阅读说明：本技术 片上终端电路及存储器设备 (On-chip termination circuit and memory device ) 是由 刘志拯 于 2020-06-03 设计创作，主要内容包括：本发明提供了一种片上终端电路及存储器设备,片上终端电路包括：信号输入端；接地端；第一晶体管,包括控制端、第一端及第二端,所述控制端及所述第一端与所述信号输入端电连接,所述第二端与所述接地端电连接；第二晶体管,包括控制端、第一端及第二端,所述第一端与所述信号输入端电连接,所述第二端与所述接地端电连接,随着所述信号输入端的电压的变化,所述第一晶体管的电阻的变化趋势与所述第二晶体管的电阻的变化趋势相反。本发明的优点在于,随着所述信号输入端的电压的变化,所述片上终端电路的电阻始终维持在一数值范围内,所述片上终端电路的电阻稳定性高,进而提高存储器设备的信号完整性。(The invention provides an on-chip terminal circuit and a memory device, the on-chip terminal circuit includes: a signal input terminal; a ground terminal; the first transistor comprises a control end, a first end and a second end, wherein the control end and the first end are electrically connected with the signal input end, and the second end is electrically connected with the grounding end; and the second transistor comprises a control end, a first end and a second end, the first end is electrically connected with the signal input end, the second end is electrically connected with the grounding end, and the variation trend of the resistance of the first transistor is opposite to that of the resistance of the second transistor along with the variation of the voltage of the signal input end. The invention has the advantages that the resistance of the on-chip terminal circuit is always maintained in a numerical range along with the change of the voltage of the signal input end, the resistance stability of the on-chip terminal circuit is high, and the signal integrity of the memory device is further improved.)

1. An on-chip terminal circuit, comprising:

a signal input terminal;

a ground terminal;

the first transistor comprises a control end, a first end and a second end, wherein the control end and the first end are electrically connected with the signal input end, and the second end is electrically connected with the grounding end;

and the second transistor comprises a control end, a first end and a second end, the first end is electrically connected with the signal input end, the second end is electrically connected with the grounding end, and the variation trend of the resistance of the first transistor is opposite to that of the resistance of the second transistor along with the variation of the voltage of the signal input end.

2. The on-chip termination circuit of claim 1, wherein the first transistor operates in a saturation region, and the resistance of the first transistor changes in a trend of decreasing with an increase in the voltage of the signal input terminal or increasing with a decrease in the voltage of the signal input terminal.

3. The on-chip termination circuit according to claim 1, wherein the second transistor operates in a linear region, and a resistance of the second transistor changes in a tendency of increasing with an increase in the voltage of the signal input terminal or decreasing with a decrease in the voltage of the signal input terminal.

4. The on-chip termination circuit of claim 3, wherein the control terminal of the second transistor is electrically connected to a supply voltage.

5. The on-chip termination circuit of claim 4, wherein the control terminal of the second transistor is electrically connected to the supply voltage through a transmission gate.

6. The on-chip termination circuit of claim 4, further comprising:

the phase inverter is provided with an input end and an output end, and the input end is electrically connected with the signal input end;

a third transistor having a control terminal, a first terminal and a second terminal, wherein the control terminal is electrically connected to the output terminal of the inverter, the first terminal is electrically connected to the control terminal of the second transistor, and the second terminal is electrically connected to the ground terminal.

7. The on-chip termination circuit of claim 1, wherein the second terminal of the first transistor and the second terminal of the second transistor are electrically connected to the ground terminal through an enable unit, and the enable unit is turned on or off according to a control signal to control the turn-on and turn-off of the second terminal and the ground terminal.

8. The on-chip termination circuit of claim 7, wherein the enable unit is an NMOS transistor.

9. A memory device comprising an on-chip termination circuit, the on-chip termination circuit comprising:

a signal input terminal;

a ground terminal;

the first transistor comprises a control end, a first end and a second end, wherein the control end and the first end are electrically connected with the signal input end, and the second end is electrically connected with the grounding end;

and the second transistor comprises a control end, a first end and a second end, the first end is electrically connected with the signal input end, the second end is electrically connected with the grounding end, and the variation trend of the resistance of the first transistor is opposite to that of the resistance of the second transistor along with the variation of the voltage of the signal input end.

