U.S. patent application number 16/453989 was filed with the patent office on 2019-10-17 for device and method for generating duty cycle.
The applicant listed for this patent is GLOBAL UNICHIP CORPORATION, TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.. Invention is credited to Chih-Wen CHENG, Ting-Hsu CHIEN, Jeng-Hung TSAI.
Application Number | 20190319455 16/453989 |
Document ID | / |
Family ID | 60418363 |
Filed Date | 2019-10-17 |
United States Patent
Application |
20190319455 |
Kind Code |
A1 |
CHIEN; Ting-Hsu ; et
al. |
October 17, 2019 |
DEVICE AND METHOD FOR GENERATING DUTY CYCLE
Abstract
A device for generating a duty cycle includes a converter, a
corrector, and a control circuit. The converter is configured to
generate a first output signal having a duty cycle to an output
terminal according to an input signal. The corrector is coupled to
the output terminal, and is configured to adjust the duty cycle of
the first output signal according to a control signal. The
converter is coupled in parallel with the corrector and between a
first power source and a second power source. The control circuit
is coupled to the output terminal, and is configured to generate
the control signal according to the first output signal and a
reference signal.
Inventors: |
CHIEN; Ting-Hsu; (HSINCHU
CITY, TW) ; CHENG; Chih-Wen; (HSINCHU CITY, TW)
; TSAI; Jeng-Hung; (HSINCHU CITY, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GLOBAL UNICHIP CORPORATION
TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD. |
HSINCHU CITY
HSINCHU |
|
TW
TW |
|
|
Family ID: |
60418363 |
Appl. No.: |
16/453989 |
Filed: |
June 26, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15255148 |
Sep 2, 2016 |
10389112 |
|
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16453989 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J 1/00 20130101; H02M
3/158 20130101; H03K 5/1565 20130101; H03L 7/0812 20130101 |
International
Class: |
H02J 1/00 20060101
H02J001/00; H03L 7/081 20060101 H03L007/081; H02M 3/158 20060101
H02M003/158; H03K 5/156 20060101 H03K005/156 |
Foreign Application Data
Date |
Code |
Application Number |
May 25, 2016 |
CN |
201610351867.0 |
Claims
1. A device for generating a duty cycle ratio for data, comprising:
a converter configured to generate a first output signal having the
duty cycle ratio to an output terminal according to an input
signal; a corrector coupled to the output terminal, and configured
to adjust the duty cycle ratio of the first output signal according
to a control signal, wherein the converter is coupled in parallel
with the corrector and between a first power source and a second
power source; and a control circuit coupled to the output terminal,
and configured to generate the control signal according to the
first output signal and a reference signal, wherein the corrector
comprises: a plurality of first current source circuits; a
plurality of first switches coupled between the first power source
and the first current source circuits, and configured to be turned
on according to a plurality of first switching signals, wherein
each of the first current source circuits is configured to generate
a first current to the output terminal on a condition that a
corresponding one of the first switches is turned on; a plurality
of second current source circuits; and a plurality of second
switches coupled between the second power source and the second
current source circuits, and configured to be turned on according
to a plurality of second switching signals, wherein each of the
second current source circuits is configured to generate a second
current on a condition that a corresponding one of the second
switches is turned on, and the second current flows from the output
terminal to the second power source.
2. The device of claim 1, wherein the control circuit comprises: a
comparator configured to generate the control signal according to
the first output signal and the reference signal; an encoder
configured to generate an encoded signal according to the control
signal; and a demultiplexer configured to generate the first
switching signals and the second switching signals according to the
encoded signal.
3. A device for generating a duty cycle ratio for data, comprising:
a first transistor; a second transistor configured to cooperate
with the first transistor to generate an output signal having the
duty cycle ratio to an output terminal according to an input
signal; and a corrector configured to generate at least one current
to the output terminal in response to the output signal, to adjust
the duty cycle ratio of the output signal, wherein the at least one
current is configured to be not flow through the first transistor
and the second transistor, wherein the corrector comprises: a
plurality of first current source circuits; a plurality of first
switches coupled between a first power source and the first current
source circuits, and configured to be turned on according to a
plurality of first switching signals, wherein each of the first
current source circuits is configured to generate a first current
of the at least one current to the output terminal on a condition
that a corresponding one of the first switches is turned on; a
plurality of second current source circuits; and a plurality of
second switches coupled between a second power source and the
second current source circuits, and configured to be turned on
according to a plurality of second switching signals, wherein each
of the second current source circuits is configured to generate a
second current on a condition that a corresponding one of the
second switches is turned on, and the second current flows from the
output terminal to the second power source.
