# US 9,437,169 B2 · Touch panel control circuit and semiconductor integrated circuit using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,169 B2 - Document ID: US9437169B2 - Status: Granted - Kind: B2 - Application number: 14/567,386 - Filed: 2014-12-11 - Published: 2015-06-18 - Granted: 2016-09-06 - Earliest claimed: 2013-12-18 - Assignees: Synpatics Japan GK - Applicants: Synaptics Display Devices GK - Inventors: Takayuki Noto; Akihito Akai - Web page: https://patentgrep.com/patent/US9437169B2 ## CPC - G06F 3/0446: {using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes} - G06F 3/04166: {Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving (Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184)} - G09G 5/18: Timing circuits for raster scan displays (specially adapted for television H04N {; synchronisation between the display unit and other display units, videodisc player G09G5/12}) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A touch panel control circuit includes a drive circuit that drives Y electrodes of a touch panel, and a detection circuit that is connected to X electrodes and detects a capacitance value of an intersection capacitor. The drive circuit applies a plurality of pulses to the Y electrodes in a predetermined period. The detection circuit includes a switched capacitor circuit capable of operating with respect to an input signal from the X electrodes in synchronization with the plurality of pulses, and an integration circuit that is connected to an output of the switched capacitor circuit and operates in synchronization with the pulses. The switched capacitor circuit is allowed to operate as a filter, and the switched capacitor circuit is set to have characteristics which have a maximum gain at a direct current and a frequency of a corresponding pulse and in which the gain is suppressed at a frequency therebetween. ## Claims ### Claim 1 A touch panel control circuit configured to connect to a touch panel comprising a first plurality of electrodes arranged in a first direction and a second plurality of electrodes arranged in a second direction, wherein the first plurality of electrodes intersect the second plurality of electrodes to form a plurality of intersection capacitors, the touch panel control circuit comprising: a plurality of drive circuits configured to drive the first plurality of electrodes; and a plurality of detection circuits coupled to the second plurality of electrodes, each detection circuit of the plurality of detection circuits including a corresponding switched capacitor circuit and a corresponding integration circuit coupled to an output node of the corresponding switched capacitor circuit, wherein the detection circuits of the plurality of detection circuits are configured to detect a plurality of capacitance values of the plurality of intersection capacitors, wherein the drive circuits of the plurality of drive circuits are configured to apply a first number of pulses, the first number being at least two, to the first plurality of electrodes within a predetermined period, wherein each switched capacitor circuit is configured to receive an input signal from the second plurality of electrodes and to operate with a sampling frequency which is same or multiple times higher than a frequency of the pulses and in synchronization with the pulses, and wherein each integration circuit is configured to operate in synchronization with the pulses. ### Claim 2 (depends on 1) The touch panel control circuit of claim 1, wherein: each switched capacitor circuit includes a first switched capacitor sub-circuit configured to receive the input signal, and a second switched capacitor sub-circuit configured to receive a first output signal of the first switched capacitor sub-circuit and configured to output a second output signal to the corresponding integration circuit, the first switched capacitor sub-circuit is configured to operate as a finite impulse response (FIR) filter configured to sample the first number of times in the predetermined period and having an order of a second number that is one or more less than the first number, and the second switched capacitor sub-circuit is configured to operate as a switched capacitor filter that samples a third number of times in the predetermined period, the third number being equal to the first number divided by the second number. ### Claim 3 (depends on 2) The touch panel control circuit according to claim 2, wherein: the switched capacitor filter of the second switched capacitor sub-circuit is an infinite impulse response (IIR) filter. ### Claim 4 (depends on 1) The touch panel control circuit according to claim 1, wherein: the switched capacitor circuit includes a first switched capacitor sub-circuit to which the input signal is input, and a second switched capacitor sub-circuit to which a first output signal of the first switched capacitor circuit is input and which outputs a second output signal to the corresponding integration circuit, the first switched capacitor sub-circuit is configured to operate as a QV conversion circuit that converts an amount of electric charge that is input the first number of times in the predetermined period to a voltage and outputs the voltage, and the second switched capacitor sub-circuit is configured to operate as an IIR filter that samples the first number of times in the predetermined period. ### Claim 5 (depends on 1) The touch panel control circuit according to claim 