Extended acquisition and measurement of capacitive sensors and related systems, methods and devices

Abstract

Embodiments of the present disclosure generally relate to techniques for parallel acquisition and measurement and related circuits, systems, and devices that implement those techniques. Techniques for parallel acquisition and measurement generally include simultaneously acquiring sense signals from multiple sensor channels and determining which of the acquired sense signals has the greatest relative contribution to the measurement.

Description

[0001] Priority declaration

[0002] This application claims the benefit of the filing date of U.S. Provisional Patent Application Serial No. 62 / 688,254, filed on June 21, 2018, entitled “Spread Measurement of Capacitance Sensors and Related Systems, Methods and Devices,” and claims the benefit of the filing date of pending U.S. Patent Application Serial No. 16 / 109,420, filed on August 22, 2018, entitled “Spread Acquisition and Measurement of Capacitance Sensors and Related Systems, Methods and Devices,” which application also claims priority to U.S. Provisional Patent Application Serial No. 62 / 688,254, the contents and disclosures of each of which are hereby incorporated by reference in their entirety. Technical Field

[0003] Embodiments of the present disclosure relate generally to capacitive sensing, and more particularly, to extended acquisition and measurement techniques for sensing channels of capacitive sensors, and related systems, methods, and devices. Background Art

[0004] A typical touch interface system may incorporate a touch sensor (capacitive, resistive, etc.) that responds to an object that is in close proximity to or physically in contact with a touch-sensitive surface of the touch interface system. The response may be captured and interpreted to infer information about the contact, including the location on the interface. Touchpads used with personal computers (including laptops and keyboards for tablets) typically incorporate touch interface systems or operate in conjunction with touch interface systems. Displays typically include a touch screen that incorporates elements of a touch interface system (typically at least a touch sensor) to enable a user to interact with a graphical user interface (GUI) and / or computer applications. Examples of devices incorporating touch displays include portable media players, televisions, smart phones, tablet computers, personal computers, and wearable devices such as smart watches, to name a few. In addition, control panels for automobiles, household appliances (e.g., ovens, refrigerators, washing machines, etc.), security systems, automated teller machines (ATMs), residential environmental control systems, and industrial equipment may incorporate touch interface systems, including enabling buttons, sliders, and other touch elements.

[0005] The inventors of the present disclosure understand that, by way of example, displays, household appliances, and moisture can introduce noise into a touch interface system, and that noise coupling can cause unwanted mutual capacitance effects at the sensors and acquisition circuits.Conventional touch interface systems can have other drawbacks and deficiencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The objects and advantages of various embodiments of the present disclosure will be apparent to those skilled in the art through detailed description in conjunction with the accompanying drawings:

[0007] Figure 1 A representative diagram illustrating the operation of a touch system in accordance with an embodiment of the present disclosure that incorporates acquisition and measurement techniques using simultaneous acquisition codes and extended codes;

[0008] Figure 2 A capacitive sensing system incorporating encoding techniques in acquisition and measurement according to an embodiment of the present disclosure is shown;

[0009] Figure 3 A representative diagram illustrating the operation of a capacitance sensing system incorporating acquisition and measurement techniques using simultaneous acquisition codes and extended codes in accordance with an embodiment of the present disclosure;

[0010] Figure 4 A representative graph showing noise margin during operation of a capacitive sensing system incorporating acquisition and measurement techniques using simultaneous acquisition codes and extended codes according to an embodiment of the present disclosure;

[0011] Figure 5A A flow chart showing a capacitive sensing acquisition process of a merge-and-expand technique according to an embodiment of the present disclosure;

[0012] Figure 5B A flow chart showing a capacitive sensing acquisition process of a merge-and-expand technique according to an embodiment of the present disclosure;

[0013] Figure 6 A capacitive sensing system incorporating encoding and frequency extension techniques in acquisition and measurement according to an embodiment of the present disclosure is shown;

[0014] Fig. 7A A flow chart showing a capacitive sensing acquisition process combining coding and frequency extension techniques according to an embodiment of the present disclosure;

[0015] Figure 7B A flow chart showing a capacitive sensing acquisition process combining coding and frequency extension techniques according to an embodiment of the present disclosure;

[0016] Figure 8shows a representation of a force sensing operation according to an embodiment of the present disclosure; and

[0017] Fig.9A and Fig. 9B A capacitive sensing acquisition process according to the prior art is shown. DETAILED DESCRIPTION

[0018] In the following detailed description, reference is made to the accompanying drawings which form a part thereof, and in which specific exemplary embodiments in which the present disclosure may be practiced are shown by way of example. These embodiments are described in sufficient detail to enable one of ordinary skill in the art to practice the present disclosure. However, other embodiments may be utilized, and changes in structure, material, and process may be made without departing from the scope of the present disclosure.

[0019] The illustrations presented herein are not intended to be actual views of any particular method, system, device, or structure, but are merely idealized representations for describing embodiments of the present disclosure. The drawings presented herein are not necessarily drawn to scale. For the convenience of the reader, similar structures or components in the various drawings may retain the same or similar numbering; however, the similarity of numbering does not mean that the structures or components must be identical in size, composition, configuration, or any other attribute.

[0020] It is readily understood that the components of the embodiments as described herein as a whole and shown in the accompanying drawings may be arranged and designed in a variety of different configurations. Therefore, the following description of various embodiments is not intended to limit the scope of the present disclosure, but is merely representative of various embodiments. Although various aspects of the embodiments may be presented in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0021] The following description may include examples to help those skilled in the art practice the embodiments disclosed in the present invention. The use of the terms "exemplary", "by way of example" and "for example" means that the relevant description is illustrative, and although the scope of the present disclosure is intended to cover examples and legal equivalents, the use of such terms is not intended to limit the scope of the embodiments or the present disclosure to the specified components, steps, features or functions, etc.

[0022] Therefore, unless otherwise specified herein, the specific embodiments shown and described are merely examples and should not be construed as the only way to implement the present disclosure. Elements, circuits, and functions may be shown in block diagram form so as not to obscure the present disclosure with unnecessary details. On the contrary, the specific embodiments shown and described are merely exemplary and should not be construed as the only way to implement the present disclosure, unless otherwise specified herein. In addition, the partitioning of logic between block definitions and individual blocks is an example of a specific embodiment. It will be apparent to one of ordinary skill in the art that the present disclosure can be practiced through many other partitioning solutions. In most cases, details about timing considerations, etc. have been omitted, where such details are not required to obtain a complete understanding of the present disclosure and are within the capabilities of one of ordinary skill in the relevant art.

[0023] The information and signals described herein may be represented using any of a variety of different techniques and technologies. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout this specification may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof. For clarity of presentation and description, some of the accompanying drawings may show signals as single signals. It will be appreciated by those of ordinary skill in the art that a signal may represent a bus of signals, wherein the bus may have various bit widths, and the present disclosure may be implemented on any number of data signals including a single data signal.

[0024] It should be understood that any reference to an element using names such as "first", "second", etc. herein does not limit the number or order of these elements, unless such limitations are explicitly stated. On the contrary, these names are used herein as a convenient method to distinguish two or more elements or two or more instances of an element. Therefore, the reference to the first element and the second element does not mean that only two elements can be used, or that the first element must be before the second element in some way. Moreover, unless otherwise stated, a group of elements may include one or more elements. Similarly, an element sometimes mentioned in the singular may also include one or more instances of an element.

[0025] The various exemplary logic blocks, modules, and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed with a general purpose processor, a special purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof, designed to perform the functions described herein. A general purpose processor (also referred to herein as a host processor or simply a host) may be a microprocessor, but in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. A general purpose computer including a processor is considered a special purpose computer when the general purpose computer is configured to execute computing instructions (e.g., software code) associated with the embodiments disclosed herein.

[0026] Moreover, it should be noted that embodiments can be described according to processes depicted as flow charts, flow diagrams, structure diagrams, or block diagrams. Although flow charts can describe operational behaviors as sequential processes, many of these behaviors can be performed in another order, in parallel, or substantially simultaneously. In addition, the order of actions can be rearranged. A process can correspond to a method, a thread, a function, a program, a subroutine, a subprogram, etc. In addition, the methods disclosed herein can be implemented in hardware, software, or both. If implemented in software, these functions can be stored or transmitted to a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, and the communication media include any media that is conducive to transferring a computer program from one location to another.

[0027] As understood for the purposes of the embodiments described in this disclosure, a capacitive sensor can respond to an object (such as a finger or stylus) coming into contact with a touch-sensitive area of ​​the capacitive sensor or an object approaching a touch-sensitive area of ​​the capacitive sensor. In this disclosure, "contact" and "touch" are meant to encompass both physical contact of an object with a touch-sensitive area and the presence of an object within proximity of a touch-sensitive area without physical contact. Actual physical contact with the capacitive sensor is not required.

