# Patent

## Title
Replica bit-line control circuit

## Abstract

The present invention discloses a replica bit-line circuit, comprising a replica unit, the 1st inverter, the 2nd inverter, the 3rd inverter, the 4th inverter, the 5th inverter, the 6th inverter, the 7th inverter, the 8th inverter, the 9th inverter, the 1st NAND gate, the 2nd NAND gate, the 3rd NAND gate, the 1st NOR gate, the 2nd NOR gate and the 1st PMOS tube; the 2nd NOR gate is provided with the 1st input terminal, the 2nd input terminal, a set terminal and an output terminal; advantages of the present invention are stated as follows: It can inhibit feedback oscillation incurred by replica bit-line and replica wordline signal to obtain accurate wordline control signal; it can save switching power consumption of memory array by 53.7% under the power voltage of 1.2V.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of China application serial no. 201610585441.1, filed on Jul. 21, 2016. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
FIELD OF THE INVENTION
The present invention is related to a control circuit, in particular to a replica bit-line control circuit.
BACKGROUND
Presently, SARM power consumption is mainly reduced by introducing replica bit-line control circuit 100 to SRAM to produce sensitivity amplifier enabling signals SAE and wordline control signals WL. The schematic block diagram is as shown in FIG. 1. A replica bit-line control circuit is proposed by Amrutur B S, Horowitz M. in A replica technique for wordline and sense control in low-power SRAM's [J]. IEEE Journal of Solid-State Circuits, 1998, 33(8): 1208, which is as shown in FIG. 2. When sense amplifier enabling signals are valid, wordline control signal WL of the replica bit-line control circuit is to be cut off through time delay by the inverter S9 and NOR gate D1, which may further result in unnecessary voltage loss; furthermore, a feedback oscillation is to be produced when chip selection signal BS is set at high electrical level for a prolonged time, which may continuously charge and discharge the capacitor of replica wordline signal RWL and replica bit-line RBL to the extent of incurring unnecessary power consumption; the feedback oscillation waveform is as shown in FIG. 3.
SUMMARY OF THE INVENTION
The technical issue to be settled by the present invention is to provide a replica bit-line control circuit that can significantly reduce SRAM power consumption.
Technical solution used by the present invention to settled aforesaid technical issues is stated as follows: A replica bit-line control circuit, comprising a replica unit, the 1st inverter, the 2nd inverter, the 3rd inverter, the 4th inverter, the 5th inverter, the 6th inverter, the 7th) inverter, the 8th inverter and the 9th inverter, the 1st NAND gate, the 2nd NAND gate, the 3rd NAND gate, the 1st NOR gate, the 2nd NOR gate and the 1st PMOS tube; the 1st NAND gate, the 2nd NAND gate, the 3rd NAND gate and the 1st NOR gate are provided with the 1st input terminal, the 2nd input terminal and an output terminal respectively; the 2nd NOR gate is provided with the 1st input terminal, the 2nd input terminal, a set terminal and an output terminal; the said replica unit comprises a drive unit and numerous load units; the said drive unit is provided with an input/output terminal, a complementary input/output terminal and a control terminal; the said load unit is provided with an input/output terminal and a complementary input/output terminal; input/output terminal of the said drive unit is connected to input/output terminal of numerous load units, and the connecting line is the replica bit-line of the said replica unit; complementary input/output terminal of the said drive unit is connected to complementary input/output terminal of numerous load units; the 1st input terminal of the 1st NAND gate is the 1st input terminal of the said replica bit-line control circuit, used to receive global wordline control signals; the 1st input terminal of the 2nd NAND gate is connected to the input terminal of the 3rd NAND gate, and the connecting terminal is the 2nd input terminal of the said replica bit-line control circuit, used to receive chip selection signals; the 2nd input terminal of the 2nd NAND gate is connected to the input terminal of the 9th inverter, and