WO2022230030A1 - Capacitive sensor system and current conveyor for capacitive sensor system - Google Patents
Capacitive sensor system and current conveyor for capacitive sensor system Download PDFInfo
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- WO2022230030A1 WO2022230030A1 PCT/JP2021/016687 JP2021016687W WO2022230030A1 WO 2022230030 A1 WO2022230030 A1 WO 2022230030A1 JP 2021016687 W JP2021016687 W JP 2021016687W WO 2022230030 A1 WO2022230030 A1 WO 2022230030A1
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- 239000003990 capacitor Substances 0.000 claims abstract description 29
- 230000001105 regulatory effect Effects 0.000 claims description 3
- 230000015654 memory Effects 0.000 description 12
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- 238000004590 computer program Methods 0.000 description 6
- 230000006870 function Effects 0.000 description 6
- 230000003071 parasitic effect Effects 0.000 description 5
- 230000004044 response Effects 0.000 description 5
- 238000001514 detection method Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000005669 field effect Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
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- 230000003068 static effect Effects 0.000 description 1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/0416—Control or interface arrangements specially adapted for digitisers
- G06F3/0418—Control or interface arrangements specially adapted for digitisers for error correction or compensation, e.g. based on parallax, calibration or alignment
- G06F3/04182—Filtering of noise external to the device and not generated by digitiser components
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
Definitions
- the present disclosure relates to capacitive sensors, and more particularly to a current conveyor for a capacitive sensor.
- An electronic device may implement a capacitive sensor configured to sense contact between an object (e.g., a finger) and a surface, such as a surface of the electronic device, and generate a sensed signal indicative of the sensed contact.
- a reference signal generator e.g., a waveform generator
- the control signal is sinusoidal (i.e., the control signal is a sine wave).
- the sensed signal corresponds to changes in an amplitude and/or phase of the control signal based on whether an object is contacting the sensor. Accordingly, the presence or absence of an object contacting the sensor can be determined based on the amplitude or phase of the sensed signal (for example, see PTL 1).
- a current conveyer circuit including an operational amplifier and field-effect transistors (FETs) constituting a current mirror circuit detects an object (e.g., a finger) by measuring changes in charge that occur due to changes in capacitances caused by the object coming into contact with the capacitive sensor.
- FETs field-effect transistors
- a capacitive sensor system includes a capacitive sensor and a current conveyor coupled to an output of the capacitive sensor.
- the current conveyor includes an input side including first and second transistors coupled to an input voltage, an output side including third and fourth transistors coupled to the capacitive sensor, a first capacitor coupled between a gate and a source of the third transistor, and a second capacitor coupled between a gate and a source of the fourth transistor.
- the current conveyor is a second generation current conveyor.
- the current conveyor includes a first node coupled to a control signal, a second node coupled to the output of the capacitive sensor, and a third node outputting an output current based on the control signal and the output of the capacitive sensor.
- the output of the capacitive sensor is a sensed signal corresponding to the control signal as modified in accordance with at least one of contact with and proximity of an object.
- the control signal coupled to the first node is the input voltage of the current conveyor and the second node outputs a regulated voltage corresponding to the input voltage.
- the current conveyor includes a current mirror circuit coupled to the output side, and wherein the third node is coupled to the current mirror circuit.
- the output side includes fifth, sixth, seventh, and eighth transistors, the current mirror circuit includes the seventh transistor and the eighth transistor, and the third node is coupled between the seventh transistor and the eighth transistor. Gates of the first transistor and the seventh transistor are coupled together.
- a fourth node between the first capacitor and the second capacitor is coupled to the second node. Gates of the first transistor and the third transistor are coupled together and gates of the second transistor and the fourth transistor are coupled together.
- a reference signal generator is configured to provide a control signal to the input side of the current conveyor.
- An offset control module coupled to the output side of the current conveyor.
