Abstract: A system for detecting a jack configuration comprising a first plurality of switches configured to couple a first headphone jack position to ground. A second plurality of switches configured to couple a second headphone jack position to ground. A microphone bias circuit for applying a microphone bias signal to the second headphone jack position when the first headphone jack position is coupled to ground, and for applying the microphone bias signal to the first headphone jack position when the second headphone jack position is coupled to ground.

Abstract: Presently many audio chips suffer from pop issues, which is especially serious for single ended audio drivers. An audio pop is a disturbance in the output caused by a sudden transition of chip power, particularly when a chip is powered on or powered off. Furthermore, compensation networks included in the amplifiers on audio chips for stability offer a significant path for transmitting power disturbances to the output. Hence, circuitry is developed to suppress pops in the output stages of an amplifier.

Abstract: The systems and methods described herein allow greater access to a banking platform via a mobile device. The customer can initiate a financial transaction using a mobile device, a bank can inform the customer of the nearest financial transaction terminal to perform that service, and the customer can complete that financial transaction at the financial transaction terminal using the mobile device as a user interface. While conventional systems may use a mobile device to transmit payment information at a point of sale terminal of a brick-and-mortar merchant, the embodiments described herein can allow a customer to conduct a transaction at a financial transaction terminal using the mobile device to initiate a transaction at a location away from a financial transaction terminal, to locate the nearest financial transaction terminal providing the required services, and as a user interface while communicating with the financial transaction terminal.

Abstract: A level shifter comprising a first driver transistor receiving an input signal. A gate-controlled transistor coupled to the first driver transistor. A second driver transistor coupled to the gate controlled transistor. An output coupled to the second driver transistor, wherein the gate-controlled transistor is for receiving a predetermined gate voltage when the output voltage exceeds a predetermined value.

Abstract: A circuit for providing a reference voltage can be widely used in audio applications. However, at startup an abrupt start in the reference signal can cause undesirable audible artifacts. A circuit employing feedback of a reference voltage to control the charging of a capacitor which provides the reference voltage can be used to provide a smooth startup to the reference voltage. The circuit contains a differential pair for steering a fixed current source from one path to another as the reference voltage increases. The steered current can then be mirrored into one ore more current mirrors where the newly mirrored current can be squeezed to zero when the difference between a desired reference voltage and the reference voltage approaches zero. This newly mirrored current can be used to charge a capacitor which is used to provide the reference voltage.

Abstract: A reconfigurable amplifier comprising a first operational amplifier having two inputs and an output. A second operational amplifier having two inputs and an output. A plurality of switches coupled to the two inputs and the output of the first operational amplifier and the two inputs and the output of the second operational amplifier, wherein a first configuration of the plurality of switches causes the first operational amplifier and the second operational amplifier to operate as an inverting differential input amplifier, and wherein a second configuration of the plurality of switches causes the first operational amplifier and the second operational amplifier to operate as a non-inverting differential input instrumentation amplifier.

Abstract: A circuit comprising an inverter coupled to an input and receiving an input signal. A first pull-down transistor coupled to the inverter, pulling down an output when the input signal is low. A second pull-down transistor coupled to the input, pulling down a complementary output when the input signal is high. A first pull-up transistor coupled to the complementary output, pulling up the output when the input signal is high. A second pull-up transistor coupled to the output, pulling up the complementary output when the input signal is low. A first switch receiving a first control signal, coupled to the complementary output. A first strong pull-up transistor coupled to the first switch, assisting the pull up of the output. A second switch coupled to the output, receiving a second control signal. A second strong pull-up transistor coupled to the second switch, assisting the pull up of the complementary output.

Abstract: A battery assisted level shifter comprises a pull up transistor pulling up an output when a received input signal is high, a pull down transistor pulling down the output when the received input signal is low, and a battery element to provide voltage offsets. The battery element can be implemented using one or more pull-up transistors for assisting with pulling up the output. The level shifter can be used in class-D amplifiers, DC-DC power converters and interfaces between circuits having different reference voltages.

Abstract: An integrated audio codec includes a high-pass filter to prevent damage to personal computer speakers and other components. The audio codec may be compliant with HD audio standards and can operate with generic software drivers. Tuning of the high-pass filter is provided through an external pin-out where either an external capacitor or external resistors provide an ability to tune the high-pass filter. In one implementation, a tuning voltage is digitized into a tuning code used by a digital high-pass filter. In addition, multiplexers can be used to insure only the audio path leading to the speakers is filtered.

Abstract: A flying disc is formed entirely of a knotted filament, such as knotted, stitched, or crocheted filament, which may comprise yarn, rope, or the like. A generally flat, generally circular web, defining a plane, is formed by pulling loops of the filament through other loops to form successive interconnected rows of knots using, e.g., crochet stitches. In one embodiment, the knotting proceeds in a helical pattern from a central portion of the circular web to a peripheral portion, with stitches added to an otherwise uniform stitching pattern as necessary to maintain a generally flat shape to the web. The center of the circular web may comprise knotted filament, or may include a void or hole. A circumferential lip connected to the periphery of the circular web and extending out of the plane of the circular web, at least during flight, is formed by dropping stitches from a uniform stitching pattern as necessary to create the desired shape.

