U.S. patent application number 13/494263 was filed with the patent office on 2013-12-12 for low power active filter.
This patent application is currently assigned to Taiwan Semiconductor Manufacturing Co., Ltd.. The applicant listed for this patent is Jun-De Jin, Tzu-Jin Yeh. Invention is credited to Jun-De Jin, Tzu-Jin Yeh.
Application Number | 20130328623 13/494263 |
Document ID | / |
Family ID | 49714794 |
Filed Date | 2013-12-12 |
United States Patent
Application |
20130328623 |
Kind Code |
A1 |
Jin; Jun-De ; et
al. |
December 12, 2013 |
LOW POWER ACTIVE FILTER
Abstract
Some embodiments relate to a band-pass filter arranged in a
ladder-like structure. The band-pass filter includes respective
inductor-capacitor (LC) resonators arranged on respective rungs of
the ladder-like structure. Respective matching circuits are
arranged on a leg of the ladder-like structure between neighboring
rungs.
Inventors: |
Jin; Jun-De; (Hsinchu City,
TW) ; Yeh; Tzu-Jin; (Hsinchu City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Jin; Jun-De
Yeh; Tzu-Jin |
Hsinchu City
Hsinchu City |
|
TW
TW |
|
|
Assignee: |
Taiwan Semiconductor Manufacturing
Co., Ltd.
Hsin-Chu
TW
|
Family ID: |
49714794 |
Appl. No.: |
13/494263 |
Filed: |
June 12, 2012 |
Current U.S.
Class: |
327/557 ;
333/176 |
Current CPC
Class: |
H03H 11/48 20130101;
H03H 7/1758 20130101; H03H 7/0115 20130101 |
Class at
Publication: |
327/557 ;
333/176 |
International
Class: |
H03H 11/04 20060101
H03H011/04; H03H 7/075 20060101 H03H007/075 |
Claims
1. A band-pass filter arranged in a ladder-like structure and
comprising: respective inductor-capacitor (LC) resonators arranged
on respective rungs of the ladder-like structure; and respective
matching circuits arranged on a leg of the ladder-like structure
between respective neighboring rungs; wherein at least one of the
LC resonators is an active inductor comprising: a transistor having
a gate terminal and first and second source/drain terminals; a
first inductor having a first inductor terminal coupled to the
first source/drain terminal; a second inductor having a first
inductor terminal coupled to the gate terminal; and a transmission
line coupled to respective second inductor terminals of the first
and second inductors.
2. The band-pass filter of claim 1, wherein at least two LC
resonators on neighboring rungs comprise at least two active
inductors, respectively.
3-4. (canceled)
5. The band pass filter of claim 1, wherein the transistor, the
first inductor, the second inductor and the transmission line are
all formed on a single integrated circuit die having complementary
metal oxide semiconductor (CMOS) devices thereon.
6. The band pass filter of claim 1, wherein the transistor is
formed on an integrated circuit die having complementary metal
oxide semiconductor (CMOS) devices thereon and wherein the first
inductor, second inductor, and transmission line are formed on an
interposer or integrated passive device chip physically separate
from, but electrically coupled to the integrated circuit die.
7. The band-pass filter of claim 1, further comprising: a first DC
supply voltage coupled to the second source/drain terminal of the
transistor.
8. The band pass filter of claim 7, further comprising: a second DC
supply voltage coupled to the transmission line, the second DC
supply voltage providing a different voltage level then the first
DC supply voltage.
9. The band-pass filter of claim 1, wherein the respective matching
circuits comprise respective capacitors arranged in series along
the leg.
