Electronic device

Abstract

Electronic device The present description relates to a circuit for driving a first HEMT power transistor (401) of the e-mode type adapted to receive a maximum voltage of 650 V between its drain and its source, said circuit being formed in and on a monolithic semiconductor substrate having a face covered with a layer of Gallium Nitride, and comprising at least one second transistor (T2205) of the e-mode type adapted to directly transmit a control voltage to the gate of the first transistor (401) and whose area is greater than 5 mm2. Figure for the abstract: Fig. 23

Description

Title of the invention: Electronic device Technical field

[0001] The present description relates generally to electronic systems and devices, and more particularly to electronic systems and devices formed from a Gallium Nitride (GaN) structure. Prior art

[0002] It is conventional to form electronic systems and devices from silicon substrate, but other semiconductor materials can be used. In particular, structures comprising Gallium Nitride (GaN) can be used.

[0003] It would be desirable to be able to improve, at least in part, certain aspects of electronic systems and devices formed from in and on structures comprising Gallium Nitride. Summary of the invention

[0004] There is a need for electronic systems and devices formed in and on structures comprising Gallium Nitride.

[0005] There is a need for electronic systems and devices comprising transistors formed in and on structures comprising Gallium Nitride.

[0006] One embodiment overcomes all or part of the drawbacks of known electronic systems and devices.

[0007] According to a first aspect, an embodiment provides an electronic device formed in and on a monolithic semiconductor substrate having a face covered with a layer of Gallium Nitride, comprising at least one e-mode type HEMT power transistor adapted to receive a maximum voltage of 650 V between its drain and its source, and an analog circuit for controlling said power transistor.

[0008] According to one embodiment, the analog control circuit comprises a circuit for driving said power transistor.

[0009] According to one embodiment, the analog control circuit comprises at least one logic circuit.

[0010] According to one embodiment, the analog control circuit comprises at least one voltage regulator circuit.

[0011] According to one embodiment, the analog control circuit comprises at least one high voltage regulator circuit adapted to receive a maximum voltage of 400 V.

[0012] According to one embodiment, the analog control circuit comprises a overheat protection circuit.

[0013] According to one embodiment, the analog control circuit comprises an overcurrent protection circuit.

[0014] According to one embodiment, the device further comprises input and output connection pads.

[0015] According to one embodiment, at least two levels of metallizations are formed on said layer of Gallium Nitride.

[0016] According to one embodiment, at least three levels of metallizations are formed on said layer of Gallium Nitride.

[0017] Another embodiment provides an integrated circuit comprising a device described above.

[0018] According to one embodiment, the circuit is a power converter.

[0019] According to one embodiment, the circuit is a switching power supply.

[0020] According to a second aspect, an embodiment provides a protection circuit against overheating formed in and on a monolithic semiconductor substrate having one face covered with a layer of Gallium Nitride, comprising: - a first resistor having a first positive temperature coefficient and being arranged in said Gallium Nitride layer; and - a second resistor having a second temperature coefficient different from the first coefficient.

[0021] According to one embodiment, the second resistor is arranged in said substrate, and in which said second coefficient is equal to zero.

[0022] According to one embodiment, the second resistor is arranged in said layer of Gallium Nitride.

[0023] According to one embodiment, said second coefficient is positive.

[0024] According to one embodiment, said second coefficient is negative.

[0025] According to one embodiment, said second resistor is made of a silicon alloy and Chrome.

[0026] According to one embodiment, the circuit further comprises a comparator circuit adapted to compare a first voltage taken at the terminals of the first resistor with a second reference voltage.

[0027] According to one embodiment, the reference voltage is adapted to be provided by a voltage divider bridge.

[0028] According to one embodiment, the impedance of the first resistor is adapted to be adjusted.

[0029] According to one embodiment, the first resistance is formed by a circuit comprising at least one fuse.

[0030] Another embodiment provides an electronic device formed in and on a monolithic semiconductor substrate having one face covered with a layer of Gallium Nitride, comprising an overheating protection circuit described above.

[0031] According to one embodiment, the device further comprises at least one HEMT power transistor of e-mode type adapted to receive a maximum voltage of 650 V between its drain and its source.

[0032] According to one embodiment, said power transistor is formed by at least two assemblies of e-mode type HEMT transistors, and the first resistor is formed between two of said assemblies.

[0033] According to a third aspect, an embodiment provides a circuit for driving a first HEMT power transistor of e-mode type adapted to receive a maximum voltage of 650 V between its drain and its source, said circuit being formed in and on a monolithic semiconductor substrate having a face covered with a layer of Gallium Nitride, and comprising at least one second transistor of e-mode type adapted to directly transmit a control voltage to the gate of the first transistor and whose area is greater than 5 mm2.

[0034] According to one embodiment, said second transistor has an area of ​​between 10 and 15 mm2.

[0035] According to one embodiment, said second transistor is composed of an assembly of several e-mode type transistors.

[0036] Another embodiment provides a device comprising said first power transistor and a driving circuit described previously.

[0037] According to one embodiment, the second transistor of the driving circuit comprises a drain region in direct contact with a gate region of the first power transistor.

[0038] According to a fourth aspect, an embodiment provides a voltage regulator circuit formed in and on a monolithic semiconductor substrate having one face covered with a layer of Gallium Nitride, comprising: - between a first terminal and a second terminal, a first resistor and a first d-mode HEMT transistor; and - between the first terminal and the third terminal, a second HEMT transistor of d-mode type, wherein the midpoint between the first resistor and the first transistor is connected to the gates of the first and second transistors.

[0039] According to one embodiment, the circuit further comprises, between the second terminal and a reference terminal, a Zener diode.

[0040] According to one embodiment, the Zener diode is formed on a portion of the semiconductor substrate which is not covered by the Gallium Nitride layer.

[0041] According to one embodiment, the second terminal or the third terminal are adapted to provide a supply voltage.

[0042] According to one embodiment, the circuit further comprises, between the first resistor and the first transistor, a third HEMT transistor of d-mode type whose gate is connected to the middle node between the first resistor and the third transistor.

[0043] According to one embodiment, the circuit further comprises, between the first terminal and a first node adapted to provide a supply voltage, a fifth HEMT transistor of d-mode type whose gate is connected to the gate of the third transistor.

[0044] According to one embodiment, the circuit further comprises, between the first terminal and a second node adapted to provide a supply voltage, a sixth HEMT transistor of d-mode type whose gate is connected to the gate of the first transistor.

[0045] According to one embodiment, the circuit further comprises, between the first terminal and the second terminal, a seventh HEMT transistor and a second resistor, the drain of the seventh transistor being connected to the first terminal, the source of the seventh transistor being connected to a first terminal of said second resistor, and a second terminal of said second resistor being connected to the second terminal.

[0046] According to one embodiment, the seventh transistor is of d-mode type and has its gate connected to its drain.

[0047] According to one embodiment, the seventh transistor is of the e-mode type, and is adapted to receive a bias voltage on its gate.

[0048] Another embodiment provides a high voltage regulator circuit comprising the voltage regulator circuit described above.

[0049] According to one embodiment, the circuit further comprises the voltage regulator circuit described above.

[0050] According to one embodiment, the circuit comprises: - between a fourth terminal and said first terminal, a first diode, the anode of which is connected to the fourth terminal and the cathode of which is connected to the first terminal; - between a fifth terminal and the first terminal, an eighth d-mode HEMT transistor and a second diode; - between a fifth terminal and a sixth terminal, a third resistor and a flip-flop, the gate of the eighth transistor being connected to the midpoint between said third resistor and said flip-flop.

[0051] According to one embodiment, said eighth transistor is adapted to be controlled by a control circuit comprising: - a ninth HEMT transistor of e-mode type, the drain of which is connected to the gate of the eighth transistor, and the source is connected to the sixth terminal; - a comparator circuit adapted to supply a control voltage to the gate of said ninth transistor, and adapted to compare the voltage of the first terminal to a reference voltage; - a circuit adapted to provide said reference voltage. Brief description of the drawings

[0052] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0053] [Fig.l] represents, very schematically, a structure comprising Gallium Nitride;

[0054] [Fig.2] comprises two views (A) and (B) illustrating a first type of transistor formed in and on a structure comprising Gallium Nitride;

[0055] [Fig.3] represents two views (A) and (B) illustrating a second type of transistor formed in a structure comprising Gallium Nitride;

[0056] [Fig.4] represents, very schematically and in the form of blocks, an embodiment of an electronic device formed in and on a structure comprising Gallium Nitride;

[0057] [Fig.5] represents a schematic top view of a part of the embodiment of [Fig.4];

[0058] [Fig.6] represents a detailed top view of the embodiment of [Fig.4];

[0059] [Fig.7] comprises a view (A) showing an electrical diagram of a first embodiment of a voltage regulator circuit of the embodiment of [Fig.4], and a view (B) showing a sectional view of a structure forming the first embodiment of the voltage regulator circuit;

[0060] [Fig.8] represents an electrical diagram of a second embodiment of a voltage regulator circuit of the embodiment of [Fig.4];

[0061] [Fig.9] represents an electrical diagram of a third embodiment of a voltage regulator circuit of the embodiment of [Fig.4];

[0062] [Fig. 10] represents an electrical diagram of a fourth embodiment of a voltage regulator circuit of the embodiment of [Fig.4];

[0063] [Fig.l 1] represents an electrical diagram of a fifth embodiment of a voltage regulator circuit of the embodiment of [Fig.4];

[0064] [Fig. 12] represents an electrical diagram of a sixth embodiment of a voltage regulator circuit of the embodiment of [Fig.4];

[0065] [Fig. 13] represents an electrical diagram of a seventh embodiment of a voltage regulator circuit of the embodiment of [Fig.4];

[0066] [Fig. 14] represents an electrical diagram of an eighth embodiment of a voltage regulator circuit of the embodiment of [Fig.4];

[0067] [Fig. 15] represents an electrical diagram of a first embodiment of a high voltage regulator circuit of the embodiment of [Fig.4];

[0068] [Fig. 16] represents an electrical diagram of a second embodiment of a high voltage regulator circuit of the embodiment of [Fig.4];

[0069] [Fig. 17] represents an electrical diagram of an exemplary embodiment of a comparator of the embodiment of [Fig. 16];

[0070] [Fig. 18] represents an electrical diagram of a first embodiment of an overheat protection circuit of the embodiment of [Fig.4];

[0071] [Fig. 19] represents an electrical diagram of a second embodiment of an overheat protection circuit of the embodiment of [Fig.4];

[0072] [Fig.20] represents a schematic top view of the embodiment of [Fig.4];

[0073] [Fig.21] comprises two views representing an electrical diagram of a third embodiment of an overheat protection circuit of the embodiment of [Fig.4];

[0074] [Fig.22] is a sectional view showing a fuse of the embodiment of [Fig.21];

[0075] [Fig.23] represents an electrical diagram of a first embodiment of a control circuit of the embodiment of [Fig.4];

[0076] [Fig.24] represents a schematic top view of a portion of the control circuit of [Fig.23];

[0077] [Fig.25] represents an electrical diagram of a second embodiment of a control circuit of the embodiment of [Fig.4];

[0078] [Fig.26] represents an electrical diagram of a third embodiment of a control circuit of the embodiment of [Fig.4];

[0079] [Fig.27] represents an electrical diagram of an embodiment of an overcurrent protection circuit of the embodiment of [Fig.4];

[0080] [Fig.28] includes timing diagrams illustrating the operation of the circuit of [Fig.27];

[0081] [Fig.29] represents a detailed top view of the embodiment of [Fig.4] illustrating the positioning of the control circuit of [Fig.27];

[0082] [Fig.30] shows a schematic sectional view of a first embodiment of a connection terminal of the device of [Fig.4];

[0083] [Fig.31] shows a schematic sectional view of a second embodiment of a connection terminal of the device of [Fig.4];

[0084] [Fig.32] shows a schematic sectional view of a third embodiment of a connection terminal of the device of [Fig.4];

[0085] [Fig.33] represents two views (A) and (B), schematically and partially in block form, an electrical diagram of a first embodiment of an application of the embodiment of [Fig.4] and timing diagrams illustrating the operation of this first embodiment;

[0086] [Fig.34] represents, schematically and partially in block form, an electrical diagram of a second embodiment of an application of the embodiment of [Fig.4];

[0087] [Fig.35] represents timing diagrams illustrating the operation of the embodiment of [Fig.34]; and

[0088] [Fig.36] represents, schematically and partially in block form, an electrical diagram of a third embodiment of an application of the embodiment of [Fig.4]. Description of the embodiments

[0089] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0090] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been represented and are detailed.

[0091] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0092] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made unless otherwise specified to the orientation of the figures.

[0093] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0094] [Fig.l] is a sectional view very schematically representing a semiconducting structure 100 comprising Gallium Nitride.

[0095] The structure 100 is generally composed of a substrate 101 (Si) made of a semiconductor material, for example a silicon substrate, covered on one of its faces with a layer 102 (GaN) made of Gallium Nitride (GaN). The layer 102 has a thickness of between 0.5 and 5 μm.

