Abstract: A capacitive sensing structure includes a first sensing electrode located in a first layer for sensing a first capacitance and producing a first sense signal indicative of the sensed first capacitance. A transmit electrode is located in the first layer and positioned surrounding 90%+ of a perimeter of the first sensing electrode. A second sensing electrode is located in the first layer and positioned surrounding 90%+ of a perimeter of the transmit electrode, the second sensing electrode to sense a second capacitance and produce a second sense signal indicative of the sensed second capacitance. Controller circuitry receives the first and second sense signals, compares a change in the sensed first capacitance to a change in the sensed second capacitance, and produces an output signal indicative of a user touch based upon the comparison between the change in the sensed first capacitance and the change in the sensed second capacitance.

Abstract: A capacitive sensing structure includes a first sensing electrode located in a first layer for sensing a first capacitance and producing a first sense signal indicative of the sensed first capacitance. A transmit electrode is located in the first layer and positioned surrounding 90%+ of a perimeter of the first sensing electrode. A second sensing electrode is located in the first layer and positioned surrounding 90%+ of a perimeter of the transmit electrode, the second sensing electrode to sense a second capacitance and produce a second sense signal indicative of the sensed second capacitance. Controller circuitry receives the first and second sense signals, compares a change in the sensed first capacitance to a change in the sensed second capacitance, and produces an output signal indicative of a user touch based upon the comparison between the change in the sensed first capacitance and the change in the sensed second capacitance.

Abstract: Disclosed is a touch sensor and method for detecting a touch in a capacitive touchscreen application, wherein the touch sensor is capable of distinguishing between a finger hovering above the touch sensor and a touch from a stylus having a small contact surface area without having to adjust the sensitivity of the touch sensor. The touch sensor includes a first sensing electrode, a transmit electrode, and a second sensing electrode, wherein the second sensing electrode is positioned substantially around the perimeter of the inner circuitry (i.e., transmit electrode and first sensing electrode). A touch is detected by sensing changes in a first capacitance between the transmit electrode and first sensing electrode and a second capacitance between the transmit electrode and second sensing electrode. The changes in the first and second capacitances are compared to determine whether the changes in the capacitances are due to a finger hover or a touch.

Abstract: Disclosed is a touch sensor and method for detecting a touch in a capacitive touchscreen application, wherein the touch sensor is capable of distinguishing between a finger hovering above the touch sensor and a touch from a stylus having a small contact surface area without having to adjust the sensitivity of the touch sensor. The touch sensor includes a first sensing electrode, a transmit electrode, and a second sensing electrode, wherein the second sensing electrode is positioned substantially around the perimeter of the inner circuitry (i.e., transmit electrode and first sensing electrode). A touch is detected by sensing changes in a first capacitance between the transmit electrode and first sensing electrode and a second capacitance between the transmit electrode and second sensing electrode. The changes in the first and second capacitances are compared to determine whether the changes in the capacitances are due to a finger hover or a touch.

Abstract: Disclosed is keypad circuitry operable to detect a pressed key while reducing electromagnetic interference (EMI). The keypad circuitry is operable to reduce EMI in two ways: a) reducing the voltage swing occurring at the row circuitry and column circuitry of the keypad, and b) reducing the number of signal transitions by restricting the signal transitions to occurring at the column and row corresponding to a pressed key. By limiting signal transitions to occurring only at the row and column corresponding to a pressed key, fewer signal transitions occur, and thus, less EMI is produced. Additionally, reduced voltage swings at the row circuitry and column circuitry results in reduced EMI.

Abstract: Disclosed is keypad circuitry operable to detect a pressed key while reducing electromagnetic interference (EMI). The keypad circuitry is operable to reduce EMI in two ways: a) reducing the voltage swing occurring at the row circuitry and column circuitry of the keypad, and b) reducing the number of signal transitions by restricting the signal transitions to occurring at the column and row corresponding to a pressed key. By limiting signal transitions to occurring only at the row and column corresponding to a pressed key, fewer signal transitions occur, and thus, less EMI is produced. Additionally, reduced voltage swings at the row circuitry and column circuitry results in reduced EMI.

Abstract: An amplifier output stage having an output transistor connected to a high supply voltage and a bootstrap terminal coupled to a control terminal of the output transistor through control circuitry. The output stage includes a capacitor arranged between the bootstrap terminal and the output terminal of the output stage for elevating the voltage at the bootstrap terminal above the high supply voltage, and circuitry for limiting the voltage at the bootstrap terminal to a predetermined threshold. The circuitry for limiting the voltage at the bootstrap terminal directly acts on the control terminal of the output transistor to reduce the conductivity of the output transistor when the voltage at the bootstrap terminal exceeds the predetermined threshold.