This application claims the benefit of priority to German application number 10339894.5, filed on Aug. 29, 2003, the contents of which are hereby incorporated by reference.
The invention relates to a sense amplifier connecting/disconnecting circuit arrangement, and to a method for operating such a circuit arrangement.
With semiconductor memory devices, one differentiates between so-called functional memory devices (e.g. PLAs, PALs, etc.), and so-called table memory devices, e.g. ROM devices (ROM=Read Only Memory), and RAM devices (RAM=Random Access Memory or write-read memory, respectively).
A RAM device is a memory for storing data under a predetermined address and for reading out the data under this address later.
The corresponding address may be input in the RAM device via so-called address input pins. For inputting and outputting the data, a plurality of, e.g. 16, so-called data input/output pins (I/Os or Inputs/Outputs) are provided. By applying an appropriate signal (e.g. a Read/Write signal) to a write/read selection pin, it can be selected whether (currently) data are to be stored or to be read out.
Since it is intended to accommodate as many memory cells as possible in a RAM device, one has been trying to realize same as simple as possible. In the case of so-called SRAMs (SRAM=Static Random Access Memory), the individual memory cells consist e.g. of few, for instance 6, transistors, and in the case of so-called DRAMs (DRAM=Dynamic Random Access Memory) in general only of one single, correspondingly controlled capacitor, with the capacitance of which one bit each can be stored as charge. This charge, however, remains for a short time only. Therefore, a so-called “refresh” must be performed regularly, e.g. approximately every 64 ms.
For technological reasons, the individual memory cells in memory devices, in particular DRAM devices, are arranged positioned side by side in a plurality of rows and columns—in a rectangular matrix (regularly divided into a plurality of cell fields) or in a rectangular array (regularly divided into a plurality of cell fields).
In order to obtain a correspondingly high total storage capacity, and/or to achieve a data read or write rate as high as possible, instead of one single array, there may be provided a plurality of, e.g. four—substantially rectangular—individual arrays in one single RAM device or chip (“multi-bank chip”) (so-called “memory banks”).
In order to perform a write or read access, a particular, predetermined sequence of instructions must be gone through:
For instance, by means of a word line activating instruction (activate instruction (ACT)), a corresponding word line—in particular assigned to a particular array—(and defined by the row address) is first of all activated.
The result thereof is that the data values stored in the memory cells assigned to the corresponding word line are read out by the sense amplifiers assigned to the corresponding word line (“activated state” of the word line).
Subsequently—by means of an appropriate read or write instruction (Read (RD) or Write (WT) instruction)—it is caused that the corresponding data—then exactly specified by the corresponding column address—are appropriately output by the corresponding sense amplifier(s)—assigned to the bit line specified by the column address—(or—vice versa—the data are read into the corresponding memory cells).
Next—by means of a word line deactivating instruction (e.g. a precharge instruction (PRE instruction))—the corresponding word line is again deactivated, and the corresponding array is prepared for the next word line activating instruction (activate instruction (ACT)). The above-mentioned sense amplifiers are each arranged in a sense amplifier region positioned between two cell fields, wherein—for reasons of space—one and the same sense amplifier may be assigned to two different cell fields each (namely the two cell fields directly adjacent to the corresponding sense amplifier region) (so-called shared sense amplifiers).
Depending on whether data are to be read out from the cell field positioned at the left or at the right next to the respective sense amplifier (or the cell field positioned above or below the respective sense amplifier), the corresponding sense amplifier is connected to the corresponding cell field by means of appropriate switches (in particular to the corresponding bit line assigned to the respective cell field) (or is connected electrically with the corresponding cell field, in particular the corresponding bit line assigned to the respective cell field), or is disconnected from the corresponding cell field (or the corresponding bit line assigned to the respective cell field) (or disconnected electrically from the corresponding cell field (or the corresponding bit line assigned to the respective cell field).
The corresponding switches effecting the connecting or disconnecting, respectively, in particular transistors, are controlled by an appropriate control line (MUX lines, in particular a right MUX line (MUXR line) and a left MUX line(MUXL line))—positioned—parallel to the word lines—at the left or at the right next to the cell fields in the above-mentioned sense amplifier regions (and above or below regions adjacent thereto).
