Abstract: Methods and apparatus for calibrating an audio system including headset coupled to an electronic device via an audio dongle. In an example, a circuit configured to couple a Universal Serial Bus (USB) audio dongle with an audio circuit of an electronic device can include a first impedance configured to couple with a first audio channel of the audio circuit, a second impedance coupled in series with the first impedance and configured to couple with a second audio channel of the audio circuit, a third impedance coupled to a ground sense channel and to a node common to the first impedance and the second impedance, and a controller configured to initiate a first signal on the first channel, to monitor crosstalk of the first signal on the second audio channel and to adjust a setting of the third impedance to reduce the crosstalk.

Abstract: This document discusses, among other things, a detection circuit configured to receive an output of a window comparator over a range of input values and to measure a difference between first and second thresholds of the window comparator, and a trim circuit configured to adjust at least one of the first or second thresholds using the measured difference between the first and second thresholds.

Abstract: An apparatus comprises an integrated circuit (IC) comprising an external IC connection, an IC substrate connection, a voltage clamp circuit and an under voltage circuit. The voltage of the IC substrate connection is set to a first voltage when a voltage of the external connection of the IC is within a normal operating voltage range. The voltage clamp circuit is configured to clamp the voltage supply of one or more circuits internal to the IC to within a normal operating voltage range when the voltage of the external IC connection exceeds the normal operating voltage range. The under voltage circuit is communicatively coupled to the clamp circuit and configured to set the voltage of the substrate to a second voltage when the voltage at the external IC connection of the IC is less than zero volts.

Abstract: Methods and apparatus for calibrating an audio system including headset coupled to an electronic device via an audio dongle. In an example, a circuit configured to couple a Universal Serial Bus (USB) audio dongle with an audio circuit of an electronic device can include a first impedance configured to couple with a first audio channel of the audio circuit, a second impedance coupled in series with the first impedance and configured to couple with a second audio channel of the audio circuit, a third impedance coupled to a ground sense channel and to a node common to the first impedance and the second impedance, and a controller configured to initiate a first signal on the first channel, to monitor crosstalk of the first signal on the second audio channel and to adjust a setting of the third impedance to reduce the crosstalk.

Abstract: The present subject matter refers to apparatus and methods for identifying a resistance level of a resistor. In an example, circuit configured to identify a resistor can include a plurality of current sources, each current source selectively coupled to the resistor to generate a resistor voltage, a comparator configured to compare the resistor voltage and a reference voltage, and to provide an output indicative of the comparison, and a controller configured to selectively couple a first one or more current sources of the plurality of current sources to the resistor, and to selectively couple a second one or more current sources of the plurality of current sources to the resistor in response to the output indicative of the comparison.

Abstract: This application discusses among other things, apparatus and method for transmitting data with an analog signal without significantly distorting the analog signal. In an example, an apparatus can include an audio channel, a capacitor coupled to a first conductor of the audio channel, the capacitor configured to couple an analog representation of a digital data signal with an analog audio signal on the audio channel, and a frequency modulator configured to receive the digital data signal and to modulate a frequency of an output signal of the frequency modulator based on a logic level of the digital data signal, wherein the analog representation of the digital data signal includes the frequency of the output signal of the frequency modulator.

Abstract: This application discusses methods and apparatus for a data-on-supply repeater. In an example, a repeater can include a repeater circuit configured to receive a power signal at an input and to provide a representation of a received analog data signal at an output, a direction detector configured to receive the power signal from a first bus conductor of a plurality of bus conductors, to identify the first buss conductor of the plurality of bus conductors as a transmitting conductor, and to provide an output indicative of the transmitting conductor, a first input multiplexer configured to couple the transmitting conductor to the input of the repeater circuit in response to the output of the direction detector, and an output multiplexer configured to couple the output of the repeater circuit to a second bus conductor of the plurality of bus conductors, wherein the second bus conductor is different than the transmitting conductor.

Abstract: This document discusses, among other things, apparatus and methods for a detection circuit. In an example, the detection circuit can include a voltage divider configured to receive a first supply voltage from an external device coupled to the detection circuit, first and second transistors configured to receive a control voltage from the voltage divider and to couple an output to ground when the control voltage exceeds a first threshold, and a bias circuit configured to bias the first transistor to set the first threshold.

Abstract: A detection circuit can be configured to receive a digital value from an identification register and to determine a resistance at a conducting terminal of an audio or video jack plug using the digital value. The detection circuit can include a current source that outputs a current according to the digital value from the identification register and a comparator that compares a reference voltage to a voltage created by the current source across the resistance at the conducting terminal of the audio or video jack plug. A control logic circuit can be configured to store the digital value in the identification register, generate an interrupt signal to cause a processor to read the digital value, and identify a function of an accessory device including the audio or video jack plug, when the detection circuit determines the resistance at the conducting terminal of the audio or video jack plug.

