US20160358665A1 - Programming verification control circuit and method for control thereof - Google Patents
Programming verification control circuit and method for control thereof Download PDFInfo
- Publication number
- US20160358665A1 US20160358665A1 US14/976,704 US201514976704A US2016358665A1 US 20160358665 A1 US20160358665 A1 US 20160358665A1 US 201514976704 A US201514976704 A US 201514976704A US 2016358665 A1 US2016358665 A1 US 2016358665A1
- Authority
- US
- United States
- Prior art keywords
- voltage
- memory bit
- signal
- gate
- receiving
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- G11C16/34—Determination of programming status, e.g. threshold voltage, overprogramming or underprogramming, retention
- G11C16/3436—Arrangements for verifying correct programming or erasure
- G11C16/3454—Arrangements for verifying correct programming or for detecting overprogrammed cells
- G11C16/3459—Circuits or methods to verify correct programming of nonvolatile memory 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
- G11C16/04—Erasable programmable read-only memories electrically programmable using variable threshold transistors, e.g. FAMOS
- G11C16/0408—Erasable programmable read-only memories electrically programmable using variable threshold transistors, e.g. FAMOS comprising cells containing floating gate transistors
- G11C16/0441—Erasable programmable read-only memories electrically programmable using variable threshold transistors, e.g. FAMOS comprising cells containing floating gate transistors comprising cells containing multiple floating gate devices, e.g. separate read-and-write FAMOS transistors with connected floating gates
- G11C16/0458—Erasable programmable read-only memories electrically programmable using variable threshold transistors, e.g. FAMOS comprising cells containing floating gate transistors comprising cells containing multiple floating gate devices, e.g. separate read-and-write FAMOS transistors with connected floating gates comprising two or more independent floating gates which store independent data
-
- 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
- G11C16/08—Address circuits; Decoders; Word-line control circuits
-
- 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
- G11C16/10—Programming or data input circuits
Definitions
- the present invention relates to verification of programming of a memory device and, in particular, to programming verification control circuits and methods for control thereof.
- flash memories As a kind of integrated circuit (IC) memory devices, flash memories have the function of storing information in an electrically erasable and rewritable manner. For this reason, flash memories are widely used in electronic products including portable computers, cell phones and digital music players.
- a flash memory has many memory cells that are required to be so arranged as to be adapted to its operations. Each of the memory cells stores a single bit of data.
- FIG. 1 schematically illustrates a memory cell of a conventional flash memory device
- FIG. 2 shows an array of memory cells of the conventional device.
- the flash memory device includes a plurality of the arrayed memory cells, as well as a plurality of bit lines (BL0, BL1, BL2, BL.3, . . , , and BLm), a plurality of word lines (WL) and a plurality of control gates (e.g., CG 0 , CB 1 and so forth), configured to select and provide drive signals to the individual memory cells.
- each of the memory cells includes two memory bits, i.e., bits A and B, and a word line common to the two bits.
- Each of the memory bits includes a bit line and a control gate. While only two control gates are depicted in FIG. 2 , i.e., CG 0 and CG 1 , in practical, the memory may have more control gates (i.e., CG 0 , CG 1 , CG 2 , CG 3 , . . . , and CGn), as generally and commonly known in this art, and a detailed description thereof is therefore omitted herein.
- programming verification is generally carried out by reading the memory bit. This process is explained below with the programming of the memory bit A as an example.
- the memory bit A is programmed, concurrently with voltages of the control gate CG 0 , the word line WL and the control gate CG 1 at 8.6 V, 1.5 V and 5V, respectively.
- the memory bit A is typically verified with the voltages of the control, gate CG 0 , the word line WL and the control gate CG 1 at 0 V, 4.5 V and 5 V, respectively.
- the memory bit A is programmed at an instant t0, with the voltage of the control gate CG 0 at 8.6 V and the voltage of the word line WL at 1.5 V.
- the programming is completed at an instant t1
- it is needed to decrease the voltage on the control gate CG 0 to 0 V and increase the voltage on the word line WL to 4.5V.
- the decrease of the voltage at the control gate CG 0 to 0 V takes a period of time t f and ends at an instant t2, which lead to elongation of the programming verification time.
- the voltage on the control gate CG 0 is required to increase again to 8.6 V, with the voltage on the word line WL required to drop to 1.5 V, in order to allow the next programming cycle to start.
- the increase of the voltage on the control gate CG 0 takes a period of time t r and ends at an instant t4. This makes an additional contribution to the elongation of the needed programming time.
- the programming verification control circuit includes:
- a first decoder circuit for decoding a word line of the first memory bit
- a first drive circuit for receiving a first voltage and providing the first voltage to the word line of the first memory bit based on a decoding result of the first decoder circuit
- a second decoder circuit for decoding a first control gate of the first memory bit
- a second drive circuit for receiving a second voltage and providing the second voltage to the first control gate of the first memory bit based on a decoding result of the second decoder circuit
- a voltage equalizer for receiving the first voltage, the second voltage and a first enable signal and, in event of the first enable signal being valid, controlling the first voltage and the second voltage to be conducted.
- the programming verification control circuit in event of the first enable signal is invalid, the first memory bit performs a programming/programming verification operation.
- the first decoder circuit may include a pre-decoder circuit for the word line and a first level shifter, the first level shifter is coupled to the pre-decoder circuit for the word line and configured to receive a working voltage of the word line, and the first level shifter is configured to output a first signal and a second signal that is equal in magnitude but opposite in sign to the first signal.
- the first drive circuit may include:
- a first pMOS transistor having a gate for receiving the second signal, a source is coupled to the fast voltage and a drain is coupled to the word line of the first memory bit;
- a first nMOS transistor having a gate for receiving the second signal, a source is coupled to a low voltage and a drain is coupled to the word line of the first memory bit;
- a second nMOS transistor having a gate for receiving the first signal, a source is coupled to the first voltage and a drain is coupled to the word line of the first memory bit
- the second decoder circuit may include a pre-decoder circuit for the first control gate and a second level shifter, the second level shifter is coupled to the pre-decoder circuit for the first control gate and configured to receive a working voltage of the first control gate, and the second level shifter is confirmed to output a third signal and a fourth signal that is equal in magnitude but opposite in sign to the third signal.
- the second drive circuit may include:
- a second pMOS transistor having a gate for receiving the fourth signal, a source is coupled to the second voltage and a drain is coupled to the first control gate of the first memory bit;
- a third nMOS transistor having a gate for receiving the fourth signal, a source is coupled to the low voltage and a drain is coupled to the first control gate of the first memory bit;
- a fourth nMOS transistor having a gate for receiving the third signal, a source is coupled to the second voltage and a drain is coupled to the first control gate of the first memory bit.
- the voltage equalizer may include:
- a first equalizing level shifter for receiving the first enable signal and outputting a second enable signal, the first equalizing level shifter is coupled to the first voltage;
- a first equalizing pMOS transistor having a gate for receiving the second enable signal and a source coupled to the first voltage
- a second equalizing level shifter for receiving the first enable signal and outputting a third enable signal, the first equalizing level shifter is coupled to the second voltage;
- a second equalizing pMOS transistor having a gate for receiving the third enable signal, a source is coupled to the second voltage and a drain is coupled to a drain of the first equalizing pMOS transistor.
- the memory cell may further include a second memory bit, with the programming verification control circuit further including:
- a third drive circuit for receiving a third voltage and providing the third voltage to the second control gate of the second/memory bit based on a decoding result of the third decoder circuit.
- the third decoder circuit may include a pre-decoder circuit for the second control gate and a third level shifter, the third level shifter is coupled to the pre-decoder circuit for the second control gate and configured to receive a working voltage of the second control gate, the third level shifter is configured to output a fifth signal and a sixth signal that is equal in magnitude but opposite in sign to the fifth signal.
