Electrostatic discharge protection device

Abstract

Embodiments of the present disclosure relate to electrostatic discharge protection devices. The present specification relates to an electrostatic discharge protection apparatus comprising a first clipping circuit coupled between a first node and a second node and a second active clipping circuit coupled in series with a first resistor, the second clipping circuit and the first resistor being coupled between the first and second nodes, the second clipping circuit comprising a field effect transistor having a metal-oxide-semiconductor structure.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of French patent application No. 2100868, filed on January 29, 2021, which is incorporated herein by reference. Technical Field

[0003] This disclosure relates generally to electronic devices, and more specifically to electronic devices for protection against electrostatic discharge. Background Technology

[0004] Different devices are known for protecting against and preventing electrostatic discharge or ESD. Summary of the Invention

[0005] There is a need to improve the performance of existing electrostatic discharge (ESD) protection devices.

[0006] One embodiment provides an electrostatic discharge protection device including a first limiting circuit coupled between a first node and a second node and a second active limiting circuit coupled in series with a first resistor, the second limiting circuit and the first resistor being coupled between the first node and the second node, the second limiting circuit including a field-effect transistor having a metal-oxide-semiconductor structure.

[0007] According to an embodiment, the second circuit and the first resistor are coupled to each other through a third node, which is the output node of the device.

[0008] According to an embodiment, the field-effect transistor having a metal-oxide-semiconductor structure is an N-channel transistor.

[0009] According to one embodiment, the second limiting circuit has an on-resistance of less than 1 ohm.

[0010] According to one embodiment, the first resistor has a value of less than 100 ohms.

[0011] According to one embodiment, the first limiting circuit includes a bipolar transistor.

[0012] According to one embodiment, the bipolar transistor is an NPN transistor.

[0013] According to an embodiment, the first limiting circuit includes a second resistor coupled between the control terminal of the bipolar transistor and the second node.

[0014] According to one embodiment, the second resistor has a value of less than 1 ohm.

[0015] According to one embodiment, the limiting threshold of the first limiting circuit is higher than the limiting threshold of the second limiting circuit.

[0016] Another embodiment provides an electronic circuit that includes at least one device as described above.

[0017] According to one embodiment, at least two protection devices share the same circuit.

[0018] According to an embodiment, the third node is coupled to the terminal of the second limiting circuit via a diode.

[0019] According to one embodiment, a third output node of one of the devices is coupled to two second circuits, and one device shares the circuit with at least one other device. Attached Figure Description

[0020] The foregoing features and advantages, as well as other features and advantages, will be set forth in the following detailed description of embodiments by way of illustration rather than limitation, with reference to the accompanying drawings, in which:

[0021] Figure 1 An embodiment of an ESD protection device is shown;

[0022] Figure 2 It shows Figure 1 The equivalent circuit of the embodiment;

[0023] Figure 3 It shows Figure 1 Application examples of the embodiments; and

[0024] Figure 4 It shows Figure 1 Another example of the application of the embodiments. Detailed Implementation

[0025] In the various figures, the same features are indicated by the same reference numerals. In particular, common structural and / or functional features in the various embodiments may have the same reference numerals and may have the same structure, dimensions, and material properties.

[0026] For clarity, only the steps and elements useful for understanding the embodiments described herein are shown and described in detail.

[0027] Unless otherwise stated, when referring to two elements connected together, it means that there is no direct connection between them except for the conductor, and when referring to two elements connected together, it means that the two elements can be connected or they can be coupled through one or more other elements.

[0028] In the following disclosure, unless otherwise stated, when referring to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or when referring to relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or when referring to orientation qualifiers, such as "horizontal", "vertical", etc., the orientation shown in the figure is used.

[0029] Unless otherwise stated, the expressions “about,” “approximately,” “basically,” and “on the order of…” indicate within 10%, preferably within 5%.

[0030] Figure 1 An embodiment of ESD protection device 10 is shown. Device 10 is located between two nodes 12 and 14 and a rail or node 18 to which a reference voltage (preferably grounded GND) is applied. Device 10 protects a circuit (not shown) from electrostatic discharge. The performance of device 10 in relation to this protection is measured according to various standards, including the so-called human body model standard.

