WO2006062113A1 - 磁気メモリセルの読出し装置 - Google Patents
磁気メモリセルの読出し装置 Download PDFInfo
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- WO2006062113A1 WO2006062113A1 PCT/JP2005/022425 JP2005022425W WO2006062113A1 WO 2006062113 A1 WO2006062113 A1 WO 2006062113A1 JP 2005022425 W JP2005022425 W JP 2005022425W WO 2006062113 A1 WO2006062113 A1 WO 2006062113A1
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- magnetoresistive
- memory device
- voltage
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
- G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
- G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
- G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
- G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
- G11C11/165—Auxiliary circuits
- G11C11/1653—Address circuits or decoders
- G11C11/1655—Bit-line or column circuits
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
- G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
- G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
- G11C11/165—Auxiliary circuits
- G11C11/1659—Cell access
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
- G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
- G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
- G11C11/165—Auxiliary circuits
- G11C11/1673—Reading or sensing circuits or methods
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C7/00—Arrangements for writing information into, or reading information out from, a digital store
- G11C7/06—Sense amplifiers; Associated circuits, e.g. timing or triggering circuits
- G11C7/062—Differential amplifiers of non-latching type, e.g. comparators, long-tailed pairs
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C2207/00—Indexing scheme relating to arrangements for writing information into, or reading information out from, a digital store
- G11C2207/06—Sense amplifier related aspects
- G11C2207/063—Current sense amplifiers
Definitions
- the present invention relates to a magnetic memory device including a memory cell including a magnetoresistive body and capable of recording and reading information.
- This magnetic memory device is a magnetic random access memory (hereinafter also referred to as “MRAM: Magnetic Random Access Memory”!), And includes a plurality of recording cells each including a pair of magnetoresistive elements and a pair of backflow prevention diodes. Are two-dimensionally arranged. In this case, each storage cell stores binary-coded information by increasing the resistance value of one of the pair of magnetoresistive effect elements compared to the other.
- MRAM Magnetic Random Access Memory
- a pair of transistors (column selection) is connected via a Y-direction address decoder shown in FIG.
- the transistor By operating the transistor, the current is supplied to the pair of sense bit lines (current supply lines) via the current-voltage conversion resistors. Make it possible.
- one constant current circuit via the X direction address decoder, it is connected to this constant current circuit and connected to one sense word line (current drawing line)! Makes it possible to draw a constant current.
- one memory cell disposed at the intersection of this pair of current supply lines and this one current drawing line and connected to both lines is selected, and one current-voltage conversion is performed from the power source.
- a current corresponding to the resistance value of each magnetoresistive effect element flows through the second path to the ground via the node and the constant current circuit.
- a voltage proportional to the current value of each current flowing through each path is generated at both ends of each current-voltage conversion resistor disposed in each path.
- each voltage (or voltage difference between each voltage) generated in each current-voltage conversion resistor the magnitude of the resistance value of each magnetoresistive effect element included in the selected memory cell can be determined. It is possible to detect and read the information stored in this recording cell.
- Patent Document 1 Japanese Patent Application Laid-Open No. 2004-178623
- the inventors have found the following points to be improved. That is, in this magnetic memory device, when information stored in each recording cell is read out, the power source is connected to the ground via a current-voltage conversion resistor, a column selection transistor, a magnetoresistance effect element, and a constant current circuit. Current is supplied to each path leading to. However, in order to allow a sufficient current to flow through this path, the magnetoresistive effect element and one of the backflow prevention diodes constituting the memory cell are arranged in series in each path. Requires a high power supply voltage. Therefore, since this magnetic memory device requires a high power supply voltage, there is a problem that power consumption increases and battery driving is difficult.
- the present invention has been made to solve the problem, and has as its main object to provide a magnetic memory device that reads and obtains information even at a lower power supply voltage.
- a magnetic memory device includes a magnetic memory device including a plurality of memory cells arranged in a two-dimensional manner in (1 + 1) rows 0 + 1) columns (1,;
- a memory device wherein each memory cell is provided with one or more magnetoresistive effectors and supplies a first current for sensing a resistance value of the magnetoresistive effecter.