- the third drive circuit may include:
- a third pMOS transistor having a gate for receiving the sixth signal, a source is coupled to the third voltage and a drain is coupled to the second control gate of the second memory bit;
- a fifth nMOS transistor having a gate for receiving the sixth signal, a source is coupled to the low voltage and a drain is coupled to the second control gate of the second memory bit;
- a sixth nMOS transistor having a gate for receiving the fifth signal, a source is coupled to the third voltage and a drain is coupled to the second control gate; of the second memory bit.
- a method for controlling a programming verification control circuit as defined above.
- the method includes, in a programming cycle of the first memory bit:
- the first enable signal may be controlled to be valid, thereby the voltage equalizer controlling the first voltage and the second voltage to be conducted.
- Programming verification control circuits and method for control thereof according to the present invention are advantageous over the conventional designs in that a first voltage that is provided to a word line of a memory bit and a second voltage that is provided to a control gate of the memory bit are controlled by a voltage equalizer to be conducted in the event of a first enable signal being valid, thereby equalizing the voltages at the control gate and the word line and allowing a high voltage to drop to an intermediate level without any other voltage being introduced. This can prevent the occurrence of latch-up and accelerate discharge of the high voltage. As a result, the needed programming verification time and energy loss can be reduced.
- FIG. 1 is a schematic illustration of a memory cell of a conventional flash memory device.
- FIG. 2 schematically illustrates an array of memory cells of the conventional flash memory device.
- FIG. 3 schematically illustrates variation of voltages at conventional control gate and word line.
- FIG. 4 is a schematic illustration of a programming verification control circuit according to an embodiment of the present invention.
- FIG. 5 is a schematic diagram of a first decoder circuit according to an embodiment of the present invention.
- FIG. 6 is a schematic of a first drive circuit according to an embodiment of the present invention.
- FIG. 7 is a schematic of a second decoder circuit according to an embodiment of the present invention.
- FIG. 8 is a schematic of a second drive circuit according to an embodiment of the present invention.
- FIG. 9 is a schematic of a third decoder circuit according to an embodiment of the present invention.
- FIG. 10 is a schematic of a third drive circuit according to an embodiment of the present invention.
- FIG. 11 schematically illustrates variation of voltages at conventional, control gate and word line according to an embodiment of the present invention.
- the core concept of the present invention is to provide a programming verification control circuit for control of a programming verification sequence for a memory bit of a memory cell.
- the programming verification control circuit includes: a first decoder circuit for decoding a word line of the memory bit; a first drive circuit for receiving a first voltage and providing the first voltage to the word line of the memory bit based on a decoding result of the first decoder circuit; a second decoder circuit for decoding a control gate of the memory bit; a second drive circuit for receiving a second voltage and providing the second voltage to the control gate of the memory bit based on a decoding result of the second decoder circuit; and a voltage equalizer for receiving the first voltage, the second voltage and a first enable signal and, in the event of the first enable signal being valid performing such control that the first voltage and the second voltage are both conducted, thereby equalizing the voltages at the control gate and the word line and allowing a high voltage to drop to an intermediate level without any other voltage being introduced. This can prevent the occurrence of latch-
- FIGS. 4 to 11 describe in detail programming verification control circuits and methods for control thereof according to embodiments of the present invention.
- the circuits and methods are for controlling a programming verification sequence for a memory bit of a memory cell.
- the embodiments are described with the memory bit implemented as, for example, that shown in FIGS. 1 and 2 .
- the memory cell includes two memory bits, i.e., a memory bit A and a memory bit B. While the embodiments are described in context of the programming of the memory bit A as an example, it is to be understood by those skilled in the art that the memory bit B can be programmed and verified for the programming in the same manner as done to the memory bit A, and a detailed description thereof is therefore omitted herein.
- FIG. 4 shows a programming verification control circuit 1 , including a first decoder circuit 110 , a first drive circuit 120 , a second decoder circuit 210 , a second drive circuit 220 and a voltage equalizer 400 .
- the first decoder circuit 110 is configured to decode a word line WL of the memory bit A.
- the first drive circuit 120 is configured to receive a first voltage ZVdd 2 and provide the first voltage ZVdd 2 to the word line WL of the memory bit A based on a decoding result of the first decoder circuit 110 .
- the first voltage ZVdd 2 is applied on the word line WL, as required by a programming or programming verification operation to be perforated on the memory bit A.
- the second decoder circuit 210 is configured to decode the control gate CG 0 of the memory bit A, and the second drive circuit 220 is configured to receive a second voltage ZVdd 3 and provide the second voltage ZVdd 3 to the control gate CG 0 of the memory bit A based on a decoding result of the second decoder circuit 210 .
- the second voltage ZVdd 3 is applied on the control gate CG 0 , as also required by the programming or programming verification operation performed on the memory bit A.
- the voltage equalizer 400 is configured to receive the first voltage ZVdd 2 , the second voltage ZVdd 3 and a first enable signal EN 1 and, in the event of the first enable signal EN 1 being valid, performing such control that the first voltage ZVdd 2 and the second voltage ZVdd 3 are both conducted.
- the first decoder circuit 110 includes a pre-decoder circuit 111 for the word line and a first level shifter 112 .
- the first level shifter 112 is coupled to the pre-decoder circuit 111 and configured to receive a working voltage ZVdd_WL of the word line.
- the first level shifter 112 is configured to output a first signal Sel 1 and a signal Sel 1 b that is equal in magnitude but opposite in sign to the first signal Sel 1 .
- the pre-decoder circuit 111 for the word line may be implemented as a commonly-used decoder circuit, and the first level shifter 112 may be implemented as a commonly-used level shifter.
- the first decoder circuit 110 is not limited to the structure shown in FIG. 5 , as it may have any structure as long as it is capable of decoding the word line WL of the memory bit A, and this is also within the scope of the present invention.
- the first drive circuit 120 includes: a first pMOS transistor P 1 , a first nMOS transistor N 1 and a second nMOS transistor N 2 .
- the first pMOS transistor P 1 has a gate for receiving the signal Sel 1 b that is equal in magnitude but opposite in sign to the first signal Sel 1 , a source coupled to the first voltage ZVdd 2 and a drain coupled to the word line WL of the memory bit A.
- the first nMOS transistor N 1 has a gate for receiving the signal Sel 1 b that is equal in magnitude but opposite in sign to the first signal Sel 1 , a source coupled to a low voltage (grounded in this embodiment) and a drain coupled to the word line WL of the memory bit A.
- the second nMOS transistor N 2 has a gate for receiving the first signal Sel 1 , a source coupled to the first, voltage ZVdd 2 , a drain coupled to the word line WL of the memory bit A and a substrate that is grounded.
- the first drive circuit 120 is not limited to the structure shown in FIG.
- the second decoder circuit 210 includes a pre-decoder circuit 211 for the control gate and a second level shifter 212 .
- the second level shifter 212 is coupled, to the pre-decoder circuit 211 and configured to receive a working voltage ZVdd_CG 0 of the control gate.
- the second level shifter 212 is configured to output, a second signal Sel 2 and a signal Sel 2 b that is equal in magnitude hut opposite in sign to the second signal Sel 2 .
- the pre-decoder circuit 211 may be implemented as a commonly-used decoder circuit
- the second level shifter 212 may be implemented as a commonly-used level shifter.
- the second decoder circuit 210 is not limited to the structure shown in FIG. 7 , as it may have any structure as long as it is capable of decoding the control gate CG 0 of the memory bit A, and this is also within the scope of the present invention.
- the second drive circuit 220 includes: a second pMOS transistor P 2 , a third nMOS transistor N 3 and a fourth nMOS transistor N 4 .