10. A band-pass filter having an input terminal and an output
terminal, the band pass filter comprising: a first
inductor-capacitor (LC) resonator having first and second LC
terminals, the first LC terminal coupled to the input terminal; a
first matching circuit having first and second terminals, the first
terminal coupled to the input terminal; a second LC resonator
having third and fourth LC terminals, the third LC terminal coupled
to the second terminal of the first matching circuit; a second
matching circuit having third and fourth terminals, the third
terminal coupled to the fourth LC terminal; a third
inductor-capacitor (LC) resonator having fifth and sixth LC
terminals, the fifth LC terminal coupled to the fourth terminal of
the second matching circuit; a third matching circuit having fifth
and sixth terminals, the fifth terminal coupled to the fourth
terminal of the second matching circuit; and a fourth LC resonator
having seventh and eight LC terminals, the seventh LC terminal
coupled to the sixth terminal and to the output terminal of the
band-pass filter; wherein at least one of the LC resonators
includes an active inductor comprising: a transistor having a gate
terminal and first and second source/drain terminals; a first
inductor having a first inductor terminal coupled to the first
source/drain terminal; and a second inductor having a first
inductor terminal coupled to the gate terminal.
11. The band-pass filter of claim 10, wherein the second LC
terminal, fourth LC terminal, sixth LC terminal, eighth LC terminal
are coupled to a DC supply voltage.
12. The band-pass filter of claim 10, wherein the second and third
LC resonators comprise second and third active inductors,
respectively.
13. The band-pass filter of claim 12, wherein the second or third
active inductor comprises: a transistor having a gate terminal and
first and second source/drain terminals; a first inductor having a
first inductor terminal coupled to the first source/drain terminal;
a second inductor having a first inductor terminal coupled to the
gate terminal; and a transmission line coupled to respective second
inductor terminals of the first and second inductors.
14. The band-pass filter of claim 13, wherein the transmission line
is coupled to a first DC voltage supply.
15. The band-pass filter of claim 14, wherein the second LC
terminal, fourth LC terminal, sixth LC terminal, eighth LC terminal
are coupled to a second DC supply voltage, which provides a
different voltage level then the first DC supply voltage.
16. The band-pass filter of claim 10, wherein the first, second,
third, and fourth LC resonators comprise respective active
inductors.
17. The band-pass filter of claim 16, wherein the respective active
inductors comprise: a transistor having a gate terminal and first
and second source/drain terminals; a first inductor having a first
inductor terminal coupled to the first source/drain terminal; a
second inductor having a first inductor terminal coupled to the
gate terminal; and a transmission line coupled to respective second
inductor terminals of the first and second inductors.
18. The band pass filter of claim 17, wherein the transistor, the
first inductor, the second inductor and the transmission line are
all formed on a single integrated circuit die having complementary
metal oxide semiconductor (CMOS) devices thereon.
19. The band pass filter of claim 17, wherein the transistor is
formed on an integrated circuit die having complementary metal
oxide semiconductor (CMOS) devices thereon and wherein the first
inductor, second inductor, and transmission line are formed on an
interposer chip physically separate from, but electrically coupled
to the integrated circuit die.
20. The band pass filter of claim 17, wherein the transistor is
formed on an integrated circuit die having complementary metal
oxide semiconductor (CMOS) devices thereon and wherein the first
inductor, second inductor, and transmission line are formed on an
integrated passive device chip physically separate from, but
electrically coupled to the integrated circuit die.
Description
BACKGROUND
[0001] Band pass filters are used extensively in mobile
communications systems, such as cellular phones and local area
networks (LANs) for example, to suppress unwanted signals and to
provide wanted signals with enough gain and at a sufficiently
narrow frequency range to meet desired specifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] FIG. 1A shows a conventional band-pass filter having an
input terminal and an output terminal.
[0003] FIG. 1B shows an input signals for FIG. 1A's band-pass
filter.
[0004] FIG. 1C shows an output signal for FIG. 1A's band-pass
filter.
[0005] FIG. 2 shows a band-pass filter in accordance with some
embodiments.
[0006] FIG. 3 shows an active inductor that can be used in FIG. 2's
band-pass filter.
[0007] FIG. 4 is a chart illustrating reduced power consumption of
an exemplary band-pass filter relative to several prior art
band-pass filters.
[0008] FIG. 5 shows a band-pass filter in accordance with some
embodiments.
[0009] FIG. 6 shows a band-pass filter in accordance with some
embodiments.
[0010] FIGS. 7A-7C illustrate three different options for packaging
band-pass filters in accordance with some embodiments.
