U.S. patent application number 16/003996 was filed with the patent office on 2019-12-12 for circuitry for tracking bias voltage behavior.
The applicant listed for this patent is Arm Limited. Invention is credited to Rajesh Reddy Challa, Rahul Mathur, Gaurang Prabhakar Narvekar.
Application Number | 20190378550 16/003996 |
Document ID | / |
Family ID | 68696015 |
Filed Date | 2019-12-12 |
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United States Patent
Application |
20190378550 |
Kind Code |
A1 |
Mathur; Rahul ; et
al. |
December 12, 2019 |
CIRCUITRY FOR TRACKING BIAS VOLTAGE BEHAVIOR
Abstract
Various implementations described herein refer to an integrated
circuit having dummy wordline driver circuitry coupled to a dummy
wordline and dummy bitline pulldown circuitry coupled between a
dummy bitline and the dummy wordline. The integrated circuit may
include dummy wordline tracking circuitry coupled to the dummy
wordline between the dummy wordline driver circuitry and the dummy
bitline pulldown circuitry. The dummy wordline tracking circuitry
may have one or more variable capacitors that are coupled between
the dummy wordline and a variable voltage source.
Inventors: |
Mathur; Rahul; (Austin,
TX) ; Challa; Rajesh Reddy; (Austin, TX) ;
Narvekar; Gaurang Prabhakar; (Austin, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Arm Limited |
Cambridge |
|
GB |
|
|
Family ID: |
68696015 |
Appl. No.: |
16/003996 |
Filed: |
June 8, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G11C 11/419 20130101;
G11C 11/412 20130101; G11C 7/227 20130101; G11C 8/08 20130101; G11C
7/12 20130101 |
International
Class: |
G11C 7/22 20060101
G11C007/22; G11C 7/12 20060101 G11C007/12; G11C 8/08 20060101
G11C008/08 |
Claims
1. An integrated circuit, comprising: dummy wordline driver
circuitry coupled to a dummy wordline; dummy bitline pulldown
circuitry coupled between a dummy bitline and the dummy wordline;
and dummy wordline tracking circuitry coupled to the dummy wordline
between the dummy wordline driver circuitry and the dummy bitline
pulldown circuitry, wherein the dummy wordline tracking circuitry
has one or more variable capacitors that are coupled between the
dummy wordline and a variable voltage source comprising a variable
source voltage supply.
2. An integrated circuit, comprising: dummy wordline driver
circuitry coupled to a dummy wordline; dummy bitline pulldown
circuitry coupled between a dummy bitline and the dummy wordline;
and dummy wordline tracking circuitry coupled to the dummy wordline
between the dummy wordline driver circuitry and the dummy bitline
pulldown circuitry, wherein the dummy wordline tracking circuitry
has one or more variable capacitors that are coupled between the
dummy wordline and a variable voltage source; wherein the one or
more variable capacitors are used for switching between multiple
capacitance values, and wherein the switching is performed
dynamically.
3. The integrated circuit of claim 2, wherein the switching between
multiple capacitance values occurs at any time within a memory
operation cycle.
4-5. (canceled)
6. The integrated circuit of claim 1, wherein the one or more
variable capacitors have a first terminal that is coupled to the
dummy wordline.
7. An integrated circuit, comprising: dummy wordline driver
circuitry coupled to a dummy wordline; dummy bitline pulldown
circuitry coupled between a dummy bitline and the dummy wordline;
and dummy wordline tracking circuitry coupled to the dummy wordline
between the dummy wordline driver circuitry and the dummy bitline
pulldown circuitry, wherein the dummy wordline tracking circuitry
has one or more variable capacitors that are coupled between the
dummy wordline and a variable voltage source; wherein the one or
more variable capacitors have a first terminal that is coupled to
the dummy wordline; wherein the one or more variable capacitors
have a second terminal that is coupled to the variable voltage
source to receive a control signal that switches between a first
state and a second state that is different than the first
state.
8. The integrated circuit of claim 7, wherein in the first state,
the one or more variable capacitors have a first variable
capacitance value that is high in capacitance, and wherein in the
second state, the one or more variable capacitors have a second
variable capacitance value is low in capacitance.
9. The integrated circuit of claim 1, wherein the one or more
variable capacitors are implemented with a transistor that is
coupled together to operate as a capacitor.
10. An integrated circuit, comprising: dummy wordline driver
circuitry coupled to a dummy wordline; dummy bitline pulldown
circuitry coupled between a dummy bitline and the dummy wordline;
and dummy wordline tracking circuitry coupled to the dummy wordline
between the dummy wordline driver circuitry and the dummy bitline
pulldown circuitry, wherein the dummy wordline tracking circuitry
has one or more variable capacitors that are coupled between the
dummy wordline and a variable voltage source; wherein the one or
more variable capacitors are implemented with a transistor that is
coupled together to operate as a capacitor; wherein the one or more
variable capacitors have a first terminal that is a gate of the
transistor.
11. The integrated circuit of claim 10, wherein the one or more
variable capacitors have a second terminal that is a source/drain
connection of the transistor.