- a first current supply circuit, a second current supply circuit that supplies a second current to the magnetoresistive body, and a total value of the first current and the second current is controlled to be constant Current control circuit to It has.
- each of the memory cells is provided with two magnetoresistive bodies, and each of the magnetoresistive bodies is connected with one current control circuit
- the first current supply circuit includes two sensing resistors that convert the first current into a sensing voltage
- the second current supply circuit sends the second current to each magnetoresistive body.
- Each of the current control circuits controls the total value of the first current flowing through the sensing resistors and the second current flowing through the magnetoresistive body to be constant. To do.
- a differential amplifier circuit that operates based on a voltage difference between the sensing voltages converted by the sensing resistors and reads information stored in the memory cells is provided. ing.
- each of the memory cells is provided with one magnetoresistive body, and the current control circuit is connected to the magnetoresistive body, so that the first current supply is provided.
- the circuit includes a sensing resistor that converts the first current into a sensing voltage, and the second current supply circuit supplies the second current to the magnetoresistive body.
- the differential amplification that operates based on the voltage difference between the sensing voltage converted by the sensing resistor and the reference voltage and stores the information stored in each memory cell. It has a circuit.
- the resistance value of the sensing resistor is defined as a resistance value that is at least twice as large as the resistance value of the magnetoresistive body.
- the first current supply circuit that supplies the first current for sensing the resistance value of the magnetoresistive effect-expressing body, and the second to the magnetoresistive effect-expressing body.
- a second current supply circuit for supplying a constant current and a current control circuit for controlling the sum of the first current and the second current to be constant.
- a current supply circuit and a memory cell can be connected in parallel. For this reason, the first current supply circuit, the memory cell, and the current control circuit are arranged in the memory cell portion as compared with the conventional configuration in which the first voltage supply circuit, the memory cell, and the current control circuit are connected in series between the DC voltage and the ground.
- the voltage required in the series circuit of the first current supply circuit and the current control circuit can be lowered by the amount of voltage drop that occurs. Therefore, even if the DC voltage is lowered to a lower voltage, the first current having a sufficient current value can be supplied, so that low power consumption can be achieved while maintaining a stable reading operation. it can.
- each memory cell is provided with two magnetoresistive effect bodies, and each magnetoresistive effect body is provided with a current control circuit.
- the first current supply circuit has two sensing resistors that convert the first current into a sensing voltage, and the second current supply circuit sends the second current to each magnetoresistive effector.
- Each current control circuit controls each current control circuit by controlling the total value of the first current flowing through each sensing resistor and the second current flowing through each magnetoresistive effect body constant.
- the first current supply circuit and the memory cell (magnetoresistive body) can be connected in parallel.
- the first current supply circuit, the storage cell, and the current control circuit are compared with the conventional configuration in which the DC voltage and the ground are connected in series, and the voltage drop generated in the storage cell portion is the first.
- the voltage required for the series circuit of the current supply circuit 1 and the current control circuit can be lowered. Therefore, even if the DC voltage is lowered to a lower voltage, the first current having a sufficient current value can be supplied, so that low power consumption can be achieved while maintaining a stable reading operation. It is possible to plan.
- the differential amplifier circuit operates based on the voltage difference between the sensing voltages respectively converted by the sensing resistors, and is stored in each memory cell.
- the resistance value of each sensing resistor is set to a resistance value that is larger than the resistance value of each magnetoresistive effect body, thereby increasing the sensitivity when reading information from the recording cell. It can be raised enough.
- each memory cell is provided with one magnetoresistive effect body, and the magnetoresistive effect body is connected with a current control circuit.
- the current supply circuit of 1 includes a sensing resistor that converts the first current into a sensing voltage, and the second current supply circuit supplies the second current to the magnetoresistive effector, thereby providing a current control circuit.
- the first current supply circuit and the memory cell are in parallel. It can be configured to be connected to.