DETAILED DESCRIPTION
[0011] The present disclosure will now be described with reference
to the drawings wherein like reference numerals are used to refer
to like elements throughout, and wherein the illustrated structures
are not necessarily drawn to scale. It will be appreciated that
this detailed description and the corresponding figures do not
limit the scope of the present disclosure in any way, and that the
detailed description and figures merely provide a few examples to
illustrate some ways in which the inventive concepts can manifest
themselves.
[0012] FIG. 1 illustrates the operation of a conventional band pass
filter (BPF) 100 having an input terminal 102 and an output
terminal 104. During operation, the BPF 100 receives an input
signal at the input terminal 102. As shown in FIG. 1B, input signal
105 can include a wide range of frequency components (e.g., wanted
frequency components 106 and un-wanted frequency components 108).
In a wireless communication device, such as a cellular phone for
example, the wanted frequency components 106 could correspond to
data encoded on a modulated carrier wave within a wanted frequency
range, and the un-wanted frequency components (e.g., noise) could
be other signals in the unwanted frequency range 108. To isolate
the wanted frequency components 106, the band-pass filter 100 is
structured to attenuate input frequencies which are less than lower
cut-off frequency, f.sub.L 110 and which are greater than cut-off
frequency, f.sub.H 112. This produces an output signal 114 (FIG.
1C) in the wanted frequency range, which can be for example
centered about a center frequency f.sub.0.
[0013] Although many types of band-pass filters are known,
conventional band-pass filters consume a significant amount of
power due to the fact they often include large capacitors,
inductors, and/or transmission lines. Unfortunately, in today's era
of portable electronic devices that are battery-powered, this
significant power consumption reduces the operational lifetime of a
portable electronic device from one charging to the next.
Accordingly, the present disclosure relates to techniques for
providing ultra low power band-pass filters. These ultra-low power
band-pass filters help to extend the useful lifetime of portable
devices to help end users get more productivity from their portable
devices.
[0014] FIG. 2 illustrates a schematic for a low power band-pass
filter 200 in accordance with some embodiments. The band-pass
filter 200 has a ladder-like structure made up of legs 202, 204 and
rungs 206-212. Along each rung is an inductor-capacitor (LC)
resonator that can, but does not necessarily, include an active
inductor. Thus, a first LC resonator 214 is positioned on first
rung 206, a second LC resonator 216 is positioned on second rung
208, a third LC resonator 218 is positioned on third rung 210, and
fourth LC resonator 220 is positioned on fourth rung 212. Matching
circuits 222, 224, 226 are disposed along first leg 202 between
neighboring rungs. For example, a first matching circuit 222 is
arranged on the first leg 202 between the first and second rungs
206, 208. The second leg 204 is coupled to a DC supply voltage,
such as ground, for example. It will be appreciated that because
FIG. 2 illustrates a schematic view rather than a layout view, and
the actual layout may appear ladder-like but it may also appear to
be non-ladder like because of interconnect routing and component
placement.
[0015] One or more of the LC resonators 216-220 include an active
inductor, which helps to reduce power consumption significantly
relative to previous low-pass band pass filters. For example, in
some embodiments, the second and third LC resonators 216, 218 each
include an active inductor; while in other embodiments, the first,
second, third and fourth resonators 214-220 include respective
active inductors. These active inductors limit current leakage
(e.g., current leaked to ground), and thereby limit power
consumption during operation of the BPF 200.
[0016] FIG. 3 shows an example of an active inductor 300 that can
help limit power consumption in accordance with some embodiments.
The active inductor 300 includes a pair of coupled inductors 302,
304, which are in close proximity such that current in one inductor
induces a voltage in the other inductor. The dot (e.g., 302a or
304a)--or current input terminal--symbolizes the side of the
inductor from where the current is supposed to enter that inductor.
Thus, in FIG. 3, the first inductor 302 has a current input
terminal 302a coupled to the drain of transistor 306 and has a
current output terminal 302b coupled to transmission line 308. The
second inductor 304 has a current input terminal 304a coupled to
transmission line 308, and has a current output terminal 304b
coupled to the gate of transistor 306. The inductance values of the
first and second inductors 302, 304 (along with length and width of
transistor 306) are set to predetermined values during the design
phase to help establish a passband corresponding to a wanted
frequency range.