[0031] Voltage V1 is applied to node 12, and voltage V2 is applied to node 14. Device 10 is located in an electronic circuit to protect circuit components coupled to one side of node 14 from discharges, for example, occurring at node 12, or to protect components or connectors coupled to one side of node 12 from discharges, for example, occurring at node 14.

[0032] Device 10 includes a first limiting circuit 16. Circuit 16 is coupled (preferably connected) between node 12 and node 18. In other words, one end of circuit 16 is coupled (preferably connected) to node 12, and the other end of circuit 16 is coupled (preferably connected) to node 18.

[0033] Device 10 includes a second limiting circuit 20 coupled (preferably connected) between nodes 14 and 18. In other words, one end of circuit 20 is coupled (preferably connected) to node 14, and the other end of circuit 20 is coupled (preferably connected) to node 18. Device 20 is an active device, meaning that device 20 includes at least one active element. Device 10 also includes a resistor 22 coupled between nodes 12 and 14. In other words, one terminal of resistor 22 is coupled (preferably connected) to node 12, and the other end of resistor 22 is coupled (preferably connected) to node 14.

[0034] A limiting circuit is a circuit designed to suppress overvoltage; it consists of two terminals and can be in an on or off state. When the circuit is on, current can flow between the two terminals. When the circuit is off, current cannot flow between the two terminals. The state of the limiting circuit depends on the voltage between the two terminals. Therefore, if the voltage between the two terminals is less than the limiting threshold, the circuit is off. If the voltage between the two terminals is greater than the limiting threshold, the circuit is on.

[0035] Preferably, one of the two terminals is coupled (preferably connected) to the node where the reference voltage is applied, such as ground. In this case, the state of the limiting circuit depends on the voltage at the other terminal. Therefore, if the voltage at the other terminal is less than the limiting threshold, the circuit is in the off state. If the voltage at the other terminal is greater than the limiting threshold, the circuit is in the on state. When the voltage at the other node reaches the threshold, for example during electrostatic discharge, energy (more precisely, current) can be discharged into ground.

[0036] Circuit 16 is a limiting circuit with a limiting threshold greater than that of circuit 20. For example, circuit 16 has a limiting threshold that is more than twice that of circuit 20. For example, circuit 16 has a limiting threshold greater than 5V, such as approximately 7.5V. For example, circuit 20 has a threshold less than 5V, such as approximately 2.5V.

[0037] Furthermore, circuit 16 is configured, for example, to withstand a current of at least 3A. In other words, circuit 16 is configured, for example, such that a current of at least 3A can pass through it without damaging it. More generally, circuit 16 is configured, for example, to withstand an instantaneous discharge current of several amperes. According to human body model standards, an instantaneous current in amperes is on the order of Vzap / 1500, where Vzap is the discharge voltage in volts.

[0038] Circuit 16 includes, for example, a transistor 24. Transistor 24 is preferably a bipolar transistor, such as an NPN transistor. Transistor 24 is coupled (preferably connected) between nodes 12 and 18. Preferably, a conductive terminal of transistor 24, preferably the collector of transistor 24, is coupled (preferably connected) to node 12, and another conductive terminal of transistor 24, preferably the emitter of transistor 24, is coupled (preferably connected) to node 18. Circuit 16 includes, for example, a resistor 26 coupled between the control terminal (e.g., base) of transistor 24 and node 18. In other words, a terminal of resistor 26 is coupled (preferably connected) to the base of transistor 24, and the other terminal of resistor 26 is coupled (preferably connected) to node 18. Preferably, circuit 16 includes a diode, whose cathode is coupled (preferably connected) to node 12, and whose anode is coupled (preferably connected) to node 18. The diode is, for example, an intrinsic diode of transistor 24.

[0039] Circuit 20 includes a metal-oxide-semiconductor field-effect transistor 28 or a MOSFET transistor. Circuit 20 may include only transistor 28, for example. Transistor 28 is preferably an N-channel MOSFET transistor. The transistor is coupled (preferably connected) between node 14 and node 18. In other words, a conductive terminal (e.g., drain) of transistor 28 is coupled (preferably connected) to node 14, and another conductive terminal (e.g., source) of transistor 28 is coupled (preferably connected) to node 18. Transistor 28 is a controlled transistor, i.e., a transistor having a potential at its gate controlled by a circuit (not shown, e.g., circuitry outside of circuit 10) such that, in the event of a positive overvoltage detected between node 12 and node 18, the gate potential increases to turn transistor 28 on. In other words, the gate of transistor 28 is not controlled by a fixed or constant potential during operation of device 10. The gate of transistor 28 is not coupled to any node having a fixed or constant potential thereon during operation of device 10.

