US20010043489A1 - Nonvolatile memory sensing circuit and techniques thereof - Google Patents
Nonvolatile memory sensing circuit and techniques thereof Download PDFInfo
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- US20010043489A1 US20010043489A1 US09/901,898 US90189801A US2001043489A1 US 20010043489 A1 US20010043489 A1 US 20010043489A1 US 90189801 A US90189801 A US 90189801A US 2001043489 A1 US2001043489 A1 US 2001043489A1
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C16/00—Erasable programmable read-only memories
- G11C16/02—Erasable programmable read-only memories electrically programmable
- G11C16/06—Auxiliary circuits, e.g. for writing into memory
- G11C16/26—Sensing or reading circuits; Data output circuits
- G11C16/28—Sensing or reading circuits; Data output circuits using differential sensing or reference cells, e.g. dummy cells
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C16/00—Erasable programmable read-only memories
- G11C16/02—Erasable programmable read-only memories electrically programmable
- G11C16/06—Auxiliary circuits, e.g. for writing into memory
-
- 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
- G11C11/56—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
- G11C11/5621—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency using charge storage in a floating gate
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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
- G11C11/56—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
- G11C11/5621—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency using charge storage in a floating gate
- G11C11/5642—Sensing or reading circuits; Data output circuits
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C2211/00—Indexing scheme relating to digital stores characterized by the use of particular electric or magnetic storage elements; Storage elements therefor
- G11C2211/56—Indexing scheme relating to G11C11/56 and sub-groups for features not covered by these groups
- G11C2211/563—Multilevel memory reading aspects
- G11C2211/5634—Reference cells
Definitions
- the present invention relates to semiconductor memory, more particularly, to nonvolatile memory sensing circuits and techniques thereof which improve the reference structure therein.
- FIG. 1 shows a nonvolatile memory sensing circuit of two levels according to a related art
- FIG. 2 shows a nonvolatile memory sensing circuit of multi-levels according to a related art.
- a main cell array 110 including a main cell MC receives word line signals WL and selectively decodes the main cell.
- a voltage clamp 130 rapidly charges a bit line of the main cell MC and maintains fixed voltage therein.
- the voltage clamp 130 includes two transistors NM 2 and NM 3 of which drains are connected to applied voltage VCC and a sense amplifier 150 respectively, and an inverter INV 1 which is connected commonly between sources and gates of the transistors NM 2 and NM 3 .
- the inverter INV 1 and NMOS transistor NM 2 of which drain is connected to applied voltage VCC form a negative feed-back to the other NMOS transistor NM 3 connecting the main cell to the sense amplifier 150 , controlling drain voltage of another NMOS transistor NM 1 .
- a reference cell controller 120 supplies a gate of a reference cell RFC with drain voltage Vd, control gate voltage Vcg, and erasing gate voltage Veg or erases them. Namely, outputs of an erasing decoder 125 and a program decoder 123 are outputted to a reference cell RFC through a cell erasing or program selection circuit 121 .
- a reference cell array 140 having the reference cell RFC provides the sense amplifier 150 with the criteria judging the data stored in the main cell MC through an NMOS transistor NM 4 of which gate receives clock signals.
- the sense amplifier 150 which includes an NMOS transistor, PMOS transistors PM 1 and PM 2 , and a latch part 151 produces the result SA by comparing the levels of the reference cell RFC and main cell MC.
- Applied voltage VCC is applied to sources of the PMOS transistors PM 1 and PM 2 having a common gate.
- a drain and gate of the PMOS transistor PM 1 are connected to the reference cell RFC in common while a drain of the other PMOS transistor PM 2 is connected to the main cell MC and a stage of an NMOS transistor NM 5 of which gate receives a clock signal.
- the latch part 151 connected to the other stage of the NMOS transistor NM 5 outputs the result therefrom.
- the latch part 151 includes a pair of inverters INV 2 and INV 3 which form a feed-back structure.
- the sense amplifier 150 when the main cell MC is on the stage of reading operation, transforms the information of the reference cell RFC into reference voltage with the PMOS transistor PM 1 , then supplies the gate of the PMOS transistor PM 2 with the reference voltage as gate voltage. Then, drain voltage of the PMOS transistor PM 2 is transmitted to the latch part 151 through the NMOS transistor NM 5 when the clock signal is at “high”.
- the cell controller 120 is in charge of the programming/erasing of the reference cell RFC in use of drain voltage Vd, control gate voltage Vcg, or erasing gate voltage Veg in accordance with each operational state.
- the NMOS transistor NM 4 is turned on.
- drain voltage of the PMOS transistor PM 1 becomes reference voltage of the reference cell RFC since charges are transferred from applied voltage Vcc to the reference cell RFC.
- the same charges of the reference voltage applied to the gates of the PMOS transistors PM 1 and PM 2 of the sense amplifier 150 is also flown to the main cell MC because of the mirror phenomenon.
- the clock signal CLK is enabled and a read signal READ is applied.
- the NMOS transistor NM 1 is turned on by receiving the word line signal WL to generate charge level of the main cell MC through the voltage clamp 130 to the sense amplifier 150 .
- the voltage applied to a source of the NMOS transistor NM 5 is recognized as ‘high level’.
- the voltage applied to the source of the NMOS transistor NM 5 is recognized as ‘low level’.
- a drain voltage of the NMOS transistor NM 1 is kept at fixed level by means of the fixed voltage clamp 130 . Therefore, there is less chance that the main cell MC is exposed to bit line voltage and the sensitivity of the sense amplifier is increased to prevent the sensing operation being affected by the current variation of the main cell MC when the bit line is influenced by external factors on sensing.
- the result SA of the voltage level applied to the source of the NMOS transistor NM 5 is outputted by the latch part 151 .
- FIG. 2 shows a nonvolatile memory sensing circuit of multi-levels according to a related art.
- a main cell array 210 including a main cell MC receives word line signals WL and selectively decodes the main cell.
- a voltage clamp 230 rapidly charges a bit line of the main cell MC and maintains fixed voltage.
- a reference cell controller 220 supplies a reference cell array 240 with drain voltage Vd, control gate voltage Vcg, and erasing gate voltage Veg.
- a cell erasing and program selection circuit 221 receiving an erasing signal Erase and programming signal Program which are decoded by an erasing decoder 225 and programming decoder 223 , which decode the erasing gate voltage Veg in accordance with the erasing or programming operation, supplies a reference cell array 240 with voltage of erasing or programming level.
- Various levels of a plurality of reference cells Ref Cell 1 to Ref Cell k in the reference cell array 240 are applied to a sense amplifier 250 by the NMOS transistors N 11 to N 1 k of which gates receive a plurality of clock signals CLK 1 to CLKk, respectively.
- the sense amplifier 250 which includes PMOS transistors P 1 and P 2 , a plurality of NMOS transistors N 21 to N 2 k, and a plurality of latch parts, outputs the results SA 1 to SAk by comparing the multi level of the reference cell array 250 to the level of the main cell MC.
- Applied voltage VCC is connected to sources of the PMOS transistors P 1 and P 2 which share a gate in common.
- a drain of the PMOS transistor P 1 and the common gate are connected to a reference cell.
- a drain of the other PMOS transistor is connected to the main cell as well as a plurality of the NMOS transistors N 21 to N 2 k of which gates receive a plurality of clock signals CLK 1 to CLKk in parallel.
- Each of the latch parts includes a pair of inverters forming a feed-back structure.
- the decoder 260 outputs the final values Bit 1 to BitL by decoding the results SA 1 to SAk produced by the sense amplifier 250 .
- the nonvolatile memory sensing circuit of multi-levels shows the same operation as that of the circuit of two levels, except for having the reference cell array 240 consist of a plurality of reference cells Ref Cell 1 to Ref Cellk and programming various k number of reference voltages to sense the multi-levels of k+1.
- the sense amplifier 250 supplied with charge levels of a plurality of the reference cells Ref Cell 1 to Ref Cellk and the main cell MC stores the results in a plurality of the latch parts 151 by comparing the multi-levels of the reference cell array 240 to the level of the main cell MC.
- the results SA 1 to SAk are produced to the decoder 260 .
- the decoder 260 outputs the final values Bit 1 to BitL by judging the data of the main cell MC by decoding the results SA 1 to SAk outputted by the sense amplifier 250 .
- both of the memory sensing circuits of two and multi-levels require an additional controller such as program control means and read control means for the main and reference cell programs and for reading the main or reference cell.
- program control means and read control means for the main and reference cell programs and for reading the main or reference cell.
- the sensing margin is decreased by the influence on the reference cell due to the voltage offset of the reading control means when the reference cell is read by the reading control means, thereby causing the direct fail in the precise reading operation of the memory sensing circuit of multi-levels of which reading margin is basically less than that of two levels.
- the present invention is directed to nonvolatile memory sensing circuits and techniques thereof that substantially obviate one or more problems due to limitations and disadvantages of the related art.
- An object of the present invention is to provide nonvolatile memory sensing circuits and techniques thereof which improve the reference structure for securing the sensing margin on reading by canceling out the voltage offset reflected on the main or reference cell.
