阅读说明：本技术 电压控制装置及存储器系统 (Voltage control device and memory system ) 是由 古惟铭 王炜强 于 2018-12-26 设计创作，主要内容包括：本发明公开了一种电压控制装置,电压控制装置包括第一电荷泵、第二电荷泵、第一电源开关、第二电源开关及第三电源开关。第一电荷泵接收第一系统电压,并根据第一系统电压产生第一应用电压。第一电源开关接收第一系统电压及第一应用电压。第二电荷泵耦接于第一电源开关的输出端,并根据第二电荷泵的输入端所接收的电压产生第二应用电压。第二电源开关接收第二应用电压。第三电源开关的第一输入端耦接于第一电荷泵的输出端,而第三电源开关的第二输入端耦接于第二电荷泵的输出端。(The invention discloses a voltage control device which comprises a first charge pump, a second charge pump, a first power switch, a second power switch and a third power switch. The first charge pump receives a first system voltage and generates a first application voltage according to the first system voltage. The first power switch receives a first system voltage and a first application voltage. The second charge pump is coupled to the output end of the first power switch and generates a second application voltage according to the voltage received by the input end of the second charge pump. The second power switch receives a second application voltage. The first input terminal of the third power switch is coupled to the output terminal of the first charge pump, and the second input terminal of the third power switch is coupled to the output terminal of the second charge pump.)

1. A voltage control apparatus, comprising:

A first charge pump having an input terminal for receiving a first system voltage and an output terminal for outputting a first application voltage, the first charge pump being configured to generate the first application voltage according to the first system voltage;

A first power switch having a first input terminal for receiving the first system voltage, a second input terminal for receiving the first application voltage, and an output terminal;

a second charge pump having an input coupled to the output of the first power switch and an output for outputting a second applied voltage, the second charge pump being configured to generate the second applied voltage according to a voltage received at the input of the second charge pump;

a second power switch having an input terminal for receiving the second application voltage and an output terminal; and

a third power switch having a first input coupled to the output of the first charge pump, a second input coupled to the output of the second charge pump, and an output.

2. The voltage control apparatus of claim 1, wherein when the voltage control apparatus is in the first mode:

The output terminal of the first power switch outputs the first application voltage;

The output terminal of the second power switch outputs the second application voltage; and

The second applied voltage is higher than the first applied voltage, and the first applied voltage is higher than the first system voltage.

3. The voltage control apparatus of claim 2 wherein the first mode is configured to provide a clear voltage required for a memory cell to perform a clear operation.

4. The voltage control apparatus of claim 1, wherein when the voltage control apparatus is in the second mode:

The output terminal of the first power switch outputs the first system voltage;

the third power switch turns on a current path between the first input terminal of the third power switch to the output terminal of the third power switch to output the first application voltage, and simultaneously turns on a current path between the second input terminal of the third power switch to the output terminal of the third power switch to output the second application voltage; and

The first application voltage is equal to the second application voltage, and the first application voltage is higher than the first system voltage.

5. the voltage control apparatus of claim 4, wherein the second mode is used to provide a write voltage required by the memory cell to perform a write operation.

6. The voltage control device of claim 4, further comprising a fourth power switch having a first input for receiving the first system voltage, a second input coupled to the output of the first charge pump, and an output.

7. The voltage control apparatus of claim 6, wherein when the voltage control apparatus is in the third mode:

The output terminal of the fourth power switch outputs the first application voltage;

The first application voltage is greater than a minimum variation value of the first system voltage and less than a maximum variation value of the first system voltage.

8. the voltage control apparatus of claim 7 wherein the third mode is configured to provide an operating voltage for the memory cell to perform a read operation.

9. The voltage control apparatus of claim 1 wherein the current load supported by the first charge pump is greater than the current load supported by the second charge pump.