[0017] FIG. 4 shows a chart 400 illustrating several performance
characteristics of one BPF embodiment 402 in accordance with this
disclosure compared with several prior art approaches. As shown,
the BPF embodiment 402 has a DC power consumption 404 (e.g, 0.1 mW)
that is less than 1% of the power consumptions for each of the
other prior art circuits. As for the other performance
characteristics, the BPF embodiment 402 is similar in many regards.
Although FIG. 4 is not meant to be representative of all power
consumptions for all BPFs in any way, it does tend to show that the
proposed implementations can provide significant power savings
compared to some prior art approaches.
[0018] FIG. 5 depicts another embodiment of a band-pass filter 500
having an input terminal 502 and an output terminal 504. Although
the input and output terminals are referred to as "input" and
"output", these terminals may be largely interchangeable in some
embodiments due to symmetries of the circuitry involved.
[0019] Like FIG. 2's embodiment, the band pass filter 500 is
arranged in a ladder-like structure including legs (e.g., 506, 508)
and rungs (e.g., 510-516). On first and fourth rungs 510, 516,
respectively, first and fourth inductor-capacitor (LC) resonators
518, 520, respectively are arranged. On second and third rungs 512,
514, respectively, second and third inductor capacitors 530, 532
are arranged. A DC supply voltage 554 biases second and third LC
resonators 530, 532.
[0020] The first LC resonator 518 is made up of passive inductor
522 and passive capacitor 524 and has first and second LC terminals
518a, 518b. The fourth LC resonator 520 is made up of passive
inductor 526 and passive capacitor 528 and also has seventh and
eighth LC terminals 520a, 520b.
[0021] The second LC resonator 530 is made up of active inductor
534 and passive capacitor 536 and has third and fourth LC terminals
530a, 530b. The third LC resonator 532 is also made up of an active
inductor 538 and passive capacitor 540 and has fifth and sixth LC
terminals 532a, 532b.
[0022] First, second, and third matching circuits 542, 544, 546,
respectively are arranged between neighboring rungs. The first
matching circuit 542, which has first and second matching circuit
terminals 542a, 542b with capacitor 548 therebetween, has its first
matching circuit terminal 542a coupled to the BPF input terminal
502 and second matching circuit terminal 542b. The second matching
circuit 544 has third and fourth terminals 544a, 544b with
capacitor 550 therebetween. A third matching circuit 546 has fifth
and sixth terminals 546a, 546b with capacitor 552 therebetween.
[0023] FIG. 6 shows another embodiment of a BPF 600 where the
passive inductors in the first and fourth LC resonators previously
illustrated in FIG. 5 are replaced with active inductors. Thus,
because the first and fourth LC resonators 602, 604 in FIG. 6 have
active inductors rather than passive inductors, FIG. 6's BPF can
provide even lower power consumption in some contexts, relative to
BPF 500 in FIG. 5.
[0024] FIGS. 7A-7C show three different embodiments for packaging
BPFs in accordance with this disclosure. As shown in FIG. 7A, in
some embodiments, a BPF can be included on an integrated circuit
die 700 with complementary metal oxide semiconductor (CMOS)
devices. Thus, the active inductors, capacitors, transmission
lines, and transistors of the previous BPF embodiments are all
formed on the die, and are coupled to external circuits via solder
bumps 702 or other conductive leads (e.g., wires or landing
pads).
[0025] FIG. 7B shows another embodiment where active devices (e.g.,
transistors) are formed on a CMOS die 704; while passive devices,
including inductors, capacitors, and transmission lines are formed
on an integrated passive device (IPD) chip 706. In this
implementation, the CMOS die 704 is a semiconductor substrate in
which active areas are implanted and alternating layers of
insulating and conducting layers are formed to form the active
devices. The IPD chip 706, in contrast, although still a
semiconductor substrate, can be low-conductivity silicon and can
include thick copper interconnect structures. Thus, inductors,
capacitors, transmission lines, and transistors of the previous BPF
embodiments are formed on the IPD 706, and are coupled to
transistors formed on CMOS die 704 via solder bumps 708 or other
conductive leads (e.g., wires or landing pads).