- the voltage drop generated in the memory cell portion is The voltage required in the series circuit of the first current supply circuit and the current control circuit can be lowered. Therefore, even if the DC voltage is lowered to a lower voltage, the first current having a sufficient current value can be supplied, so that low power consumption can be achieved while maintaining a stable reading operation. This comes out.
- the magnetic memory device operates based on the voltage difference between the sensing voltage converted by the sensing resistor and the reference voltage, and is stored in each memory cell.
- the resistance value of the sensing resistor is set to a resistance value that is greater than the resistance value of the magnetoresistive effector, and sensitivity when reading information from the recording cell Can be increased sufficiently.
- the resistance value of the sensing resistor is defined as a resistance value that is at least twice as large as the resistance value of the magnetoresistive body, information from the recording cell is obtained.
- the sensitivity when reading out can be further increased.
- FIG. 1 is a block diagram showing an overall configuration of a magnetic memory device M (Ml).
- FIG. 2 Each read circuit included in memory cell 1 and read circuit group 23 of magnetic memory device M (read circuit 23 ⁇ as an example), and each constant current circuit included in constant current circuit group 25 ( It is a circuit diagram which shows the structure of the constant current circuit 25 (eta) as an example.
- FIG. 3 Memory cell 101 of magnetic memory device Ml, each read circuit included in read circuit group 23 ⁇ (read circuit 23An as an example), and each constant current circuit included in constant current circuit group 25A ( It is a circuit diagram which shows the structure of the constant current circuit 25An) as an example.
- the magnetic memory device M includes an address buffer 11, a data buffer 12, a control logic unit 13, a memory cell group 14, a Y-direction drive control circuit unit 21, and an X-direction drive control circuit unit 31.
- the Y-direction drive control circuit unit 21 has a Y-direction address decoder circuit 22, a readout circuit group 23, a Y-direction current drive circuit group 24, and a constant current circuit group 25.
- the X-direction drive control circuit unit 31 has an X-direction address decoder circuit 32 and an X-direction current drive circuit group 33.
- This magnetic memory device M has data (data buffer 12 via) for memory cell group 14, read circuit group 23, Y direction current drive circuit group 24, constant current circuit group 25, and X direction current drive circuit group 33. Data) to be stored in the predetermined address specified by the address input via the address buffer 11, as many as the number of bits (in this example, 8 as an example) Each bit information (“1” or “0”) constituting the predetermined data is configured to be stored in one memory cell 1 of the predetermined address in the memory cell group 14 corresponding to each bit. ing. Each component included in the magnetic memory device M is operated by a DC voltage Vcc supplied from a DC voltage source between the power supply terminal PW and the ground terminal GND.
- the address buffer 11 includes external address input terminals A0 to A20, and an address signal (for example, an upper address signal among the address signals) taken from the external address input terminals A0 to A20 is transmitted to the Y-direction address bus 15. To the Y-direction address decoder circuit 22 and output an address signal (for example, a lower address signal of the address signals) to the X-direction address decoder circuit 32 via the X-direction address bus 16.
- an address signal for example, an upper address signal among the address signals taken from the external address input terminals A0 to A20 is transmitted to the Y-direction address bus 15.
- an address signal for example, a lower address signal of the address signals
- the data buffer 12 includes external data terminals D0 to D7, an input buffer 12a, and an output buffer 12b.
- the data buffer 12 is connected to the control logic unit 13 via the control signal line 13a.
- the input buffer 12a is connected to each X-direction current drive circuit group 33 via the X-direction write data bus 17, and each Y-direction current drive circuit via the Y-direction write data bus 18.
- the memory cell group corresponding to the information of each bit in the eight memory cell groups 14 is included in the data input via the external data terminals D0 to D7 connected to the group 24. 14 to store each X direction current drive circuit group 33 corresponding to each bit and each Y direction current drive. Output to each circuit group 24.
- the output canister 12b is connected to the read circuit group 23 via the Y-direction read data bus 19.
