Excitation Voltages for Touch Sensors

A method including applying a first excitation voltage to an electrode of a touch sensor which charges a capacitive node associated with the electrode from a first voltage level to a second voltage level that is greater than the first voltage level. A first measurement measures a charge to change from the first voltage level to the second voltage level. A second excitation voltage is applied to the electrode which charges the capacitive node from the second voltage level to a third voltage level that is greater than the second voltage level. The capacitive node is discharged from the third voltage level to a fourth voltage level that is less than the second voltage level. A second measurement measures a charge to change from the third voltage level to the fourth voltage level. A measured charge signal is generated based on the first measurement and the second measurement.