Abstract: This document discusses, among other things, systems and methods to provide an internal supply rail with over voltage protection using a host power source, an external power source, and a switch configured to receive indications of host and external power source validity. In an example, the switch can be configured to provide the internal supply rail using the host power source when the indication of host power source validity indicates a valid host power source and the external power source when the indication of host power source validity indicates an invalid host power source and the indication of external power source validity indicates a valid external power source.

Abstract: This application discusses methods and apparatus for a data-on-supply repeater. In an example, a repeater can include a repeater circuit configured to receive a power signal at an input and to provide a representation of a received analog data signal at an output, a direction detector configured to receive the power signal from a first bus conductor of a plurality of bus conductors, to identify the first buss conductor of the plurality of bus conductors as a transmitting conductor, and to provide an output indicative of the transmitting conductor, a first input multiplexer configured to couple the transmitting conductor to the input of the repeater circuit in response to the output of the direction detector, and an output multiplexer configured to couple the output of the repeater circuit to a second bus conductor of the plurality of bus conductors, wherein the second bus conductor is different than the transmitting conductor.

Abstract: This document discusses, among other things, systems and methods to provide an internal supply rail with over voltage protection using a host power source, an external power source, and a switch configured to receive indications of host and external power source validity. In an example, the switch can be configured to provide the internal supply rail using the host power source when the indication of host power source validity indicates a valid host power source and the external power source when the indication of host power source validity indicates an invalid host power source and the indication of external power source validity indicates a valid external power source.

Abstract: This document discusses, among other things, a detection circuit configured to receive an output of a window comparator over a range of input values and to measure a difference between first and second thresholds of the window comparator, and a trim circuit configured to adjust at least one of the first or second thresholds using the measured difference between the first and second thresholds.

Abstract: This application discusses among other things, apparatus and method for transmitting data with an analog signal without significantly distorting the analog signal. In an example, an apparatus can include an audio channel, a capacitor coupled to a first conductor of the audio channel, the capacitor configured to couple an analog representation of a digital data signal with an analog audio signal on the audio channel, and a frequency modulator configured to receive the digital data signal and to modulate a frequency of an output signal of the frequency modulator based on a logic level of the digital data signal, wherein the analog representation of the digital data signal includes the frequency of the output signal of the frequency modulator.

Abstract: A fuel gauge can include a resistor configured to generate predetermined temperature information and a switch configured to couple a temperature sensor to a temperature output of the fuel gauge in a first state and to couple the resistor to the temperature output of the fuel gauge in a second state.

Abstract: A detection circuit can be configured to receive a digital value from an identification register and to determine a resistance at a conducting terminal of an audio or video jack plug using the digital value. The detection circuit can include a current source that outputs a current according to the digital value from the identification register and a comparator that compares a reference voltage to a voltage created by the current source across the resistance at the conducting terminal of the audio or video jack plug. A control logic circuit can be configured to store the digital value in the identification register, generate an interrupt signal to cause a processor to read the digital value, and identify a function of an accessory device including the audio or video jack plug, when the detection circuit determines the resistance at the conducting terminal of the audio or video jack plug.

Abstract: Method and apparatus to provide lambda correction of a current foldback circuit using a regulator including a current foldback circuit are disclosed herein.

Abstract: This document discusses, among other things, apparatus and methods configured to accurately identify accessories coupled to mobile electronic devices over a wide range of temperature, In an example, an apparatus can include a reference voltage generator configured to provide a reference voltage, a comparator configured to compare the reference voltage to a voltage across an accessory-resistor, a current supply configured to be coupled to the accessory resistor and to provide the voltage to the comparator using the accessory resistor. The current supply can include a first sense resistor having a first temperature dependency and a second sense resistor having a second temperature dependency. In an example, the second temperature dependency can be configured to compensate for at least a portion of the first temperature dependency. In an example, at least one of the first or second temperature dependencies can be configured to control a temperature dependency of the apparatus.

Abstract: A detection circuit can be configured to receive a digital value from an identification register and to determine a resistance at a conducting terminal of an audio or video jack plug using the digital value. The detection circuit can include a current source that outputs a current according to the digital value from the identification register and a comparator that compares a reference voltage to a voltage created by the current source across the resistance at the conducting terminal of the audio or video jack plug. A control logic circuit can be configured to store the digital value in the identification register, generate an interrupt signal to cause a processor to read the digital value, and identify a function of an accessory device including the audio or video jack plug, when the detection circuit determines the resistance at the conducting terminal of the audio or video jack plug.

Abstract: This document discusses, among other things, systems and methods to provide an internal supply rail with over voltage protection using a host power source, an external power source, and a switch configured to receive indications of host and external power source validity. In an example, the switch can be configured to provide the internal supply rail using the host power source when the indication of host power source validity indicates a valid host power source and the external power source when the indication of host power source validity indicates an invalid host power source and the indication of external power source validity indicates a valid external power source.