- a current conveyor for a capacitive sensor system includes an input side coupled to an input voltage and including first and second transistors, an output side that provides an output voltage coupled to a capacitive sensor and an output current and including third and fourth transistors, a first capacitor coupled between a gate and a source of the third transistor, and a second capacitor coupled between a gate and a source of the fourth transistor.
- the current conveyor is a second generation current conveyor.
- the first capacitor and the second capacitor are configured to function as a low pass filter.
- the current conveyor includes a first node coupled to the input voltage, a second node that outputs the output voltage, and a third node that outputs the output current.
- the third node is coupled to the current mirror circuit.
- a capacitive sensor system that can alleviate voltage changes across the gate and source terminals in response to transient voltage changes at the source terminals of the FETs in the current conveyer circuit, and maintain the current flowing through the FETs at the output side that would be otherwise changed by the gate-source voltage changes.
- FIG. 1 is an example electronic device including a capacitive sensor
- FIG. 2A is an example reference signal generator for a capacitive sensor
- FIG. 2B is an example reference signal generator for a capacitive sensor
- FIG. 3 is an example capacitive sensor system implementing current conveyor for a capacitive sensor according to the present disclosure
- FIG. 4 is an example current conveyor according to the present disclosure.
- a change in a signal supplied to a capacitive sensor (corresponding to a sensed signal) in response to a contact with an object is typically small relative to a supplied signal (i.e., a control or drive signal) and may be difficult to detect. Accordingly, different methods may be implemented to improve detection of the change.
- a reference signal generator that provides the signal to the sensor may also supply a duplicate of the signal or a second reference signal generator can be provided to supply the duplicate of the signal. The duplicated signal is subtracted from the supplied signal and the result, which can be amplified to improve detection, corresponds to the sensed signal.
- the reference signal generator is a sinewave generator such as a Wien bridge oscillator.
- the reference signal generator may be configured to supply a digital sine wave to a digital-to-analog converter (DAC) and the output of the DAC is filtered and/or amplified.
- DAC digital-to-analog converter
- an offset control module is configured to generate an offset signal that is a duplicate of the sensed signal when there is no contact between an object and the capacitive sensor.
- An electronic device including the capacitive sensor may include a regulator circuit (e.g., a voltage-controlled current mode regulator) coupled to an output of the capacitive sensor.
- the regulator circuit is configured to regulate an output voltage of the capacitive sensor (corresponding to the sensed signal) and generate an output current indicative of the sensed signal.
- the regulator circuit is implemented as a current conveyor.
- a current conveyor according to the principles of the present disclosure includes a low-pass filter (LPF) coupled between an input voltage and the output current of the current conveyor. The LPF improves noise rejection of the current conveyor.
- LPF low-pass filter
- a reference signal generator e.g., a waveform generator
- a reference or control signal e.g., a square wave, a sinewave, etc.
- the reference signal generator 108 may supply the control signal 110 to an offset control module 112 or an optional second reference signal generator 116 may provide a duplicate of the control signal 110 to the offset control module 112.
- the sensor module 104 modifies the control signal 110 and generates a sensed signal 118 based on the control signal 110 and proximity or contact with a sensed object.
- the sensed signal 118 corresponds to the control signal 110 as modified in accordance with detection of (e.g., contact with and/or proximity of) an object.
- the sensed signal 118 is indicative of whether an object (e.g., a finger) is in contact with the sensor module 104.
- the sensed signal 118 indicates a proximity of the object to the sensor module 104.
- the sensed signal 118 may differ (e.g., in amplitude and/or phase) from the control signal 110 regardless of whether an object is in contact with the sensor module 104.
- the offset control module 112 is configured to generate an offset signal 120 that is a duplicate of the sensed signal 118 without contact between an object and the sensor module 104.
- the offset control module 112 is configured to modify the control signal 110 in the same manner as the sensor module 104 when there is no contact between an object and the sensor module 104 (and/or, in some examples, when the object is not sufficiently near the sensor module 104 to affect the sensed signal 118).