the connecting terminal is the 3rd input terminal of the said replica bit-line control circuit, used to receive writing control signals; output terminal of the 2nd NAND gate is connected to the 1st input terminal of the 2nd NOR gate; output terminal of the 9th inverter is connected to the 2nd input terminal of the 3rd NAND gate; output terminal of the 3rd NAND gate and input terminal of the 8th inverter are connected to the grid of the PMOS tube; output terminal of the 8th inverter is connected to the 1st input terminal of the 1st NOR gate; output terminal of the 1st NOR gate and the 2nd input terminal of the 2nd NOR gate are connected to the control terminal of the said drive unit; set terminal of the 2nd NOR gate, drain of the 1st PMOS tube and input terminal of the 1st inverter are connected to the replica bit-line of the said replica unit; source of the 1st PMOS tube is connected to the power supply; output terminal of the 2nd NOR gate is connected to the input terminal of the 6th inverter; output terminal of the 6th inverter is connected to the 2nd input terminal of the 1st NAND gate; output terminal of the 1st NAND gate is connected to the input terminal of the 7th inverter; output terminal of the 7th inverter is the 1st output terminal of the said replica bit-line, which is used to output wordline control signals; output terminal of the 1st inverter and input terminal of the 2nd inverter are connected to the 2nd input terminal of the 1st NOR gate; output terminal of the 2nd inverter is connected to the input terminal of the 3rd inverter; output terminal of the 3rd inverter is connected to the input terminal of the 4th inverter; output terminal of the 4th inverter is connected to the input terminal of the 5th inverter; output terminal of the 5th inverter is the 2nd output terminal of the said replica bit-line control circuit, used to output sense amplifier enabling signals; the 2nd NOR gate comprises the 2nd PMOS tube, the 3rd PMOS tube, the 4th PMOS tube, the 1st NMOS tube, the 2nd NMOS tube and the 3rd NMOS tube; source of the 2nd PMOS tube and the 4th PMOS tube is connected to the power supply respectively; drain of the 2nd PMOS tube is connected to the source of the 3rd PMOS tube; grid of the 2nd PMOS tube is connected to the grid of the 2nd NMOS tube, and the connecting terminal is the 1st input terminal of the 2nd NOR gate; grid of the 3rd PMOS tube is connected to the grid of the 1st NMOS tube, and the connecting terminal is the 2nd input terminal of the 2nd NOR gate; drain of the 3rd PMOS tube, the 1st NMOS tube and the 4th PMOS tube is connected to the drain of the 2nd NMOS tube, and the connecting terminal is the output terminal of the 2nd NOR gate; source of the 1st NMOS tube and drain of the 3rd NMOS tube are connected to the source of the 2nd NMOS tube; grid of the 3rd NMOS tube is connected to the grid of the 4th PMOS tube, and the connecting terminal is the set terminal of the 2nd NOR gate; source of the 3rd NMOS tube is grounded.
The said load unit comprises the 5th PMOS tube, the 6th PMOS tube; the 4th NMOS tube, the 5th NMOS tube, the 6th NMOS tube and the 7th NMOS tube; source of the 5th PMOS tube, drain of the 5th PMSO tube, drain of the 4th NMOS tube, drain of the 6th NMOS tube, source of the 6th PMOS tube; grid of the 6th PMOS tube and grid of the 5th NMOS tube are connected to power supply respectively; grid of the 5th PMOS tube, grid of the 4th NMOS tube, drain of the 6th PMOS tube and drain of the 5th NMOS tube are connected to the drain of the 7th NMOS tube; source of the 4th NMOS tube, source of the 5th NMOS tube, grid of the 6th NMOS tube and grid of the 7th NMOS tube are grounded respectively; source of the 6th NMOS tube is the output terminal of the said load unit; source of the 7th NMOS tube is the complementary input/output terminal of the said load unit. Structure of the circuit is similar to that of the memory unit in the memory array, which can effectively guard against impact from such factors as threshold voltage, power voltage and ambient temperature; furthermore, as source of the 5th PMOS tube, drain of the 4th NMOS tube and drain of the 6th NMOS tube are connected to the power supply, it can effectively accommodate the slowest discharge of replica bit-line under the impact of leakage current.