12. An integrated circuit, comprising: dummy bitline pulldown
circuitry coupled to a dummy bitline; global timing pulse reset
circuitry coupled between a dummy wordline and the dummy bitline;
and dummy bitline tracking circuitry coupled to the dummy bitline
between the dummy bitline pulldown circuitry and the global timing
pulse reset circuitry, wherein the dummy bitline tracking circuitry
has one or more variable capacitors that are coupled between the
dummy bitline and a variable voltage source comprising a variable
source voltage supply.
13. An integrated circuit, comprising: dummy bitline pulldown
circuitry coupled to a dummy bitline; global timing pulse reset
circuitry coupled between a dummy wordline and the dummy bitline;
and dummy bitline tracking circuitry coupled to the dummy bitline
between the dummy bitline pulldown circuitry and the global timing
pulse reset circuitry, wherein the dummy bitline tracking circuitry
has one or more variable capacitors that are coupled between the
dummy bitline and a variable voltage source; wherein the one or
more variable capacitors are used for dynamically switching between
multiple capacitance values at any time within a memory operation
cycle.
14. (canceled)
15. (canceled)
16. An integrated circuit, comprising: dummy bitline pulldown
circuitry coupled to a dummy bitline; global timing pulse reset
circuitry coupled between a dummy wordline and the dummy bitline;
and dummy bitline tracking circuitry coupled to the dummy bitline
between the dummy bitline pulldown circuitry and the global timing
pulse reset circuitry, wherein the dummy bitline tracking circuitry
has one or more variable capacitors that are coupled between the
dummy bitline and a variable voltage source; wherein the one or
more variable capacitors are implemented with a transistor that is
coupled together to operate as a capacitor, wherein the one or more
variable capacitors have a first terminal that is a gate of the
transistor, and wherein the one or more variable capacitors have a
second terminal that is a source/drain connection of the
transistor.
17. (canceled)
18. An integrated circuit, comprising: dummy wordline driver
circuitry coupled to a dummy wordline; dummy bitline pulldown
circuitry coupled between a dummy bitline and the dummy wordline;
global timing pulse reset circuitry coupled between the dummy
wordline and the dummy bitline; dummy wordline tracking circuitry
coupled to the dummy wordline between the dummy wordline driver
circuitry and the dummy bitline pulldown circuitry, wherein the
dummy wordline tracking circuitry has at least one first variable
capacitor that is coupled between the dummy wordline and a first
variable voltage source; and dummy bitline tracking circuitry
coupled to the dummy bitline between the dummy bitline pulldown
circuitry and the global timing pulse reset circuitry, wherein the
dummy bitline tracking circuitry has at least one second variable
capacitor that is coupled between the dummy bitline and a second
variable voltage source; wherein the first variable voltage source
is a variable source voltage supply.
19. An integrated circuit, comprising: dummy wordline driver
circuitry coupled to a dummy wordline; dummy bitline pulldown
circuitry coupled between a dummy bitline and the dummy wordline;
global timing pulse reset circuitry coupled between the dummy
wordline and the dummy bitline; dummy wordline tracking circuitry
coupled to the dummy wordline between the dummy wordline driver
circuitry and the dummy bitline pulldown circuitry, wherein the
dummy wordline tracking circuitry has at least one first variable
capacitor that is coupled between the dummy wordline and a first
variable voltage source; and dummy bitline tracking circuitry
coupled to the dummy bitline between the dummy bitline pulldown
circuitry and the global timing pulse reset circuitry, wherein the
dummy bitline tracking circuitry has at least one second variable
capacitor that is coupled between the dummy bitline and a second
variable voltage source; wherein the second variable voltage source
is a variable source voltage supply.
20. The integrated circuit of claim 18, wherein the at least one
first variable capacitor and the at least one second variable
capacitor are implemented with a transistor that is coupled
together to operate as a capacitor, wherein the at least one
variable capacitor have a first terminal that is a gate of the
transistor, and wherein the at least one variable capacitor have a
second terminal that is a source/drain connection of the
transistor.
21. The integrated circuit of claim 19, wherein the at least one
first variable capacitor and the at least one second variable
capacitor are implemented with a transistor that is coupled
together to operate as a capacitor, wherein the at least one
variable capacitor have a first terminal that is a gate of the
transistor, and wherein the at least one variable capacitor have a
second terminal that is a source/drain connection of the
transistor.
Description
BACKGROUND
[0001] This section is intended to provide information relevant to
understanding the various technologies described herein. As the
section's title implies, this is a discussion of related art that
should in no way imply that it is prior art. Generally, related art
may or may not be considered prior art. It should therefore be
understood that any statement in this section should be read in
this light, and not as any admission of prior art.
[0002] Generally, the switching behavior of a transistor, such as,
e.g., a metal-oxide-semiconductor field effect transistor (MOSFET),
is affected by the parasitic capacitances between the device's
three terminals, that is, gate-to-source (CGS), gate-to-drain (CGD)
and drain-to-source (CDS) capacitances. These capacitance values
are non-linear and a function of the device structure, geometry,
and bias voltages. The capacitances come from a series combination
of a bias independent oxide capacitance and a bias dependent
depletion (Silicon) capacitance. Also, the input capacitance
(CGD+CGS) may decrease with increasing voltage at shorted
drain/source terminals due to a decrease in depletion capacitance,
as voltage increases and the depletion region widens. Also, the
lower the input capacitance, the faster the switching speed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] Implementations of various techniques are described herein
with reference to the accompanying drawings. It should be
understood, however, that the accompanying drawings illustrate only
various implementations described herein and are not meant to limit
embodiments of various techniques described herein.
