Sensing apparatus having switch resistance compensation circuit and associated methods

A method comprising using an apparatus to detect a sensing event at a resistive element in a passive array of an apparatus, the apparatus comprising:

• a row selector switch configured to connect a current source to a row of resistive elements of the passive array;
• a column selector switch configured to connect a column of resistive elements of the passive array to ground, wherein the row selector switch and column selector switch select a resistive element in the passive array;
• and
• a feedback column selector switch configured to connect all columns of resistive elements to a voltage source, except for the column connected to ground by the column selector switch;
• the voltage source configured to apply a voltage to the one or more columns of resistive elements connected to the voltage source, the voltage matching a voltage dropped over the resistive element connected in a circuit formed in part by the row selector switch and column selector switch;
• and further comprising one or more of:
• a row selector switch compensation circuit configured to apply a voltage across a row dummy element equal and opposite to a voltage dropped over the row selector switch;
• a column selector switch compensation circuit configured to apply a voltage across a column dummy element equal and opposite to a voltage dropped over the column selector switch;
• or
• a feedback column selector switch compensation circuit configured to apply a voltage across a feedback column dummy element equal and opposite to a voltage dropped over the feedback column selector switch.

A computer readable medium comprising computer program code stored thereon, the computer readable medium and computer program code being configured to, when run on at least one processor, control the operation of an apparatus, the apparatus comprising:

• a passive array of resistive elements;
• a row selector switch configured to connect a current source to a row of resistive elements of the passive array;
• a column selector switch configured to connect a column of resistive elements of the passive array to ground, wherein the row selector switch and column selector switch select a resistive element in the passive array;
• and
• a feedback column selector switch configured to connect all columns of resistive elements to a voltage source, except for the column connected to ground by the column selector switch;
• the voltage source configured to apply a voltage to the one or more columns of resistive elements connected to the voltage source, the voltage matching a voltage dropped over the resistive element connected in a circuit formed in part by the row selector switch and column selector switch;
• and further comprising one or more of:
• a row selector switch compensation circuit configured to apply a voltage across a row dummy element equal and opposite to a voltage dropped over the row selector switch;
• a column selector switch compensation circuit configured to apply a voltage across a column dummy element equal and opposite to a voltage dropped over the column selector switch;
• or
• a feedback column selector switch compensation circuit configured to apply a voltage across a feedback column dummy element equal and opposite to a voltage dropped over the feedback column selector switch;
• the control providing for:
• detecting a sensing event at a resistive element in the passive array by switching the one or more of the row selector switch compensation circuit, the column selector switch compensation circuit and the feedback column selector switch compensation circuit.