[0096] When the structure 100 is used as the basis of an electronic system or device, electronic components are formed in and on the layer 102. Metallization levels may further be formed on the layer 102. Examples of metallization levels are described in connection with FIGS. 29-31.

[0097] [Fig.2] comprises two views (A) and (B) illustrating a first type of transistor 200 formed in a structure comprising Gallium Nitride. View (A) represents an electrical diagram of the transistor 200, and view (B) represents a sectional view of a structure 250 forming the transistor 200.

[0098] Transistor 200 is a high electron mobility transistor (HEMT), also called a modulated-doping field effect transistor (MODFET). Hereinafter, a high-mobility elective transistor is called a HEMT transistor.

[0099] A HEMT transistor, like transistor 200, comprises a gate terminal, denoted G in [Fig.2], a source terminal, denoted S in [Fig.2], and a drain terminal, denoted D in [Fig.2],

[0100] In addition, the transistor 200 is a depletion mode HEMT transistor, hereinafter referred to as a d-mode HEMT transistor, or d-mode transistor. Alternatively, the transistor 200 is a normally-ON HEMT transistor, or normally ON HEMT transistor, or normally ON transistor. The electrical diagram of the transistor 200 shown in view (A) is the electrical diagram that will be used in all subsequent figures to represent a d-mode or normally ON transistor.

[0101] In practice, the transistor 200 can be obtained by a structure 250 formed from a structure of the type of the structure 100 described in relation to [Fig.l]. Thus, the structure 250 comprises a substrate 251 (Si) made of a conductive material, such as silicon, one face of which is covered by a layer 252 (GaN) of Gallium Nitride. The layer 252 of Gallium Nitride is partially covered by a layer 253 (AlGaN) of Aluminum-Gallium Nitride. A connection terminal 254 forms the source contact S of the transistor 200. The connection terminal 254 is formed on a portion of the layer 252 which is not covered by the layer 253. A connection terminal 255 forms the drain contact D of the transistor 200. The connection terminal 255 is formed on a portion of the layer 252 which is not covered by the layer 253. A connection terminal 256 forms the gate contact G of the transistor 200.The connection terminal 256 is formed on a portion of the layer 253, and is disposed between the connection pads 254 and 255.

[0102] The operation of transistor 200 is as follows. When the gate G of transistor 200 is left floating or a positive voltage is applied between its gate G and its source S, transistor 200 is conductive, hence its name transistor normally ON. To "close" transistor 200, i.e. to make it non-conductive, a negative voltage must be applied between its gate G and its source S.

[0103] [Fig.3] includes two views (A) and (B) illustrating a second type of transistor 300 formed in a structure comprising Gallium Nitride. View (A) represents an electrical diagram of the transistor 300, and view (B) represents a sectional view of a structure 350 forming the transistor 300.

[0104] Like the transistor 200 described in relation to [Fig.2], the transistor 300 is a high electron mobility transistor, or HEMT. The transistor 300 comprises a gate terminal, denoted G in [Fig.3], a source terminal, denoted S in [Fig.3], and a drain terminal, denoted D in [Fig.3].

[0105] In addition, and unlike transistor 200 of [Fig.2], transistor 300 is an enhancement mode HEMT transistor, hereinafter referred to as an e-mode HEMT transistor, or e-mode transistor. Alternatively, transistor 300 is a normally-OFF HEMT transistor, or normally OFF HEMT transistor, or normally OFF transistor. The electrical diagram of transistor 300 shown in view (A) is the electrical diagram that will be used in all subsequent figures to represent an e-mode or normally OFF transistor.

[0106] In practice, the transistor 300 can be obtained by a structure 350 formed from a structure of the type of the structure 100 described in relation to [Fig.l]. Thus, the structure 350 comprises a substrate 351 (Si) made of a conductive material, such as silicon, one face of which is covered by a layer 352 (GaN) of Gallium Nitride. The layer 352 of Gallium Nitride is partially covered by a layer 353 (AlGaN) of Aluminum-Gallium Nitride. A connection terminal 354 forms the source contact S of the transistor 300. The connection terminal 354 is formed on a portion of the layer 352 which is not covered by the layer 353. A connection terminal 355 forms the drain contact D of the transistor 300. The connection terminal 355 is formed on a portion of the layer 352 which is not covered by the layer 353. A connection terminal 356 forms the gate contact G of the transistor 300.The connection terminal 356 is formed between the layer 352 and the layer 353 and is disposed between the connection pads 354 and 355. In addition, a portion of the connection pad 354 covers the portion of the layer 353 covering the connection pad 356 as shown in view (B) of [Fig.3].

[0107] The operation of transistor 300 is as follows. When the gate G of transistor 300 is left floating or a negative voltage is applied between its gate G and its source S, transistor 300 is not conducting or non-conducting, hence its name of normally OFF transistor. To "open" transistor 300, that is to say to make it conductive, a positive voltage must be applied between its gate G and its source S.

[0108] [Fig.4] represents, very schematically and in the form of blocks, a mode of rea lization of an electronic device 400 formed in and on a structure of the type of the structure described in relation to [Fig.l].

[0109] According to one embodiment, the device 400 is formed entirely in and on a structure of the type of the structure 100 described in relation to [Fig.l], that is to say a structure comprising Gallium Nitride (GaN), and more particularly, a structure composed of a semiconductor substrate having one face covered with a layer of Gallium Nitride. In other words, the device 400 is formed entirely in and on a monolithic structure of the type of the structure 100 described in relation to [Fig.l].

[0110] According to one embodiment, the device 400 is an electronic device adapted to support high voltages, i.e. voltages of up to 650 V. For this, the device 400 comprises a power transistor 401 and an analog control circuit 450 for the power transistor 401.

[0111] The power transistor 401 is an emission-mode HEMT transistor, or e-mode transistor, or normally OFF transistor comprising a drain terminal 401D, two source terminals 401S1 and 401S2, and a gate terminal 401G. The source terminal 401S1 is, in practice, arranged between the source terminal 401S2 and the gate terminal 401G of the transistor 401. The power transistor 401 is dimensioned to withstand a maximum voltage of the order of 650 V at its drain terminal 401D and its source terminal 401S1 or 401S2.

[0112] In practice, the power transistor 401 is an assembly of several e-mode transistors in parallel. An example of an assembly that can form the transistor 401 is described in relation to [Fig.5].

[0113] The analog control circuit 450 is adapted to control the power transistor 401. The circuit 450 comprises: - a driver circuit 451 (DRIVER) for transistor 401; - 452 logic circuits (LOGIC); - 453 voltage regulator circuits (REG); - a 454 overheat protection circuit (OT Prot); - a 455 overcurrent protection circuit (OC Prot); - a 456 resistor; and - one or more electrostatic discharge (ESD) protection circuits 457.

[0114] The device 400 further comprises input and output connection terminals, or input and output connection pads, represented in [Fig.4] by blocks arranged on the line delimiting the block forming the device 400. The input and output connection terminals comprise: - a drain terminal 470 (DRAIN) of the power transistor 401 connected, preferably connected, at terminal 401D; - a source terminal 471 (SOURCE) of the power transistor 401 connected, preferably connected, to the terminal 401S2; - a reference terminal 472 (SGND); - a terminal 473 (DIAG_OC) for overcurrent testing; — a terminal 474 (DIAG_OT) for overheating testing; - a 475 (IN) input control terminal; - a supply terminal 476 (VDD) delivering a supply voltage to the control circuit 451; - a terminal 477 (DZ) for controlling and supplying a supply voltage; and - a supply terminal 478 (VCC) delivering a supply voltage for the device 400.

[0115] Practical embodiments of connection terminals are described in connection with Figures 29 to 31.

[0116] The driver circuit 451 (DRIVER) of the transistor 401 comprises a power supply terminal 451SUPP, a reference power supply terminal 451GND, a control terminal 451CMD, or input terminal 451CMD, and an output terminal 451OUT. The reference terminal 451GND is connected, preferably connected to the source terminal 401S1 of the power transistor 401 and to the source terminal 471 of the device 400. The output terminal 451OUT is connected, preferably connected to the gate terminal 401G of the power transistor 401. Detailed examples of driver circuits 451 are described in relation to FIGS. 22 to 24.

[0117] The logic circuits 452 (LOGIC) make it possible to manage all the control logic of the control circuit 451; these circuits are within the reach of a person skilled in the art. According to one example, the logic circuits implement a "NAND" type logic gate. The logic circuits 452 comprise: - a 452SUPP power supply terminal; - a 452IN input terminal; - an output terminal 452OUT connected, preferably connected, to the control terminal 451CMD of the control circuit 451; - a 452OT overheating test terminal; and - a 452OC overcurrent test terminal.

[0118] The logic circuits 452 may be part of the control circuit 451.

[0119] The voltage regulator circuits 453 (REG) are circuits providing, from a supply voltage coming from the terminal 478, a supply voltage adapted to supply the control circuit 451, the logic circuits 452 and the test circuits 454 and 455. The circuits comprise an input terminal 453, a control terminal 453CMD, and at least two output supply terminals 453OUT1 and 453OUT2. The input terminal 453IN is connected, preferably connected, to the power supply terminal 478 of the device 400. The control terminal 453CMD is connected, preferably connected, to the control terminal 477 of the device 400. The input terminal 453OUT1 provides, for example, a supply voltage to the circuits 452, 454 and 455, and is, among other things, connected, preferably connected, to the terminal 452SUPP of the logic circuits 452. The input terminal 453OUT2 provides, for example, a supply voltage to the driver circuit 451, and is connected, preferably connected, to the terminal 451SUPP of the driver circuit 451, and to the power supply terminal 476 of the device 400. Detailed examples of voltage regulator circuits 453 are described in relation to FIGS. 7 to 17.

[0120] The overheating protection circuit 454 (OT Prot) makes it possible to detect an abnormal increase in temperature, for example an exceeding of a threshold temperature, for example of the order of 175 °C, which could damage the device 400. The circuit 454 comprises a power supply terminal 454SUPP and an output terminal 454OUT. The power supply terminal 454SUPP is connected, preferably connected, to the output terminal 453OUT1 of the circuits 453. The output terminal 454OUT is connected, preferably connected, to the test terminal 474 of the device 400 and to the test terminal 452OT of the logic circuits 452. Detailed examples of overheating protection circuits 454 are described in relation to FIGS. 18 to 21.

[0121] The overcurrent protection circuit 455 (OC Prot), or current spike protection circuit, is used to detect an abnormal increase in current that could damage the device 400. The circuit 455 includes a power supply terminal 455SUPP, a test terminal 455LOGIC of the logic circuits, and a test terminal 455T of the power transistor 401. The power supply terminal 455SUPP is connected, preferably connected, to the output terminal 453OUT1 of the circuits 453. The test terminal 454LOGIC is connected, preferably connected, to the test terminal 473 of the device 400 and to the test terminal 452OC of the logic circuits 452. The test terminal 455T is connected, preferably connected, to the source terminal 401S2 of the power transistor 401. Detailed examples of overcurrent protection circuits overcurrents 454 are described in relation to figures 26 to 28.

[0122] The resistor 456 is arranged between the source terminals 401S1 and 401S2 of the power transistor 401. More particularly, a first terminal of the resistor 456 is connected, preferably connected, to the source terminal 401S1, and a second terminal of the resistor 456 is connected, preferably connected, to the source terminal 401S2 and to the test terminal 455T of the circuit 455. The resistor 456 is a shunt resistor making it possible to read the voltage between the drain and the source of the transistor 401 when the latter is conducting or passing.

[0123] The one or more electrostatic discharge (ESD) protection circuits 457 allow all or part of the input and output connection terminals 470 to 478 of the device 400 to be protected. In [Fig.4], terminals 473 to 478 are each protected by a circuit 457. More particularly, six circuits 457 are placed, respectively, between terminals 478 and 453IN, terminals 477 and 453CMD, terminals 476 and 453OUT2, terminals 475 and 452IN, terminals 474 and 454OUT, and terminals 473 and 455LOGIC.

[0124] The devices 400 may be used in several types of electronic systems, for example integrated circuits, such as switching power supplies, boost converters. A top view of an exemplary embodiment of the device 400 is described in relation to [Fig. 6]. Detailed examples of application of the device 400 are described in relation to FIGS. 32 to 34.

[0125] [Fig.5] is a schematic top view of one or part of an assembly 500 for forming a power transistor of the type of transistor 401 described in relation to [Fig.4].

[0126] The assembly 500 is formed by several e-mode or normally OFF transistors arranged in parallel and having a common drain region 501, a common source region 502 and a common gate region 503. For this, the regions 501, 502 and 503 each have a comb shape and are nested inside each other as illustrated in [Fig.5].

[0127] The drain region 501 is connected, preferably connected, to a drain node 500D. The source region 502 is connected, preferably connected, to a source node 500S. The gate region 503 is connected, preferably connected, to a gate node 500G.

[0128] Only a portion of an assembly 500 is shown in [Fig.5]. The regions 501 to 503 may each comprise up to 28 "teeth", i.e. horizontal portions in [Fig.5]. To form the transistor 401 of [Fig.1] several assemblies 500 may be linked, or even connected, to each other.

