CN112929015B

CN112929015B - switching circuit

Info

Publication number: CN112929015B
Application number: CN202110088729.9A
Authority: CN
Inventors: 李弦泰
Original assignee: Dongxin Semiconductor Co ltd
Current assignee: Dongxin Semiconductor Co ltd
Priority date: 2021-01-22
Filing date: 2021-01-22
Publication date: 2023-10-31
Anticipated expiration: 2041-01-22
Also published as: CN112929015A

Abstract

The application provides a switching circuit, which can replace a commonly used high-voltage switching circuit when the input voltage is medium-low voltage, and can reduce the layout size of components on the basis of realizing a switching function. The switching circuit includes: the control module is composed of a plurality of low-voltage MOSFETs, and the source electrode of the control module receives the power supply voltage of the circuit and outputs the power supply voltage as a control voltage; and a switching module that is configured by a plurality of MOSFETs, receives the control voltage output from the control module, and switches according to the control voltage, wherein the plurality of MOSFETs configuring the switching module include only 1 high-voltage MOSFET.

Description

Switching circuit

Technical Field

The present application relates to a switching circuit, and more particularly, to a switching circuit for use in a computer flash memory device.

Background

A computer flash memory device (hereinafter sometimes referred to as "NAND flash memory") is a storage device that performs better than a hard disk drive in some performance, and is particularly apparent in low-capacity applications of no more than 4 GB. NAND flash has proven to be very attractive as products with lower power consumption, lighter weight and better performance continue to be pursued.

NAND flash memory is a non-volatile memory technology that can be used to store voice, image, and other data for a variety of electronic products including, but not limited to, computers, cellular telephones, personal digital assistants, digital cameras, video cameras, audio recorders, MP3 players, hand-held personal computers, gaming machines, facsimile machines, scanners, printers, and the like.

In general NAND flash, various types of BIAS voltages (hereinafter, sometimes referred to as "BIAS voltages") are required in order to operate normally, and these BIAS voltages range from about 0V to about 30V. Among them, the magnitude of the bias voltage is different according to various operations (PGM, read, erase) and the like, and various types of bias voltages are connected to each WL, DSL, SSL and virtual WL and the like.

These bias voltages described above are generally classified into two types.

One of them is a voltage equal to or lower than VDD (operating voltage inside the device), and VDD is directly received as a power supply voltage of each circuit.

The other is a voltage above VDD, typically generated using a charge pump or high voltage regulator.

These generated voltages are transmitted to each WL, DSL, SSL and virtual WL and the like through a switch (i.e., a switching circuit).

Fig. 1 is a block diagram showing a high voltage generator and a high voltage switching circuit (High Voltage Switch, hereinafter sometimes simply referred to as "HVSW"). As is clear from fig. 1, in the prior art, various types of voltages (voltages of VDD or lower, and voltages of 0V-5V, 5V-15V, and 10V-30V) are output through a high voltage switching circuit (HVSW), respectively.

Further, for example, patent document 1 (CN 108288485 a) discloses a high-voltage switching circuit of a nonvolatile memory device, which includes a high-voltage transistor, logic, and a high-voltage switch.

In addition, patent document 2 (CN 2682540Y) discloses a bootstrap high-voltage switching circuit for use in a memory cell, which includes three MOSFETs (M1, M2, M3) and one bootstrap capacitor C.

Prior art literature

Patent literature

Patent document 1: CN108288485A

Patent document 2: CN2682540Y

Disclosure of Invention

Technical problem to be solved by the application

Currently, two types of high voltage switching circuits are commonly used in existing NAND flash memories.

As shown in fig. 2, one type of high voltage switching circuit (HVSW) 100 is composed of a deep N-hydrazine low voltage NMOSFET, an intrinsic high voltage NMOSFET, a high voltage NMOSFET, and a MOS capacitor. Wherein the control module 101 receives VPP from the charge pump as a source and transmits VPP voltage to the gate of the switching module 102. Here, the VPP voltage is applied to the high-voltage NMOSFET as a gate voltage SEL (i.e., control voltage), thereby controlling the on/off of the switching element, thereby realizing the switching function of the switching circuit 100.