10. A memory system, comprising:

A voltage control device comprising:

A first charge pump having an input terminal for receiving a first system voltage and an output terminal for outputting a first application voltage, the first charge pump being configured to generate the first application voltage according to the first system voltage;

A first power switch having a first input terminal for receiving the first system voltage, a second input terminal for receiving the first application voltage, and an output terminal;

A second charge pump having an input coupled to the output of the first power switch and an output for outputting a second applied voltage, the second charge pump being configured to generate the second applied voltage according to a voltage received at the input of the second charge pump;

a second power switch having an input terminal for receiving the second application voltage and an output terminal; and

A third power switch having a first input coupled to the output of the first charge pump, a second input coupled to the output of the second charge pump, and an output; and

And the memory array comprises a plurality of memory cells and is coupled to the voltage control device, and the memory array receives and operates the memory cells according to the voltage output by the voltage control device.

11. The memory system of claim 10, wherein when the memory system is performing a clear operation:

the output terminal of the first power switch outputs the first application voltage;

The output terminal of the second power switch outputs the second application voltage;

The memory array receiving the second applied voltage to perform a clear operation on at least one of the plurality of memory cells; and

The second applied voltage is higher than the first applied voltage, and the first applied voltage is higher than the first system voltage.

12. The memory system of claim 10, wherein when the memory system is performing a write operation:

The output terminal of the first power switch outputs the first system voltage;

The third power switch turns on a current path between the first input terminal of the third power switch to the output terminal of the third power switch to output the first application voltage, and simultaneously turns on a current path between the second input terminal of the third power switch to the output terminal of the third power switch to output the second application voltage;

The first application voltage is equal to the second application voltage, and the first application voltage is higher than the first system voltage; and

the memory array receives the first applied voltage and the second applied voltage to perform a write operation on at least one memory cell of the plurality of memory cells.

13. the memory system of claim 12, further comprising a level shift driver, coupled to the voltage control device and the memory array, for shifting a level of an input logic voltage to generate a driving control voltage for controlling the memory array;

the voltage control apparatus further includes a fourth power switch having a first input for receiving the first system voltage, a second input coupled to the output of the first charge pump, and an output coupled to the level shift driver.

14. The memory system of claim 13, wherein when the memory system is performing a read operation:

The output terminal of the fourth power switch outputs the first application voltage;

The first application voltage is greater than the minimum variation value of the first system voltage and less than the maximum variation value of the first system voltage; and

The potential offset driver receives the first application voltage to offset a potential of the input logic voltage to generate the driving control voltage.

15. The memory system of claim 10, wherein the current load supported by the first charge pump is greater than the current load supported by the second charge pump.

Technical Field

The present invention relates to a voltage control device, and more particularly, to a voltage control device with a small volume characteristic for use in a memory system.

Background

in order to meet the demand for low power consumption of electronic devices, the power specifications of Integrated Circuits (ICs) are often redesigned to be able to operate in a low voltage environment to reduce power consumption. For example, integrated circuits that were powered by 5V in the past are now often reduced to 3.3V or even below 2V. Although low voltage operation can reduce power consumption, even circuits with low power specifications may require higher voltages to complete operation in some applications. For example, flash memory requires higher voltages for write and erase operations. Wherein the higher voltage is often provided by a charge pump circuit.

Since the flash memory may require two different sets of high voltages during the write and erase operations, and the current loads required by the two may be different, in the prior art, two different sets of charge pump circuits are used to generate the voltages required for the write and erase operations, respectively. In this case, the charge pump for generating higher voltage requires a plurality of stages of boost circuits, and the charge pump for providing higher load current uses the boost circuit components with larger size, both of which require an increased circuit area and do not meet the current circuit design requirements.

Disclosure of Invention

An embodiment of the present invention provides a voltage control apparatus including a first charge pump, a second charge pump, a first power switch, a second power switch, and a third power switch.

The first charge pump has an input terminal and an output terminal, the input terminal of the first charge pump receives a first system voltage, and the output terminal of the first charge pump outputs a first application voltage. The first charge pump generates a first application voltage according to a first system voltage.