10. The memory device according to claim 9, wherein the first transistor operates in a saturation region, and a resistance of the first transistor changes in a tendency to decrease with an increase in the voltage of the signal input terminal or to increase with a decrease in the voltage of the signal input terminal.

11. The memory device according to claim 9, wherein the second transistor operates in a linear region, and a resistance of the second transistor changes in a tendency of increasing with an increase in the voltage of the signal input terminal or decreasing with a decrease in the voltage of the signal input terminal.

12. The memory device according to claim 11, wherein a control terminal of the second transistor is electrically connected to a power supply voltage.

13. The memory device according to claim 12, wherein the control terminal of the second transistor is electrically connected to the power supply voltage through a transmission gate.

14. The memory device of claim 12, wherein the on-chip termination circuit further comprises:

the phase inverter is provided with an input end and an output end, and the input end is electrically connected with the signal input end;

a third transistor having a control terminal, a first terminal and a second terminal, wherein the control terminal is electrically connected to the output terminal of the inverter, the first terminal is electrically connected to the control terminal of the second transistor, and the second terminal is electrically connected to the ground terminal.

15. The memory device according to claim 9, wherein the second terminal of the first transistor and the second terminal of the second transistor are electrically connected to the ground terminal through an enable unit, and the enable unit is turned on or off according to a control signal to control the turn-on and turn-off of the second terminal and the ground terminal.

16. The memory device of claim 15, wherein the enable unit is an NMOS transistor.

Technical Field

The present invention relates to the field of memories, and in particular, to an on-chip terminal circuit and a memory device.

Background

Memory devices degrade signal integrity due to increases in their capacity and operating speed. For example, as the operating speed of memory devices increases, the bandwidth of data transmitted by the channels that the memory controller connects to the memory devices may increase, which may reduce signal quality. Therefore, On Die Termination (ODT) circuits are used to reduce signal noise and prevent the signal from forming reflections On the circuits.

For memory, signal integrity is critical. Therefore, as the memory operating speed increases, the requirements on the on-chip termination circuit become very strict. For example, according to the LPDDR4 specification, the resistance of the on-chip termination circuit must be within a certain area when the pad voltage is between 10% and 50% of VDDQ.

However, the resistance of the conventional on-chip termination circuit is unstable and cannot meet the demand.

Disclosure of Invention

The present invention provides an on-chip termination circuit and a memory device, which can maintain the resistance of the on-chip termination circuit stable to improve the signal integrity of the memory device.

In order to solve the above problems, the present invention provides an on-chip termination circuit including: a signal input terminal; a ground terminal; the first transistor comprises a control end, a first end and a second end, wherein the control end and the first end are electrically connected with the signal input end, and the second end is electrically connected with the grounding end; and the second transistor comprises a control end, a first end and a second end, the first end is electrically connected with the signal input end, the second end is electrically connected with the grounding end, and the variation trend of the resistance of the first transistor is opposite to that of the resistance of the second transistor along with the variation of the voltage of the signal input end.

Further, the first transistor operates in a saturation region, and the resistance of the first transistor changes in a trend of decreasing with an increase in the voltage of the signal input terminal or increasing with a decrease in the voltage of the signal input terminal.

Further, the second transistor operates in a linear region, and the resistance of the second transistor tends to increase with an increase in the voltage of the signal input terminal or decrease with a decrease in the voltage of the signal input terminal.

Further, the control terminal of the second transistor is electrically connected to a power supply voltage.

Further, the control terminal of the second transistor is electrically connected to the power supply voltage through a transmission gate.

Further, the on-chip termination circuit further includes: the phase inverter is provided with an input end and an output end, and the input end is electrically connected with the signal input end; a third transistor having a control terminal, a first terminal and a second terminal, wherein the control terminal is electrically connected to the output terminal of the inverter, the first terminal is electrically connected to the control terminal of the second transistor, and the second terminal is electrically connected to the ground terminal.