- the output buffer 12b inputs the data read by the read circuit group 23 via the Y-direction read data bus 19, and outputs the input data to the external data terminals D0 to D7.
- the input buffer 12a and the output buffer 12b operate according to the control signal input from the control logic unit 13 via the control signal line 13a.
- the control logic unit 13 includes an input terminal CS and an input terminal OE, and controls operations of the data buffer 12, the read circuit group 23, the Y-direction current drive circuit group 24, and the X-direction current drive circuit group 33. Specifically, the control logic unit 13 selects either the input buffer 12a or the output buffer 12b based on the chip select signal input via the input terminal CS and the output enable signal input via the input terminal OE. In addition to determining whether or not to activate, a control signal for operating the input buffer 12a and the output buffer 12b is generated in accordance with this determination and output to the data buffer 12 via the control signal line 13a.
- Each memory cell group 14 is composed of a pair of lines arranged in parallel with each other and a plurality ((j + 1) pieces arranged in parallel along the X direction in FIG. 1. j is 1 or more. (Integer) write bit lines (not shown) and multiple ((i + 1) lines arranged in parallel along the Y direction in the figure so as to intersect (orthogonal) each line of the write bit lines.
- I is an integer of 1 or more) write word lines (not shown), and arranged at each intersection of the write bit line and the write word line, so that it is arranged two-dimensionally (as an example ( i + 1) row (j + 1) columns arranged in matrix) (((i + 1) X (j + 1))) memory cells (magnetic memory cells) 1 and juxtaposed
- a plurality of ((j + 1)) read bit lines 5 each composed of a pair of lines 5a and 5b and arranged in parallel with each write bit line, and each write word line Reading multiple ((i + 1)) juxtaposed
- an output word line in this example, word decode lines XO to Xi are also used).
- each storage cell 1 includes a pair of storage elements la and lb.
- Each of the memory elements la and lb includes a magnetoresistive effect body 2a, 2b configured using GMR (Giant Magneto-Reistive) or TMR (Tunneling Magneto-Resistive), and each magnetoresistive effect body 2a, 2 unidirectional each connected in series to 2b Of the magnetoresistive effect body 2a in accordance with the direction of the combined magnetic field generated due to the current supplied to the write bit line and the write word line.
- the state shifts to one of a state where the resistance value is smaller than the resistance value of the magnetoresistive effect body 2b and a state where the resistance value of the magnetoresistance effect body 2a is larger than the resistance value of the magnetoresistance effect body 2b.
- the anodes of the diodes Da and Db are both connected to the word decode line Xm (m is 0 to i).
- the diode Da has its force sword terminal connected to one line 5a of the read bit line 5 through one magnetoresistive body 2a, and the diode Db has its force sword terminal connected to the other magnetoresistive body.
- the read bit line 5 is connected to the other line 5b via 2b.
- Each diode Da, Db only needs to be able to regulate the direction of current (Iwl, Iw2 to be described later) flowing through each magnetoresistive body 2a, 2b from the word decode line Xm to the line 5a, 5b. Therefore, the positions of the magnetoresistive effect body 2a and the diode Da are switched, and the positions of the magnetoresistive effect body 2b and the diode Db are switched so that the magnetoresistive effect bodies 2a and 2b are connected to the word decode line Xm side. It is also possible to adopt a configuration connected to the.
- the Y-direction address decoder circuit 22 of the Y-direction drive control circuit unit 21 includes (j + 1) read signals included in the read circuit group 23 based on the address signal input via the Y-direction address bus 15. Circuit, and Y-direction current drive circuit group 24, and (j + 1) bit decode lines YO, ..., connected to (j + 1) Y-direction current drive circuits, respectively. Select one of Yn, ⁇ , Yj (bit decode line ⁇ , ⁇ is an integer between 0 and j), and apply a predetermined voltage to the selected bit decode line Yn. In this case, the read circuit 23 ⁇ (see FIG.
