which the potential VCC is applied.

The apparatus 300 also includes an operational amplifier 378. The operational amplifier 378 receives the potential difference between the potential at the node 150 and a constant value VCST. More specifically, operational amplifier 378 has a non-inverting input (+) coupled (preferably connected) to node 150 and an inverting input (-) that receives a potential having a constant value of VCST. The output of operational amplifier 378 is coupled (preferably connected) to the gates of transistors T360 and T372. Thus, the operational amplifier 378 acts on the potentials of the gates of the transistors T360 and T372 of the current mirror 374 that are coupled together.

In operation, operational amplifier 378 adjusts the potential of node 150 to a constant value VCST by acting on current I3.

The current I4 is constant due to the fact that the potential of node 150 is regulated to a constant value. Compared to the device 100 of fig. 1, the constant current I4 has been obtained more simply by replacing the current source 155 by a simple resistive element, the constant current I4 being provided to supply a current that remains constant as the voltage across the current source varies.

According to an embodiment, the constant value VCST is a constant value of the regulated voltage VDD. In the example shown, the non-inverting input of amplifier 378 is coupled (preferably connected) to node 134, which applies voltage VDD. In another example not shown, the non-inverting input of amplifier 378 is coupled or connected to a node having a potential that is the same value as voltage VDD (such as potential VDD0), for example, the non-inverting input of amplifier 122.

Due to the fact that the constant value VCST at which the potential of node 150 is regulated equals the value of voltage VDD, current I1 flowing through conductor 351 by current mirror 346 is a mirror image of current I2 consumed by electronic circuit 110. Thus, current I1 is a mirror image of current I0' supplied by terminal 132, and current I0' is the sum of currents I1' and I2. More specifically, the current I1 'verifies the relationship I1' ═ I0'/(K346+1), where K346 is the ratio between the currents I2 and I1'. In other words, the current I1 verifies the relationship I1 ═ I0'/K', where K ═ K346+ 1. The value K' may be in the range of 50 to 200, e.g. equal to 101.

Current I1', which is a mirror of current I0', has therefore flowed through conductor 351 connected to node 150 without the use of components such as transistors T123, T125, and T127 of device 100 of fig. 1. Thus, the apparatus 300 is easier to form and includes fewer components than an apparatus (such as the apparatus 100 of fig. 1).

Transistors T360 and T372 are provided so that currents I5 and I3 have a ratio equal to the value of constant K346. In other words, the ratio between current I5 and current I3 is the same as the ratio between current I2 and current I1'. Thus, the current I6 supplied by the terminal 130 as the sum of the currents I3 and I5 has a ratio K to the current I3 that is the reciprocal of the ratio 1/K of the current I1 'to the current I0'. Therefore, the sum I0' + I6 of the currents I0 and I6 supplied by the terminal 130 remains constant, equal to K × I4, regardless of the variations of the current I2 consumed by the electronic circuit 110. Thus, the circuit 110 is protected from the attacks described above.

Embodiments according to the second aspect are not limited to the specific examples described above. In device 300, component 370 may be replaced with any circuit configured to control transistor T360 to adjust the potential of node 150 to a constant value VCST; and consumes a current I5 that is a mirror of the current I3 flowing through the transistor T360, that is, an operating current I5 from one of the

terminals

130 and 132 to the other of the

terminals

130 and 132, which is a mirror of the current I3.

Preferably, the circuit replacement component 370 comprises a transistor forming a current mirror with the transistor T360, the transistor T360 forming a branch of the current mirror. The other branch of the current mirror consumes current I5. In this other branch, the potential of the drain terminal is adjusted to a constant value VCST, so that both drain terminals of the current mirror have the same potential. Thus, in a variation, the inverting input of amplifier 376 is not connected or coupled to node 150, but is connected or coupled to another node having a potential equal to or regulated to a constant value VCST, such as node 134 for the supply voltage VDD and the inverting input of amplifier 122.

Further, the component 320 may be replaced with any circuit configured to control the transistor T345 to flow a current I1' that is a mirror of the current I2 through the transistor T345 when the voltage across the transistor T345 has a constant value VCST. Preferably, such a circuit replacement component 320 comprises a transistor forming a current mirror with the transistor T345, the transistor T345 forming a branch of the current mirror. In the other branch of the current mirror, the potential of the drain terminal is adjusted to a constant value VCST, so that both drain terminals of the current mirror have the same potential.