Further, the second terminal of the first transistor and the second terminal of the second transistor are electrically connected to the ground terminal through an enable unit, and the enable unit is turned on or off according to a control signal to control the turn-on and turn-off of the second terminal and the ground terminal.

Further, the enabling unit is an NMOS transistor.

The present invention also provides a memory device comprising an on-chip termination circuit, the on-chip termination circuit comprising: a signal input terminal; a ground terminal; the first transistor comprises a control end, a first end and a second end, wherein the control end and the first end are electrically connected with the signal input end, and the second end is electrically connected with the grounding end; and the second transistor comprises a control end, a first end and a second end, the first end is electrically connected with the signal input end, the second end is electrically connected with the grounding end, and the variation trend of the resistance of the first transistor is opposite to that of the resistance of the second transistor along with the variation of the voltage of the signal input end.

Further, the first transistor operates in a saturation region, and the resistance of the first transistor changes in a trend of decreasing with an increase in the voltage of the signal input terminal or increasing with a decrease in the voltage of the signal input terminal.

Further, the second transistor operates in a linear region, and the resistance of the second transistor tends to increase with an increase in the voltage of the signal input terminal or decrease with a decrease in the voltage of the signal input terminal.

Further, the control terminal of the second transistor is electrically connected to a power supply voltage.

Further, the control terminal of the second transistor is electrically connected to the power supply voltage through a transmission gate.

Further, the on-chip termination circuit further includes: the phase inverter is provided with an input end and an output end, and the input end is electrically connected with the signal input end; a third transistor having a control terminal, a first terminal and a second terminal, wherein the control terminal is electrically connected to the output terminal of the inverter, the first terminal is electrically connected to the control terminal of the second transistor, and the second terminal is electrically connected to the ground terminal.

Further, the second terminal of the first transistor and the second terminal of the second transistor are electrically connected to the ground terminal through an enable unit, and the enable unit is turned on or off according to a control signal to control the turn-on and turn-off of the second terminal and the ground terminal.

Further, the enabling unit is an NMOS transistor.

The on-chip termination circuit has the advantages that with the change of the voltage of the signal input end, the change trend of the resistance of the first transistor is opposite to the change trend of the resistance of the second transistor, and the resistance changes of the first transistor and the second transistor are complementary no matter the voltage of the signal input end is increased or decreased, so that the resistance of the on-chip termination circuit is always within a preset value range, the resistance stability of the on-chip termination circuit is high, and the signal integrity of the memory device is improved.

Drawings

FIG. 1 is a circuit diagram of a first embodiment of an on-chip termination circuit of the present invention;

fig. 2 is a circuit diagram of a second embodiment of the on-chip termination circuit of the present invention.

Detailed Description

Specific embodiments of the on-chip termination circuit and the memory device provided by the present invention are described in detail below with reference to the accompanying drawings.

Generally, for high-speed chips, in order to ensure signal transmission integrity, the on-chip termination resistance value at the interface is required to fluctuate within a small range. For example, according to the LPDDR4 specification, the resistance of the on-chip termination circuit must be within a certain area when the Data (DQ) pad voltage is between 10% and 50% of the supply Voltage (VDDQ), i.e., the resistance of the on-chip termination circuit needs to be stable when the DQ pad voltage varies between 10% and 50% of VDDQ, so that the signal integrity of the memory device can be improved. For faster or wider chip such as DDR5, LPDDR5, etc., the requirements for on-chip termination circuits may be higher. However, for the conventional on-chip termination circuit, the resistance of the on-chip termination circuit is greatly influenced by external factors (such as the influence of pad voltage), and the stability is not sufficient, so that the requirement cannot be met.

Accordingly, an embodiment of the present invention provides an on-chip termination circuit whose resistance remains stable when the DQ pad voltage varies (e.g., in an embodiment, the DQ pad voltage varies between 10% and 50% of VDDQ), thereby improving the signal integrity of the memory device.