- the Y-direction current drive circuit connected to the selected bit decode line ⁇ ⁇ among the (j + 1) Y-direction current drive circuits included in the Y-direction current drive circuit group 24 is: It operates when the predetermined voltage is applied via the bit decode line Yn, and supplies a write current to the connected write bit line.
- the X-direction address decoder circuit 32 of the X-direction drive control circuit unit 31 is included in the X-direction current drive circuit group 33 based on an address signal input via the X-direction address bus 16.
- (i + 1) X-direction current drive circuits respectively !, (i + 1)
- One of the word decode lines X0,--, Xm, ..., Xi word decode line Xm. m is an integer between 0 and i, and a predetermined voltage is applied to the selected word decode line Xm.
- the X-direction current drive circuit connected to the selected word decode line Xm among the (i + 1) X-direction current drive circuits included in the X-direction current drive circuit group 33 is It operates when the above-mentioned predetermined voltage is applied via the line Xm, and supplies the write current to the connected write word line.
- (i + 1) word decode lines XO to Xi are included in the 0th to ith rows of each memory cell group 14, respectively, and (j + 1) memory cells 1 are read word lines.
- the (j + 1) memory cells 1 included in the m-th row connected to the selected word decode line Xm are connected to the X-direction address decoder circuit 32 that functions as a DC voltage source.
- a predetermined voltage is applied.
- currents (second currents in the present invention) Iwl and Iw2 corresponding to the resistance values are supplied from the X-direction address decoder circuit 32 to the storage elements la and 1b, respectively.
- Each readout circuit (explained by taking readout circuit 23 ⁇ as an example) is, as shown in FIG. 2, a pre-stage circuit (first current supply circuit in the present invention) 41 and a post-stage circuit (in the present invention).
- the current (first current in the present invention) Ibl and Ib2 is supplied to the lines 5a and 5b, and information is read from the memory cell 1 by detecting the difference between the currents Ibl and Ib2. .
- the pre-stage circuit 41 has two current-voltage conversion resistors Rl, R2 and corresponding resistors Rl, R2 that are connected at one end to the power supply terminal PW.
- Two switch elements for example, NPN type transistors
- Ql and Q2 each having a collector terminal connected to the other end of each and an emitter terminal connected to the corresponding one of the lines 5a and 5b, are connected to each other.
- the current Ibl and Ib2 are supplied to the lines 5a and 5b during operation.
- the resistance values of the resistors Rl and R2 are the same, and the high resistance described later is used.
- the resistance value is set to a sufficiently large resistance value (a resistance value of about 2 times or more.
- the post-stage circuit 42 is configured as a differential amplifier circuit, and the difference value between the currents Ibl and Ib2, specifically, both ends of the resistors Rl and R2 due to the currents Ibl and Ib2. Detects and amplifies the potential difference of the voltage (sensing voltage) generated at the output.
- the pre-stage circuit 41 and the post-stage circuit 42 of the read circuit 23 n are each activated when a predetermined voltage is supplied to the bit decode line Yn selected by the Y-direction address decoder circuit 22 to operate the read circuit 23 ⁇ . Transition to the state.
- a constant current circuit (which is a current control circuit according to the present invention and will be described by taking constant current circuit 25 ⁇ as an example) is connected to each circuit connected to readout circuit 23 ⁇ as shown in FIG.
- the collector terminals are connected to 5a and 5b, and the base current with the same current value (constant value) is always supplied, so that the constant currents Isl and Is2 with the same current value are always drawn.
- a pair of transistors Q3 and Q4 are provided. In this case, the current Isl flowing through the transistor Q3 is read out via the switch element Q1 of the preceding circuit 41 in the read circuit group 23 connected to the selected bit decode line Yn as shown in FIG.
- One line 5a of the read bit line 5 through the current Ibl supplied to one line 5a of the read line 5 and the diode Da and the storage element la of the memory cell 1 connected to the selected word decode line Xm The total current with the current Iwl supplied to.