Specifically, instead of the transistor T345 coupling the node 150 to the terminal 130 to which the potential VCC is applied, a transistor, such as the transistor T145 (fig. 1), coupling the node 150 to the terminal 132 to which the reference potential GND is applied may be provided. In the same manner as the transistor T345, the transistor T145 causes a current to flow through a conductor connected to the node 150. Thus, embodiments include the same elements as those of the apparatus 100 of fig. 1, with the difference that: amplifier 178 (fig. 1) receives a constant value VCST at its inverting input; an element capable of regulating the voltage of the drain terminal 128 of the transistor T127 to a constant value VCST is provided in series with the transistors T127 and T125; also, preferably, the current source 155 is formed of a resistive element, which can simplify the current source 155.

Component 320 and transistor T145 can therefore be replaced with any circuit configured to cause current to flow through a given conductor connected to node 150 when the potential of node 150 has a constant value VCST.

Further, resistive element 355 may be replaced with any current source capable of obtaining a constant current I4 when the voltage across the current source has a constant value VCST. In particular, the resistive element 355 does not have to benefit from the above-mentioned advantages of not using components, such as the transistors T123, T125, and T127 (fig. 1).

Fig. 4 schematically shows an embodiment of a device 400 for powering an electronic device 110 combining the first and second aspects. The circuit 110 is of the type described above with respect to fig. 1. The apparatus 400 and the circuit 110 are preferably comprised within an electronic chip.

In the example shown, device 400 includes the same or similar elements, arranged the same or similar, as the elements of device 300 of fig. 3. These elements and their layout will not be described in detail below. Only the differences are highlighted.

Device 400 differs from device 300 of fig. 3 in that in device 400, component 370 of device 300 is replaced by component 470. As with the component 370 of the device 300, the component 470 has the function of controlling the transistor T360 to regulate the potential of the node 150 by acting on the current I3 and to consume the current I5 as a mirror of the current I3. Thus, the apparatus 400 protects the circuit 110 from attacks.

The component 470 of the device 400 differs from the component 370 of the device 300 of fig. 3 in that: component 370 includes a transistor T410 in electrical series with a transistor T372; the operational amplifier 378 of the assembly of fig. 3 is replaced with an operational amplifier 478. The operational amplifier 478 receives the difference between the constant value VCST and the potential of the node 150, and controls the transistor T410; and the conduction terminal 412 of the transistor T410 on one side of the transistor T375 is coupled (preferably connected) to the gates of the transistors T372 and T360 of the current mirror 374.

In the example shown, the transistor T410 is of the N-channel MOS type. In this example, the source of the transistor T410 is coupled (preferably connected) to the terminal 132 to which the reference potential GND is applied. In this example, amplifier 478 has a non-inverting input (+), which is coupled (preferably connected) to terminal 134 or applies a node equal or regulated to a constant value; an inverting input (-) coupled (preferably connected) to node 150; and an output coupled (preferably connected) to the gate of transistor T410. In other words, the transistor T410 couples the gates of the transistors T372 and T360 to the node 132 to which the fixed potential GND is applied.

In operation, the amplifier 478 acts on the gate potential of the transistor T410. This condition causes an effect on current I3 in transistor T360 to regulate the potential of node 150 to a constant value VCST. Transistor T360 is thus controlled to regulate the potential of node 150 by acting on current I3.

In contrast to the apparatus 300 of fig. 3, in the apparatus 400 the output of the amplifier 478 thus controls the gate of the transistor T372 via the transistor T410. The transistor T410 is smaller than the transistor T372. In the same manner as the apparatus 200 of fig. 2, the transistor T372 is controlled faster by the amplifier 478 than the transistor T372 is controlled by the amplifier 378 of the apparatus 300 of fig. 3.

In the same manner as device 200 of fig. 2, in device 400, the current I5 consumed by device 400 follows the change in current I2 consumed by circuit 110 more quickly than in device 300 of fig. 3 due to the fact that the control of transistor T372 is faster and due to the fact that transistor T410 is in series with transistor T372. This provides an improvement in protection from attack and/or a faster change in the current I2 supplied to the electronic circuit and/or a reduction in the residual change in the voltage VDD delivered to the circuit, as compared to the device 300 of fig. 3.

Various embodiments and modifications have been described. Those skilled in the art will appreciate that certain features of these embodiments may be combined, and that other variations will readily occur to those skilled in the art. In particular, although positive voltages VCC and VDD have been described above, one skilled in the art can adapt the embodiments described above (e.g., by swapping the N and P channel conductivity types of the transistors, by swapping the inverting and non-inverting inputs of the operational amplifier, and by inverting the direction of the current flow) to negative voltages VCC and/or VDD.