[0040] During positive discharge, for example at node 12, most of the discharge energy is transferred through circuit 16, which conducts current between node 12 and node 18 (e.g., ground). For example, if transistor 24 is an NPN transistor, it operates in collector-emitter breakdown mode. However, at the level of circuit 16, i.e., the potential at node 12, remains too high because the limiting threshold cannot be reduced without problematicly increasing the surface area of ​​the circuit. Circuit 20 reduces this potential to a value that does not risk damaging the device coupled to node 14. The energy transferred through circuit 20 is significantly less than the energy transferred through circuit 16.

[0041] During negative discharge, the discharge passes through circuit 16, and more specifically, through the diodes in circuit 16.

[0042] Figure 2 It shows Figure 1 The equivalent circuit during discharge in the embodiment. In particular, Figure 2 This illustrates the situation when the current peak occurs on one side of node 12, i.e., when the limiting circuit is on. Figure 1 The equivalent circuit of device 10.

[0043] The equivalent circuit includes and Figure 1 The same components as those in device 10 will not be described in detail again.

[0044] Equivalent circuit and Figure 1 The difference between the devices is that each limiting circuit 16, 20 is replaced by an equivalent circuit, that is, a circuit with the same characteristics, preferably the same characteristics. More precisely, each limiter is replaced by a resistor and a voltage source connected in series, the resistor corresponding to the on-state resistance, and the value of the voltage source corresponding to the threshold of the limiting circuit.

[0045] Therefore, in the equivalent representation, circuit 16 includes a resistor 30 connected in series with a voltage source 32 between nodes 12 and 18. In other words, circuit 16 is represented as a circuit including a source 32 coupled (preferably connected) to node 18 via a first terminal and coupled (preferably connected) to the first terminal of resistor 30 via a second terminal, the second terminal of resistor 30 being coupled (preferably connected) to node 12. Circuit 16 is selected, for example, to have an on-state resistance of less than 5 ohms, preferably less than 1 ohm, for example less than 500 milliohms, for example substantially equal to 100 milliohms. Circuit 16 is selected, for example, to have a limiting threshold corresponding to the voltage value delivered by the voltage source 32 in the equivalent circuit, which is greater than 5V, for example substantially equal to 7.5V.

[0046] Similarly, in the equivalent representation, circuit 20 therefore includes a resistor 34 connected in series with a voltage source 36 between nodes 14 and 18. In other words, circuit 20 behaves as a circuit including a source 36 coupled (preferably connected) to node 18 via a first terminal and coupled (preferably connected) to the first terminal of resistor 34 via a second terminal, the second terminal of resistor 34 coupled (preferably connected) to node 14. Circuit 20 is selected, for example, to have an on-state resistance of less than 5 ohms, preferably less than 1 ohm, for example, substantially equal to 1 ohm. Circuit 20 is selected, for example, to have a limiting threshold corresponding to the voltage value delivered by the voltage source 36 in the equivalent circuit, which is greater than 5V, for example, substantially equal to 2.5V.

[0047] When, for example, a current peak occurs at node 12, circuit 16 enters the ON state, and some energy is discharged to ground via circuit 16. Similarly, circuit 20 enters the ON state. Then, the device... Figure 2 It works like an equivalent circuit.

[0048] Resistors 22 and 34 form a voltage divider that provides a lower voltage at node 14 than at node 12. Therefore, the limiting circuit 20 does not need to be configured to withstand the same voltage and current as in circuit 16.

[0049] The limiting voltage of device 10 depends on the inherent threshold values ​​of limiting circuits 16 and 20, as well as the value of the resistor in device 10. The limiting voltage of device 10 is less than the threshold value of circuit 16, i.e., the threshold value of the limiting circuit located on the node 12 side. The limiting voltage of device 10 is greater than the threshold value of circuit 20, i.e., the threshold value of the limiting circuit located on the node 14 side.