[0129] [Fig. 6] is a top view of a practical embodiment of the device 400 described in relation to [Fig. 4]. As previously described, the device 400 is formed in and on a structure comprising Gallium Nitride.

[0130] In [Fig. 6], the transistor 401 is formed by at least four assemblies of the type of the assembly 500 described in relation to [Fig. 5]. The assemblies are separated vertically by regions which may comprise, certain examples are described in relation to FIGS. 20 and 28, circuits of the analog control circuit 450. The remainder of the analog control circuit 450 is formed against the transistor 401. The input / output connection terminals 470 to 478 (referenced 470 to 478 in [Fig. 6]) are formed at the periphery of the structure in and on which the device 400 is formed.

[0131] Figures 7 to 17 schematically represent, and partially in block form, examples of embodiments of voltage regulator circuits capable of part of the voltage regulator circuits 453 described in connection with [Fig.4].

[0132] [Fig.7] comprises two views (A) and (B). View (A) represents a first embodiment of a voltage regulator circuit 700, adapted to be part of the device 400 described in relation to [Fig.4]. View (B) is a sectional view of a structure forming part of the circuit 700.

[0133] The voltage regulator circuit 700 is adapted to be connected to three connection terminals of the device 400, and more particularly: - to a VCC terminal corresponding to the connection terminal 478 of the device 400; - to a DZ terminal corresponding to the connection terminal 477 of the device 400; and - to a VDD terminal corresponding to the connection terminal 476 of the device 400.

[0134] The circuit 700 comprises between the VCC terminal and the DZ terminal a resistor R701 and an e-mode type transistor T701. More particularly, a first terminal of the resistor R701 is connected, preferably connected, to the VCC terminal, and a second terminal of the resistor R701 is connected, preferably connected, to the drain of the transistor T701. The source of the transistor T701 is connected, preferably connected, to the DZ terminal. In addition, the gate of the transistor T701 is connected, preferably connected, to the drain of the transistor T701. The resistor R701 is a bias resistor, formed in a two-dimensional structure (2DEGAN) comprising Gallium Nitride, and having a positive temperature coefficient.

[0135] The circuit 700 further comprises an e-mode type transistor T702 arranged between the terminals VCC and VDD. More particularly, the drain of the transistor T702 is connected, preferably connected, to the terminal T702, and the source of the transistor T702 is connected, preferably connected, to the terminal VDD. In addition, the gate of the transistor T702 is connected, preferably connected, to the gate of the transistor T701. The transistor T701 makes it possible to compensate the threshold voltage Vth(T702) of the transistor T702. The current I(T701) flowing through the transistor T701 is given by the following mathematical formula: [Math 1] / (7701) = which - V(VCC) represents the voltage at terminal VCC; - V(DZ) represents the voltage at terminal DZ; - Vth(T701) is the threshold voltage of transistor T701; and - R701 corresponds to the resistance of resistor R701.

[0136] The circuit 700 further comprises a Zener diode D701 between the terminal DZ and a reference node GND, receiving for example the ground. The cathode of the diode D701 is connected, preferably connected, to the terminal DZ, and its anode is connected, preferably connected, to the node GND. The Zener diode is external to the device 400, or is formed on a portion of the structure 100 of [Fig.l] in which the substrate is not re- covered with the Gallium Nitride layer.

[0137] The circuit 700 further comprises, optionally, a capacitor C701 having a buffer capacitor function. The capacitor C701 is disposed between the terminal VDD and the reference node GND. A first terminal of the capacitor C701 is connected, preferably connected, to the terminal VDD, and a second terminal of the capacitor C701 is connected, preferably connected, to the node GND. According to one example, the capacitor C701 is external to the device 400, or is formed on a portion of the structure 100 of [Fig.l] in which the substrate is not covered with the Gallium Nitride layer.

[0138] According to one embodiment, the resistor R701 may be formed directly in the Gallium Nitride layer of the structure of the device 400, and may comprise a positive temperature coefficient. According to a variant, the resistor R701 may be a resistor made of a Silicon and Chromium (SiCr) alloy. In view (B) of [Fig.7], the placement of the resistor R701 is shown. More particularly, in view (B), a sectional view of a structure 750 of the type of the structure 100 described in relation to [Fig.1] is shown. The structure 750 comprises, successively: - a semiconductor substrate 751 (Si), for example made of silicon; - a layer of Gallium Nitride 752 (GAN); and - levels of metallization 753.

[0139] In the last metallization level 754 of the levels 753, i.e. the level furthest from the Gallium Nitride layer 752, the structure 750 comprises metallizations from which the resistor R701 can be formed.

[0140] The circuit 700 makes it possible to supply a current at the terminal DZ, and to create a voltage at the terminals of the Zener diode D701. This voltage is independent of the voltage supplied at the terminal VCC and can be used to power one or more circuits of the control circuit 450 of the device 400 via the terminal VDD. In addition, this voltage can serve as a stable reference voltage making it possible to create the supply voltage supplied at the terminal VDD.

[0141] [Fig.8] represents a second embodiment of a voltage regulator circuit 800, adapted to form part of the device 400 described in relation to [Fig.4].

[0142] Circuit 800 has elements in common with circuit 700 of [Fig.7]. These elements will not be described again and only the differences between circuits 700 and 800 will be highlighted.

[0143] Circuit 800 includes the same terminals as circuit 700 and all components of circuit 700, but additionally includes two e-mode type transistors T801 and T802.

[0144] Transistor T801 is placed between resistor R701 and transistor T701. The drain of transistor T801 is connected, preferably connected, to the terminal of resistor R801 which is not connected to the VCC terminal, and the source of transistor T801 is connected, preferably connected, to the drain of transistor T701. In addition, the gate of transistor T801 is connected, preferably connected, to the drain of transistor T801. Transistor T801 is a voltage follower transistor.

[0145] Transistor T802 is placed between terminal VCC and an output node OUT800 of circuit 800. The drain of transistor T802 is connected, preferably connected, to terminal VCC, and the source of transistor T801 is connected, preferably connected, to node OUT800. In addition, the gate of transistor T802 is connected, preferably connected, to the gate of transistor T801.

[0146] The current I(DZ) supplied at terminal DZ is given by the following mathematical formula: [Math 2] K H7 \ — v( which Vth(T801) is the voltage threshold of transistor T801.

[0147] The voltage V(VDD) supplied at terminal VDD is given by the following mathematical formula: [Math 3] V(VDD) = V(DZ) + Vth(T701 ) + m(T702)in which Vth(T702) is the threshold voltage of transistor T702.

[0148] Like circuit 700, circuit 800 provides a supply voltage on terminal VDD, but circuit 800 can additionally provide at node OUT800 a second supply voltage independent of the voltage received at node VCC and of the voltage provided at node VDD. If a second supply voltage is not required, transistor T802 can be omitted. The advantage of providing several independent supply voltages is to make it possible to isolate a power supply on which noise may appear from a more sensitive power supply.

[0149] [Fig.9] represents a third embodiment of a voltage regulator circuit 900, adapted to form part of the device 400 described in relation to [Fig.4].

[0150] Circuit 900 has elements in common with circuit 700 of [Fig.7] and circuit 800 of [Fig.8]. These elements will not be described again and only the differences between circuits 700, 800 and 900 will be highlighted.

[0151] The circuit 900 comprises the same terminals as the circuit 700 and all the components of the circuit 700, but may optionally comprise the transistor T801 of the circuit 800. The circuit further comprises at least one transistor T901, and for example, a transistor T902 making it possible to provide several supply voltages in parallel.

[0152] Transistor T901 is placed between terminal VCC and an output node T901. The drain of transistor T901 is connected, preferably connected, to terminal VCC, and the source of the transistor T901 is connected, preferably connected, to the node OUT901. In addition, the gate of transistor T901 is connected, preferably connected, to the gate of transistor T701.

[0153] Transistor T902 is placed between terminal VCC and an output node T902. The drain of transistor T902 is connected, preferably connected, to terminal VCC, and the source of transistor T902 is connected, preferably connected, to node OUT902. In addition, the gate of transistor T902 is connected, preferably connected, to the gate of transistor T701.

[0154] The nodes OUT901 and OUT902 and the terminal VDD each provide a supply voltage. These supply voltages can be used to power different circuits of the control circuit 450 of the device 400. In particular, in [Fig.9], three circuits 951 (CIRC 1), 952 (CIRC 2) and 953 (CIRC 3) which can be part of the circuit 450 are shown and are powered by the supply voltage provided by the node OUT901. In addition, the circuit 953 is, furthermore, powered by the voltage provided by the terminal VDD. According to one example, the circuits 951, 952 and 953 can be chosen from the group comprising: the protection circuits 473, 474 and 453, the logic circuits 452 and the control circuit 451. As stated previously, the advantage of providing several independent supply voltages is to make it possible to isolate a power supply on which noise may appear from a more sensitive power supply.

[0155] According to a variant, the circuit 900 could comprise other transistors arranged in a similar manner to the transistors T901 and T902 to provide other supply voltages on other output nodes of the circuit 900.

[0156] [Fig. 10] represents a fourth embodiment of a voltage regulator circuit 1000, adapted to form part of the device 400 described in relation to [Fig.4].

[0157] Circuit 1000 has elements in common with circuit 700 of [Fig.7], circuit 800 of [Fig.8], and circuit 900 of [Fig.9]. These elements will not be described again and only the differences between circuits 700, 800, 900 and 1000 will be highlighted.

[0158] Circuit 1000 is similar to circuit 900 but does not include transistor T902 and output node OUT902.

[0159] The important difference between circuit 1000 and circuit 900 is that the voltage at terminal DZ is used to power circuits 951, 952 and 953.

[0160] Furthermore, an advantage of this embodiment is that the power supply provided at terminal DZ is more precise than that provided by transistors T702, T901 and T902.

[0161] [Fig. 11] represents a fifth embodiment of a voltage regulator circuit 1100, adapted to form part of the device 400 described in relation to [Fig.4].

[0162] The voltage regulator circuit 1100 is adapted to be connected to three connection terminals of the device 400, and more particularly: - to terminal VCC corresponding to connection terminal 478 of device 400; - to terminal DZ corresponding to connection terminal 477 of device 400; and - to terminal VDD corresponding to connection terminal 476 of device 400.

[0163] The voltage regulator circuit 1100 comprises a voltage regulator circuit, and more particularly, in [Fig. 11], the voltage regulator circuit 700 (VOLT GEN) described in relation to [Fig.7]. According to a variant, the voltage regulator circuit could be the circuit 800 described in relation to [Fig.8], the circuit 900 described in relation to [Fig.9], or the circuit 1000 described in relation to [Fig.10].

[0164] The circuit 1100 further comprises a d-mode type transistor Tl 101 and a resistor RI 101. The transistor Tl 101 and the resistor RI 101 are arranged between the terminals VCC and DZ. More particularly, the drain of the transistor Tl 101 is connected, preferably connected, to the terminal VCC, and the source of the transistor Tl 101 is connected, preferably connected, to a first terminal of the resistor RI 101. The gate of the transistor Tl 101 is connected, preferably connected to the terminal DZ. The second terminal of the resistor RI 101 is connected, preferably connected, to the terminal DZ.

[0165] The resistor RI 101 is of the same type as the resistor R701 of the circuit 700 in [Fig.7],

[0166] The output current of the circuit 100 is delivered at the terminal DZ and is proportional to the voltage between the gate of the transistor Tl 101 and the resistor RI 101. The output current I(DZ) is given by the following mathematical formula: [Math 4] 1 (D7 i — 101) in which: - Æ1]01 - Vth(Tl 101) is the threshold voltage of transistor Tl 101; and - RI 101 is the resistance of resistor RI 101.

[0167] Furthermore, the voltage regulator 1100 described in relation to [Fig. 11] differs from the voltage regulators 700 to 1000 described in relation to FIGS. 7 to 10 in that it makes it possible to provide an output voltage at the node VDD, but also an output current at the terminal DZ. This output current has the particularity of not depending on the voltage and current variations that may occur at the terminal VCC, unlike a current provided at the terminal DZ by one of the voltage regulators 700 to 1000 which is dependent on the voltage VCC.

[0168] [Fig. 12] represents a sixth embodiment of a voltage regulator circuit 1200, adapted to form part of the device 400 described in relation to [Fig.4].

[0169] Circuit 1200 has elements in common with circuit 1100 of [Fig. 11]. These elements will not be described again and only the differences between circuits 1100 and 1200 will be highlighted.

[0170] Circuit 1200 includes the same terminals as circuit 1100, resistor RI 101 and circuit 700 (VOLT GEN), but includes, instead of transistor T1 101, a transistor T1201.