4. The device of claim 3, further comprising: a control circuit
configured to control the corrector, wherein the control circuit
comprises: a comparator configured to generate a control signal
according to the first output signal and the reference signal; an
encoder configured to generate an encoded signal according to the
control signal; and a demultiplexer configured to generate the
first switching signals and the second switching signals according
to the encoded signal.
5. A method for generating a duty cycle ratio for data, comprising:
generating, by a converter, an output signal to an output terminal
according to an input signal; generating a control signal based on
the output signal and a reference signal; and generating, by a
corrector, at least one current according to the control signal,
and transmitting the at least one current to the output terminal
without transmitting through the converter to correct the duty
cycle ratio of the output signal, wherein the corrector comprises:
a plurality of first current source circuits; a plurality of first
switches coupled between the first power source and the first
current source circuits, and configured to be turned on according
to a plurality of first switching signals, wherein each of the
first current source circuits is configured to generate a first
current to the output terminal on a condition that a corresponding
one of the first switches is turned on; a plurality of second
current source circuits; and a plurality of second switches coupled
between the second power source and the second current source
circuits, and configured to be turned on according to a plurality
of second switching signals, wherein each of the second current
source circuits is configured to generate a second current on a
condition that a corresponding one of the second switches is turned
on, and the second current flows from the output terminal to the
second power source.
6. The method of claim 5, wherein generating the at least one
current comprises: generating, by a first current source circuit, a
first current of the at least one current to the output terminal on
a condition that a first switch is turned on, wherein the first
switch is configured to be turned on according to a first switching
signal; and generating, by a second current source circuit, a
second current of the at least one current to the output terminal
on a condition that a second switch is turned on, wherein the
second switch is configured to be turned on according to a second
switching signal, and the second current flows from the output
terminal to a power source.
7. The method of claim 6, further comprising: generating, by an
encoder, an encoded signal according to the control signal; and
generating, by a demultiplexer, the first switching signal and the
second switching signal according the encoded signal.
Description
RELATED APPLICATIONS
[0001] This is a divisional application of the U.S. application
Ser. No. 15/255,148, filed Sep. 2, 2016, which claims priority to
China Application Serial Number 201610351867.0, filed May 25, 2016,
all of which are herein incorporated by reference.
BACKGROUND
Technical Field
[0002] The present application relates to an integrated circuit.
More particularly, the present application relates to a device and
a method for generating a duty cycle.
Description of Related Art
[0003] In high-speed applications, which include, for example,
memory devices, data transmission and/or communication, etc, as a
tradeoff between a timing accuracy and a power consumption is
concerned, the design for a clock generation circuit has become
more and more difficult.
[0004] In some approaches, a clock scheme that employs a half-rate
can be operated without reducing the system operating speed. The
half-rate clock scheme usually requires a clock signal having a
duty cycle of 50%, so as to perform operations according to a
rising edge and a falling edge of this clock signal. However, in
practical applications, the duty cycle of the clock signal cannot
be kept accurately due to process variations and higher operating
speed, etc.
SUMMARY
[0005] Some aspects of the present disclosure provide a device for
generating a duty cycle. The device includes a converter, a
corrector, and a control circuit. The converter is configured to
generate a first output signal having a duty cycle to an output
terminal according to an input signal. The corrector is coupled to
the output terminal, and is configured to adjust the duty cycle of
the first output signal according to a control signal. The
converter is coupled in parallel with the corrector and between a
first power source and a second power source. The control circuit
is coupled to the output terminal, and is configured to generate
the control signal according to the first output signal and a
reference signal.