The first power switch (power switch) has a first input terminal, a second input terminal and an output terminal. The first input terminal of the first power switch receives a first system voltage, and the second input terminal of the first power switch receives a first application voltage.

the second charge pump has an input terminal and an output terminal, the input terminal of the second charge pump is coupled to the output terminal of the first power switch, and the output terminal of the second charge pump outputs a second application voltage. The second charge pump generates a second applied voltage according to the voltage received by the input terminal of the second charge pump.

the second power switch has an input terminal and an output terminal, and the input terminal of the second power switch receives a second application voltage. The third power switch has an input terminal and an output terminal, the first input terminal of the third power switch is coupled to the output terminal of the first charge pump, and the second input terminal of the third power switch is coupled to the output terminal of the second charge pump.

Another embodiment of the invention provides a memory system comprising a voltage control device and a memory array.

The voltage control device comprises a first charge pump, a second charge pump, a first power switch, a second power switch and a third power switch.

The first charge pump has an input terminal and an output terminal, the input terminal of the first charge pump receives a first system voltage, and the output terminal of the first charge pump outputs a first application voltage. The first charge pump generates a first application voltage according to a first system voltage.

the first power switch has a first input terminal, a second input terminal and an output terminal. The first input terminal of the first power switch receives a first system voltage, and the second input terminal of the first power switch receives a first application voltage.

The second charge pump has an input terminal and an output terminal, the input terminal of the second charge pump is coupled to the output terminal of the first power switch, and the output terminal of the second charge pump outputs a second application voltage. The second charge pump generates a second applied voltage according to the voltage received by the input terminal of the second charge pump.

the second power switch has an input terminal and an output terminal, and the input terminal of the second power switch receives a second application voltage. The third power switch has an input terminal and an output terminal, the first input terminal of the third power switch is coupled to the output terminal of the first charge pump, and the second input terminal of the third power switch is coupled to the output terminal of the second charge pump.

The memory array is coupled to the voltage control device and comprises a plurality of memory units. The memory array receives and operates the memory unit according to the voltage output by the voltage control device.

drawings

fig. 1 is a schematic diagram of a voltage control apparatus according to an embodiment of the invention.

FIG. 2 is a diagram of a memory system according to an embodiment of the invention.

Wherein the reference numerals are as follows:

100. 200 voltage control device

110. 210 first charge pump

120. 220 second charge pump

130. 230 first power switch

140. 240 second power switch

150. 250 third power switch

260 fourth power switch

v1 first system voltage

VP1 first application Voltage

VP2 second applied voltage

20 memory system

Vctrl1 input logic voltage

Vctrl2 drive control voltage

22 memory array

22A memory cell

24 potential offset driver

Detailed Description

Fig. 1 is a schematic diagram of a voltage control apparatus 100 according to an embodiment of the invention. The voltage control apparatus 100 includes a first charge pump 110, a second charge pump 120, a first power switch (power switch)130, a second power switch 140, and a third power switch 150.

The first charge pump 110 has an input terminal and an output terminal, the input terminal of the first charge pump 110 can receive the first system voltage V1, and the first charge pump 110 can generate the first application voltage VP1 according to the first system voltage V1 and output the first application voltage VP1 from the output terminal of the first charge pump 110. In some embodiments of the present invention, the first system voltage V1 may be an operation voltage required by a circuit in the system by default and may be provided by a fixed voltage source, and the first application voltage VP1 is an operation voltage required by some specific applications or circuits.

The first power switch 130 has a first input terminal, a second input terminal and an output terminal, the first input terminal of the first power switch 130 can receive the first system voltage V1, and the second input terminal of the first power switch 130 can receive the first application voltage VP 1. The first power switch 130 is switchable between a first input terminal and a second input terminal to output the first system voltage V1 or the first application voltage VP1 from an output terminal thereof.

the second charge pump 120 has an input terminal and an output terminal, the input terminal of the second charge pump 120 is coupled to the output terminal of the first power switch 130, and the second charge pump 120 generates the second application voltage VP2 according to the voltage received by the input terminal of the second charge pump 120 and outputs the second application voltage VP2 from the output terminal of the second charge pump 120.

