Touch panel excitation using a drive signal having time-varying characteristics

A method comprising:

• powering a drive electrode of a capacitive touch panel with a drive signal having a first signal characteristic during a first time interval to sense a touch at a coordinate location defined by the drive electrode and a sensor electrode arranged across the drive electrode;
• powering the drive electrode of the capacitive touch panel with a drive signal having at least a second signal characteristic different from the first signal characteristic during a second time interval subsequent to the first time interval to sense a touch at the coordinate location, wherein the first time interval and the second time interval occur during a scan of the capacitive touch panel to sense a touch at the coordinate location;
• and
• powering the drive electrode of the capacitive touch panel with a drive signal having a third signal characteristic different from the first signal characteristic and the second signal characteristic during a third time interval subsequent to the second time interval.

A capacitive touch panel control system comprising:

• a driver configured to connect to a drive electrode with a sensor electrode arranged across the drive electrode, the drive electrode and the sensor electrode defining a coordinate location comprising a capacitor formed at a junction between the drive electrode and the sensor electrode for sensing a touch at the coordinate location, the driver configured to power the drive electrode with a drive signal having a first signal characteristic during a first time interval, and at least a second signal characteristic different from the first signal characteristic during a second time interval subsequent to the first time interval, the first time interval and the second time interval occurring during a scan of the capacitive touch panel to sense a touch at the coordinate location;
• and
• a lookup table for determining the first and second signal characteristics of the drive signal;
• wherein
• the driver is configured to power the drive electrode with a drive signal having a third signal characteristic different from the first signal characteristic and the second signal characteristic during a third time interval subsequent to the second time interval.