- the current Is2 flowing through the transistor Q3 is equal to the current Ib2 supplied to the other line 5b of the read bit line 5 via the switch element Q2 of the pre-stage circuit 41, the diode Db of the storage cell 1, and the storage element lb.
- the constant current circuit 25 ⁇ controls the total current value (total value) of the current Ibl and current Iwl to a constant value, and controls the total current value (total value) of the current Ib2 and current Iw2 to a constant value. . Therefore, in each memory cell group 14, the pre-stage circuit 41 of the read circuit 23 ⁇ that supplies the currents Ibl and Ib2 to the lines 5a and 5b of the read bit line 5, and the currents Iwl and Iw2 to the read bit line 5 The memory cell 1 supplied to the lines 5a and 5b is connected in parallel to the constant current circuit 25 ⁇ .
- the memory device M stores information in advance by operating the Y-direction current drive circuit group 24 and the X-direction current drive circuit group 33, respectively.
- the address buffer 11 inputs the address signal input via the external address input terminals ⁇ 0 to ⁇ 20 via the X-direction address bus 16 and the ⁇ -direction address bus 15 to the X-direction address decoder circuit 32 and ⁇ Output to the direction address decoder circuit 22.
- the ⁇ direction address decoder circuit 22 selects one of the bit decode lines YO to Yj (for example, the bit decode line ⁇ ) based on the input address signal.
- the X direction address decoder circuit 32 selects one of the word decode lines ⁇ to Xi (for example, the word decode line Xm) based on the input address signal.
- the output buffer 12b shifts to the operating state and the input buffer 12a shifts to the non-operating state.
- each read circuit 23 ⁇ of each memory cell group 14 selected by the bit decode line Yn a predetermined voltage is applied via the bit decode line ⁇ , whereby the pre-stage circuit 41 and the post-stage circuit Circuit 42 goes into operation.
- the pre-stage circuit 41 is connected to each line of the read bit line 5 connected to the (i + 1) memory cells 1 included in the ⁇ column of the memory cell group 14. Start supplying currents lb 1 and Ib2 to 5a and 5b.
- the (j + 1) memory cells 1 included in the m-th row connected to the selected word decode line Xm in each memory cell group 14 have the word decode line Xm force having a predetermined voltage. Is added.
- each magnetoresistive effect body 2a, 2b included in each memory element la, lb constituting memory cell 1 located in m rows and n columns of each memory cell group 14 is stored in memory cell 1.
- One of them is in a high resistance state and the other is in a low resistance state according to the information of the bit being set.
- the current values of the currents Iwl and Iw2 flowing through the storage elements la and lb are inversely proportional to the resistance values of the magnetoresistive effect manifesting bodies 2a and 2b.
- the current Iwl The current value is smaller than the current value of current Iw2.
- the current value is obtained by subtracting Iwl and Iw2.
- the post-stage circuit 42 of each readout circuit 23 ⁇ has a voltage difference between the voltages generated at both ends of the resistors Rl and R2 based on the currents Ibl and Ib2 (a difference between current values of the currents Ibl and Ib2, that is, By detecting the current value difference between the currents I wl and Iw 2), the information (binary information) stored in the memory cell 1 is acquired and output to the Y-direction read data bus 19.
- the resistance value of each of the resistors Rl and R2 is set to a value more than twice the resistance value of each of the magnetoresistive bodies 2a and 2b when in the high resistance state.
- the difference in the current values of the currents Iwl and Iw2 due to the magnitude of the resistance values of the magnetoresistive effect manifesting bodies 2a and 2b is the voltage difference between the voltages generated at both ends of the resistors Rl and R2. Amplified by 41 and output to the post-stage circuit 42.
- the output buffer 12b outputs the data input via the Y-direction read data bus 19 to the external data terminals D0 to D7. Thus, reading of data stored in the memory cell 1 is completed.
- the two magnetoresistive bodies 2a and 2b are arranged in each memory cell 1, and each of the read circuits included in the read circuit group 23 is provided.