[0028] When an object contacts a capacitive sensor, a change in capacitance may occur at or near the contact location within the touch sensor. If the touch meets a certain threshold, the analog acquisition front end may "detect" the touch. "Charge-and-transfer" is a technique implemented in some touch acquisition front ends for detecting changes in capacitance, in which the sensing capacitor is charged (e.g., faster or slower) in response to the change in capacitance, and the charge is transferred to the integration capacitor over multiple charge transfer cycles. The amount of charge associated with this charge transfer may be converted to digital signals by an analog-to-digital converter (ADC), and a digital controller may process those digital signals to determine a measurement and whether an object has contacted the sensor.

[0029] Self-capacitance sensors are capacitive field sensors that detect / respond to changes in capacitance to ground. They are typically arranged in arrays of rows and columns that react independently to touch. As a non-limiting example, a self-capacitance sensor may include a circuit that employs a repeated charge-and-transfer cycle using a common integrated CMOS push-pull driver circuit with floating terminals. Mutual capacitance sensors are capacitive field sensors that detect / respond to changes in capacitance between two electrodes, a drive electrode and a sense electrode. The drive electrode and sense electrode pair form a capacitor at each intersection of the drive line and the sense line. Self-capacitance technology and mutual capacitance technology can be used for the same touch interface and complement each other, for example, self-capacitance can be used to confirm a touch detected using mutual capacitance.

[0030] The touch sensors may be overlapped in a 2-dimensional (2-D) arrangement for a 2-D touch-sensitive surface that may be incorporated into a touch-sensitive surface (e.g., a touch pad or a display screen) and may facilitate user interaction with an associated home appliance. An insulating protective layer (e.g., resin, glass, plastic, etc.) may be used to cover the touch sensors. As used herein, a "touch display" or "touch panel" is a display (such as a liquid crystal display (LCD), a thin film transistor (TFT) LCD, or a light emitting diode (LED) display) that incorporates a 2-D touch sensor.

[0031] Using the example of a touch screen (which uses a matrix sensor approach of a mutual capacitance sensor using charge transfer technology), the drive electrodes may extend in rows on one side of the substrate and the sensing electrodes may extend in columns on the other side of the substrate to define a "matrix" array of N×M nodes. Each node corresponds to the intersection between the conductive lines of the drive electrode and the conductive lines of the sensing electrode. The drive electrode drives all nodes in a given row at the same time, and the sensing electrode senses all nodes in a given column. The capacitive coupling (mutual capacitance) of the drive electrode and the sensing electrode at the node position, or the coupling (self-capacitance) of the sensing electrode to the ground, may be measured separately or both in response to a capacitance change indicating a touch event. For example, if a drive signal is applied to the drive electrode of row 2 and the sensing electrode of column 3 is active, the node position is: (row 2, column 3). The nodes may be scanned sequentially by different combinations of drive electrodes and sensing electrodes. In one mode, the drive electrodes may be driven sequentially, while the sensing electrodes are all monitored continuously. In another mode, each sensing electrode may be sampled sequentially.

[0032] Some touch interfaces incorporate force sensing. Such "force-sensitive" interfaces may include sensors incorporated into, for example, a display or touchpad to measure incremental differences in the distance between a surface and features beneath the surface. For example, the distance between a pair of electrodes may change when relative movement occurs, thereby providing a measurable capacitance and / or capacitance change. The capacitance change may be used to estimate the force applied to the "force-sensitive surface" in response to the magnitude of the capacitance change. The location of the applied force on the force-sensitive surface may also be estimated, for example in response to one or more locations of electrode pairs of a force sensor that registers a capacitance change and / or a touch sensor that is also integrated with the interface.

[0033] As non-limiting examples, a microcontroller, digital logic circuits, and / or configurable state machines may be implemented to control the drive electrodes and analyze the capacitive effects on the touch sensors and force sensors. An integrated circuit (IC) package including a microcontroller may provide input and output pins to communicate with a host; and firmware to perform techniques and operations, including those described herein in conjunction with various embodiments. Examples of microcontrollers that may be used with various embodiments of the present disclosure may include, for example, peripheral interface microcontrollers, ARM-based microcontrollers, and AVR-8 and 32-bit microcontrollers.

[0034] For example, the sensing electrodes of the capacitive sensor may be operatively coupled to an acquisition front end (e.g., a charge integrator) via a device I / O pin of a digital controller. The digital controller may be coupled to the acquisition front end via an ADC / DAC pin. The digital controller may include, for example, a state machine (a collection of adders, flip-flops, and multiplexers that may form a digital logic circuit) configured to identify a contact and information about the contact in response to a channel capacitance measurement.

[0035] In the present disclosure, "simultaneous acquisition" and "has been acquired simultaneously" mean that signals (analog or digital) indicating sensing signals from multiple (e.g., two or more) sensing channels of a capacitive sensor are acquired during the same acquisition cycle by analog circuits and / or digital logic circuits. The sensing signal can be, for example, a charge flow from a sensing channel of the capacitive sensor to a sampling circuit, a charge flow to a charge-to-voltage converter, or both. The measurable signal can be a voltage, a current, a resistance, a capacitance, or a combination thereof. The sensing signals from multiple sensor channels can be acquired at the same acquisition circuit or more than one acquisition circuit. The embodiments described in the present disclosure assume that the sensing signals are acquired at the same acquisition circuit, but as described above, this is not a requirement of the present disclosure. The use of the past tense "has been acquired" as in "has been acquired simultaneously" is not intended to require the completion of simultaneous acquisition, and may include any point in time or operation during simultaneous acquisition.

[0036] References to channel capacitance include both absolute channel capacitance and changes in channel capacitance.A channel capacitance measurement or capacitance measurement includes any value indicative of channel capacitance.

[0037] In the present disclosure, "spreading code" means an N-bit coded data stream at a data rate (i.e., a frequency that can also be characterized as a coding rate in this article). The coding rate is usually N times the data rate of the coded data. In the digital domain, each bit of the spreading code is a logical "0" or a logical "1". For example, an 8-bit spreading code can be "0101 0101". For consistency and ease of explanation, spreading codes are discussed in the digital domain, but they can also be analog signals with amplitude and frequency.

[0038] Some spreading codes may be orthogonal to other spreading codes, that is, the cross-correlation of two spreading codes is substantially zero (ie, they do not interfere with each other). One property of orthogonal spreading codes is that the dot product of the two spreading codes is zero.

[0039] A conventional capacitance measurement technique is to perform it channel by channel, such as Fig.9A As shown. For each cycle 904, measurements are made sequentially for each of the channels 902, one sensing channel at a time. Thus, channel 1 is measured in cycle 1, channel 2 is measured in cycle 2, channel 3 is measured in cycle 3, and channel 4 is measured in cycle 4. The channel-by-channel measurement is fast (4 channels in 4 cycles), but there is little built-in noise margin in the measurement process itself.

[0040] One technique for improving SNR is to average multiple measurements from each channel, such as Fig. 9BAs shown in Figure 1, channel 1 is measured 4 times, channel 2 is measured 4 times, and so on. For Gaussian noise, averaging the N measurements for each channel will result in an improvement in the SNR for each channel (which can also be characterized as a reduction in noise). However, as Fig. 9B As shown, the measurements are still made sequentially (i.e., channel by channel), and therefore the acquisition speed is slower than that of techniques that do not use averaging. Fig.9A Compared with the acquisition of 4 channels in 4 cycles, Fig. 9B The acquisition of 4 channels 912 in 16 cycles 914 is shown. Such long acquisition periods are not conducive to touch panel resolution speed. Describing the measurement of channels as "sequential" or in a certain order is not intended to mean that the channels are adjacent (or the sense lines are adjacent), nor is it intended to mean that the present disclosure requires the acquisition of sense signals in a particular order or that channel measurements be made in any order.

[0041] Some embodiments of the present disclosure as a whole relate to simultaneously collecting sensing signals at multiple sensor channels of a capacitive sensor and applying extended coding to the simultaneously collected sensing signals. The extended coded signals can be decoded and processed by a touch processor. Extending the collected signals improves the noise tolerance of the touch interface. Therefore, one or more embodiments of the present disclosure relate to a noise-tolerant touch acquisition system.

[0042] One advantage of acquiring sensor signals simultaneously and using extended coding is that it decouples the trade-off between resolution speed and SNR to varying degrees. In other words, given a single-channel acquisition system with a signal-to-noise ratio of SNR1, the signal-to-noise ratio of a system implementing N-channel acquisition according to an embodiment of the present disclosure will be SNR N =sqrt(N)*SNR1, which can also be characterized as a sqrt(N) reduction in noise. Thus, compared to a single-channel acquisition system, an 8-channel system implementing an embodiment of the present disclosure may have a signal-to-noise ratio of sqrt(8)*SNR1, but without a corresponding decrease in resolution speed, which can also be characterized as a reduction in refresh rate.