The second power switch 140 has an input terminal and an output terminal, the input terminal of the second power switch 140 can receive the second application voltage VP2, and the second power switch 140 can output the second application voltage VP2 or stop outputting the voltage according to the operation mode of the voltage control apparatus 100.

The third power switch 150 has a first input terminal, a second output terminal and an output terminal. A first input terminal of the third power switch 150 is coupled to the output terminal of the first charge pump 110, and a second input terminal of the third power switch 150 is coupled to the output terminal of the second charge pump 120. The third power switch 150 can be switched between the first input terminal and the second input terminal to output the voltage outputted by the first charge pump 110 and/or the second charge pump 120 from the output terminal thereof.

through the first power switch 130, the second power switch 140 and the third power switch 150, the voltage control apparatus 100 can more flexibly utilize the first charge pump 110 and the second charge pump 120 to output the required voltage to meet the application requirements.

for example, when the voltage control apparatus 100 operates in the first mode to output the second higher application voltage VP2, the output terminal of the first power switch 130 can output the first application voltage VP1 generated by the first charge pump 110, the second charge pump 120 receives the first application voltage VP1 and can generate the second application voltage VP2 according to the first application voltage VP1, and the output terminal of the second power switch 140 can output the second application voltage VP2 for subsequent applications. In some embodiments, the first application voltage VP1 may be higher than the first system voltage V1, and the second application voltage VP2 may be higher than the first application voltage VP1, for example, the first system voltage V1 may be, for example, 2.5V, the first application voltage VP1 may be, for example, 8V, and the second application voltage VP2 may be, for example, 15V.

That is, the first charge pump 110 can boost the first system voltage V1 to generate the first application voltage VP1, and the second charge pump 120 can then boost the first application voltage VP1 to generate the second application voltage VP 2. In this way, the second charge pump 120 does not need to directly boost the first system voltage V1 to generate the second application voltage VP2, so that the number of boosting stages required inside the second charge pump 120 can be reduced, and the required circuit area can also be reduced.

In addition, when the voltage control apparatus 100 operates in the second mode to output the application voltage with a larger required load current, the output terminal of the first power switch 130 may output the first system voltage V1. In this case, the first charge pump 110 and the second charge pump 120 are boosted according to the first system voltage V1 and generate the first application voltage VP1 and the second application voltage VP2, respectively. In this embodiment, the first application voltage VP1 may be substantially equal to the second application voltage VP2, and the first application voltage VP1 may be higher than the first system voltage V1. For example, the first system voltage V1 may be, for example, 2.5V, and the first application voltage VP1 and the second application voltage VP2 may be, for example, 8V. In some embodiments of the present invention, the first charge pump 110 and the second charge pump 120 may include a voltage comparator, and the voltage comparator may compare the output voltages of the first charge pump 110 and the second charge pump 120 with a default reference voltage, and only when the output voltages of the first charge pump 110 and the second charge pump 120 are lower than the reference voltage, an internal boosting mechanism is activated for boosting. Thus, by adjusting the voltage value of the reference voltage, the first application voltage VP1 and the second application voltage VP2 can be adjusted to the required voltage values.

In this case, the third power switch 150 may conduct a current path from the first input terminal of the third power switch 150 to the output terminal of the third power switch 150 to output the first application voltage VP1, and simultaneously conduct a current path from the second input terminal of the third power switch 150 to the output terminal of the third power switch 150 to output the second application voltage VP 2. In this way, the first charge pump 110 and the second charge pump 120 can provide the application voltage required by the subsequent application together, so that the current load required by a single charge pump can be reduced, and the first charge pump 110 and the second charge pump 120 can be implemented by selecting circuit components with smaller sizes to reduce the circuit area.