The said drive unit comprises the 7th PMOS tube, the 8th PMOS tube, the 8th NMOS tube, the 9th NMOS tube, the 10th NMOS tube and the 11th NMOS tube; source of the 7th PMOS tube, grid of the 7th PMOS tube, grid of the 8th NMOS tube, drain of the 8th PMOS tube, source of the 8th PMOS tube, drain of the 9th NMOS tube and drain of the 11th NMOS tube are connected to the power supply respectively; drain of the 7th PMOS tube, drain of the 8th NMOS tube, drain of the 10th NMOS tube and grid of the 8th PMOS tube are connected to the grid of the 9th NMOS tube; source of the 8th NMOS tube and source of the 9th NMOS tube are grounded respectively; grid of the 10th NMOS tube is connected to the grid of the 11th NMOS tube, and the connecting terminal is the control terminal of the said drive unit; source of the 10th NMOS tube is the input/output terminal of the said drive unit; source of the 11th NMOS tube is the complementary input/output terminal of the said drive unit. Structure of the circuit is similar to that of the memory unit in the memory array, which can effectively guard against impact from such factors as threshold voltage, power voltage and ambient temperature; furthermore, as drain of the 7th PMOS tube, drain of the 8th NMOS tube and drain of the 10th NMOS tube are grounded, it can simulate discharge of the bit-line in the memory array to the ground.
As compared with prior art, the present invention has the following advantages: When sense amplifier enabling signals are valid, it can ensure timely cutoff of wordline control signals through balancing time delay for on/off of wordline control signals to minimize switching power consumption as incurred by unnecessary discharging by the memory array pairs. Moreover, it makes use of the 2nd NAND gate, the 3rd NAND gate and the 9th inverter to decompose chip selection signals to generate clock reading control signals in substitution of replica wordline signal control for charging of replica bit-line; it can effectively inhibit feedback oscillation incurred by replica bit-line and replica wordline signals to obtain accurate and stable wordline control signals for the purpose of reducing SRAM power consumption; as indicated comparison between the present invention and replica bit-line control circuit as applied to fully customized 2 Mb SRAM circuit based on the technique of SMIC 65 nm CMOS, the present invention can save the switching power consumption of memory array by 53.7% under the power voltage of 1.2V.



DESCRIPTION OF DRAWINGS
FIG. 1 is the structural block diagram for SRAM of existing replica bit-line control circuit;
FIG. 2 is the structural diagram for existing replica bit-line control circuit;
FIG. 3 is the feedback oscillation diagram for existing replica bit-line control circuit;
FIG. 4 is the structural diagram for the present invention;
FIG. 5 is the circuit diagram for the 2nd NOR gate of the present invention;
FIG. 6 is the circuit diagram for the load unit of the present invention;
FIG. 7 is the circuit diagram for the drive unit of the present invention;
FIG. 8 is the structural block diagram for SRAM of the present invention;
FIG. 9 is the signal timing diagram for the present invention



DESCRIPTION OF EMBODIMENTS
The present invention is further described as follows in combination with drawings and embodiments:
Embodiment: As shown in FIG. 4, a replica bit-line control circuit, comprising a replica unit 10, a 1st inverter S1, a 2nd inverter S2, a 3rd inverter S3, a 4th inverter S4, a 5th inverter S5, a 6th inverter S6, a 7th inverter S7, a 8th inverter S8 and a 9th inverter S9, a 1st NAND gate B1, a 2nd NAND gate B2, a 3rd NAND gate B3, a NOR gate D1, a 2nd NOR gate D2 and a PMOS tube P1. The 1st NAND gate B1, the 2nd NAND gate B2, the 3rd NAND gate B3 and the 1st NOR gate D1 are provided with the 1st input terminal, the 2nd input terminal and an output terminal respectively. The 2nd NOR gate B2 is provided with the 1st input terminal, the 2nd input terminal, a set terminal and an output terminal. The said replica unit 10 comprises a drive unit 10-1 and a plurality of load units 10-2. The said drive unit 10-1 is provided with an input/output terminal, a complementary input/output terminal and a