[0006] Some aspects of the present disclosure provide a device for
generating a duty cycle. The device includes a first transistor, a
second transistor, and a corrector. The second transistor is
configured to cooperate with the first transistor to generate an
output signal having a duty cycle to an output terminal according
to an input signal. The corrector is configured to generate at
least one current to the output terminal in response to the output
signal, to adjust the duty cycle of the output signal. The at least
one current is configured to be not flow through the first
transistor and the second transistor.
[0007] Some aspects of the present disclosure provide a method for
generating a duty cycle. The method includes the following
operations: generating, by a converter, an output signal to an
output terminal according to an input signal; generating a control
signal based on the output signal and a reference signal; and
generating at least one current according to the control signal,
and transmitting the at least one current to the output terminal
without transmitting through the converter to correct a duty cycle
of the output signal.
[0008] As described above, the devices and the method provided in
the present disclosure are able to correct the duty cycle of the
output signal, by an arrangement of generating parallel current
signals and a feedback mechanism, to improve the accuracy of the
duty cycle of the output signal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] This disclosure can be more fully understood by reading the
following detailed description of the embodiment, with reference
made to the accompanying drawings as follows:
[0010] FIG. 1 is a schematic diagram of a device for generating a
duty cycle, according to some embodiments of the present
disclosure.
[0011] FIG. 2 is a schematic diagram of transient waveforms of the
input signal and the output signal in FIG. 1, according to some
embodiments of the present disclosure.
[0012] FIG. 3 is a schematic diagram of a device for generating a
duty cycle, according to some other embodiments of the present
disclosure.
[0013] FIG. 4 is a flow chart of a method for generating a duty
cycle, according to some embodiments of the present disclosure.
DETAILED DESCRIPTION
[0014] Reference will now be made in detail to the present
embodiments of the disclosure, examples of which are illustrated in
the accompanying drawings. Wherever possible, the same reference
numbers are used in the drawings and the description to refer to
the same or like parts.
[0015] 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 used to distinguish one
element from another.
[0016] In this document, the term "coupled" may also be termed as
"electrically coupled," and the term "connected" may be termed as
"electrically connected." "Coupled" and "connected" may also be
used to indicate that two or more elements cooperate or interact
with each other.
[0017] Reference is now made to FIG. 1. FIG. 1 is a schematic
diagram of a device 100 for generating a duty cycle (hereinafter
referred to as the device 100), according to some embodiments of
the present disclosure. For illustration, the device 100 includes a
converter 110, a corrector 120, and a control circuit 130.
[0018] The converter 110 is configured to generate an output signal
VA to an output terminal 101 according to an input signal VIN, in
which the output signal VA has a duty cycle. In some embodiments,
the converter 110 is configured to convert a voltage signal to a
pulse signal. In some embodiments, the duty cycle of the output
signal VA is configured to be about 50%.
[0019] In some embodiments, the converter 110 includes a transistor
T1 and a transistor T2. A first terminal of the transistor T1 is
coupled to a power source 102 to receive a voltage VDD. A second
terminal of the transistor T1 is coupled to an output terminal 101,
and a control terminal of the transistor T1 is configured to
receive the input signal VIN. A first terminal of the transistor T2
is coupled to the output terminal 101, a second terminal of the
transistor T2 is coupled to a power source 103, and a control
terminal of the transistor T2 is configured to receive the input
signal VIN. In some embodiments, as shown in FIG. 1, the power
source 103 is a reference ground terminal. Alternatively, in some
other embodiments, the power source 103 is able to provide a system
voltage that is lower than the voltage VDD.
[0020] In some embodiments, the transistor T1 is configured to
cooperate with the transistor T2, according to the input signal
VIN, to generate the output signal VA. In some embodiments, the
transistor T1 and the transistor T2 are arranged as an inverter.
The arraignments of the converter 110 are given for illustrative
purposes only. Various types of the converter 110 are within the
contemplated scope of the present disclosure.
[0021] The corrector 120 is coupled to the output terminal 101, and
is configured to adjust the duty cycle of the output signal VA
based on the output signal VA. For illustration, the corrector 120
generates an current IU and an current ID to the output terminal
101 according to a control signal VC, to adjust the duty cycle of
the output signal VA, in which the control signal VC is generated,
by the control circuit 130, based on the output signal VA.