[0043] Furthermore, a capacitive sensing system incorporating the acquisition and / or measurement techniques of the present disclosure can achieve the same SNR performance as a single channel acquisition system, but with Number of channels. For example, a 16×16 channel touch panel incorporating capacitive sensing according to an embodiment of the present disclosure can achieve a refresh rate 16 times that of a 16×16 channel touch panel incorporating a single channel acquisition technique. In other words, a 16×16 channel touch panel incorporating a single channel acquisition technique has a 160 Hz refresh rate compared to a 10 Hz refresh rate of a 16×16 channel touch panel using a conventional single channel acquisition technique.

[0044] In various embodiments, the selected spreading codes are orthogonal to allow for better differentiation of the contributing sense signals into the accumulated signal. In other words, if there are three spreading codes, each spreading code is orthogonal to the other two spreading codes. Generally speaking, the number of spreading codes used will be the same as the number of channels of the touch sensor being collected simultaneously.

[0045] Figure 1 The operation of a capacitive sensor incorporating acquisition and measurement techniques according to one or more embodiments of the present disclosure is shown. In this example, sensing signals (e.g., charge) at channels 102 (i.e., Ch. 1 to Ch. 8) are simultaneously acquired over 8 acquisition cycles. In this example, there is no change in capacitance. Tx value 106 indicates baseline channel capacitance (e.g., no touch at the touch panel). Here, the charge on each channel indicates the magnitude of the drive signal supplied to the drive line.

[0046] During each acquisition cycle, each bit of the orthogonal spreading code 104 is applied to the channel 102. For example, the code "0000 0000" is applied to the sensed signal from Ch. 1, the code "0101 0101" is applied to Ch. 2, and so on, where each consecutive bit is applied during each acquisition cycle (from left to right). Therefore, when the code 104 of "0000 0000" is convolved with the Tx value 106 ("1") of Ch. 1 within eight acquisition cycles, the encoded Tx coded value 110 corresponding to Ch. 1 is "-1 -1 -1 -1 -1 -1 -1", and when the code "0101 0101" is convolved with the Tx value 106 ("1") of Ch. 2, the encoded Tx value 110 corresponding to Ch. 2 is "-1 1 -1 1 -1 1 -1 1", and so on.

[0047] Each bit in the encoded Tx value 110 of the channel represents a positive or negative contribution to the value accumulated at the acquisition circuit. Therefore, the contribution of the first bit 110a of the Tx value 110 to each channel can be accumulated as "-8" or (-1)+(-1)+(-1)+(-1)+(-1)+(-1)+(-1)=-8, and the contribution of the next bit 110b of the Tx word 110 to each channel can be accumulated as "0" or (-1)+(1)+(-1)+(-1)+(1)+(-1)+(1)=0, and so on. The encoded accumulated Tx value 108 finally transmitted to the digital controller is "-8 0 0 0 0 0 0 0".

[0048] The coded accumulated Tx values ​​108 may be decoded in response to the orthogonal spreading code 104 to obtain a coded intermediate value 114 for each sensed channel. Thus, the coded intermediate data 114 for Ch. 1 is "8 0 0 0 0 0 0 0", the coded intermediate value 114 for Ch. 2 is "8 0 0 0 0 0 0 0", and so on. A received value (Rx value) 116 may be decoded in response to the coded intermediate value 114 for each channel. In one or more embodiments, the Rx value 116 is determined by summing each entry of the coded intermediate value 114, e.g., the Rx value 116 for Ch. 1 is 8, the Rx value 116 for Ch. 2 is 8, and so on. By the predefined convention implemented in this example, "8" corresponds to a logical "1" and "-8" corresponds to a logical "0". Thus, in this example, an Rx value of 116 corresponds to "1111 1111," which is the same as a Tx value of 106, or using the touch example, no touch. One of ordinary skill in the art will appreciate that other conventions may be implemented.

[0049] Figure 2 A system diagram of an embodiment of a capacitance sensing system 200 according to one or more embodiments of the present disclosure is shown. The encoder 220 can be operatively coupled to the sensing channel 212 of the N-channel sensor 210, and can be configured to encode the sensing signal collected simultaneously at 1 to N sensing channels 212 (e.g., a modulated signal). In one or more embodiments, the encoder 220 may include N encoders, and each such encoder may be configured to encode the allocated channel of the N-channel sensor 210 in response to a spreading code. In one or more embodiments, the encoder 220 may be a digital logic circuit configured to implement the convolution of the spreading code with the sensing signal. In one or more embodiments, each spreading code may be implemented as a digital circuit. In another embodiment, a general digital circuit may be configured to implement convolution in response to one or more spreading codes.

[0050] The accumulator 230 may be operatively coupled to the encoder 220 and configured to receive the encoded 1 to N sensing signals. In one or more embodiments, the accumulator 230 may include a charge-to-voltage converter (not shown) configured to accumulate charge and output a voltage in response to the charge. In one or more embodiments, the accumulator 230 may include a charge-post-transfer circuit that accumulates charge at an integration capacitor and outputs a discrete voltage faster or slower in response to channel capacitance and / or channel capacitance changes.

[0051] Decoder 240 may be operatively coupled to accumulator 230. Decoder 240 may be configured to receive a spread coded analog or digital signal from accumulator 230 (e.g., coupled to an output of a charge-to-voltage converter, coupled to an output of an analog-to-digital converter, etc.), decode the received signal in response to one or more spread codes, and output a decoded signal. Decoder 240 may be configured to decode the coded accumulated signal and generate an encoded intermediate value indicating the contribution of each channel to the coded accumulated value. Each such encoded intermediate value for each channel may be generated within a continuous acquisition cycle.

[0052] In one or more embodiments, decoder 240 may be hardware or digital circuitry coupled to digital controller 250. In another embodiment, decoder 240 may be implemented in software, such as in software of digital controller 250.

[0053] In one or more embodiments, encoder 220, accumulator 230, and decoder 240 may form an acquisition circuit, such as a front-end acquisition circuit, for capacitive sensing system 200. In another embodiment, encoder 220 and accumulator 230 may form an acquisition circuit for capacitive sensing system 200, and decoder 240 may be implemented at digital controller 250 (e.g., in software).

[0054] The digital controller 250 may be operatively coupled to the decoder 240 and may be configured to determine channel capacitance measurements for one or more channels in response to the encoded intermediate values. In one or more embodiments, the digital controller 250 may include one or more touch processors (not shown) configured to determine touch information in response to the channel capacitance measurements. For example, the location (e.g., xy-location, pixel location, etc.) of a touch at a touch-sensitive surface (not shown) operatively coupled to the N-channel sensor 210. In one or more embodiments, the digital controller 250 may be configured to provide touch information to an interface (not shown) of a data bus (not shown), such as a universal asynchronous receiver-transmitter (UART), a universal synchronous / asynchronous receiver-transmitter USART, or an internal integrated circuit (I 2 C) In one or more embodiments, the data bus may be a peripheral data bus operatively coupled to a microcontroller, and one or more of the accumulator 230, encoder 220, and digital controller 250, along with the microcontroller, may be part of an integrated circuit package.

[0055] Figure 3An exemplary measurement that may be performed at a capacitive sensor system 200 according to one or more embodiments of the present disclosure is shown. In this example, charge from Ch. 4 is accumulated in response to channel capacitance changes. The channel capacitance is represented here as "3". The encoder 220 applies a spread code 302 of "0110 0110" to Ch. 4, and the result is a spread coded value 304 of "-3, 3, 3, -3, -3, 3, 3, -3". The spread coded value 304 is accumulated with spread coded values ​​associated with other channels, and the spread coded accumulated Tx value 306 is "-4, 4, 0, 0, -4, 4, 0, -8". The decoder 240 decodes the Tx value 306 in response to the spread code used to encode each channel, and constructs a spread coded intermediate value indicating the contribution of each channel to the accumulated value. The spread coded intermediate value 308 of Ch. 4 is "4, 4, 0, 0, 4, 4, 0, 8".

[0056] Digital controller 250 decodes each coded intermediate value it receives by summing the value of each bit of the intermediate coded value to determine the received value for each sensing channel. Here, the channel capacitance measurement value 310 for Ch. 4 determined in response to the intermediate coded value is "24".

[0057] In the case of a touch application, a touch processor (not shown) may be configured to compare the channel capacitance measurements for each channel to one or more thresholds and, in response to the comparison, determine touch information (e.g., if a touch occurred, the location where the touch occurred (e.g., x-coordinate and y-coordinate), the time when the touch occurred (e.g., a counter), and other touch information).

[0058] Figure 4 4 shows an example of the noise tolerance of the capacitance sensing system 200 according to one or more embodiments of the present disclosure. Here, noise 402 is transmitted with the coded accumulated Tx value 404. The noise 402 may be the result of unwanted capacitive coupling with other subsystems, power supplies, moisture, etc., which affects the measurement of the channel capacitance by the capacitance sensing system. Figure 4 As shown, the coded accumulated Tx value 404 does not exactly match the value that would be transmitted in a 100% noise immune capacitive sensing system due to noise 402. However, the measured value 406 of Ch. 4 determined by the digital controller 250 in response to the intermediate value 408 includes only a small amount of error (24 - 23.5 = .5) due to noise 402.