In addition, in some embodiments of the present invention, the current loads supported by the first charge pump 110 and the second charge pump 120 may also be different, for example, the current load supported by the first charge pump 110 may be larger than the current load supported by the second charge pump 120. In this way, in the first mode, the second charge pump 120 can more stably utilize the first application voltage VP1 for boosting, and in the second mode, the first charge pump 110 can provide most of the current load, so that the first charge pump 110 and the second charge pump 120 can cooperate with each other in different modes, and the circuit design is more flexible.

Since the voltage control apparatus 100 can flexibly generate the required first application voltage VP1 and the second application voltage VP2 by using the first charge pump 110 and the second charge pump 120 in different modes, the circuit utilization efficiency of the voltage control apparatus 100 can be improved, and the overall required circuit area can be reduced.

in some embodiments of the present invention, the voltage control apparatus 100 can be applied in a memory system and is used to provide voltages required for a write operation and a clear operation of a memory cell. Taking the example of a memory cell using Fowler-Nordheim tunneling (F-N tunneling) for erasing and using Hot carrier Injection (CHE Injection) for writing, the memory cell requires a high voltage with a large current, such as 8V, during the writing operation, and the voltage control apparatus 100 can operate in the second mode. In the erase operation, the memory cell needs a higher voltage, such as 15V, than in the write operation, and the voltage control device can operate in the first mode.

FIG. 2 is a diagram of a memory system 20 according to an embodiment of the invention. The memory system 20 includes a voltage control device 200 and a memory array 22. Voltage control device 200 has a similar structure and may operate according to similar principles as voltage control device 100. The memory array 22 is coupled to the voltage control device 200 and may include a plurality of memory cells 22A.

When the memory system 20 is performing a clear operation, the voltage control device 200 may enter the first mode. At this time, the output terminal of the first power switch 230 can output the first application voltage VP1 generated by the first charge pump 210, so that the second charge pump 220 can boost the voltage according to the first application voltage VP1 to generate the second application voltage VP2, and the output terminal of the second power switch 240 can output the second application voltage VP 2. In some embodiments of the present invention, the second application voltage VP2 may be higher than the first application voltage VP1, and the first application voltage VP1 may be higher than the first system voltage V1. As a result, the memory array 22 receives the second applied voltage VP2 as an erase voltage and performs an erase operation on at least one of the memory cells 22A.

When the memory system 20 is performing a write operation, the voltage control device 200 may enter the second mode. The output terminal of the first power switch 240 can output the first system voltage V1, and the first charge pump 210 and the second charge pump 220 can generate the substantially equal first application voltage VP1 and second application voltage VP2 according to the first system voltage V1. In addition, the third power switch 250 can output the first application voltage VP1 and the second application voltage VP2 simultaneously to respond to the larger current load required by the write operation. In this case, the memory array 22 can receive the first application voltage VP1 and the second application voltage VP2 as the write voltage and perform a write operation on at least one memory cell therein.

furthermore, in some embodiments of the present invention, when a general selection or read operation is performed on the memory cells in the memory array 22, the external input logic voltage Vctrl1 may be a lower operation voltage in the system, for example, between 1.2V and 2V. In this case, in order to be able to smoothly drive the transistors or other circuit components in the memory unit 22A, the memory system 20 may also include a level shift driver 24. The level shift driver 24 is coupled to the voltage control device 200 and the memory array 22, and can shift the level of the input logic voltage Vctrl1 to generate a driving control voltage Vctrl2 for controlling the memory array 22.

in general, the level shift driver 24 may output the corresponding driving control voltage Vctrl2 according to the level of the input logic voltage Vctrl1, so that the high level of the driving control voltage Vctrl2 can be similar to the first system voltage V1, for example, to drive the memory cells in the memory array 22.