- the pre-stage circuit 41 supplies currents Ibl and Ib2 for sensing the resistance values of the magnetoresistive effect bodies 2a and 2b included in the memory cell 1, and the X-direction address decoder circuit 32
- the currents Iwl and Iw2 are supplied to the gas resistance effect developing body 2a and 2b, and the constant current circuit of the constant current circuit group 25 is the sum of the current Ibl and the current Iwl (current value of the current Isl) and the current Ib2 and the current Iw2.
- the pre-stage circuit 41 and the memory cell 1 are connected in parallel to each constant current circuit included in the constant current circuit group 25. Can be configured. For this reason, compared with the conventional configuration in which the readout circuit, memory cell, and constant current circuit are connected in series between the DC voltage Vcc and the ground, the preceding stage circuit is equivalent to the voltage drop that occurs in the memory cell 1 part. The voltage required for the series circuit of 41 and the constant current circuit can be lowered.
- the currents Ibl and Ib2 having sufficient current values can be supplied to the lines 5a and 5b of the read bit line 5, so that a stable read operation can be performed. Low while maintaining Power consumption can be reduced.
- the post-stage circuit 42 operates based on the voltage difference between the sensing voltages converted by the resistors Rl and R2, respectively, and reads out the information stored in each memory cell 1.
- the resistance values of the resistors Rl and R2 are larger than the resistance values of the magnetoresistive bodies 2a and 2b, the sensitivity when reading information from the recording cell 1 can be sufficiently increased.
- the resistance values of the resistors Rl and R2 are at least twice as large as the resistance values of the magnetoresistive elements 2a and 2b, the sensitivity when reading information from the recording cell 1 is further increased. be able to.
- the present invention is not limited to the above-described configuration.
- the force recording cell described in the example in which the recording cell 1 is configured by a pair of storage elements la and lb can be configured by one storage element.
- This magnetic memory device can be realized by using one circuit of the same configuration in a circuit in which two systems of the same configuration are arranged based on the configuration of the magnetic memory device M described above.
- a magnetic memory device Ml in which a recording cell is constituted by one storage element will be described. Note that the same configuration as that of the magnetic memory device M is denoted by the same reference numeral, and redundant description is omitted.
- the magnetic memory device Ml includes an address buffer 11, a data buffer 12, a control logic unit 13, a memory cell group 14A, a Y-direction drive control circuit unit 21A, and an X-direction drive control circuit unit 31. It has.
- the Y-direction drive control circuit unit 21A has a Y-direction address decoder circuit 22, a read circuit group 23A, a Y-direction current drive circuit group 24A, and a constant current circuit group 25A.
- the X direction drive control circuit unit 31 includes an X direction address decoder circuit 32 and an X direction current drive circuit group 33.
- this magnetic memory device Ml has the same number of bits as the memory cell group 14A, the read circuit group 23A, the Y-direction current drive circuit group 24A, the constant current circuit group 25A, and An X-direction current drive circuit group 33 is provided.
- the read bit line 5 is composed of one line 5a.
- Each storage cell 101 is configured to include one storage element la as shown in FIG.
- the memory element la is composed of one magnetoresistive element 2a and one unidirectional element (for example, a diode Da), and the resistance value of the magnetoresistive element 2a. By shifting to either the high resistance state or the low resistance state, the information of each bit constituting the data is stored.
- a predetermined voltage (reference voltage) VI is supplied to the base terminal of the transistor connected to the collector terminal of the switch element Q 2 of the pre-stage circuit 41.
- Each constant current circuit included in the constant current circuit group 25A (which will be described below using the constant current circuit 25An connected to the memory cell 101 in the nth column as an example) is a line of the read bit line 5. Since 5b does not exist, as shown in the figure, the resistor connected to the transistor Q4 and its emitter terminal is omitted, and only the circuit including the transistor Q3 is configured.
- the post-stage circuit 42 has a voltage between the sensing voltage converted by the resistor R1 and the voltage VI.
- the resistance value of the resistor R1 is regulated to be larger than the resistance value of the magnetoresistive effect-producing body 2a. Sensitivity when reading information from 101 can be sufficiently increased.
