U.S. patent application number 16/251036 was filed with the patent office on 2020-04-16 for transconductance controlling circuit.
The applicant listed for this patent is Industrial Technology Research Institute. Invention is credited to Tai-Hsing LEE, Jie ZHANG.
Application Number | 20200119691 16/251036 |
Document ID | / |
Family ID | 70160784 |
Filed Date | 2020-04-16 |
United States Patent
Application |
20200119691 |
Kind Code |
A1 |
LEE; Tai-Hsing ; et
al. |
April 16, 2020 |
TRANSCONDUCTANCE CONTROLLING CIRCUIT
Abstract
A transconductance controlling circuit is provided. The
transconductance controlling circuit includes a resonance circuit,
a negative-resistance unit-circuit and a transconductance boosting
circuit. The resonance circuit generates an oscillation signal. The
negative-resistance unit-circuit is coupled to a resonance circuit
and includes a first transistor and a second transistor. The
transconductance boosting circuit is coupled to the
negative-resistance unit-circuit and includes a third transistor
and a fourth transistor. A first drain of the first transistor is
coupled to a third drain of the third transistor, a first gate of
the first transistor is coupled to a third gate of the third
transistor, the first gate of the first transistor is coupled to a
second drain of the second transistor, and a first base of the
first transistor is coupled to a fourth base of the fourth
transistor and to a fourth source of the fourth transistor.
Inventors: |
LEE; Tai-Hsing; (Hsinchu
City, TW) ; ZHANG; Jie; (New Taipei City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Industrial Technology Research Institute |
Hsinchu |
|
TW |
|
|
Family ID: |
70160784 |
Appl. No.: |
16/251036 |
Filed: |
January 17, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H03B 5/124 20130101;
H03B 5/1212 20130101; H03B 5/30 20130101; H03B 5/1215 20130101;
H03B 5/1278 20130101; H03B 5/1228 20130101; H03B 2200/009 20130101;
H03B 5/1271 20130101 |
International
Class: |
H03B 5/12 20060101
H03B005/12; H03B 5/30 20060101 H03B005/30 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 16, 2018 |
TW |
107136318 |
Claims
1. A transconductance controlling circuit, comprising: a resonance
circuit, generating an oscillation signal according to an input
voltage; a negative-resistance unit-circuit, coupled to a resonance
circuit and comprising a first transistor and a second transistor;
and a transconductance boosting circuit, coupled to the
negative-resistance unit-circuit and comprising a third transistor
and a fourth transistor, wherein a first drain of the first
transistor is coupled to a third drain of the third transistor, a
first gate of the first transistor is coupled to a third gate of
the third transistor, the first gate of the first transistor is
coupled to a second drain of the second transistor, and a first
base of the first transistor is coupled to a fourth base of the
fourth transistor and to a fourth source of the fourth transistor,
and wherein the second drain of the second transistor is coupled to
a fourth drain of the fourth transistor, a second gate of the
second transistor is coupled to a fourth gate of the fourth
transistor, the second gate of the second transistor is coupled to
the first drain of the first transistor, and a second base of the
second transistor is coupled to a third base of the third
transistor and to a third source of the third transistor.
2. The transconductance controlling circuit of claim 1, wherein the
resonance circuit is coupled to a drain power source, the first
drain and the second drain.
3. The transconductance controlling circuit of claim 2, wherein the
resonance circuit comprises a first inductor, a second inductor, a
first capacitor, and a second capacitor, wherein the first inductor
and the second inductor are coupled to the drain power source and
the first capacitor and the second capacitor are coupled to the
input voltage.
4. The transconductance controlling circuit of claim 1, wherein the
transconductance boosting circuit further comprises a first
resistor and a second resistor, wherein the third source of the
third transistor is coupled to the first resistor, and the fourth
source of the fourth transistor is coupled to the second resistor,
and the first resistor and the second resistor are coupled to a
ground.
5. The transconductance controlling circuit of claim 1, wherein the
transconductance boosting circuit further comprises a fifth
transistor and a sixth transistor, wherein the third source of the
third transistor is coupled to a fifth drain and a fifth gate of
the fifth transistor, and the fourth source of the fourth
transistor is coupled to a sixth drain and a sixth gate of the
sixth transistor, and a fifth source of the fifth transistor and a
sixth source of the sixth transistor are coupled to a ground.