[0171] Transistor T1201 is an e-mode, or normally OFF, transistor. The drain of the transistor T1201 is connected, preferably connected, to the terminal VCC, and the source of the transistor T1201 is connected, preferably connected, to a first terminal of the resistor RI 101. The second terminal of the resistor RI 101 is connected, preferably connected, to the terminal DZ. The gate of the transistor T1201 is connected, preferably connected, to an input node IN 1200 receives a bias voltage VBIAS making it possible to turn on the transistor T1201. According to an alternative embodiment, the transistor T1201 is a d-mode type transistor.

[0172] Like circuit 1100, circuit 1200 provides on node DZ an output current proportional to the resistance of resistor RI 101, and independent of the current and voltage variations present at terminal VCC.

[0173] The advantage of this embodiment is to choose a transistor T1201 sized for higher voltages, for example voltages between 10 and 30 V. This therefore makes it possible to apply a voltage between 10 and 30 V to the VCC terminal.

[0174] [Fig. 13] represents a seventh embodiment of a voltage regulator circuit 1300, adapted to form part of the device 400 described in relation to [Fig.4].

[0175] Circuit 1300 has elements in common with circuit 1100 of [Fig. 11] and with circuit 1200 of [Fig. 11]. These elements will not be described again and only the differences between circuits 1100, 1200, and 1300 will be highlighted.

[0176] Circuit 1300 is a combination of circuits 1100 and 1200. In practice, circuit 1300 comprises transistors T1 101 and T1201 and resistor RI 101 and circuit 700.

[0177] More particularly, the transistor T1201 is positioned on the side of the VCC terminal and the transistor T1 101 is positioned on the side of the resistor RI 101. According to one example, in this configuration, the transistor T1201 has the function of isolating the voltage received by the VCC terminal from the drain of the transistor T1 101.

[0178] A preferred embodiment is circuit 1300 comprising voltage regulator circuit 1000.

[0179] Like circuits 1100 and 1200, circuit 1300 has the advantage of providing an output current independent of the current and voltage variations present at terminal VCC.

[0180] [Fig. 14] shows an eighth embodiment of a voltage regulator circuit 1400, adapted to form part of the device 400 described in relation to [Fig.4].

[0181] Circuit 1400 has elements in common with circuits 1100, 1200 and 1300 of FIGS. 11 to 13. These elements will not be described again and only the differences between circuits 1100, 1200, 1300 and 1400 will be highlighted.

[0182] Circuit 1400 includes all the components of circuit 1300 but further includes a new branch between terminals VCC and DC for applying voltage VBIAS to the gate of transistor T1201.

[0183] This new branch comprises a resistor R1401 and several e-mode type transistors T1401 arranged in series. In [Fig.14], the circuit 1400 comprises three transistors T1401. A first terminal of the resistor R1401 is connected, preferably connected, to the terminal VCC, and the second terminal of the resistor R1401 is connected, preferably connected, to the gate of the transistor T1201 and to the drain of a first transistor T1401. The source of the first transistor T1401 is connected, preferably connected, to the drain of the next transistor T1401, and so on. The source of the last transistor T1401 is connected, preferably connected, to the terminal DZ. In addition, each transistor T1401 has its gate connected, preferably connected, to its drain, and is thus connected as a "diode".

[0184] Resistor R1401 and transistors T1401 are sized to provide the VBIAS voltage at the gate of transistor T1201. In addition, resistor R1401 is a bias resistor, which limits the current flowing through transistor T1401. The VBIAS voltage is given by the following mathematical formula: [Math 5] VBIAS = 3*Vth(T1401) in which Vth(T1401) is the threshold voltage of one of the transistors T1401.

[0185] The current I(R1401) flowing through resistor R1401 is given by the following mathematical formula: [Math 6] V( vcc)-3^vth( ri 401)-V(PZ) in which R1401 is the resistance of wire 041 resistor R1401.

[0186] Like circuits 1100, 1200 and 1300, circuit 1400 has the advantage of providing an output current independent of the current and voltage variations present at terminal VCC.

[0187] [Fig. 15] represents a first embodiment of a high voltage regulation circuit 1500, or high voltage regulator circuit 1500, adapted to form part of the device 400 described in relation to [Fig.4].

[0188] The high voltage regulation circuit 1500 is adapted to be connected to five connection terminals of the device 400, and more particularly: - to the VCC terminal corresponding to the connection terminal 478 of the device 400; - to terminal DZ corresponding to connection terminal 477 of device 400; - to the VDD terminal corresponding to the connection terminal 476 of the device 400; - to an internal SUPPLY terminal of the device 400 adapted to receive a voltage maximum of the order of 400 V; and - to an SGND terminal corresponding to the reference connection terminal 472 of the device 400.

[0189] The high voltage regulation circuit 1500 is a circuit adapted to receive a maximum voltage of the order of 400 V on the SUPPLY terminal, and to supply a voltage on the VDD terminal lower than the voltage supplied to the DZ terminal.

[0190] The regulation circuit 1500 comprises a circuit 1550 (GEN) which may be a voltage regulator circuit such as one of the circuits described in relation to FIGS. 7 to 10 or their variants, or which may be a voltage regulator circuit such as one of the circuits described in relation to FIGS. 11 to 14 or their variants. As described in relation to FIGS. 7 to 14, the circuit 1550 is adapted to be connected, preferably connected, to three terminals of the device 400, in particular the terminals VCC, DZ and VDD. The circuit 1550 then comprises a terminal VCC1550 normally connected to the terminal VCC, a terminal DZ1550 normally connected to the terminal DZ, and a terminal VDD1550 normally connected to the terminal VDD. In circuit 1500, terminal VCC1550 is connected, preferably connected, to node IN1500, terminal DZ1550 is connected, preferably connected, to terminal DZ, and terminal VDD1550 is connected, preferably connected, to terminal VDD.

[0191] The circuit 1500 further comprises, between the terminal VCC and the node IN1500, a diode DI501 of the HEMT type, or high electron mobility diode. The anode of the diode D1501 is connected, preferably connected, to the terminal VCC, and the cathode of the diode DI501 is connected, preferably connected, to the node IN 1500.

[0192] The circuit 1500 further comprises, between the SUPPLY terminal and the IN1500 node, an e-mode type transistor T1501 and a diode DI502. The drain of the transistor T1501 is connected, preferably connected, to the SUPPLY terminal, and the source of the transistor T1501 is connected, preferably connected, to the anode of the diode DI502. The cathode of the diode DI502 is connected, preferably connected, to the IN1500 node.

[0193] The circuit 1500 further comprises, between the SUPPLY terminal and the SGND terminal, a resistor R1501 and a flip-flop C1501 (CLAMP). A first terminal of the resistor R1501 is connected, preferably connected, to the SUPPLY terminal, and a second terminal of the resistor R1501 is connected, preferably connected, to a first terminal of the flip-flop C1501. The second terminal of the flip-flop C1510 is connected, preferably connected, to the SGND terminal.

[0194] The operation of circuit 1500 is as follows. When the voltage between the gate and the source of transistor T1501 is greater than the threshold voltage of transistor T1501 then transistor T1501 is conductive, and node IN1500 then receives the voltage coming from the SUPPLY terminal, because transistor T1501 is a voltage follower transistor. Conversely, when the voltage between the gate and the source of transistor T1501 is lower than the threshold voltage of transistor T1501 then transistor T1501 no longer conducts, and node IN1500 then receives the current from terminal VCC.

[0195] Thus, when the voltage delivered by the VCC terminal exceeds the difference between the voltage across the flip-flop Cl501 and the threshold voltage of the transistor T1501, then the power supply of the circuit 1550 is modified to come from the VCC terminal and no longer from the SUPPLY terminal. This makes it possible to avoid excessive energy consumption from the SUPPLY terminal. The flip-flop Cl501 is sized so that the transistor T1501 remains on until the voltage at the SUPPLY terminal exceeds the threshold voltage. The SUPPLY terminal still provides a current of the order of 40 pA, corresponding to the current flowing through the resistor R1501.

[0196] This embodiment is used in the embodiment described in relation to [Fig.36],

[0197] [Fig. 16] shows a second embodiment of a high voltage regulation circuit 1600, or high voltage regulator circuit 1600, adapted to form part of the device 400 described in relation to [Fig.4].

[0198] The circuit 1600 has elements in common with the circuit 1500 of [Fig. 15]. These elements will not be described again and only the differences between the circuits 1500 and 1600 will be highlighted.

[0199] The circuit 1600 comprises all the components of the circuit 1500 but further comprises a control circuit for the transistor T1501, arranged between the gate of the transistor T1501 and the terminal SGND.

[0200] The control circuit comprises an e-mode type transistor T1601, a comparator Cl601 and a voltage source G1601. The drain of the transistor T1601 is connected, preferably connected, to the gate of the transistor T1501, and the source of the transistor T1501 is connected, preferably connected, to the terminal SGND. The gate of the transistor Cl601 receives an output voltage from the comparator Cl601. The comparator receives, as input, the voltage from the terminal VCC and a reference voltage VREF1600 provided by the voltage source G1601. An exemplary embodiment of the comparator C1601 is described in relation to [Fig. 17].

[0201] The operation of the circuit 1600 is as follows. When the voltage of the terminal VCC is lower than the reference voltage VREF1600, which happens at the time of starting the device 400, a current coming from the terminal SUPPLY is supplied by the transistor T1501, the transistor T1501 being conductive due to the dimensions of the resistor R1501. Indeed, the resistor R1501 has a rather high resistance to reduce the energy consumption of the device 400, for example a resistance of the order of 10 MOhm. The current I(R1501) passing through the resistor R1501 is given by the following mathematical formula: [Math 7] v (supply)-v (clamp) in which: Æ1501 - V(SUPPLY) is the voltage at the SUPPLY terminal; - V(CLAMP) is the voltage across flip-flop Cl501; and - R1501 is the resistance of resistor R1501.

[0202] When the voltage of the terminal VCC is higher than the reference voltage VREF1600, that is to say at the moment when the power supply circuits of the device 400 have started and are capable of providing a power supply voltage, the transistor T1501 is no longer conductive, and the node IN1500 receives a voltage from the terminal VCC.

[0203] [Fig. 17] shows an exemplary embodiment of a comparator circuit 1700 that can be used as comparator C1601 in the circuit 1600 of [Fig. 16].

[0204] The comparator circuit 1700 comprises two power supply nodes VSUPP1700 and VREF1700, two input nodes N1700+ and N1700- and an output node OUT1700. The power supply node VSUPP1700 receives a voltage higher than the voltage received by the node VREF1700, for example the power supply node VSUPP receives a voltage of the order of 6 V and the node VREF1700 receives a voltage of the order of 0 V. The input nodes N1700+ and N1700- receive the voltages to be compared. The node OUT1700 provides the voltage representing the result of the comparison of the voltages received by the nodes N1700+ and N1700-.

[0205] The circuit 1700 comprises, between the nodes VSUPP1700 and VREF1700, and on a first branch, a d-mode type transistor T1701, a resistor R1701, and a d-mode type transistor T1702. The drain of the transistor T1701 is connected, preferably connected, to the node VSUPP 1700, and the source of the transistor T1701 is connected, preferably connected, to a first terminal of the resistor R1701. The second terminal of the resistor R1701 is connected, preferably connected, to the drain and the gate of the transistor T1702. The source of the transistor T1702 is connected, preferably connected, to the node VREF1700.

[0206] The circuit 1700 further comprises, between the VSUPP node 1700 and the middle node between the resistor R1701 and the transistor T1702, and on a second branch, a d-mode type transistor T1703 and a resistor R1702. The drain of the transistor T1703 is connected, preferably connected, to the VSUPP1700 node, and the source of the transistor T1703 is connected, preferably connected, to a first terminal of the resistor R1702. The second terminal of the resistor R1702 is connected, preferably connected, to the middle node between the resistor R1701 and the transistor T1702. According to an alternative embodiment, the transistors T1701 and T1702 may be e-mode type transistors.

[0207] The circuit 1700 comprises, between the nodes VSUPP1700 and VREF1700, and on a third branch, a resistor R1703, a d-mode type transistor T1704, and a d-mode type transistor T1705. A first terminal of the resistor R1703 is connected, preferably connected to node VSUPP1700, and second terminal of resistor R1703 is connected, preferably connected, to the drain of transistor T1704 and to the gate of transistor T1703. The source of transistor T1704 is connected, preferably connected, to the drain of transistor T1705. The source of transistor T1705 is connected, preferably connected, to node VREF1700. The gate of transistor T1704 is connected, preferably connected, to node N1700+.

[0208] The circuit 1700 comprises, between the nodes VSUPP1700 and VREF1700, and on a fourth branch, a resistor R1704, a d-mode type transistor T1706, and the transistor T1705. A first terminal of the resistor R1704 is connected, preferably connected, to the node VSUPP1700, and a second terminal of the resistor R1704 is connected, preferably connected, to the drain of the transistor T1706 and to the gate of the transistor T1701. The source of the transistor T1706 is connected, preferably connected, to the drain of the transistor T1705. The gate of the transistor T1706 is connected, preferably connected, to the node N1700-.