- the sensed signal 118 and the offset signal 120 will be essentially the same (e.g., in magnitude, phase, and/or both magnitude and phase) and a difference between the sensed signal 118 and the offset signal 120 will approach zero.
- the offset signal 120 may be configured to have an opposite polarity relative to the control signal 110 and may simply be summed with the sensed signal 118.
- a regulator circuit 124 outputs and amplifies a difference between the offset signal 120 and the sensed signal 118.
- An output signal 128 (e.g., an output current) of the regulator circuit 124 indicative of the sensed signal 118 may then be processed to detect contact between the sensor module 104 and an object. For example, contact may be determined based on whether an amplitude and/or a phase of the output signal 128 exceeds a respective threshold.
- the sensed signal 118 may be indicative of a proximity of the object to the sensor module 104 regardless of whether the object is in direct contact with the sensor module 104. In these examples, the sensed signal 118 may be further indicative of a distance between the object and the sensor module 104.
- the regulator circuit 124 is further configured to regulate a voltage provided to the sensor module 104 (e.g., a voltage of the control signal 110).
- the regulator circuit 124 may be a voltage-controlled current mode regulator implemented as a current conveyor.
- the current conveyor according to the principles of the present disclosure includes an LPF coupled between an input voltage (e.g., the voltage of the control signal 110) and the output current of the current conveyor to improve noise rejection as described below in more detail.
- the reference signal generator 108 implements a Wien bridge oscillator, which may be difficult to tune and/or to modulate amplitude.
- the reference signal generator 108 may generate a digital sinewave that is subsequently converted to an analog sinewave.
- the reference signal generator 108 may include a digital sinewave generator 200.
- an analog DAC 204 converts the digital sinewave to an analog signal, which is then filtered and amplified (or, in some examples, attenuated) using an LPF 208 having gain control capabilities.
- an amplitude control signal is provided to the LPF 208 to control the gain.
- the LPF 208 may be a first order filter to reduce cost or, in some examples, may be a second, third, or higher order filter. In other examples, a band pass filter may be used.
- a multiplier 212 is provided between the digital sinewave generator 200 and the analog DAC 204.
- the amplitude control signal is provided to the multiplier 212 to control the gain.
- the output of the multiplier (corresponding to the amplified digital sinewave) is provided to the analog DAC 204.
- the analog signal output by the analog DAC 204 is filtered using an LPF 216 without gain control.
- an example capacitive sensor system 300 (e.g., a capacitive sensor system 300 for the electronic device 100) including a sensor module 304 (e.g., a capacitive sensor) and implementing a regulator circuit 308 according to the present disclosure is shown.
- a reference signal generator 312 outputs a reference or control signal 316 (e.g., a modulated waveform such as a square wave, an analog sinewave, a digital waveform such as a digital sinewave that is converted to an analog sinewave, etc.).
- the control signal 316 is supplied to the sensor module 304 via the regulator circuit 308 and, in some examples, to an offset control module 320.
- the offset control module 320 is configured to generate an offset signal 324 based on the control signal 316.
- the offset signal 324 is provided to the regulator circuit 308.
- the sensor module 304 corresponds to a capacitive sensor (e.g., a capacitive touch circuit) including one or more parasitic capacitances (e.g., parasitic capacitance Crg) that modify an amplitude and phase of the control signal 316 provided to the regulator circuit 308.
- the control signal 316 is connected to the one or more sensing electrodes through a capacitance Crs.
- a capacitance 336 of the finger 332 further modifies the amplitude and phase of a sensed signal 340 that is based on the control signal 316.
- the sensor module 304 generates, as an output voltage, the sensed signal 340 indicative of whether an object such as the finger 332 is in contact with the sensor module 304 or, in some examples, a proximity of the finger 332 to the sensor module 304. More specifically, the sensed signal 340 is modified in accordance with the detected capacitance 336.