- the present invention of a nonvolatile memory sensing circuit including a main cell part and at least one reference cell part, comprises a main cell array having a plurality of main cells to which word line driving signal is applied respectively, a plurality of main cell switches receiving a plurality of main cell selection signals YG 0 to YGn which switch to select one of the main cells, respectively, wherein the main cell switches are connected to the main cell array in series, a main cell bit line voltage controller maintaining drain voltage at a fixed level by receiving program bias voltage PRBIAS, a main cell path transistor connected between an output of the main cell bit line voltage controller and internal power supply voltage, wherein the main cell path transistor outputs a state of the main cell, and at least one sense amplifier producing a comparison output SAOUT by receiving at least one reference voltage RDREF and an output SENSE of the main cell path transistor, wherein the reference cell part further comprises program reference cell part and read reference
- the present invention includes a method of operating a nonvolatile memory sensing circuit comprising the steps of driving a memory sensing means by applying internal power supply voltage VPD and external power supply voltage VDD, programming a program reference cell PFC, generating program reference cell bias voltage PGMBIAS for programming a read reference cell RFC, programming the read reference cell RFC, generating reference voltage RDREF for programming a main cell MC, programming the main cell MC by using the reference voltage RDREF, and reading data stored in the main cell MC, wherein drain or source voltage of the program reference cell and read reference cell is maintained at a predetermined level by a common means when programming or reading is carried out.
- FIG. 1 shows a nonvolatile memory sensing circuit of two levels according to a related art
- FIG. 2 shows a nonvolatile memory sensing circuit of multi-levels according to a related art
- FIG. 3 shows a nonvolatile memory sensing circuit of two levels according to the present invention
- FIG. 4 shows a nonvolatile memory sensing circuit of multi-levels according to the present invention
- FIG. 5 shows a nonvolatile memory sensing circuit of two levels according to another embodiment of the present invention.
- FIG. 6 shows a flow chart of operation of the nonvolatile sensing memory circuit of two levels according to another embodiment of the present invention
- FIG. 7 shows a specific flow chart of the steps of programming a program reference cell in FIG. 6.
- FIG. 8 shows a specific flow chart of the steps of generating program reference cell bias voltage in FIG. 6;
- FIG. 9 shows a specific flow chart of the steps of programming a read reference cell in FIG. 6;
- FIG. 10 shows a specific flow chart of the steps of generating reference voltage for a main cell programming in FIG. 6;
- FIG. 11 shows a specific flow chart of the steps of programming the main cell in FIG. 6.
- FIG. 12 shows a specific flow chart of the steps of reading the main cell in FIG. 6.
- FIG. 3 shows a nonvolatile memory sensing circuit of two levels according to the present invention.
- the nonvolatile memory sensing circuit of two levels according to the present invention is comprised of a main cell part 1500 and a reference cell part 1000 .
- the reference cell part 1000 consists of a program reference cell part 800 and read reference cell part 900 which connected to a common means for controlling drain and source voltage to predetermined level on programming or reading.
- the main cell part 1500 is comprised of a main cell array 1550 including a plurality of main cells MC receiving word line driving signals respectively, a plurality of main cell switches NM 100 to NM 10 n receiving a plurality of main cell selection signals YG 0 to YGn, respectively, which selects one of the main cells MC and connected to the main cell array 1550 , a main cell bit line voltage controller 1555 maintaining drain voltage of the main cell MC by receiving program bias voltage PRBIAS, a main cell path transistor MP 101 which is connected between the main cell bit line controller 1555 and internal power supply voltage VPD and which outputs the state of the main cell, and a sense amplifier 1566 which receives an output SENSE and reference voltage RDREF of the main cell path transistor and generates an output by comparing the SENSE and the RDREF.
- a main cell array 1550 including a plurality of main cells MC receiving word line driving signals respectively, a plurality of main cell switches NM 100 to NM 10 n receiving a plurality of
- a program reference cell part 800 includes at least one program reference cell PFC receiving a program reference word line driving signal PWL, a program cell voltage controller 1111 adjusting drain voltage of the program reference cells to the level under external power supply voltage VDD by receiving read bias voltage RDBIAS, a plurality of program cell switches NM 120 to NM 12 n which are connected to an output of the program cell voltage controller 1111 in series and which receive a plurality of program cell gate selection signals PYG 0 to PYGn selecting one of the program reference cells PFC, a program cell bit line voltage controller 850 maintaining proper drain voltage when the program reference cell is programmed or read by receiving the program bias voltage PRBIAS, a program reference cell path transistor MP 103 which is connected between an output of the program cell bit line voltage controller 850 and internal power supply voltage VPD and generates program reference cell bias voltage PGMBIAS, and a first comparator 870 outputting a program end signal PFPMEND by comparing the program reference cell bias voltage PGMBIAS to the program reference voltage PGMREF
- the read reference cell part 900 is comprised of at least one read reference cell RFC receiving a read word line driving signal RWL, a plurality of read reference cell switches NM 110 to NM 11 n which receive an output of the program cell voltage controller 1111 of the program reference cell part 800 as well as a plurality of read cell gate selection signals RYG 0 to RYGn selecting one of the read reference cells RFC and which are connected to the read reference cell RFC in series, a read cell bit line voltage controller 950 maintaining drain voltage at proper fixed level when the read reference cell is programmed or read by receiving program bias voltage PRBIAS, a read reference cell path transistor MP 102 which is connected between the read cell bit line voltage controller 950 and internal power supply voltage VPD and generates reference voltage RDREF, and a second comparator 970 outputting a read program end signal RFPMEND by comparing reference voltage RDREF to the output PGMBIAS of the program reference cell path transistor.
- the main cell bit line voltage controller 1555 is comprised of a first OP amplifier OPA 1 outputting a main cell voltage regulating signal reg 1 wherein program bias voltage PRBIAS is inputted to a positive terminal and drain voltage applied through a plurality of main cell switches NM 100 to NM 10 n is inputted to a negative terminal, and an NMOS transistor NM 1 of which gate is supplied with the main cell voltage regulating signal reg 1 wherein a drain is connected to the main cell switches and a source is connected to the main cell path transistor MP 101 .
- the sense amplifier 1566 consists of a second OP amplifier OPA 2 outputting a result SAOUT by receiving internal power supply voltage VPD wherein an output SENSE of the main cell path transistor is inputted to a negative terminal and reference voltage RDREF is inputted to a positive terminal.
- the program cell bit line voltage controller 850 is comprised of a fifth OP amplifier OPA 5 outputting a program cell voltage regulating signal reg 3 by receiving internal power supply voltage wherein program bias voltage PRBIAS is inputted to a positive terminal and drain voltage of the program reference cell applied by a plurality of program cell switches NM 120 to NM 12 n is inputted to a negative terminal and an NMOS transistor NM 3 wherein a drain is connected to the NMOS switches, a source is connected to the program reference cell path transistor MP 103 , and the gate is supplied with the program cell voltage regulating signal reg 3 .
- the read cell bit line voltage controller 950 is comprised of a third OP amplifier OPA 3 outputting the read voltage regulating signal reg 2 by receiving internal power supply voltage VPD wherein program bias voltage PRBIAS is inputted to a positive terminal and a drain voltage of the read reference cell RFC applied through a plurality of read reference cell switches NM 110 to NM 1 n is inputted to a negative terminal and an NMOS transistor NM 2 wherein a drain is connected to the read reference cell switches NM 1 10 to NM 1 in, a source is connected to the read reference cell path transistor MP 102 , and a gate is supplied with the program cell voltage regulating signal reg 2 .
- the first comparator 870 consists of a sixth OP amplifier OPA 6 outputting the program end signal PFPMEND by receiving internal power supply voltage VPD wherein the program reference cell bias voltage PGMBIAS is inputted to a negative terminal and the program reference voltage PGMREF is inputted to a positive terminal.
- the second comparator 970 consists of a fourth OP amplifier OPA 4 outputting the read program end signal RFPMEND by receiving internal power supply voltage VPD wherein the program reference cell bias voltage PGMBIAS is inputted to a positive terminal and the reference voltage RDREF is inputted to a negative terminal.
- the program cell voltage controller 1111 is comprised of an OP amplifier outputting a voltage regulating signal reg 4 by receiving external power supply voltage VDD wherein drain voltage of the program reference cell PFC is inputted to a negative terminal and read bias voltage RDBIAS is inputted to a positive terminal and an NMOS transistor NM 4 of which source and drain are shared by those of the program cell switches NM 120 to NM 12 n respectively wherein a voltage regulating signal reg 4 is inputted to a gate of the transistor NM 4 .
- the main cell path transistor MP 101 , program reference cell path transistor MP 103 , and read reference cell path transistor MP 102 , of which sources are supplied with internal power supply voltage VPD, consist of PMOS transistors of which sources are supplied with internal power supply voltage VPD and which have common gates and drains.
- FIG. 4 shows a nonvolatile memory sensing circuit of multi-levels according to the present invention.
- the nonvolatile memory sensing circuit of multi-levels of the present invention is comprised of a multi main cell part 2000 and a multi reference cell part 3000 .
- the multi reference cell part 3000 includes a plurality of reference cell parts 1000 which produce different reference voltage RDREF 1 to RDREFn, respectively.
- the multi main cell part 2000 includes a plurality of multi main cell switches NM 200 to NM 20 n which are connected in series to a plurality of main cells MC receiving a word line driving signal WL, respectively, and are supplied with a plurality of main cell selection signals YG 0 to YGn, a multi main cell bit line voltage controller 2111 maintaining drain voltage of the main cell to fixed level by receiving program bias voltage PRBIAS, a main cell path transistor MP 201 which is connected between an output of the multi main cell bit line voltage controller 2111 and internal power supply voltage VPD and generate a state of the main cell, and a plurality of sense amplifiers 2333 , 3444 , and 2555 producing comparison outputs by receiving an output SENSE of the main cell path transistor and a plurality of the reference voltage RDREF 1 to RDREFn, respectively.
- FIG. 5 shows a nonvolatile memory sensing circuit of two levels according to another embodiment of the present invention.