6. The transconductance controlling circuit of claim 1, further
comprising: a first amplifier circuit, coupled to the resonance
circuit, and comprising a seventh transistor; and a second
amplifier circuit, coupled to the resonance circuit, and comprising
an eighth transistor.
7. The wideband transimpedance amplifier circuit of claim 6,
further comprising: a bias current controlling circuit, coupled to
the negative-resistance unit-circuit and comprising a ninth
transistor and a third resistor.
8. A transconductance controlling circuit, comprising: a
voltage-controlled oscillator, generating an oscillation signal
according to an input voltage and comprising a negative-resistance
unit-circuit, wherein the negative-resistance unit-circuit
comprises a first transistor and a second transistor; and a
transconductance boosting circuit, coupled to the
negative-resistance unit-circuit and comprising a third transistor
and a fourth transistor, wherein a first drain of the first
transistor is coupled to a third drain of the third transistor, a
first gate of the first transistor is coupled to a third gate of
the third transistor, the first gate of the first transistor is
coupled to a second drain of the second transistor, and a first
base of the first transistor is coupled to a fourth base of the
fourth transistor and to a fourth source of the fourth transistor,
and wherein the second drain of the second transistor is coupled to
a fourth drain of the fourth transistor, a second gate of the
second transistor is coupled to a fourth gate of the fourth
transistor, the second gate of the second transistor is coupled to
the first drain of the first transistor, and a second base of the
second transistor is coupled to a third base of the third
transistor and to a third source of the third transistor.
9. The transconductance controlling circuit of claim 8, wherein the
voltage-controlled oscillator further comprises a resonance
circuit, and the resonance circuit generates an oscillation signal
according to an input voltage.
10. The transconductance controlling circuit of claim 9, wherein
the resonance circuit is coupled to a drain power source, the first
drain and the second drain.
11. The transconductance controlling circuit of claim 10, wherein
the resonance circuit comprises a first inductor, a second
inductor, a first capacitor, and a second capacitor, wherein the
first inductor and the second inductor are coupled to the drain
power source and the first capacitor and the second capacitor are
coupled to the input voltage.
12. The transconductance controlling circuit of claim 8, wherein
the transconductance boosting circuit further comprises a first
resistor and a second resistor, wherein the third source of the
third transistor is coupled to the first resistor, and the fourth
source of the fourth transistor is coupled to the second resistor,
and the first resistor and the second resistor are coupled to a
ground.
13. The transconductance controlling circuit of claim 8, wherein
the transconductance boosting circuit further comprises a fifth
transistor and a sixth transistor, wherein the third source of the
third transistor is coupled to a fifth drain and a fifth gate of
the fifth transistor, and the fourth source of the fourth
transistor is coupled to a sixth drain and a sixth gate of the
sixth transistor, and a fifth source of the fifth transistor and a
sixth source of the sixth transistor are coupled to a ground.
14. The transconductance controlling circuit of claim 8, further
comprising: a first amplifier circuit, coupled to the resonance
circuit, and comprising a seventh transistor; and a second
amplifier circuit, coupled to the resonance circuit, and comprising
an eighth transistor.
15. The wideband transimpedance amplifier circuit of claim 8,
further comprising: a bias current controlling circuit, coupled to
the negative-resistance unit-circuit and comprising a ninth
transistor and a third resistor.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This Application claims priority of Taiwan Patent
Application No. 107136318 filed on Oct. 16, 2018, the entirety of
which is incorporated by reference herein.
TECHNICAL FIELD
[0002] The disclosure generally relates to eliminate the phase
noise in a voltage-controlled oscillator (VCO), and relates to a
transconductance circuit.
BACKGROUND
[0003] In the front-end of the radio frequency (RF) circuit, the
VCO is utilized to provide a precise local oscillation signal to
the mixer to transform the signal into an RF signal or transform
the signal to an intermediate frequency (IF) signal.
[0004] The phase noise may have a strong effect on the output
signal of the VCO. Therefore, if the phase noise is reduced, the
burden on the next stage circuit behind the VCO will be decreased.
