Drive Signals for a Touch Sensor

Abstract

In one embodiment, a method includes generating a drive signal configured to drive a plurality of drive electrodes of a touch sensor. The method also includes modifying the drive signal such that each drive electrode is driven by a drive signal having a unique first characteristic. The method further includes receiving a plurality of sense signals from a plurality of sense electrodes of the touch sensor. The method additionally includes determining a location of a touch input relative to the touch sensor based on at least the first characteristic of the plurality of sense signals.

1 .- 5 . (canceled) 
     
     
         6 . An apparatus comprising:
 a controller comprising a drive circuit operable, when coupled to a plurality of electrodes of a touch sensor, to provide a subset of the plurality of electrodes with a drive signal; and   a demultiplexer circuit operable, when coupled between the subset of the plurality of electrodes and the controller, to divide the drive signal from the drive circuit into a plurality of drive signals.   
     
     
         7 . The apparatus of  claim 6 , wherein each drive signal from among the plurality of drive signals has a different frequency. 
     
     
         8 . The apparatus of  claim 6 , wherein each drive signal from among the plurality of drive signals has a different time slot. 
     
     
         9 . The apparatus of  claim 6 , wherein the controller comprises one drive circuit. 
     
     
         10 . The apparatus of  claim 6 , wherein each electrode of the subset of the plurality of electrodes is coupled to a different output of one demultiplexer circuit. 
     
     
         11 . The apparatus of  claim 6 , wherein the demultiplexer circuit is within the controller. 
     
     
         12 . The apparatus of  claim 6 , wherein the drive circuit is operable to provide one drive signal per sense cycle. 
     
     
         13 . A method, comprising:
 generating a drive signal;   modifying the drive signal to drive a plurality of drive electrodes of a touch sensor, wherein each of the plurality of drive electrodes is driven by a corresponding drive signal having a unique first characteristic;   receiving a plurality of sense signals from a plurality of sense electrodes of the touch sensor; and   determining a location of a touch input relative to the touch sensor based on at least the first characteristic of the plurality of sense signals.   
     
     
         14 . The method of  claim 13 , wherein:
 modifying the drive signal to drive the plurality of drive electrodes of the touch sensor comprises delaying the drive signal for a plurality of different lengths of time, each different length of time corresponding to a different drive electrode of the plurality of drive electrodes, wherein each corresponding drive signal is a portion of the modified drive signal, the portion having been delayed by a corresponding length of time; and   determining the location of a touch input relative to the touch sensor is based on at least a timing characteristic of the sense signals.   
     
     
         15 . The method of  claim 13  wherein:
 modifying the drive signal to drive the plurality of drive electrodes of the touch sensor comprises dividing the drive signal into a plurality of drive signals comprising different frequencies, each different frequency corresponding to a different drive electrode of the plurality of drive electrodes; and 
 determining the location of a touch input relative to the touch sensor is based on at least a frequency characteristic of the sense signals. 
 
     
     
         16 . The method of  claim 13  wherein:
 modifying the drive signal to drive the plurality of drive electrodes of the touch sensor comprises dividing the drive signal into a plurality of drive signals comprising different time slots, each different time slot corresponding to a different drive electrode of the plurality of drive electrodes; and 
 determining the location of a touch input relative to the touch sensor is based on at least a time slot characteristic of the sense signals. 
 
     
     
         17 . The method of  claim 13 , wherein generating the drive signal comprises generating one drive signal. 
     
     
         18 . The method of  claim 13 , wherein generating the drive signal comprises generating the drive signal once per sense cycle. 
     
     
         19 . A non-transitory computer-readable medium comprising logic, the logic operable to, when executed by one or more processors, cause the one or more processors to perform operations comprising:
 generating a drive signal;   modifying the drive signal to drive a plurality of drive electrodes of a touch sensor, wherein each of the plurality of drive electrodes is driven by a corresponding drive signal having a unique first characteristic;   receiving a plurality of sense signals from a plurality of sense electrodes of the touch sensor; and   determining a location of a touch input relative to the touch sensor based on at least a first characteristic of the plurality of sense signals.   
     
     
         20 . The non-transitory computer-readable medium of  claim 19 , wherein:
 modifying the drive signal to drive the plurality of drive electrodes of the touch sensor comprises delaying the drive signal for a plurality of different lengths of time, each different length of time corresponding to a different drive electrode of the plurality of drive electrodes, wherein each corresponding drive signal is a portion of the modified drive signal, the portion having been delayed by a corresponding length of time; and   determining the location of a touch input relative to the touch sensor is based on at least a timing characteristic of the sense signals.   
     
     
         21 . The non-transitory computer-readable medium of  claim 19 , the operations further comprising:
 modifying the drive signal to drive the plurality of drive electrodes of the touch sensor comprises dividing the drive signal into a plurality of drive signals comprising different frequencies, each different frequency corresponding to a different drive electrode of the plurality of drive electrodes; and   determining the location of a touch input relative to the touch sensor is based on at least a frequency characteristic of the sense signals.   
     
     
         22 . The non-transitory computer-readable medium of  claim 19 , wherein:
 modifying the drive signal to drive the plurality of drive electrodes of the touch sensor comprises dividing the drive signal into a plurality of drive signals comprising different time slots, each different time slot corresponding to a different drive electrode of the plurality of drive electrodes; and   determining the location of a touch input relative to the touch sensor is based on at least a time slot characteristic of the sense signals.   
     
     
         23 . The non-transitory computer-readable medium of  claim 19 , wherein generating the drive signal comprises generating one drive signal. 
     
     
         24 . The non-transitory computer-readable medium of  claim 19 , wherein generating the drive signal comprises generating the drive signal once per sense cycle.