- the regulator circuit 308 detects and outputs an indication of the sensed signal 340. In some examples, the regulator circuit 308 detects and outputs a difference between the sensed signal 340 and the offset signal 324.
- the offset control module 320 is configured such that the sensed signal 340 and the offset signal 324 (i.e., respective amplitudes and phases of the sensed signal 340 and the offset signal 324) are the same when there is no contact between the sensor module 304 (e.g., the one or more sensing electrodes) and an object such as the finger 332.
- the offset control module 320 is configured to adjust a phase and an amplitude of the offset signal 324 such that the output of the regulator circuit 308 (e.g., an output signal 344, corresponding to an output current) becomes substantially zero when there is no contact between the sensor module 304 (the one or more sensing electrodes) and the object.
- the output of the regulator circuit 308 e.g., an output signal 344, corresponding to an output current
- the offset control module 320 is configured to adjust the phase and the amplitude of the offset signal 324 such that the phase and the amplitude of the offset signal 324 respectively coincide with a phase and an amplitude of the sensed signal 340 when the sensing electrodes of the sensor module 304 do not sense the proximity of or contact with an object.
- the parasitic capacitances Crs and Crg modify the amplitude and phase of the control signal 316.
- the offset control module 320 adjusts the amplitude and the phase of the offset signal 324 to compensate for the changes to the control signal 316 caused by the parasitic capacitances Crs and Crg.
- the output of the regulator circuit 308 indicates whether there is contact between the sensor module 304 and the finger 332 or, in some examples, a proximity of the finger 332 to the sensor module 304 based on a comparison between the sensed signal 340 and the offset signal 324.
- the regulator circuit 308 receives the control signal 316 (e.g., as an input voltage of the regulator circuit 308) from the reference signal generator 312.
- the regulator circuit 308 is configured to regulate a voltage coupled to the sensor module 304 (e.g., a voltage of the control signal 316).
- the voltage coupled to the sensor module 304 corresponds to a voltage coupled to an optional sensor input/output (I/O) pad 348 that is further coupled to an output of the sensor module 304.
- the sensed signal 340 corresponds to an output voltage of the regulator circuit 308 that is generated based on the control signal 316 and is further modified by the detected capacitance 336.
- the regulator circuit 308 generates the output signal 344 (e.g., the output current) indicative of the sensed signal 340.
- the regulator circuit 308 includes a current conveyor 400, such as a second generation current conveyor (CCII).
- the current conveyor 400 includes an input side 404 and an output side 408 each coupled between a supply voltage (e.g., VDD) and a reference potential (e.g., a ground terminal).
- the input side 404 includes first and second transistors 412 and 416 (e.g., field effect transistors (FETs) and current sources (e.g., adjustable current sources) 420 and 424.
- FETs field effect transistors
- current sources 420 and 424 may be implemented with transistors. Respective gates and sources of the first and second transistors 412 and 416 are coupled together.
- the current source 420 is coupled between the supply voltage and the first transistor 412.
- the current source 424 is coupled between the second transistor 416 and ground.
- the output side 408 includes third, fourth, fifth, and sixth transistors (e.g., FETs) 428, 432, 436, and 440.
- a gate of the third transistor 428 is coupled to a gate of the first transistor 412.
- a gate of the fourth transistor 432 is coupled to a gate of the second transistor 416.
- Third transistor 428 and the fourth transistor 432 are coupled to the sensor module 304.
- the fifth transistor 436 is coupled between the supply voltage and the third transistor 428.
- the sixth transistor 440 is coupled between the fourth transistor 432 and ground.
- a first node 444 between the first transistor 412 and the second transistor 416 functions as an input voltage node (e.g., a Y node) of the current conveyor 400.
- the first node 444 receives an input voltage, such as an input voltage corresponding to the control signal 316 from the reference signal generator 312.