- the second pMOS transistor P 2 has a gate for receiving the signal Sel 2 b that is equal in magnitude but opposite in sign to the second signal Sel 2 , a source coupled to the second voltage ZVdd 3 and a drain coupled to the control gate CG 0 of the memory bit A.
- the third nMOS transistor N 3 has a gate for receiving the signal Sel 2 b that is equal in magnitude but opposite in sign to the second signal Sel 2 , a source coupled to a low voltage (grounded in this embodiment) and a drain coupled to the control gate CG 0 of the memory bit A.
- the fourth nMOS transistor N 4 has a gate for receiving the second signal Sel 2 , a source coupled to the second voltage ZVdd 3 , a drain coupled to the control gate CG 0 of the memory bit A and a substrate that is grounded.
- the second drive circuit 220 is not limited to the structure shown in FIG.
- the voltage equalizer 400 includes: a first equalizing level shifter 410 , a first equalizing pMOS transistor P b 1 , second equalizing level shifter 420 and a second equalizing pMOS transistor P b 2 .
- the first equalizing level shifter 410 is configured to receive the first enable signal EN 1 and outputting a second enable signal EN 2 .
- the first equalizing level shifter 410 is coupled to the first voltage ZVdd 2 .
- the first equalizing pMOS transistor P b 1 has a gate for receiving the second enable signal EN 2 and a source coupled to the first voltage ZVdd 2 .
- the second equalizing level shifter 420 is configured to receive the first enable signal EN 1 and output a thud enable signal EN 3 . Additionally, the second equalizing level shifter 420 is coupled to the second voltage ZVdd 3 .
- the second equalizing pMOS transistor P b 2 has a gate for receiving the third enable signal EN 3 , a source coupled to the second voltage ZVdd 3 and a drain coupled to a drain of the first equalizing pMOS transistor P b 1 .
- the voltage equalizer 400 shown in FIG. 4 can perform such control that the first voltage ZVdd 2 and the second voltage ZVdd 3 are conducted when the first enable signal EN 1 is valid.
- the voltage equalizer 400 is not limited to the structure shown in FIG.
- the programming verification control circuit 1 further includes a third decoder circuit 310 and a third drive circuit 320 .
- the third decoder circuit 310 is configured to decode a control gate CG 1 of the memory bits B
- the third drive circuit 320 is configured to receive a third voltage ZVdd 4 and provide the third voltage ZVdd 4 to a control gate CG 1 of the memory bits B based on a decoding result of the third decoder circuit 310 .
- the third decoder circuit 310 includes a pre-decoder circuit 311 for the control gate and a third level shifter 312 .
- the third level shifter 312 is coupled to the pre-decoder circuit 311 and configured to receive a working voltage ZVdd_CG 1 of the control gate.
- the third level shifter 312 is configured to output a third signal Sel 3 and a signal Sel 3 b that is equal in magnitude, but opposite in sign, to the third signal Sel 3 .
- the pre-decoder circuit 311 may be implemented as a commonly-used decoder circuit
- the third level shifter 312 may be implemented as a commonly-used level shifter.
- the third decoder circuit 310 is not limited to the structure shown in FIG. 9 , as it may have any structure as long as it is capable of decoding the control gate CG 1 of the memory bit B, and this is also within the scope of the present invention.
- the third drive circuit 320 includes: a third pMOS transistor P 3 , a fifth nMOS transistor N 5 and a sixth nMOS transistor N 6 .
- the third pMOS transistor P 3 has a gate for receiving the signal Sel 3 b that is equal in magnitude but opposite in sign to the third signal Sel 3 , a source coupled to the third voltage ZVdd 4 and a drain coupled to the control gate CG 1 of the memory bit B.
- the fifth nMOS transistor N 5 has a gate for receiving the signal Sel 3 b that is equal in magnitude but opposite in sign to the third signal Sel 3 , a source coupled to a low voltage (grounded in tins embodiment) and a drain coupled to the control gate CG 1 of the memory bit B.
- the sixth nMOS transistor N 6 has a gate for receiving the third signal Sel 3 , a source coupled to the third voltage ZVdd 4 , a drain coupled to the control gate CG 1 of the memory bit B and a substrate that is grounded.
- the third drive circuit 320 is not limited to the structure shown in FIG.
- the programming of the memory bit A may be accomplished in many programming cycles. In each of the programming cycles, the memory bit A may be programmed first, followed by the programming verification. Upon the completion of the programming verification, the programming cycle ends, followed by the start of the next programming cycle again for programming of the memory bit A and the programming verification, and so forth.
- a step S3 is carried out first to program the memory bit A at an instant T0′, concurrently with the working voltage ZVdd_CG 0 of the control gate CG 0 and the working voltage ZVdd_CG 1 of the other control gate CG 1 both in the range of 6-10 V such as, for example, 8.6 V, the second voltage ZVdd 3 also in the range of 6-10 V such as, for example, 8.6 V, the first voltage ZVdd 2 in the range of 1-2 V such as, for example, 1.5 V, and the third voltage ZVdd 4 in the range of 3-7 V such as, for example, 5 V.
- 6-10 V such as, for example, 8.6 V
- the second voltage ZVdd 3 also in the range of 6-10 V such as, for example, 8.6 V
- the first voltage ZVdd 2 in the range of 1-2 V such as, for example, 1.5 V
- the third voltage ZVdd 4 in the range of 3-7 V such as, for example, 5 V.
- the voltage at the word line WL of the memory bit A is 1.5 V, with the voltage at the control gate CG 0 of the memory bit A at 8.6 V and the voltage at the control gate CG 1 of the memory bit B at 4.5 V.
- the first enable signal EN 1 is then so controlled as to be invalid (e.g., having a voltage level of 0 V), and the first equalizing level shifter 410 and the second equalizing level shifter 420 control the second enable signal EN 2 and the third enable signal EN 3 to be valid (e.g., having a voltage level of Vdd 2 ) respectively.
- the source and drain of each of the first equalizing pMOS transistor P b 1 and the second equalizing pMOS transistor P b 2 are not conducted. Therefore, neither of the first voltage ZVdd 2 and the second voltage ZVdd 3 is conducted.
- a step S2 is then performed to end the programming of the memory bit A at an instant T1′.
- the first enable signal EN 1 is then controlled to be valid (e.g., having a voltage level of Vdd 1 ), and the first equalizing level shifter 410 and the second equalizing level shifter 420 respectively control the second enable signal EN 2 and the third enable signal EN 3 to be invalid (e.g., having a voltage level of 0 V).
- the source and drain of each of the first equalizing pMOS transistor P b 1 and the second equalizing pMOS transistor P b 2 are conducted, and the first voltage ZVdd 2 and the second voltage ZVdd 3 are both conducted and mutually equalized (i.e., the first voltage ZVdd 2 and the second voltage ZVdd 3 are averaged). Therefore, the first voltage ZVdd 2 and the second voltage ZVdd 3 both become (8.6 V+1.5 V)/2 ⁇ 5 V. Accordingly, the voltage at the word line WL of the memory bit A becomes 5 V, and the voltage at the control gate CG 0 of the memory bit A becomes 5 V too.
- a step S3 is performed to verity the programming of the memory bit A at an instant T2′, concurrent with the working voltage ZVdd_CG 0 of the control gate and the working voltage ZVdd_CG 1 of the other control gate both in the range of 6-10 V such as, for example, 8.6 V, the second voltage ZVdd 3 at 0 V, the first voltage ZVdd 2 in the range of 3-7 V such as, for example, 4.5 V, and the third voltage ZVdd 4 also in the range of 3-7 V such as, for example, 5 V.
- the first enable signal EN 1 is then controlled to be invalid (e.g., having a voltage level of 0 V), and the first equalizing level shifter 410 and the second equalizing level shifter 420 respectively control the second enable signal EN 2 and the third enable signal EN 3 to be valid (e.g., having a voltage level of Vdd 2 ).