control terminal. Each of the said load units 10-2 is provided with an input/output terminal and a complementary input/output terminal; input/output terminal of the said drive unit 10-1 is connected to input/output terminal of the plurality of load units 10-2, and the connecting line is the replica bit-line RBL of the said replica unit 10; the complementary input/output terminal of the said drive unit 10-1 is connected to complementary input/output terminal of the load units 10-2; the 1st input terminal of the 1st NAND gate B1 is the 1 input terminal of the said replica bit-line control circuit, used to receive global wordline control signal GWL; the 1st input terminal of the 2nd NAND gate B2 is connected to the 1st input terminal of the 3rd NAND gate B3, and the connecting terminal is the 2nd input terminal of the said replica bit-line control circuit, used to receive chip selection signal BS; the 2nd input terminal of the 2nd NAND gate B2 is connected to the input terminal of the 9th inverter S9, and the connecting terminal is the 3rd input terminal of the said replica bit-line control circuit, used to receive writing control signal WEN; output terminal of the 2nd NAND gate B2 is connected to the 1st input terminal of the 2nd NOR gate D2; output terminal of the 9th inverter S9 is connected to the 2nd input terminal of the 3rd NAND gate B3; output terminal of the 3rd NAND gate B3 and input terminal of the 8th inverter S8 are connected to the grid of the 1st PMOS tube P1; output terminal of the 8th inverter S8 is connected to the input terminal of the 1st NOR gate D1; output terminal of the 1st NOR gate D1 and the 2nd input terminal of the 2nd NOR gate D2 are connected to the control to terminal of the said drive unit 10-1; set terminal of the 2nd NOR gate D2, drain of the 1st PMOS tube P1 and input terminal of the 1st inverter S1 are connected to the replica bit-line of the said replica unit 10; source of the 1st PMOS tube P1 is connected to the power supply VDD; output terminal of the 2nd NOR gate D2 is connected to the input terminal of the 6th inverter S6; output terminal of the 6th inverter S6 is connected to the 2nd input terminal of the 1st NAND gate B1; output terminal of the 1st NAND gate B1 is connected to the input terminal of the 7th inverter S7; output terminal of the 7th inverter S7 is the 1st output terminal of the said replica bit-line, which is used to output wordline control signal WL; output terminal of the 1st inverter S1 and input terminal of the 2nd inverter S2 are connected to the 2nd input terminal of the 1st NOR gate D1; output terminal of the 2nd inverter S2 is connected to the input terminal of the 3rd inverter S3; output terminal of the 3rd inverter S3 is connected to the input terminal of the 4th inverter S4; output terminal of the 4th inverter S4 is connected to the input terminal of the 5th inverter S5; output terminal of the 5th inverter S5 is the 2nd output terminal of the said replica bit-line control circuit, used to output sense amplifier enabling signal SAE;
As shown in FIG. 5, the 2nd NOR gate D2 comprises a 2nd PMOS tube P2, a 3rd PMOS tube P3, a 4th PMOS tube P4, a 1st NMOS tube N1, a 2nd NMOS tube N2 and a 3rd NMOS tube N3; source of the 2nd PMOS tube P2 and the 4th PMOS tube P4 is connected to the power supply VDD respectively; drain of the 2nd PMOS tube P2 is connected to the source of the 3rd PMOS tube P3; grid of the 2nd PMOS tube P2 is connected to the grid of the 2nd NMOS tube N2, and the connecting terminal is the 1st input terminal of the 2nd NOR gate D2; grid of the 3rd PMOS tube P3 is connected to the grid of the 1st NMOS tube N1, and the connecting terminal is the 2nd input terminal of the 2nd NOR gate D2; drain of the 3rd PMOS tube P3, the 1st NMOS tube N1 and the 4th PMOS tube P4 is connected to the drain of the 2nd NMOS tube N2, and the connecting terminal is the output terminal of the 2nd NOR gate D2; source of the NMOS tube N1 and drain of the 3rd NMOS tube N3 are connected to the source of the 2nd NMOS tube N2; grid of the 3rd NMOS tube N3 is connected to the grid of the 4th PMOS tube P4, and the connecting terminal is the set terminal of the 2nd NOR gate D2; source of the 3rd NMOS tube N3 is grounded VSS.