1, wherein: the switched capacitor circuit includes a first switched capacitor sub-circuit to which the input signal is input, and a second switched capacitor sub-circuit to which a first output signal of the first switched capacitor sub-circuit is input and which outputs a second output signal to the corresponding integration circuit, the first switched capacitor sub-circuit is configured to operate in one configuration of a first set of configurations that includes: an FIR filter having an order that is a second number less than the first number, the second number being one or more, the FIR filter configured to sample the first number of times in the predetermined period; a QV conversion circuit configured to convert an amount of electric charge that is input the first number of times in the predetermined period from the input signal to a voltage and to output the voltage; and a switched capacitor integration circuit configured to integrate an amount of electric charge that is input the first number of times in the predetermined period from the input signal and to output a corresponding voltage, the second switched capacitor sub-circuit is configured to operate in one configuration of a second set of configurations that includes: an IIR filter that samples a third number of times in the predetermined period, the third number being the first number divided by the second number; and an IIR filter configured to sample the first number of times in the predetermined period, and the touch panel control circuit is configured to select a configuration of the first set of configurations for operation of the first switched capacitor sub-circuit and to select a configuration of the second set of configurations for operation of the second switched capacitor sub-circuit. ### Claim 6 (depends on 1) The touch panel control circuit according to claim 1, wherein: the switched capacitor circuit includes a first switched capacitor sub-circuit to which the input signal is input, and a second switched capacitor sub-circuit to which a first output signal of the first switched capacitor sub-circuit is input and that outputs a second output signal to the corresponding integration circuit, the first switched capacitor sub-circuit is configured to operate as the integration circuit corresponding to the switched capacitor circuit, the integration circuit being configured to integrate a first set of electric charge input from within the input signal that is input in response to one edge of each of the first number of pulses in the predetermined period and an amount of electric charge input from the input signal that is input in response to another edge of each of the first number of pulses, and the touch panel control circuit is configured to output a third output signal of the first switched capacitor sub-circuit from the detection circuits by stopping operation of the second switched capacitor sub-circuit and the corresponding integration circuit. ### Claim 7 (depends on 1) The touch panel control circuit according to claim 1, wherein: the switched capacitor circuit includes a first switched capacitor sub-circuit to which the input signal is input, and a second switched capacitor sub-circuit to which a first output signal of the first switched capacitor sub-circuit is input and that outputs a second output signal to the corresponding integration circuit, the first switched capacitor sub-circuit is configured to operate as an FIR filter having an order of a second number less than the first number, the second number being an even number, the FIR filter being configured to integrate an amount of electric charge input from within the input signal that is input in response to one edge of each of the first number of pulses in the predetermined period and an amount of electric charge input from within the input signal that is input in response to another edge of the first number of pulses, and the second switched capacitor sub-circuit is configured to operate as a switched capacitor filter that samples a third number of times in the predetermined period, wherein the third number is equal to two times the first number divided by the second number. ### Claim 8 (depends on 7) The touch panel control circuit according to claim 7, wherein: the switched capacitor filter of the second switched capacitor sub-circuit comprises an IIR filter. ### Claim 9 (depends on 1) The touch panel control circuit according to claim 1, wherein: the switched capacitor circuit includes a first switched capacitor sub-circuit to which the input signal is input, and a second switched capacitor sub-circuit to which a first output signal of the first switched capacitor sub-circuit is input and which outputs a second output signal to the corresponding integration circuit, the first switched capacitor sub-circuit is configured to operate as a QV conversion circuit that converts an amount of electric charge input from within the input signal that is input in response to one edge of each of the first number of pulses in the predetermined period and an amount of electric charges input from within the input signal that is input in response to another edge to voltages in which one polarity is inverted and becomes equal to the other polarity, and which outputs the voltages, and the second switched capacitor sub-circuit is configured to operate as an IIR filter that samples a second number of times in the predetermined period, where the second number is two times