Electric fuse storage unit and storage device

Abstract

The invention relates to an electric fuse memory cell and a memory device. In the electric fuse memory cell, a fuse element is coupled between a programming voltage node and the ground, a first switch element is coupled between a power supply voltage and the programming voltage node, and a negative feedback structure is configured to generate a negative feedback signal when the voltage of the programming voltage node is greater than the reference voltage. And when the voltage of the programming voltage node is smaller than the reference voltage, the turn-on degree of the first switching element is reduced so as to reduce the voltage of the programming voltage node, and when the voltage of the programming voltage node is smaller than the reference voltage, the turn-on degree of the first switching element is increased so as to increase the voltage of the programming voltage node. By means of the negative feedback structure, the voltage of the programming voltage node can be adjusted in a self-adaptive mode to be close to or equal to the reference voltage, it is ensured that the programming voltage is within the expected range, stable programming current can be formed easily, the programming process can be stably controlled conveniently, and the fusing yield is improved.

Description

Technical Field

[0001] The present invention relates to the field of storage technology, and in particular to an electric fuse storage unit and a storage device. Background Art

[0002] The eFuse is programmed by applying high-density current to metal strips or polysilicon strips, and can be used as a basic module in integrated circuits such as SoCs. The data in the storage device based on the eFuse is non-volatile when the power is off. It can be used to store chip identifiers (ID) such as serial numbers, can be used for analog circuit trimming to achieve fine-tuning of circuit parameters, can be used to store copyright protection keys to ensure the security of codes and documents, and can also be used to store key information such as security keys and passwords to ensure the security of chips.

[0003] In the commonly used electric fuse storage unit, a switch element is provided between the fuse element and the power supply voltage and / or between the fuse element and the ground. Each electric fuse storage unit can store one bit of binary data. The memory usually includes multiple electric fuse storage units with the same structure to achieve more complex data storage. The power supply voltage and switch element used by each electric fuse storage unit are the same. However, due to the manufacturing deviation of the switch element, combined with the change of temperature and voltage conditions, the voltage conditions required for each electric fuse storage unit when writing programming data are inconsistent, so that the actual programming voltage and programming current are very discretely distributed, resulting in the programming process cannot be stably controlled and the fuse yield (burning yield) is low. Summary of the invention

[0004] In order to stably control the programming process of an electric fuse storage unit and improve the fusing yield, the present invention provides an electric fuse storage unit and also provides a storage device.

[0005] In one aspect, the present invention provides an electric fuse storage unit, the electric fuse storage unit comprising: a fuse element having a first end and a second end, the first end being coupled to a programming voltage node, the second end being coupled to ground; A first switch element is coupled between a supply voltage and the programming voltage node; and A negative feedback structure is configured to reduce the opening degree of the first switch element to reduce the voltage of the programming voltage node when the voltage of the programming voltage node is greater than a reference voltage, and to increase the opening degree of the first switch element to increase the voltage of the programming voltage node when the voltage of the programming voltage node is less than the reference voltage.

[0006] Optionally, the negative feedback structure includes a negative feedback element, the negative feedback element is connected to the voltage of the programming voltage node and the reference voltage, and outputs a control signal for controlling the opening degree of the first switch element.

[0007] Optionally, the negative feedback element is a transconductance amplifier, a non-inverting input terminal of the transconductance amplifier is coupled to the programming voltage node, and an inverting input terminal of the transconductance amplifier is coupled to the reference voltage.

[0008] Optionally, the negative feedback element adopts an error operational amplifier, a non-inverting input terminal of the error operational amplifier is coupled to the programming voltage node, and an inverting input terminal of the error operational amplifier is coupled to the reference voltage.

[0009] Optionally, the first switch element is a PMOS transistor, a source terminal of the PMOS transistor is coupled to the supply voltage, and a drain terminal of the PMOS transistor is coupled to the programming voltage node.

[0010] Optionally, the electrical fuse storage unit further includes a second switch element coupled between the second end of the fuse element and ground.

[0011] Optionally, the second switch element is an NMOS transistor, a source terminal of the NMOS transistor is grounded, and a drain terminal of the NMOS transistor is coupled to the second terminal of the fuse element.

[0012] In another aspect, the present invention provides a storage device, comprising the above-mentioned electric fuse storage unit.

[0013] Optionally, the storage device comprises a plurality of the electric fuse storage units, and the first switch elements and the fuse elements in each of the electric fuse storage units are the same.

[0014] Optionally, the electrical fuse storage units use the same supply voltage and the same reference voltage.