As shown in FIG. 6, each of the load unit 10-2 in this embodiment comprises a 5th PMOS tube P5, a 6th PMOS tube P6, a 4th NMOS tube N4, a 5th NMOS tube N5, a 6th NMOS tube N6 and a 7th NMOS tube N7. A source of the 5th PMOS tube P5, a drain of the 5th PMSO tube P5, a drain of the 4th NMOS tube N4, a drain of the 6th NMOS tube N6, a source of the 6th PMOS tube P6, a grid of the 6th PMOS tube P6 and a grid of the 5th NMOS tube N5 are connected to power supply VDD respectively. A grid of the 5th PMOS tube P5, a grid of the 4th NMOS tube N4, a drain of the 6th PMOS tube P6 and a drain of the 5th NMOS tube N5 are connected to a drain of the 7th NMOS tube N7. A source of the 4th NMOS tube N4, a source of the 5th NMOS tube N5, a grid of the 6th NMOS tube N6 and a grid of the 7th NMOS tube N7 are grounded VSS respectively. A source of the 6th NMOS tube N6 is the output terminal of the said load unit 10-2. A source of the 7th NMOS tube N7 is the complementary input/output terminal of the said load unit 10-2.
As shown in FIG. 7, the drive unit 10-1 in this embodiment comprises a 7th PMOS tube P7, a 8th PMOS tube P8, a 8th NMOS tube N8, a 9th NMOS tube N9, a 10th NMOS tube N10 and a 11th NMOS tube N11. Source of the 7th PMOS tube P7, grid of the 7th PMOS tube P7, grid of the 8th NMOS tube N8, drain of the 8th PMOS tube P8, source of the 8th PMOS tube P8, drain of the 9th NMOS tube N9 and drain of the 11th NMOS tube N11 are connected to the power supply VDD respectively; drain of the 7th PMOS tube P7, drain of the 8th NMOS tube N8, drain of the 10th NMOS tube N10 and grid of the 8th PMOS tube P8 are connected to the grid of the 9th NMOS tube N9; source of the 8th NMOS tube N8 and source of the 9th NMOS tube N9 are grounded VSS respectively; grid of the 10th NMOS tube N10 is connected to the grid of the 11th NMOS tube N11, and the connecting terminal is the control terminal of the said drive unit 10-1; source of the 10th NMOS tube N10 is the input/output terminal of the said drive unit 10-1; source of the 11th NMOS tube N11 is the complementary input/output terminal of the said drive unit 10-1.
In this embodiment, the 1st inverter S1, the 2nd inverter S2, the inverter S3, the 4th inverter S4, the 5th inverter S5, the 6th inverter S6, the 7th inverter S7, the 8th inverter S8, the 9th inverter S9, the 1st NAND gate B1, the 2nd NAND gate B2, the 3rd NAND gate B3 and the 1st NOR gate D1 are well-established products of prior arts.
Wiring block diagram for the replica bit-line control circuit 1 of the present invention as applied to SRAM is as shown in FIG. 8.