[0209] The circuit 1700 comprises, between the nodes VSUPP1700 and VREF1700, and on a fifth branch, a transistor T1707 of e-mode type, and a transistor T1708 of e-mode type. The drain of the transistor T1707 is connected, preferably connected, to the node VSUPP1700, and the source of the transistor T1707 is connected, preferably connected, to the drain of the transistor T1708. The source of the transistor T1708 is connected, preferably connected, to the node VREF1700. The gate of the transistor T1707 is connected, preferably connected, to the gate of the transistor T1703.

[0210] The circuit 1700 comprises, between the nodes VSUPP1700 and VREF1700, and on a sixth branch, a d-mode type transistor T1709, and a d-mode type transistor T1710. The drain of the transistor T1709 is connected, preferably connected, to the node VSUPP1700, and the source of the transistor T1709 is connected, preferably connected, to the drain of the transistor T1710. The source of the transistor T1710 is connected, preferably connected, to the node VREF1700. The gate of the transistor T1709 is connected, preferably connected, to the gate of the transistor T1701.

[0211] According to a first embodiment, illustrated in [Fig. 17], the gate of the transistor T1708 is connected, preferably connected, to the drain of the transistor T1710, and the gate of the transistor T1710 is connected, preferably connected, to the drain of the transistor T1708.

[0212] According to a second embodiment, not illustrated in [Fig.17], the gates of the transistors T1708 and T1710 are connected, preferably connected, to each other and to the drain of the transistor T1708.

[0213] The circuit 1700 comprises, between the nodes VSUPP1700 and VREF1700, and on a seventh and last branch, a resistor R1705 and transistor T1711 of d-mode type. A first terminal of the resistor R1705 is connected, preferably connected, to the node VSUPP1700, and a second terminal of the resistor R1705 is connected, preferably connected, to the output node OUT1700. The drain of the transistor T1711 is connected, preferably connected, to the node OUT1700, and the source of the transistor T1711 is connected, preferably connected, to the node VREF1700. The gate of the transistor T1711 is connected, preferably connected, to the drain of the transistor T1710.

[0214] Transistors T1704 and T1705 are differential input transistors. Resistors R1701 and R1702 are bias resistors. Transistors T1701, T1702, T1703 and T1705 are bias transistors. Transistors T1707 and T1709 are voltage follower transistors. Transistors T1708 and T1710 are current comparators. The seventh branch is an output branch.

[0215] The comparator circuit 1700 operates as follows. When the gate voltage of transistor T1706 becomes higher than the gate voltage of transistor T1704, then the gate voltage of transistor T1709 becomes lower than the gate voltage of transistor T1707, which causes the gate voltage of transistor T1711 to become lower than the threshold voltage of transistor T1711. The output voltage VOUT1700 is then connected to the voltage VSUPP1700.

[0216] Figures 18 to 21 schematically represent, and partially in block form, embodiments of circuits which may be an overheat protection circuit 454 described in relation to [Fig.4].

[0217] [Fig. 18] is an electrical diagram of a first embodiment of an overheat protection circuit 1800 adapted to be part of the device 400.

[0218] The overheating protection regulation circuit 1800 is adapted to be connected to four connection terminals of the device 400, and more particularly: - to terminal DZ corresponding to connection terminal 477 of device 400 providing a positive supply voltage, for example of the order of 6 V; - to an OT_SENSOR terminal corresponding to an internal test connection terminal of the device 400, this terminal is optional; - to the reference terminal SGND corresponding to the reference connection terminal 472 of the device 400; and - to a test terminal DIAG_OT corresponding to the connection terminal 474 of the device 400.

[0219] The circuit 1800 comprises, between the terminals DZ and SGND, and on a first branch, two resistors R1801 and RI802. A first terminal of the resistor R1801 is connected, preferably connected, to the terminal DZ, and a second terminal of the resistor R1801 is connected, preferably connected, to the terminal OT_SENSOR. A first terminal of the resistor RI802 is connected, preferably connected, to the terminal OT_SENSOR, and a second terminal of the resistor RI802 is connected, preferably connected, to the terminal SGND. According to an alternative embodiment, the terminal DZ can be replaced by the terminal VDD.

[0220] According to one embodiment, the resistors R1801 and R1802 have different temperature coefficients. The resistor RI802 has a positive temperature coefficient and is positioned in an active area of ​​the device comprising the protection circuit 1800, for example at the power transistor 401. This will be described in more detail in relation to [Fig.20].

[0221] According to a first embodiment, the resistor R1801 has a zero temperature coefficient. The resistor R1801 may be a resistor made of a Silicon and Chromium alloy. In this case, the resistor R1801 is not formed at the same level as the resistor T1802. In particular, the resistor RI802 may be formed in the metallization levels of the structure in and on which the device 400 is formed, at the level of the control circuit 450, as described in relation to view (B) of [Fig.7]. This embodiment is described in more detail in relation to [Fig.20],

[0222] According to a second embodiment, the resistor R1801 may have a positive or negative temperature coefficient, but always different from the temperature coefficient of the resistor R1801. In this case the resistor R1801 may be positioned close to the resistor RI802 in the device 400.

[0223] The circuit 1800 comprises, between the terminals DZ and SGND, and on a second branch, two resistors RI803 and RI804. A first terminal of the resistor R1803 is connected, preferably connected, to the terminal DZ, and a second terminal of the resistor RI803 is connected, preferably connected, to a first terminal of the resistor RI804. A second terminal of the resistor RI804 is connected, preferably connected, to the terminal SGND. According to one embodiment, the resistors RI803 and R1804 are of the same type as the resistor R1801.

[0224] The circuit 1800 further comprises a comparator circuit C1801, of the type of the comparator circuit 1700 described in relation to [Fig. 17]. The comparator circuit C1801 comprises a first input terminal (+) connected, preferably connected, to the terminal OT_SENSOR, and a second input terminal (-) connected, preferably connected, to the middle node between the resistors RI803 and RI804. The comparator circuit C1801 comprises an output connected, preferably connected, to the terminal DIAG_OT. The comparator circuit C1801 further comprises power supply terminals not shown.

[0225] The circuit 1800 comprises, between the middle node between the resistors R1803 and R1804, and the terminal SGND, and on a third branch, a resistor R1805 and a transistor T1801 of e-mode type. A first terminal of the resistor R1805 is connected, preferably connected, to the middle node between the resistors RI803 and RI804, and a second terminal of the resistor RI805 is connected, preferably connected, to the drain of the transistor T1801. The source of the transistor T1801 is connected, preferably connected, to the terminal SGND. The gate of the transistor T1801 is connected, preferably connected, to the output of comparator circuit Cl801.

[0226] The operation of circuit 1800 is as follows. When the temperature at resistor RI802 increases, the voltage across resistor RI802 increases and the voltage across resistor R1801 does not change. The voltage between terminals OT_SENSOR and SGND then increases, and if it exceeds a reference voltage VREF1800, the output voltage of comparator circuit C1801 increases, which causes the output voltage, i.e., the voltage between terminals DIAG_OT and SGND, to decrease. The reference voltage VREF1800 is obtained by the voltage divider bridge formed by resistors RI803 and RI804, and by the hysteresis formed by transistor T1801 and resistor RI805.

[0227] [Fig. 19] shows a second embodiment of an overheat protection circuit 1900, adapted to form part of the device 400 described in relation to [Fig.4],

[0228] Circuit 1900 has elements in common with circuit 1800 of [Fig. 18]. These elements will not be described again and only the differences between circuits 1800 and 1900 will be highlighted.

[0229] Circuit 1900 comprises all the components of circuit 1800 but further comprises a fourth branch of components between terminals DZ and SGND. Furthermore, in circuit 1900 the output of comparator circuit C1801 is connected, preferably connected, only to the gate of transistor T1801 and no longer to terminal DIAG_OT.

[0230] Said fourth branch comprises two resistors R1901 and R1902, and a transistor T1901 of e-mode type. A first terminal of the resistor R1901 is connected, preferably connected, to the terminal DZ, and a second terminal of the resistor R1901 is connected, preferably connected, to the terminal DIAG_OT. A first terminal of the resistor R1902 is connected, preferably connected, to the terminal DIAG_OT, and a second terminal of the resistor R1902 is connected, preferably connected, to the drain of the transistor T1901. The resistors R1901 and R1902 both have positive temperature coefficients. The source of the transistor T1901 is connected, preferably connected, to the terminal SGND. The gate of the transistor T1901 is connected, preferably connected to the gate of the transistor T1801 and to the output of the comparator circuit C1801.

[0231] The operation of circuit 1900 is as follows. When the temperature at resistor RI802 increases, the voltage across resistor RI802 increases and the voltage across resistor R1801 does not change. The voltage between terminals OT_SENSOR and SGND then increases, and if it exceeds the reference voltage VREF1800, the output voltage of comparator circuit C1801 increases, which causes the output voltage to decrease, i.e. the voltage between terminals DIAG_OT and SGND also decreases.

[0232] In addition, resistors R1901, R1902 and transistor T1901 form an element buffer for providing information about the occurrence of overheating to an external controller, for example a microcontroller. Resistor R1902 is used to limit the current flowing through transistor T1901. Indeed, in a certain operating mode of the device 400, circuit 1900 can be deactivated if the user of the device no longer wishes to have access to the overheating protection. In this case, if the output terminal DIAG_OT is connected, preferably connected, to the DZ terminal or to the VDD terminal, resistor R1902 then makes it possible to reduce the DIAG_OT output voltage.

[0233] [Fig.20] is a top view of the same practical example of embodiment of the device 400 described in relation to [Fig.6], in which the positioning of the resistors R1801 and R1802 is shown according to the first embodiment described in relation to [Fig. 18].

[0234] As described previously, the resistor R1801 has a zero temperature coefficient and is placed at the level of the control circuit 450 (location R2 in [Fig.20]) so as to be impacted minimally by a possible increase in temperature of the transistor 401.

[0235] Resistor RI802 has a positive temperature coefficient and is placed at the transistor 401 (location RI in [Fig.20]) so as to see the same temperature variation as transistor 401. Thus, resistor R1802 sees the voltage across its terminals increase in the event of transistor 401 overheating.

[0236] [Fig. 21] shows a third embodiment, and a preferred embodiment, of an overheat protection circuit 2100, adapted to be part of the device 400 described in relation to [Fig. 4]. [Fig. 21] comprises two views (A) and (B), view (A) illustrates, partially in block form, the overheat protection circuit 2100, and view (B) illustrates, a part of the overheat protection circuit 2100.

[0237] Circuit 2100 has elements in common with circuit 1800 of [Fig. 18] and circuit 1900 of [Fig. 19]. These elements will not be described again and only the differences between circuits 1800, 1900, and 2100 will be highlighted.

[0238] The circuit 2100 comprises most of the components of the circuit 1900 but comprises, in place of the resistor RI802, a resistor with modifiable resistance and its control circuit CMD1801. In addition, in the circuit 2100 the transistor T1801 is replaced by a switch 12101 comprising a control terminal connected, preferably connected, only to the gate of the transistor T1901 and no longer to the terminal DIAG_OT.

[0239] In [Fig.21], the resistor R2101 is formed by four resistors R2101-1 to R2101-4, of which three resistors R2101-1 to R2101-3 are selectable via switches 12102-1 to 12102-3. According to one example, the switches 12102-1 to 12102-3 are implemented by e-mode type transistors. The person skilled in the art will know how to adjust the number of resistors forming the resistor R2101 to the number necessary for its application.

[0240] More particularly, resistors R2101-1, R2101-2, R2101-3, and R2101-4 are connected in series between terminals OT_SENSOR and SGND. Switch 12102-1 is connected, preferably connected, in parallel with resistor R2101-1, such that if switch 12102-1 is conductive, resistor R2101-1 is short-circuited. Similarly, switch 12102-2 is connected, preferably connected, in parallel with resistor R2101-2, and switch 12102-3 is connected, preferably connected, in parallel with resistor R2101-3. According to one example, switches 12101-1 to 12101-3 are transistors.

[0241] The switches 12102-1 to 12102-3 are each controlled by a CMD2100 control circuit detailed in relation to view (B) of [Fig.21]. The CMD2100 control circuit comprises two test input terminals INA and INB, and an output terminal OUTCMD providing a control voltage. According to a variant, certain CMD2100 control circuits can be connected to the control terminal of the switch 12102-1, 12102-2, or 12102-3 by an inverter circuit (not shown in [Fig.21]).

[0242] The control circuit CMD2100 is further connected to the terminals DZ, SGND, and to test terminals EWS1 and EWS2. The control circuit 2100 includes a resistor R2103 disposed between the terminals DZ and EWS1, a resistor R2105 disposed between the terminals DZ and OUTCMD, and a resistor R2106 disposed between the terminals SGND and EWS2.

[0243] The control circuit CMD2100 further comprises a fuse MF2101 arranged between the terminals EWS1 and EWS2. The fuse 2100 makes it possible to permanently set the value of the resistor R2101. A more detailed example of the fuse 2100 is described in relation to [Fig.22].

[0244] The control circuit CMD2100 comprises two e-mode type transistors T2101 and T2102. The source and the gate of the transistor T2101 are connected, preferably connected, to a node N2100. The drain of the transistor T2101 is connected, preferably connected, to the source and the gate of the transistor T2102. The drain of the transistor T2102 is connected, preferably connected, to the terminal EWS2.