- the nonvolatile memory sensing circuit of two levels of the present invention is comprised of a main cell part 4500 and a reference cell part 4000 .
- the reference cell part 4000 is comprised of a program reference cell part 3800 and read reference cell part 3900 which shares a control means regulating drain or source voltage of a cell on programming or reading.
- the main cell part 4500 includes a main cell array 4550 including a plurality of main cells MC receiving a word line driving signal WL, respectively, a plurality of main cell switches NM 400 to NM 40 n which are connected in series to the main cell array 4550 and are supplied with a plurality of main cell selection signals YGO to YGn selecting one of the main cells, a main cell bit line voltage controller 4555 maintaining drain voltage of the main cell to fixed level by receiving program bias voltage PRBIAS, a main cell path transistor MP 301 which is connected between an output of the main cell bit line voltage controller 4555 and internal power supply voltage VPD and generate a state of the main cell, and a sense amplifier 4566 producing comparison outputs by receiving an output SENSE of the main cell path transistor and reference voltage RDREF.
- a main cell array 4550 including a plurality of main cells MC receiving a word line driving signal WL, respectively, a plurality of main cell switches NM 400 to NM 40 n which are connected in series to the main cell array 45
- the program reference cell part 3800 includes at least one program reference cell PFC receiving a program reference word line driving signal PWL, a program cell voltage controller 2222 adjusting drain voltage of the program reference cells PFC to the level under external power supply voltage VDD by receiving read bias voltage RDBIAS, a plurality of program cell switches NM 440 to NM 44 n which are connected in series to an output of the program cell voltage controller 2222 and which receive a plurality of program cell gate selection signals PYG 0 to PYGn selecting one of the program reference cells PFC, a program cell bit line voltage controller 3850 maintaining proper level of drain voltage when the program reference cell is programmed or read by receiving the program bias voltage PRBIAS, a program reference cell path transistor which is connected between an output of the program cell bit line voltage controller 3850 and internal power supply voltage VPD and generates program reference cell bias voltage PGMBIAS, and a first comparator 3870 outputting a program end signal PFPMEND by comparing the program reference cell bias voltage PGMBIAS to the program reference voltage
- the read reference cell part 3900 is comprised of at least one read reference cell RFC receiving a read word line driving signal RWL, a plurality of read reference cell switches NM 420 to NM 42 n which receive an output of the program cell voltage controller 2222 of the program reference cell part 3800 as well as a plurality of read cell gate selection signals RYG 0 to RYGn selecting one of the read reference cells RFC and which are connected to the read reference cell RFC in series, a read cell bit line voltage controller 3950 maintaining drain voltage to proper fixed level when the read reference cell is programmed or read by receiving program bias voltage PRBIAS, a read reference cell path transistor which is connected between the read cell bit line voltage controller 3950 and internal power supply voltage VPD and generates reference voltage RDREF, and a second comparator 3970 outputting a read program end signal RFPMEND by comparing reference voltage RDREF to the output PGMBIAS of the program reference cell path transistor.
- the main cell bit line voltage controller 4555 is comprised of an 101th OP amplifier OPA 101 outputting a main cell voltage regulating signal reg 1 wherein program bias voltage PRBIAS is inputted to a positive terminal and drain voltage applied through a plurality of main cell switches NM 400 to NM 40 n is inputted to a negative terminal and a PMOS transistor PM 311 of which gate is supplied with the main cell voltage regulating signal reg 1 wherein a drain is connected to the main cell switches and a source is connected to the main cell path transistor.
- the sense amplifier 4566 consists of an 102th OP amplifier OPA 102 outputting a result SAOUT by receiving internal power supply voltage VPD wherein an output SENSE of the main cell path transistor is inputted to a negative terminal and reference voltage RDREF is inputted to a positive terminal.
- the program cell bit line voltage controller 3850 is comprised of an 105th OP amplifier OPA 105 outputting a program cell voltage regulating signal reg 3 by receiving internal power supply voltage wherein program bias voltage PRBIAS is inputted to a positive terminal and drain voltage of the program reference cell applied by a plurality of program cell switches NM 440 to NM 44 n is inputted to a negative terminal and a PMOS transistor PM 313 wherein a drain is connected to the drain of the program cell switch NM 440 , a source is connected to the program reference cell path transistor, and the gate is supplied with the program cell voltage regulating signal reg 3 .
- the read cell bit line voltage controller 3950 is comprised of an 103th OP amplifier OPA 103 outputting a read voltage regulating signal reg 2 by receiving internal power supply voltage VPD wherein program bias voltage PRBIAS is inputted to a positive terminal and a drain voltage of the read reference cell RFC applied through a plurality of read reference cell switches NM 420 to NM 42 n is inputted to a negative terminal and a PMOS transistor PM 312 wherein a drain is connected to the read reference cell switches NM 420 to NM 42 n, a source is connected to the read reference cell path transistor, and a gate is supplied with the program cell voltage regulating signal reg 2 .
- the first comparator 3870 consists of an 106th OP amplifier OPA 106 outputting the program end signal PFPMEND by receiving internal power supply voltage VPD wherein the program reference cell bias voltage PGMBIAS is inputted to a negative terminal and the program reference voltage PGMREF is inputted to a positive terminal.
- the second comparator 3970 consists of an 104th OP amplifier OPA 104 outputting the read program end signal RFPMEND by receiving internal power supply voltage VPD wherein the program reference cell bias voltage PGMBIAS is inputted to a positive terminal and the reference voltage RDREF is inputted to a negative terminal.
- the program cell voltage controller 2222 is comprised of an 107th OP amplifier OPA 107 outputting a voltage regulating signal reg 4 by receiving external power supply voltage VDD wherein drain voltage of the program reference cell PFC is inputted to a negative terminal and read bias voltage RDBIAS is inputted to a positive terminal and an NMOS transistor NM 300 of which source and drain are shared by those of the program cell switches NM 440 to NM 44 n respectively wherein the voltage regulating signal reg 4 is inputted to a gate of the transistor NM 300 .
- the main cell path transistor, program reference cell path transistor, and read reference cell path transistor, of which sources are supplied with internal power supply voltage VPD, consist of PMOS transistors of which sources are supplied with internal power supply voltage VPD and which have common gates and drains.
- FIG. 6 shows a flow chart of operation of the nonvolatile sensing memory circuit of two levels according to the present invention.
- the steps of the operation of the nonvolatile memory sensing circuit according to the present invention are as follows:
- step 1 a memory sensing circuit is driven by applying internal and external power supply voltages VPD and VDD;
- step 2 a program reference cell PFC is programmed
- step 3 program reference cell bias voltage PGMBIAS is produced to program a read reference cell RFC;
- step 4 the read reference cell RFC is programmed
- step 5 reference voltage RDREF is produced to program a main cell
- step 6 the main cell is programmed by using the reference voltage RDREF.
- step 7 data stored in the main cell is read.
- FIG. 7 shows a specific flow chart of the steps of programming the program reference cell in FIG. 6. The step 2 in FIG. 6 is explained in detail as follows:
- step 2 a internal power supply voltage VPD of which a level is higher than a level of external power supply voltage VDD is applied.
- the first comparator 870 is supplied with program reference voltage PGMREF, and program bias voltage of 6V is applied to a positive terminal of the program cell bit line voltage controller 850 of the program reference cell PFC;
- step 2 b the fifth and sixth OP amplifiers are driven by the applied signal, while the seventh OP amplifier is not driven;
- step 2 c a plurality of program cell gate selection signals PYG 0 to PYG(n ⁇ 1) which are selectively applied for the bit line path of at least one program reference cell PFC turns on a plurality of the program cell switches NM 120 to NM 12 (n ⁇ 1) by selective switching.
- the program cell gate selection signal PYGn of high level is applied to turn on the program cell switch NM 12 n and the drain of the program reference cell PFC is supplied with 6V;
- step 2 d the program reference cell PFC is programmed as the program reference word line driving signal PWL is applied;
- step 2 e as a level of the program reference cell bias voltage PGMBIAS applied to the first comparator 870 becomes higher in the process of the programming the program reference cell PFC, the program end signal PFPMEND of high level is outputted;
- step 2 f turning off the NMOS transistor NM 3 to cut off internal supply voltage VPD and eliminating charges that have been supplied to the bit line to stop diving the fifth OP amplifier with the program end signal PFPMEND to terminate the programming of the program reference cell PFC and to prevent from being programmed over-level which is unwanted by the program reference cell PFC.
- FIG. 8 shows a specific flow chart of the steps of generating program reference cell bias voltage in FIG. 6.
- the step 3 of generating program reference cell bias voltage PGMBIAS to program a read reference cell RFC further includes the steps of:
- step 3 a internal power supply voltage VPD of which level is higher than that of external power supply voltage VDD is applied.
- the program bias voltage of 6V is applied to the program cell bit line voltage controller 850 of the program reference cell PFC, and read bias voltage of 1.25V is applied to the program cell voltage controller 1111 ;
- step 3 b the fifth and seventh OP amplifiers are driven by the applied signal, while the sixth amplifier is not driven;
- step 3 c a plurality of program cell switches NM 120 to NM 12 (n ⁇ 1) are turned on selectively by supplying a plurality of program cell gate selection signals PYG 0 to PYG(n ⁇ 1), which select the bit line path of the program reference cell PFC, of high level for selective switching.