In addition, as shown in fig. 3, another type of high voltage switching circuit (HVSW) 200 is composed of a depletion type low voltage NMOSFET, a high voltage PMOSFET, and a high voltage NMOSFET, and the control module 201 transmits VPP voltage to the gate of the switching module 202 in the same manner. Here, similarly, the VPP voltage is applied to the high-voltage NMOSFET as a gate voltage SEL (i.e., control voltage), thereby controlling the on/off of the switching element, and realizing the switching function of the switching circuit 200.

The high-voltage switches of patent document 1 and patent document 2 also include a plurality of high-voltage MOSFETs, and the functions of the switching circuit are also realized by a similar configuration.

However, the existing high-voltage switching circuit is provided with a plurality of high-voltage MOSFETs and requires separation of hydrazine according to devices, and hydrazine space of some devices is large, so that a considerable area is required for layout.

As shown in fig. 1-3, when a voltage higher than VDD is transmitted to WL (word line), the gate voltage of the switch should be higher than VDD, at which time the high voltage switching circuit may transmit VPP voltage to the gate.

In addition, the respective high voltage switching circuits corresponding to the voltage ranges of different sizes are generally connected together, and thus, even in the case of off (off), the output of each switch is connected to other high voltage biases, and thus, it is necessary to use a high voltage component (e.g., a high voltage MOSFET) to avoid the problem of breakdown by the MOSFET due to an external high voltage higher than BV (breakdown voltage: breakdown voltage) of the MOSFET itself.

The present application has been made in view of the above-described circumstances, and an object thereof is to provide a switching circuit capable of reducing the layout size of components in addition to realizing a switching function by replacing a high-voltage switching circuit that is generally used when an input voltage is a medium-low voltage.

Technical proposal adopted for solving the technical problems

A switch circuit according to an embodiment of the present application includes: the control module is composed of a plurality of low-voltage MOSFETs, and the source electrode of the control module receives the power supply voltage of the circuit and outputs the power supply voltage as a control voltage; and a switching module that is configured by a plurality of MOSFETs, receives a control voltage output from the control module, and switches according to the control voltage, wherein the plurality of MOSFETs configuring the switching module include only 1 high-voltage MOSFET.

In the first aspect of the switch circuit according to the second aspect of the present application, the switch module is preferably configured by connecting 1 low-voltage NMOSFET and 1 high-voltage NMOSFET in series.

In the second aspect of the switching circuit according to the third aspect of the present application, it is preferable that the 1 high voltage NMOSFET is an intrinsic high voltage NMOSFET.

In the second aspect of the switching circuit according to the fourth aspect of the present application, the 1 high voltage NMOSFET is preferably a depletion type high voltage NMOSFET.

In the switch circuit according to the fifth aspect of the present application, in the first aspect, the control module is preferably a level shifter circuit including 3 low-voltage PMOSFETs and 3 low-voltage NMOSFETs.

In the switch circuit according to the sixth aspect of the present application, in the fifth aspect, it is preferable that a power supply voltage of the circuit received by the source of the control module is 5V or less.

In the switch circuit according to the seventh aspect of the present application, in the first aspect, the input voltage of the switch circuit is preferably 4V or less.

In the switch circuit according to the eighth aspect of the present application, in the second aspect, it is preferable that the control voltage outputted from the control module is applied to the gates of the low voltage NMOSFET and the high voltage NMOSFET.

In the switch circuit according to the ninth aspect of the present application, in the first aspect, the power supply voltage of the circuit is preferably supplied by a high-voltage regulator or a charge pump.

Effects of the application

According to the switching circuit, the layout size of components can be reduced on the basis of realizing the switching function.

Drawings

Fig. 1 is a block diagram showing a conventional high voltage generator and high voltage switch (High Voltage Switch, HVSW).