[0015] In the electric fuse storage unit and storage device provided by the present invention, the fuse element is coupled between a programming voltage node and ground. When the voltage of the programming voltage node forms a programming voltage and a high-density current is formed between the programming voltage node and the ground, the fuse element can be blown within a preset time to achieve programming. The negative feedback structure can reduce the opening degree of the first switch element to reduce the voltage of the programming voltage node when the voltage of the programming voltage node is greater than the reference voltage, and increase the opening degree of the first switch element to increase the voltage of the programming voltage node when the voltage of the programming voltage node is less than the reference voltage. The negative feedback structure can be used to adaptively adjust the voltage of the programming voltage node to make it approach or equal to the reference voltage, thereby ensuring that the programming voltage is within the expected range, helping to form a stable programming current, facilitating stable control of the programming process, and improving the blown yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A circuit diagram of an electric fuse storage unit.

[0017] Figure 2 FIG. 4 is a circuit diagram of an electric fuse storage unit according to an embodiment of the present invention.

[0018] Figure 3 yes Figure 2 The diagram shows how the voltages of the power supply voltage, reference voltage and programming voltage node in the electric fuse memory cell vary with time. DETAILED DESCRIPTION

[0019] The following is a further detailed description of the electric fuse storage unit and storage device of the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will become clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In the specification, if "first" and "second" are used, they are used to distinguish between similar elements, and are not necessarily used to describe a specific order or time sequence. It should be understood that these terms used in this way are replaceable where appropriate. The "connection" or "coupling" mentioned below can be a direct connection, that is, the two components are connected together without passing through other components, or an indirect connection, that is, the two components are connected together through other components.

[0020] Figure 1 A circuit diagram of an electric fuse storage unit. Figure 1An electric fuse storage unit includes a fuse element F10, a first switch element P0 (for example, a PMOS transistor) and a second switch element N0 (for example, an NMOS transistor), wherein the first switch element P0 couples a power supply voltage Vdd to one end of the fuse element F10, and the second switch element N0 couples the other end of the fuse element F10 to the ground. A programming voltage node P is located between the fuse element F10 and the first switch element P0, and a voltage VP of the programming voltage node P is a voltage of an end of the fuse element F10 connected to the first switch element P0. When programming the electric fuse storage unit, the first switch element P0 and the second switch element N0 are turned on, and the voltage VP of the programming voltage node P is a programming voltage, which causes a high-density current (i.e., a programming current) to pass through the fuse element F10, thereby blowing the fuse element F10. After blowing, the resistance between the programming voltage node P and the ground increases, thereby realizing programming of the electric fuse storage unit.

[0021] Figure 1 One electric fuse storage unit shown can store one bit of binary data. By using a plurality of the electric fuse storage units, more complex data storage can be realized. When using a plurality of the electric fuse storage units for storage, the structures of the electric fuse storage units are, for example, the same, and the input signals (such as the power supply voltage Vdd, the turn-on signals of the first switch element P0 and the second switch element N0) used are the same. However, due to the manufacturing deviation of the switch element, combined with the changes in temperature and voltage conditions, the programming voltages (i.e., the voltage VP of the programming voltage node P) corresponding to each electric fuse storage unit during programming are not consistent, so that the actual programming voltage and programming current are very discretely distributed, resulting in the programming process cannot be stably controlled and the fuse yield is low.

[0022] The electric fuse storage unit of the embodiment of the present invention has a negative feedback structure, which can adaptively adjust the voltage VP of the programming voltage node P to make it close to or equal to the reference voltage, ensuring that the programming voltage is within the expected range during programming, thereby facilitating the stabilization of the programming current, thereby stably controlling the programming process and improving the fuse yield rate. The specific description is as follows.

[0023] Reference Figure 2 According to an embodiment of the present invention, the electric fuse storage unit includes a fuse element F10, a first switch element P0 and a negative feedback structure 100, and may further include a second switch element N0.

[0024] The fuse element F10 may be a metal strip or a polysilicon strip. The electric fuse storage unit is programmed by fusing the fuse element F10 under a suitable high-density current. In this embodiment, one end (referred to as the first end) of the fuse element F10 is coupled to the programming voltage node P, and the other end (referred to as the second end) is coupled to the ground. The voltage of the programming voltage node P is represented as VP. During programming, the voltage VP of the programming voltage node P is the programming voltage applied to the fuse element F10.

[0025] The first switch element P0 is coupled between the power supply voltage Vdd and the programming voltage node P. Figure 2 As shown, the first switch element P0 is, for example, a PMOS transistor, the source end of the PMOS transistor is coupled to the power supply voltage Vdd, and the drain end is coupled to the programming voltage node P. In another embodiment, the first switch element P0 may also be a JFET (junction field effect transistor), a BJT (bipolar junction transistor) or other suitable switch elements. In this embodiment, the first switch element P0 is used to control the transfer of the power supply voltage Vdd to the programming voltage node P, and because the first switch element P0 has an on-resistance, a voltage division is formed when the power supply voltage Vdd is transferred to the programming voltage node P, so that the voltage VP of the programming voltage node P is less than the power supply voltage Vdd. In this embodiment, the PMOS transistor, for example, operates in a saturation region.