the first number. ### Claim 10 (depends on 1) The touch panel control circuit according to claim 1, wherein: the switched capacitor circuit includes a first switched capacitor sub-circuit to which the input signal is input, and a second switched capacitor sub-circuit to which a first output signal of the first switched capacitor sub-circuit is input, which outputs a second output signal to the corresponding integration circuit, and is configured to operate in at least two operation modes of a first operation mode, a second operation mode, a third operation mode, a fourth operation mode, a fifth operation mode, and a sixth operation mode, in the first operation mode, the first switched capacitor sub-circuit is configured to operate as an integration circuit that integrates an amount of electric charge that are input a first number of times in the predetermined period from the input signal that which outputs a corresponding voltage, operations of the second switched capacitor sub-circuit and the corresponding integration circuit are stopped, and a third output of the first switched capacitor sub-circuit is output from a corresponding detection circuit of the plurality of detection circuits, in the second operation mode, the first switched capacitor sub-circuit is configured to operate as an FIR filter having an order that is a second number less than the first number, the second number being an even number, the FIR filter configured to sample the first number of times in the predetermined period, and the second switched capacitor sub-circuit is configured to operate as an IIR filter that samples a third number of times in the predetermined period, the third number being the first number divided by the second number, in the third operation mode, the first switched capacitor sub-circuit is configured to operate as a QV conversion circuit that converts an amount of electric charge that is input a first number of times in the predetermined period from the input signal to a voltage and outputs the voltage, and the second switched capacitor circuit is configured to operate as an IIR filter that samples the first number of times in the predetermined period, in the fourth operation mode, the first switched capacitor sub-circuit is configured to operate as an switched capacitor integration circuit that integrates an amount of electric charge input from within the input signal that is input in response to one edge of each of the first number of pulses in the predetermined period and an amount of electric charge input from within the input signal that is input in response to another edge of the first number of pulses, the operations of the second switched capacitor sub-circuit and the integration circuit are stopped, and an output of the first switched capacitor sub-circuit is output from the detection circuit, in the fifth operation mode, the first switched capacitor sub-circuit is allowed to operate as an FIR filter having an order of a second number smaller than the first number, the second number being an even number, the FIR filter integrating an amount of electric charge input from the input signal that is input in response to one edge of each of the first number of pulses in the predetermined period and an amount of electric charge input from the input signal that is input in response to another edge, and the second switched capacitor sub-circuit is configured to operate as a switched capacitor filter that samples a third number of times in the predetermined period, the third number being two times a first number divided by a second number, and in the sixth operation mode, the first switched capacitor sub-circuit is configured to operate as a QV conversion circuit that converts an amount of electric charge input from the input signal that is input in response to one edge of each of the first number of pulses in the predetermined period and an amount of electric charge input from the input signal that is input in response to the other edge to voltages in which one polarity is inverted and becomes equal to the other polarity, and which outputs the voltages, and the second switched capacitor sub-circuit is configured to operate as an IIR filter that samples a fourth number of times in the predetermined period, the fourth number being two times the first number. ### Claim 11 (depends on 1) The touch panel control circuit according to claim 1, wherein: the plurality of drive circuits and the plurality of detection circuits are included on a single semiconductor substrate. ### Claim 12 (depends on 11) The touch panel control circuit according to claim 11, further comprising: a display drive circuit included on the single semiconductor substrate, the display drive circuit configured to be coupled to a display panel that is configured to overlap the touch panel. ### Claim 13 (depends on 12) The touch panel control circuit according to claim 12, further comprising: a microcontroller included on the single semiconductor substrate, the microcontroller configured to control the touch panel control circuit and to read out data based on output of the detection circuit. ### Claim 14 A touch panel control circuit configured to connect to a touch panel comprising a first plurality of electrodes arranged in a first direction and a second plurality of electrodes arranged in a second direction, wherein the first plurality of electrodes intersect the second plurality of electrodes to form a plurality of intersection