In the prior art, there are two methods to reduce the phase noise
of the VCO. One method is by increasing the Q value (quality
parameter of the inductor) of the inductor and the other method is
by increasing the output power. However, in the method for
increasing the Q value of the general transformer inductor, the
larger area may need to be configured for the inductor. In
addition, the method for increasing the output power may use more
power.
SUMMARY
[0005] An embodiment of the disclosure provides a transconductance
controlling circuit. The transconductance controlling circuit
comprises a resonance circuit, a negative-resistance unit-circuit
and a transconductance boosting circuit. The resonance circuit
generates an oscillation signal according to an input voltage. The
negative-resistance unit-circuit is coupled to a resonance circuit
and comprises a first transistor and a second transistor. The
transconductance boosting circuit is coupled to the
negative-resistance unit-circuit and comprises a third transistor
and a fourth transistor. A first drain of the first transistor is
coupled to a third drain of the third transistor, a first gate of
the first transistor is coupled to a third gate of the third
transistor, the first gate of the first transistor is coupled to a
second drain of the second transistor, and a first base of the
first transistor is coupled to a fourth base of the fourth
transistor and to a fourth source of the fourth transistor. In
addition, the second drain of the second transistor is coupled to a
fourth drain of the fourth transistor, a second gate of the second
transistor is coupled to a fourth gate of the fourth transistor,
the second gate of the second transistor is coupled to the first
drain of the first transistor, and a second base of the second
transistor is coupled to a third base of the third transistor and
to a third source of the third transistor.
[0006] An embodiment of the disclosure provides a transconductance
controlling circuit. The transconductance controlling circuit
comprises a voltage-controlled oscillator and a transconductance
boosting circuit. The voltage-controlled oscillator generates an
oscillation signal according to an input voltage and comprising a
negative-resistance unit-circuit, wherein the negative-resistance
unit-circuit comprises a first transistor and a second transistor.
The transconductance boosting circuit is coupled to the
negative-resistance unit-circuit and comprising a third transistor
and a fourth transistor. A first drain of the first transistor is
coupled to a third drain of the third transistor, a first gate of
the first transistor is coupled to a third gate of the third
transistor, the first gate of the first transistor is coupled to a
second drain of the second transistor, and a first base of the
first transistor is coupled to a fourth base of the fourth
transistor and to a fourth source of the fourth transistor. The
second drain of the second transistor is coupled to a fourth drain
of the fourth transistor, a second gate of the second transistor is
coupled to a fourth gate of the fourth transistor, the second gate
of the second transistor is coupled to the first drain of the first
transistor, and a second base of the second transistor is coupled
to a third base of the third transistor and to a third source of
the third transistor.
[0007] Other aspects and features of the disclosure will become
apparent to those with ordinary skill in the art upon review of the
following descriptions of specific embodiments of the
transconductance controlling circuits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The disclosure will become more fully understood by
referring to the following detailed description with reference to
the accompanying drawings, wherein:
[0009] FIG. 1 is a block diagram of a transconductance (g.sub.m)
controlling circuit according to an embodiment of the
disclosure;
[0010] FIG. 2 is a circuit diagram of a transconductance (g.sub.m)
controlling circuit according to an embodiment of the disclosure;
and
[0011] FIG. 3 is a circuit diagram of a transconductance (g.sub.m)
controlling circuit according to another embodiment of the
disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0012] The following description is of the best-contemplated mode
of carrying out the disclosure. This description is made for the
purpose of illustrating the general principles of the disclosure
and should not be taken in a limiting sense. The scope of the
disclosure is determined by reference to the appended claims.
[0013] Transconductance controlling circuits used for eliminating
phase noise in a voltage-controlled oscillator (VCO) by configuring
a transconductance boosting circuit are provided to overcome the
problems described above.
[0014] FIG. 1 is a block diagram of a transconductance (g.sub.m)
controlling circuit according to an embodiment of the disclosure.