- the source and drain of each of the first equalizing pMOS transistor P b 1 and the second equalizing pMOS transistor P b 2 are not conducted. Therefore, neither of the first voltage ZVdd 2 and the second voltage ZVdd 3 is conducted. As such, as shown in FIG.
- the voltage at the word line WL of the memory bit A decreases from 5 V to 4.5 V, with the voltage at the control gate CG 0 of the memory bit A decreasing from 5 V to 0 V and with the voltage at the control gate CG 1 of the memory bit B at 4.5 V.
- the discharge of the voltage at the word line WL of the memory bit A from 5 V to 4.5 V is rapid and not associated with the occurrence of latch-up.
- the discharge of the voltage at the control gate CG 0 of the memory bit A from 5 V to 0 V is also rapid and not associated with the occurrence of latch-up.
- the programming verification ends at an instant T4′, and at the same time, there begins the next programming cycle.
- the first enable signal EN 1 is controlled to be valid, thereby allowing the voltage equalizer 400 to control the first voltage and the second voltage to he conducted.
- the first enable signal EN 1 is controlled to be valid (e.g., having a voltage level of Vdd 1 ), and the first equalizing level shifter 410 and the second equalizing level shifter 420 thereby respectively control the second enable signal EN 2 and the third enable signal EN 3 to be invalid (e.g., having a voltage level of 0 V).
- the source and drain of each of the first equalizing pMOS transistor P b 1 and the second equalizing pMOS transistor P b 2 are conducted, and the first voltage ZVdd 2 and the second voltage ZVdd 3 are both conducted and mutually equalized (i.e., the first voltage ZVdd 2 and the second voltage ZVdd 3 are averaged).
- the first voltage ZVdd 2 and the second voltage ZVdd 3 both become (4.5 V+0 V)/2 ⁇ 2.25 V. Accordingly, the voltage at the word line WL of the memory bit A becomes 2.25 V, and the voltage at the control gate CG 0 of the memory bit A becomes 2.25 V too. During this process, the change of the voltage at the word line WL of the memory bit A from 4.5 V to 2.25 V is rapid, and the change of the voltage at the control gate CG 0 of the memory bit A from 0 V to 2.25 V is also rapid.
- the memory bit A is programmed, concurrently with the working voltage ZVdd_CG 0 of the control gate and the working voltage ZVdd_CG 1 of the other control gate both in the range of 6-10 V such as, for example, 8.6 V, the second voltage ZVdd 3 also in the range of 6-10 V such as, for example, 8.6 V, the first voltage ZVdd 2 in the range of 1-2 V such as for example, 1.5 V, and the third voltage ZVdd 4 in the range of 3-7 V such as, for example, 5 V.
- the first enable signal EN 1 is then controlled to be invalid (e.g., having a voltage level of 0 V), and the first equalizing level shifter 410 and the second equalizing level shifter 420 thereby respectively control the second enable signal EN 2 and the third enable signal EN 3 to be valid (e.g., having a voltage level of Vdd 2 ).
- the source and drain of each of the first equalizing pMOS transistor P b 1 and the second equalizing pMOS transistor P b 2 are not conducted. Therefore, neither of the first voltage ZVdd 2 and the second voltage ZVdd 3 is conducted. As such, as shown in FIG.
- the voltage at the word line WL of the memory bit A decreases from 2.25 V to 1.5 V, with the voltage at the control gate CG 0 of the memory bit A rising from 2.25 V to 8.6 V and with the voltage at the control gate CG 1 of the memory bit B at 4.5 V.
- the involvement of latch-up and other effects is avoided, and the decrease of the voltage at the word line WL of the memory bit A from 2.25 V to 1.5 V is rapid and only takes a very short period of time T r .
- the change of the voltage at the control gate CG 0 of the memory bit A from 2.25 V to 8.6 V is also rapid. This is conducive to the acceleration of the overall programming process of the memory bit A.
Abstract
Description
- This application claims the priority of Chinese patent application number 201510309118.7, filed on Jun. 7, 2015, the entire contents of which are incorporated herein by reference.
- The present invention relates to verification of programming of a memory device and, in particular, to programming verification control circuits and methods for control thereof.
- As a kind of integrated circuit (IC) memory devices, flash memories have the function of storing information in an electrically erasable and rewritable manner. For this reason, flash memories are widely used in electronic products including portable computers, cell phones and digital music players. A flash memory has many memory cells that are required to be so arranged as to be adapted to its operations. Each of the memory cells stores a single bit of data.
-
FIG. 1 schematically illustrates a memory cell of a conventional flash memory device, andFIG. 2 shows an array of memory cells of the conventional device. The flash memory device includes a plurality of the arrayed memory cells, as well as a plurality of bit lines (BL0, BL1, BL2, BL.3, . . , , and BLm), a plurality of word lines (WL) and a plurality of control gates (e.g., CG0, CB1 and so forth), configured to select and provide drive signals to the individual memory cells. As shown inFIG. 1 , each of the memory cells includes two memory bits, i.e., bits A and B, and a word line common to the two bits. Each of the memory bits includes a bit line and a control gate. While only two control gates are depicted inFIG. 2 , i.e., CG0 and CG1, in practical, the memory may have more control gates (i.e., CG0, CG1, CG2, CG3, . . . , and CGn), as generally and commonly known in this art, and a detailed description thereof is therefore omitted herein. - Conventionally, in order to check whether a memory bit has been properly programmed, programming verification is generally carried out by reading the memory bit. This process is explained below with the programming of the memory bit A as an example. Typically, the memory bit A is programmed, concurrently with voltages of the control gate CG0, the word line WL and the control gate CG1 at 8.6 V, 1.5 V and 5V, respectively. In addition, after completion of the programming, the memory bit A is typically verified with the voltages of the control, gate CG0, the word line WL and the control gate CG1 at 0 V, 4.5 V and 5 V, respectively.
- Referring to
FIG. 3 , in which the abscissa axis represents time t. The memory bit A is programmed at an instant t0, with the voltage of the control gate CG0 at 8.6 V and the voltage of the word line WL at 1.5 V. After the programming is completed at an instant t1, in order to enable the programming verification, it is needed to decrease the voltage on the control gate CG0 to 0 V and increase the voltage on the word line WL to 4.5V. However, due to latch-up and other effects, the decrease of the voltage at the control gate CG0 to 0 V takes a period of time tf and ends at an instant t2, which lead to elongation of the programming verification time. In addition, after the programming verification has ended at an instant t3, the voltage on the control gate CG0 is required to increase again to 8.6 V, with the voltage on the word line WL required to drop to 1.5 V, in order to allow the next programming cycle to start. Again, due to latch-up and other effects, the increase of the voltage on the control gate CG0 takes a period of time tr and ends at an instant t4. This makes an additional contribution to the elongation of the needed programming time. - It is therefore an objective of the present invention to provide a programming verification circuit and a method for control thereof, which can effectively reduce programming unification time and facilitate energy loss reduction.
- In pursuit of this objective, the present invention provides a programming verification control circuit for controlling a programming verification sequence for a first memory bit of a memory cell. The programming verification control circuit includes:
- a first decoder circuit for decoding a word line of the first memory bit;
- a first drive circuit, for receiving a first voltage and providing the first voltage to the word line of the first memory bit based on a decoding result of the first decoder circuit;
- a second decoder circuit for decoding a first control gate of the first memory bit;
- a second drive circuit for receiving a second voltage and providing the second voltage to the first control gate of the first memory bit based on a decoding result of the second decoder circuit; and
- a voltage equalizer for receiving the first voltage, the second voltage and a first enable signal and, in event of the first enable signal being valid, controlling the first voltage and the second voltage to be conducted.