[0026] The second switch element N0 is coupled between the second end of the fuse element F10 and the ground. Figure 2 As shown, the second switch element N0 is, for example, an NMOS transistor, the source end of the NMOS transistor is grounded, and the drain end is coupled to the second end of the fuse element F10. In another embodiment, the second switch element N0 may also be a JFET (junction field effect transistor), a BJT (bipolar junction transistor) or other suitable switch elements. In this embodiment, the second switch element N0 is used to receive a selection signal for the corresponding electrical fuse storage unit. When the selection signal is received, the second switch element N0 is turned on. When the first switch element P0 is also turned on under the corresponding control signal, the electrical fuse storage unit can be programmed.

[0027] The negative feedback structure 100 is configured to reduce the opening degree of the first switch element P0 to reduce the voltage VP of the programming voltage node P when the voltage VP of the programming voltage node P is greater than the reference voltage Vref, and to increase the opening degree of the first switch element P0 to increase the voltage VP of the programming voltage node P when the voltage VP of the programming voltage node P is less than the reference voltage Vref.

[0028] In this embodiment, the first switch element P0 is a PMOS transistor. When the absolute value of the gate-source voltage (|VGS|) of the PMOS transistor is greater than the threshold voltage (Vth), the PMOS transistor is turned on, and a corresponding current is formed between its drain terminal and source terminal (or programming voltage node P). According to the output characteristic curve of the PMOS transistor, when |VGS| decreases, the opening degree of the PMOS transistor decreases, and the on-resistance between its drain terminal and source terminal increases, then the voltage division of the PMOS transistor increases, so that the voltage VP formed at the programming voltage node P after the power supply voltage Vdd passes through the PMOS transistor decreases. That is, by changing the opening degree of the first switch element P0, the voltage division of the first switch element P0 can be changed, and then the voltage VP of the programming voltage node P can be changed. When programming is performed, the increase of VP will increase the current flowing through the fuse element F10, that is, the programming current. In this embodiment, the negative feedback structure 100 changes the opening degree of the first switch element P0 according to the comparison result between the voltage VP of the programming voltage node P and the reference voltage Vref, so that the voltage of the programming voltage node P approaches or is equal to the reference voltage Vref, thereby realizing negative feedback.

[0029] The reference voltage Vref can be set as needed. For example, different reference voltages Vref can be set as needed to turn off or on the first switch element P0, and a reference voltage Vref of corresponding size can be set according to the voltage VP of the programming voltage node P to be obtained to adjust the degree of opening of the first switch element P0.

[0030] The negative feedback structure 100 may include various circuits and elements that can realize the above functions. As an example, the negative feedback structure 100 includes a negative feedback element, which is connected to the voltage VP of the programming voltage node P and the reference voltage Vref, and outputs a control signal for controlling the opening degree of the first switch element P0. In one embodiment, Figure 2 As shown, the negative feedback element adopts a transconductance amplifier OTA, the positive power supply terminal and the negative power supply terminal of the transconductance amplifier OTA are respectively connected to the power supply voltage Vdd and the ground, and the non-inverting input terminal of the transconductance amplifier OTA is coupled to the programming voltage node P, the inverting input terminal is coupled to the reference voltage Vref, and the output terminal P_GT of the transconductance amplifier OTA is connected to the gate of the PMOS transistor used as the first switching element P0.

[0031] Figure 3 Shows Figure 2 FIG. 1 is a schematic diagram showing the variation of the power supply voltage Vdd, the reference voltage Vref and the voltage VP of the programming voltage node P in the electric fuse storage unit with time t. Figure 3As shown, the power supply voltage Vdd is a fixed value after the circuit is electrically stabilized, and the reference voltage Vref is a set value. When the first switch element P0 is turned on, the voltage VP of the programming voltage node P gradually increases with time. When VP exceeds the reference voltage Vref, negative feedback is performed through the above-mentioned negative feedback structure 100, so that VP falls back and gradually maintains near the reference voltage Vref. The difference between the voltage VP and the reference voltage Vref is equal to the gain error (Δ, Gain error) of the transconductance amplifier OTA.

[0032] In another embodiment, the negative feedback element adopts an error operational amplifier, whose non-inverting input terminal is coupled to the programming voltage node P, the inverting input terminal is coupled to the reference voltage Vref, and the output terminal is connected to the gate of the PMOS transistor used as the first switching element P0.