- the program cell switch NM 12 n is turned off by supplying a program cell gate selection signal PYGn of low level;
- step 3 d when the program reference word line driving signal PWL is applied, the program reference cell PFC which is not programmed outputs fixed DC current to the drain;
- step 3 e DC current outputted from the program reference cell PFC is transformed as program reference cell bias voltage PGMBIAS by the program cell bit line voltage controller 850 of the program reference cell PFC.
- FIG. 9 shows a specific flow chart of the steps of programming a read reference cell in FIG. 6.
- the step 4 of programming the read reference cell RFC is explained in detail as follows:
- step 4 a internal power supply voltage VPD of which level is higher than that of external power supply voltage VDD is applied.
- the program bias voltage PRBIAS of 6V is applied to the bit line path of the read reference cell RFC through a positive terminal of the read cell bit line voltage controller 950 , a positive terminal of the comparator 970 is supplied with program reference cell bias voltage PGMBIAS outputted from the step 3 , and a negative terminal of the read cell bit line voltage controller 950 of the read reference cell RFC is supplied with a drain voltage of the read reference cell RFC applied through a plurality of read reference cell switches NM 110 to NM 11 n;
- step 4 b the third and fourth OP amplifiers are driven by the applied signal
- step 4 c a plurality of read cell gate selection signals RYG 0 to RYGn of high level, which are selectively applied for the bit line path of at least one read reference cell RFC, turn on a plurality of the read reference cell switches NM 110 to NM 11 n by selective switching, then the drain of the read reference cell RFC is supplied with 6V;
- step 4 d the read reference cell RFC is programmed by applying a read reference word line driving signal RWL;
- step 4 e as a level of bias voltage of the read reference cell RFC applied to the second comparator 970 becomes higher in the process of the programming the read reference cell RFC, the read program end signal RFPMEND of high level is outputted;
- step 4 f turning off the NMOS transistor NM 2 to cut off internal supply voltage VPD and eliminating charges that have been supplied to the bit line to stop diving the third OP amplifier with the read program end signal RFPMEND to terminate the programming of the read program reference cell RFC and to prevent from being programmed over-level which is unwanted by the read reference cell RFC.
- FIG. 10 shows a specific flow chart of the steps of generating reference voltage for the main cell programming in FIG. 6.
- the step 5 of generating reference voltage RDREF for programming the main cell MC is explained in detail as follows:
- step 5 a internal power supply voltage VPD of which level is higher than that of external power supply voltage VDD is applied.
- the program bias voltage of 6V is applied to the read program cell bit line voltage controller 950 of the read reference cell part 900 , and read bias voltage RDBIAS of 1.25V is applied to the program cell voltage controller 1111 ;
- step 5 b the third and seventh OP amplifiers are driven by the applied signal, while the fourth, fifth, and sixth OP amplifier is not driven.
- the NMOS transistors NM 2 and NM 4 are turned on by the driving of the third and seventh OP amplifiers;
- step 5 c a plurality of read reference cell switches NM 110 to NM 11 (n ⁇ 1) are turned on by selectively supplying a plurality of read cell gate selection signals RYG 0 to RYG(n ⁇ 1), which select the bit line path of the read reference cell RFC, of high level for selective switching.
- the read reference cell switch NM 11 n is turned off by supplying a read reference cell gate selection signal RYGn of low level, and all the program cell switches of the program reference cell part 800 are turned off;
- step 5 d when the program reference word line driving signal PWL is applied, the program reference cell PFC outputs fixed DC current to the bit line path of the read reference cell part 900 ;
- step 5 e DC current outputted from the program reference cell PFC is transformed as reference voltage RDREF by the read cell bit line voltage controller 950 of the read reference cell part 900 .
- FIG. 11 shows a specific flow chart of the steps of programming the main cell in FIG. 6.
- the step 6 of programming the main cell MC is explained in detail as follows:
- step 6 a internal power supply voltage VPD of which level is higher than that of external power supply voltage VDD is applied.
- the reference voltage RDREF outputted in the step 5 is applied to the sense amplifier 1566 , program bias voltage PRBIAS of 6V is applied to the bit line path of the main cell MC through a positive terminal of the main cell bit line voltage controller 1555 , and a positive terminal of the read cell bit line voltage controller 950 is supplied with program bias voltage PRBIAS of 6V;
- step 6 b the first and second OP amplifiers are driven by the applied signal
- step 6 c a plurality of main cell gate selection signals YGO to YGn of high level which are selectively applied for the bit line path of at least one main cell MC turn on a plurality of the main cell switches NM 100 to NM 10 n by selective switching, and the drain of the main cell MC is supplied with 6V;
- step 6 d the main cell MC is programmed by applying a main cell word line driving signal WL;
- step 6 e as a level of the bias voltage of the main cell MC applied to the sense amplifier 1566 becomes higher in the process of programming the main cell MC, the sense amplifier output SAOUT of high level is outputted;
- step 6 f turning off the NMOS transistor NM 1 to cut off internal supply voltage VPD and eliminating charges that have been supplied to the bit line to stopping driving the first and second OP amplifiers with the sense amplifier output SAOUT to terminate the programming the main cell MC and to prevent from being programmed over-level which is unwanted by the main cell MC.
- FIG. 12 shows a specific flow chart of the steps of reading the main cell in FIG. 6.
- the step 7 of reading the data stored in the main cell MC is explained in detail as follows:
- step 7 a internal power supply voltage VPD of which level is same as that of external power supply voltage VDD is applied.
- the main cell bit line voltage controller 1555 and read cell bit line voltage controller 950 are supplied with program bias voltage PRBIAS;
- step 7 b the first to third OP amplifiers OPA 1 , OPA 2 and OPA 3 are driven by the applied signal, while the fourth OP amplifier OPA 4 is not driven;
- step 7 c a plurality of main cell switches NM 100 to NM 10 n are turned on by selectively supplying a plurality of main cell gate selection signals YG 0 to YGn, which select the bit line path of at least one of the main cells MC, of high level for selective switching, and a plurality of read reference cell switches NM 110 to NM 11 n in are selectively turned on by supplying a plurality of read cell gate selection signals RYG 0 to RYGn, which selects the bit line paths of the read reference cell RFC, of high level;
- step 7 d the data stored in the main cell MC and read reference cell RFC are outputted by receiving a main cell word line driving signal WL and read reference word line driving signal RWL;
- step 7 e once the sense amplifier 1566 is supplied with an output SENSE, which is generated by transforming the current level outputted from the main cell MC into voltage, of the main cell path transistor and the reference voltage RDREF transformed from the current level of the read reference cell RFC by the cell bit line voltage controller 950 , the sense amplifier output SAOUT of low level is outputted when the output SENSE of the main cell path transistor is lower than the reference voltage RDREF. And, the sense amplifier output SAOUT becomes high level provided that the output SENSE is higher than the reference voltage RDREF.
- the operational process of the nonvolatile memory sensing circuit of multi-levels according to the present invention in FIG. 4 is almost the same in FIG. 6 to FIG. 12 but includes sense amplifier outputs SAOUT 1 to SAOUTn of N bits through a plurality of sense amplifiers 2333 , 2444 , and 2555 which compare the output of the main cell MC with a plurality of reference voltages RDREF 1 to RDREFn which are output of a plurality of reference cell part in the multi reference cell part 3000 .
- FIG. 5 The operational process of the nonvolatile memory sensing circuit of two levels according to another embodiment of the present invention in FIG. 5 is almost the same in FIG. 3.
- the embodiment in FIG. 5, comprising the main cell bit line voltage controller 4555 , program cell bit line voltage controller 3850 , and read cell bit line voltage controller 3950 having PMOS transistors, is able to carry out sensing operation, even if the internal power supply voltage level is decreased.
- the layout area of the circuit is reduced, when a reference cell part is being programmed or read, as drain or source voltage of a cell is controlled to a fixed level only by a program cell voltage controller.
- the voltage drop is prevented by using the same path of programming and reading, sufficient sensing margin is secured by preventing the voltage drop, and sensing capability is increased.
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Abstract
Description
- This application claims the benefit of Korean Patent Application No. 99-22494, filed on Jun. 16, 1999, which is hereby incorporated by reference.
- 1. Field of the Invention
- The present invention relates to semiconductor memory, more particularly, to nonvolatile memory sensing circuits and techniques thereof which improve the reference structure therein.
- 2. Background of the Related Art
- FIG. 1 shows a nonvolatile memory sensing circuit of two levels according to a related art, and FIG. 2 shows a nonvolatile memory sensing circuit of multi-levels according to a related art.
- Referring to FIG. 1, a
main cell array 110 including a main cell MC receives word line signals WL and selectively decodes the main cell. Avoltage clamp 130 rapidly charges a bit line of the main cell MC and maintains fixed voltage therein. Thevoltage clamp 130 includes two transistors NM2 and NM3 of which drains are connected to applied voltage VCC and asense amplifier 150 respectively, and an inverter INV1 which is connected commonly between sources and gates of the transistors NM2 and NM3. The inverter INV1 and NMOS transistor NM2 of which drain is connected to applied voltage VCC form a negative feed-back to the other NMOS transistor NM3 connecting the main cell to thesense amplifier 150, controlling drain voltage of another NMOS transistor NM1. - A
reference cell controller 120 supplies a gate of a reference cell RFC with drain voltage Vd, control gate voltage Vcg, and erasing gate voltage Veg or erases them. Namely, outputs of anerasing decoder 125 and aprogram decoder 123 are outputted to a reference cell RFC through a cell erasing orprogram selection circuit 121. Areference cell array 140 having the reference cell RFC provides thesense amplifier 150 with the criteria judging the data stored in the main cell MC through an NMOS transistor NM4 of which gate receives clock signals. - The
sense amplifier 150 which includes an NMOS transistor, PMOS transistors PM1 and PM2, and alatch part 151 produces the result SA by comparing the levels of the reference cell RFC and main cell MC. Applied voltage VCC is applied to sources of the PMOS transistors PM1 and PM2 having a common gate. A drain and gate of the PMOS transistor PM1 are connected to the reference cell RFC in common while a drain of the other PMOS transistor PM2 is connected to the main cell MC and a stage of an NMOS transistor NM5 of which gate receives a clock signal. Thelatch part 151 connected to the other stage of the NMOS transistor NM5 outputs the result therefrom. Thelatch part 151 includes a pair of inverters INV2 and INV3 which form a feed-back structure. Thesense amplifier 150, when the main cell MC is on the stage of reading operation, transforms the information of the reference cell RFC into reference voltage with the PMOS transistor PM1, then supplies the gate of the PMOS transistor PM2 with the reference voltage as gate voltage. Then, drain voltage of the PMOS transistor PM2 is transmitted to thelatch part 151 through the NMOS transistor NM5 when the clock signal is at “high”. - The operation of the nonvolatile memory sensing circuit of two levels of the related art is explained in the following description.