As shown in FIG. 1, the transconductance controlling circuit 100
may comprise a resonance circuit (or LC circuit) 110, a
negative-resistance unit-circuit 120, a transconductance boosting
circuit 130, an amplifier circuit 140, and bias current controlling
circuit 150. In order to clarify the concept of the disclosure,
FIG. 1 presents a simplified block diagram in which the elements
relevant to the disclosure are shown. However, the disclosure
should not be limited to what is shown in FIG. 1. The
transconductance controlling circuit 100 may also comprise other
elements.
[0015] As shown FIG. 1, the resonance circuit 110 may be coupled to
a drain power source Vdd, negative-resistance unit-circuit 120 and
amplifier circuit 140. The resonance circuit 110 may generate an
oscillation signal according to an input voltage Vt. The
negative-resistance unit-circuit 120 may be utilized to cancel the
effect of parasitic resistance of the resonance circuit 110 to
decrease the loss of the oscillation signal generated by the
resonance circuit 110. The amplifier circuit 140 is utilized to
amplify the oscillation signal generated by the resonance circuit
110 and output the amplified oscillation signal. According to an
embodiment of the invention, the resonance circuit 110 and the
negative-resistance unit-circuit 120 may be combined to be a
voltage-controlled oscillator (VCO).
[0016] In addition, as shown in FIG. 1, the transconductance
boosting circuit 130 may be coupled to the negative-resistance
unit-circuit 120. The transconductance boosting circuit 130 may
boost the transconductance (g.sub.m) of the transistors of the
negative-resistance unit-circuit 120. The bias current controlling
circuit 150 may be coupled to the negative-resistance unit-circuit
120. The bias current controlling circuit 150 may control the
current flowing through the negative-resistance unit-circuit
120.
[0017] FIG. 2 is a circuit diagram of a transconductance (g.sub.m)
controlling circuit according to an embodiment of the disclosure.
The circuit diagram of FIG. 2 is for illustrating the embodiments
of the disclosure, but the disclosure should not be limited to what
is shown in FIG. 2.
[0018] As shown in FIG. 2, the resonance circuit 110 may comprise a
first inductor L1, a second inductor L2, a first capacitor C1 and a
second capacitor C2. In an embodiment, the first inductor L1 and
the second inductor L2 may be coupled to the drain power source
Vdd, and the first capacitor C1 and the second capacitor C2 may be
coupled to the input voltage Vt. The capacitance value of the first
capacitor C1 and the second capacitor C2 may be adjusted according
to the input voltage Vt to generate the oscillation signals with
different frequencies. The first capacitor C1 may be coupled to the
amplifier circuit 140 through a third capacitor C3 and the second
capacitor may be coupled to the amplifier circuit 140 through a
fourth capacitor C4.
[0019] As shown in FIG. 2, the negative-resistance unit-circuit 120
may comprise a first transistor M1 and a second transistor M2. A
first drain of the first transistor M1 and a second drain of the
second transistor M2 may be coupled to the resonance circuit 110 to
obtain the drain power source Vdd. In the embodiments of the
invention, the transconductance (g.sub.m) may be increased by
adjusting the base voltage of the first transistor M1 and the
second transistor M2. Details for increasing the transconductance
(g.sub.m) are illustrated below.
[0020] According to an embodiment of the invention, the
transconductance boosting circuit 130 may comprise a third
transistor M3, a fourth transistor M4, a first resistor R1 and a
second resistor R2. In addition, the first resistor R1 and the
second resistor R2 are coupled to a ground. As shown in FIG. 2, the
first drain of the first transistor M1 may be coupled to a third
train of the third drain. A first gate of the first transistor M1
may be coupled to a third gate of the third transistor M3. The
first gate of the first transistor N1 may be coupled to a second
train of the second transistor M2. A first base of the first
transistor M1 may be coupled to a fourth base of the fourth
transistor M4 and to a fourth source of the fourth transistor M4.
The second drain of the second transistor M2 may be coupled to a
fourth drain of the fourth transistor M4. A second gate of the
second transistor M2 may be coupled to a fourth gate of the fourth
transistor M4. The second gate of the second transistor M2 may be
coupled to the first drain of the first transistor M1. The second
base of the second transistor M2 may be coupled to the third base
of the third transistor M3 and to a third drain of the third
transistor M3. The first source of the transistor M1 and the second
source of the second transistor M2 may be coupled to the bias
current controlling circuit 150.