[0245] The control circuit CMD2100 comprises two transistors T2103 and T2104 of e-mode type, these transistors are test transistors. The source of the transistor T2103 is connected, preferably connected, to the terminal DZ. The drain of the transistor T2103 is connected, preferably connected, to the source of the transistor T2104. The drain of the transistor T2104 is connected, preferably connected, to the node N2100. The gate of the transistor T2103 is connected, preferably connected, to the terminal INA. The gate of the transistor T2104 is connected, preferably connected, to the INB terminal.

[0246] The control circuit CMD2100 further comprises a resistor R2104 and a transistor T2105. The resistor R2104 is arranged between the terminal EWS1 and the node N2100. The source of the transistor T2105 is connected, preferably connected, to the output terminal OUTCMD. The drain of the transistor T2105 is connected, preferably connected, to the terminal EWS2. The gate of the transistor T2105 is connected, preferably connected, to the node N2100.

[0247] The control circuit CMD2100 controlling the switch 12102-1 receives on its terminal INA the voltage OUT_LOGIC, and on its terminal INB a test voltage EWS_TESTMODE. The control circuit CMD2100 controlling the switch 12102-2 receives on its terminal INA a voltage RSENSE, and on its terminal INB a test voltage EWS_TESTMODE. The control circuit CMD2100 controlling the switch 12102-3 receives on its terminal INA a voltage GATE_SENSE, and on its terminal INB a test voltage EWS_TESTMODE.

[0248] The operation of circuit 2100 is the same as that of circuit 1900, but additionally includes a phase of programming the value of resistor R2101. The programming phase includes two steps, a step of estimating the value of the resistor to be programmed, and a programming step.

[0249] During the estimation step, the control circuits CMD2100 use the transistors T2103 and T2105 to control the transistor T2104, and therefore to control the output voltage OUTCMD. Several values ​​of the resistor R2101 are thus tested to see which value corresponds the most. This step is generally implemented at the time of manufacturing the device 400.

[0250] During the programming step, the MF2101 fuses are left on or off depending on the value determined in the previous step.

[0251] Allowing the value of resistor R2101 to be programmed makes overheating detection much more precise.

[0252] [Fig.22] is a sectional view illustrating one embodiment of a fuse of the type MF2101 fuse described in connection with [Fig.21].

[0253] The fuse is formed between two levels of metallizations of the device 400, and has an hourglass shape.

[0254] When a current, greater than a threshold current, is applied between terminals EWS1 and EWS2, the metal forming the fuse is broken. If the fuse is open, or non-conducting, then the voltage at the gate of transistor T2104 is increased to a level equal to the sum of the threshold voltages of transistors T2101 and T2102, which turns transistor T2104 on. This connects the output terminal OUTCMD to the reference terminal SGND.

[0255] Figures 23 to 26 represent schematically, and partially in the form of blocks, circuit embodiments which may be a driver circuit 451 described in relation to [Fig.4].

[0256] [Fig.23] is an electrical diagram of a first embodiment of a control circuit 2200 adapted to be part of the device 400 described in relation to [Fig.4]. The control circuit 2200 forms the logic circuits 452 and the control circuit 451 of the device 400.

[0257] The control circuit 2200 is adapted to be connected to four connection terminals of the device 400, and more particularly: - to an input terminal IN corresponding to the connection terminal 475 of the device 400; - to terminal VDD corresponding to connection terminal 476 of device 400; - to the reference terminal SGND corresponding to the reference connection terminal 472 of the device 400; and - to the DRAIN terminal corresponding to the internal drain terminal of the power transistor 401 of the device 400.

[0258] The circuit 2200 comprises a logic circuit 2201 connected to the terminals IN and SGND, and comprises two output nodes OUTL2201 and OUTL2202. The logic circuit 2201 makes it possible to transform a signal received on the input terminal IN into a control instruction. According to one example, the circuit 2201 may be a logic gate of the "NAND" type. According to one example, the output OUTL2201 transmits a supply voltage. According to one example, the logic circuit 2201 may, in addition, receive the voltages DIAG_OT and VDS as input.

[0259] The circuit 2200 further comprises a voltage regulator circuit 2202 (REG) providing a current to the node OUTL2201. The circuit 2202 may be one of the voltage regulator circuits described in relation to FIGS. 7 to 16 or one of their variants.

[0260] The circuit 2200 further comprises, at the node OUTL2201 and the terminal SGND, an e-mode type transistor T2201 coupled in parallel with a resistor R2201, and an e-mode type transistor T2202. More particularly, the drain of the transistor T2201 and a first terminal of the resistor R2201 are connected, preferably connected, to the node OUTL2201. The source of the transistor T2201 and a second terminal of the resistor R2201 are connected, preferably connected, to the drain of the transistor T2202. The source of the transistor T2202 is connected, preferably connected, to the terminal SGND. The gate of the transistor T2201 is connected, preferably connected, to the node OUTL2202.

[0261] The circuit 2200 further comprises an inverter gate INV2201 connecting the node OUTL2202 to the gate of the transistor T2202.

[0262] Circuit 2200 further comprises a bootstrap circuit C2201 (ON PULL UP) having an output connected to a node N2201 and providing a voltage high enough to control the power transistor 401 of the device 400. The circuit C2201 is within the reach of the person skilled in the art.

[0263] The circuit 2200 further comprises an e-mode type transistor T2203 between the node N2201 and the terminal SGND. The drain of the transistor T2203 is connected, preferably connected, to the node N2201, and the source of the transistor T2203 is connected, preferably connected, to the terminal SGND. The gate of the transistor T2203 is connected, preferably connected, to the drain of the transistor T2202.

[0264] The circuit 2200 further comprises, between the terminals VDD and SGND, two e-mode type transistors T2204 and T2205. The drain of the transistor T2204 is connected, preferably connected, to the terminal VDD, and the source of the transistor T2204 is connected, preferably connected, to the drain of the transistor T2205. The source of the transistor T2205 is connected, preferably connected, to the terminal SGND. The gate of the transistor T2204 is connected, preferably connected, to the node N2201. The gate of the transistor T2205 is connected, preferably connected, to the drain of the transistor T2202. The transistor T2204 is a pull-up transistor, and the transistor T2205 is a pull-down transistor.

[0265] Finally, the circuit 2200 is connected to the power transistor 401 in the following manner. The drain of the transistor 401 is connected, preferably connected, to the DRAIN terminal, and the source of the transistor 401 is connected, preferably connected, to the SGND terminal. The gate of the transistor 401 is connected, preferably connected, to the middle node between the transistors T2204 and T2205. In addition, the transistor T2205 is placed as close as possible to the transistor 401 to promote the discharge of the gate of the transistor 401 and / or to ensure good current communication between the transistor T2205 and the gate of the transistor 401. This is described in more detail in relation to [Fig.24].

[0266] The operation of circuit 2200 is as follows.

[0267] When the signal received by terminal IN is in a low state, the output of logic circuit 2201 is in a low state. Transistor T2201 does not conduct, and transistor T2202 conducts. Transistors T2203 and T2205 are not conductive. Transistor T2204 is conductive. Power transistor 401 is therefore conductive.

[0268] When the signal received by the IN terminal is in a high state, the output of the logic circuit 2201 is in a high state. According to an alternative embodiment, the logic circuit 2201 could, in addition, receive as input the test voltages supplied by the terminals DIAG_OT and DIAG_OC, if one of these two voltages is in a high state then the output of the logic circuit is also in a high state. The transistor T2201 is then conductive, and the transistor T2202 does not conduct. The transistors T2203 and T2205 are conductive. The transistor T2204 is not conductive. The power transistor 401 is therefore non-conductive.

[0269] [Fig.24] is a schematic top view of a portion of the device 400 comprising a portion of the driving circuit 2200 described in relation to [Fig.23] and a portion of the power transistor 401.

[0270] In [Fig.24], the transistor 401 is constituted by an assembly of several e-mode type transistors as described in relation to [Fig.5]. These transistors each comprise source 2301 (SOURCE), gate 2302 (GATE) and drain 2304 (DRAIN) regions formed on an active region 2303 (ACTIVE) of a structure of the type of structure 100 of [Fig.l].

[0271] In addition, like transistor 401, transistor T2205 is also composed of an assembly of several transistors of the same type. These transistors each comprise source 2311 (SOURCE), gate 2312 (GATE) and drain 2314 (DRAIN) regions formed on an active region 2313 of the structure.

[0272] According to one embodiment, and to avoid current losses as much as possible, the transistors T2205 are arranged as close as possible to the transistor 401, and for this reason have their drain regions 2311 in direct contact with the gate regions of the transistor 401.

[0273] [Fig.25] represents a second embodiment of a control circuit 2400, adapted to form part of the device 400 described in relation to [Fig.4].

[0274] Circuit 2400 has elements in common with circuit 2200 of [Fig.23]. These elements will not be described again and only the differences between circuits 2200 and 2400 will be highlighted.

[0275] Circuit 2400 differs from circuit 2200 in that it includes a transistor T2401. The drain of transistor T2401 is connected, preferably connected, to the drain of transistor T2201, and the source of transistor T2401 is connected, preferably connected, to the first terminal of resistor R2201. The first terminal of resistor R2201 is no longer connected to the drain of transistor T2201 except via transistor T2401, the second terminal of resistor R2201 still being connected to the drain of transistor T2202. The gate of transistor 2401 is connected, preferably connected, to the source of transistor T2201. Adding transistor T2401 makes it possible to add a current source and reduce the size of resistor R2201. The supplied current is equal to the ratio between the threshold voltage of transistor T2401 and the resistance of resistor R2201.

[0276] [Fig.26] represents a second embodiment of a control circuit 2500, adapted to form part of the device 400 described in relation to [Fig.4].

[0277] Circuit 2500 has elements in common with circuit 2200 of [Fig.23] and circuit 2400 of [Fig.25]. These elements will not be described again and only the differences between circuits 2200, 2400, and 2500 will be highlighted.

[0278] Circuit 2500 differs from circuit 2200 in that it includes an AND2501 gate of the "AND" type for controlling transistor T2201.

[0279] The AND2501 gate comprises two inputs, a first being connected to the OUTL2202 node and a second being connected to the gate of the transistor 401.

[0280] The addition of the AND2501 gate makes it possible to avoid the appearance of a short circuit at the transistors T2201 and T2202 during a transition from a high state to a low state of the voltage at the OUTL2202 node.

[0281] Figures 27 to 29 schematically represent, and partially in block form, an embodiment of a circuit which may be an overcurrent protection circuit 453 described in relation to [Fig.4].

[0282] [Fig.27] is an electrical diagram of an embodiment of an overcurrent protection circuit 2600 adapted to be part of the device 400 described in relation to [Fig.4]. Shown in [Fig.27] are the overcurrent protection circuit 2600, the power transistor 401 and its driver circuit 451 of the device 400.

[0283] The overcurrent protection circuit 2600 is adapted to be connected to five connection terminals of the device 400, and more particularly: - to a drain terminal DRAIN of the transistor 401 corresponding to the connection terminal 470 of the device 400; - to the reference terminal SGND corresponding to the reference connection terminal 472 of the device 400; and - to a reference terminal OUT_LOGIC corresponding to the internal connection terminal 452OUT of the output of the logic circuits 452 of the device 400; and - to a test terminal DIAG_OC corresponding to the test connection terminal 473 of the device 400; - to terminal DZ corresponding to connection terminal 477 of device 400, or, according to a variant, to terminal VDD; - to a VSUPP terminal corresponding to an internal power supply terminal of the device 400; and - to an IN_LOGIC terminal corresponding to the internal connection terminal 452IN of the input of the logic circuits 452 of the device 400.

[0284] The power transistor 401 has its drain connected, preferably connected, to the DRAIN terminal, and has its source connected, preferably connected, to the SGND terminal. The transistor 401 receives on its gate a control voltage from the driving circuit 451.

[0285] The circuit 2600 comprises a level converter circuit LS2601 (LS) (Level Shifter) comprising two inputs and one output. The first input of the circuit 2600 is connected, preferably connected, to the terminal OUT_LOGIC.

[0286] The circuit 2600 further comprises, on a first branch between the terminals DRAIN and SGND, an e-mode type transistor T2601 and a resistor R2601. The drain of the transistor T2601 is connected, preferably connected, to the terminal DRAIN, and the source of the transistor T2601 is connected, preferably connected, to a first terminal of the resistor R2601. A second terminal of the resistor R2601 is connected, preferably connected, to the SGND terminal. The gate of the transistor T2601 is connected, preferably connected, to the output of the level converter circuit LS2601.

[0287] The circuit 2600 further comprises, on a second branch between the terminals VSUPP and SGND, a resistor R2602 and a transistor T2602 of e-mode type. A first terminal of the resistor R2602 is connected, preferably connected to the terminal VSUPP, and a second terminal of the resistor R2602 is connected, preferably connected, to the drain of the transistor T2602. The source of the transistor T2602 is connected, preferably connected, to the terminal SGND, and the gate of the transistor T2602 is connected, preferably connected to the second input of the voltage converter circuit LS2601.