[0004] FIG. 1 illustrates a diagram of memory circuitry having row
tracking logic and column tracking logic in accordance with various
implementations described herein.
[0005] FIG. 2 illustrates a diagram of dummy wordline circuitry
having tracking logic in accordance with various implementations
described herein.
[0006] FIG. 3 illustrates a diagram of dummy bitline circuitry
having tracking logic in accordance with various implementations
described herein.
[0007] FIG. 4 illustrates a diagram of dummy wordline/bitline
circuitry having tracking logic in accordance with various
implementations described herein.
[0008] FIG. 5 illustrates a process flow diagram of a method for
manufacturing an integrated circuit in accordance with various
implementations described herein.
DETAILED DESCRIPTION
[0009] Various implementations described herein are directed to
integrated circuitry for tracking bias voltage behavior in various
memory related applications. For instance, various implementations
described herein refer to tracking circuitry that utilizes changes
in transistor switching behavior with different bias voltages in
various memory self-timing applications. In some instances,
transistor switching behavior may refer to the switching behavior
of the metal-oxide-semiconductor field-effect transistor
(MOSFET).
[0010] Various implementations of tracking circuitry will now be
described in detail herein with reference to FIGS. 1-5.
[0011] FIG. 1 illustrates a diagram of memory circuitry 100 having
row tracking logic circuitry 106 and column tracking logic
circuitry 112 in accordance with implementations described herein.
As also shown in FIG. 1, the memory circuitry 100 also includes
core circuitry 102 having multiple bitcell arrays that may be
implemented with a single bank of bitcells and/or multiple banks of
bitcells.
[0012] The memory circuitry 100 may be implemented as an integrated
circuit (IC) with various types of memory, such as, e.g., random
access memory (RAM), including static RAM (SRAM), and/or any other
types of volatile memory. In various implementations, the memory
circuitry 100 may be implemented as an integrated circuit (IC) with
single or dual rail memory architecture along with any other
related circuitry. The memory circuitry 100 may be integrated with
computing circuitry and related components on a single chip, such
as, e.g., system-on-a-chip (SoC). Further, the memory circuitry 100
may be implemented in embedded systems for various electronic and
mobile applications, including low power sensor nodes for IoT
(Internet of things) applications.
[0013] As shown in FIG. 1, the memory circuitry 100 includes
memory, such as, e.g., core circuitry 102 having multiple bitcell
arrays, wherein each bitcell array may include multiple bitcells,
and each bitcell may be referred to as a memory cell, and each
bitcell may be configured to store at least one data bit value
(e.g., data value related to a logical `0` or `1`). Also, each
bitcell array may include any number of bitcells arranged in
various configurations, such as, e.g., a two-dimensional (2D)
memory array having any number of columns and any number of rows of
multiple bitcells, which may be arranged in a 2D grid pattern with
2D indexing capabilities. Further, each bitcell may be implemented
with random access memory (RAM) circuitry, and/or some other type
of volatile type memory, as applicable. For instance, each bitcell
may include a multi-transistor static RAM (SRAM) cell, including
various types of SRAM cells, such as, e.g., 6T CMOS SRAM and/or
other types of complementary MOS (CMOS) SRAM cells, such as, e.g.,
4T, 8T, 10T, or more transistors per bit. In some instances, the
memory circuitry 100 may operate at a source voltage level VDD with
a voltage range that varies with technology.
[0014] The memory circuitry 100 may include wordline (WL) row
decoder circuitry 106 that accesses each of the bitcells via a
selected wordline (WL) that is driven by wordline driver circuitry.
The combination of the WL decoder circuitry 106 and WL driver may
be referred to as (WDX). The memory circuitry 100 (including the
core circuitry 102, bitcells, and the row decoder circuitry 106)
may operate at a first supply voltage (Vdd), such as, e.g., core
supply voltage (Vddc), wherein voltage range varies with
technology. In other instances, the row decoder circuitry 106 may
operate at the core supply voltage (Vddc), and some other
components, such as, e.g., WL driver circuitry may generate a
wordline signal at a second supply voltage that may be different
than the first or core supply voltage (Vddc), such as, e.g., a
periphery supply voltage (Vddp).
[0015] As also shown in FIG. 1, the memory circuitry 100 may
include row tracking circuitry 106. In some implementations, the
row tracking circuitry 106 may refer to row tracking cells that
include one or more variable capacitors that may be used to mimic
the bitline load seen by the bitline (BL). Further, in some
implementations, the row tracking circuitry 106 may refer to dummy
bitline circuitry having dummy bitline (DBL) tracking logic that is
implemented as dummy bitline tracking circuitry 302 in reference to
FIG. 3, as described herein below. The memory circuitry 100 may
include dummy bitline pulldown circuitry 108, which may be
implemented as part of the row decoder circuitry 104.
