Directional capacitive proximity sensor with bootstrapping

A directional capacitive proximity sensing circuit comprising:

• one or more guard electrodes;
• first capacitive sensor circuitry operable to sense a first capacitance and produce a first capacitive sensor reading indicative of the sensed first capacitance, wherein the first capacitive sensor circuitry includes a first capacitive sensor coupled to a first section of at least one of the one or more guard electrodes;
• and
• second capacitive sensor circuitry operable to sense a second capacitance and produce a second capacitive sensor reading indicative of the sensed second capacitance, wherein the second capacitive sensor circuitry includes a second capacitive sensor coupled to a second section of at least one of the one or more guard electrodes,
• wherein the one or more guard electrodes are controlled with a low impedance output to one or more voltages.

A directional capacitive proximity sensing circuit comprising:

• one or more guard electrodes;
• first capacitive sensor circuitry operable to sense a first capacitance and produce a first capacitive sensor reading indicative of the sensed first capacitance, wherein the first capacitive sensor circuitry includes a first capacitive sensor coupled to a first section of at least one of the one or more guard electrodes;
• and
• second capacitive sensor circuitry operable to sense a second capacitance and produce a second capacitive sensor reading indicative of the sensed second capacitance, wherein the second capacitive sensor circuitry includes a second capacitive sensor coupled to a second section of at least one of the one or more guard electrodes,
• wherein the one or more guard electrodes comprises a first guard electrode having the first capacitive sensor coupled to a first section of the first guard electrode, and a second guard electrode having the second capacitive sensor coupled to a second section of the second guard electrode, and
• wherein the first guard electrode is disposed in a device at a first location near a first component of the device, and the second guard electrode is disposed in the device at a second location adjacent the first location and near a second component of the device.

A directional capacitive proximity sensing circuit comprising:

• one or more guard electrodes;
• first capacitive sensor circuitry operable to sense a first capacitance and produce a first capacitive sensor reading indicative of the sensed first capacitance, wherein the first capacitive sensor circuitry includes a first capacitive sensor coupled to a first section of at least one of the one or more guard electrodes;
• and
• second capacitive sensor circuitry operable to sense a second capacitance and produce a second capacitive sensor reading indicative of the sensed second capacitance, wherein the second capacitive sensor circuitry includes a second capacitive sensor coupled to a second section of at least one of the one or more guard electrodes,
• wherein the first section of the at least one of the one or more guard electrodes is disposed near a first component of a device and the second section of the at least one of the one or more guard electrodes is disposed adjacent the first section of the at least one of the one or more guard electrodes and near a second component of the device.

A directional capacitive proximity sensing circuit for use with a mobile device, comprising:

• a guard electrode;
• a first sensor coupled to a first section of the guard electrode;
• a second sensor coupled to a second section of the guard electrode adjacent the first section of the guard electrode;
• first capacitive sensor circuitry coupled to the first sensor, the first capacitive sensor circuitry operable to sense user proximity to the mobile device with respect to the first sensor and to produce a first capacitive sensor reading responsive to the sensed user proximity with respect to the first sensor and indicative of the user proximate to the first sensor;
• second capacitive sensor circuitry coupled to the second sensor, the second capacitive sensor circuitry operable to sense user proximity to the mobile device with respect to the second sensor and to produce a second capacitive sensor reading responsive to the sensed user proximity with respect to the second sensor and indicative of the user proximate to the second sensor;
• and
• output circuitry operable to receive and compare the first and second capacitive sensor readings and produce an output signal to indicate detection of the user proximate to the mobile device in a location nearer the first sensor than the second sensor when the first capacitive sensor reading is different than the second capacitive sensor reading.

An integrated circuit operable to detect a general direction of user proximity with respect to the integrated circuit, the integrated circuit comprising:

• a first switched capacitive integrator circuit including a first sensor plate, the first switched capacitive integrator circuit operable to sense a first capacitance and produce a first output signal in response to the sensed first capacitance;
• a second switched capacitive integrator circuit including a second sensor plate located adjacent the first sensor plate, the second switched capacitive integrator circuit operable to sense a second capacitance and produce a second output signal in response to the sensed second capacitance;
• one or more capacitive plates, wherein at least one of the one or more capacitive plates has a first section coupled to the first sensor plate, and at least one of the one or more capacitive plates has a second section coupled to the second sensor plate;
• and
• output circuitry operable to receive the first output signal and second output signal, and to produce a third output signal operable to indicate detection of the user proximity with respect to at least one of the first sensor plate or the second sensor plate.