[0288] According to one embodiment, the transistor T2602 is a sister transistor of the power transistor 401, that is to say that the transistor T2602 is a transistor of the same type as the transistor 401, and, in addition, the dimensions of the transistor T2602 are approximately 10000 times smaller than the dimensions of the transistor 401.

[0289] Transistors T2601 and T2602 are transistors suitable for high voltages, i.e. suitable for supporting a voltage of the order of 650 V between their source and their drain. In addition, transistors 401 and T2602 are manufactured in parallel using the same processes.

[0290] The circuit 2600 further comprises a comparator circuit C2601 adapted to compare voltages of the first and second branches. More particularly, the comparator circuit C2601 comprises a first input (+) connected, preferably connected, to the middle node between the transistor T2601 and the resistor R2601, and a second input (-) connected, preferably connected, to the middle node between the resistor R2602 and the transistor T2602. A detailed example of a comparator circuit is described in relation to [Fig. 17]. Thus, the comparator circuit compares the voltage across the resistor R2601, called the voltage VDS_SENSE, and the voltage across the transistor T2602, called the voltage VRSENSE. The voltage VRSENSE represents the reference voltage with respect to which the voltage VDS_SENSE is compared, and is given by the following mathematical formula: [Math 8] VRSENSE = which: R{T2602 J+Æ2602 - R(T2602) represents the internal resistance of transistor T2602; and - R2602 represents the resistance of resistor R2602.

[0291] The circuit 2600 further comprises, on a third branch between the terminals DZ and SGND, two resistors R2603 and R2604 and a transistor T2603 of e-mode type. A first terminal of the resistor R2603 is connected, preferably connected, to the terminal DZ, and a second terminal of the resistor R2603 is connected, preferably connected, to the terminal DIAG_OC. A first terminal of the resistor R2604 is connected, preferably connected to terminal DIAG_OC, and a second terminal of resistor R2604 is connected, preferably connected, to the drain of transistor T2603. The source of transistor T2603 is connected, preferably connected, to terminal SGND, and the gate of transistor T2603 is connected, preferably connected to the output of comparator circuit C2601.

[0292] The circuit 2600 further comprises, on a fourth branch between the terminals DIAG_OC and SGND, a resistor R2605 and a transistor T2604 of e-mode type. A first terminal of the resistor R2605 is connected, preferably connected to the terminal DIAG_OC, and a second terminal of the resistor R2605 is connected, preferably connected, to the drain of the transistor T2604. The source of the transistor T2604 is connected, preferably connected, to the terminal SGND, and the gate of the transistor T2604 is connected, preferably connected to the terminal IN_LOGIC.

[0293] The circuit 2600 further comprises, on a fifth branch between the terminals DZ and SGND, a resistor R2606 and a transistor T2605 of e-mode type. A first terminal of the resistor R2606 is connected, preferably connected to the terminal DZ, and a second terminal of the resistor R2606 is connected, preferably connected, to the drain of the transistor T2605 and to the terminal IN_LOGIC. The source of the transistor T2605 is connected, preferably connected, to the terminal SGND, and the gate of the transistor T2605 is connected, preferably connected to the terminal DIAG_OC.

[0294] The operation of circuit 2600 is described in relation to [Fig.28].

[0295] [Fig.28] represents voltage and current timing diagrams of circuit 2600 and device 400.

[0296] More particularly, [Fig.27] comprises: - an input voltage V(IN) representing the voltage at the connection terminal 475 (IN) of the device 400; - a voltage V(DS) representing the voltage at the conduction terminals of the power transistor 401 of the device 400; - a current I(DS) representing the current between the conduction terminals of the power transistor 401 of the device 400; and - a voltage V(DIAG_OC) representing the voltage at the test terminal 473 of the device 400.

[0297] At an initial time t0, the input voltage V(IN) is in a high state, for example 6 V, and the transistor 401 is therefore non-conducting. The current flowing through the transistor 401 is less than a threshold current IDS_TH, and the voltage V(DS) across the transistor 401 is in a high state, for example 6 V, and constant.

[0298] At a time t1, after time t0, the voltage V(IN) goes to a low state, the transistor 401 becomes conductive, the voltage V(DS) goes below a threshold voltage VDS_TH. The gates of the transistors 401, T2601, T2602, and T2603 receive a voltage lower than the threshold voltages of these transistors. The gate of transistor T2604 always receives a high voltage, and transistor T2604 forces the voltage V(DIAG_OC) to remain high.

[0299] Between time t1 and a time t2, subsequent to time t1, the current I(DS) increases, for example following a short circuit in the device 400. At time t2, the current I(DS) exceeds the threshold current IDS_TH. The comparator C2601 detects this and the voltage V(DIAG_0C) goes to a low state at time t2.

[0300] Between time t2 and a time t3, subsequent to time t2, voltage V(DIAG_0C) remains in the low state, and circuit 2600 forces transistor 401 to be non-conductive. Voltage V(DS) then goes to a high state, and current I(DS) decreases until it returns to its initial state. Voltage V(DIAG_0C) then alerts the circuits of device 400 by remaining in the low state.

[0301] After time t3, voltage V(DIAG_0C) returns to a high state, and the alert is terminated.

[0302] [Fig.29] is a top view of the same practical example of embodiment of the device 400 described in relation to FIGS. 6 and 20, in which the positioning of transistor T2602 is shown according to one embodiment.

[0303] Transistor T2602 is placed between two of the assemblies forming transistor 401. By being located in this way, transistor T2602 is adapted to receive the same current as power transistor 401.

[0304] An advantage of this embodiment is that it provides overcurrent protection with a response time fast enough that an overcurrent does not cause damage to the power transistor 401.

[0305] Figures 30 to 32 very schematically represent embodiments of connection terminals which may be one of the connection terminals 470 to 478 of the device 400 described in relation to [Fig.4].

[0306] [Fig.30] describes a structure 2900 comprising a first embodiment of a connection terminal which may be part of the device 400.

[0307] The structure 2900 comprises the structure 100 described in relation to [Fig.l], and comprises a substrate 101 covered with a layer of Gallium Nitride 102.

[0308] The structure 2900 further comprises, on the structure 100, a stack 2900M forming metallization levels, in particular three metallization levels in [Fig.30]. More particularly, the stack 2900 comprises: - an electrically insulating layer 2901 resting on and in contact with the layer 102 of the structure 100; - an electrically conductive layer 2902, for example a metallic layer, resting on and in contact with the layer 2901; - an electrically insulating layer 2903 resting on and in contact with the layer 2902; - an electrically conductive layer 2904, for example a metallic layer, resting on and in contact with the layer 2903; - an electrically insulating layer 2905 resting on and in contact with layer 2904; and - an electrically conductive layer 2906, for example a metallic layer, resting on and in contact with the layer 2905.

[0309] Layer 2906 is used to form a connection terminal, and is connected to an I / O node. The connection terminal may be connected to other connection terminals, for example, by a wire bonding process.

[0310] According to one embodiment, the conductive layer 2902 is connected, preferably connected to the source terminal of the power transistor 401.

[0311] The connection terminal formed by the layer 2906 is electrically protected from the structure 100, and from the components which are likely to be formed there, by the parasitic capacitances formed by the insulating layers 2901, 2903 and 2905.

[0312] [Fig.31] describes a structure 3000 comprising a second embodiment of a connection terminal which may be part of the device 400.

[0313] The structure 3000 comprises elements in common with the structure 2900 described in relation to [Fig. 30]. These common elements will not be described again, and only the differences between the structures 2900 and 3000 will be highlighted.

[0314] Unlike structure 2900, structure 3000 comprises only two levels of metallizations, and thus does not comprise layers 2905 and 2906. The connection terminal is formed in layer 2904.

[0315] The connection terminal formed by the layer 2904 is electrically protected from the structure 100, and from the components which are likely to be formed there, by the parasitic capacitances formed by the insulating layers 2901 and 2903.

[0316] [Fig.32] describes a structure 3100 comprising a third embodiment of a connection terminal which may be part of the device 400.

[0317] The structure 3100 includes elements in common with the structure 2900 described in relation to [Fig. 30] and with the structure 3000 described in relation to [Fig. 31]. These common elements will not be described again, and only the differences between the structures 2900 and 3000 will be highlighted.

[0318] Like structure 2900, structure 3100 comprises three levels of metallizations, but further comprises electrically conductive vias 3101 connecting layer 2906 to layer 2905. The connection terminal is still formed in layer 2906.

[0319] The connection terminal formed by the layer 2906 is electrically protected from the structure 100, and from the components which are likely to be formed there, by the capacitors parasites formed by the insulating layers 2901 and 2903.

[0320] Figures 33 to 35 show embodiments of applications of the device 400 described in relation to Figures 4 to 31.

[0321] [Fig. 33] represents, schematically and partially in block form, a first embodiment of an application of the device 400. More particularly, [Fig. 32] comprises a view (A) illustrating an electrical diagram of the first embodiment, and a view (B) illustrating timing diagrams illustrating the operation of the first embodiment. In view (A), the device 400 is represented in block form in the same way as in [Fig. 4]. All the variants of the circuits of the device 400 described in relation to FIGS. 5 to 32 are applicable here.

[0322] In view (A), the device 400 is used in an electronic system 3200 to form a Boost Converter circuit, i.e. a switching power supply adapted to convert a DC input voltage VIN3200 into a DC output voltage VOUT3200 of higher value. According to one example, the voltage VIN3200 is of the order of 220 V or 311 V. According to one example, the voltage VOUT3200 is of the order of 400 V.

[0323] The system 3200 includes the device 400. The input terminal 475 (IN) of the device 400 receives a control voltage from, for example, a processor external to the system 3200. The terminal 478 (VCC) receives a supply potential VCC3200. The test terminals 474 (DIAG_OT) and 473 (DIAG_OC) are used as test terminals of the system 200.

[0324] The system 3200 further comprises an input transistor C3201 disposed between the input node IN2300, receiving the input voltage VIN2300, and a reference node REF3200. Thus, a first terminal of the capacitor C3201 is connected, preferably connected, to the node IN2300, and a second terminal of the capacitor C3201 is connected, preferably connected, to the reference node REF3200. The capacitor C3201 is a filter capacitor.

[0325] The system 3200 further comprises, between the input node IN2300 and the drain terminal 470 (DRAIN) of the device 400, an output coil L3201. A first terminal of the coil L3201 is connected, preferably connected, to the node IN3200, and a second terminal of the coil 3201 is connected, preferably connected, to the terminal 470 of the device 400. The coil L3201 is used as a converter of a DC voltage into a DC voltage. More particularly, the coil L3201 stores energy and makes it possible to create an additional power rail.

[0326] The system 3200 further comprises, between the terminal 477 (DZ) and the reference terminal 472 of the device 400, a Zener diode D3201. The cathode of the Zener diode 3201 is connected, preferably connected, to the terminal 477, and the anode of the Zener diode D3201 is connected, preferably connected, to the terminal 472. The diode D3201 can re present the external diode used in the voltage regulator and high voltage circuits of the device 400.

[0327] The system 3200 further comprises, between terminal 476 (VDD) and the reference terminal 472 of the device 400, a filter capacitor C3202. A first terminal of the capacitor C3202 is connected, preferably connected, to terminal 476, and a second terminal of the capacitor C3202 is connected, preferably connected, to terminal 472.

[0328] The system 3200 further optionally comprises, between terminal 476 (VDD) and reference terminal 472 of the device 400, a resistor R3201 and a capacitor C3203. A first terminal of the resistor R3201 is connected, preferably connected, to terminal 476, and a second terminal of the resistor R3201 is connected, preferably connected, to a first terminal of the capacitor C3203. A second terminal of the capacitor C3203 is connected, preferably connected, to terminal 472.

[0329] The system 3200 further comprises, between the drain terminal 470 and the terminal 471 of the device 400, a Schottky diode D3202 and an output capacitor C3204. The anode of the diode D3202 is connected, preferably connected, to the terminal 470, and the cathode of the diode D3202 is connected, preferably connected, to the output node OUT3200 of the system 3200, providing the output voltage VOUT3200, and to a first terminal of the capacitor C3206. The second terminal of the capacitor C3206 is connected, preferably connected, to the terminal 471.

[0330] The operation of the system 3200 is described in relation to view (B). View (B) includes the following timing diagrams: - the timing diagram of the output voltage VOUT3200; - the timing diagram of the control voltage V(IN) received by terminal 475; - the timing diagram of the output current I(OUT); and - the timing diagram of the current I(L3201) passing through the coil L3201.

[0331] The control voltage V(IN) is a square wave voltage oscillating between a high state and a low state. The output voltage VOUT3200 is also a square wave voltage whose maximum voltage stabilizes little by little. More particularly, at the start of the system 3200, not all the voltage regulator circuits are directly operational. The output voltage VOUT3200 and the output current I(OUT) therefore have a pseudoperiodic appearance while all the voltage regulator circuits start, then each stabilizes into a square wave signal alternating between a high state and a low state.