[0059] Figure 5AA flow chart of an acquisition process of a coded sensing channel using a capacitive sensing system according to an embodiment of the present disclosure is shown. In operation 502, a drive signal is asserted at a drive channel of a capacitive sensor. In one or more embodiments, the drive signal may indicate a sensing operation performed at the capacitive sensing system. The drive signal may be asserted for multiple acquisition cycles, which form a simultaneous acquisition period. In operation 504, a sensing signal at N sensing channels of the capacitive sensor is extended and encoded in response to an extension code. In one or more embodiments, a different N-bit extension code is applied to each sensing channel, and each extension code is orthogonal to other extension codes. In one or more embodiments, for each acquisition cycle, the sensing signal is extended on the bits of the available extension code. In operation 506, N extension code bits corresponding to different channels are accumulated. In operation 508, the current extension code accumulation bits are transmitted to, for example, a digital controller 250. In each acquisition cycle, the sensing signal is extended on the additional bits of the extension code until after a simultaneous acquisition period equivalent to the acquisition cycle, the sensing signal has been extended, accumulated and transmitted on the entire extension code.

[0060] Figure 5B A flow chart of a process for decoding an extended coded sensing signal and using the decoded signal to determine a channel capacitance measurement value according to an embodiment of the present disclosure is shown. In operation 512, an extended coded accumulated value is received. In operation 514, the extended coded accumulated value is decoded in response to the extended code. In operation 516, the encoded intermediate value of each channel is determined in response to the decoding. In one or more embodiments, a decoding operation is applied, which is logically opposite to the coding sequence applied at each channel to encode the transmission value in order to obtain each intermediate value. In operation 518, the intermediate value is further decoded for at least one channel. In one or more embodiments, each bit of the encoded intermediate value is summed with other bits. In operation 520, the channel capacitance measurement value is determined in response to the decoding.

[0061] Noise can also be introduced into the drive or sense lines of a capacitive sensing system. Therefore, in some embodiments of the present disclosure, the drive signal is encoded and modulated at multiple frequencies using an orthogonal spreading code, and the coded and frequency spread drive signal is then used to drive the drive line. The de-expander and decoder demodulate and decode the sense signal before it is transmitted to the digital controller.

[0062] Figure 6A capacitive sensing system incorporating spread coding according to one or more embodiments of the present disclosure is shown. Capacitive sensing system 600 includes an encoder 610, a code expander 620, and a surface having a drive channel 630 on the drive side. Encoder 610 can be configured to encode drive signal 602 in response to the spread code. For each acquisition cycle, encoder 610 can be configured to encode the drive signal of the channel with additional bits of the available spread code. Code expander 620 can be operatively coupled to encoder 610 and configured to respond to a transmission frequency associated with the channel (e.g., Fx, 1 / 2Fx, 1 / 4Fx, etc.) to modulate each extended coded driving signal. For example, the code expander 620 may expand "1010" to "1010" in response to the Fx transmission frequency, 1 / 2Fx transmission frequency and expands "1010" to "1111 0000 1111 0000", and responds to 1 / 4Fx transmission frequency to expand "1010" to "1111 1111 0000 0000 1111 1111 000000000". Code expander 620 may be operatively coupled to a drive channel of the surface via drive channel 630 and configured such that coded and frequency expanded drive signals may be asserted at the drive channel.

[0063] The sensing side of the capacitance sensing system 600 includes a sensor having Y sensing channels 640, an acquisition circuit 650, a de-expander 660, a decoder 670, and a digital controller 680. In one or more embodiments, the decoder 670 can be part of the digital controller 680, such as a process executed in firmware or circuit. The acquisition circuit 650 can be operatively coupled to the sensing channels 640 and configured to simultaneously acquire sensing signals from the sensing channels 640, including signals indicating channel capacitance and changes in channel capacitance. The de-expander 660 can be operatively coupled to the acquisition circuit 650 and configured to frequency demodulate the coded and spread sensing signals accumulated at the acquisition circuit 650. The de-expander 660 can be operatively coupled to the decoder 670, and the decoder 670 can be configured to decode the coded accumulated signal in response to the orthogonal spreading code used to encode the drive line. The result of the decoding can be the coded intermediate value or data for each channel. Decoder 670 may be configured to further decode the intermediate values ​​and determine a value indicative of a channel capacitance of each sensing channel of sensing channel 640. Digital controller 680 may be configured to further process the channel capacitance values ​​and determine touch information, for example, in response to the channel capacitance values.

[0064] Although the acquisition circuit 650, despreader 660, and decoder 670 are described as separate units, in one or more embodiments, the despreader 660, decoder 670, and accumulator (not shown) may together form the acquisition circuit 650. One or more embodiments may implement analog-to-digital (ADC) conversion at different stages (e.g., after charge accumulation, after despreading, or after decoding). Additionally, in one or more embodiments, one or more of the despreader 660 and the decoder 670 may be implemented at the digital controller 680 (e.g., in software executed by a microprocessor).

[0065] In one or more embodiments, one or more of the despreader 660, decoder 670, and digital controller 680 may be implemented as part of a microcontroller having a memory, a microprocessor, input / output ports, and optionally one or more peripherals. In another embodiment, one or more of the despreader 660, decoder 670, and digital controller 680 may be implemented as a hardware circuit or digital circuit of a peripheral, or as software if the peripheral is implemented at a microprocessor.

[0066] Fig. 7A A flow chart of a coding drive process 700 for encoding a sensing channel of a capacitive sensing system according to an embodiment of the present disclosure is shown. In operation 702, a drive signal is extended and encoded in response to an extension code. In one or more embodiments, each drive signal is configured to be asserted at a different drive channel of a capacitive sensor. A different N-bit extension code is applied to each drive signal, and each extension code is orthogonal to other extension codes. In one or more embodiments, for each acquisition cycle, the drive signal is extended on the bits of the available extension code. Information about one or more acquisition cycles on which the drive signal will be extended and encoded can be provided. In operation 704, the drive signal is frequency extended in response to a transmission frequency associated with the drive channel. In operation 706, an encoding and frequency extended drive signal is asserted at a drive channel of a capacitive sensor. In operation 708, the sensing signals from the sensing channels of the capacitive sensor are accumulated.

[0067] Figure 7B FIG. 7 is a flow chart of an extended acquisition process 710 for decoding an accumulated sense signal generated in response to a frequency extended and encoded drive signal and using the result to determine a channel capacitance measurement value according to an embodiment of the present disclosure. In operation 712, a frequency extended encoded accumulated sense signal is received. It is worth noting that due to the frequency extension, it can take N*f ratio To receive all accumulated sensing signals, where f ratiois the ratio of the maximum extended signal to the unit signal (i.e., 1, 2, 4, etc.). In operation 714, the accumulated sensing signal is demodulated (which may also be characterized as "de-spreading" in the present disclosure). In one or more embodiments, the accumulated sensing signal may be converted to a digital signal before being demodulated. In operation 716, a first decoding of the demodulated sensing signal is performed in response to the spreading code used to encode the drive signal. In one or more embodiments, a coded intermediate value is generated in response to a decoding operation applied to the accumulated sensing signal, wherein the decoding operation may be logically opposite to the coding sequence applied at each channel to encode the drive signal. In operation 718, a coded intermediate signal is determined in response to the first decoding. In operation 720, another decoding of the intermediate data of at least one channel is performed. In one or more embodiments, other decoding may include bit summing of the intermediate data. In operation 722, a channel capacitance measurement value of at least one channel is determined in response to the second decoding.

[0068] Embodiments of the capacitive sensing systems described in this disclosure may be incorporated into a touch interface configured to perform touch processing and force processing. Figure 8 Force sensing in a noise tolerant touch interface according to an embodiment of the present disclosure is shown.A pressure measurement 802 (ie, force) is determined by further processing the capacitance measurement based on the sense signal.

[0069] Those of ordinary skill in the art will appreciate that embodiments of the present disclosure may be applicable to more than just converting capacitance changes to voltage, for example, the same principles apply to using charge changes to determine frequency and using charge changes to determine current. Thus, touch embodiments of the present disclosure are not limited to touch controllers that measure voltage to detect contact, but are also applicable to touch controllers that measure frequency and current (or changes in frequency and / or current).

[0070] Those skilled in the art will recognize that, in addition to overcoming the deficiencies of some conventional acquisition techniques, the embodiments of the present disclosure have many benefits and advantages. For example, the embodiments may achieve improved resolution speeds compared to conventional acquisition techniques, and thus be able to resolve larger panels within the same time constraints as conventional acquisition techniques; achieve improved signal-to-noise ratios and thus operate at the same resolution speeds achieved by conventional single-channel acquisition, but with greater noise immunity; and achieve improved power savings, as faster operation allows the device to be used for shorter periods of time and consume less power over time.