The control signals (MUXR or MUXL signal, respectively) applied at the MUX lines are driven by a driver device (MUX driver device) connected with the corresponding MUX line, said driver device being arranged in a region positioned below or above (or at the right or at the left of) all cell fields of the corresponding array, e.g. a segment control region (i.e. an edge region of the array).
The MUX lines may be relatively long. This results in relatively large signal delays of the control signals (MUX signals) applied at the MUX lines, and to a relatively low switching rate during the connecting and/or disconnecting of the sense amplifiers to or from the corresponding cell field (or the bit line assigned to the corresponding cell field, respectively).
The invention provides a novel sense amplifier connecting/disconnecting circuit arrangement, and a novel method for operating a sense amplifier connecting/disconnecting circuit arrangement.
In one embodiment of the invention, there is a sense amplifier connecting/disconnecting circuit arrangement, in particular for a semiconductor memory device, is provided, including a switching device for connecting a sense amplifier device to a bit line or to a cell field region, respectively, and for disconnecting the sense amplifier device from the bit line or from the cell field region, respectively, as a function of the state of a control signal (MUXL, MUXR) applied at a control line, a driver device for driving the control signal (MUXL, MUXR), where an additional device, in particular an additional switch, is provided, by means of which a change of state of the control signal (MUXL, MUXR) applied at the control line can be effected.
Advantageously, the additional device, in particular the additional switch, is positioned—in contrast to the driver device—relatively close to the sense amplifier device.
By the—additional—providing of the switch, the corresponding sense amplifier device can—other than with prior art—be disconnected from the corresponding cell field region (or the corresponding bit line, respectively) relatively quickly.
In the following, the invention will be explained in detail with respect to exemplary embodiments and the enclosed drawings. In the drawings:
The semiconductor memory device 1 may, for instance, be a table memory device based on CMOS technology, e.g. a RAM memory device (RAM=Random Access Memory or write-read memory, respectively), in particular a DRAM memory device (DRAM=Dynamic Random Access Memory or dynamic write-read memory, respectively).
In the semiconductor memory device 1—after the input of a corresponding address (e.g. by the memory controller 5)—data may be stored under the respective address, and may be read out again later under this address.
The address may be input in several steps, e.g. two successive steps (e.g. first of all a row address—and possibly parts of a column address) (and/or possibly further address parts, or parts thereof)—, and then the column address (or the remaining parts of the column address, respectively, and/or—only now—the above-mentioned further address parts (or the remaining parts thereof, respectively)).
By applying an appropriate control signal (e.g. a read/write signal)—e.g. by the memory controller 5—there may be selected whether data are to be stored or to be read out.
The data input in the semiconductor memory device 1 are, as will be explained in more detail in the following, stored in corresponding memory cells there, and are read out from the corresponding memory cells later again.
Every memory cell consists e.g. of few elements, in particular only of one single, correspondingly controlled capacitor, with the capacitance of which one bit each can be stored as charge.
As results from
As is further illustrated in
By providing a plurality of substantially independent arrays 3a, 3b, 3c, 3d there can be achieved that corresponding write or read accesses can be performed—in parallel or overlapping in time—with a plurality of different arrays 3a, 3b, 3c, 3d.
The above-mentioned address (input in the semiconductor memory device 1 or the memory controller 5, respectively) comprises—as a part of the above-mentioned further address parts—a corresponding number of (here e.g. two) bits (array selection bits or bank address bits, respectively) serving to address the respectively desired array 3a, 3b, 3c, 3d during the storing or reading out of data.
As will be explained in more detail in the following, the above-mentioned memory cells are arranged in the arrays 3a, 3b, 3c, 3d each in corresponding cell fields or cell field regions 7a, 7b, 7c, 7d that are positioned vertically one on top of the other or horizontally side by side, respectively (cf. e.g. the cell field regions 7a, 7b, 7c, 7d illustrated by way of example in
The cell field regions 7a, 7b, 7c, 7d each are of substantially identical construction, substantially of rectangular (or e.g. square) design, and each comprise a particular number of memory cells positioned side by side in a plurality of rows and columns.
Between every two cell fields 7a, 7b, 7c, 7d (or—in the representation pursuant to
As results from
In accordance with
In each of the segment driver regions 8a, 8b, 8c, 8d, a plurality of corresponding segment or word line driver means are arranged.