[0016] The memory circuitry 100 may include periphery circuitry
having control circuitry 114 and column decoder circuitry, such as,
e.g., input/output (I/O) circuitry 110 that may be used to access
each of the bitcells via one or more selected bitlines BL, . . . ,
BLn. In some instances, selected bitlines BL, . . . , BLn include a
selected pair of complementary bitlines BL/NBL, . . . , BLn/NBLn.
In other instances, the periphery circuitry may include the row
decoder 106 coupled to wordline driver circuitry and column decoder
circuitry to select at least one bitcell in the arrays 102 of
bitcells with a wordline (WL) signal and a bitline (BL) signal.
Further, the periphery circuitry may operate at the periphery
supply voltage (Vddp), which is different than the core supply
voltage (Vddc).
[0017] As shown in FIG. 1, the memory circuitry 100 may include
column tracking circuitry 112. In some implementations, the column
tracking circuitry 112 may refer to column tracking cells that
include one or more variable capacitors that are used to mimic the
wordline load seen by the wordline (WL). Also, in some
implementations, the column tracking circuitry 112 may refer to
dummy wordline circuitry having dummy wordline (DWL) tracking logic
that may be implemented as dummy wordline tracking circuitry 202 in
reference to FIG. 2, as described herein below. The memory
circuitry 100 may include dummy wordline driver circuitry 116 and
global timing pulse (GTP) reset circuitry 118, which may be
implemented as part of the control circuitry 114.
[0018] FIG. 2 illustrates a diagram of dummy wordline circuitry 200
having dummy wordline (DWL) tracking logic in accordance with
implementations described herein. One or more various components
that are described in FIG. 2 are similar in scope, function, and
operation as described in reference to the circuitry 100 as shown
in FIG. 1.
[0019] As shown in FIG. 2, the dummy wordline circuitry 200
includes dummy bitline pulldown circuitry 108, dummy wordline
driver circuitry 116, and global timing pulse (GTP) reset circuitry
118 that are coupled together with a dummy wordline (dwl) and a
dummy bitline (dbl). In some implementations, the dummy wordline
driver circuitry 116 may be coupled to the dummy wordline (dwl).
The dummy bitline pulldown circuitry 108 may be coupled between the
dummy bitline (dbl) and the dummy wordline (dwl). The global timing
pulse (GTP) reset circuitry 118 may be coupled between the dummy
bitline pulldown circuitry 108 and the dummy wordline driver
circuitry 116.
[0020] In some implementations, during operation, the global timing
pulse (GTP) reset circuitry 118 may receive a dbl_turn signal from
the dummy bitline pulldown circuitry 108 via the dummy bitline
(dbl). In this instance, the global timing pulse (GTP) reset
circuitry 118 may provide a complementary global timing pulse
signal (ngtp) to the dummy wordline driver circuitry 116 based on
the dbl_turn signal. The dummy wordline driver circuitry 116 may be
implemented with an inverter to drive the dummy wordline (dwl). In
this instance, the dummy wordline driver circuitry 116 receives the
complementary global timing pulse signal (ngtp) and provides an
inverted ngtp signal (gtp signal) as a dwl_turn signal to the dummy
bitline pulldown circuitry 108 via the dummy wordline (dwl). Based
on the received dwl_turn signal, the dummy bitline pulldown
circuitry 108 provides the dbl_turn signal to the global timing
pulse (GTP) reset circuitry 118 via the dummy bitline (dbl).
[0021] The dummy wordline circuitry 200 includes tracking logic
that is implemented as dummy wordline tracking circuitry 202, which
may be coupled to the dummy wordline (dwl) between the dummy
wordline driver circuitry 116 and the dummy bitline pulldown
circuitry 108. The dummy wordline tracking circuitry 202 may
include dummy wordline tracking cells that include one or more
variable capacitors that are used to mimic the wordline load seen
by the wordline (WL). For instance, the dummy wordline tracking
circuitry 202 may include one or more variable capacitors (T1, T2,
T3, T4) that are coupled between the dummy wordline (dwl) and a
variable voltage source (control_1), which may be referred to a
first variable voltage source. The one or more variable capacitors
(T1, T2, T3, T4) may be used for switching between multiple
capacitance values, and switching may be achieved and/or performed
dynamically. Switching between multiple capacitance values may
occur at any time within a memory operation cycle. In some
instances, the variable voltage source (control_1) may refer to a
control signal that is implemented with a variable source voltage
supply (Vdd). In other instances, the variable voltage source may
be implemented with a variable ground voltage supply (Vss).
[0022] In some implementations, the one or more variable capacitors
(T1, T2, T3, T4) may have a first terminal that is coupled to the
dummy wordline (dwl). The one or more variable capacitors (T1, T2,
T3, T4) may have a second terminal that is coupled to the variable
voltage source (control_1) to receive at least one control signal
that switches between a first state and a second state that is
different than the first state. For instance, in the first state,
the one or more variable capacitors (T1, T2, T3, T4) may have a
first variable capacitance value that is high in capacitance. Also,
in another instance, in the second state, the one or more variable
capacitors (T1, T2, T3, T4) may have a second variable capacitance
value is low in capacitance.