[0022] In some embodiments, the corrector 120 and the converter 110
are configured to be coupled in parallel with each other and
between the power sources 102 and 103. As a result, the corrector
120 is able to transmit the current IU and the current ID to the
output terminal 101 without flowing through the converter 110,
which includes, for example, the transistors T1 and T2.
[0023] For illustration, as shown in FIG. 1, the corrector 120
includes a current source circuit 121 and a current source circuit
122. The current source circuit 121 is coupled between the power
source 102 and the output terminal 101, and is configured to
generate the current IU to the output terminal 101 according to the
control signal VC. The current source circuit 122 is coupled
between the power source 103 and the output terminal 101, and is
configured to generate the current ID according to the control
signal VC, in which the current ID flows from the output terminal
101 to the power source 103.
[0024] In some embodiments, the current source circuits 121 and 122
are able to be implemented with voltage-controlled current source
circuits, in order to generate the current IU and the current ID
that have different values according to the control signal VC. In
some embodiments, variable current source circuits, which are
discussed above, are able to be implemented with various types of
current mirror circuits. The circuit implementations of the
corrector 120 are given for illustrative purposes only. Various
types of the corrector 120 are within the contemplated scope of the
present disclosure.
[0025] In some embodiments, the device 100 further includes a
buffer 140 and a buffer 150. The buffer 140 is coupled to the
output terminal 101 to generate an output signal VB, which has a
higher driving capability, to the control circuit 130 according to
the output signal VA. The buffer 150 is coupled to the output
terminal 101 to generate an output signal VOUT, which has a higher
driving capability, to an external electronic device (not shown)
according to the output signal VA. It is understood that the buffer
140 and the buffer 150 are able to be selectively applied. Person
skilled in the art would appreciate that the buffer 140 and the
buffer 150 are able to be selectively arranged according to
practical applications.
[0026] With continued reference to FIG. 1, the control circuit 130
is coupled to the output terminal 101 to generate the control
signal VC based on the output signal VA. For illustration, in some
embodiments, the control circuit 130 includes a comparator 131 and
an output capacitor CO that is coupled to an output node 104. The
comparator 131 is configured to compare the output signal VB with a
reference signal VREF, to generate the control signal VC to the
output node 104. In some other embodiments, the comparator 131 is
also able to be configured to directly receive the output signal VA
on a condition that the buffer 140 is not employed, and to compare
the output signal VA with the reference signal VREF to generate the
control signal VC.
[0027] FIG. 2 is a schematic diagram of transient waveforms of the
input signal VIN and the output signal VA in FIG. 1, according to
some embodiments of the present disclosure. For illustrating
related operations of the corrector 120, reference is now made to
both of FIGS. 1-2.
[0028] As shown in FIG. 2, an enabling period TDN (i.e., the time
interval of being at a high voltage level) of the input signal VIN
at each period is configured to be about the same as an disabling
period TUP (i.e., the time interval of being at a low voltage
level), of the input signal VIN at each period. During the enabling
period TDN of the input signal VIN, the transistor T1 is turned
off, and the transistor T2 is turned on. Under this condition, a
parasitic capacitance CP of the output terminal 101 is discharged
through the current IN of the transistor T2, and thus the voltage
level of the output signal VA is decreased. Alternatively, during
the disabling period TUP of the input signal VIN, the transistor T1
is turned on, and the transistor T2 is turned off. Under this
condition, the parasitic capacitance CP of the output terminal 101
is charged by the current IP of the transistor T1, and thus the
voltage level of the output signal VA is increased.
[0029] In an ideal condition, when the corrector 110 is not
operating, the voltage difference .DELTA.VA, which is generated
from the output signal VA during the charge-discharge progress, is
expected to be zero, in order to achieve a duty cycle of 50%. Such
relationship is able to be described as the following equation
(1):
.DELTA. VA = .intg. ( IP CP .times. TUP - IN CP .times. TDN ) = 0 (
1 ) ##EQU00001##
From the equation (1), in the ideal condition, if a product of the
current IP and the disabling period TUP could be the same as a
product of the current IN and the enabling period TDN, the voltage
difference .DELTA.VA is able to be zero. However, in practical
applications, the current IP and the current IN would have a
mismatch between each other due to process variations, internal
parasitic resistances of the transistors T1-T2, higher operating
speed, etc. Thus, the voltage difference .DELTA.VA is unable to be
zero. As a result, the duty cycle of the output signal cannot be
kept at 50% accurately.
