Sensor and method of sensing

A touch sensor, comprising:

• a plurality of channels;
• a drive circuit coupled to each of the channels;
• for each of the channels, a charge sensing circuit, each of the charge sensing circuits including a charge measurement capacitor;
• and
• a controller coupled to the drive circuit and the charge sensing circuit, the controller being operable to:
• control the drive circuit to induce charge onto each of the channels during a drive part of a measurement cycle;
• control each of the charge sensing circuits to couple a respective charge measurement capacitor to one of the channels during a charge measurement part of the measurement cycle such that the charge induced onto the channel during the drive part of the measurement cycle is transferred to the respective charge measurement capacitor;
• control a first discharge of each of the charge measurement capacitors in parallel;
• control, after the first discharge, a second discharge of each of the measurement capacitors sequentially;
• and
• determine, based on the second discharge, an amount of charge that was remaining in each of the charge measurement capacitors after the first discharge.

A method, comprising:

• controlling a drive circuit coupled to each of a plurality of channels of a touch sensor to induce charge onto each of the plurality of channels during a drive part of a measurement cycle;
• controlling a charge sensing circuit for each of the plurality of channels to couple a charge measurement capacitor respectively to the each of the plurality of channels during a charge measurement part of the measurement cycle to the effect that the charge induced on the at least one of the plurality of channels during the drive part of the measurement cycle is transferred to at least one respective capacitor of the charge measurement capacitors of the charge sensing circuits;
• controlling a first discharge of each of the charge measurement capacitors in parallel;
• controlling, after the first discharge, a second discharge of each of the measurement capacitors sequentially;
• and
• determining, based on the second discharge, an amount of charge that was remaining in each of the charge measurement capacitors after the first discharge.

A touch sensitive control panel comprising:

• a channel matrix comprising
• a first plurality of drive lines having N drive lines,
• a second plurality of sense lines, having M sense lines,
• wherein the channel matrix includes a number of channels equal to N multiplied by M, each of the channels being arranged to sense the presence of an object, each of the channels being disposed adjacent a respective intersection of one of the N drive lines and one of the M sense lines, each of the channels comprising a drive plate (X) connected to one of the N drive lines and a receiving plate (Y) connected to one of the M sense lines, each of the N drive lines is connected to a respective drive circuit, each of the M sense lines is connected to a respective charge sensing circuit including a charge measurement capacitor, and the channel matrix includes a controller, the controller being operable to:
• control each drive circuit to induce charge onto each drive plate of each of the M sense lines connected to each of the N drive lines during a drive part of a measurement cycle;
• control each charge sensing circuit to couple each charge measurement capacitor respectively to the receiving plate of each of the channels during a charge measurement part of the measurement cycle to the effect that the charge induced on each receiving plate of each channel during the drive part of the measurement cycle is transferred to each respective charge measurement capacitor;
• control a first discharge of each of the charge measurement capacitors in parallel;
• control, after the first discharge, a second discharge of each of the measurement capacitors sequentially;
• and
• determine, based on the second discharge, an amount of charge that was remaining in each of the charge measurement capacitors after the first discharge.

A method, comprising:

• controlling a first discharge of each of a plurality of charge measurement capacitors in parallel, each of the plurality of charge measurement capacitors corresponding to one of a plurality of channels of a touch sensor;
• controlling, after the first discharge, a second discharge of each of the measurement capacitors sequentially;
• and
• determining, based on the second discharge, an amount of charge that was remaining in each of the charge measurement capacitors after the first discharge.

An apparatus, comprising:

• control circuitry operable to:
• control a first discharge of each of a plurality of charge measurement capacitors in parallel, each of the plurality of charge measurement capacitors corresponding to one of a plurality of channels of a touch sensor;
• control, after the first discharge, a second discharge of each of the measurement capacitors sequentially;
• and
• determine, based on the second discharge, an amount of charge that was remaining in each of the charge measurement capacitors after the first discharge.