Fig. 2 is a diagram showing a detailed structure of one example of a conventional high-voltage switching circuit.

Fig. 3 is a diagram showing a detailed structure of another example of a conventional high-voltage switching circuit.

Fig. 4 is a block diagram showing a configuration of a switching circuit according to embodiment 1 of the present application.

Fig. 5 is a block diagram showing the configuration of a switching circuit according to embodiment 2 of the present application.

Fig. 6 is a diagram showing a detailed structure of the level shift circuit.

Detailed Description

Hereinafter, a specific embodiment of the present application will be described with reference to the drawings.

Embodiment 1.

Fig. 4 is a block diagram showing the configuration of a switching circuit 300 according to embodiment 1 of the present application.

As shown in fig. 4, the switching circuit 300 includes a control module 301 and a switching module 302.

The control module 301 is a level shift circuit 303, the specific structure of which is shown in fig. 6.

As shown in fig. 6, the level shift circuit 303 is constituted by 3 low-voltage PMOSFETs (hereinafter, abbreviated as "LVPs" in some cases) and 3 low-voltage NMOSFETs (hereinafter, abbreviated as "LVNs" in some cases), in which a pair of MOSFETs constitute an inverter. The source voltage (hereinafter, sometimes simply referred to as "VMV") of the level shift circuit 303 uses a voltage of about 5V or less, which is lower than the Breakdown Voltage (BV) of the low voltage components (LVP and LVN), and thus, a problem of breakdown does not occur. In addition, the VMV is provided by a high voltage regulator or a charge pump, and may also be used in other circuits.

The switching module 302 includes a Low Voltage NMOSFET (LVN) 304 and an intrinsic high voltage NMOSFET (hereinafter sometimes simply referred to as "native_hvn"), which are connected in series. When the switching circuit 300 operates, en_mv output from the control module 301 is applied to gates of the LVN304 and the native_hvn305 as a gate voltage SEL (i.e., control voltage).

Since the output terminal (hereinafter, sometimes simply referred to as "OUT") of the switching circuit 300 is connected to other high-voltage switching circuits, in order to avoid the problem of breakdown, one high-voltage switching element (i.e., native_hvn 305) is used before the output terminal (OUT), and all switching elements in the switching circuit 300 are low-voltage switching elements (i.e., low-voltage MOSFETs).

In this case, since only one high-voltage MOSFET is provided, the layout size of the components of the switching circuit is reduced by 5 to 6 times as compared with the conventional high-voltage switching circuit.

Next, a switching operation of the switching circuit 300 will be described.

A. Enabling

When enabled, the EN signal (i.e., enable signal) is input to the level shifter circuit 303. At the same time, VMV of about 5V or less is input to the level shifter circuit 303, en_mv identical to VMV voltage is output from the level shifter circuit 303, and is input to the LVN304 and native_hvn305 of the switching module 302 as the gate voltage SEL.

For LVN304, which is a common low voltage NMOSFET, the turn-on voltage (threshold voltage) Vth is about 0.7V. Since a 5V SEL input is to its gate, LVN304 is on.

At node a, LVN304 may pass a voltage of about 4V (SEL-vth=about 4V).

The native_hvn305 has an on voltage (threshold voltage) of almost 0V, and is therefore fully on, and can pass all input voltages of VMV (about 5V) or less. That is, in this case, the switching circuit 300 is in the on state. Although the LVN304 is a low-voltage NMOSFET, since only about 4V passes, BV does not exceed the LVN304, and breakdown does not occur.

Therefore, the switching circuit 300 according to the present application can be used to replace a conventional high voltage switching circuit (HVSW) when the input voltage is about 4V or less, which is an input voltage that is converted to about 4V. In this case, the switching function can be realized similarly to the HVSW, but since the switching circuit 300 according to the present application includes only one high-voltage NMOSFET (i.e., native_hvn 305), the layout area of the components can be reduced by about 5 to 6 times as compared to the HVSW.