Fig. 1 is a circuit diagram of a first embodiment of the on-chip termination circuit of the present invention. Referring to fig. 1, the on-chip termination circuit of the present invention includes a signal input terminal 10, a ground terminal 11, a first transistor M1 and a second transistor M2.

The signal input 10 is for receiving an input signal, for example a voltage signal on a DQ pad.

The first transistor M1 includes a control terminal, a first terminal and a second terminal, the control terminal and the first terminal are electrically connected to the signal input terminal 10, and the second terminal is electrically connected to the ground terminal 11. In this embodiment, the first transistor M1 is an NMOS transistor, and has a first terminal serving as a drain terminal and a second terminal serving as a source terminal. In other embodiments of the present invention, the first transistor M1 may also be a PMOS transistor, with the first terminal being a drain terminal and the second terminal being a source terminal.

The second transistor M2 includes a control terminal, a first terminal electrically connected to the signal input terminal 10, and a second terminal electrically connected to the ground terminal 11. In this embodiment, the second transistor M2 is an NMOS transistor, and has a first terminal serving as a drain terminal and a second terminal serving as a source terminal. In other embodiments of the present invention, the second transistor M2 may also be a PMOS transistor, in which the first terminal is a drain terminal and the second terminal is a source terminal.

It is understood that in some embodiments of the present invention, the first transistor M1 and the second transistor M2 are of the same transistor type, for example, both are NMOS transistors, or both are PMOS transistors.

Wherein, as the voltage of the signal input terminal 10 changes, the resistance of the first transistor M1 changes in a trend opposite to that of the second transistor M2. Specifically, under the same trend of the voltage at the signal input terminal 10, if the resistance of the first transistor M1 is in a decreasing trend, the resistance of the second transistor M2 is in an increasing trend; if the resistance of the first transistor M1 tends to increase, the resistance of the second transistor M2 tends to decrease.

Further, the control terminal and the first terminal of the first transistor M1 are both electrically connected to the signal input terminal 10, that is, the control terminal and the first terminal of the first transistor M1 are shorted, so that the first transistor M1 operates in a saturation region. The resistance of the first transistor M1 has a trend opposite to that of the voltage of the signal input terminal 10. That is, the resistance of the first transistor M1 decreases as the voltage of the signal input terminal 10 increases, or the resistance of the first transistor M1 increases as the voltage of the signal input terminal 10 decreases.

Further, the second transistor M2 operates in a linear region. The resistance of the second transistor M2 has the same tendency as the voltage of the signal input terminal 10. That is, the resistance of the second transistor M2 increases as the voltage of the signal input terminal 10 increases, or the resistance of the second transistor M2 decreases as the voltage of the signal input terminal 10 decreases.

Further, a control terminal of the second transistor M2 is electrically connected to a power supply voltage VDDQ, which drives the second transistor M2 to turn on. Since the power supply voltage VDDQ is substantially maintained stable, the variation trend of the resistance of the second transistor M2 is only related to the variation trend of the voltage of the signal input terminal 10.

In this embodiment, the control terminal of the second transistor M2 is electrically connected to the power supply voltage VDDQ through a transmission gate TG. The on-off of the transmission gate TG controls whether the control end of the second transistor M2 is electrically connected with the power supply voltage VDDQ, and improves the stability of the electrical connection.

In other embodiments of the present invention, the control terminal of the second transistor M2 may also be electrically connected to the power supply voltage VDDQ through another switch unit, such as an NMOS transistor or a PMOS transistor. When the switch unit is turned on, the control terminal of the second transistor M2 is electrically connected to the power supply voltage VDDQ, and when the switch unit is turned off, the control terminal of the second transistor M2 is disconnected from the power supply voltage VDDQ.