[0026] FIG. 7C shows another embodiment where active devices (e.g.,
transistors) are formed on a CMOS die 710; while passive devices,
including inductors, capacitors, and transmission lines are formed
on an interposer chip 712. In this implementation, the CMOS die is
a semiconductor substrate in which active areas are implanted and
alternating layers of insulating and conducting layers are formed
to form the active devices. The interposer chip, in contrast,
although still a semiconductor substrate, can be high-conductivity
silicon and can include CMOS-type interconnect. Thus, inductors,
capacitors, transmission lines, and transistors of the previous BPF
embodiments are formed on the interposer chip 712, and are coupled
to transistors formed on CMOS die 710 via solder bumps 714 or other
conductive leads (e.g., wires or landing pads). Although FIGS. 7B
and 7C show only one IPD and only one interposer, respectively, it
will be appreciated that IPD and interposer chips can be "stacked"
in some embodiments.
[0027] Some embodiments relate to a band-pass filter arranged in a
ladder-like structure. The band-pass filter includes respective
inductor-capacitor (LC) resonators arranged on respective rungs of
the ladder-like structure. Respective matching circuits are
arranged on a leg of the ladder-like structure between neighboring
rungs.
[0028] Some embodiments relate to a band-pass filter (BPF) having
an input terminal and output terminal. In this BPF, a first
inductor-capacitor (LC) resonator having first and second LC
terminals has its first LC terminal coupled to the input terminal.
A first matching circuit has first and second terminals, with the
first terminal coupled to the input terminal. A second LC resonator
has third and fourth LC terminals, with the third LC terminal
coupled to the second terminal of the first matching circuit. A
second matching circuit has third and fourth terminals, where the
third terminal is coupled to the fourth LC terminal. A third
inductor-capacitor (LC) resonator has fifth and sixth LC terminals,
where the fifth. LC terminal is coupled to the fourth terminal of
the second matching circuit. A third matching circuit has fifth and
sixth terminals, where the fifth terminal is coupled to the fourth
terminal of the second matching circuit. A fourth LC resonator has
seventh and eight LC terminals, where the seventh LC terminal is
coupled to the sixth matching terminal and to the output terminal
of the band-pass filter.
[0029] Although the disclosure has been shown and described with
respect to a certain aspect or various aspects, equivalent
alterations and modifications will occur to others of ordinary
skill in the art upon reading and understanding this specification
and the annexed drawings. For example, it will be appreciated that
the terms "first", "second", "third" and the like do not imply any
spatial or temporal relationship therebetween, but rather are just
generic identifiers. Further, these terms are interchangeable in
this disclosure. For example, although one portion of this
disclosure may refer to a "first" feature and a "second" feature,
because first and second are merely generic identifiers, they
features may also be referred to as a "second" feature and a
"first" feature respectively. Further, the terms "couple",
"couples", "coupled" and the like include direct and indirect
coupling. For example, if element A is "coupled to" element B,
element A can be in direct contact with element B; however it is
also possible that element "C" is arranged between elements A and B
so long as there is still an operable coupling between A and B. In
particular regard to the various functions performed by the above
described components (assemblies, devices, circuits, etc.), the
terms (including a reference to a "means") used to describe such
components are intended to correspond, unless otherwise indicated,
to any component which performs the specified function of the
described component (i.e., that is functionally equivalent), even
though not structurally equivalent to the disclosed structure which
performs the function in the herein illustrated exemplary
embodiments of the disclosure. In addition, while a particular
feature of the disclosure may have been disclosed with respect to
only one of several aspects of the disclosure, such feature may be
combined with one or more other features of the other aspects as
may be desired and advantageous for any given or particular
application. Furthermore, to the extent that the terms "including",
"includes", "having", "has", "with", or variants thereof are used
in either the detailed description and the claims, such terms are
intended to be inclusive in a manner similar to the term
"comprising".
* * * * *