- the first and second transistors 412 and 416 are coupled to the input voltage via the node 444 and maintain a bias voltage reference based on the input voltage received at the first node 444.
- a second node 448 between the third transistor 428 and the fourth transistor 432 functions as an output voltage node (e.g., an X node) of the current conveyor 400.
- gate voltages of the first and second transistors 412 and 416 control gate voltages of the third and fourth transistors 428 and 432 such that the voltage at the second node 448 is equal to the input voltage received at the first node 444.
- the second node 448 outputs a regulated output voltage corresponding to the input voltage received at the first node 444.
- An output of the sensor module 304 is coupled to the output voltage of the second node 448. Accordingly, the voltage provided to the sensor module 304 corresponds to the output voltage of the second node 448, which in turn corresponds to the input voltage provided to the first node 444.
- the third and fourth transistors 428 and 432 together supply a current required to maintain the output voltage at the second node 448. In other words, as the detected capacitance 336 changes, an amount of current required to maintain the output voltage of the second node 448 at the same input voltage as the first node 444 also changes. In this manner, a summed current of the third and fourth transistors 428 and 432 is an output current corresponding to the sensed signal 340.
- the current conveyor 400 further includes seventh and eighth transistors 452 and 456. Gates of the seventh and eighth transistors 452 and 456 are coupled to respective gates of the fifth and sixth transistors 436 and 440.
- the seventh transistor 452 and the eighth transistor 456 form a current mirror circuit.
- the fifth and sixth transistors 436 and 440 provide a gate voltage that is indicative of a current-to-voltage relationship to be replicated by the current mirror circuit formed by the seventh and eighth transistors 452 and 456.
- a third node 460 is coupled to the current mirror circuit between the seventh transistor 452 and the eighth transistor 456 and functions as an output current node (e.g., a Z node) of the current conveyor 400.
- the third node 460 outputs the output signal 344 of the regulator circuit 308, which corresponds to the output current that indicates whether there is contact between the sensor module 304 and the finger 332 or, in some examples, a proximity of the finger 332 to the sensor module 304.
- the third node 460 is coupled to an offset current (e.g., the offset signal 324) and the output signal 344 corresponds to a sum of the output current and the offset current.
- the offset current is configured to have an opposite polarity relative to a current of the control signal 316.
- the output signal 344 is provided to an output signal path (e.g., an output signal path of the capacitive sensor system 300).
- the current conveyor 400 includes a dedicated low pass filter 464 coupled between the input voltage (i.e., the first node 446) and the output current (i.e., the third node 460) to improve the noise rejection performance of the current conveyor 400.
- the low pass filter 464 lowers a low pass cutoff frequency of the current conveyor 400 and filters high frequency voltages in the input voltage from the output current.
- the low pass filter 464 prevents high frequency voltages in the input voltage from being translated into high frequency currents in the output current at the third node 460.
- the low pass filter 464 includes first and second capacitors 468 and 472 coupled between gates of the third and fourth transistors 428 and 432. Capacitance values of the first and second capacitors 468 and 472 may be selected in accordance with a desired low pass cutoff frequency of the current conveyor 400. For example, as respective capacitances of the first and second capacitors 468 and 472 increase, the low pass cutoff frequency of the current conveyor 400 decreases.
- a fourth node 476 between the first and second capacitors 468 and 472 is coupled to the second node 448 between the third and fourth transistors 428 and 432.
- the first capacitor 468 is connected between a gate and source of the third transistor 428 and the second capacitor 472 is connected between a gate and source of the fourth transistor 432.
- the low pass filter 464 includes first and second resistors R1 and R2.
- the first resistor R1 is coupled between the first capacitor 468 and the gate and the source of the first transistor 412.
- the second resistor R2 is coupled between the second capacitor 472 and the gate and the source of the second transistor 416.
- the first and second resistors R1 and R2 further adjust the low pass cutoff frequency of the current conveyor 400. For example, increasing the resistances of the first and second resistors R1 and R2 decreases the low pass cutoff frequency of the current conveyor 400.