[0030] In some embodiments, with the arrangement of the feedback
control of the control circuit 130, when a mismatch is present
between the current IP and the current IN, the different current IU
and the current ID are generated from the current source circuits
121 and 122 to the output terminal 101 for compensating, in order
to make the voltage difference .DELTA.VA be zero. Effectively, the
current mismatch is corrected. As a result, the duty cycle of the
input signal VA is able to be kept at 50%. Such operations are able
to be described as the following equation (2):
TUP.times.(IP+IU)=TDN.times.(IN+ID) (2)
[0031] In some approaches, the corrector, which is configured for
correcting the duty cycle, is connected to the converter in
cascode. In other words, the current, which is outputted from the
corrector, flows to the output terminal through the converter for
compensating. Accordingly, a mismatch is still present in the
current, which is outputted from the corrector, due to a parasitic
resistance of an internal transistor in the converter. As a result,
the duty cycle of the output signal cannot be kept at 50%
accurately. In addition, in the corrector that employs the cascode
circuit architecture, as the transmission path for transmitting the
current is much longer, and the control mechanism for such longer
transmission path is generally more complex, the duty cycle of the
output signal requires a longer stabling time. As a result, such
corrector in the approaches above is not able to be applied in a
higher speed application.
[0032] Compared with the approaches above, the corrector 120 in the
present disclosure is configured to be coupled in parallel with the
converter 110. In other words, the current IU and the current ID,
which are generated from the corrector 120, are transmitted to the
output terminal 101 without passing through the converter 110.
Compared with the approaches above, the duty cycle of the output
signal VA can be kept at 50% more accurately. Furthermore, as the
current IU and the current ID can be directly transmitted to the
output terminal 101, the duty cycle of the output signal VA can be
corrected back to 50% in a relatively faster speed. Relatively
speaking, the device 100 for generating the duty cycle is able to
be applied in a higher speed application.
[0033] Reference is now made to FIG. 3. FIG. 3 is a schematic
diagram of a device 300 for generating a duty cycle (hereinafter
the device 300), according to some other embodiments of the present
disclosure. With respect to FIG. 1, like elements in FIG. 3 are
designated with the same reference numbers for ease of
understanding.
[0034] Compared with the device 100 in FIG. 1, the corrector 120
and the control circuit 130 of the device 300 can be implemented
with digital circuits. For illustration, as shown in FIG. 3, the
corrector 120 includes current source circuits 321, current source
circuits 322, switches SW1, and switches SW2.
[0035] As shown in FIG. 3, each of the switches SW1 is coupled
between the power source 102 and a corresponding one of the current
source circuits 321. Each of the switches SW1 is configured to be
selectively turned on according to a corresponding one of switching
signals VS1. Each of the current source circuit 321 is configured
to generate the current IU to the output terminal 101 on a
condition that the corresponding switch SW1 is turned on.
[0036] Each of the switches SW2 is coupled between the power source
103 and a corresponding one of the current source circuit 322. Each
of the switches SW2 is configured to be selectively turned on
according to a corresponding one of switching signals VS2. Each of
the current source circuit 322 is configured to generate the
current ID, which flows from the output terminal 101 to the power
source 103, on a condition that the corresponding switch SW2 is
turned on.