- Further, in the programming verification control circuit, in event of the first enable signal is invalid, the first memory bit performs a programming/programming verification operation.
- Further, in the programming verification control circuit, the first decoder circuit may include a pre-decoder circuit for the word line and a first level shifter, the first level shifter is coupled to the pre-decoder circuit for the word line and configured to receive a working voltage of the word line, and the first level shifter is configured to output a first signal and a second signal that is equal in magnitude but opposite in sign to the first signal.
- Further, in the programming verification control circuit, the first drive circuit may include:
- a first pMOS transistor, having a gate for receiving the second signal, a source is coupled to the fast voltage and a drain is coupled to the word line of the first memory bit;
- a first nMOS transistor, having a gate for receiving the second signal, a source is coupled to a low voltage and a drain is coupled to the word line of the first memory bit; and
- a second nMOS transistor, having a gate for receiving the first signal, a source is coupled to the first voltage and a drain is coupled to the word line of the first memory bit
- Further, in the programming verification control circuit, the second decoder circuit may include a pre-decoder circuit for the first control gate and a second level shifter, the second level shifter is coupled to the pre-decoder circuit for the first control gate and configured to receive a working voltage of the first control gate, and the second level shifter is confirmed to output a third signal and a fourth signal that is equal in magnitude but opposite in sign to the third signal.
- Further, in the programming verification control circuit, the second drive circuit may include:
- a second pMOS transistor, having a gate for receiving the fourth signal, a source is coupled to the second voltage and a drain is coupled to the first control gate of the first memory bit;
- a third nMOS transistor, having a gate for receiving the fourth signal, a source is coupled to the low voltage and a drain is coupled to the first control gate of the first memory bit; and
- a fourth nMOS transistor, having a gate for receiving the third signal, a source is coupled to the second voltage and a drain is coupled to the first control gate of the first memory bit.
- Further, in the programming verification control circuit, the voltage equalizer may include:
- a first equalizing level shifter for receiving the first enable signal and outputting a second enable signal, the first equalizing level shifter is coupled to the first voltage;
- a first equalizing pMOS transistor, having a gate for receiving the second enable signal and a source coupled to the first voltage;
- a second equalizing level shifter for receiving the first enable signal and outputting a third enable signal, the first equalizing level shifter is coupled to the second voltage; and
- a second equalizing pMOS transistor, having a gate for receiving the third enable signal, a source is coupled to the second voltage and a drain is coupled to a drain of the first equalizing pMOS transistor.
- Further, in the programming verification control circuit, the memory cell may further include a second memory bit, with the programming verification control circuit further including:
- a third decoder circuit for decoding a second control gate of the second memory bit; and
- a third drive circuit for receiving a third voltage and providing the third voltage to the second control gate of the second/memory bit based on a decoding result of the third decoder circuit.
- Further, in the programming verification control circuit, the third decoder circuit may include a pre-decoder circuit for the second control gate and a third level shifter, the third level shifter is coupled to the pre-decoder circuit for the second control gate and configured to receive a working voltage of the second control gate, the third level shifter is configured to output a fifth signal and a sixth signal that is equal in magnitude but opposite in sign to the fifth signal.
- Further, in the programming verification control circuit, the third drive circuit may include:
- a third pMOS transistor, having a gate for receiving the sixth signal, a source is coupled to the third voltage and a drain is coupled to the second control gate of the second memory bit;
- a fifth nMOS transistor, having a gate for receiving the sixth signal, a source is coupled to the low voltage and a drain is coupled to the second control gate of the second memory bit; and
- a sixth nMOS transistor, having a gate for receiving the fifth signal, a source is coupled to the third voltage and a drain is coupled to the second control gate; of the second memory bit.
- According to a second aspect of the present invention, there is also provided a method for controlling a programming verification control circuit as defined above. The method includes, in a programming cycle of the first memory bit:
- controlling the first enable signal to be invalid, thereby performing a programming operation on the first memory bit;
- controlling the first enable signal to be valid, thereby the voltage equalizer controlling the first voltage and the second voltage to be conducted; and
- controlling the first enable signal to be invalid, thereby performing a programming verification operation on the first memory bit.
- Further, in the method, between different programming cycles of the first memory bit, the first enable signal may be controlled to be valid, thereby the voltage equalizer controlling the first voltage and the second voltage to be conducted.
- Programming verification control circuits and method for control thereof according to the present invention are advantageous over the conventional designs in that a first voltage that is provided to a word line of a memory bit and a second voltage that is provided to a control gate of the memory bit are controlled by a voltage equalizer to be conducted in the event of a first enable signal being valid, thereby equalizing the voltages at the control gate and the word line and allowing a high voltage to drop to an intermediate level without any other voltage being introduced. This can prevent the occurrence of latch-up and accelerate discharge of the high voltage. As a result, the needed programming verification time and energy loss can be reduced.
-
FIG. 1 is a schematic illustration of a memory cell of a conventional flash memory device. -
FIG. 2 schematically illustrates an array of memory cells of the conventional flash memory device. -
FIG. 3 schematically illustrates variation of voltages at conventional control gate and word line. -
FIG. 4 is a schematic illustration of a programming verification control circuit according to an embodiment of the present invention. -
FIG. 5 is a schematic diagram of a first decoder circuit according to an embodiment of the present invention. -
FIG. 6 is a schematic of a first drive circuit according to an embodiment of the present invention. -
FIG. 7 is a schematic of a second decoder circuit according to an embodiment of the present invention. -
FIG. 8 is a schematic of a second drive circuit according to an embodiment of the present invention. -
FIG. 9 is a schematic of a third decoder circuit according to an embodiment of the present invention. -
FIG. 10 is a schematic of a third drive circuit according to an embodiment of the present invention. -
FIG. 11 schematically illustrates variation of voltages at conventional, control gate and word line according to an embodiment of the present invention. - Programming verification control circuits and methods for control thereof according to the present invention will be described in greater detail in the following description which presents preferred embodiments of the invention, in conjunction with the accompanying drawing. It is to be appreciated that those of skill in the art can make changes in the invention disclosed herein while still obtaining the beneficial results thereof. Therefore, the following description shall be construed as being intended to be widely known by those skilled in the art rather than as limiting the invention.
- For simplicity and clarity of illustration, not all features of the specific embodiments are described. Additionally, descriptions and details of well-known functions and structures are omitted to avoid unnecessarily obscuring the invention. The development of any specific embodiment of the present invention includes specific decisions made to achieve the developer's specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art.
- The present invention will be further described in the following paragraphs by way of example with reference to the accompanying drawing. Features and advantages of the invention will be more apparent from the following detailed description, and from the appended claims. Note that the accompanying drawing is provided in a very simplified form not necessarily presented to scale, with the only intention of facilitating convenience and clarity in explaining a few exemplary embodiments of the invention.
- The core concept of the present invention is to provide a programming verification control circuit for control of a programming verification sequence for a memory bit of a memory cell. The programming verification control circuit includes: a first decoder circuit for decoding a word line of the memory bit; a first drive circuit for receiving a first voltage and providing the first voltage to the word line of the memory bit based on a decoding result of the first decoder circuit; a second decoder circuit for decoding a control gate of the memory bit; a second drive circuit for receiving a second voltage and providing the second voltage to the control gate of the memory bit based on a decoding result of the second decoder circuit; and a voltage equalizer for receiving the first voltage, the second voltage and a first enable signal and, in the event of the first enable signal being valid performing such control that the first voltage and the second voltage are both conducted, thereby equalizing the voltages at the control gate and the word line and allowing a high voltage to drop to an intermediate level without any other voltage being introduced. This can prevent the occurrence of latch-up and accelerate discharge of the high voltage. As a result, the needed programming verification time and energy loss can be reduced.