- Spatial and functional relationships between elements are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements.
- the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean "at least one of A, at least one of B, and at least one of C.”
- the direction of an arrow generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration.
- information such as data or instructions
- the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A.
- element B may send requests for, or receipt acknowledgements of, the information to element A.
- module or the term “controller” may be replaced with the term “circuit.”
- the term “module” may refer to, be part of, or include: an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.
- ASIC Application Specific Integrated Circuit
- FPGA field programmable gate array
- the module may include one or more interface circuits.
- the interface circuits may include wired or wireless interfaces that are connected to a local area network (LAN), the Internet, a wide area network (WAN), or combinations thereof.
- LAN local area network
- WAN wide area network
- the functionality of any given module of the present disclosure may be distributed among multiple modules that are connected via interface circuits. For example, multiple modules may allow load balancing.
- a server (also known as remote, or cloud) module may accomplish some functionality on behalf of a client module.
- code may include software, firmware, and/or microcode, and may refer to programs, routines, functions, classes, data structures, and/or objects.
- shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules.
- group processor circuit encompasses a processor circuit that, in combination with additional processor circuits, executes some or all code from one or more modules. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above.
- shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules.
- group memory circuit encompasses a memory circuit that, in combination with additional memories, stores some or all code from one or more modules.
- the term memory circuit is a subset of the term computer-readable medium.
- the term computer-readable medium does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave); the term computer-readable medium may therefore be considered tangible and non-transitory.
- Non-limiting examples of a non-transitory, tangible computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).
- nonvolatile memory circuits such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit
- volatile memory circuits such as a static random access memory circuit or a dynamic random access memory circuit
- magnetic storage media such as an analog or digital magnetic tape or a hard disk drive
- optical storage media such as a CD, a DVD, or a Blu-ray Disc
- the apparatuses and methods described in this application may be partially or fully implemented by a special purpose computer created by configuring a general purpose computer to execute one or more particular functions embodied in computer programs.
- the functional blocks, flowchart components, and other elements described above serve as software specifications, which can be translated into the computer programs by the routine work of a skilled technician or programmer.
- the computer programs include processor-executable instructions that are stored on at least one non-transitory, tangible computer-readable medium.
- the computer programs may also include or rely on stored data.
- the computer programs may encompass a basic input/output system (BIOS) that interacts with hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.
- BIOS basic input/output system
- the computer programs may include: (i) descriptive text to be parsed, such as HTML (hypertext markup language), XML (extensible markup language), or JSON (JavaScript Object Notation) (ii) assembly code, (iii) object code generated from source code by a compiler, (iv) source code for execution by an interpreter, (v) source code for compilation and execution by a just-in-time compiler, etc.
- source code may be written using syntax from languages including C, C++, C#, Objective C, Swift, Haskell, Go, SQL, R, Lisp, Java (registered trademark), Fortran, Perl, Pascal, Curl, OCaml, Javascript (registered trademark), HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash (registered trademark), Visual Basic (registered trademark), Lua, MATLAB, SIMULINK, and Python (registered trademark).
