Driving electrodes with different phase signals
A controller includes drive circuitry to drive one target drive electrode of a touch sensitive device with a series of predetermined phase pulses and to drive at least one other drive electrode of the touch sensitive device with a corresponding series of out-of-phase pulses. Sense circuitry receives signal transferred to sense electrodes from the drive electrodes of the touch sensitive device. The received signal is responsive to one or more touches on the touch sensitive device.
1. A controller comprising:
drive circuitry operable to:
drive, over a time period, one target drive electrode of a touch sensitive device with a series of pulses having a predetermined phase, the series of pulses having the predetermined phase being a series of consecutive pulses having the predetermined phase; and
drive, over the time period, each of at least first and second drive electrodes of the touch sensitive device with a corresponding series of out-of-phase pulses, the first and second drive electrodes each being directly adjacent to the target drive electrode, one or more of the first and second drive electrodes being driven using fractional bursts of out-of-phase pulses such that at least one of the first and second drive electrodes is not driven with a corresponding out-of-phase pulse for at least one pulse of the series of pulses; and
sense circuitry operable to receive signal transferred to sense electrodes from the drive electrodes of the touch sensitive device, wherein the received signal is responsive to one or more touches on the touch sensitive device.
2. The controller of claim 1 , wherein, in addition to driving each of the at least first and second electrodes of the touch sensitive device with the corresponding series of out-of-phase pulses, the drive circuitry is operable to drive, over the time period, each of all other drive electrodes in the touch sensitive device with a corresponding series of out-of-phase pulses.
3. The controller of claim 1 , wherein the out-of-phase pulses are of opposite polarity to the pulses having the predetermined phase.
4. The controller of claim 1 , wherein a number of out-of-phase pulses in the series of pulses is different than a number of predetermined phase pulses.
5. The controller of claim 1 , and further comprising a touch sensitive device having drive electrodes coupled to the drive circuitry and sense electrodes coupled to the sense circuitry.
6. The controller of claim 5 , wherein the drive and sense electrodes are formed in a single layer.
7. The controller of claim 5 , wherein the drive and sense electrodes are formed in separate layers.
8. The controller of claim 1 , and further comprising signal processing logic to determine a reference signal from the received signals acquired during driving multiple target drive electrodes.
9. The controller of claim 8 , wherein the reference signal is a normalized average of the received signals acquired during driving multiple target drive electrodes.
10. The controller of claim 8 , wherein the reference signal is a minimum of the received signals.
11. The controller of claim 8 , wherein the signal processing logic determines a position signal by subtracting the reference signal from one or more of the received signals.
12. A method comprising:
pulsing, over a time period, a target field emitting electrode of a touch sensitive device with a series of predetermined phase pulses, the series of predetermined phase pulses being a series of consecutive pulses;
pulsing, over the time period, each of at least first and second field emitting electrodes of the touch sensitive device with a corresponding series of out-of-phase pulses, the first and second field emitting electrodes each being directly adjacent to the target field emitting electrode, the first and second field emitting electrodes being pulsed using fractional bursts of out-of-phase pulses such that the first and second field emitting electrodes are not pulsed with a corresponding out-of-phase pulse for at least one pulse of the series of pulses; and
acquiring signal from at least one receive electrode to determine a position of one or more touches on the touch sensitive device.
13. The method of claim 12 , wherein, in addition to pulsing each of the at least first and second field emitting electrodes with the corresponding series of out-of-phase pulses, the method includes pulsing, over the time period, each of all other drive electrodes in the touch sensitive device with a corresponding series of out-of-phase pulses.
14. The method of claim 12 , wherein the out-of-phase pulses are of opposite polarity to the predetermined phase pulses.
15. The method of claim 12 , wherein a number of out-of-phase pulses in the series of pulses is different than a number of predetermined phase pulses.
16. The method of claim 12 , and further comprising determining a reference signal from acquired signals during driving multiple target drive electrodes for a touch.
17. The method of claim 16 , wherein the reference signal is a normalized average of the acquired signals.
18. The method of claim 16 , and further comprising determining a touch position by subtracting the reference signal from one or more of the acquired signals.
19. A system comprising:
drive circuitry operable to sequentially drive, over a time period, target drive electrodes of a touch sensitive device with a series of predetermined phase pulses, the series of predetermined phase pulses being a series of consecutive pulses, and to drive, over the time period, each of at least first and second drive electrodes of the touch sensitive device with a corresponding series of out-of-phase pulses, the first and second drive electrodes being directly adjacent to at least one of the target drive electrodes, one or more of the first and second drive electrodes being driven using fractional bursts of out-of-phase pulses such that at least one of the first and second drive electrodes is not driven with a corresponding out-of-phase pulse for at least one pulse of the series of pulses;
sense circuitry operable to receive signal transferred to multiple sense electrodes from the drive electrodes of the touch sensitive device, wherein the received signal is responsive to a touch on the touch sensitive device; and
signal processing logic operable to determine a reference signal from the received signals acquired during driving multiple target drive electrodes for the touch.