Working principle of the replica bit-line control circuit 1 of the present invention is stated as follows: writing clock control signal WCLK at the beginning of writing operation can directly control the wordline enabling signal WLEN to determine on/off of the wordline control signal of memory array 2 in together with global wordline control signal. For reading operation, signal timing for the replica bit-line control circuit 1 of the present invention is as shown in FIG. 9; wherein, BL and BLB represent a bit-line pair used for charging in the memory array; prior to the commencement of reading cycle, reading clock control signal RCLK is to be maintained at a low electrical level; whereas replica bit-line of the replica unit 10 RBL is to be set at a high electrical level; replica wordline signal RWL, wordline control signal WL and sense amplifier enabling signal SAE are to be set at a low electrical level; at the beginning of reading operation, reading clock control signal RCLK and replica wordline signal RWL are to be set at a high electrical level to control discharging of line capacitor of replica bit-line RBL by the replica unit 10; meanwhile, global wordline control signal GWL is to be set at a high electrical level; replica wordline signal RWL makes use of the 2nd NOR gate D2, the 6th inverter S6, the 1st NAND gate B1 and the 7th inverter S7 to generate valid wordline control signal WL to control discharging of the bit-line BL and BLB by memory unit of the memory array 2. When replica bit-line is set at a low electrical level, sense amplifier enabling signal SAE is to be set at a high electrical level to turn on the sense amplifier 3 following time delay of the 1st inverter S1 ̃the 5th inverter S5; as the 2nd NOR gate D2 is controlled by replica bit-line RBL of the replica unit 10, on/off of wordline control signal WL is not to be determined by replica wordline signal RWL; once replica bit-line RBL of the replica unit 10 is set at a high electrical level, it is applicable to make use of the 2nd NOR gate, the 6 inverter S6, the 1st NAND gate B1 and the 7th inverter S7 to turn off wordline control signal WL, eliminate the time delay incurred by the 1st inverter S1 and the 1st NOR gate D1, and make the opening time Tpulse,WL of wordline control signal WL equal to the discharging time Trbl of replica bit-line RBL. As a result, wordline control signal WL can be turned off in time to prevent unnecessary power consumption, and significantly reduce SRAM power consumption when the sense amplifier 3 is turned on.

## Claims

1. A replica bit-line control circuit, comprising: a replica unit, a 1st inverter, a 2nd inverter, a 3rd inverter, a 4th inverter, a 5th inverter, a 6th inverter, a 7th inverter, a 8th inverter and a 9th inverter, a 1st NAND gate, a 2nd NAND gate, a 3rd NAND gate, a 1st NOR gate, a 2nd NOR gate and a 1st PMOS tube,
wherein the 1st NAND gate, the 2nd NAND gate, the 3rd NAND gate and the 1st NOR gate are provided with a 1st input terminal, a 2nd input terminal and an output terminal respectively; the 2nd NOR gate is provided with a 1st input terminal, a 2nd input terminal, a set terminal and an output terminal; the said replica unit comprises a drive unit and a plurality of load units; the said drive unit is provided with an input/output terminal, a complementary input/output terminal and a control terminal; each of the said load units is provided with an input/output terminal and a complementary input/output terminal; the input/output terminal of the said drive unit is connected to the input/output terminal of the plurality of load units, and the connecting line is the replica bit-line of the said replica unit; wherein the complementary input/output terminal of the said drive unit is connected to the complementary input/output terminal of the plurality of load units; the 1st input terminal of the 1st NAND gate is a 1st input terminal of the said replica bit-line control circuit, used to receive global wordline control signals; the 1st input terminal of the 2nd NAND gate is connected to the 1st input terminal of the 3rd NAND gate, and the connecting terminal is a 2nd input terminal of the said replica bit-line control circuit, used to receive chip selection signals; the 2nd input terminal of the 2nd NAND gate is connected to an input terminal of the 9th inverter, and the connecting terminal is the 3rd input terminal of the said replica bit-line control circuit, used to receive writing control signals; the output terminal of the 2nd NAND gate is connected to the 1st input terminal of the 2nd NOR gate; an output terminal of the 9th inverter is connected to the 2nd input terminal of the 3rd NAND gate; the output terminal of the 