[0023] In some implementations, as also shown in FIG. 2, the one or
more variable capacitors (T1, T2, T3, T4) may be implemented with a
transistor that is coupled together to operate as a capacitor. The
transistor may be implemented with a MOSFET, such as, e.g., an
n-type MOSFET (nMOSFET). However, in some other scenarios, the
transistor may also be implemented with a p-type MOSFET (pMOSFET).
Further, the one or more variable capacitors (T1, T2, T3, T4) have
a first terminal that is a gate of the transistor, and the one or
more variable capacitors (T1, T2, T3, T4) may have a second
terminal that is a source/drain connection of the transistor. In
other implementations, the one or more variable capacitors (T1, T2,
T3, T4) may be implemented with a capacitor.
[0024] In reference to various operational applications of FIG. 2,
the tracking circuitry 202 includes the dummy word line (DWL) and
the dummy bit line (DBL) with minimal slack time to trigger the
fall of the internal memory clock (GTP) for self-timing. During
read or write operations, the rise of the external clock signal
from the SoC triggers the fall of the NGTP and rise of GTP, wherein
NGTP fall triggers DWL rise, and the DWL signal travels in the
direction of the actual wordline through the IOs. The tracking
circuitry 202 seeks to mimic the DWL routing and load in the IOs to
that seen by the actual wordline (WL) in the bitcells. The DWL
signal returning from the IOs is referred to as the DWL_TURN, which
triggers the DBL fall, wherein the DBL signal is loaded with
capacitance to match that seen by the actual bitline (BL) in the
bitcell. For reference, the NGTP is one stage before the GTP, and
the GTP is the memory self-time pulse. Also, the DWL_TURN refers to
the DWL signal returning after turning around in the memory
IOs.
[0025] FIG. 3 illustrates a diagram of dummy bitline circuitry 300
having dummy bitline (DBL) tracking logic in accordance with
implementations described herein. Various components that are
described in FIG. 3 are similar in scope, function, and operation
as described in reference to the circuitry 200 as shown in FIG.
2.
[0026] As shown in FIG. 3, the dummy bitline circuitry 300 may
include the dummy bitline pulldown circuitry 108 that is coupled to
the dummy bitline (dbl). The dummy bitline circuitry 300 may
include the global timing pulse (GTP) reset circuitry 118 that is
coupled between the dummy wordline (dwl) and the dummy bitline
(dbl).
[0027] The dummy bitline circuitry 300 may include dummy bitline
tracking circuitry 302 that is coupled to the dummy bitline (dbl)
between the dummy bitline pulldown circuitry 108 and the global
timing pulse (GTP) reset circuitry 118. The dummy bitline tracking
circuitry 302 may include dummy bitline tracking cells that include
one or more variable capacitors that are used to mimic the bitline
load seen by the bitline (BL). For instance, the dummy bitline
tracking circuitry 302 may include one or more variable capacitors
(T5, T6, T7, T8) that are coupled between the dummy bitline (dbl)
and a variable voltage source (control_2), which may be referred to
a second variable voltage source. The one or more variable
capacitors (T5, T6, T7, T8) may be used for dynamically switching
between multiple capacitance values at any time within a memory
operation cycle. Also, the variable voltage source (control_2)
refers to another control signal that is implemented with a
variable source voltage supply (Vdd). In some other instances, the
variable voltage source may be implemented with a variable ground
voltage supply (Vss).
[0028] In some implementations, the one or more variable capacitors
(T5, T6, T7, T8) may have a first terminal that is coupled to the
dummy bitline (dbl). The one or more variable capacitors (T5, T6,
T7, T8) may have a second terminal that is coupled to the variable
voltage source (control_2) to receive at least one control signal
that switches between a first state and a second state that is
different than the first state. For instance, in the first state,
the one or more variable capacitors (T5, T6, T7, T8) may have a
first variable capacitance value that is high in capacitance. Also,
in another instance, in the second state, the one or more variable
capacitors (T5, T6, T7, T8) may have a second variable capacitance
value is low in capacitance.
[0029] In some implementations, as also shown in FIG. 2, the one or
more variable capacitors (T5, T6, T7, T8) may be implemented with a
transistor that is coupled together to operate as a capacitor. The
transistor may be implemented with a MOSFET, such as, e.g., an
n-type MOSFET (nMOSFET). However, in some other scenarios, the
transistor may also be implemented with a p-type MOSFET (pMOSFET).
Further, the one or more variable capacitors (T5, T6, T7, T8) have
a first terminal that is a gate of the transistor, and the one or
more variable capacitors (T5, T6, T7, T8) may have a second
terminal that is a source/drain connection of the transistor. In
other implementations, the one or more variable capacitors (T5, T6,
T7, T8) may be implemented with a capacitor.
[0030] FIG. 4 illustrates a diagram of dummy wordline/bitline
circuitry having tracking logic in accordance with various
implementations described herein. Various components that are
described in FIG. 4 are similar in scope, function, and operation
as described in reference to the circuitry 200, 300 as shown in
FIGS. 2 and 3, respectively.