[0332] [Fig. 34] shows, schematically and partially in block form, a second embodiment of an application of the device 400. In [Fig. 34], the device 400 is shown in block form in the same way as in [Fig. 4]. All the variants of the circuits of the device 400 described in relation to FIGS. 5 to 31 are applicable here.

[0333] In [Fig.34], the device 400 is used in an electronic system 3300 to form a symmetrical converter circuit, or a push-pull converter with a half-bridge configuration, i.e. a circuit adapted to convert a DC input voltage VIN3300 into a DC output voltage VOUT3300. According to one example, the voltage VIN3200 is of the order of 220 V or 311 V. According to one example, the voltage VOUT3200 is of the order of 400 V.

[0334] The system 3300 comprises two devices 400, referenced in [Fig.34] devices 400-1 and 400-2. The elements relating to the device 400-1 have the suffix "-1" at the end of the reference, and the elements relating to the device 400-2 have the suffix "-2" at the end of the reference.

[0335] The system 3300 further comprises a control circuit 3301 adapted to implement the devices 400-1 and 400-2. The control circuit 3301 comprises the following terminals: - an input terminal IN-1 connected, preferably connected, to the input terminal 475-1 (IN) of the device 400-1; - a test terminal TEST-1 connected, preferably connected, to the test terminals 474-1 (DIAG_OT) and 473-1 (DIAG_OC) of the devices 400-1; - a first reference terminal REF-1 connected, preferably connected, to terminal 472-1 (SGND) of device 400-1; - a VCC power supply terminal connected, preferably connected, to terminal 478-2 (VCC) of the device 400-2; - an input terminal IN-2 connected, preferably connected, to the input terminal 475-2 (IN) of the device 400-2; - a test terminal TEST-2 connected, preferably connected, to the test terminals 474-2 (DIAG_OT) and 473-2 (DIAG_OC) of the devices 400-2; and - a first reference terminal REF-2 connected, preferably connected, to terminal 472-2 (SGND) of device 400-2.

[0336] The system 3300 further comprises, between the input node IN3300, receiving the input voltage VIN3300, and the node 471-1 of the device 400-1, and the node 470-2 of the device 400-2, a coil L3301. A first terminal of the coil L3301 is connected, preferably connected, to the node IN3300, and a second terminal of the coil L3301 is connected, preferably connected, to the terminals 471-1 and 470-2. The coil L3301 is used as a converter of a DC voltage into a DC voltage. More particularly, the coil L3301 stores energy and makes it possible to create an additional power rail.

[0337] The system 3300 further comprises, between the output node OUT3300, providing the output voltage VOUT3300, and the node 470-1 of the device 400-1, a capacitor C3301. A first terminal of the capacitor C3301 is connected, preferably connected to node OUT3300, and a second terminal of capacitor C3301 is connected, preferably connected, to a reference terminal.

[0338] The system 3300 further comprises, between terminal 478-1 of the device 400-1, the power supply terminal VCC of the control circuit and terminal 478-2 of the device 400-2, a diode D3301. The cathode of the diode D3301 is connected, preferably connected, to terminal 478-1, and the anode of the diode D3301 is connected, preferably connected, to terminal VCC and terminal 478-2.

[0339] The system further comprises, between terminal 478-1 of device 400-1 and the power supply terminal VCC of control circuit 301, a capacitor C3302. A first terminal of capacitor C3302 is connected, preferably connected, to terminal 478-1, and a second terminal of capacitor C3302 is connected, preferably connected, to terminal VCC. Capacitor C3302 is used to shift a level voltage (bootstrap capacitor). More particularly, capacitor C3302 makes it possible to modify the voltage at terminal VCC, from a voltage referenced relative to the voltage at terminal 472-1, to a voltage referenced relative to an output reference voltage.

[0340] The system 3300 further comprises, between terminal 477-1 of the device 400-1, and terminal REF-1 of the device 400-1, a Zener diode D3302. The cathode of the diode D3302 is connected, preferably connected, to terminal 477-1, and the anode of the diode D3302 is connected, preferably connected, to terminal REF-1.

[0341] The system 3300 further comprises, between terminal 476-1 of the device 400-1, and terminal REF-1 of the device 400-1, a capacitor C3303. A first terminal of the capacitor C3303 is connected, preferably connected, to terminal 476-1, and a second terminal of the capacitor C3303 is connected, preferably connected, to terminal REF-1. The capacitor C3303 makes it possible to power the control circuit of the device 400-1.

[0342] The system 3300 further and optionally comprises, between terminal 476-1 of the device 400-1, and terminal REF-1 of the device 400-1, a resistor R3301 and a capacitor C3304. A first terminal of the resistor R3301 is connected, preferably connected, to terminal 476-1, and a second terminal of the resistor R3301 is connected, preferably connected, to a first terminal of the capacitor C3304. A second terminal of the capacitor C3304 is connected, preferably connected, to terminal REF-1.

[0343] The system further comprises, between terminal 476-1 of device 400-1 and terminals 474-1 and 473-1 of device 400-1, a resistor R3302. A first terminal of resistor R3302 is connected, preferably connected, to terminal 476-1, and a second terminal of resistor R3302 is connected, preferably connected, to terminals 474-1 and 473-1. Resistor R3302 is a pull-up resistor for creating a NOR type logic function taking as input the output voltages of terminals 474-1 and 473-1.

[0344] The system 3300 further comprises, between terminal 477-2 of the device 400-2, and terminal REF-2 of the device 400-2, a Zener diode D3303. The cathode of the diode D3303 is connected, preferably connected, to terminal 477-2, and the anode of the diode D3303 is connected, preferably connected, to terminal REF-2.

[0345] The system 3300 further comprises, between terminal 476-2 of the device 400-2, and terminal REF-2 of the device 400-2, a capacitor C3305. A first terminal of the capacitor C3305 is connected, preferably connected, to terminal 476-2, and a second terminal of the capacitor C3305 is connected, preferably connected, to terminal REF-2. The capacitor C3305 makes it possible to bias the output voltage of the driving circuit of the device 400-2.

[0346] The system 3300 further and optionally comprises, between terminal 476-2 of the device 400-2, and terminal REF-2 of the device 400-2, a resistor R3303 and a capacitor C3306. A first terminal of the resistor R3303 is connected, preferably connected, to terminal 476-2, and a second terminal of the resistor R3303 is connected, preferably connected, to a first terminal of the capacitor C3306. A second terminal of the capacitor C3306 is connected, preferably connected, to terminal REF-2.

[0347] The system further comprises, between terminal 476-2 of device 400-2 and terminals 474-2 and 473-2 of device 400-2, a resistor R3304. A first terminal of resistor R3304 is connected, preferably connected, to terminal 476-2, and a second terminal of resistor R3304 is connected, preferably connected, to terminals 474-2 and 473-2. Resistor R3304 is a pull-up resistor making it possible to create a NOR type logic function taking as input the output voltages of terminals 474-2 and 473-2.

[0348] The operation of the system 3300 is described in relation to [Fig.35].

[0349] [Fig. 35] illustrates voltage and current timing diagrams of the 3300 system described in connection with [Fig. 34]. [Fig. 35] includes the following timing diagrams: - the timing diagram of the output voltage VOUT3300; - the timing diagram of the control voltage V(IN-l) received by terminal 475-1; - the timing diagram of the control voltage V(IN-2) received by terminal 475-2; - the timing diagram of the output current I(OUT); and - the timing diagram of the current I(L3301) passing through the diode L3201.

[0350] The control voltages V(IN-1) and V(IN-2) are square wave voltages oscillating between a high state and a low state. The output voltage VOUT3300 is also a square wave voltage whose maximum voltage gradually stabilizes. More particularly, at the start-up of the system 3300, not all the voltage regulator circuits are di operational. The output voltage VOUT3300 and the output current I(OUT) therefore have a pseudoperiodic appearance while all the voltage regulator circuits start up, then each stabilizes into a square wave signal alternating between a high state and a low state.

[0351] [Fig. 36] shows, schematically and partially in block form, a third embodiment of an application of the device 400. In [Fig. 36], the device 400 is shown in block form in the same way as in [Fig. 4]. All the variants of the circuits of the device 400 described in relation to FIGS. 5 to 31 are applicable here.

[0352] In [Fig.36], the device 400 is used in an electronic system 3400 to form a voltage converter circuit adapted to convert a DC input voltage VIN3200 into a DC output voltage VOUT3400. According to one example, the voltage VIN3400 is of the order of 220 V or 311 V. According to one example, the voltage VOUT3200 is of the order of 400 V.

[0353] The system 3400 comprises the device 400. The device 400 comprises, in this embodiment, an additional power supply terminal 3401 (SUPPLY). The terminal 3401 is connected, preferably connected, to a node IN3400 receiving the input voltage VIN3400.

[0354] The system 3400 further comprises an input capacitor C3401 disposed between the input node IN2300 and a reference node REF3400. Thus, a first terminal of the capacitor C3401 is connected, preferably to the node IN2300, and a second terminal of the capacitor C3401 is connected, preferably to the reference node REF3400.

[0355] The system 3400 further comprises, between the input node IN2300 and the drain terminal 470 (DRAIN) of the device 400, an output coil L3401. A first terminal of the coil L3401 is connected, preferably connected, to the node IN3400, and a second terminal of the coil 3401 is connected, preferably connected, to the terminal 470 of the device 400. The coil L3401 forms a first winding of a transformer providing the output voltage VOUT3400 of the system 3400.

[0356] The system 3400 further comprises a second part of the transformer of which the coil L3401 is a part. This part comprises a coil L3402, forming a second winding of the transformer, a diode D3401 and a capacitor C3402. A first terminal of the coil L3402 is connected, preferably connected, to the anode of the diode D3401, and the cathode of the diode D3401 is connected, preferably connected, to a node OUT3400 providing the output voltage VOUT3400. A second terminal of the coil L3402 is connected, preferably connected to a first terminal of the capacitor C3402, and a second terminal of the capacitor C3402 is connected, preferably connected to the node C3402.

[0357] The system 3400 further comprises a third part of the transformer, which includes the coils L3401 and L3402. This part comprises a coil L3403, forming a third winding of the transformer, a diode D3402 and a capacitor C3403. A first terminal of the coil L3403 is connected, preferably connected, to the anode of the diode D3402, and the cathode of the diode D3402 is connected, preferably connected, to the terminal 478 of the device 400. A second terminal of the coil L3403 is connected, preferably connected to a first terminal of the capacitor C3403, and a second terminal of the capacitor C3403 is connected, preferably connected to the terminal 478.

[0358] The system 3400 further comprises, between terminal 477 (DZ) and reference terminal 472 of the device 400, a Zener diode D3403. The cathode of the Zener diode 3403 is connected, preferably connected, to terminal 477, and the anode of the Zener diode D3403 is connected, preferably connected, to terminal 472. The diode D3403 may represent the external diode used in the voltage regulator and high voltage circuits of the device 400.

[0359] The system 3400 further comprises, between terminal 476 (VDD) and the reference terminal 472 of the device 400, a filter capacitor C3404. A first terminal of the capacitor C3404 is connected, preferably connected, to terminal 476, and a second terminal of the capacitor C3404 is connected, preferably connected to terminal 472.

[0360] The system 3400 further and optionally comprises, between terminal 476 (VDD) and reference terminal 472 of the device 400, a resistor R3401 and a capacitor C3405. A first terminal of the resistor R3401 is connected, preferably connected, to terminal 476, and a second terminal of the resistor R3401 is connected, preferably connected, to a first terminal of the capacitor C3405. A second terminal of the capacitor C3405 is connected, preferably connected, to terminal 472.

[0361] The operation of the 3400 system is as follows. At startup of the 3400 system, only terminal 3401 powers the system, but once the voltage regulators are started, terminals 3401 and 478 power the system, and the output voltage VOUT3400 stabilizes in the same manner as for the 3200 and 3400 systems.

[0362] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art.

[0363] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

Claims

1. A circuit for driving a first e-mode type HEMT power transistor (401) adapted to receive a maximum voltage of 650 V between its drain and its source, said circuit being formed in and on a monolithic semiconductor substrate (101) having a face covered with a layer of Gallium Nitride (102), and comprising at least one second e-mode type transistor (T2205) adapted to directly transmit a control voltage to the gate of the first transistor (401) and whose area is greater than 5 mm2, in which said second transistor (T2205) has its drain region in direct contact with the gate region of the first power transistor (401), and is placed as close as possible to said first transistor (401).

2. The circuit of claim 1, wherein said second transistor (T2205) has an area of between 10 and 15 mm2.

3. A circuit according to claim 1 or 2, wherein said second transistor (T2205) is composed of an assembly of several e-mode type transistors.

4. A device (400) comprising said first power transistor (401) and a driving circuit according to any one of claims 1 to 3.

5. The device of claim 4, wherein the second transistor (T2205) of the driving circuit comprises a drain region in direct contact with a gate region of the first power transistor (401).

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