capacitors, the touch panel control circuit comprising: a plurality of drive circuits configured to drive the first plurality of electrodes by applying a first number of pulses to the first plurality of electrodes in a predetermined period; a plurality of detection circuits coupled to the second plurality of electrodes, each detection circuit of the plurality of detection circuits configured to detect a capacitance value of a corresponding intersection capacitor of the plurality of intersection capacitors; and a sequence control circuit, wherein each detection circuit includes a first switched capacitor circuit that is coupled to each input terminal capable of being connected to the first plurality of electrodes, a first sample-and-hold circuit, a second switched capacitor circuit, a second sample-and-hold circuit, an integration circuit, and a third sample-and-hold circuit that retains an output of the detection circuit that are coupled in series, wherein the first switched capacitor circuit includes a first operational amplifier in which a first positive side input is fixed to a first predetermined potential, a first integration capacitor that is coupled between a first negative side input and a first output of the first operational amplifier, a first switch that is coupled between the first negative side input and the first output of the first operational amplifier, and a second switch that is coupled between the input terminal and the first negative side input of the first operational amplifier, wherein the second switched capacitor circuit includes a second operational amplifier in which a second positive side input is fixed to a second predetermined potential, a second integration capacitor that is coupled between a second negative side input and a second output of the second operational amplifier, and has a configuration in which a part or the entirety of a capacitance value is capable of being discharged by control, and a fourth switch that is coupled between an output of the first sample-and-hold circuit and the second negative side input of the second operational amplifier, wherein the integration circuit includes a third operational amplifier in which a third positive side input is fixed to a predetermined potential, a third integration capacitor that is coupled between a third negative side input and a third output of the third operational amplifier, a third switch that is coupled between the third negative side input and the third output of the third operational amplifier, and a fifth switch that is coupled between an output of the second sample-and-hold circuit and the third negative side input of the third operational amplifier, and wherein the sequence control circuit is configured to control a timing of turning on or off the first switch, the second switch, the third switch, the fourth switch, and the fifth switch of the detection circuit and a timing of discharging a part or the entirety of the second integration capacitor in synchronization with a timing of outputting the pulses with respect to the drive circuit. ### Claim 15 (depends on 14) The touch panel control circuit according to claim 14, wherein: the first switched capacitor circuit is configured to perform control of inverting a connection direction of the first integration capacitor, and the sequence control circuit is configured to control the timing of turning on or off the first switch, the second switch, the third switch, the fourth switch, and the fifth switch of the detection circuit, the timing of discharging a part or the entirety of the second integration capacitor, and a timing of inverting the connection direction of the first integration capacitor in synchronization with a rising edge and a falling edge of the pulses that are output to the drive circuit. ### Claim 16 (depends on 14) The touch panel control circuit according to claim 14, further comprising: an analog-to-digital conversion circuit; and a selection circuit that selects one voltage from a plurality of voltages retained in the third sample-and-hold circuit and supplies the selected voltage to the analog-to-digital conversion circuit, wherein the sequence control circuit is configured to control the plurality of drive circuits in order for the pulses to be sequentially applied to the first plurality of electrodes in a predetermined period to allow the plurality of detection circuits to operate in parallel for every predetermined period, and to control the selection circuit in order for outputs of the plurality of detection circuits to be sequentially supplied to the analog-to-digital conversion circuit. ### Claim 17 (depends on 14) The touch panel control circuit according to claim 14, wherein: the plurality of drive circuits, the plurality of detection circuits, and the sequence control circuit are included on a single semiconductor substrate. ### Claim 18 (depends on 17) The touch panel control circuit according to claim 17, further comprising: a display drive circuit included on the single semiconductor substrate, wherein the display drive circuit is configured to be coupled to a display panel that is configured to overlap the touch panel. ### Claim 19 (depends on 18) The touch panel control circuit according to claim 18, further comprising: a microcontroller included on the single semiconductor substrate, wherein the microcontroller is configured to control the touch panel control circuit and to read out data based on output of the detection circuit.