[0031] As shown in FIG. 4, the dummy bitline circuitry 400 may
include the dummy wordline driver circuitry 116 that is coupled to
the dummy wordline (dwl). The dummy bitline circuitry 400 may
include the dummy bitline pulldown circuitry 108 that is coupled
between the dummy bitline (dbl) and the dummy wordline (dwl). The
dummy bitline circuitry 400 may include the global timing pulse
(GTP) reset circuitry 118 that is coupled between the dummy
wordline (dwl) and the dummy bitline (dbl).
[0032] The dummy bitline circuitry 400 may include the dummy
wordline tracking circuitry 202 that is coupled to the dummy
wordline (dwl) between the dummy wordline driver circuitry 116 and
the dummy bitline pulldown circuitry 108. As shown, the dummy
wordline tracking circuitry 202 may include at least one first
variable capacitor (T1, T2, T3, T4) that is coupled between the
dummy wordline (dwl) and the first variable voltage source
(control_1).
[0033] The dummy bitline circuitry 400 may include the dummy
bitline tracking circuitry 302 that is coupled to the dummy bitline
(dbl) between the dummy bitline pulldown circuitry 108 and the
global timing pulse (GTP) reset circuitry 118. As shown, the dummy
bitline tracking circuitry 302 may include at least one second
variable capacitor (T5, T6, T7, T8) that is coupled between the
dummy bitline (dbl) and the second variable voltage source
(control_2). As described herein, the first variable voltage source
(control_1) may refer to the variable source voltage supply (Vdd)
or the variable ground voltage supply (Vss), and the second
variable voltage source (control_2) may also refer to the variable
source voltage supply (Vdd) or the variable ground voltage supply
(Vss).
[0034] In some implementations, the at least one first variable
capacitor (T1, T2, T3, T4) and the at least one second variable
capacitor (T5, T6, T7, T8) may be implemented with a transistor
that is coupled together to operate as a capacitor. Also, the at
least one variable capacitor (T1, T2, T3, T4, T5, T6, T7, T8) may
have a first terminal that is a gate of the transistor, and the at
least one variable capacitor (T1, T2, T3, T4, T5, T6, T7, T8) may
have a second terminal that is a source/drain connection of the
transistor.
[0035] In reference to the dummy wordline tracking circuitry 202,
the one or more variable capacitors (T1, T2, T3, T4) may have a
first terminal that is coupled to the dummy wordline (dwl). The one
or more variable capacitors (T1, T2, T3, T4) may have a second
terminal that is coupled to the first variable voltage source
(control_1) to receive at least one control signal that switches
between a first state and a second state that is different than the
first state. In the first state, the one or more variable
capacitors (T1, T2, T3, T4) may have a first variable capacitance
value that is high in capacitance. In the second state, the one or
more variable capacitors (T1, T2, T3, T4) may have a second
variable capacitance value is low in capacitance.
[0036] In reference to the dummy bitline tracking circuitry 302,
the one or more variable capacitors (T5, T6, T7, T8) may have a
first terminal that is coupled to the dummy bitline (dbl). The one
or more variable capacitors (T5, T6, T7, T8) may have a second
terminal that is coupled to the second variable voltage source
(control_2) to receive at least one control signal that switches
between a first state and a second state that is different than the
first state. In the first state, the one or more variable
capacitors (T5, T6, T7, T8) may have a first variable capacitance
value that is high in capacitance. In the second state, the one or
more variable capacitors (T5, T6, T7, T8) may have a second
variable capacitance value is low in capacitance.
[0037] In some implementations, as also shown in FIG. 4, the one or
more variable capacitors (T1, T2, T3, T4, T5, T6, T7, T8) may be
implemented with a transistor that is coupled together to operate
as a capacitor. The transistor may be implemented with a MOSFET,
such as, e.g., an n-type MOSFET (nMOSFET). However, in other
scenarios, the transistor may also be implemented with a p-type
MOSFET (pMOSFET). Further, the one or more variable capacitors (T1,
T2, T3, T4, T5, T6, T7, T8) have a first terminal that is a gate of
the transistor, and the one or more variable capacitors (T1, T2,
T3, T4, T5, T6, T7, T8) may have a second terminal that is a
source/drain connection of the transistor. In other
implementations, the one or more variable capacitors (T1, T2, T3,
T4, T5, T6, T7, T8) may be implemented with a capacitor.
[0038] Advantages of the various implementations described herein
refer to using the observed behavior in the memory self-timing. The
tracking circuitry 202, 302 introduces a cycle-time component (DWL
rise->DBL rise) to speedup the falling edge (e.g., second
transition) of DWL, while not affecting the rising edge (e.g.,
first transition). One way to achieve this is to connect the
shorted source/drain terminals of the dummy MOSFETs to a delayed
version of DWL, which serves the same purpose as CONTROL=VSS during
the rise transition of DWL and CONTROL=VDD during the fall
transition. Another idea to achieve the same effect is to connect
DWL_TURN to the shorted source/drain of the dummy MOSFET, instead
of Vss as shown in FIG. 4. Connecting DWL_TURN in this way leads to
an increase in loading, and an overall point from which it turns
back may be re-adjusted to a smaller number so as to match the
dummy WL tracking delay. Another similar idea may be used for dummy
MOSFETs to load DBL, wherein this idea may lead to further
cycle-time improvement. Also, this idea may have application for
pseudo 2-port memories, wherein the DWL's inability to fall quickly
and completely to the Vss level after an end of first cycle and a
beginning of second cycle may lead to loss of the write margin on
the second cycle due to slightly smaller self-timed pulse or path
(STP).
