Abstract: Adaptive reconfiguration of a capacitive touch controller is implemented by estimating the interference spectrum of the signal received by the touch controller. The spectrum of the received signal is used to determine a desired frequency, and the touch panel transmitter is configured to use that desired frequency. The spectrum of the received signal is also used to determine an desired filter transfer function. A filter in the touch panel received signal path is configured to use that desired filter transfer function. The adaptive reconfiguration is focused on improving the signal to noise ratio of the received signal without the need for shielding the touch panel, performing additional scans of the touch panel, or using components that operate at higher power levels.

Abstract: An apparatus that is configurable to perform a forward scan, a row scan, and a column scan is disclosed. The apparatus includes a path selection module coupled to a transmitter and a receiver. The path selection module includes a row-transmit switch, a column-receive switch, a row-receive switch, and a column-transmit switch that are configurable to form various transmit paths and receive paths to perform the forward scan, a row scan, and a column scan. The row-transmit switch and the column-transmit switch cascades switching transistors to protect against large voltage swings present in an output of the transmitter, controls the gate voltage that is applied to these switching transistors to protect against the large voltage swings, and includes additional protection circuitry to ensure their reliability.

Abstract: A method for a touch panel control circuit includes stimulating a touch panel and receiving signals responsive to the stimulating. Based on the received signals, water or another contaminant may be determined to be present on the touch panel. While the contaminant is present on the touch panel, a wet baseline mode of operation in which a different baseline value is used to detect a touch condition for the touch panel. When the contaminant is removed, operation returns to a dry baseline mode.

Abstract: A mode-configurable amplifier comprises a single-ended input for receiving a received signal from a capacitive touch panel, a differential output operable to carry a differential processed signal to a subsequent processing stage, and processing circuitry in communication with the single ended input and the differential output. The processing circuitry comprises mode selection inputs and mode selection circuitry in communication with the mode selection inputs. The mode selection circuitry is operable to configure the processing circuitry into a current operating mode selected from a high-pass filter mode, bandpass filter mode, and a trans-capacitive gain mode. The high-pass filter mode is operable to high-pass filter the received signal to obtain the differential processed signal. The bandpass filter mode is operable to bandpass filter the received signal to obtain the differential processed signal. The wideband gain mode is operable to amplify the received signal to obtain the differential processed signal.

Abstract: A method for touch detection in a touch panel display includes entering a low power touch detection mode and intermittently stimulating the touch panel display with signals to determine if any touch event occurs without locating the touch event on the touch panel. If a touch event is detected, a full scan mode is entered to locate the touch event on the touch panel. This provides both faster touch detection and lower power operation for the touch panel display and controller circuit.

Abstract: Adaptive reconfiguration of a capacitive touch controller is implemented by estimating the interference spectrum of the signal received by the touch controller. The spectrum of the received signal is used to determine a desired frequency, and the touch panel transmitter is configured to use that desired frequency. The spectrum of the received signal is also used to determine an desired filter transfer function. A filter in the touch panel received signal path is configured to use that desired filter transfer function. The adaptive reconfiguration is focused on improving the signal to noise ratio of the received signal without the need for shielding the touch panel, performing additional scans of the touch panel, or using components that operate at higher power levels.

Abstract: A method for a touch panel control circuit includes stimulating a touch panel and receiving signals responsive to the stimulating. Based on the received signals, water or another contaminant may be determined to be present on the touch panel. While the contaminant is present on the touch panel, a wet baseline mode of operation in which a different baseline value is used to detect a touch condition for the touch panel. When the contaminant is removed, operation returns to a dry baseline mode.

Abstract: A mode-configurable amplifier comprises a single-ended input for receiving a received signal from a capacitive touch panel, a differential output operable to carry a differential processed signal to a subsequent processing stage, and processing circuitry in communication with the single ended input and the differential output. The processing circuitry comprises mode selection inputs and mode selection circuitry in communication with the mode selection inputs. The mode selection circuitry is operable to configure the processing circuitry into a current operating mode selected from a high-pass filter mode, bandpass filter mode, and a trans-capacitive gain mode. The high-pass filter mode is operable to high-pass filter the received signal to obtain the differential processed signal. The bandpass filter mode is operable to bandpass filter the received signal to obtain the differential processed signal. The wideband gain mode is operable to amplify the received signal to obtain the differential processed signal.

Abstract: An apparatus that is configurable to perform a forward scan, a row scan, and a column scan is disclosed. The apparatus includes a path selection module coupled to a transmitter and a receiver. The path selection module includes a row-transmit switch, a column-receive switch, a row-receive switch, and a column-transmit switch that are configurable to form various transmit paths and receive paths to perform the forward scan, a row scan, and a column scan. The row-transmit switch and the column-transmit switch cascades switching transistors to protect against large voltage swings present in an output of the transmitter, controls the gate voltage that is applied to these switching transistors to protect against the large voltage swings, and includes additional protection circuitry to ensure their reliability.