3rd NAND gate and an input terminal of the 8th inverter are connected to a grid of the 1st PMOS tube; an output terminal of the 8th inverter is connected to the 1st input terminal of the 1st NOR gate; the output terminal of the 1st NOR gate and the 2nd input terminal of the 2nd NOR gate are connected to the control terminal of the said drive unit; the set terminal of the 2nd NOR gate, an drain of the 1st PMOS tube and an input terminal of the 1st inverter are connected to the replica bit-line of the said replica unit; a source of the 1st PMOS tube is connected to a power supply; the output terminal of the 2nd NOR gate is connected to the input terminal of the 6th inverter; an output terminal of the 6th inverter is connected to the 2nd input terminal of the 1st NAND gate; the output terminal of the 1st NAND gate is connected to an input terminal of the 7th inverter; an output terminal of the 7th inverter is the 1st output terminal of the said replica bit-line, which is used to output wordline control signals; an output terminal of the 1st inverter and an input terminal of the 2nd inverter are connected to the 2nd input terminal of the 1st NOR gate; an output terminal of the 2nd inverter is connected to an input terminal of the 3rd inverter; an output terminal of the 3rd inverter is connected to an input terminal of the 4th inverter; an output terminal of the 4th inverter is connected to an input terminal of the 5th inverter; an output terminal of the 5th inverter is a 2nd output terminal of the said replica bit-line control circuit, used to output sense amplifier enabling signals;
wherein the 2nd NOR gate comprises a 2nd PMOS tube, a 3rd PMOS tube, a 4th PMOS tube, a 1st NMOS tube, a 2nd NMOS tube and a 3rd NMOS tube; a source of each of the 2nd PMOS tube and the 4th PMOS tube is connected to the power supply respectively; a drain of the 2nd PMOS tube is connected to a source of the 3rd PMOS tube; a grid of the 2nd PMOS tube is connected to a grid of the 2nd NMOS tube, and the connecting terminal is the 1st input terminal of the 2nd NOR gate; a grid of the 3rd PMOS tube is connected to a grid of the 1st NMOS tube, and the connecting terminal is the 2nd input terminal of the 2nd NOR gate; a drain of each of the 3rd PMOS tube, the 1st NMOS tube and the 4th PMOS tube is connected to a drain of the 2nd NMOS tube, and the connecting terminal is the output terminal of the 2nd NOR gate; a source of the 1st NMOS tube and a drain of the 3rd NMOS tube are connected to a source of the 2nd NMOS tube; a grid of the 3rd NMOS tube is connected to a grid of the 4th PMOS tube, and the connecting terminal is the set terminal of the 2nd NOR gate; a source of the 3rd NMOS tube is grounded.

2. The replica bit-line control circuit according to claim 1, wherein the said load unit comprises a 5th PMOS tube, a 6th PMOS tube; a 4th NMOS tube, a 5th NMOS tube, a 6th NMOS tube and a 7th NMOS tube; a source of the 5th PMOS tube, a drain of the 5th PMSO tube, a drain of the 4th NMOS tube, a drain of the 6th NMOS tube, a source of the 6th PMOS tube, a grid of the 6th PMOS tube and a grid of the 5th NMOS tube are connected to the power supply respectively; a grid of the 5th PMOS tube, a grid of the 4th NMOS tube, a drain of the 6th PMOS tube and a drain of the 5th NMOS tube are connected to a drain of the 7th NMOS tube; a source of the 4th NMOS tube, a source of the 5th NMOS tube, a grid of the 6th NMOS tube and a grid of the 7th NMOS tube are grounded respectively; a source of the 6th NMOS tube is the output terminal of the said load unit; a source of the 7th NMOS tube is the complementary input/output terminal of the said load unit.

3. The replica bit-line control circuit according to claim 1, wherein the said drive unit comprises a 7th PMOS tube, a 8th PMOS tube, a 8th NMOS tube, a 9th NMOS tube, a 10th NMOS tube and a 11th NMOS tube; a source of the 7th PMOS tube, a grid of the 7th PMOS tube, a grid of the 8th NMOS tube, a drain of the 8th PMOS tube, a source of the 8th PMOS tube, a drain of the 9th NMOS tube and a drain of the 11th NMOS tube are connected to the power supply respectively; a drain of the 7th PMOS tube, a drain of the 8th NMOS tube, a drain of the 10th NMOS tube and a grid of the 8th PMOS tube are connected to a grid of the 9th NMOS tube; a source of the 8th NMOS tube and a source of the 9th NMOS tube are grounded respectively; a grid of the 10th NMOS tube is connected to a grid of the 11th NMOS tube, and the connecting terminal is the control terminal of the said drive unit; a source of the 10th NMOS tube is the input/output terminal of the said drive unit; a source of the 11th NMOS tube is the complementary input/output terminal of the said drive unit.