[0071] Many functional descriptions in this specification may be shown, described or labeled as modules, threads, steps or other classifications of programming code (including firmware) to more specifically emphasize their implementation independence. Modules may be implemented in hardware at least in part in one or another form. For example, a module may be implemented as a hardware circuit that includes a customized VLSI circuit or gate array, an existing semiconductor such as a logic chip, a transistor or other discrete component. Modules may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic units, programmable logic devices, etc.

[0072] Modules may also be implemented using software or firmware stored on a physical storage device (eg, a computer-readable storage medium), in memory, or a combination thereof for execution by various types of processors.

[0073] The identified module of executable code may, for example, include one or more physical blocks or logical blocks of computer instructions, which may, for example, be organized as threads, objects, procedures, or functions. However, the executable files of the identified modules need not be physically located together, but may include different instructions stored in different locations, which, when logically joined together, comprise the module and achieve the stated purpose of the module.

[0074] In fact, the module of executable code can be a single instruction or many instructions, and can even be distributed on several different code segments, between different programs and on several storage devices or memory devices. Similarly, operating data can be identified and shown in this article within the module, and can be implemented in any suitable form and organized in any suitable type of data structure. Operating data can be collected as a single data set, or can be distributed in different locations, including distribution on different storage devices, and can exist at least partially as electronic signals on a system or network. In the case where a module or part of a module is implemented in software, the software portion is stored on one or more physical devices, which are referred to as computer-readable media in this article.

[0075] In some embodiments, the software part is stored in a non-transient state so that the software part or its representation continues for a period of time at the same physical location. In addition, in some embodiments, the software part is stored on one or more non-transient storage devices, which include hardware elements capable of storing non-transient states and / or signals representing the software part, although other parts of the non-transient storage device may be able to change and / or transmit signals. Examples of non-transient storage devices are flash memory and random access memory (RAM). Another example of non-transient storage device includes a read-only memory (ROM), which can store signals and / or states representing the software part for a period of time. However, the ability to store signals and / or states will not be weakened by transmitting other functions of signals that are identical to or represent stored signals and / or states. For example, a processor can access a ROM to obtain a signal representing a stored signal and / or state in order to execute corresponding software instructions.

[0076] Additional non-limiting embodiments of the present disclosure include:

[0077] Embodiment 1: A capacitance sensing system comprises: a sensor circuit, the sensor circuit including a sensing line; an acquisition circuit, the acquisition circuit operatively coupled to the sensing line, wherein the acquisition circuit is configured to receive a sensing signal indicating one or more capacitances at the sensor circuit and provide an accumulated separate sensing signal in response to the sensing signal; and a digital controller, the digital controller is operatively coupled to the acquisition circuit and is configured to determine a channel capacitance measurement value in response to the accumulated separate sensing signal.

[0078] Embodiment 2: The system according to embodiment 1, wherein the acquisition circuit is configured to: receive the sensing signal at the sensing line; separate the sensing signal; and accumulate the separated sensing signals.

[0079] Embodiment 3: The system according to any of the preceding embodiments, wherein the acquisition circuit is configured to separate the sensed signal by spreading the sensed signal in response to one or more spreading codes.

[0080] Embodiment 4: A system according to any of the preceding embodiments, wherein at least one of the one or more spreading codes is a binary code comprising two or more bits.

[0081] Embodiment 5: The system according to any of the preceding embodiments, wherein the acquisition circuit is configured to receive the sensing signal during an acquisition period, the acquisition period comprising two or more acquisition cycles.

[0082] Embodiment 6: A system according to any of the preceding embodiments, wherein the sensing line includes a first sensing line, and the acquisition circuit is configured to: receive a first sensing signal among the sensing signals at the first sensing line during an acquisition period; expand the first sensing signal in response to a first expansion code during a first acquisition cycle in the acquisition period; and expand the first sensing signal in response to the first expansion code during a second acquisition cycle in the acquisition period.

[0083] Embodiment 7: A system according to any one of the preceding embodiments, wherein the first spread code includes at least a first bit and a second bit, and the acquisition circuit is configured to: convolve the first sensing signal in the first sensing signal with the first bit of the first spread code; and convolve the second sensing signal in the first sensing signal with the second bit of the first spread code.

[0084] Embodiment 8: A system according to any of the preceding embodiments, wherein the acquisition circuit is configured to: during the first acquisition period, convolve the first sensing signal in the first sensing signal with the first bit of the first extension code; and during the second acquisition period, convolve the second sensing signal in the first sensing signal with the second bit of the first extension code.

[0085] Embodiment 9: A system according to any of the preceding embodiments, wherein the sensing line includes a second sensing line, and the acquisition circuit is configured to: receive a second sensing signal in the sensing signal at the first sensing line during the acquisition period; expand the second sensing signal in response to a second expansion code during the first acquisition cycle in the acquisition period; and expand the second sensing signal in response to the second expansion code during the second acquisition cycle in the acquisition period.

[0086] Embodiment 10: A system according to any one of the preceding embodiments, wherein the second spread code includes at least a first bit and a second bit, and the acquisition circuit is configured to: convolve the first sensing signal in the second sensing signal with the first bit of the second spread code; and convolve the second sensing signal in the second sensing signal with the second bit of the second spread code.

[0087] Embodiment 11: A system according to any one of the preceding embodiments, wherein the second spread code includes at least a first bit and a second bit, and the acquisition circuit is configured to: during the first acquisition period, convolve the first sensing signal in the second sensing signal with the first bit of the second spread code; and during the second acquisition period, convolve the second sensing signal in the second sensing signal with the second bit of the second spread code.

[0088] Embodiment 12: A system according to any of the preceding embodiments, wherein the sensing line includes a first sensing line and a second sensing line, and the acquisition circuit is configured to: receive a first sensing signal at the first sensing line and receive a second sensing signal at the second sensing line; expand the first sensing signal in response to a first spreading code among the one or more spreading codes; expand the second sensing signal in response to a second spreading code among the one or more spreading codes; and accumulate the expanded first sensing signal and the expanded second sensing signal.

[0089] Embodiment 13: The system of any of the preceding embodiments, wherein the digital controller is configured to differentiate the accumulated split sense signal in response to the one or more spreading codes.

[0090] Embodiment 14: A system according to any of the preceding embodiments, wherein the digital controller is configured to determine touch information in response to the channel capacitance measurement value.

[0091] Embodiment 15: A system according to any of the preceding embodiments, wherein the digital controller is configured to provide the one or more extension codes.

[0092] Embodiment 16: A system according to any of the preceding embodiments, wherein the one or more extension codes include a digital logic circuit configured to receive a sensing signal and acquisition period information and provide an extended sensing signal.

[0093] Embodiment 17: A method for collecting sensing signals from a capacitive sensor, comprising: receiving one or more sensing signals at one or more sensor channels associated with the capacitive sensor; separating the one or more sensing signals; and accumulating one or more separated sensing signals.

[0094] Embodiment 18: The method according to any of the preceding embodiments, wherein separating the one or more sensed signals comprises spreading the sensed signals in response to one or more spreading codes.

[0095] Embodiment 19: A method according to any of the preceding embodiments, wherein at least one of the one or more spreading codes is a binary code comprising two or more bits.

[0096] Embodiment 20: The method according to any of the preceding embodiments further comprises receiving the sensing signal during an acquisition period, the acquisition period comprising two or more acquisition cycles.

[0097] Embodiment 21: According to the method described in any one of the preceding embodiments, it also includes: during an acquisition period, receiving a first sensing signal in the sensing signal at a first sensing line in the sensing line; during a first acquisition cycle in the acquisition period, expanding the first sensing signal in response to a first extension code; and during a second acquisition cycle in the acquisition period, expanding the first sensing signal in response to the first extension code.

[0098] Embodiment 22: The method according to any one of the preceding embodiments further includes: convolving the first sensing signal in the first sensing signal with the first bit of the first extension code; and convolving the second sensing signal in the first sensing signal with the second bit of the first extension code.

[0099] Embodiment 23: According to the method described in any one of the preceding embodiments, it also includes: during the acquisition period, receiving a second sensing signal in the sensing signal at a second sensing line in the sensing line; during the first acquisition cycle in the acquisition period, expanding the second sensing signal in response to a second extension code; and during the second acquisition cycle in the acquisition period, expanding the second sensing signal in response to the second extension code.

[0100] Embodiment 24: The method according to any one of the preceding embodiments further includes: convolving the first sensing signal in the second sensing signal with the first bit of the second extension code; and convolving the second sensing signal in the second sensing signal with the second bit of the second extension code.