[0050] The limiting voltage of device 10 during discharge is determined by the following equation:

[0051] [Mathematical Expression 1]

[0052]

[0053] Where VOUT is the limiting threshold value of device 10, and S2 is the threshold value of device 20, i.e., voltage source 36 ( Figure 2 The value of R2 is the on-state resistance of device 20, i.e., resistor 34. Figure 2 The value of ), and R3 is the value of resistor 22.

[0054] Resistor 22 preferably has a relatively low value to avoid excessive energy loss in normal operating mode, i.e., when the limiting circuit is off, in other words, when the circuitry inside the product, coupled to node 14, bypasses a considerable current (typically toward ground potential) during normal operation of the product. A significant voltage drop would interfere with circuit operation. Preferably, resistor 22 has a value of less than 100 ohms, preferably in the range of 10 to 30 ohms, and preferably substantially equal to 20 ohms.

[0055] As a variant, transistor 24 and resistor 26 can be replaced by another limiting circuit that can withstand a current greater than 3A and has an on-resistance of less than 5 ohms, preferably less than 1 ohm, for example less than 500 microohms, for example substantially equal to 100 microohms, and a limiting threshold greater than the threshold of circuit 20, for example greater than 5V, for example substantially equal to 7.5V.

[0056] Alternatively, a limiting circuit such as circuit 16 can be used. However, this limiting circuit cannot achieve a sufficiently low limiting threshold. The limiting threshold of this circuit is greater than 5V, typically greater than 7V. This circuit is not suitable for protecting components that can be damaged by voltages on the order of 3V or less.

[0057] A limiting circuit such as circuit 20 can be used. However, the energy that can be released to ground by such a circuit depends on the size of transistor 28. In order to withstand such high current peaks while having a relatively low limiting threshold, i.e., for example, below 5V, the size of transistor 28 should be significant, for example, a channel width greater than 1000μm, or even greater than 10000μm, which results in a large loss of surface area. Furthermore, such a transistor includes significant leakage, which adversely affects the performance of the product, particularly by increasing its idle power consumption.

[0058] The advantages of the foregoing embodiments are that they enable the formation of ESD protection devices capable of withstanding significant current peaks while possessing low limiting thresholds. Furthermore, the surface area of ​​the ESD protection device is advantageously small, particularly compared to devices comprising only transistor 28, because... Figure 1 In this embodiment, transistor 28 must only withstand a small fraction of the current generated during the current peak.

[0059] Another advantage of the embodiment is that it has lower leakage current compared to conventional protection devices, and especially compared to devices that only include limiting circuits such as circuit 20.

[0060] Figure 3 It shows Figure 1 Application examples of the embodiments. Figure 3 Electronic circuit 50 is shown.

[0061] Circuit 50 includes three terminals 52, 54, and 56, each indicated by a box. Terminal 52 corresponds, for example, to a clock input, i.e., an input that receives a clock signal or a write control signal. Terminal 54 corresponds to an input / output for receiving and transmitting data (e.g., binary data). Terminal 56 is, for example, a power supply terminal, i.e., an input that receives the power supply voltage of circuit 50. More generally, circuit 50 may have any number of terminals.

[0062] Circuit 50 preferably includes ESD protection devices, which have similar characteristics to each terminal. Figure 1 The operation of the device. Therefore, in Figure 3 In the example, device 50 includes three devices 10a, 10b, and 10c. Terminal 52 is coupled to (preferably connected to) device 10a, terminal 54 is coupled to (preferably connected to) device 10b, and terminal 56 is coupled to (preferably connected to) device 10c. Preferably, at least some of the devices 10 share the same circuit 20. Figure 3 In the example, all circuits 10 share the same circuit 20.