[0037] With continued reference to FIG. 3, in some embodiments, the
control circuit 130 includes a comparator 131, an encoder 332, and
a demultiplexer 333. The comparator 131 is configured to compare
the output signal VB with the reference signal VREF, in order to
generate a control signal VC. The encoder 332 is coupled to an
output terminal of the comparator 131 to receive the control signal
VC. The encoder 332 is configured to generate an encoded signal VE
according to the control signal VC. For example, in some
embodiments, the encoder 332 encodes the control signal VC to
generate the encoded signal VE. Alternatively, in some other
embodiments, the encoder 332 is implemented with a counter, and is
configured to count according to the status of the control signal
VC, in order to generate a different encoded signal VE. The
demultiplexer 333 is coupled to an output terminal of the encoder
332 to receive the encoded signal VE. In some embodiments, the
encoded signal VE is configured to have n+1 bits, where n is a
positive integer, a number of the switches SW1 is n, and a number
of the switches SW2 is n. In some embodiments, the demultiplexer
333 is configured to, according to one bit of the encoded signal
VE, select outputs for remaining n bits of the encode signal VE, to
generate the switching signals VS1 and VS2.
[0038] With the arrangements above, when an offset is present in
the output signal VA, the comparator 131 outputs the control signal
VC having different statuses. The encoder 332 thus outputs the
different encoded signal VE. As a result, the demultiplexer 333
generates the corresponding switching signals VS1 and VS2 based on
the encoded signal VE, in order to turn on a corresponding number
of the switches SW1 and SW2 to generate the corresponding current
IU and the current ID to the output terminal 101. As described
above, effectively, the duty cycle of the output signal VA is
corrected to a predetermined duty cycle (e.g., 50%), by the current
IU and the current ID.
[0039] As described above, in some other embodiments, the
comparator 131 in FIG. 3 is also able to directly receive the
output signal VA on a condition that the buffer 140 is not
employed, and is able to compare the output signal VA with the
reference signal VREF to generate the control signal VC.
[0040] The arrangements of the corrector 120 and the control
circuit 130 are given for illustrative purposes only. Various types
of digital circuits, which are able to implement the corrector 120
and the control circuit 130, are also within the contemplated scope
of the present disclosure.
[0041] The values of the duty cycle in the various embodiments
above are given for illustrative purposes only. Various values of
the duty cycle are also within the contemplated scope of the
present disclosure.
[0042] Reference is now made to FIG. 4. FIG. 4 is a flow chart of a
method 400 for generating a duty cycle (hereinafter the method
400), according to some embodiments of the present disclosure. For
ease of understanding, reference is now made to both of FIG. 1 and
FIG. 4.
[0043] As shown in FIG. 4, the method 400 includes operations S410,
S420, and S430. In operation S410, the converter 110 generates the
output signal VA according to the input signal VIN. For
illustration, as shown in FIG. 1, the converter 110 is arranged as
an inverter circuit to generate a different output signal VA
according to the input signal VIN.
[0044] In operation S420, the control circuit 130 generates the
control signal VC based on the output signal VA and the reference
signal VREF. For illustration, as shown in FIG. 1, the comparator
131 can compare the output signal VB and the reference signal VREF
to generate the control signal VC, in which the output signal VB is
generated, according to the output signal VA, by the buffer
140.
[0045] In operation S430, the corrector 120 generates the current
IU and the current ID according to the control signal VC, and
transmits the current IU and the current ID to the output terminal
101 without transmitting through the converter 110, in order to
correct the duty cycle of the output signal VA. For illustration,
as shown in FIG. 1, the current source circuits 121 and 122
selectively provide the current IU and the current ID, according to
the control signal VC, to the output terminal 101. Both of the
current source circuits 121 and 122 are coupled in parallel with
the converter 110 and between the current sources 102 and 103. As a
result, the current IU and the current ID can be transmitted to the
output terminal 101 without passing through the converter 110.
[0046] As described above, the device 100 and the method 400
provided in the present disclosure are able to correct the duty
cycle of the output signal, by an arrangement of generating
parallel current signals and a feedback mechanism, to improve the
accuracy of the duty cycle of the output signal.
[0047] Although the present disclosure has been described in
considerable detail with reference to certain embodiments thereof,
other embodiments are possible. Therefore, the spirit and scope of
the appended claims should not be limited to the description of the
embodiments contained herein. It will be apparent to those skilled
in the art that various modifications and variations can be made to
the structure of the present disclosure without departing from the
scope or spirit of the disclosure. In view of the foregoing, it is
intended that the present disclosure cover modifications and
variations of this disclosure provided they fall within the scope
of the following claims.
* * * * *