Patent application number | Description | Published |
20110133810 | System and Method for a Semiconductor Switch - In one embodiment, a semiconductor circuit for coupling a first node to a second node includes a first transistor having a first terminal coupled to the first node, a second terminal coupled to the second node, and a control terminal coupled to a control node. The circuit also includes a level shifting circuit having a series diode for coupling a bulk terminal of the first transistor to the control node, and a supply coupling circuit coupled between a first power supply node and the control node. | 06-09-2011 |
20110234528 | SAMPLE AND HOLD CAPACITANCE TO DIGITAL CONVERTER - A circuit for converting charge measured from a touch screen into a digital signal can include a sample and hold circuit. The sample and hold circuit can sample and integrate a charge from a capacitive sense matrix, and hold a voltage signal representing the measured charge. A sigma delta converter can convert the voltage into a digital value. | 09-29-2011 |
20110242048 | CAPACITIVE SENSING ANALOG FRONT END - A capacitive sensing analog front end for a touchscreen system having an improved signal-to-noise ratio includes a capacitance-to-voltage converter having an input for coupling to an external sampling capacitor, a summer having a first input coupled to an output of the capacitance-to-voltage converter, a low pass filter having an input coupled to an output of the summer and an output for providing an output signal; and a sample-and-hold circuit having an input coupled to the output of the low pass filter and an output coupled to a second input of the summer. The signal-to-noise ratio of the touchscreen system is improved by extracting the DC shift of a touch signal during a monitoring period and then subtracting the DC shift before integrating the touch signal. | 10-06-2011 |
20120112817 | METHOD AND APPARATUS FOR CAPACITANCE SENSING - A capacitance-to-digital converter for an extended range of capacitances includes a reference capacitor and one or more offset capacitors. Electrical charge accumulated in the offset capacitors is used to at least partially cancel the charge accumulated in a sensed capacitance to facilitate matching with a charge accumulated in the reference capacitor. The residual charge is passed to an integrator, the output from which is quantized and used to control switching of the capacitors. Immunity to tonal external noises and improved conversion speed are achieved by controlling the capacitor switching with a spread spectrum clock. The capacitance-to-digital converter may be used, for example, for sensing of the capacitances of capacitive elements in touch and proximity displays or other user interfaces. | 05-10-2012 |
20120153991 | COMPARATOR WITH OFFSET COMPENSATION AND IMPROVED DYNAMIC RANGE - A comparator having first and second stages can provide component offset compensation and improved dynamic range. The first stage can receive first and second input signals and produce first and second output signals. The second stage can be coupled to the first stage to receive the first and second output signals at first and second input terminals of the second stage. The second stage can provide a voltage to the first and second terminals that differs from the supply voltage by less than a voltage of a diode drop. The comparator is operable to receive input voltages that reach the supply voltage. | 06-21-2012 |
20130069805 | LOW EMI KEYPAD CIRCUITRY - 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. | 03-21-2013 |
20130169456 | TESTING OF ANALOG-TO-DIGITAL CONVERTERS - Complete testing of an analog-to-digital converter (ADC) can be carried out using digital signals and at high speeds. Circuit elements are added to an ADC so that a first phase of testing may be carried out using a limited number of analog test voltages. The ADC may then be reconfigured using added circuit elements to disable conventional analog-to-digital conversion. A digital signal may then be applied to the ADC to rapidly test all switching elements used in analog-to-digital conversion. According to some implementations, testing times for ADCs may be reduced from hours to milliseconds. | 07-04-2013 |
20140002108 | CAPACITIVE PROXIMITY SENSOR WITH ENABLED TOUCH DETECTION | 01-02-2014 |
20140004905 | DIRECTIONAL CAPACITIVE PROXIMITY SENSOR WITH BOOTSTRAPPING | 01-02-2014 |
20140035861 | TOUCH SCREEN PANEL WITH SLIDE FEATURE - A touch screen having a capacitive touch-sensitive pad overlaying a display area incorporates one or more slide features each having conductive plates. The conductive plates are located outside the display area of the touch screen and are powered via one or more connections to existing touch sensor circuitry comprising the touch-sensitive pad. The slide features of the touch screen do not obstruct a user's view of the display screen and, when compared to conventional touch screen slide features, reduce the circuitry required for detecting and/or processing a slide touch. | 02-06-2014 |
20140077823 | HIGH SIGNAL TO NOISE RATIO CAPACITIVE SENSING ANALOG FRONT-END - Capacitance sensing circuits and methods are provided. The capacitance sensing circuit includes a capacitance-to-voltage converter configured to receive a signal from a capacitance to be sensed and to provide an output signal representative of the capacitance, an output chopper configured to convert the output signal of the capacitance-to-voltage converter to a sensed voltage representative of the capacitance to be sensed, an analog accumulator configured to accumulate sensed voltages during an accumulation period of NA sensing cycles and to provide an accumulated analog value, an amplifier configured to amplify the accumulated analog value, and an analog-to-digital converter configured to convert the amplified accumulated analog value to a digital value representative of the capacitance to be sensed. The analog accumulator may include a low pass filter having a frequency response to filter wideband noise. | 03-20-2014 |
20140078096 | CONFIGURABLE ANALOG FRONT-END FOR MUTUAL CAPACITANCE SENSING AND SELF CAPACITANCE SENSING - Capacitance sensing circuits and methods are provided. A dual mode capacitance sensing circuit includes a capacitance-to-voltage converter having an amplifier and an integration capacitance coupled between an output and an inverting input of the amplifier, and a dual mode switching circuit responsive to mutual mode control signals for a controlling signal supplied from a capacitive touch matrix to the capacitance-to-voltage converter in a mutual capacitance sensing mode and responsive to self mode control signals for controlling signals supplied from the capacitive touch matrix to the capacitance-to-voltage converter in a self capacitance sensing mode, wherein the capacitance sensing circuit is configurable for operation in the mutual capacitance sensing mode or the self capacitance sensing mode. | 03-20-2014 |
20140117950 | VOLTAGE REGULATOR CIRCUIT - A voltage regulator circuit includes a differential amplifier stage. The gate terminal of a first n-channel MOSFET is coupled to an output of the differential amplifier stage. A resistor is coupled between the drain terminal and gate terminal of the first n-channel MOSFET. The drain terminal of the first n-channel MOSFET drives the gate of a second n-channel MOSFET whose drain terminal is at the input of a current mirror circuit. An output of the current mirror circuit forms the regulated voltage output. A feedback circuit is coupled between the regulated voltage output and one input of the voltage regulator circuit. Another input of the voltage regulator circuit is configured to receive a reference voltage. | 05-01-2014 |
20140312919 | CONFIGURABLE ANALOG FRONT-END FOR MUTUAL CAPACITANCE SENSING AND SELF CAPACITANCE SENSING - Capacitance sensing circuits and methods are provided. A dual mode capacitance sensing circuit includes a capacitance-to-voltage converter having an amplifier and an integration capacitance coupled between an output and an inverting input of the amplifier, and a switching circuit responsive to mutual mode control signals for a controlling signal supplied from a capacitive touch matrix to the capacitive to voltage converter in a mutual capacitance sensing mode and responsive to self mode control signals for controlling signals supplied from the capacitive touch matrix to the capacitance-to-voltage converter in a self capacitance sensing mode, wherein the capacitance sensing circuit is configurable for operation in the mutual capacitance sensing mode or the self capacitance sensing mode. | 10-23-2014 |