[0063] More precisely, device 10a includes circuit 16a, resistor 22a, and circuit 20. Circuit 16a is coupled (preferably connected) between terminal 52 and node 18. Circuit 16a includes transistor 24a and resistor 26a. Figure 1 Similar to transistor 24, transistor 24a is preferably a bipolar transistor, such as an NPN transistor. Transistor 24a is coupled (preferably connected) between terminal 52 and node 18. Preferably, the conductive terminal of transistor 24a, preferably the collector terminal of transistor 24a, is coupled (preferably connected) to terminal 52, and the other conductive terminal of transistor 24a, preferably the emitter terminal of transistor 24a, is coupled (preferably connected) to node 18. Resistor 26a is preferably coupled between the control terminal (e.g., base) of transistor 24a and node 18. In other words, one end of resistor 26a is coupled (preferably connected) to the base of transistor 24a, while the other end of resistor 26a is coupled (preferably connected) to node 18.

[0064] Resistor 22a of circuit 10a is coupled (preferably connected) between terminal 52 and output node 14a of device 10a. In other words, one terminal of resistor 22a is coupled (preferably connected) to terminal 52, and the other terminal of resistor 22a is coupled (preferably connected) to node 14a.

[0065] Node 14a is coupled, for example, to other components of circuit 50 protected by circuit 10. Node 14a is also coupled to terminals of circuit 20 shared by device 10. Node 14a is preferably coupled to terminals of circuit 20 via diode 62a. The cathode of diode 62a is coupled (preferably connected) to node 60 corresponding to a terminal of circuit 20. The anode of diode 62a is coupled (preferably connected) to node 14a.

[0066] Similarly, device 10b includes resistor 22b, transistor 24b, resistor 26b, circuit 20, and diode 62b coupled in the same manner. Thus, resistor 22b is coupled between terminal 54 and output node 14b of device 10b. Transistor 24b is coupled between terminal 54 and node 18 via its conductive terminal. Resistor 26b is coupled between the control terminal (i.e., the base of transistor 24b) and node 18. Node 14b is coupled to node 60 via diode 62b. The anode of diode 62b is coupled (preferably connected) to node 14b, while the cathode of diode 62b is coupled (preferably connected) to a terminal of circuit 20.

[0067] Terminal 54 is coupled (preferably connected) to node 60, for example, via diode 64. The anode of diode 64 is coupled (preferably connected) to terminal 54, and the cathode of diode 64 is coupled (preferably connected) to node 60. Therefore, diode 64 is coupled in parallel with diode 62b and resistor 22b. Diode 64 is able to protect terminal 54 from overvoltage.

[0068] Terminal, i.e. Figure 3 Terminal 54 in the example can be coupled to node 18, for example, via a resistor assembly 66 having a variable total resistance. Assembly 66 includes, for example, a series connection of resistors R1, R2, RN and multiple series connections of switches Int1, Int2, Intn (e.g., transistors, such as N-channel MOS transistors). In each connection, one terminal of the resistor is coupled (preferably connected) to terminal 54, another terminal of the resistor is coupled (preferably connected) to one terminal of the switch, and another terminal of the switch is coupled (preferably connected) to node 18. The switches are controlled by circuit 68. Circuit 68 is coupled (preferably connected) to the control terminals of switches Int1, Int2, Intn. Circuit 68 provides switch control signals.

[0069] Similarly, device 10c includes resistor 22c, transistor 24c, resistor 26c, and circuit 20 coupled in the same manner. Thus, the resistor is coupled between terminal 56 and output node 14c of device 10c. Transistor 24c is coupled between terminal 56 and node 18 via its conductive terminal. Resistor 26c is coupled between the control terminal (i.e., base) of transistor 24c and node 18. Node 14c is coupled (preferably connected) to node 60. Preferably, node 14c, i.e., the output node of device 10c coupled to the power supply terminal, is not coupled to node 60 via a diode.

[0070] The presence of diode 62 advantageously enables device 10 to have a common circuit 20. In effect, the presence of a current peak at one terminal changes the voltage at node 14c, but does not affect other nodes 14. In other words, diodes 62a and 62b enable circuit 20 (in...) Figure 3 The part shown as part of device 10c is shared by device 10a or 10b (input or input / output). Therefore, device 10a forms a structure such as Figure 1 The device of the device, among which Figure 1 Circuit 20 was Figure 3 Diode 62a and circuit 20 are replaced. Similarly, in the case of device 10b, Figure 1 Circuit 20 was Figure 3Diode 62b and circuit 20 are replaced. Diodes 62a and 62b also prevent electrical interference between devices 10a, 10b and 10c during normal operation, during which the maximum voltage at the input of devices 10a, 10b and 10c is less than or equal to the supply voltage of the load coupled to node 60.