[0101] Embodiment 25: According to the method described in any of the foregoing embodiments, it also includes: receiving a first sensing signal at a first sensing line among the sensing lines, and receiving a second sensing signal at a second sensing line among the sensing lines; expanding the first sensing signal in response to a first spreading code among the one or more spreading codes; expanding the second sensing signal in response to a second spreading code among the one or more spreading codes; and accumulating the expanded first sensing signal and the expanded second sensing signal.

[0102] Embodiment 26: The method according to any of the preceding embodiments further includes differentiating the accumulated separated sensing signals in response to the one or more spreading codes.

[0103] Embodiment 27: The method according to any of the preceding embodiments further includes determining at least one channel capacitance measurement value in response to the one or more separate sensing signals.

[0104] Embodiment 28: The method of any of the preceding embodiments further comprises determining touch information in response to the at least one channel capacitance measurement.

[0105] Embodiment 29: The method according to any of the preceding embodiments further includes: differentiating the accumulated separation sensing signal in response to the one or more spread codes; integrating one or more individual separation sensing signals; and determining one or more capacitance channel measurement values ​​in response to the integrated sensing signal.

[0106] Embodiment 30: The method of any preceding embodiment, wherein each spreading code is associated with one of the one or more sensor lines.

[0107] Embodiment 31: A digital controller for capacitive sensing, the controller comprising: a decoder configured to: differentiate an accumulated sensing signal in response to one or more spreading codes; and integrate the differentiated separated sensing signal, and a processor configured to determine one or more capacitive channel measurement values ​​in response to the integrated sensing signal.

[0108] Embodiment 32: A digital controller according to any of the preceding embodiments, wherein the decoder is configured to determine a first differential separation sensing signal in the differential separation sensing signal in response to a first spread code in the one or more spread codes and the accumulated sensing signal.

[0109] Embodiment 33: A controller according to any of the preceding embodiments, wherein the first differential separation sensing signal includes at least two intermediate values, and the decoder is configured to integrate the first differential separation sensing signal by adding the at least two intermediate values.

[0110] Embodiment 34: A controller according to any of the preceding embodiments, wherein the decoder is configured to determine a second differential separation sensing signal in the differential separation sensing signal in response to a second spread code in the one or more spread codes and the accumulated sensing signal.

[0111] Embodiment 35: A controller according to any of the preceding embodiments, wherein the second differential separation sensing signal includes at least two intermediate values, and the decoder is configured to integrate the second differential separation sensing signal by adding the at least two intermediate values.

[0112] Embodiment 36: A controller according to any of the preceding embodiments, wherein the processor is configured to determine touch information in response to the one or more capacitive channel measurements.

[0113] Embodiment 37: A controller according to any of the preceding embodiments, wherein the processor is configured to provide the one or more spreading codes to the acquisition circuit.

[0114] Embodiment 38: A method for controlling capacitance sensing, the controller comprising: differentiating an accumulated sensing signal in response to one or more spreading codes; integrating the differentiated separated sensing signal, and determining one or more capacitance channel measurement values ​​in response to the integrated sensing signal.

[0115] Embodiment 39: The method according to any of the preceding embodiments further includes determining a first differential separation sensing signal in the differential separation sensing signal in response to a first spreading code in the one or more spreading codes and the accumulated sensing signal.

[0116] Embodiment 40: The method according to any one of the preceding embodiments, wherein the first differential separation sensing signal includes at least two intermediate values, and the method further includes integrating the first differential separation sensing signal by adding the at least two intermediate values.

[0117] Embodiment 41: The method according to any of the preceding embodiments further includes determining a second differential separation sensing signal in the differential separation sensing signal in response to a second spreading code in the one or more spreading codes and the accumulated sensing signal.

[0118] Embodiment 42: The method according to any of the preceding embodiments, wherein the second differential sensing signal includes at least two intermediate values, and the method further includes integrating the second differential separation sensing signal by adding the at least two intermediate values.

[0119] Embodiment 43: The method according to any of the preceding embodiments further includes determining touch information in response to the one or more capacitance channel measurements.

[0120] Embodiment 44: The method according to any of the preceding embodiments further includes providing the one or more extension codes.

[0121] Embodiment 45: A capacitance sensing system comprises: a sensor circuit, the sensor circuit comprising a sensing line and a drive line; an encoder, the encoder being configured to provide an encoded drive signal in response to one or more spreading codes; a frequency expander, the frequency expander being configured to provide a modulated drive signal in response to one or more transmission frequencies and one or more encoded drive signals; an acquisition circuit, the acquisition circuit being configured to provide an accumulated signal in response to one or more sensing signals; a frequency deexpander, the frequency deexpander being configured to provide a demodulated signal in response to one or more accumulated signals; a decoder, the decoder being configured to provide a differential signal in response to one or more demodulated signals; and a digital logic component, the digital logic component being configured to provide a channel capacitance measurement value in response to one or more differential signals.

[0122] Embodiment 46: A system according to any of the preceding embodiments, wherein at least one of the one or more spreading codes is a binary code comprising two or more bits.

[0123] Embodiment 47: A system according to any of the preceding embodiments, wherein the encoder is configured to expand the drive signal in response to the one or more expansion codes.

[0124] Embodiment 48: A system according to any of the preceding embodiments, wherein the encoder is configured to spread the drive signal in response to a first spreading code and to spread the drive signal in response to a second spreading code.

[0125] Embodiment 49: A system according to any of the preceding embodiments, wherein the frequency extender is configured to modulate the first coded drive signal in response to the first transmission frequency.

[0126] Embodiment 50: A system according to any of the preceding embodiments, wherein the frequency extender is configured to modulate the second coded drive signal in response to the second transmission frequency.

[0127] Embodiment 51: A system according to any of the preceding embodiments, wherein the encoder is configured to provide the encoded drive signal during an acquisition period, and the frequency expander is configured to provide the modulated drive signal during the acquisition period, wherein the acquisition period includes one or more acquisition cycles.

[0128] Embodiment 52: A system according to any of the preceding embodiments, wherein the encoder is configured to provide a first encoded drive signal during a first acquisition cycle in the acquisition period, and the frequency expander is configured to provide a first modulated drive signal during the first acquisition cycle.

[0129] Embodiment 53: A system according to any of the preceding embodiments, wherein the encoder is configured to provide a second encoded drive signal during a second acquisition cycle in the acquisition period, and the frequency expander is configured to provide the second modulated drive signal during the second acquisition cycle, wherein the second acquisition cycle is after the first acquisition cycle.

[0130] Embodiment 54: A system according to any of the preceding embodiments, wherein the encoder is configured to provide a first encoded drive signal in the encoded drive signal in response to a first spread code in the one or more spread codes, and to provide a second encoded drive signal in the encoded drive signal in response to a second spread code in the one or more spread codes.

[0131] Embodiment 55: A system according to any of the preceding embodiments, wherein the encoder is configured to provide the first encoded drive signal and the second encoded drive signal during the same acquisition period.

[0132] Embodiment 56: A system according to any of the preceding embodiments, wherein the frequency expander is configured to provide a first modulated drive signal in the modulated drive signal in response to a first frequency transmission in the one or more frequency transmissions, and to provide a second modulated drive signal in the modulated drive signal in response to a second frequency transmission in the one or more frequency transmissions.

[0133] Embodiment 57: The system of any of the preceding embodiments, wherein the frequency extender is configured to provide the first modulated drive signal and the second modulated drive signal during the same acquisition period.

[0134] Embodiment 58: A system according to any of the preceding embodiments, wherein the sensor circuit is configured to receive the modulated drive signal at a drive line.

[0135] Embodiment 59: A system according to any of the preceding embodiments, wherein the sensor circuit is configured to receive a first modulated drive signal at a first drive line and to receive a second modulated drive signal at a second drive line, wherein the first modulated drive signal has a first frequency and the second modulated drive signal has a second frequency.

[0136] Embodiment 60: A system according to any of the preceding embodiments, wherein the sensor circuit is configured to provide the sensing signal at one or more sensing lines.

[0137] Embodiment 61: A system according to any of the preceding embodiments, wherein the sensed signal is indicative of one or more capacitances at the sensor circuit.

[0138] Embodiment 62: The system of any of the preceding embodiments, wherein the acquisition circuit is configured to accumulate the sensing signal, wherein the sensing signal is received at the sensing line.

[0139] Embodiment 63: A system according to any of the preceding embodiments, wherein the frequency despreader is configured to demodulate the accumulated signal in response to the one or more transmission frequencies.

[0140] Embodiment 64: A system according to any of the preceding embodiments, wherein the decoder is configured to differentiate the demodulated signal in response to the one or more spreading codes.

[0141] Embodiment 65: A system according to any of the preceding embodiments, wherein a first differential signal among the one or more differential signals includes at least two intermediate values, and the digital logic component is configured to integrate the first differential signal by summing the at least two differential values.

[0142] Embodiment 66: A system according to any of the preceding embodiments, wherein the digital logic component is configured to determine touch information in response to the channel capacitance measurement value.