- The
cell controller 120 is in charge of the programming/erasing of the reference cell RFC in use of drain voltage Vd, control gate voltage Vcg, or erasing gate voltage Veg in accordance with each operational state. In read operation, once the clock signal CLK is enabled, the NMOS transistor NM4 is turned on. Thus, drain voltage of the PMOS transistor PM1 becomes reference voltage of the reference cell RFC since charges are transferred from applied voltage Vcc to the reference cell RFC. The same charges of the reference voltage applied to the gates of the PMOS transistors PM1 and PM2 of thesense amplifier 150 is also flown to the main cell MC because of the mirror phenomenon. In this case, the clock signal CLK is enabled and a read signal READ is applied. The NMOS transistor NM1 is turned on by receiving the word line signal WL to generate charge level of the main cell MC through thevoltage clamp 130 to thesense amplifier 150. When the charge flown through the main cell MC is less than the reference charge, the voltage applied to a source of the NMOS transistor NM5 is recognized as ‘high level’. When the charge flown through the main cell MC is greater than the reference charge, the voltage applied to the source of the NMOS transistor NM5 is recognized as ‘low level’. - A drain voltage of the NMOS transistor NM1 is kept at fixed level by means of the
fixed voltage clamp 130. Therefore, there is less chance that the main cell MC is exposed to bit line voltage and the sensitivity of the sense amplifier is increased to prevent the sensing operation being affected by the current variation of the main cell MC when the bit line is influenced by external factors on sensing. The result SA of the voltage level applied to the source of the NMOS transistor NM5 is outputted by thelatch part 151. - FIG. 2 shows a nonvolatile memory sensing circuit of multi-levels according to a related art. Referring to FIG. 2, a
main cell array 210 including a main cell MC receives word line signals WL and selectively decodes the main cell. A voltage clamp 230 rapidly charges a bit line of the main cell MC and maintains fixed voltage. A reference cell controller 220 supplies areference cell array 240 with drain voltage Vd, control gate voltage Vcg, and erasing gate voltage Veg. A cell erasing and program selection circuit 221 receiving an erasing signal Erase and programming signal Program which are decoded by an erasing decoder 225 and programming decoder 223, which decode the erasing gate voltage Veg in accordance with the erasing or programming operation, supplies areference cell array 240 with voltage of erasing or programming level. Various levels of a plurality of referencecells Ref Cell 1 to Ref Cell k in thereference cell array 240 are applied to asense amplifier 250 by the NMOS transistors N11 to N1k of which gates receive a plurality of clock signals CLK1 to CLKk, respectively. - The
sense amplifier 250, which includes PMOS transistors P1 and P2, a plurality of NMOS transistors N21 to N2k, and a plurality of latch parts, outputs the results SA1 to SAk by comparing the multi level of thereference cell array 250 to the level of the main cell MC. Applied voltage VCC is connected to sources of the PMOS transistors P1 and P2 which share a gate in common. A drain of the PMOS transistor P1 and the common gate are connected to a reference cell. A drain of the other PMOS transistor is connected to the main cell as well as a plurality of the NMOS transistors N21 to N2k of which gates receive a plurality of clock signals CLK1 to CLKk in parallel. - A plurality of latch parts connected to the other ends of the NMOS transistors N21 to N2k, respectively, produce the results SA1 to SAk. Each of the latch parts includes a pair of inverters forming a feed-back structure. The
decoder 260 outputs the final values Bit1 to BitL by decoding the results SA1 to SAk produced by thesense amplifier 250. The nonvolatile memory sensing circuit of multi-levels according to the related art shows the same operation as that of the circuit of two levels, except for having thereference cell array 240 consist of a plurality of referencecells Ref Cell 1 to Ref Cellk and programming various k number of reference voltages to sense the multi-levels of k+1. - In reading operation, when a plurality of the clock signals CLK1 to CLKk are enabled in order, the
sense amplifier 250 supplied with charge levels of a plurality of the reference cells Ref Cell1 to Ref Cellk and the main cell MC stores the results in a plurality of thelatch parts 151 by comparing the multi-levels of thereference cell array 240 to the level of the main cell MC. After the operations by the clock signals CLK1 to CLKk have been completed successively, the results SA1 to SAk are produced to thedecoder 260. Then, thedecoder 260 outputs the final values Bit1 to BitL by judging the data of the main cell MC by decoding the results SA1 to SAk outputted by thesense amplifier 250. - Unfortunately, both of the memory sensing circuits of two and multi-levels according to the related art require an additional controller such as program control means and read control means for the main and reference cell programs and for reading the main or reference cell. When the reference cell is programmed in use of a programming means, voltage offset of the programming means occurs. The voltage offset is caused by the variations of fabrication due to temperature, pressure, and the like. Thus, voltage offset of the program controller is inevitable when the reference cell is programmed.
- Moreover, the sensing margin is decreased by the influence on the reference cell due to the voltage offset of the reading control means when the reference cell is read by the reading control means, thereby causing the direct fail in the precise reading operation of the memory sensing circuit of multi-levels of which reading margin is basically less than that of two levels.
- Accordingly, the present invention is directed to nonvolatile memory sensing circuits and techniques thereof that substantially obviate one or more problems due to limitations and disadvantages of the related art.
- An object of the present invention is to provide nonvolatile memory sensing circuits and techniques thereof which improve the reference structure for securing the sensing margin on reading by canceling out the voltage offset reflected on the main or reference cell.
- Additional features and advantages of the invention will be set forth in the description which follows and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
- To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the present invention of a nonvolatile memory sensing circuit including a main cell part and at least one reference cell part, comprises a main cell array having a plurality of main cells to which word line driving signal is applied respectively, a plurality of main cell switches receiving a plurality of main cell selection signals YG0 to YGn which switch to select one of the main cells, respectively, wherein the main cell switches are connected to the main cell array in series, a main cell bit line voltage controller maintaining drain voltage at a fixed level by receiving program bias voltage PRBIAS, a main cell path transistor connected between an output of the main cell bit line voltage controller and internal power supply voltage, wherein the main cell path transistor outputs a state of the main cell, and at least one sense amplifier producing a comparison output SAOUT by receiving at least one reference voltage RDREF and an output SENSE of the main cell path transistor, wherein the reference cell part further comprises program reference cell part and read reference cell part which sharing a voltage controlling means for regulating drain or source voltage to a predetermined level and producing the reference voltage RDREF of fixed level.
- In another aspect, the present invention includes a method of operating a nonvolatile memory sensing circuit comprising the steps of driving a memory sensing means by applying internal power supply voltage VPD and external power supply voltage VDD, programming a program reference cell PFC, generating program reference cell bias voltage PGMBIAS for programming a read reference cell RFC, programming the read reference cell RFC, generating reference voltage RDREF for programming a main cell MC, programming the main cell MC by using the reference voltage RDREF, and reading data stored in the main cell MC, wherein drain or source voltage of the program reference cell and read reference cell is maintained at a predetermined level by a common means when programming or reading is carried out.
- It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
- The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the inventing and together with the description serve to explain the principle of the invention.
- In the drawings:
- FIG. 1 shows a nonvolatile memory sensing circuit of two levels according to a related art;
- FIG. 2 shows a nonvolatile memory sensing circuit of multi-levels according to a related art;
- FIG. 3 shows a nonvolatile memory sensing circuit of two levels according to the present invention;
- FIG. 4 shows a nonvolatile memory sensing circuit of multi-levels according to the present invention;
- FIG. 5 shows a nonvolatile memory sensing circuit of two levels according to another embodiment of the present invention;
- FIG. 6 shows a flow chart of operation of the nonvolatile sensing memory circuit of two levels according to another embodiment of the present invention;
- FIG. 7 shows a specific flow chart of the steps of programming a program reference cell in FIG. 6.;
- FIG. 8 shows a specific flow chart of the steps of generating program reference cell bias voltage in FIG. 6;
- FIG. 9 shows a specific flow chart of the steps of programming a read reference cell in FIG. 6;
- FIG. 10 shows a specific flow chart of the steps of generating reference voltage for a main cell programming in FIG. 6;
- FIG. 11 shows a specific flow chart of the steps of programming the main cell in FIG. 6; and
- FIG. 12 shows a specific flow chart of the steps of reading the main cell in FIG. 6.
- Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
- FIG. 3 shows a nonvolatile memory sensing circuit of two levels according to the present invention. Referring to FIG. 3, the nonvolatile memory sensing circuit of two levels according to the present invention is comprised of a
main cell part 1500 and areference cell part 1000. Thereference cell part 1000 consists of a program reference cell part 800 and read reference cell part 900 which connected to a common means for controlling drain and source voltage to predetermined level on programming or reading. - The
main cell part 1500 is comprised of amain cell array 1550 including a plurality of main cells MC receiving word line driving signals respectively, a plurality of main cell switches NM100 to NM10n receiving a plurality of main cell selection signals YG0 to YGn, respectively, which selects one of the main cells MC and connected to themain cell array 1550, a main cell bitline voltage controller 1555 maintaining drain voltage of the main cell MC by receiving program bias voltage PRBIAS, a main cell path transistor MP101 which is connected between the main cellbit line controller 1555 and internal power supply voltage VPD and which outputs the state of the main cell, and asense amplifier 1566 which receives an output SENSE and reference voltage RDREF of the main cell path transistor and generates an output by comparing the SENSE and the RDREF. - A program reference cell part800 includes at least one program reference cell PFC receiving a program reference word line driving signal PWL, a program
cell voltage controller 1111 adjusting drain voltage of the program reference cells to the level under external power supply voltage VDD by receiving read bias voltage RDBIAS, a plurality of program cell switches NM120 to NM12n which are connected to an output of the programcell voltage controller 1111 in series and which receive a plurality of program cell gate selection signals PYG0 to PYGn selecting one of the program reference cells PFC, a program cell bitline voltage controller 850 maintaining proper drain voltage when the program reference cell is programmed or read by receiving the program bias voltage PRBIAS, a program reference cell path transistor MP103 which is connected between an output of the program cell bitline voltage controller 850 and internal power supply voltage VPD and generates program reference cell bias voltage PGMBIAS, and afirst comparator 870 outputting a program end signal PFPMEND by comparing the program reference cell bias voltage PGMBIAS to the program reference voltage PGMREF. - The read reference cell part900 is comprised of at least one read reference cell RFC receiving a read word line driving signal RWL, a plurality of read reference cell switches NM110 to NM11n which receive an output of the program
cell voltage controller 1111 of the program reference cell part 800 as well as a plurality of read cell gate selection signals RYG0 to RYGn selecting one of the read reference cells RFC and which are connected to the read reference cell RFC in series, a read cell bitline voltage controller 950 maintaining drain voltage at proper fixed level when the read reference cell is programmed or read by receiving program bias voltage PRBIAS, a read reference cell path transistor MP102 which is connected between the read cell bitline voltage controller 950 and internal power supply voltage VPD and generates reference voltage RDREF, and asecond comparator 970 outputting a read program end signal RFPMEND by comparing reference voltage RDREF to the output PGMBIAS of the program reference cell path transistor. - The main cell bit
line voltage controller 1555 is comprised of a first OP amplifier OPA1 outputting a main cell voltage regulating signal reg1 wherein program bias voltage PRBIAS is inputted to a positive terminal and drain voltage applied through a plurality of main cell switches NM100 to NM10n is inputted to a negative terminal, and an NMOS transistor NM1 of which gate is supplied with the main cell voltage regulating signal reg1 wherein a drain is connected to the main cell switches and a source is connected to the main cell path transistor MP101. - The
sense amplifier 1566 consists of a second OP amplifier OPA2 outputting a result SAOUT by receiving internal power supply voltage VPD wherein an output SENSE of the main cell path transistor is inputted to a negative terminal and reference voltage RDREF is inputted to a positive terminal. - The program cell bit
line voltage controller 850 is comprised of a fifth OP amplifier OPA5 outputting a program cell voltage regulating signal reg3 by receiving internal power supply voltage wherein program bias voltage PRBIAS is inputted to a positive terminal and drain voltage of the program reference cell applied by a plurality of program cell switches NM120 to NM12n is inputted to a negative terminal and an NMOS transistor NM3 wherein a drain is connected to the NMOS switches, a source is connected to the program reference cell path transistor MP103, and the gate is supplied with the program cell voltage regulating signal reg3. - The read cell bit
line voltage controller 950 is comprised of a third OP amplifier OPA3 outputting the read voltage regulating signal reg2 by receiving internal power supply voltage VPD wherein program bias voltage PRBIAS is inputted to a positive terminal and a drain voltage of the read reference cell RFC applied through a plurality of read reference cell switches NM110 to NM1n is inputted to a negative terminal and an NMOS transistor NM2 wherein a drain is connected to the read reference cell switches NM1 10 to NM1 in, a source is connected to the read reference cell path transistor MP102, and a gate is supplied with the program cell voltage regulating signal reg2. - The
first comparator 870 consists of a sixth OP amplifier OPA6 outputting the program end signal PFPMEND by receiving internal power supply voltage VPD wherein the program reference cell bias voltage PGMBIAS is inputted to a negative terminal and the program reference voltage PGMREF is inputted to a positive terminal. - The
second comparator 970 consists of a fourth OP amplifier OPA4 outputting the read program end signal RFPMEND by receiving internal power supply voltage VPD wherein the program reference cell bias voltage PGMBIAS is inputted to a positive terminal and the reference voltage RDREF is inputted to a negative terminal. - The program
cell voltage controller 1111 is comprised of an OP amplifier outputting a voltage regulating signal reg4 by receiving external power supply voltage VDD wherein drain voltage of the program reference cell PFC is inputted to a negative terminal and read bias voltage RDBIAS is inputted to a positive terminal and an NMOS transistor NM4 of which source and drain are shared by those of the program cell switches NM120 to NM12n respectively wherein a voltage regulating signal reg4 is inputted to a gate of the transistor NM4. - The main cell path transistor MP101, program reference cell path transistor MP103, and read reference cell path transistor MP102, of which sources are supplied with internal power supply voltage VPD, consist of PMOS transistors of which sources are supplied with internal power supply voltage VPD and which have common gates and drains.
- FIG. 4 shows a nonvolatile memory sensing circuit of multi-levels according to the present invention. Referring to FIG. 4, the nonvolatile memory sensing circuit of multi-levels of the present invention is comprised of a multi
main cell part 2000 and a multireference cell part 3000. The multireference cell part 3000 includes a plurality ofreference cell parts 1000 which produce different reference voltage RDREF1 to RDREFn, respectively. - The multi
main cell part 2000 includes a plurality of multi main cell switches NM200 to NM20n which are connected in series to a plurality of main cells MC receiving a word line driving signal WL, respectively, and are supplied with a plurality of main cell selection signals YG0 to YGn, a multi main cell bitline voltage controller 2111 maintaining drain voltage of the main cell to fixed level by receiving program bias voltage PRBIAS, a main cell path transistor MP201 which is connected between an output of the multi main cell bitline voltage controller 2111 and internal power supply voltage VPD and generate a state of the main cell, and a plurality ofsense amplifiers - FIG. 5 shows a nonvolatile memory sensing circuit of two levels according to another embodiment of the present invention. Referring to FIG. 5, the nonvolatile memory sensing circuit of two levels of the present invention is comprised of a
main cell part 4500 and areference cell part 4000. Thereference cell part 4000 is comprised of a programreference cell part 3800 and readreference cell part 3900 which shares a control means regulating drain or source voltage of a cell on programming or reading. - The
main cell part 4500 includes amain cell array 4550 including a plurality of main cells MC receiving a word line driving signal WL, respectively, a plurality of main cell switches NM400 to NM40n which are connected in series to themain cell array 4550 and are supplied with a plurality of main cell selection signals YGO to YGn selecting one of the main cells, a main cell bitline voltage controller 4555 maintaining drain voltage of the main cell to fixed level by receiving program bias voltage PRBIAS, a main cell path transistor MP301 which is connected between an output of the main cell bitline voltage controller 4555 and internal power supply voltage VPD and generate a state of the main cell, and asense amplifier 4566 producing comparison outputs by receiving an output SENSE of the main cell path transistor and reference voltage RDREF. - The program
reference cell part 3800 includes at least one program reference cell PFC receiving a program reference word line driving signal PWL, a programcell voltage controller 2222 adjusting drain voltage of the program reference cells PFC to the level under external power supply voltage VDD by receiving read bias voltage RDBIAS, a plurality of program cell switches NM440 to NM44n which are connected in series to an output of the programcell voltage controller 2222 and which receive a plurality of program cell gate selection signals PYG0 to PYGn selecting one of the program reference cells PFC, a program cell bitline voltage controller 3850 maintaining proper level of drain voltage when the program reference cell is programmed or read by receiving the program bias voltage PRBIAS, a program reference cell path transistor which is connected between an output of the program cell bitline voltage controller 3850 and internal power supply voltage VPD and generates program reference cell bias voltage PGMBIAS, and afirst comparator 3870 outputting a program end signal PFPMEND by comparing the program reference cell bias voltage PGMBIAS to the program reference voltage PGMREF. - The read
reference cell part 3900 is comprised of at least one read reference cell RFC receiving a read word line driving signal RWL, a plurality of read reference cell switches NM420 to NM42n which receive an output of the programcell voltage controller 2222 of the programreference cell part 3800 as well as a plurality of read cell gate selection signals RYG0 to RYGn selecting one of the read reference cells RFC and which are connected to the read reference cell RFC in series, a read cell bitline voltage controller 3950 maintaining drain voltage to proper fixed level when the read reference cell is programmed or read by receiving program bias voltage PRBIAS, a read reference cell path transistor which is connected between the read cell bitline voltage controller 3950 and internal power supply voltage VPD and generates reference voltage RDREF, and asecond comparator 3970 outputting a read program end signal RFPMEND by comparing reference voltage RDREF to the output PGMBIAS of the program reference cell path transistor. - The main cell bit
line voltage controller 4555 is comprised of an 101th OP amplifier OPA101 outputting a main cell voltage regulating signal reg1 wherein program bias voltage PRBIAS is inputted to a positive terminal and drain voltage applied through a plurality of main cell switches NM400 to NM40n is inputted to a negative terminal and a PMOS transistor PM311 of which gate is supplied with the main cell voltage regulating signal reg1 wherein a drain is connected to the main cell switches and a source is connected to the main cell path transistor. - The
sense amplifier 4566 consists of an 102th OP amplifier OPA102 outputting a result SAOUT by receiving internal power supply voltage VPD wherein an output SENSE of the main cell path transistor is inputted to a negative terminal and reference voltage RDREF is inputted to a positive terminal. - The program cell bit