[0033] In the electric fuse storage unit described in the above embodiment, the fuse element F10 is coupled between the programming voltage node P and the ground. When the voltage VP of the programming voltage node P forms a programming voltage and a high-density current is formed between the programming voltage node P and the ground, the fuse element F10 can be blown within a preset time to achieve programming. The electric fuse storage unit has a negative feedback structure 100. The negative feedback structure 100 can adaptively adjust the voltage VP of the programming voltage node P to make it approach or equal to the reference voltage Vref, thereby ensuring that the programming voltage is within the expected range, thereby helping to form a stable programming current. For example, for the same electric fuse storage unit or more than two electric fuse storage units, by using the negative feedback structure 100, even if the first switch element P0 changes or has differences, when the reference voltage Vref setting value is the same, the voltage VP of the programming voltage node P approaches or is equal to the reference voltage Vref, so that the programming voltage applied to the fuse element F10 remains unchanged. It can be seen that by using the electric fuse storage unit described in the above embodiment, it is convenient to stably control the programming process and improve the blown yield.

[0034] An embodiment of the present invention further relates to a storage device, which includes the electric fuse storage unit described in the above embodiment.

[0035] The storage device, for example, includes a plurality of the electrical fuse storage units described in the above embodiments, and the structures of the electrical fuse storage units are the same, for example, their first switch elements P0 are the same, the second switch elements N0 are the same, and the fuse elements F10 are the same ("same" means that the design specifications such as material size are the same). In addition, the power supply voltage Vdd used by the electrical fuse storage units is the same, and the reference voltage Vref is the same, for example.

[0036] The electric fuse storage unit in the storage device has the above-mentioned negative feedback structure 100, which can adaptively adjust the voltage VP of the programming voltage node P to make it close to the reference voltage Vref, ensuring that the programming voltage is within the expected range, helping to stabilize the programming current, facilitating stable control of the programming process, improving the fuse yield, and helping to improve the performance of the storage device.

[0037] It should be noted that the embodiments in this specification are described in a progressive manner, and each part focuses on the differences from the previous part. The relevant parts can be understood by reference.

[0038] The above description is only a description of the preferred embodiment of the present invention, and is not any limitation on the scope of rights of the present invention. Any technical personnel in this field can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. An electric fuse storage unit, characterized in that: include: a fuse element having a first end and a second end, the first end being coupled to a programming voltage node, the second end being coupled to ground; A first switch element, coupled between a supply voltage and the programming voltage node; as well as A negative feedback structure is configured to reduce the opening degree of the first switch element to reduce the voltage of the programming voltage node when the voltage of the programming voltage node is greater than a reference voltage, and to increase the opening degree of the first switch element to increase the voltage of the programming voltage node when the voltage of the programming voltage node is less than the reference voltage.

2. The electric fuse storage unit according to claim 1, characterized in that: The negative feedback structure includes a negative feedback element, which is connected to the voltage of the programming voltage node and the reference voltage, and outputs a control signal for controlling the opening degree of the first switch element.

3. The electric fuse storage unit according to claim 2, characterized in that: The negative feedback element is a transconductance amplifier, a non-inverting input terminal of the transconductance amplifier is coupled to the programming voltage node, and an inverting input terminal of the transconductance amplifier is coupled to the reference voltage.

4. The electric fuse storage unit according to claim 2, characterized in that: The negative feedback element includes an error operational amplifier, a non-inverting input terminal of the error operational amplifier is coupled to the programming voltage node, and an inverting input terminal of the error operational amplifier is coupled to the reference voltage.

5. The electric fuse storage unit according to claim 1, characterized in that: The first switch element is a PMOS transistor, a source terminal of the PMOS transistor is coupled to the supply voltage, and a drain terminal of the PMOS transistor is coupled to the programming voltage node.

6. The electric fuse storage unit according to claim 1, characterized in that: The electrical fuse storage unit further includes a second switch element coupled between the second end of the fuse element and ground.

7. The electric fuse storage unit according to claim 6, characterized in that: The second switch element is an NMOS transistor. A source terminal of the NMOS transistor is grounded, and a drain terminal of the NMOS transistor is coupled to the second terminal of the fuse element.

8. A storage device, characterized in that: Comprising the electric fuse storage unit as claimed in any one of claims 1 to 7.

9. The storage device according to claim 8, wherein: The storage device includes a plurality of the electric fuse storage units, and the first switch elements and the fuse elements in each of the electric fuse storage units are the same.

10. The storage device according to claim 9, wherein: The electrical fuse storage units use the same supply voltage and the same reference voltage.

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