however, different memory systems may operate in different operating environments and may have different component parameter offsets, and thus the first system voltage V1 generated by the fixed voltage source in each system may also be different. For example, in different memory systems, the first system voltage V1 may be between 2.5V with minimum variance and 5.7V with maximum variance. In the case where the input logic voltage Vctrl1 has a high potential of 1.2 to 1.98V, if the level shift driver 24 directly shifts the input logic voltage Vctrl1 to a potential close to the first system voltage V1, the pull-up transistor and the pull-down transistor in the level shift driver 24 may be under unbalanced bias. For example, when the first system voltage V1 is at the maximum variation value, for example, 5.7V, and the input logic voltage Vctrl1 is changed from low potential 0V to high potential 1.2V, the pull-up transistor and the pull-down transistor in the level shift driver 24 will turn on simultaneously under unbalanced bias, resulting in poor efficiency of the level shift driver 24. In this case, the level shift driver 24 may need to select the pull-up transistor and the pull-down transistor with appropriate sizes to maintain the circuit function according to the actual operating conditions.

to solve this problem, the voltage control apparatus 200 may further include a fourth power switch 260. The fourth power switch 260 has a first input terminal, a second input terminal and an output terminal. A first input terminal of the fourth power switch 260 may receive the first system voltage V1, a second input terminal of the fourth power switch 260 may be coupled to the output terminal of the first charge pump 210, and an output terminal of the fourth power switch 260 may be coupled to the level shift driver 24.

When the memory system 20 is performing a read operation, the voltage control apparatus 200 can enter a third mode, in which the output terminal of the fourth power switch 260 can output the first application voltage VP1 generated by the first charge pump 210, and the level shift driver 24 can shift the input logic voltage Vctrl1 according to the first application voltage VP 1. In this case, the first application voltage VP1 may be set to be greater than the minimum variation value of the first system voltage V1, for example, 2.5V, and less than the maximum variation value of the first system voltage V1, for example, 5.7V. That is, the first application voltage VP1 may be set to a voltage value between the minimum variation of the first system voltage V1 and the maximum variation of the first system voltage V1, such as, but not limited to, 3.5V between 2.5V and 5.7V.

in this way, the level shift driver 24 can receive the first application voltage VP1 to shift the level of the input logic voltage Vctrl1 to generate the driving control voltage Vctrl2, so that the internal pull-up transistor and pull-down transistor can be in a relatively balanced bias state, thereby increasing the speed of changing the level and reducing the area of the level shift driver 24. That is, through the first charge pump 210 and the fourth power switch 260, the level shift driver 24 can receive the first application voltage VP1 without the problem of poor efficiency caused by the first system voltage V1 having different voltage values in different systems, so that the level shift driver 24 can be implemented by using smaller transistors, thereby reducing the overall required circuit area.

in addition, when the voltage control apparatus 200 is in idle (standby), the first charge pump 210 may stop generating the first application voltage VP1, and the fourth power switch 260 may instead output the first system voltage V1 to the level shift driver 24 to avoid floating the input memory array 22. Furthermore, when the voltage control apparatus 200 is in the first mode and performs the erase operation on the memory cell 22A, or in the second mode and performs the write operation on the memory cell 22A, the first application voltage VP1 generated by the first charge pump 210 is mainly used to provide the high voltage for the erase or write operation, in which case the first application voltage VP1 may be greater than the bias voltage required by the level shift driver 24, so that the fourth power switch 260 may output the first system voltage V1 to the level shift driver 24. That is, when the voltage control apparatus 200 is idle, performing the erase operation, or performing the write operation, the fourth power switch 260 outputs the first system voltage V1 to the level shift driver 24.

In summary, the voltage control apparatus and the memory system provided by the embodiments of the invention can more efficiently utilize the internal charge pump circuit to generate the required application voltage, thereby reducing the circuit area of the charge pump circuit. In addition, when the voltage control device is applied to a memory system, the voltage control device can also generate a proper operating voltage, so that the potential offset driver can more effectively offset the voltage level of the logic control signal, and the circuit area required by the system can be reduced.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.