line voltage controller 3850 is comprised of an 105th OP amplifier OPA105 outputting a program cell voltage regulating signal reg3 by receiving internal power supply voltage wherein program bias voltage PRBIAS is inputted to a positive terminal and drain voltage of the program reference cell applied by a plurality of program cell switches NM440 to NM44n is inputted to a negative terminal and a PMOS transistor PM313 wherein a drain is connected to the drain of the program cell switch NM440, a source is connected to the program reference cell path transistor, and the gate is supplied with the program cell voltage regulating signal reg3. - The read cell bit
line voltage controller 3950 is comprised of an 103th OP amplifier OPA103 outputting a read voltage regulating signal reg2 by receiving internal power supply voltage VPD wherein program bias voltage PRBIAS is inputted to a positive terminal and a drain voltage of the read reference cell RFC applied through a plurality of read reference cell switches NM420 to NM42n is inputted to a negative terminal and a PMOS transistor PM312 wherein a drain is connected to the read reference cell switches NM420 to NM42n, a source is connected to the read reference cell path transistor, and a gate is supplied with the program cell voltage regulating signal reg2. - The
first comparator 3870 consists of an 106th OP amplifier OPA106 outputting the program end signal PFPMEND by receiving internal power supply voltage VPD wherein the program reference cell bias voltage PGMBIAS is inputted to a negative terminal and the program reference voltage PGMREF is inputted to a positive terminal. - The
second comparator 3970 consists of an 104th OP amplifier OPA104 outputting the read program end signal RFPMEND by receiving internal power supply voltage VPD wherein the program reference cell bias voltage PGMBIAS is inputted to a positive terminal and the reference voltage RDREF is inputted to a negative terminal. - The program
cell voltage controller 2222 is comprised of an 107th OP amplifier OPA107 outputting a voltage regulating signal reg4 by receiving external power supply voltage VDD wherein drain voltage of the program reference cell PFC is inputted to a negative terminal and read bias voltage RDBIAS is inputted to a positive terminal and an NMOS transistor NM300 of which source and drain are shared by those of the program cell switches NM440 to NM44n respectively wherein the voltage regulating signal reg4 is inputted to a gate of the transistor NM300. - The main cell path transistor, program reference cell path transistor, and read reference cell path transistor, of which sources are supplied with internal power supply voltage VPD, consist of PMOS transistors of which sources are supplied with internal power supply voltage VPD and which have common gates and drains.
- A sensing method of nonvolatile memory in use of the nonvolatile memory sensing circuit of the present invention in FIG. 3 will be explained in the following description.
- FIG. 6 shows a flow chart of operation of the nonvolatile sensing memory circuit of two levels according to the present invention. The steps of the operation of the nonvolatile memory sensing circuit according to the present invention are as follows:
-
step 1, a memory sensing circuit is driven by applying internal and external power supply voltages VPD and VDD; -
step 2, a program reference cell PFC is programmed; -
step 3, program reference cell bias voltage PGMBIAS is produced to program a read reference cell RFC; - step4, the read reference cell RFC is programmed;
-
step 5, reference voltage RDREF is produced to program a main cell; -
step 6, the main cell is programmed by using the reference voltage RDREF; and -
step 7, data stored in the main cell is read. - FIG. 7 shows a specific flow chart of the steps of programming the program reference cell in FIG. 6. The
step 2 in FIG. 6 is explained in detail as follows: -
step 2 a, internal power supply voltage VPD of which a level is higher than a level of external power supply voltage VDD is applied. Thefirst comparator 870 is supplied with program reference voltage PGMREF, and program bias voltage of 6V is applied to a positive terminal of the program cell bitline voltage controller 850 of the program reference cell PFC; -
step 2 b, the fifth and sixth OP amplifiers are driven by the applied signal, while the seventh OP amplifier is not driven; -
step 2 c, a plurality of program cell gate selection signals PYG0 to PYG(n−1) which are selectively applied for the bit line path of at least one program reference cell PFC turns on a plurality of the program cell switches NM120 to NM12(n−1) by selective switching. The program cell gate selection signal PYGn of high level is applied to turn on the program cell switch NM12n and the drain of the program reference cell PFC is supplied with 6V; -
step 2 d, the program reference cell PFC is programmed as the program reference word line driving signal PWL is applied; -
step 2 e, as a level of the program reference cell bias voltage PGMBIAS applied to thefirst comparator 870 becomes higher in the process of the programming the program reference cell PFC, the program end signal PFPMEND of high level is outputted; and -
step 2 f, turning off the NMOS transistor NM3 to cut off internal supply voltage VPD and eliminating charges that have been supplied to the bit line to stop diving the fifth OP amplifier with the program end signal PFPMEND to terminate the programming of the program reference cell PFC and to prevent from being programmed over-level which is unwanted by the program reference cell PFC. - FIG. 8 shows a specific flow chart of the steps of generating program reference cell bias voltage in FIG. 6. The
step 3 of generating program reference cell bias voltage PGMBIAS to program a read reference cell RFC further includes the steps of: -
step 3 a, internal power supply voltage VPD of which level is higher than that of external power supply voltage VDD is applied. The program bias voltage of 6V is applied to the program cell bitline voltage controller 850 of the program reference cell PFC, and read bias voltage of 1.25V is applied to the programcell voltage controller 1111; -
step 3 b, the fifth and seventh OP amplifiers are driven by the applied signal, while the sixth amplifier is not driven; -
step 3 c, a plurality of program cell switches NM120 to NM12(n−1) are turned on selectively by supplying a plurality of program cell gate selection signals PYG0 to PYG(n−1), which select the bit line path of the program reference cell PFC, of high level for selective switching. The program cell switch NM12n is turned off by supplying a program cell gate selection signal PYGn of low level; -
step 3 d, when the program reference word line driving signal PWL is applied, the program reference cell PFC which is not programmed outputs fixed DC current to the drain; and -
step 3 e, DC current outputted from the program reference cell PFC is transformed as program reference cell bias voltage PGMBIAS by the program cell bitline voltage controller 850 of the program reference cell PFC. - FIG. 9 shows a specific flow chart of the steps of programming a read reference cell in FIG. 6. The step4 of programming the read reference cell RFC is explained in detail as follows:
-
step 4 a, internal power supply voltage VPD of which level is higher than that of external power supply voltage VDD is applied. The program bias voltage PRBIAS of 6V is applied to the bit line path of the read reference cell RFC through a positive terminal of the read cell bitline voltage controller 950, a positive terminal of thecomparator 970 is supplied with program reference cell bias voltage PGMBIAS outputted from thestep 3, and a negative terminal of the read cell bitline voltage controller 950 of the read reference cell RFC is supplied with a drain voltage of the read reference cell RFC applied through a plurality of read reference cell switches NM110 to NM11n; -
step 4 b, the third and fourth OP amplifiers are driven by the applied signal; -
step 4 c, a plurality of read cell gate selection signals RYG0 to RYGn of high level, which are selectively applied for the bit line path of at least one read reference cell RFC, turn on a plurality of the read reference cell switches NM110 to NM11n by selective switching, then the drain of the read reference cell RFC is supplied with 6V; -
step 4 d, the read reference cell RFC is programmed by applying a read reference word line driving signal RWL; -
step 4 e, as a level of bias voltage of the read reference cell RFC applied to thesecond comparator 970 becomes higher in the process of the programming the read reference cell RFC, the read program end signal RFPMEND of high level is outputted; and -
step 4 f, turning off the NMOS transistor NM2 to cut off internal supply voltage VPD and eliminating charges that have been supplied to the bit line to stop diving the third OP amplifier with the read program end signal RFPMEND to terminate the programming of the read program reference cell RFC and to prevent from being programmed over-level which is unwanted by the read reference cell RFC. - FIG. 10 shows a specific flow chart of the steps of generating reference voltage for the main cell programming in FIG. 6. The
step 5 of generating reference voltage RDREF for programming the main cell MC is explained in detail as follows: -
step 5 a, internal power supply voltage VPD of which level is higher than that of external power supply voltage VDD is applied. The program bias voltage of 6V is applied to the read program cell bitline voltage controller 950 of the read reference cell part 900, and read bias voltage RDBIAS of 1.25V is applied to the programcell voltage controller 1111; -
step 5 b, the third and seventh OP amplifiers are driven by the applied signal, while the fourth, fifth, and sixth OP amplifier is not driven. The NMOS transistors NM2 and NM4 are turned on by the driving of the third and seventh OP amplifiers; -
step 5 c, a plurality of read reference cell switches NM110 to NM11(n−1) are turned on by selectively supplying a plurality of read cell gate selection signals RYG0 to RYG(n−1), which select the bit line path of the read reference cell RFC, of high level for selective switching. The read reference cell switch NM11n is turned off by supplying a read reference cell gate selection signal RYGn of low level, and all the program cell switches of the program reference cell part 800 are turned off; -
step 5 d, when the program reference word line driving signal PWL is applied, the program reference cell PFC outputs fixed DC current to the bit line path of the read reference cell part 900; and -
step 5 e, DC current outputted from the program reference cell PFC is transformed as reference voltage RDREF by the read cell bitline voltage controller 950 of the read reference cell part 900. - FIG. 11 shows a specific flow chart of the steps of programming the main cell in FIG. 6. The
step 6 of programming the main cell MC is explained in detail as follows: -
step 6 a, internal power supply voltage VPD of which level is higher than that of external power supply voltage VDD is applied. The reference voltage RDREF outputted in thestep 5 is applied to thesense amplifier 1566, program bias voltage PRBIAS of 6V is applied to the bit line path of the main cell MC through a positive terminal of the main cell bitline voltage controller 1555, and a positive terminal of the read cell bitline voltage controller 950 is supplied with program bias voltage PRBIAS of 6V; -
step 6 b, the first and second OP amplifiers are driven by the applied signal; -
step 6 c, a plurality of main cell gate selection signals YGO to YGn of high level which are selectively applied for the bit line path of at least one main cell MC turn on a plurality of the main cell switches NM100 to NM10n by selective switching, and the drain of the main cell MC is supplied with 6V; -
step 6 d, the main cell MC is programmed by applying a main cell word line driving signal WL; -
step 6 e, as a level of the bias voltage of the main cell MC applied to thesense amplifier 1566 becomes higher in the process of programming the main cell MC, the sense amplifier output SAOUT of high level is outputted; and - step6 f, turning off the NMOS transistor NM1 to cut off internal supply voltage VPD and eliminating charges that have been supplied to the bit line to stopping driving the first and second OP amplifiers with the sense amplifier output SAOUT to terminate the programming the main cell MC and to prevent from being programmed over-level which is unwanted by the main cell MC.