In this embodiment, the trend of the resistance of the first transistor M1 is opposite to the trend of the voltage of the signal input terminal 10, and the trend of the resistance of the second transistor M2 is the same as the trend of the voltage of the signal input terminal 10, but it can be understood that, in other embodiments of the present invention, the trend of the resistance of the first transistor M1 is the same as the trend of the voltage of the signal input terminal 10, and the trend of the resistance of the second transistor M2 is opposite to the trend of the voltage of the signal input terminal 10, so as to satisfy the requirement that the trend of the resistance of the first transistor M1 is opposite to the trend of the resistance of the second transistor M2 with the change of the voltage of the signal input terminal 10.

Further, in the present embodiment, the second terminal of the first transistor M1 and the second terminal of the second transistor M2 are not directly electrically connected to the ground terminal 11, but are electrically connected to the ground terminal 11 through an enable unit M4. The enable unit M4 is turned on or off according to a control signal to control the turn-on and turn-off of the second terminal of the first transistor M1 and the second terminal of the second transistor M2 with the ground terminal 11.

Optionally, the enable unit M4 is an NMOS transistor, a control terminal of the NMOS transistor is electrically connected to the control module, a drain terminal of the NMOS transistor is electrically connected to the second terminal of the first transistor M1 and the second terminal of the second transistor M2, and a source terminal of the NMOS transistor is electrically connected to the ground terminal 11. The control terminal of the NMOS transistor drives the NMOS transistor to be turned on or off according to a control signal EN sent by the control module, thereby controlling the second terminal of the first transistor M1 and the second terminal of the second transistor M2 to be turned on or off with the ground terminal 11. In other embodiments of the present invention, the enabling unit M4 may also be a PMOS transistor, and a control terminal of the PMOS transistor drives the PMOS transistor to be turned on or off according to a control signal EN sent by a control module, so as to control the second terminal of the first transistor M1 and the second terminal of the second transistor M2 to be turned on or off with the ground terminal 11.

In the present invention, as the voltage of the signal input terminal 10 changes, the trend of the resistance of the first transistor M1 is opposite to the trend of the resistance of the second transistor M2, and then no matter the voltage of the signal input terminal 10 becomes larger or smaller, the changes of the resistances of the first transistor M1 and the second transistor M2 are complementary, so that the changes of the resistances of the first transistor M1 and the second transistor M2 can be approximately offset, the resistance of the on-chip termination circuit is always maintained within a preset value range, the resistance stability of the on-chip termination circuit is high, and the signal integrity of the memory device is further improved.

In practicing the first embodiment of the present invention, the inventors have found that the resistance of the on-chip termination circuit may in some cases be outside a predetermined range of values. As a result of research, the inventors found that this situation occurs because the resistance variation amplitude of the second transistor M2 is larger than that of the first transistor M1 as the voltage of the signal input terminal 10 varies, which makes the variation in resistance of the first transistor M1 unable to offset the variation in resistance of the second transistor M2, so that the resistance of the on-chip termination circuit increases or decreases and is not maintained within a preset value range.

In order to solve the above problem, a second embodiment of the present invention provides an on-chip termination circuit, which is capable of slowing down the variation trend of the resistance of the second transistor M2, wherein the variation range of the resistance of the second transistor M2 is reduced, so that the resistance of the on-chip termination circuit is maintained within a preset value range. Fig. 2 is a circuit diagram of a second embodiment of the on-chip termination circuit of the present invention. Referring to fig. 2, the second embodiment is different from the first embodiment in that in the second embodiment, the control terminal of the second transistor M2 is not only connected to the voltage VDDQ, but also connected to the signal output terminal 10 through the inverter 12 and the third transistor M3. The signal output terminal 10 and the power supply voltage VDDQ commonly control the control terminal of the second transistor M2. The concrete description is as follows:

the on-chip termination circuit includes an inverter 12 and a third transistor M3.

The inverter 12 has an input and an output. The input terminal is electrically connected to the signal input terminal 10, and the output terminal is electrically connected to the control terminal of the third transistor M3.