- languages including C, C++, C#, Objective C, Swift, Haskell, Go, SQL, R, Lisp, Java (registered trademark), Fortran, Perl, Pascal, Curl, OCaml, Javascript (registered trademark), HTML5 (Hypertext Markup Language 5th revision), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Ei
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Abstract
Description
[PTL 1] United States Patent No. 9,727,183
100 ELECTRONIC DEVICE
104 SENSOR MODULE
108 REFERENCE SIGNAL GENERATOR
110 CONTROL SIGNAL
112 OFFSET CONTROL MODULE
116 OPTIONAL SECOND REFERENCE SIGNAL GENERATOR |
118 SENSED SIGNAL
120 OFFSET SIGNAL
124 REGULATOR CIRCUIT
128 OUTPUT SIGNAL
200 DIGITAL SINEWAVE GENERATOR
208 LPF
212 MULTIPLIER
216 LPF
300 CAPACITIVE SENSOR SYSTEM
304 SENSOR MODULE
308 REGULATOR CIRCUIT
312 REFERENCE SIGNAL GENERATOR
316 CONTROL SIGNAL
320 OFFSET CONTROL MODULE
324 OFFSET SIGNAL
332 FINGER
336 CAPACITANCE
340 SENSED SIGNAL
344 OUTPUT SIGNAL
400 CURRENT CONVEYOR
404 INPUT SIDE
408 OUTPUT SIDE
412 FIRST TRANSISTOR
416 SECOND TRANSISTOR
420 CURRENT SOURCE
424 CURRENT SOURCE
428, 432, 436, 440 THIRD, FOURTH, FIFTH, AND SIXTH TRANSISTORS
444 FIRST NODE
448 SECOND NODE
452 SEVENTH TRANSISTOR
456 EIGHTH TRANSISTOR
460 THIRD NODE
464 LOW PASS FILTER
468 FIRST CAPACITOR
472 SECOND CAPACITOR
476 FOURTH NODE
Crs, Crg PARASITIC CAPACITANCES
R1 FIRST RESISTOR
R2 SECOND RESISTOR
Claims (15)
- A capacitive sensor system, comprising:
a capacitive sensor; and
a current conveyor coupled to an output of the capacitive sensor, wherein the current conveyor includes
an input side including first and second transistors coupled to an input voltage,
an output side including third and fourth transistors coupled to the capacitive sensor,
a first capacitor coupled between a gate and a source of the third transistor, and
a second capacitor coupled between a gate and a source of the fourth transistor.
- The capacitive sensor system of claim 1, wherein the current conveyor is a second generation current conveyor.
- The capacitive sensor system of claim 1, wherein the current conveyor includes a first node coupled to a control signal, a second node coupled to the output of the capacitive sensor, and a third node outputting an output current based on the control signal and the output of the capacitive sensor.
- The capacitive sensor system of claim 3, wherein the output of the capacitive sensor is a sensed signal corresponding to the control signal as modified in accordance with at least one of contact with and proximity of an object.
- The capacitive sensor system of claim 4, wherein the control signal coupled to the first node is the input voltage of the current conveyor and the second node outputs a regulated voltage corresponding to the input voltage.
- The capacitive sensor system of claim 5, wherein the current conveyor includes a current mirror circuit coupled to the output side, and wherein the third node is coupled to the current mirror circuit.
- The capacitive sensor system of claim 6, wherein the output side includes fifth, sixth, seventh, and eighth transistors, the current mirror circuit includes the seventh transistor and the eighth transistor, and the third node is coupled between the seventh transistor and the eighth transistor.
- The capacitive sensor system of claim 7, wherein gates of the first transistor and the seventh transistor are coupled together.
- The capacitive sensor system of claim 3, wherein a fourth node between the first capacitor and the second capacitor is coupled to the second node.
- The capacitive sensor system of claim 1, wherein gates of the first transistor and the third transistor are coupled together and gates of the second transistor and the fourth transistor are coupled together.
- The capacitive sensor system of claim 1, further comprising a reference signal generator configured to provide a control signal to the input side of the current conveyor.
- The capacitive sensor system of claim 11, further comprising an offset control module coupled to the output side of the current conveyor.
- A current conveyor for a capacitive sensor system, the current conveyor comprising:
an input side including first and second transistors coupled to an input voltage;
an output side including third and fourth transistors, wherein the output side provides an output voltage and an output current, and wherein the output voltage is coupled to a capacitive sensor;
a first capacitor coupled between a gate and a source of the third transistor; and
a second capacitor coupled between a gate and a source of the fourth transistor.