- Reference is made to
FIGS. 4 to 11 below to describe in detail programming verification control circuits and methods for control thereof according to embodiments of the present invention. The circuits and methods are for controlling a programming verification sequence for a memory bit of a memory cell. The embodiments are described with the memory bit implemented as, for example, that shown inFIGS. 1 and 2 . The memory cell includes two memory bits, i.e., a memory bit A and a memory bit B. While the embodiments are described in context of the programming of the memory bit A as an example, it is to be understood by those skilled in the art that the memory bit B can be programmed and verified for the programming in the same manner as done to the memory bit A, and a detailed description thereof is therefore omitted herein. -
FIG. 4 shows a programmingverification control circuit 1, including afirst decoder circuit 110, afirst drive circuit 120, asecond decoder circuit 210, asecond drive circuit 220 and avoltage equalizer 400. Thefirst decoder circuit 110 is configured to decode a word line WL of the memory bit A. Thefirst drive circuit 120 is configured to receive a first voltage ZVdd2 and provide the first voltage ZVdd2 to the word line WL of the memory bit A based on a decoding result of thefirst decoder circuit 110. The first voltage ZVdd2 is applied on the word line WL, as required by a programming or programming verification operation to be perforated on the memory bit A. Thesecond decoder circuit 210 is configured to decode the control gate CG0 of the memory bit A, and thesecond drive circuit 220 is configured to receive a second voltage ZVdd3 and provide the second voltage ZVdd3 to the control gate CG0 of the memory bit A based on a decoding result of thesecond decoder circuit 210. The second voltage ZVdd3 is applied on the control gate CG0, as also required by the programming or programming verification operation performed on the memory bit A. Thevoltage equalizer 400 is configured to receive the first voltage ZVdd2, the second voltage ZVdd3 and a first enable signal EN1 and, in the event of the first enable signal EN1 being valid, performing such control that the first voltage ZVdd2 and the second voltage ZVdd3 are both conducted. - Preferably, as shown in
FIG. 5 , thefirst decoder circuit 110 includes apre-decoder circuit 111 for the word line and afirst level shifter 112. Additionally, thefirst level shifter 112 is coupled to thepre-decoder circuit 111 and configured to receive a working voltage ZVdd_WL of the word line. Moreover, thefirst level shifter 112 is configured to output a first signal Sel1 and a signal Sel1 b that is equal in magnitude but opposite in sign to the first signal Sel1. Thepre-decoder circuit 111 for the word line may be implemented as a commonly-used decoder circuit, and thefirst level shifter 112 may be implemented as a commonly-used level shifter. Circuit structures of thepre-decoder circuit 111 and thefirst level shifter 112 are understandable by those of ordinary skill in the art, and a detailed description thereof is therefore omitted herein. Thefirst decoder circuit 110 is not limited to the structure shown inFIG. 5 , as it may have any structure as long as it is capable of decoding the word line WL of the memory bit A, and this is also within the scope of the present invention. - In one embodiment, as shown in
FIG. 6 , thefirst drive circuit 120 includes: a first pMOS transistor P1, a first nMOS transistor N1 and a second nMOS transistor N2. The first pMOS transistor P1 has a gate for receiving the signal Sel1 b that is equal in magnitude but opposite in sign to the first signal Sel1, a source coupled to the first voltage ZVdd2 and a drain coupled to the word line WL of the memory bit A. The first nMOS transistor N1 has a gate for receiving the signal Sel1 b that is equal in magnitude but opposite in sign to the first signal Sel1, a source coupled to a low voltage (grounded in this embodiment) and a drain coupled to the word line WL of the memory bit A. The second nMOS transistor N2 has a gate for receiving the first signal Sel1, a source coupled to the first, voltage ZVdd2, a drain coupled to the word line WL of the memory bit A and a substrate that is grounded. Thefirst drive circuit 120 is not limited to the structure shown inFIG. 6 , as it may have any structure as long as it is capable of providing the first voltage ZVdd2 to the word line WL of the memory bit A based on the decoding result of thefirst decoder circuit 110, and this is also within the scope of the present invention. - Preferably, as shown in
FIG. 7 , thesecond decoder circuit 210 includes apre-decoder circuit 211 for the control gate and asecond level shifter 212. Additionally, thesecond level shifter 212 is coupled, to thepre-decoder circuit 211 and configured to receive a working voltage ZVdd_CG0 of the control gate. Moreover, thesecond level shifter 212 is configured to output, a second signal Sel2 and a signal Sel2 b that is equal in magnitude hut opposite in sign to the second signal Sel2. Thepre-decoder circuit 211 may be implemented as a commonly-used decoder circuit, and thesecond level shifter 212 may be implemented as a commonly-used level shifter. Circuit structures of thepre-decoder circuit 211 and thesecond level shifter 212 are understandable by those of ordinary skill in the art, and a detailed description thereof is therefore omitted herein. Thesecond decoder circuit 210 is not limited to the structure shown inFIG. 7 , as it may have any structure as long as it is capable of decoding the control gate CG0 of the memory bit A, and this is also within the scope of the present invention. - In one embodiment, as shown to
FIG. 8 , thesecond drive circuit 220 includes: a second pMOS transistor P2, a third nMOS transistor N3 and a fourth nMOS transistor N4. The second pMOS transistor P2 has a gate for receiving the signal Sel2 b that is equal in magnitude but opposite in sign to the second signal Sel2, a source coupled to the second voltage ZVdd3 and a drain coupled to the control gate CG0 of the memory bit A. The third nMOS transistor N3 has a gate for receiving the signal Sel2 b that is equal in magnitude but opposite in sign to the second signal Sel2, a source coupled to a low voltage (grounded in this embodiment) and a drain coupled to the control gate CG0 of the memory bit A. The fourth nMOS transistor N4 has a gate for receiving the second signal Sel2, a source coupled to the second voltage ZVdd3, a drain coupled to the control gate CG0 of the memory bit A and a substrate that is grounded. Thesecond drive circuit 220 is not limited to the structure shown inFIG. 8 , as it may have any structure as long as it is capable of providing the second voltage ZVdd3 to the control gate CG0 of the memory bit A based on the decoding result of thesecond decoder circuit 210, and this is also within the scope of the present invention. - Preferably, as shown in
FIG. 4 , thevoltage equalizer 400 includes: a firstequalizing level shifter 410, a first equalizingpMOS transistor P b 1, secondequalizing level shifter 420 and a second equalizingpMOS transistor P b 2. The firstequalizing level shifter 410 is configured to receive the first enable signal EN1 and outputting a second enable signal EN2. Additionally, the firstequalizing level shifter 410 is coupled to the first voltage ZVdd2. The first equalizingpMOS transistor P b 1 has a gate for receiving the second enable signal EN2 and a source coupled to the first voltage ZVdd2. The secondequalizing level shifter 420 is configured to receive the first enable signal EN1 and output a thud enable signal EN3. Additionally, the secondequalizing level shifter 420 is coupled to the second voltage ZVdd3. The second equalizingpMOS transistor P b 2 has a gate for receiving the third enable signal EN3, a source coupled to the second voltage ZVdd3 and a drain coupled to a drain of the first equalizingpMOS transistor P b 1. Thevoltage equalizer 400 shown inFIG. 4 can perform such control that the first voltage ZVdd2 and the second voltage ZVdd3 are conducted when the first enable signal EN1 is valid. Thevoltage equalizer 400 is not limited to the structure shown inFIG. 4 , as it may have any structure as long as it is capable of perform such control that the first voltage ZVdd2 and the second voltage ZVdd3 are both conducted in case of the first enable signal EN1 being valid, and this is also within the scope of the present invention. - Preferably, as shown in