[0143] Embodiment 67: A system according to any of the preceding embodiments, wherein the digital logic component is configured to provide the one or more extension codes.

[0144] Embodiment 68: A system according to any of the preceding embodiments, wherein the one or more spreading codes include a digital logic circuit configured to receive a drive signal and acquisition cycle information and provide an encoded drive signal.

[0145] Embodiment 69: A method for sensing the channel capacitance of a sensor circuit, the method comprising: encoding a drive signal in response to one or more spreading codes; modulating the coded drive signal in response to one or more transmission frequencies and one or more coded drive signals; providing the modulated coded drive signal at the drive line of the sensor circuit; collecting a sensing signal at the sensing line of the sensor circuit; demodulating the sensing signal in response to the one or more transmission frequencies; decoding the demodulated sensing signal in response to the one or more spreading codes; and measuring the channel capacitance of the sensor circuit in response to the one or more demodulated sensing signals.

[0146] Embodiment 70: The method according to any of the preceding embodiments further includes at least one of the one or more extension codes being a binary code comprising two or more bits.

[0147] Embodiment 71: The method according to any of the preceding embodiments further includes encoding the drive signal in response to the first spreading code, and encoding the drive signal in response to the second spreading code.

[0148] Embodiment 72: The method according to any of the preceding embodiments further includes modulating the first coded drive signal in response to the first transmission frequency.

[0149] Embodiment 73: The method according to any of the preceding embodiments further includes modulating the second coded drive signal in response to a second transmission frequency.

[0150] Embodiment 74: The method according to any of the preceding embodiments further includes providing the encoded drive signal during an acquisition period, and providing the modulated drive signal during the acquisition period, wherein the acquisition period includes one or more acquisition cycles.

[0151] Embodiment 75: The method according to any of the preceding embodiments further includes providing a first coded drive signal during a first acquisition cycle in the acquisition period, and providing a first modulated drive signal during the first acquisition cycle.

[0152] Embodiment 76: The method according to any of the preceding embodiments further includes providing a second coded drive signal during a second acquisition cycle in the acquisition period, and providing the second modulated drive signal during the second acquisition cycle, wherein the second acquisition cycle is after the first acquisition cycle.

[0153] Embodiment 77: According to the method described in any of the foregoing embodiments, it also includes providing a first coded drive signal in the coded drive signal in response to a first spread code in the one or more spread codes, and providing a second coded drive signal in the coded drive signal in response to a second spread code in the one or more spread codes.

[0154] Embodiment 78: The method according to any of the preceding embodiments further includes providing the first encoded drive signal and the second encoded drive signal during the same acquisition period.

[0155] Embodiment 79: The method according to any one of the preceding embodiments further includes providing a first modulated drive signal in the modulated drive signal in response to a first frequency transmission in the one or more frequency transmissions, and providing a second modulated drive signal in the modulated drive signal in response to a second frequency transmission in the one or more frequency transmissions.

[0156] Embodiment 80: The method according to any of the preceding embodiments further includes providing the first modulated drive signal and the second modulated drive signal during the same acquisition period.

[0157] Embodiment 81: The method according to any of the preceding embodiments further includes receiving the modulated drive signal at a drive line.

[0158] Embodiment 82: The method according to any of the preceding embodiments further includes receiving a first modulated drive signal at a first drive line, and receiving a second modulated drive signal at a second drive line, wherein the first modulated drive signal has a first frequency and the second modulated drive signal has a second frequency.

[0159] Embodiment 83: The method according to any of the preceding embodiments further includes providing the sensing signal at one or more sensing lines.

[0160] Embodiment 84: A method according to any of the preceding embodiments, wherein the sensing signal is indicative of one or more capacitances at the sensor circuit.

[0161] Embodiment 85: The method according to any of the preceding embodiments further includes accumulating the sensing signal, wherein the sensing signal is received at the sensing line.

[0162] Embodiment 86: The method according to any of the preceding embodiments further includes demodulating the accumulated signal in response to the one or more transmission frequencies.

[0163] Embodiment 87: The method according to any of the preceding embodiments further includes differentiating the demodulated signal in response to the one or more spreading codes.

[0164] Embodiment 88: A method according to any of the preceding embodiments, wherein a first differential signal among the one or more differential signals includes at least two intermediate values.

[0165] Embodiment 89: The method according to any of the preceding embodiments further includes summing the at least two differential values.

[0166] Embodiment 90: The method according to any of the preceding embodiments further includes determining touch information in response to the channel capacitance measurement value.

[0167] Embodiment 91: The method according to any of the preceding embodiments further includes providing the one or more extension codes.

[0168] Embodiment 92: A method according to any of the preceding embodiments, wherein the one or more spreading codes include a digital logic circuit configured to receive a drive signal and acquisition cycle information and provide an encoded drive signal.

[0169] Embodiment 93: A digital controller for capacitance sensing, the controller comprising digital logic circuitry configured to provide channel capacitance measurements in response to one or more differentiated signals.

[0170] Embodiment 94: A digital controller according to any of the preceding embodiments, further comprising an encoder configured to provide an encoded drive signal in response to one or more spreading codes.

[0171] Embodiment 95: According to any of the preceding embodiments, the digital controller also includes a frequency expander, which is configured to provide a modulated drive signal in response to one or more transmission frequencies and one or more encoded drive signals.

[0172] Embodiment 96: According to any of the preceding embodiments, the digital controller further includes a frequency despreader configured to provide a demodulated signal in response to one or more accumulated signals.

[0173] Embodiment 97: A digital controller according to any of the preceding embodiments, further comprising a decoder configured to provide a differential signal in response to one or more demodulated signals.

[0174] Embodiment 98: A control method according to any of the preceding embodiments, comprising providing channel capacitance measurements in response to one or more differential signals.

[0175] Embodiment 99: According to any of the preceding embodiments, the capacitance sensing method includes: receiving one or more encoded and frequency-extended drive signals at one or more drive lines of the capacitance sensor; and providing one or more sensing signals in response to the one or more encoded and frequency-extended drive signals.

[0176] Although the present invention is described herein with respect to certain illustrated embodiments, those of ordinary skill in the art will recognize and appreciate that the present invention is not so limited. Rather, many additions, deletions, and modifications may be made to the illustrated embodiments and the described embodiments without departing from the scope of the present invention as claimed below and its legal equivalents. Furthermore, features from one embodiment may be combined with features of another embodiment while still being included within the scope of the present invention as contemplated by the inventor.

Claims

1. A system for capacitive sensing, comprising: a sensor circuit, the sensor circuit comprising a sensing line and a sensor channel; an acquisition circuit operatively coupled to the sensor channel, wherein the acquisition circuit: receiving a sense signal from the sensor channel, the sense signal being indicative of one or more capacitances at the sensor circuit, and providing an accumulated spread-encoded sense signal in response to the received sense signal; The acquisition circuit described herein: spreading encoding each of the received sensing signals for each channel by applying mutually orthogonal spreading codes, wherein each bit of the spreading code is one of a logic zero or a logic one; as well as accumulating spread coded values ​​for each channel in response to one or more orthogonal spreading codes used to encode each channel; and A digital controller is operatively coupled to the acquisition circuit and determines a channel capacitance measurement in response to the accumulated spread encoded values.

2. The system of claim 1, wherein at least one of the mutually orthogonal spreading codes is a code comprising two or more bits. 3 . The system of claim 1 , wherein the acquisition circuit receives the sensing signal during an acquisition period, the acquisition period comprising two or more acquisition cycles.

4. The system of claim 3, wherein the sensing line comprises a first sensing line, and the acquisition circuit: During an acquisition period, receiving a first sensing signal among the sensing signals at the first sensing line; as well as spreading the first sensing signal in response to a first spreading code during a first acquisition cycle in the acquisition period; as well as The first sensing signal is spread in response to the first spreading code during a second acquisition cycle in the acquisition period.

5. The system according to claim 4, wherein the first spreading code comprises at least a first bit and a second bit, and the acquisition circuit: convolving a first one of the first sensing signals with the first bit of the first spreading code; and A second one of the first sensing signals is convolved with the second bit of the first spreading code.

6. The system according to claim 5, wherein the acquisition circuit: during a first acquisition period, convolving the first of the first sensing signals with the first bit of the first spreading code; and During a second acquisition period, the second one of the first sensing signals is convolved with the second bit of the first spreading code.

7. The system of claim 4, wherein the sensing line comprises a second sensing line, and the acquisition circuit: During the acquisition period, receiving a second sensing signal among the sensing signals at the second sensing line; spreading the second sensing signal in response to a second spreading code during the first acquisition cycle in the acquisition period; as well as The second sensing signal is spread in response to the second spreading code during the second acquisition cycle in the acquisition period.

8. The system according to claim 7, wherein the second spreading code comprises at least a first bit and a second bit, and the acquisition circuit: convolving a first one of the second sensing signals with the first bit of the second spreading code; and A second one of the second sensing signals is convolved with the second bit of the second spreading code.