[0021] In an embodiment of the invention, when the oscillation
signal received by the first transistor M1 is negative level (i.e.
the oscillation signal received by the second transistor M2 is
positive level), the fourth transistor M4 may adjust the base
voltage of the first transistor M1 to boost the transconductance
(g.sub.m) of the first transistor M1. In an embodiment of the
invention, when the oscillation signal received by the second
transistor M2 is negative level (i.e. the oscillation signal
received by the first transistor M1 is positive level), the third
transistor M3 may adjust the base voltage of the second transistor
M2 to boost the transconductance (g.sub.m) of the second transistor
M2. When the transconductance (g.sub.m) of the first transistor M1
or the second transistor M2 of the negative-resistance unit-circuit
120 is boosted, the Q values (i.e. the quality parameter of the
inductor) of the inductors (i.e. the first inductor L1 and the
second inductor L2) of the resonance circuit 110 will be increased
to ensure the phase noise of the resonance circuit 110 can be
reduced. Details are illustrated by the formulas related to the Q
value Q.sub.L of the inductor, the total transconductance G.sub.T,
and the transconductance g.sub.m below.
[0022] According to the formula of the Q value Q.sub.L of the
inductor (i.e. the quality parameter of the inductor):
Q L = 1 G T c T L , ##EQU00001##
wherein G.sub.T is the total transconductance, C.sub.T is the total
parasitic resistance, and L is the inductor value, we can know that
when the total transconductance G.sub.T of the VCO (i.e. the
resonance circuit 100 and the negative-resistance unit-circuit 120)
decreases, the Q value Q.sub.L of the inductor of the resonance
circuit 110 will be increased.
[0023] Furthermore, according to the formula of the total
transconductance G.sub.T:
G T = G L + G A = R S ( .omega. L ) 2 - 2 g m , ##EQU00002##
wherein G.sub.L is the electrical conductivity of the inductor, and
G.sub.A is the transconductance of the transistor, we can know that
when the transconductance g.sub.m of the first transistor M1 or the
second transistor M2 of the negative-resistance unit-circuit 120 is
boosted, the total transconductance G.sub.T of the VCO (i.e. the
resonance circuit 100 and the negative-resistance unit-circuit 120)
will be decreased.
[0024] Furthermore, according to the formula of the
transconductance g.sub.m:
g m = 2 2 .PHI. F + V SB r .times. g mb , ##EQU00003##
wherein .phi..sub.F is the Fermi level coefficient, V.sub.SB is the
voltage between the source and the base of the transistor, r is
body effect coefficient and g.sub.mb is the current source model
between the drain and the source of the transistor, we can know
that when the voltage V.sub.SB between the source and the base of
the first the transistor M1 or the second transistor M2 of the
negative-resistance unit-circuit 120 increases, the
transconductance g.sub.m of the first transistor M1 or the second
transistor M2 will be boosted.
[0025] Therefore, according to all the above formulas, it can be
derived that when the third resistor M3 of the transconductance
boosting circuit 130 boosts the base voltage of the second
transistor M2 (i.e. increase the voltage V.sub.SB between the
source and the base of the second transistor M2), the
transconductance g.sub.m of the second transistor M2 will be
boosted, and when the fourth resistor M4 of the transconductance
boosting circuit 130 boosts the base voltage of the first
transistor M1 (i.e. increase the voltage V.sub.SB between the
source and the base of the first transistor M1), the
transconductance g.sub.m of first transistor M1 will be boosted.
When the transconductance g.sub.m of the first transistor M1 or the
second transistor M2 of the negative-resistance unit-circuit 120 is
boosted, the Q value Q.sub.L of the inductor of the resonance
circuit 110 will be increased. Therefore, the transconductance
boosting circuit 130 may achieve the goal of reducing the phase
noise of the VCO (i.e. the resonance circuit 100 and the
negative-resistance unit-circuit 120).