FIG. 4 , the programmingverification control circuit 1 further includes athird decoder circuit 310 and athird drive circuit 320. Thethird decoder circuit 310 is configured to decode a control gate CG1 of the memory bits B, and thethird drive circuit 320 is configured to receive a third voltage ZVdd4 and provide the third voltage ZVdd4 to a control gate CG1 of the memory bits B based on a decoding result of thethird decoder circuit 310. - In one embodiment, as shown in
FIG. 9 , thethird decoder circuit 310 includes apre-decoder circuit 311 for the control gate and athird level shifter 312. Thethird level shifter 312 is coupled to thepre-decoder circuit 311 and configured to receive a working voltage ZVdd_CG1 of the control gate. Moreover, thethird level shifter 312 is configured to output a third signal Sel3 and a signal Sel3 b that is equal in magnitude, but opposite in sign, to the third signal Sel3. Thepre-decoder circuit 311 may be implemented as a commonly-used decoder circuit, and thethird level shifter 312 may be implemented as a commonly-used level shifter. Circuit structures of thepre-decoder circuit 311 and thethird level shifter 312 are understandable by those of ordinary skill in the art, and a detailed description thereof is therefore omitted herein. Thethird decoder circuit 310 is not limited to the structure shown inFIG. 9 , as it may have any structure as long as it is capable of decoding the control gate CG1 of the memory bit B, and this is also within the scope of the present invention. - In one embodiment, as shown in
FIG. 10 , thethird drive circuit 320 includes: a third pMOS transistor P3, a fifth nMOS transistor N5 and a sixth nMOS transistor N6. The third pMOS transistor P3 has a gate for receiving the signal Sel3 b that is equal in magnitude but opposite in sign to the third signal Sel3, a source coupled to the third voltage ZVdd4 and a drain coupled to the control gate CG1 of the memory bit B. The fifth nMOS transistor N5 has a gate for receiving the signal Sel3 b that is equal in magnitude but opposite in sign to the third signal Sel3, a source coupled to a low voltage (grounded in tins embodiment) and a drain coupled to the control gate CG1 of the memory bit B. The sixth nMOS transistor N6 has a gate for receiving the third signal Sel3, a source coupled to the third voltage ZVdd4, a drain coupled to the control gate CG1 of the memory bit B and a substrate that is grounded. Thethird drive circuit 320 is not limited to the structure shown inFIG. 10 , as it may have any structure as long as it is capable of providing the third voltage ZVdd4 to the control gate CG1 of the memory bit B based on the decoding result of thethird decoder circuit 310, and this is also within the scope of the present invention. - In general terms, the programming of the memory bit A may be accomplished in many programming cycles. In each of the programming cycles, the memory bit A may be programmed first, followed by the programming verification. Upon the completion of the programming verification, the programming cycle ends, followed by the start of the next programming cycle again for programming of the memory bit A and the programming verification, and so forth.
- During programming verification control of the programming
verification control circuit 1 over the memory bit A, in any one of the programming cycle for the memory bit A: - a step S3 is carried out first to program the memory bit A at an instant T0′, concurrently with the working voltage ZVdd_CG0 of the control gate CG0 and the working voltage ZVdd_CG1 of the other control gate CG1 both in the range of 6-10 V such as, for example, 8.6 V, the second voltage ZVdd3 also in the range of 6-10 V such as, for example, 8.6 V, the first voltage ZVdd2 in the range of 1-2 V such as, for example, 1.5 V, and the third voltage ZVdd4 in the range of 3-7 V such as, for example, 5 V. As such, as shown in
FIG. 11 , the voltage at the word line WL of the memory bit A is 1.5 V, with the voltage at the control gate CG0 of the memory bit A at 8.6 V and the voltage at the control gate CG1 of the memory bit B at 4.5 V. The first enable signal EN1 is then so controlled as to be invalid (e.g., having a voltage level of 0 V), and the firstequalizing level shifter 410 and the secondequalizing level shifter 420 control the second enable signal EN2 and the third enable signal EN3 to be valid (e.g., having a voltage level of Vdd2) respectively. As a result, the source and drain of each of the first equalizingpMOS transistor P b 1 and the second equalizingpMOS transistor P b 2 are not conducted. Therefore, neither of the first voltage ZVdd2 and the second voltage ZVdd3 is conducted. - A step S2 is then performed to end the programming of the memory bit A at an instant T1′. The first enable signal EN1 is then controlled to be valid (e.g., having a voltage level of Vdd1), and the first
equalizing level shifter 410 and the secondequalizing level shifter 420 respectively control the second enable signal EN2 and the third enable signal EN3 to be invalid (e.g., having a voltage level of 0 V). As a result, the source and drain of each of the first equalizingpMOS transistor P b 1 and the second equalizingpMOS transistor P b 2 are conducted, and the first voltage ZVdd2 and the second voltage ZVdd3 are both conducted and mutually equalized (i.e., the first voltage ZVdd2 and the second voltage ZVdd3 are averaged). Therefore, the first voltage ZVdd2 and the second voltage ZVdd3 both become (8.6 V+1.5 V)/2≈5 V. Accordingly, the voltage at the word line WL of the memory bit A becomes 5 V, and the voltage at the control gate CG0 of the memory bit A becomes 5 V too. During this process, the change of the voltage at the word line WL of the memory bit A from 1.5 V to 5 V is rapid, and the discharge of the voltage at the control gate CG0 of the memory bit A from 8.6 V to 5 V is also rapid and not associated with the occurrence of latch-up. - Thereafter, a step S3 is performed to verity the programming of the memory bit A at an instant T2′, concurrent with the working voltage ZVdd_CG0 of the control gate and the working voltage ZVdd_CG1 of the other control gate both in the range of 6-10 V such as, for example, 8.6 V, the second voltage ZVdd3 at 0 V, the first voltage ZVdd2 in the range of 3-7 V such as, for example, 4.5 V, and the third voltage ZVdd4 also in the range of 3-7 V such as, for example, 5 V. The first enable signal EN1 is then controlled to be invalid (e.g., having a voltage level of 0 V), and the first
equalizing level shifter 410 and the secondequalizing level shifter 420 respectively control the second enable signal EN2 and the third enable signal EN3 to be valid (e.g., having a voltage level of Vdd2). As a result, the source and drain of each of the first equalizingpMOS transistor P b 1 and the second equalizingpMOS transistor P b 2 are not conducted. Therefore, neither of the first voltage ZVdd2 and the second voltage ZVdd3 is conducted. As such, as shown inFIG. 11 , at an instant T3′, the voltage at the word line WL of the memory bit A decreases from 5 V to 4.5 V, with the voltage at the control gate CG0 of the memory bit A decreasing from 5 V to 0 V and with the voltage at the control gate CG1 of the memory bit B at 4.5 V. The discharge of the voltage at the word line WL of the memory bit A from 5 V to 4.5 V is rapid and not associated with the occurrence of latch-up. Similarly, the discharge of the voltage at the control gate CG0 of the memory bit A from 5 V to 0 V is also rapid and not associated with the occurrence of latch-up. - According to this embodiment, the involvement of latch-up and other effects is avoided, and the decrease of the voltage at the control gate CG0 of the memory bit A to 0 V at the instant T3′ only takes a very short period of time Tf. This leads to a great reduction in the needed programming verification time.