- The current conveyor of claim 13, wherein the first capacitor and the second capacitor are configured to function as a low pass filter.
- The current conveyor of claim 14, wherein the current conveyor includes a first node coupled to the input voltage, a second node that outputs the output voltage, and a third node that outputs the output current.
Priority Applications (5)
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CN202180096118.7A CN117043726A (en) | 2021-04-26 | 2021-04-26 | Capacitive sensor system and current transmitter for a capacitive sensor system |
KR1020237037663A KR20230161519A (en) | 2021-04-26 | 2021-04-26 | Capacitive sensor systems and current conveyors for capacitive sensor systems |
DE112021007594.2T DE112021007594T5 (en) | 2021-04-26 | 2021-04-26 | CAPACITIVE SENSOR SYSTEM AND CURRENT CONVEYOR FOR CAPACITIVE SENSOR SYSTEM |
JP2023564383A JP2024518295A (en) | 2021-04-26 | 2021-04-26 | Capacitive sensor system and current conveyor for a capacitive sensor system - Patents.com |
PCT/JP2021/016687 WO2022230030A1 (en) | 2021-04-26 | 2021-04-26 | Capacitive sensor system and current conveyor for capacitive sensor system |
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PCT/JP2021/016687 WO2022230030A1 (en) | 2021-04-26 | 2021-04-26 | Capacitive sensor system and current conveyor for capacitive sensor system |
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KR (1) | KR20230161519A (en) |
CN (1) | CN117043726A (en) |
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WO (1) | WO2022230030A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US6316998B1 (en) * | 1997-11-12 | 2001-11-13 | Nec Corporation | Differential amplifier and a method of compensation |
JP2009110418A (en) * | 2007-10-31 | 2009-05-21 | Epson Imaging Devices Corp | Display device and electronic equipment |
JP2010191834A (en) * | 2009-02-20 | 2010-09-02 | Renesas Electronics Corp | Data processing system and microcomputer |
US20130314109A1 (en) * | 2009-03-26 | 2013-11-28 | Viktor Kremin | Multi-functional capacitance sensing circuit with a current conveyor |
US20160370948A1 (en) * | 2015-06-22 | 2016-12-22 | Samsung Electronics Co., Ltd. | Touch screen controller, touch sensing device, and touch sensing method |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
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KR20150042366A (en) | 2013-10-10 | 2015-04-21 | 삼성전자주식회사 | Touch screen sensror integrated circuit, method thereof, and system having the same |
-
2021
- 2021-04-26 WO PCT/JP2021/016687 patent/WO2022230030A1/en active Application Filing
- 2021-04-26 CN CN202180096118.7A patent/CN117043726A/en active Pending
- 2021-04-26 KR KR1020237037663A patent/KR20230161519A/en unknown
- 2021-04-26 DE DE112021007594.2T patent/DE112021007594T5/en active Pending
- 2021-04-26 JP JP2023564383A patent/JP2024518295A/en active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6316998B1 (en) * | 1997-11-12 | 2001-11-13 | Nec Corporation | Differential amplifier and a method of compensation |
JP2009110418A (en) * | 2007-10-31 | 2009-05-21 | Epson Imaging Devices Corp | Display device and electronic equipment |
JP2010191834A (en) * | 2009-02-20 | 2010-09-02 | Renesas Electronics Corp | Data processing system and microcomputer |
US20130314109A1 (en) * | 2009-03-26 | 2013-11-28 | Viktor Kremin | Multi-functional capacitance sensing circuit with a current conveyor |
US20160370948A1 (en) * | 2015-06-22 | 2016-12-22 | Samsung Electronics Co., Ltd. | Touch screen controller, touch sensing device, and touch sensing method |
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KR20230161519A (en) | 2023-11-27 |
JP2024518295A (en) | 2024-05-01 |
DE112021007594T5 (en) | 2024-02-15 |
CN117043726A (en) | 2023-11-10 |
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