Abstract: Direct current (DC) offset in and audio driver can cause a constant drain on power even when there is no sound. Furthermore it can cause an audible pop when the audio driver is enabled. A scaled replica output stage can be employed to perform DC offset cancellation offline during a sampling phase. Once DC offset cancellation is achieved, the audio driver uses a full scale output stage during the operation phase.

Abstract: A circuit for providing a reference voltage can be widely used in audio applications. However, at startup an abrupt start in the reference signal can cause undesirable audible artifacts. A circuit employing feedback of a reference voltage to control the charging of a capacitor which provides the reference voltage can be used to provide a smooth startup to the reference voltage. The circuit contains a differential pair for steering a fixed current source from one path to another as the reference voltage increases. The steered current can then be mirrored into one ore more current mirrors where the newly mirrored current can he squeezed to zero when the difference between a desired reference voltage and the reference voltage approaches zero. This newly mirrored current can he used to charge a capacitor which is used to provide the reference voltage.

Abstract: A driver controller comprising a state machine for controlling transitions between a plurality of states. An output switch for providing a low impedance path to ground during transition periods. An output stage for decoupling output signal from driver amplifier during the transition periods.

Abstract: A circuit comprising an inverter coupled to an input and receiving an input signal. A first pull-down transistor coupled to the inverter, pulling down an output when the input signal is low. A second pull-down transistor coupled to the input, pulling down a complementary output when the input signal is high. A first pull-up transistor coupled to the complementary output, pulling up the output when the input signal is high. A second pull-up transistor coupled to the output, pulling up the complementary output when the input signal is low. A first switch receiving a first control signal, coupled to the complementary output. A first strong pull-up transistor coupled to the first switch, assisting the pull up of the output. A second switch coupled to the output, receiving a second control signal. A second strong pull-up transistor coupled to the second switch, assisting the pull up of the complementary output.

Abstract: An audio processing system that includes an audio filter having one or more elements capable of having state, such as a capacitor, an inductor or a delay. A saturation detector is configured to detect saturation of the audio filter and to generate an output when saturation of the filter is detected, such as a switch control signal. A switch is connected to the audio filter and the saturation detector, wherein the state of one or more of the elements of the audio filter is changed when the saturation detector provides the output to the switch, such as when the switch shorts the element and causes the energy stored in the element to be dissipated.

Abstract: A circuit for providing a reference voltage can be widely used in audio applications. However, at startup an abrupt start in the reference signal can cause undesirable audible artifacts. A circuit employing feedback of a reference voltage to control the charging of a capacitor which provides the reference voltage can be used to provide a smooth startup to the reference voltage. The circuit contains a differential pair for steering a fixed current source from one path to another as the reference voltage increases. The steered current can then be mirrored into one or more current mirrors where the newly mirrored current can be squeezed to zero when the difference between a desired reference voltage and the reference voltage approaches zero. This newly mirrored current can be used to charge a capacitor which is used to provide the reference voltage.

Abstract: Presently many audio chips suffer from pop issues, which is especially serious for single ended audio drivers. An audio pop is a disturbance in the output caused by a sudden transition of chip power, particularly when a chip is powered on or powered off. Furthermore, compensation networks included in the amplifiers on audio chips for stability offer a significant path for transmitting power disturbances to the output. Hence, circuitry is developed to suppress pops in the output stages of an amplifier.

Abstract: A circuit for providing a reference voltage can be widely used in audio applications. However, at startup an abrupt start in the reference signal can cause undesirable audible artifacts. A circuit employing feedback of a reference voltage to control the charging of a capacitor which provides the reference voltage can be used to provide a smooth startup to the reference voltage. The circuit contains a differential pair for steering a fixed current source from one path to another as the reference voltage increases. The steered current can then be mirrored into one or more current mirrors where the newly mirrored current can be squeezed to zero when the difference between a desired reference voltage and the reference voltage approaches zero. This newly mirrored current can be used to charge a capacitor which is used to provide the reference voltage.

Abstract: A grounding switch is described which operates properly even in the presence of negative voltages on a signal line. The grounding switch uses isolated field effect transistors that have their substrates tied to different voltages. The isolated field effect transistor has a gate voltage and substrate voltage which can be pulled down to a negative voltage when the signal line has a negative voltage allowing the switch to remain open even with a negative voltage.

Abstract: High linearity is essential in audio circuitry. As sampling rates for audio applications are needed, high speed and high linearity are needed in analog and mixed signal portions of audio circuitry such as in current mirrors. A current mirror employs two current paths in an output. The first current path is driven by a fast acting transistor through a resistor. The second current path is driven by a differential amplifier coupled to another transistor through another resistor. The second current path is used to maintain linearity by causing the voltage across both transistors to be the same.