[0039] In some implementations, the self-timed path (i.e., the
circuit path involved) may refer to at least one circuit path that
is responsible for taking an external clock rise as input for
triggering the internal memory (gtp) clock rise. The self-timed
path may also refer to at least one circuit path that includes
tracking the dummy bitline (DBL) and/or the dummy wordline (DWL).
The self-timed path may also refer to tracking the DBL and/or DWL
when it leads to closing of the internal memory (gtp) clock. In
other implementations, the self-timed pulse (i.e., timing of
signals) may refer to the pulse width of the internal memory (gtp)
clock pulse and/or also to one or more or all of the derived
internal clocks from gtp or tracking.
[0040] FIG. 5 illustrates a process flow diagram of a method 500
for manufacturing an integrated circuit in accordance with various
implementations described herein.
[0041] It should be understood that even though method 500 may
indicate a particular order of operation execution, in some cases,
various certain portions of the operations may be executed in a
different order, and on different systems. In other cases,
additional operations and/or steps may be added to and/or omitted
from method 500. Method 500 may be implemented in hardware and/or
software. If implemented in hardware, the method 500 may be
implemented with various circuit components, such as described
herein above in reference to FIGS. 1-4. If implemented in software,
method 500 may be implemented as a program or software instruction
process that may be configured for implementing tracking circuitry
as described herein. Also, if implemented in software, instructions
related to implementing the method 500 may be stored in memory
and/or a database. For instance, a computer or various other types
of computing devices having a processor and memory may be
configured to perform method 500.
[0042] As described and shown in reference to FIG. 5, method 500
may be used for manufacturing of fabricating an integrated circuit
(IC) for tracking bias voltage behavior in various memory related
applications. In some implementations, method 500 may refer to
manufacturing or fabricating tracking circuitry that utilizes
changes in MOSFET switching behavior with different bias voltages
in memory self-timing applications.
[0043] At block 510, method 500 may fabricate dummy wordline driver
circuitry that is coupled to a dummy wordline. At block 520, method
500 may fabricate dummy bitline pulldown circuitry that is coupled
between a dummy bitline and the dummy wordline. At block 530,
method 500 may fabricate global timing pulse reset circuitry that
is coupled between the dummy wordline and the dummy bitline.
[0044] At block 540, method 500 may fabricate dummy wordline
tracking circuitry that is coupled to the dummy wordline between
the dummy wordline driver circuitry and the dummy bitline pulldown
circuitry. The dummy wordline tracking circuitry may have at least
one first variable capacitor that is coupled between the dummy
wordline and a first variable voltage source. The at least one
first variable capacitor may be implemented with a transistor that
is coupled together to operate as a capacitor, and the at least one
variable capacitor may have a first terminal that is a gate of the
transistor, and the at least one variable capacitor may also have a
second terminal that is a source/drain connection of the
transistor. The first variable voltage source may be implemented
with a variable source voltage supply (Vdd) or a variable ground
voltage supply (Vss).
[0045] In some implementations, the at least one first variable
capacitor may be used for switching between multiple capacitance
values, and the switching may be performed dynamically. Also, the
switching between multiple capacitance values may occur at any time
within a memory operation cycle. In some implementations, the
second terminal of the at least one first variable capacitor may be
coupled to the first variable voltage source to receive a first
control signal that switches between a first state and a second
state that is different than the first state. In the first state,
the at least one first variable capacitor may have a first variable
capacitance value that is high in capacitance, and in the second
state, the at least one first variable capacitor may have a second
variable capacitance value is low in capacitance.
[0046] At block 550, method 500 may fabricate dummy bitline
tracking circuitry that is coupled to the dummy bitline between the
dummy bitline pulldown circuitry and the global timing pulse reset
circuitry. The dummy bitline tracking circuitry may have at least
one second variable capacitor that is coupled between the dummy
bitline and a second variable voltage source. The at least one
second variable capacitor may be implemented with a transistor that
is coupled together to operate as a capacitor, and the at least one
variable capacitor may have a first terminal that is a gate of the
transistor, and the at least one variable capacitor may have a
second terminal that is a source/drain connection of the
transistor. The second variable voltage source may be implemented
with a variable source voltage supply (Vdd) or a variable ground
voltage supply (Vss).
[0047] In some implementations, the at least one second variable
capacitor may be used for switching between multiple capacitance
values, and the switching may be performed dynamically. Also, the
switching between multiple capacitance values may occur at any time
within a memory operation cycle. In some implementations, the
second terminal of the at least one second variable capacitor may
be coupled to the second variable voltage source to receive a
second control signal that switches between a second state and a
second state that is different than the first state. In the first
state, the at least one second variable capacitor may have a first
variable capacitance value that is high in capacitance, and in the
second state, the at least one second variable capacitor may have a
second variable capacitance value is low in capacitance.