B. Disabling

When disabled, there is no input of the EN signal, so en_mv becomes 0V.

In this case, the gate voltage SEL also becomes 0V, that is, the control voltage input to the gates of the LVN304 and native_hvn305 also becomes 0V.

At this time, since the turn-on voltage of native_hvn305 is 0V or less, it is not completely turned off. However, since the Vth of the LVN304 is about 0.7V, the LVN304 is completely turned off. In this case, any leakage current can be blocked by the LVN304, and at the same time, a high voltage can be blocked by the native_hvn 305. Therefore, neither leakage current nor breakdown occurs. That is, the switching circuit 300 is in an off state at this time.

As described above, according to the switching circuit 300 of embodiment 1, when the input voltage is a low-medium voltage (4V or less), the switching circuit 300 can be used to perform the switching operation normally instead of the high-voltage switching circuit that is generally used, and neither leakage current nor breakdown occurs. And since the switching circuit according to the present application includes only 1 high voltage NMOSFET (i.e., native_hvn 305), the layout size of the components is reduced, and the layout area can be reduced by about 5 to 6 times as compared with the commonly used high voltage switching circuit.

Embodiment 2.

Fig. 5 is a block diagram showing a configuration of a switching circuit 400 according to embodiment 2 of the present application.

As shown in fig. 5, the switching circuit 400 includes a control module 401 and a switching module 402.

The control block 401 is a level shift circuit 403, and the specific configuration is shown in fig. 6, similarly to the level shift circuit 303 according to embodiment 1.

As shown in fig. 6, the level shift circuit 403 is constituted by 3 low-voltage PMOSFETs (LVPs) and 3 low-voltage NMOSFETs (LVNs), in which a pair of MOSFETs constitute an inverter. The source voltage (VMV) of the level shift circuit 403 uses a voltage of about 5V or less, which is lower than the Breakdown Voltage (BV) of the low voltage components (LVP and LVN), and thus no breakdown occurs. In addition, the VMV is provided by a high voltage regulator or a charge pump, and may also be used in other circuits.

The switching module 402 includes a Low Voltage NMOSFET (LVN) 404 and a Depletion mode high voltage NMOSFET (hereinafter sometimes simply referred to as "depletion_hvn") 405, which are connected in series. When the switching circuit 400 operates, en_mv output from the control module 401 is applied to gates of the LVN 404 and the display_hvn 405 as a gate voltage SEL (i.e., control voltage).

Since the output terminal (OUT) of the switching circuit 400 is connected to other high-voltage switching circuits, in order to avoid breakdown, one high-voltage switching element (i.e., the breakdown_hvn 405) is used before the output terminal (OUT), and all switching elements in the switching circuit 400 are low-voltage switching elements (i.e., low-voltage MOSFETs).

Next, a switching operation of the switching circuit 400 will be described.

A. Enabling

When enabled, the EN signal is input to the level shift circuit 403. At the same time, VMV of about 5V or less is input to the level shifter circuit 403, en_mv identical to VMV voltage is output from the level shifter circuit 403, and is input as a gate voltage SEL (i.e., control voltage) to the LVN 404 and the display_hvn 405 of the switching module 402.

For the LVN 404, which is a normal low voltage NMOSFET, the turn-on voltage (threshold voltage) Vth is about 0.7V. Since a 5V SEL input is to its gate, LVN 404 is on.

At node a, LVN 404 may pass a voltage of about 4V (SEL-vth=about 4V).

For the display_HVN 405, the turn-on voltage (threshold voltage) is about-4V, and thus is fully conductive, allowing all input voltages below VMV (about 5V) to pass. That is, in this case, the switch circuit 400 is in the on state. Although the LVN 404 is a low-voltage NMOSFET, since only about 4V passes, BV does not exceed the LVN 404, and breakdown does not occur.