[0026] Back to FIG. 2, the amplifier circuit 140 may comprise a
first amplifier circuit 141 and a second amplifier circuit 142. The
first amplifier circuit 141 may comprise a seventh transistor M7
and output the amplified oscillation Vop with positive level. The
second amplifier circuit 142 may comprise an eighth transistor M8
and output the amplified oscillation Von with negative level. The
seventh gate of the seventh transistor M7 and the eighth gate of
the eighth transistor M8 may be coupled to the amplifier power
source Vog respectively through the fourth resistor R4 and fifth
transistor R5. In addition, the seventh gate of the seventh
transistor M7 may be coupled to the first inductor L1 and the first
capacitor C1 through the third capacitor C3, and the eighth gate of
the eighth transistor M8 may be coupled to the second inductor L2
and the second capacitor C2 through the fourth capacitor C4. The
seventh source of the seventh transistor M7 and the eighth source
of the eighth transistor M8 may be coupled to a ground.
[0027] As shown in FIG. 2, the bias current controlling circuit 150
may comprise a ninth transistor M9 and a third resistor R3. The
ninth drain of the ninth transistor M9 may be coupled to the first
source of the first transistor M1 of the negative-resistance
unit-circuit 120 and to the second source of the second transistor
M2 of the negative-resistance unit-circuit 120. The ninth source of
the ninth transistor M9 may be coupled to a ground. The ninth gate
of the ninth transistor M9 may be coupled to a adjusting voltage
Vsg through the third resistor R3 and the adjusting voltage Vsg may
be coupled to a ground. The adjusting voltage Vsg is utilized to
control the current flowing through the negative-resistance
unit-circuit 120.
[0028] FIG. 3 is a circuit diagram of a transconductance (g.sub.m)
controlling circuit according to another embodiment of the
disclosure. The circuit diagram of FIG. 3 is for illustrating the
embodiments of the disclosure, but the disclosure should not be
limited to what is shown in FIG. 3.
[0029] As shown in FIG. 3, unlike FIG. 2, the transconductance
boosting circuit 130 may comprise a third transistor M3, a fourth
transistor M4, a fifth transistor M5, and a sixth transistor M6.
The fifth drain and the fifth gate of the fifth transistor M5 may
be coupled to the third source of the third transistor M3. The
sixth drain and the sixth gate of the sixth transistor M6 may be
coupled to the fourth source of the fourth transistor M4. In
addition, the fifth source of the fifth transistor M5 and sixth
source of the sixth transistor M6 may be coupled to ground. The
operations of the other elements of FIG. 3 are the same as FIG. 2,
therefore, further details are not illustrated herein.
[0030] According to the transconductance controlling circuit
provided in the embodiments of the invention, a transconductance
boosting circuit is provided to boost the transconductance g.sub.m
of the resistors of the negative-resistance unit-circuit to ensure
the Q value Q.sub.L of the inductor of the resonance circuit can be
increased. Therefore, according the transconductance controlling
circuit provided in the embodiments of the invention, the phase
noise of the VCO (i.e. the resonance circuit and the
negative-resistance unit-circuit) can be reduced.
[0031] The wideband transimpedance amplifier circuit of the
disclosure has a common-gate transistor that is taken as an input
impedance, and the input impedance is adjusted adaptively.
[0032] Use of ordinal terms such as "first", "second", "third",
etc., in the disclosure and claims is for description. It does not
by itself connote any order relationship. Reference throughout this
specification to "one embodiment" or "an embodiment" means that a
particular feature, structure, or characteristic described in
connection with the embodiment is included in at least one
embodiment of the disclosure, but does not denote that they are
present in every embodiment. Thus, the appearance of the phrases
"in one embodiment" or "in an embodiment" in various places
throughout this specification are not necessarily referring to the
same embodiment of the disclosure.
[0033] The above paragraphs describe many aspects of the
disclosure. Obviously, the teaching of the disclosure can be
accomplished by many methods, and any specific configurations or
functions in the disclosed embodiments present a representative
condition. Those who are skilled in this technology will understand
that all of the disclosed aspects in the disclosure can be applied
independently or be incorporated.
[0034] While the disclosure has been described by way of example
and in terms of preferred embodiment, it should be understood that
the disclosure is not limited thereto. Those who are skilled in
this technology can still make various alterations and
modifications without departing from the scope and spirit of this
disclosure. Therefore, the scope of the present disclosure shall be
defined and protected by the following claims and their
equivalents.
* * * * *