Further, embodiments have been described in which the transistors are controlled by operational amplifiers. Embodiments implementing the N and P channel conductivity types of one or more transistors being swapped will be within the ability of those skilled in the art to implement inverting and non-inverting inputs of the associated amplifier(s) being swapped, depending on the supply voltage of the amplifier and the nature of the amplifier and transistors.

Finally, the practical implementation of the described embodiments and variants is within the abilities of one skilled in the art based on the functional indications given above.

Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only and is not intended as limiting. The invention is limited only as defined in the following claims and the equivalents thereto.

Claims

1. An apparatus for powering electronic circuitry, the apparatus configured to:

flowing a first current through a first conductor connected to a node, the first current being a mirror of a second current consumed by the electronic circuit;

flowing a third current through a second conductor connected to the node;

adjusting the potential of the node to a constant value by acting on the third current;

flowing a fourth constant current through a third conductor connected to the node; and

consuming a fifth current that is a mirror of the third current.

2. The apparatus of claim 1, wherein a resistive element conducts the fourth constant current.

3. The apparatus of claim 1, wherein the constant value is a value of a regulated potential used to power the electronic circuit.

4. The apparatus of claim 1, wherein:

a first branch of a current mirror coupled to the first conductor conducts the first current; and

the terminal of the second branch of the current mirror has a potential regulated to the constant value.

5. The apparatus of claim 4, wherein the second branch of the current mirror and the electronic circuit are electrically connected in series between a terminal to which a supply voltage referenced to a reference potential is applied and a terminal to which the reference potential is applied.

6. The apparatus of claim 5, wherein the fifth current is supplied by the terminal to which the supply voltage is applied.

7. The apparatus of claim 1, wherein:

a first branch of a current mirror coupled to the second conductor conducts the third current;

a second branch of the current mirror coupled to the second conductor consumes the fifth current; and

the potential of the node is adjusted by acting on the potentials of the gates of the transistors of the current mirror coupled together that are coupled to the second conductor.

8. The apparatus of claim 7, wherein:

a first branch of a second current mirror coupled to the first conductor conducts the first current;

the terminal of the second branch of the second current mirror has a potential adjusted to the constant value; and

the acting on the potential of the gate is performed by an operational amplifier that receives a potential difference between the node and the terminal of the second branch of the second current mirror coupled to the first conductor.

9. The apparatus of claim 7, wherein:

obtaining the effect on the potential of the gate by acting on a control potential of another transistor electrically in series with the second branch of the current mirror coupled to the second conductor; and

the further transistor couples the gate to a further node to which a supply potential is applied.

10. The apparatus of claim 9, wherein the other transistor is smaller than a transistor of the second branch of the current mirror coupled to the second conductor.

11. The apparatus of claim 7, wherein a terminal of the second branch of the current mirror coupled to the second conductor has a potential adjusted to the constant value.

12. The apparatus of claim 11, wherein:

an additional transistor in series with the second branch of the current mirror coupled to the second conductor; and

the additional transistor is controlled by an output of an operational amplifier configured to amplify a difference between the constant value and the potential of the terminal of the second branch of the current mirror coupled to the second conductor.

13. The apparatus of claim 1, wherein a ratio between values of the fifth current and the third current is equal to another ratio between values of the second current and the first current, or to a sum of the another ratio and a unit element.

14. A method of powering an electronic circuit, comprising the steps of:

flowing a third current through a second conductor connected to the node;

consuming a fifth current that is a mirror of the third current.

15. The method of claim 14, further comprising: conducting the fourth constant current through a resistive element.

16. The method of claim 14, wherein the constant value is a value of a regulated potential used to power the electronic circuit.

17. The method of claim 14, further comprising:

conducting the first current by a first branch of a current mirror coupled to the first conductor; and

the potential is regulated to said constant value by a terminal of the second branch of the current mirror.

18. The method of claim 14, further comprising:

conducting the third current by a first branch of a current mirror coupled to the second conductor;

consuming, by a second branch of the current mirror coupled to the second conductor, the fifth current; and

adjusting the potential of the node by an effect on a potential of gates coupled together of transistors of the current mirror coupled to the second conductor.

19. The method of claim 14, wherein a ratio between values of the fifth current and the third current is equal to another ratio between values of the second current and the first current, or to a sum of the another ratio and a unit element.

20. An electronic chip, comprising:

an electronic circuit; and

a device configured to power the electronic circuitry and configured to:

flowing a third current through a second conductor connected to the node;

consuming a fifth current that is a mirror of the third current.