[0071] For example, at least some of the devices 10 (e.g., all of the devices 10) are identical, namely resistors 22a, 22b, 22c, transistors 24a, 24b, 24c, and resistors 26a, 26b, 26c are identical to each other. Similarly, diodes 62a and 62b are, for example, identical to each other. As a variation, at least some of the devices 10 may have different characteristics.

[0072] Figure 4 It shows Figure 1 Another example of the application of the embodiments. Figure 4 Electronic circuit 70 is shown.

[0073] Circuit 70 includes the same components as circuit 50. In particular, circuit 70 includes terminals 52, 54, and 56. In addition, circuit 70 includes devices 10a, 10b, and 10c.

[0074] The difference between device 70 and device 50 is particularly evident in devices 10a and 10b, and in device 10c, which includes different circuits 20.

[0075] More precisely, device 10a is coupled (preferably connected) to terminal 52. As previously described, device 10a includes circuit 16, resistor 22a, and diode 62a. Circuit 16a is coupled (preferably connected) between terminal 52 and node 18. Circuit 16a includes transistor 24a and resistor 26a. Transistor 24a is preferably a bipolar transistor, such as an NPN transistor. Transistor 24a is coupled (preferably connected) between terminal 52 and node 18. Preferably, the conductive terminal of transistor 24a, preferably the collector of transistor 24a, is coupled (preferably connected) to terminal 52, and another conductive terminal of transistor 24a, preferably the emitter of transistor 24a, is coupled (preferably connected) to node 18. Resistor 26a is preferably coupled between the control terminal (e.g., base) of transistor 24a and node 18. In other words, one end of resistor 26a is coupled (preferably connected) to the base of transistor 24a, while the other end of resistor 26a is coupled (preferably connected) to node 18.

[0076] Resistor 22a of circuit 10a is coupled (preferably connected) between terminal 52 and output node 14a of device 10a. In other words, one end of resistor 22a is coupled (preferably connected) to terminal 52, and the other end of resistor 22a is coupled (preferably connected) to node 14a.

[0077] Node 14a is coupled, for example, to other components of circuit 70 protected by circuit 10. Node 14a is also coupled to a terminal of circuit 20-1 shared by devices 10a and 10b. Node 14a is preferably coupled to a terminal of circuit 20-1 via diode 62a. The cathode of diode 62a is coupled (preferably connected) to node 76. The anode of diode 62a is coupled (preferably connected) to node 14a. Another terminal of circuit 20-1 is coupled (preferably connected) to node 18.

[0078] Device 10b includes a transistor 24b, resistors 26b and 22b, and a diode 62b, which are element-coupled similarly to those in device 10a. The cathode of diode 62b is therefore coupled (preferably connected) to node 76.

[0079] Terminal 54 is coupled to the aforementioned resistive element 66, for example, via resistor 80. More specifically, one terminal of resistor 80 is coupled to (preferably connected to) terminal 54, and the other terminal of resistor 80 is coupled to (preferably connected to) node 74. Node 74 is preferably coupled to node 76 corresponding to the terminal of circuit 20-1 via diode 78. The cathode of diode 78 is coupled to (preferably connected to) node 76, and the anode of diode 78 is coupled to (preferably connected to) node 74.

[0080] Terminal 56 is coupled to device 10c. Device 10c includes transistor 24c and resistors 22c and 26c, respectively coupled together, just as transistor 24a and resistors 22a and 26a. Output node 14c of device 10c is coupled to node 76 via diode 82. More precisely, the cathode of diode 82 is coupled (preferably connected) to node 76, while the anode of diode 82 is coupled (preferably connected) to node 14c. Furthermore, node 14c is coupled (preferably connected) to one end of circuit 20-2, and the other end of circuit 20-2 is coupled (preferably connected) to node 18.

[0081] Device 10c, i.e., an ESD protection device coupled to one of its terminals (preferably, a power terminal), includes two circuits, for example... Figure 1 Circuit 20. Preferably, the limiting threshold of circuit 20-2 is lower than the threshold of circuit 20-1.