9. The system according to claim 7, wherein the second extension code comprises at least a first bit and a second bit, and the acquisition circuit: during the first acquisition cycle in the acquisition period, convolving a first one of the second sensing signals with the first bit of the second spreading code; and During the second acquisition cycle in the acquisition period, a second one of the second sensing signals is convolved with the second bit of the second spreading code.

10. The system according to claim 1, wherein the sensing line comprises a first sensing line and a second sensing line, and the acquisition circuit: receiving a first sensing signal at the first sensing line and receiving a second sensing signal at the second sensing line; spreading the first sensed signal in response to a first spreading code of the mutually orthogonal spreading codes; spreading the second sensing signal in response to a second spreading code of the mutually orthogonal spreading codes; as well as The expanded first sensing signal and the expanded second sensing signal are accumulated.

11. The system of claim 1 , wherein the digital controller decodes the accumulated spread-encoded sense signals in response to the mutually orthogonal spreading codes.

12. The system of claim 1, wherein the digital controller determines touch information in response to the channel capacitance measurements.

13. The system of claim 1, wherein the digital controller provides the mutually orthogonal spreading codes.

14. The system according to claim 1, further comprising a digital logic circuit, the digital logic circuit receiving the extended encoded sensing signal and the acquisition period information and providing an extended sensing signal.

15. The system of claim 1, wherein the mutually orthogonal spreading codes include: a first spreading code, the first spreading code comprising a first set of bits; and A second spreading code includes a second set of bits.

16. A method for collecting a sensing signal from a capacitive sensor, comprising: receiving one or more sensing signals at one or more sensor channels associated with a capacitive sensor; spreading encoding the one or more sensed signals, wherein spreading encoding the one or more sensed signals comprises applying spreading codes to the one or more sensed signals in response to mutually orthogonal spreading codes, wherein each bit of the spreading code is one of a logic zero or a logic one; as well as One or more spread encoded sensing signals are accumulated.

17. The method of claim 16, wherein at least one of the mutually orthogonal spreading codes is a code comprising two or more bits.

18. The method of claim 17, comprising receiving the sensing signal during an acquisition period, the acquisition period comprising two or more acquisition cycles.

19. The method according to claim 18, comprising: During an acquisition period, receiving a first sensing signal among the sensing signals at a first sensing line; spreading the first sensing signal in response to a first spreading code during a first acquisition cycle in the acquisition period; as well as The first sensing signal is spread in response to the first spreading code during a second acquisition cycle in the acquisition period.

20. The method according to claim 19, comprising: convolving a first one of the first sensing signals with a first bit of the first spreading code; as well as A second one of the first sensed signals is convolved with a second bit of the first spreading code.

21. The method according to claim 19, comprising: During the acquisition period, receiving a second sensing signal among the sensing signals at a second sensing line; spreading the second sensing signal in response to a second spreading code during the first acquisition cycle in the acquisition period; as well as The second sensing signal is spread in response to the second spreading code during the second acquisition cycle in the acquisition period.

22. The method according to claim 21, comprising: convolving a first one of the second sensing signals with a first bit of the second spreading code; as well as A second one of the second sensing signals is convolved with a second bit of the second spreading code.

23. The method of claim 16, comprising: receiving a first sensing signal at a first sensing line and receiving a second sensing signal at a second sensing line; spreading the first sensed signal in response to a first spreading code of the mutually orthogonal spreading codes; spreading the second sensing signal in response to a second spreading code of the mutually orthogonal spreading codes; as well as The expanded first sensing signal and the expanded second sensing signal are accumulated.

24. The method of claim 23, comprising decoding the accumulated spread coded sensing signals in response to the mutually orthogonal spreading codes.

25. The method of claim 16, further comprising determining at least one channel capacitance measurement in response to the one or more spread encoded sense signals.

26. The method of claim 25, comprising determining touch information in response to the at least one channel capacitance measurement.

27. The method of claim 16, comprising: decoding the accumulated spread-encoded sensed signals in response to the mutually orthogonal spreading codes; integrating one or more individual spread encoded sensed signals; as well as One or more capacitive channel measurements are determined in response to the integrated one or more individual spread encoded sense signals.

28. The method of claim 16, wherein each spreading code is associated with one of the one or more sensor lines.

29. The method of claim 16, wherein spreading the sensed signal in response to the mutually orthogonal spreading codes comprises: spreading the sensed signal in response to a first spreading code comprising a first set of bits; as well as The sense signal is spread in response to a second spreading code including a second set of bits.

30. A controller for capacitive sensing, the controller comprising: A decoder, the decoder: decoding the accumulated sensed signal in response to one or more spreading codes, wherein the one or more spreading codes are mutually orthogonal spreading codes, and wherein each bit of the spreading code in the one or more spreading codes is one of a logic zero or a logic one; as well as integrating the decoded spread-encoded sensing signal; and A processor determines one or more capacitive channel measurements in response to the integrated decoded spread encoded sense signals.

31. The controller of claim 30, wherein the one or more extension codes include: a first spreading code, said first spreading code comprising a first set of bits, and a second spreading code, said second spreading code comprising a second set of bits, The second group of bits is orthogonal to the first group of bits.

32. The controller of claim 30, wherein the decoder: A first decoded spread-encoded sensing signal of the decoded spread-encoded sensing signals is determined in response to a first spreading code of the one or more spreading codes and the accumulated sensing signal.

33. The controller of claim 32, wherein the first decoded extended encoded sensing signal comprises at least two intermediate values, and the decoder integrates the first decoded extended encoded sensing signal by adding the at least two intermediate values.

34. A controller according to claim 33, wherein the decoder: A second decoded spread coded sensing signal among the decoded spread coded sensing signals is determined in response to a second spreading code among the one or more spreading codes and the accumulated sensing signal.

35. The controller of claim 34, wherein the second decoded extended encoded sensing signal comprises at least two intermediate values, and the decoder integrates the second decoded extended encoded sensing signal by adding the at least two intermediate values.

36. The controller of claim 30, wherein the processor determines touch information in response to the one or more capacitive channel measurements.

37. The controller of claim 30, wherein the processor provides the one or more spreading codes to an acquisition circuit.

38. A capacitance sensing system comprising: a sensor circuit comprising sensing lines corresponding to channels of the capacitive sensing system; an encoder that encodes a sensed signal indicative of a capacitance at the sensor circuit, wherein the encoder performs the encoding by: spreading-encoding the first sensing signal in response to the first spreading code; as well as performing spread encoding on the second sensing signal in response to a second spread code, wherein the first spreading code is orthogonal to the second spreading code, and wherein each bit of the spreading code is one of a logical one or a logical zero; an accumulator, the accumulator accumulating the extended encoded sensing signal; a decoder that obtains a spread coded intermediate signal that indicates a contribution of the channel of the capacitive sensing system to the accumulated spread coded sensing signal; and A digital logic component determines a channel capacitance measurement in response to the encoded intermediate signal.

39. The system of claim 38, wherein the decoder obtains a spread coded intermediate signal indicating a contribution of the channel of the capacitive sensing system to the accumulated spread coded sensing signal by: Responsive to a first spreading code, obtaining a first spread coded intermediate signal, the first spread coded intermediate signal indicating a contribution of a first channel of the capacitive sensing system to an accumulated spread coded sense signal; and In response to a second spreading code, a second spread coded intermediate signal is obtained, the second spread coded intermediate signal being indicative of a contribution of a second channel of the capacitive sensing system to the accumulated spread coded sense signal.

40. The system of claim 39, wherein: The first spreading code comprises a first set of bits; and The second spreading code comprises a second set of bits.

41. A capacitance sensing system comprising: An encoder that encodes a driver signal in response to a spreading code, wherein each bit of the spreading code is one of a logical one or a logical zero, and wherein the encoder performs the encoding by: encoding a first driver signal in response to a first spreading code; as well as encoding a second driver signal in response to a second spreading code, wherein the second spreading code is orthogonal to the first spreading code; a sensor circuit that provides a sense signal in response to the extended encoded driver signal; an accumulator, the accumulator accumulating the sensing signal; A decoder that obtains a spread coded intermediate signal that indicates a contribution of a sensing channel of the capacitive sensing system to an accumulated sensing signal accumulated over a plurality of acquisition cycles, wherein the decoder obtains the spread coded intermediate signal that indicates a contribution of the sensing channel of the capacitive sensing system to the accumulated sensing signal by: obtaining a first spread coded intermediate signal in response to the first spreading code, the first spread coded intermediate signal indicating a contribution of a first channel of the capacitive sensing system to the accumulated sensing signal; as well as responsive to a second spreading code, obtaining a second spreading coded intermediate signal, the second spreading coded intermediate signal indicating a contribution of a second channel of the capacitive sensing system to the accumulated sensing signal, and A digital logic component determines a channel capacitance measurement in response to the encoded intermediate signal.

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