- The programming verification ends at an instant T4′, and at the same time, there begins the next programming cycle. Preferably, between different programming cycles of the memory bit A, the first enable signal EN1 is controlled to be valid, thereby allowing the
voltage equalizer 400 to control the first voltage and the second voltage to he conducted. - Specifically, at the instant T4′. the first enable signal EN1 is controlled to be valid (e.g., having a voltage level of Vdd1), and the first
equalizing level shifter 410 and the secondequalizing level shifter 420 thereby respectively control the second enable signal EN2 and the third enable signal EN3 to be invalid (e.g., having a voltage level of 0 V). As a result, the source and drain of each of the first equalizingpMOS transistor P b 1 and the second equalizingpMOS transistor P b 2 are conducted, and the first voltage ZVdd2 and the second voltage ZVdd3 are both conducted and mutually equalized (i.e., the first voltage ZVdd2 and the second voltage ZVdd3 are averaged). Therefore, the first voltage ZVdd2 and the second voltage ZVdd3 both become (4.5 V+0 V)/2≈2.25 V. Accordingly, the voltage at the word line WL of the memory bit A becomes 2.25 V, and the voltage at the control gate CG0 of the memory bit A becomes 2.25 V too. During this process, the change of the voltage at the word line WL of the memory bit A from 4.5 V to 2.25 V is rapid, and the change of the voltage at the control gate CG0 of the memory bit A from 0 V to 2.25 V is also rapid. - At an instant T5′, the memory bit A is programmed, concurrently with the working voltage ZVdd_CG0 of the control gate and the working voltage ZVdd_CG1 of the other control gate both in the range of 6-10 V such as, for example, 8.6 V, the second voltage ZVdd3 also in the range of 6-10 V such as, for example, 8.6 V, the first voltage ZVdd2 in the range of 1-2 V such as for example, 1.5 V, and the third voltage ZVdd4 in the range of 3-7 V such as, for example, 5 V. The first enable signal EN1 is then controlled to be invalid (e.g., having a voltage level of 0 V), and the first
equalizing level shifter 410 and the secondequalizing level shifter 420 thereby respectively control the second enable signal EN2 and the third enable signal EN3 to be valid (e.g., having a voltage level of Vdd2). As a result, the source and drain of each of the first equalizingpMOS transistor P b 1 and the second equalizingpMOS transistor P b 2 are not conducted. Therefore, neither of the first voltage ZVdd2 and the second voltage ZVdd3 is conducted. As such, as shown inFIG. 11 , at an instant T6′, the voltage at the word line WL of the memory bit A decreases from 2.25 V to 1.5 V, with the voltage at the control gate CG0 of the memory bit A rising from 2.25 V to 8.6 V and with the voltage at the control gate CG1 of the memory bit B at 4.5 V. - According to this embodiment, the involvement of latch-up and other effects is avoided, and the decrease of the voltage at the word line WL of the memory bit A from 2.25 V to 1.5 V is rapid and only takes a very short period of time Tr. At the same time, the change of the voltage at the control gate CG0 of the memory bit A from 2.25 V to 8.6 V is also rapid. This is conducive to the acceleration of the overall programming process of the memory bit A.
- Obviously, those skilled in the art may make various modifications and alterations without departing from the spirit and scope of the invention. It is therefore intended that the invention be construed as including all such modifications and alterations insofar as they fall within the scope of the appended claims or equivalents thereof.
Claims (12)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201510309118.7 | 2015-06-07 | ||
CN201510309118.7A CN104867523B (en) | 2015-06-07 | 2015-06-07 | Programming verification control circuit and control method thereof |
CN201510309118 | 2015-06-07 |
Publications (2)
Publication Number | Publication Date |
---|---|
US20160358665A1 true US20160358665A1 (en) | 2016-12-08 |
US9520202B1 US9520202B1 (en) | 2016-12-13 |
Family
ID=53913307
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/976,704 Active US9520202B1 (en) | 2015-06-07 | 2015-12-21 | Programming verification control circuit and method for control thereof |
Country Status (2)
Country | Link |
---|---|
US (1) | US9520202B1 (en) |
CN (1) | CN104867523B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10957399B2 (en) * | 2019-01-22 | 2021-03-23 | Shanghai Huahong Grace Semiconductor Manufacturing Corporation | Memory and operation method thereof |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105810247B (en) * | 2016-04-19 | 2022-11-18 | 兆易创新科技集团股份有限公司 | Word line driving circuit |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3640180B2 (en) * | 2001-07-23 | 2005-04-20 | セイコーエプソン株式会社 | Nonvolatile semiconductor memory device |
JP3738838B2 (en) * | 2002-02-13 | 2006-01-25 | セイコーエプソン株式会社 | Nonvolatile semiconductor memory device |
US7352033B2 (en) * | 2005-08-30 | 2008-04-01 | Halo Lsi Inc. | Twin MONOS array for high speed application |
CN102394108A (en) * | 2011-09-01 | 2012-03-28 | 上海宏力半导体制造有限公司 | Programming verification optimization method for flash memory |
US8971147B2 (en) * | 2012-10-30 | 2015-03-03 | Freescale Semiconductor, Inc. | Control gate word line driver circuit for multigate memory |
CN103077742B (en) * | 2012-12-21 | 2017-02-08 | 上海华虹宏力半导体制造有限公司 | Row decoding circuit and memory |
CN104681088B (en) * | 2015-02-28 | 2018-02-09 | 上海华虹宏力半导体制造有限公司 | A kind of row address decoding circuit |
-
2015
- 2015-06-07 CN CN201510309118.7A patent/CN104867523B/en active Active
- 2015-12-21 US US14/976,704 patent/US9520202B1/en active Active
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10957399B2 (en) * | 2019-01-22 | 2021-03-23 | Shanghai Huahong Grace Semiconductor Manufacturing Corporation | Memory and operation method thereof |
Also Published As
Publication number | Publication date |
---|---|
US9520202B1 (en) | 2016-12-13 |
CN104867523A (en) | 2015-08-26 |
CN104867523B (en) | 2020-06-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11955204B2 (en) | Apparatuses and methods for concurrently accessing different memory planes of a memory | |
KR101119343B1 (en) | Program method of semiconductor memory device | |
JP5667143B2 (en) | Nonvolatile semiconductor memory | |
TWI729221B (en) | Memory device and operating method thereof | |
US8174906B2 (en) | Nonvolatile memory device, program method and precharge voltage boosting method thereof, and memory system including the nonvolatile memory device | |
US8908430B2 (en) | Semiconductor device and method of operating the same | |
JP2012058860A (en) | Memory system | |
TWI715937B (en) | Semiconductor memory device | |
JP5905547B1 (en) | Semiconductor memory device | |
KR20100111532A (en) | Programming method of nonvolatile memory device | |
US9514826B2 (en) | Programming method for NAND-type flash memory | |
KR20110078752A (en) | Method of operating a semiconductor memory device | |
US20150109841A1 (en) | Semiconductor device and method for operating the same | |
US8233327B2 (en) | Method of programming nonvolatile memory device | |
US11222705B2 (en) | Memory device and operating method of the memory device | |
US10497447B2 (en) | Memory device capable of supporting multiple read operations | |
CN210136492U (en) | Electronic device | |
US8213235B2 (en) | Nonvolatile memory device | |
JP2010257540A (en) | Nonvolatile semiconductor memory apparatus | |
US9520202B1 (en) | Programming verification control circuit and method for control thereof | |
US20100232233A1 (en) | Nonvolatile semiconductor memory device | |
US8634261B2 (en) | Semiconductor memory device and method of operating the same | |
JP2008130123A (en) | Nonvolatile semiconductor memory device | |
US11276475B2 (en) | Memory device and method of operating the memory device | |
US11462274B2 (en) | Semiconductor memory device reducing bit line precharge operation time and method of operating the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SHANGHAI HUAHONG GRACE SEMICONDUCTOR MANUFACTURING Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:YANG, GUANGJUN;REEL/FRAME:037454/0448 Effective date: 20151214 |
|
STCF | Information on status: patent grant |
Free format text: PATENTED CASE |
|
FEPP | Fee payment procedure |
Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY |
|
MAFP | Maintenance fee payment |
Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY Year of fee payment: 4 |