[0082] Figure 4The embodiment enables device 70 to withstand voltages at terminals 52 and 54 of devices 10a and 10b that are higher than the supply voltage. Diode 82 prevents current from returning from node 76 to the supply voltage, i.e., node 14c. This is advantageous in the case of circuits operating via an inter-integrated circuit (I2C) serial bus, where the voltages at the levels of line serial data (SDA) (e.g., terminal 54) and / or serial clock (SCL) (e.g., terminal 52) may be higher than the circuit's supply voltage. Diode 82 charges the voltage at node 76 to the potential value of terminal 56, i.e., the terminal where the supply voltage is supplied, minus the threshold voltage of voltage 82 (typically 600mV), while preventing current 76 from returning to the supply voltage. The charge at node 76 increases the input impedance of terminals 52 and 54 by shielding leakage current and the parasitic capacitance of circuit 20-1.

[0083] Figure 3 and Figure 4 The advantage of these embodiments is that they can reduce the number of surface-dense circuits 20.

[0084] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations can be combined, and other variations will occur to those skilled in the art.

[0085] Finally, based on the functional indications given above, the actual implementation of the described embodiments and variations is within the capabilities of those skilled in the art.

Claims

1. An electrostatic discharge protection device, comprising: A plurality of first limiting circuits, each of the plurality of first limiting circuits comprising: A bipolar transistor having a first conductive path coupled between a first node and a common second node; A second resistor is coupled between the control terminal of the bipolar transistor and the common second node, wherein the second resistor is separated from the bipolar transistor; A plurality of first resistors, each of the plurality of first resistors being coupled between a corresponding first node and a corresponding third node in the first node; A second active limiting circuit, shared by each of the plurality of first limiting circuits, and including a metal-oxide-semiconductor field-effect transistor having a second conduction path coupled between each third node and the common second node; and A plurality of protected devices, each of the plurality of protected devices being coupled to a corresponding third node in the third node, and wherein each of the corresponding third nodes is coupled to the second active limiting circuit via a corresponding diode.

2. The device of claim 1, wherein each of the third nodes is an output node of the corresponding first resistor and the associated first limiting circuit.

3. The device according to claim 1, wherein the metal-oxide-semiconductor field-effect transistor is an N-channel transistor.

4. The device of claim 1, wherein the second active limiting circuit has an on-state resistance of less than 1 ohm.

5. The device of claim 1, wherein the first resistor has a value of less than 100 ohms.

6. The device according to claim 1, wherein the bipolar transistor is an NPN transistor.

7. The device of claim 1, wherein the second resistor has a value of less than 1 ohm.

8. The device according to claim 1, wherein the first limiting threshold of the first limiting circuit is greater than the second limiting threshold of the second active limiting circuit.

9. An electronic circuit, comprising: A plurality of first limiting circuits, each of the plurality of first limiting circuits comprising: A bipolar transistor having a first conductive path coupled between a first node and a common second node; A second resistor is coupled between the control terminal of the bipolar transistor and the common second node, wherein the second resistor is separated from the bipolar transistor; A plurality of first resistors, each of the plurality of first resistors being coupled between a corresponding first node and a corresponding third node in the first node; The second active limiting circuit is shared by each of the plurality of first limiting circuits and includes a metal-oxide-semiconductor field-effect transistor having a second conduction path coupled between each third node and the common second node. Multiple protected devices, each protected device being coupled to a corresponding third node in the third node; At least one of the third nodes is coupled to a terminal of the second active limiting circuit via a corresponding diode; and The third node in the third node is directly connected to the terminal of the second active limiting circuit without having an intermediate diode.

10. The circuit of claim 9, wherein each of the third nodes is an output node of the corresponding first resistor and the associated first limiting circuit.

11. The circuit of claim 10, wherein at least two output nodes of the output node are coupled to terminals of the second active limiting circuit via corresponding diodes.

12. The circuit of claim 9, wherein the metal-oxide-semiconductor field-effect transistor is an N-channel transistor.

13. The circuit of claim 9, wherein the second active limiting circuit has an on-state resistance of less than 1 ohm.

14. The circuit of claim 9, wherein the first resistor has a value of less than 100 ohms.

15. The circuit of claim 9, wherein the corresponding first limiting threshold of each first limiting circuit is greater than the second limiting threshold of the second active limiting circuit.

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