[0048] Described herein are various implementations of an
integrated circuit. The integrated circuit may include dummy
wordline driver circuitry that is coupled to a dummy wordline. The
integrated circuit may include dummy bitline pulldown circuitry
that is coupled between a dummy bitline and the dummy wordline. The
integrated circuit may include dummy wordline tracking circuitry
that is coupled to the dummy wordline between the dummy wordline
driver circuitry and the dummy bitline pulldown circuitry. The
dummy wordline tracking circuitry may have one or more variable
capacitors that are coupled between the dummy wordline and a
variable voltage source.
[0049] Described herein are various implementations of an
integrated circuit. The integrated circuit may include dummy
bitline pulldown circuitry that is coupled to a dummy bitline. The
integrated circuit may include global timing pulse reset circuitry
that is coupled between a dummy wordline and the dummy bitline. The
integrated circuit may include dummy bitline tracking circuitry
that is coupled to the dummy bitline between the dummy bitline
pulldown circuitry and the global timing pulse reset circuitry, The
dummy bitline tracking circuitry may have one or more variable
capacitors that are coupled between the dummy bitline and a
variable voltage source.
[0050] Described herein are various implementations of an
integrated circuit. The integrated circuit may include dummy
wordline driver circuitry that is coupled to a dummy wordline. The
integrated circuit may include dummy bitline pulldown circuitry
that is coupled between a dummy bitline and the dummy wordline. The
integrated circuit may include global timing pulse reset circuitry
that is coupled between the dummy wordline and the dummy bitline.
The integrated circuit may include dummy wordline tracking
circuitry that is coupled to the dummy wordline between the dummy
wordline driver circuitry and the dummy bitline pulldown circuitry.
The dummy wordline tracking circuitry may have at least one first
variable capacitor that is coupled between the dummy wordline and a
first variable voltage source. The integrated circuit may include
dummy bitline tracking circuitry that is coupled to the dummy
bitline between the dummy bitline pulldown circuitry and the global
timing pulse reset circuitry. The dummy bitline tracking circuitry
may have at least one second variable capacitor that is coupled
between the dummy bitline and a second variable voltage source.
[0051] It should be intended that the subject matter of the claims
not be limited to the implementations and illustrations provided
herein, but include modified forms of those implementations
including portions of implementations and combinations of elements
of different implementations in accordance with the claims. It
should be appreciated that in the development of any such
implementation, as in any engineering or design project, numerous
implementation-specific decisions should be made to achieve
developers' specific goals, such as compliance with system-related
and business related constraints, which may vary from one
implementation to another. Moreover, it should be appreciated that
such a development effort may be complex and time consuming, but
would nevertheless be a routine undertaking of design, fabrication,
and manufacture for those of ordinary skill having benefit of this
disclosure.
[0052] Reference has been made in detail to various
implementations, examples of which are illustrated in the
accompanying drawings and figures. In the following detailed
description, numerous specific details are set forth to provide a
thorough understanding of the disclosure provided herein. However,
the disclosure provided herein may be practiced without these
specific details. In some other instances, well-known methods,
procedures, components, circuits and networks have not been
described in detail so as not to unnecessarily obscure details of
the embodiments.
[0053] It should also be understood that, although the terms first,
second, etc. may be used herein to describe various elements, these
elements should not be limited by these terms. These terms are only
used to distinguish one element from another. For example, a first
element could be termed a second element, and, similarly, a second
element could be termed a first element. The first element and the
second element are both elements, respectively, but they are not to
be considered the same element.
[0054] The terminology used in the description of the disclosure
provided herein is for the purpose of describing particular
implementations and is not intended to limit the disclosure
provided herein. As used in the description of the disclosure
provided herein and appended claims, the singular forms "a," "an,"
and "the" are intended to include the plural forms as well, unless
the context clearly indicates otherwise. The term "and/or" as used
herein refers to and encompasses any and all possible combinations
of one or more of the associated listed items. The terms
"includes," "including," "comprises," and/or "comprising," when
used in this specification, specify a presence of stated features,
integers, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components and/or
groups thereof.
[0055] As used herein, the term "if" may be construed to mean
"when" or "upon" or "in response to determining" or "in response to
detecting," depending on the context. Similarly, the phrase "if it
is determined" or "if [a stated condition or event] is detected"
may be construed to mean "upon determining" or "in response to
determining" or "upon detecting [the stated condition or event]" or
"in response to detecting [the stated condition or event],"
depending on the context. The terms "up" and "down"; "upper" and
"lower"; "upwardly" and "downwardly"; "below" and "above"; and
other similar terms indicating relative positions above or below a
given point or element may be used in connection with some
implementations of various technologies described herein.
[0056] While the foregoing is directed to implementations of
various techniques described herein, other and further
implementations may be devised in accordance with the disclosure
herein, which may be determined by the claims that follow.
[0057] Although the subject matter has been described in language
specific to structural features and/or methodological acts, it is
to be understood that the subject matter defined in the appended
claims is not necessarily limited to the specific features or acts
described above. Rather, the specific features and acts described
above are disclosed as example forms of implementing the
claims.
* * * * *