As results from
As results from
The individual word lines 12 are—equidistantly—arranged in parallel to one another (and extend parallel to the outer edge of the respective cell field region 7a, 7b, 7c, 7d).
As results further from
The number of bit lines 12 provided per cell field region 7a, 7b, 7c, 7d may, for instance, correspond to the number of memory cell columns in the respective cell field region 7a, 7b, 7c, 7d, or e.g. to a multiple thereof.
The individual bit lines or bit line pairs 13a, 13b or 13c, 13d, respectively, are—equidistantly—arranged in parallel to one another (and extend parallel to the outer edge of the respective cell field region 7a, 7b, 7c, 7d, and perpendicular to the above-mentioned word lines 12).
The—central—memory controller 5 may—as is illustrated by way of example in
Alternatively, the memory controller 5 may e.g. also be arranged on one and the same chip 1 as the above-mentioned memory cell arrays 3a, 3b, 3c, 3d (memory banks 0-3).
In order to perform a write or read access in the semiconductor memory device 1, a particular, predetermined sequence of instructions must be gone through:
For instance, by means of a word line activating instruction (activate instruction (ACT)), a corresponding word line 12 or row of memory cells, respectively, assigned to a particular array 3a, 3b, 3c, 3d determined by the above-mentioned address (in particular the above-mentioned array selection bits or bank address bits, respectively) (and also defined by the above-mentioned address, in particular the respective row address) is activated.
This is e.g. effected by that—as is illustrated in
As has already been explained above, a plurality of sense amplifiers 11 is arranged in each of the sense amplifier regions 10a, 10b, 10c, 10d, 10e, 10f of the respective array 3a, 3b, 3c, 3d, wherein the corresponding sense amplifiers 11 (or more exactly: the sense amplifiers arranged in the sense amplifier regions 10b, 10c positioned between two different cell field regions 7a, 7b, 7c, 7d positioned side by side) each are assigned to two different cell field regions 7a, 7b, 7c, 7d (namely the cell field regions 7a, 7b, etc. directly adjacent to the corresponding sense amplifier region 10b).
Therefore, it must be ensured (e.g. by the memory controller 5) that word lines 12 are not activated—in parallel or simultaneously—that are assigned to two different cell field regions 7a, 7b which are, however, adjacent to one and the same sense amplifier region 10b, or—in parallel or simultaneously—cell field regions 7a, 7b adjacent to one and the same sense amplifier region 10b (word lines 12 in at most every second cell field region 7a, 7b—positioned side by side at the right or at the left, respectively, in the representation pursuant to
In response to the receipt of the above-mentioned word line activating instruction signal (ACT signal), the respective array controller 6a, 6b, 6c, 6d provided separately for each array 3a, 3b, 3c, 3d and receiving the respective ACT signal, causes the data values stored in the respective row—defined by the respective row address—of memory cells arranged in the corresponding cell field region 7a, 7b, 7c, 7d to be read out from the sense amplifiers 11—assigned to the corresponding word line 12—of the respective sense amplifier region 10a, 10b, 10c, 10d, 10e, 10f (“activated state” of the word line 12).
This word line 12 is kept in the activated state until an access to a further word line—arranged in the same array 3a, 3b, 3c, 3d—is to be performed, or—alternatively—until an access to a further word line of a further cell field region 7a, 7b, 7c, 7d is to be performed, which is adjacent to one and the same sense amplifier region 10b, such as the cell field region 7a, 7b, 7c, 7d of the—as explained above—activated word line 12 (or to a further word line—differing from the activated word line 12—in the same cell field region 7a, 7b, 7c, 7d as the activated word line 12).
Then—by means of a word line deactivating instruction (e.g. a precharge instruction (PRE instruction)) transmitted via a control line assigned to the respective array 3a, 3b, 3c, 3d to be addressed (or the array controller 6a, 6b, 6c, 6d thereof) (or alternatively e.g. to arrays 3a, 3b, 3c, 3d (or array controllers 6a, 6b, 6c, 6d) of the semiconductor memory device 1)—the corresponding word line 12 deactivated again, and the corresponding array 3a, 3b, 3c, 3d is prepared for the next word line activating instruction (activate instruction (ACT)).