- information is read from the recording cell 101 by defining the resistance value of the resistor R1 to be a resistance value that is twice or more larger than the resistance value of the magnetoresistive body 2a. Sensitivity can be further increased.
- each readout circuit and each constant current circuit described above are configured using transistors, they can be configured using FETs (field effect transistors) instead of transistors.
- the first current supply circuit that supplies the first current for sensing the resistance value of the magnetoresistive body and the magnetoresistive effect
- the current control circuit includes a second current supply circuit that supplies a second current to the developing body and a current control circuit that controls the total value of the first current and the second current to be constant.
- the first current supply circuit and the memory cell can be connected in parallel. For this reason, the first current supply circuit, the memory cell, and the current control circuit are compared with the conventional configuration in which the first voltage supply circuit, the memory cell, and the current control circuit are connected in series between the DC voltage and the ground.
- the voltage required in the series circuit of the current supply circuit 1 and the current control circuit can be lowered. Therefore, even if the direct current voltage is lowered to a lower voltage, the first current having a sufficient current value can be supplied. As a result, a magnetic memory device capable of reducing power consumption while maintaining a stable reading operation is realized.
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- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Mram Or Spin Memory Techniques (AREA)
- Semiconductor Memories (AREA)
- Hall/Mr Elements (AREA)
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US11/721,141 US7808813B2 (en) | 2004-12-08 | 2005-12-07 | Magnetic memory cell reading apparatus |
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JP2004-355507 | 2004-12-08 | ||
JP2004355507A JP4517842B2 (ja) | 2004-12-08 | 2004-12-08 | 磁気メモリデバイス |
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Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH01149291A (ja) * | 1987-12-04 | 1989-06-12 | Nec Corp | 半導体記憶装置 |
JP2004280910A (ja) * | 2003-03-13 | 2004-10-07 | Tdk Corp | 磁気メモリデバイスおよびその読出方法 |
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JP3031298B2 (ja) * | 1997-06-18 | 2000-04-10 | 日本電気株式会社 | 電流検出型センスアンプ |
JP4046513B2 (ja) * | 2002-01-30 | 2008-02-13 | 株式会社ルネサステクノロジ | 半導体集積回路 |
KR100515053B1 (ko) * | 2002-10-02 | 2005-09-14 | 삼성전자주식회사 | 비트라인 클램핑 전압 레벨에 대해 안정적인 독출 동작이가능한 마그네틱 메모리 장치 |
JP4365576B2 (ja) | 2002-11-22 | 2009-11-18 | Tdk株式会社 | 磁気メモリデバイスおよび書込電流駆動回路、並びに書込電流駆動方法 |
US6775195B1 (en) * | 2003-02-28 | 2004-08-10 | Union Semiconductor Technology Center | Apparatus and method for accessing a magnetoresistive random access memory array |
JP4419408B2 (ja) * | 2003-03-14 | 2010-02-24 | Tdk株式会社 | 磁気抵抗効果素子および磁気メモリデバイス |
JP4492052B2 (ja) * | 2003-08-21 | 2010-06-30 | Tdk株式会社 | 磁気記憶セルおよび磁気メモリデバイス |
JP2006294155A (ja) * | 2005-04-13 | 2006-10-26 | Tdk Corp | 磁気メモリデバイス |
JP4779487B2 (ja) * | 2005-07-25 | 2011-09-28 | Tdk株式会社 | 磁気メモリデバイス |
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Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH01149291A (ja) * | 1987-12-04 | 1989-06-12 | Nec Corp | 半導体記憶装置 |
JP2004280910A (ja) * | 2003-03-13 | 2004-10-07 | Tdk Corp | 磁気メモリデバイスおよびその読出方法 |
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US20090290405A1 (en) | 2009-11-26 |
US7808813B2 (en) | 2010-10-05 |
JP4517842B2 (ja) | 2010-08-04 |
JP2006164421A (ja) | 2006-06-22 |
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