The third transistor M3 has a control terminal, a first terminal and a second terminal. The control terminal is electrically connected to the output terminal of the inverter 12, the first terminal is electrically connected to the control terminal of the second transistor M2, and the second terminal is electrically connected to the ground terminal 11. The trend of the voltage at the signal input terminal 10 is transmitted to the control terminal of the second transistor M2 through the inverter 12 and the third transistor M3, so that the voltage at the control terminal of the second transistor M2 has the same trend with the change of the voltage at the signal input terminal 10.

In the second embodiment, the variation trend of the resistance of the second transistor M2 is opposite to the variation trend of the voltage at the control end of the second transistor M2, and is the same as the variation trend of the voltage at the signal input end 10, so that the variation trend of the resistance of the second transistor M2 can be slowed down, the variation range of the resistance of the second transistor M2 can be reduced, the resistance variation of the second transistor M2 and the resistance variation range of the first transistor M1 can be equalized, the variation of the resistance of the first transistor M1 can approximately offset the variation of the resistance of the second transistor M2, and the resistance of the on-chip termination circuit can be maintained within a preset value range.

For example, if the voltage at the signal input terminal 10 is decreasing, the voltage at the signal input terminal 10 is transmitted to the control terminal of the second transistor M2 through the inverter 12 and the third transistor M3, and then the voltage at the control terminal of the second transistor M2 is decreasing, and the resistance of the second transistor M2 is increasing. Since the signal transmission terminal 10 is electrically connected to the first terminal of the second transistor M2, the voltage of the first terminal of the second transistor M2 has the same trend as the voltage of the signal input terminal 10, i.e., the trend of the voltage of the first terminal of the second transistor M2 is also reduced. Under the synergistic effect of the voltage variation trends of the control terminal and the first terminal of the second transistor M2, the variation trend of the resistance of the second transistor M2 is the same as that of the voltage of the signal input terminal 10, and the variation amplitude thereof is reduced compared with the first embodiment, and the resistance variation of the second transistor M2 and the resistance variation amplitude of the first transistor M1 tend to be equal, so that the variation of the resistance of the first transistor M1 can approximately offset the variation of the resistance of the second transistor M2, and the resistance of the on-chip termination circuit is maintained within a preset value range.

For example, if the voltage at the signal input terminal 10 changes in a trend of increasing, the voltage at the signal input terminal 10 is transferred to the control terminal of the second transistor M2 through the inverter 12 and the third transistor M3, and then the voltage at the control terminal of the second transistor M2 changes in a trend of increasing, and the resistance of the second transistor M2 changes in a trend of decreasing. Since the signal transmission terminal 10 is electrically connected to the first terminal of the second transistor M2, the voltage of the first terminal of the second transistor M2 has the same trend as the voltage of the signal input terminal 10, i.e., the trend of the voltage of the first terminal of the second transistor M2 is also increased. The control terminal of the second transistor M2 cooperates with the voltage variation trend of the first terminal, so that the variation trend of the resistance of the second transistor M2 is the same as the variation trend of the voltage of the signal input terminal 10, and the variation range thereof is reduced compared with the first embodiment, and the variation of the resistance of the second transistor M2 is equal to the variation range of the resistance of the first transistor M1, so that the variation of the resistance of the first transistor M1 can approximately offset the variation of the resistance of the second transistor M2, so that the resistance of the on-chip termination circuit is maintained within the preset value range.

In this embodiment, the third transistor M3 is an NMOS transistor, but in other embodiments of the invention, the third transistor M3 may also be a PMOS transistor. It is understood that, in some embodiments of the present invention, the third transistor M3 and the second transistor M2 are transistors of the same type, for example, both NMOS transistors or both PMOS transistors.

The above description is only one method for slowing down the variation trend of the resistance of the second transistor M2 in this embodiment. It will be appreciated that other methods of achieving this are possible and the invention is not limited in this regard.

The invention also provides a memory device. The memory device comprises the on-chip termination circuit. The resistance of the on-chip terminal circuit is basically maintained within a preset value along with the change of the voltage of the signal input end, and the resistance stability of the on-chip terminal circuit is high, so that the memory device has high signal integrity, and the storage performance of the memory device is greatly improved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.