As long as the word line 12 is left in the above-mentioned activated state, the memory controller 5 of the semiconductor memory device 1 will not send a corresponding word line deactivating instruction signal (precharge or PRE instruction signal) characterizing the word line 12 to be deactivated with a corresponding address.
E.g. one or two clocks after the above-mentioned word line activating signal (ACT signal), the memory controller 5 sends, via a control line assigned to the respective array 3a, 3b, 3c, 3d to be addressed (or the array controller 6a, 6b, 6c, 6d thereof) (or alternatively e.g. to arrays 3a, 3b, 3c, 3d (or array controllers 6a, 6b, 6c, 6d, respectively) of the semiconductor memory device 1) a corresponding read or write instruction signal (Read (RD) or Write (WT) instruction signal).
In response to the receipt of the above-mentioned read or write instruction signal (Read (RD) or Write (WT) instruction signal), the respective array controller 6a, 6b, 6c, 6d provided separately for each array 3a, 3b, 3c, 3d and receiving the respective RD (or WT) instruction signal, causes the corresponding data—then exactly specified by the corresponding column address—to be correspondingly output by the corresponding sense amplifier(s) 11 assigned to the bit line BL or the bit line pair BLLt, BLLc or BLRt, BLRc, respectively, specified by the column address (or—vice versa—the data to be read into the corresponding memory cells).
As already explained above, the sense amplifiers 11 each are arranged in a sense amplifier region 10 positioned between two cell field regions 7a, 7b, wherein—for reasons of space—one and the same sense amplifier 11 is assigned to two different cell field regions 7a, 7b each (namely the two cell field regions 7a, 7b directly adjacent to the corresponding sense amplifier region 10b) (so-called shared sense amplifiers).
Depending on whether—in the representation pursuant to
To this end, according to
The corresponding switches, in particular transistors 14a, 14b or 14c, 14d (which are correspondingly switched on or off, as explained above), effecting the connecting or disconnecting of the cell field regions 7a or 7b or of the bit line/the bit line pair 13a, 13b or 13c, 13d, respectively, to or from the corresponding sense amplifier 11, are controlled by a corresponding control line 15, 16.
Whenever a “logically high” signal (i.e. a “logically high” MUXL signal for the transistors 14a, 14b—positioned at the left of the sense amplifier 11 in the representation of
Correspondingly vice versa, whenever a “logically low” signal (i.e. a “logically low” MUXL signal for the transistors 14a, 14b—positioned at the left of the sense amplifier 11 in the representation of
The—in the representation of
The MUXL line 21 extends—parallel to the word lines 12, and positioned at the left of the corresponding sense amplifiers 11 in the representation of
Correspondingly, the MUXR line 22 extends—parallel to the word lines 12, and positioned at the right of the corresponding sense amplifiers 11 in the representation of
The MUXL line 21 is connected to the (central) MUX control line driver device 20a, and the MUXR line 22 is connected to the (central) MUX control line driver device 20b.
As is illustrated in
The n-channel MOSFET 24c is connected with the mass potential via a line 25a, and—via a line 25b—with the corresponding MUXL or MUXR line 21 or 22, and—via lines 25c or 25d, respectively,—with the p-channel MOSFET 24a and the p-channel MOSFET 24b.
The p-channel MOSFET 24b is connected via a line 25e to a (first) supply voltage—having a first voltage level—, and the p-channel MOSFET 24a is connected via a line 25f to a (second) supply voltage—having a second voltage level differing from the first voltage level.