Therefore, the switching circuit 400 can be used to convert an input voltage to about 4V, that is, when the input voltage is 4V or less, the switching circuit 400 according to the present application can be used in place of the conventional high voltage switching circuit (HVSW). In this case, the switching function can be realized similarly to the HVSW, but since the switching circuit 400 according to the present application includes only one high-voltage NMOSFET (i.e., the design_hvn 405), the layout area of the components can be reduced by about 5 to 6 times as compared to the HVSW.

B. Disabling

When disabled, there is no input of the EN signal, so en_mv becomes 0V.

In this case, the gate voltage SEL also becomes 0V, that is, the control voltage input to the gates of the LVN 404 and the display_hvn 405 also becomes 0V.

At this time, since the turn-on voltage of native_hvn 405 is about-4V, the voltage at node a is about 4V when the design_hvn 405 is turned on. In addition, since Vth of the LVN 404 is about 0.7V, the LVN 404 is completely turned off. In this case, since the voltage across the LVN 404 is 4V and the BV of the LVN 404 is not exceeded, the LVN 404 does not break down, and any leakage current can be blocked by the LVN 404. Meanwhile, the high voltage may also be blocked by the breakdown_hvn 405, so that neither leakage current nor breakdown occurs. That is, the switching circuit 400 is in an off state at this time.

As described above, according to the switching circuit 400 of embodiment 2, when the input voltage is a low-medium voltage (4V or less), the switching circuit 400 can be used to perform the switching operation normally instead of the high-voltage switching circuit that is generally used, and neither leakage current nor breakdown occurs. And since the switching circuit 400 according to the present application includes only 1 high voltage NMOSFET (i.e., the description_hvn 405), the layout size of the components is reduced, and the layout area can be reduced by about 5 to 6 times compared to the commonly used high voltage switching circuit.

While various exemplary embodiments have been described, the various features, aspects, and functions described in the embodiments are not limited to application to the specific embodiments, and can be applied to the embodiments alone or in various combinations.

Accordingly, numerous modifications, not illustrated, are contemplated as falling within the scope of the disclosed technology. For example, the case where at least 1 component is deformed, the case where addition is performed, or the case where omission is performed is also included.

Industrial applicability

The switch circuit can be used as a medium-low voltage switch circuit for various computer flash memory devices.

Description of the reference numerals

100. 200 high-voltage switch circuit

300. 400 switch circuit

101. 201, 301, 401 control module

102. 202, 302, 402 switch module

303. 403 level conversion circuit

304. 404 low voltage NMOSFET

305. Intrinsic high voltage NMOSFET

405. Depletion mode high voltage NMOSFET.

Claims

1. A switching circuit, comprising:

the control module is composed of a plurality of low-voltage MOSFETs, and the source electrode of the control module receives the power supply voltage of the circuit and outputs the power supply voltage as a control voltage; and

a switching module composed of a plurality of MOSFETs, receiving a control voltage outputted from the control module, and switching according to the control voltage,

of the plurality of MOSFETs constituting the switching module, only 1 high-voltage MOSFET is included.

2. The switching circuit according to claim 1, wherein,

the switch module is formed by connecting 1 low-voltage NMOSFET and 1 high-voltage NMOSFET in series.

3. The switching circuit according to claim 2, wherein,

the 1 high voltage NMOSFET is an intrinsic high voltage NMOSFET.

4. The switching circuit according to claim 2, wherein,

the 1 high-voltage NMOSFET is a depletion type high-voltage NMOSFET.

5. The switching circuit according to claim 1, wherein,

the control module is a level shift circuit, which is composed of 3 low-voltage PMOSFETs and 3 low-voltage NMOSFETs.

6. The switching circuit according to claim 5, wherein,

the source of the control module receives a supply voltage of the circuit below 5V.

7. The switching circuit according to claim 1, wherein,

the input voltage of the switching circuit is below 4V.

8. The switching circuit according to claim 2, wherein,

the control voltage output by the control module is applied to the gates of the low voltage NMOSFET and the high voltage NMOSFET.

9. The switching circuit according to claim 1, wherein,

the supply voltage of the circuit is provided by a high voltage regulator or a charge pump.