- FIG. 12 shows a specific flow chart of the steps of reading the main cell in FIG. 6. The
step 7 of reading the data stored in the main cell MC is explained in detail as follows: -
step 7 a, internal power supply voltage VPD of which level is same as that of external power supply voltage VDD is applied. The main cell bitline voltage controller 1555 and read cell bitline voltage controller 950 are supplied with program bias voltage PRBIAS; -
step 7 b, the first to third OP amplifiers OPA1, OPA2 and OPA3 are driven by the applied signal, while the fourth OP amplifier OPA4 is not driven; -
step 7 c, a plurality of main cell switches NM100 to NM10n are turned on by selectively supplying a plurality of main cell gate selection signals YG0 to YGn, which select the bit line path of at least one of the main cells MC, of high level for selective switching, and a plurality of read reference cell switches NM110 to NM11n in are selectively turned on by supplying a plurality of read cell gate selection signals RYG0 to RYGn, which selects the bit line paths of the read reference cell RFC, of high level; -
step 7 d, the data stored in the main cell MC and read reference cell RFC are outputted by receiving a main cell word line driving signal WL and read reference word line driving signal RWL; and -
step 7 e, once thesense amplifier 1566 is supplied with an output SENSE, which is generated by transforming the current level outputted from the main cell MC into voltage, of the main cell path transistor and the reference voltage RDREF transformed from the current level of the read reference cell RFC by the cell bitline voltage controller 950, the sense amplifier output SAOUT of low level is outputted when the output SENSE of the main cell path transistor is lower than the reference voltage RDREF. And, the sense amplifier output SAOUT becomes high level provided that the output SENSE is higher than the reference voltage RDREF. - The operational process of the nonvolatile memory sensing circuit of multi-levels according to the present invention in FIG. 4 is almost the same in FIG. 6 to FIG. 12 but includes sense amplifier outputs SAOUT1 to SAOUTn of N bits through a plurality of
sense amplifiers reference cell part 3000. - The operational process of the nonvolatile memory sensing circuit of two levels according to another embodiment of the present invention in FIG. 5 is almost the same in FIG. 3. However, the embodiment in FIG. 5, comprising the main cell bit
line voltage controller 4555, program cell bitline voltage controller 3850, and read cell bitline voltage controller 3950 having PMOS transistors, is able to carry out sensing operation, even if the internal power supply voltage level is decreased. - In the present invention, the layout area of the circuit is reduced, when a reference cell part is being programmed or read, as drain or source voltage of a cell is controlled to a fixed level only by a program cell voltage controller. The voltage drop is prevented by using the same path of programming and reading, sufficient sensing margin is secured by preventing the voltage drop, and sensing capability is increased.
- It will be apparent to those skilled in the art that various modifications and variations can be made in nonvolatile memory sensing circuits and techniques thereof of the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and equivalents.
Claims (20)
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US09/901,898 US6445616B2 (en) | 1999-06-16 | 2001-07-11 | Nonvolatile memory sensing circuit and techniques thereof |
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KR1019990022494A KR100300549B1 (en) | 1999-06-16 | 1999-06-16 | Nonvolatile Memory Sensing Circuits And Techniques |
KR99-22494 | 1999-06-16 | ||
US09/590,071 US6292397B1 (en) | 1999-06-16 | 2000-06-09 | Nonvolatile memory sensing circuit and techniques thereof |
US09/901,898 US6445616B2 (en) | 1999-06-16 | 2001-07-11 | Nonvolatile memory sensing circuit and techniques thereof |
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US09/590,071 Division US6292397B1 (en) | 1999-06-16 | 2000-06-09 | Nonvolatile memory sensing circuit and techniques thereof |
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US09/901,898 Expired - Lifetime US6445616B2 (en) | 1999-06-16 | 2001-07-11 | Nonvolatile memory sensing circuit and techniques thereof |
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Cited By (1)
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CN107958688A (en) * | 2016-10-17 | 2018-04-24 | 旺宏电子股份有限公司 | The sensing circuit and method of Nonvolatile memory devices |
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TW419828B (en) * | 1997-02-26 | 2001-01-21 | Toshiba Corp | Semiconductor integrated circuit |
US6459620B1 (en) * | 2001-06-21 | 2002-10-01 | Tower Semiconductor Ltd. | Sense amplifier offset cancellation in non-volatile memory circuits by dedicated programmed reference non-volatile memory cells |
JP4144784B2 (en) * | 2002-07-30 | 2008-09-03 | シャープ株式会社 | Read circuit of semiconductor memory device, reference circuit thereof, and semiconductor memory device |
ITTO20030121A1 (en) * | 2003-02-18 | 2004-08-19 | St Microelectronics Srl | NON VOLATILE MEMORY CELL READING AMPLIFIER A |
US6775186B1 (en) | 2003-07-03 | 2004-08-10 | Tower Semiconductor Ltd. | Low voltage sensing circuit for non-volatile memory device |
CN100375195C (en) * | 2003-10-24 | 2008-03-12 | 上海宏力半导体制造有限公司 | Sensing amplifier for photoetching read-only memory |
KR100618840B1 (en) * | 2004-06-29 | 2006-09-01 | 삼성전자주식회사 | Sense circuit for low power supply voltage flash memory device |
ITMI20042074A1 (en) * | 2004-10-29 | 2005-01-29 | St Microelectronics Srl | CURRENT READING AMPLIFIER FOR LOW VOLTAGE APPLICATIONS WITH DIRECT SENSING ON THE BITLINE OF A MEMORY MATRIX |
US7082061B2 (en) * | 2004-12-03 | 2006-07-25 | Macronix International Co., Ltd. | Memory array with low power bit line precharge |
US7082069B2 (en) * | 2004-12-03 | 2006-07-25 | Macronix International Co., Ltd. | Memory array with fast bit line precharge |
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KR100735010B1 (en) | 2005-09-08 | 2007-07-03 | 삼성전자주식회사 | Flash memory device and voltage generating circuit for the same |
KR100866623B1 (en) * | 2006-10-16 | 2008-11-03 | 삼성전자주식회사 | Sense Amplifying Circuit and Nonvolatile Memory Device capable of operating with low power supply |
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US8497710B2 (en) * | 2011-05-16 | 2013-07-30 | National Tsing Hua University | Low-offset current-sense amplifier and operating method thereof |
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JP3132637B2 (en) * | 1995-06-29 | 2001-02-05 | 日本電気株式会社 | Nonvolatile semiconductor memory device |
JP2800740B2 (en) * | 1995-09-28 | 1998-09-21 | 日本電気株式会社 | Semiconductor storage device |
KR100339024B1 (en) * | 1998-03-28 | 2002-09-18 | 주식회사 하이닉스반도체 | Sense amp. circuit for flash memory device |
JP3346274B2 (en) * | 1998-04-27 | 2002-11-18 | 日本電気株式会社 | Nonvolatile semiconductor memory device |
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KR100331549B1 (en) * | 1999-08-06 | 2002-04-06 | 윤종용 | Current Sense Amplifier Circuit using Dummy Bit Line |
-
1999
- 1999-06-16 KR KR1019990022494A patent/KR100300549B1/en not_active IP Right Cessation
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2000
- 2000-06-09 US US09/590,071 patent/US6292397B1/en not_active Expired - Lifetime
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CN107958688A (en) * | 2016-10-17 | 2018-04-24 | 旺宏电子股份有限公司 | The sensing circuit and method of Nonvolatile memory devices |
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US6292397B1 (en) | 2001-09-18 |
US6445616B2 (en) | 2002-09-03 |
KR100300549B1 (en) | 2001-11-01 |
KR20010002603A (en) | 2001-01-15 |
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