If—by means of a corresponding signal applied at the transistor control line 23c—the n-channel MOSFET 24c is placed in a conductive state, and—by means of corresponding signals applied at the transistor control lines 23a, 23b—the p-channel MOSFETs 24a, 24b are placed in a locked state, a “logically low” MUXL or MUXR signal, respectively, is output at the corresponding MUXL or MUXR line 21 or 22 (and thus also at the control lines 15 or 16 connected thereto and shown in
Accordingly, if—by means of a corresponding signal applied at the transistor control line 23c—the n-channel MOSFET 24c is placed in a locked state, and—by means of corresponding signals applied at the transistor control lines 23a, 23b—the p-channel MOSFET 24b is placed in a conductive state and the p-channel MOSFET 24a is placed in a locked state, a “logically high” MUXL or MUXR signal, respectively, having the above-mentioned first voltage level, is output at the corresponding MUXL or MUXR line 21 or 22 (and thus also at the control lines 15 or 16 connected thereto and shown in
Correspondingly, if—by means of a corresponding signal applied at the transistor control line 23c—the n-channel MOSFET 24c is placed in a locked state, and—by means of corresponding signals applied at the transistor control lines 23a, 23b—the p-channel MOSFET 24a is placed in a conductive state and the p-channel MOSFET 24b is placed in a locked state, a “logically high” MUXL or MUXR signal, respectively, having the second voltage level differing from the first voltage level, is output at the corresponding MUXL or MUXR line 21 or 22 (and thus also at the control lines 15 or 16 connected thereto and shown in
In order to be able to quickly place the MUXL or MUXR signal, respectively, from a “logically high” to a “logically low” state, there are, as is e.g. illustrated in
The transistors 26, 27 may—as is illustrated in
For each MUXL or MUXR line 21, 22, respectively, there may—as is illustrated in
As results from
Correspondingly similar, the transistor 27—which is adapted to draw the MUXR line 22 locally downwards or to a logically low state, respectively—(and possibly the above-mentioned further, additional transistors which are adapted to—additionally—draw the MUXR line 22 downwards or to a logically low state, respectively) is, by means of a line 31a (or the possibly provided, additional transistors are, by means of corresponding, further lines) connected to the MUXR line 22, and—by means of a line 31b (or the possibly provided, additional transistors by means of corresponding, further lines)—to the mass potential. The transistors 26, 27 (and the possibly provided, further transistors) are adapted to draw the MUXL or MUXR line 21, 22, respectively,—together with the corresponding MUX control line driver devices 20a, 20b (or, alternatively, independently thereof)—locally downwards or to a logically low state, respectively, by the fact that the corresponding transistors 26, 27 are placed in a conductive state, i.e. are switched on.
To this end, a logically high control signal is applied to a control line input—connected with a corresponding transistor control line 30c or 31c, respectively—of the corresponding transistor 26 or 27, respectively.
This renders it possible to quickly draw the MUXL or the MUXR signal, respectively, downwards or to a logically low state, respectively, without complete intermediate amplifiers having to be provided in the respective intersection regions 28 (or sense amplifier regions 10b) (the intermediate amplifiers having—other than the transistors 26, 27—to be connected, except with the mass potential, additionally, e.g. via one or a plurality of further transistors, with the above-mentioned first supply voltage having the first voltage level (and possibly additionally with the above-mentioned second supply voltage having the above-mentioned second, differing voltage level).
Advantageously, the same signals can be used as control signals for the transistors 26, 27 as are used for controlling the above-mentioned equalizer devices 17, 18 illustrated in
In particular—for controlling the transistors 27 drawing the MUXR line 22, 16 downwards or to a logically low state, respectively—an EQLL signal can be used that is applied at a control line 32—positioned at the left of the corresponding sense amplifiers 11—and is used to control the equalizer devices 17 positioned at the left of the corresponding sense amplifiers 11 and opposite to the MUXR line 16, 22 that is, in the representation of
Correspondingly—for controlling the transistor 26 drawing the MUXL line 21, 15 downwards or to a logically low state, respectively—an EQLR signal can be used that is applied at a control line 33—positioned at the right of the corresponding sense amplifiers 11—and is used to control the equalizer devices 18 positioned at the right of the corresponding sense amplifiers 11 and opposite to the MUXL line 15, 21 that is, in the representation of
By means of the equalizer devices 17, 18—correspondingly similar as with conventional equalizer devices 17, 18—depending on the state of the EQLL or EQLR signal applied at the control lines 32 or 33, respectively—either i) the sense amplifier 11 assigned to the respective equalizer device 17, 18 is kept in a “precharge state” (wherein the corresponding cell field region 7a, 7b cannot be activated), or ii) the sense amplifier 11 assigned to the respective equalizer device 17, 18 is released again from the “precharge state” (so that the corresponding cell field region 7a, 7b may then be activated).
Instead of with the above-mentioned EQLL or EQLR signals, respectively, applied at the control lines 32 or 33, respectively, in the case of a second, alternative embodiment illustrated in
In this embodiment, the local driver is provided at the beginning of the master word line (MWL)—as is indicated in
Number | Date | Country | Kind |
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103 39 894.5 | Aug 2003 | DE | national |