Abstract: A transient signal protection circuit includes an input node coupled to a signal line configured to carry an output signal from a first circuit to a second circuit, wherein the signal line is subject to experiencing an unwanted reverse signal from the second circuit to the first circuit. The transient signal protection circuit also includes a comparator module configured to output a clamping signal when it is determined that the unwanted reverse signal includes a value that falls outside an acceptable range of the first circuit; and a power switch coupled to the comparator module and configured to couple the input node to a sink node when the comparator module outputs the clamping signal.

Abstract: An example apparatus includes an output jack including a ground pole and a power output pole, a power supply circuit configured to generate a power signal, a coupler circuit operably coupled to the ground pole and the power output pole of the output jack, such that the coupler circuit is configured to couple the power signal with a noise signal on the ground pole to generate a combined output signal on the power output pole.

Abstract: An apparatus includes a reference voltage circuit having a bandgap input and a reference voltage output. The apparatus also includes a digital-to-analog converter (DAC) coupled to the reference voltage output and having a digital signal input. The apparatus includes an amplifier having a first input coupled to an output of the DAC. The first input is coupled to an output of the amplifier via a feedback resistor. The apparatus includes a resistor coupled to the reference voltage output and having a body terminal coupled to the output of the amplifier.

Abstract: An apparatus includes a resistor having an input coupled to an output of an amplifier. The apparatus also includes a feedback circuit coupled to an output of the resistor and to an input of the amplifier. The feedback circuit includes a first component of a voltage divider.

Abstract: An apparatus includes an amplifier having a first input and a second input. A first feedback resistor is coupled to the first input and has a first body terminal coupled to a first bias terminal. A second feedback resistor is coupled to the second input and has a second body terminal coupled to a second bias terminal.

Abstract: An interface unit of a mobile device coupled to an auxiliary device, the interface unit including: a first plurality of switches configured for power delivery to the auxiliary device; at least one isolation unit coupled to the first plurality of switches, the at least one isolation unit configured to isolate the multiple signals and to prevent disruption of data communication between the mobile device and the auxiliary device; and a second plurality of switches configured for the data communication between the mobile device and the auxiliary device, the second plurality of switches configured to bypass the at least one isolation unit.

Abstract: A method and an apparatus for DC-to-DC conversion are provided. The apparatus is a DC-to-DC converter including a first feedback current control circuit coupled to a first voltage output of the DC-to-DC converter. The first feedback current control circuit is configured to generate a first control current based on a voltage difference between a first reference voltage and the first voltage output of the DC-to-DC converter. The apparatus further includes a constant charge comparator coupled to the first feedback current control circuit and configured to compare an integrated error signal to a threshold to generate a comparison result, the integrated error signal comprising an integration of a first error signal over time, the first error signal based on the first control current.

Abstract: An interface unit of a mobile device coupled to an auxiliary device, the interface unit including: a first plurality of switches configured for power delivery to the auxiliary device; at least one isolation unit coupled to the first plurality of switches, the at least one isolation unit configured to isolate the multiple signals and to prevent disruption of data communication between the mobile device and the auxiliary device; and a second plurality of switches configured for the data communication between the mobile device and the auxiliary device, the second plurality of switches configured to bypass the at least one isolation unit.

Abstract: An apparatus includes an amplifier having a first input and a second input. A first feedback resistor is coupled to the first input and has a first body terminal coupled to a first bias terminal. A second feedback resistor is coupled to the second input and has a second body terminal coupled to a second bias terminal.

Abstract: An apparatus includes an input amplifier stage and a switch that has a first terminal at a virtual ground input of the input amplifier stage.

Abstract: Certain aspects of the present disclosure provide methods and apparatus for setting a voltage level for controlling at least one of a first switch or a second switch, such that an on-resistance of the first switch matches an on-resistance of the second switch. One example circuit generally includes a third switch configured to replicate the first switch and a first cascode device connected in cascode with the third switch; a first amplifier configured to drive the first cascode device; a fourth switch configured to replicate the second switch; a second cascode device connected in cascode with the fourth switch; a second amplifier configured to drive the second cascode device; and a third amplifier configured to compare a voltage at a node coupled to the first and second cascode devices with a reference potential and to control the third switch based on the comparison to set the voltage level.

Abstract: An audio amplifier, including: at least a two stage amplifier configured to receive an input signal and output an amplified output signal, the at least a two stage amplifier including at least one stage amplifier and an output stage amplifier; and an auxiliary stage amplifier having an input coupled to an output of the at least one stage amplifier and an input of the output stage amplifier.

Abstract: An apparatus includes a resistor having an input coupled to an output of an amplifier. The apparatus also includes a feedback circuit coupled to an output of the resistor and to an input of the amplifier. The feedback circuit includes a first component of a voltage divider.

Abstract: A method and an apparatus for DC-to-DC conversion are provided. The apparatus is a DC-to-DC converter including a first feedback current control circuit coupled to a first voltage output of the DC-to-DC converter. The first feedback current control circuit is configured to generate a first control current based on a voltage difference between a first reference voltage and the first voltage output of the DC-to-DC converter. The apparatus further includes a constant charge comparator coupled to the first feedback current control circuit and configured to compare an integrated error signal to a threshold to generate a comparison result, the integrated error signal comprising an integration of a first error signal over time, the first error signal based on the first control current.

Abstract: A voltage reference buffer circuit, including: an amplifier having input terminals and output terminals; a plurality of current sources coupled to the input terminals of the amplifier, the plurality of current sources including a plurality of degeneration resistors coupled to a first plurality of voltage supplies; and a degeneration resistor chopping module comprising a first and second plurality of switches coupled to the plurality of degeneration resistors.

Abstract: Methods, systems, and circuits for providing low-noise amplification with input common mode voltage following are disclosed. A circuit includes: an amplifier configured to receive a voltage input having an input common mode voltage and configured to generate a differential voltage output having an output common mode voltage; a feedback circuit in communication with the amplifier, the feedback circuit configured to receive the input common mode voltage and the differential voltage output and to generate a feedback voltage in response to the input common mode voltage and the differential voltage output; and an adjustable current source of the amplifier configured to receive the feedback voltage and to adjust a tail current of the amplifier in response to the feedback voltage.

Abstract: An apparatus includes an input amplifier stage and a switch that has a first terminal at a virtual ground input of the input amplifier stage.

Abstract: The present disclosure amplifier circuits and methods having boosted slew rates. In one embodiment, an amplifier circuit comprises an output stage comprising a first output transistor, the first output transistor comprising a gate, a source, and a drain, wherein the gate receives a signal to be amplified. A bias circuit biases the gate of the first output transistor. A damping circuit is coupled the gate of the first output transistor and is configured to produce a high impedance at low frequencies and a low impedance at high frequencies. The damping circuit includes a current limit circuit to limit current to the gate of the first output transistor when a voltage on the gate of the first output transistor decreases in response to the signal.

Abstract: An apparatus includes a voltage divider circuit and a reference amplifier coupled to the voltage divider circuit. The reference amplifier is configured to provide a feedback voltage to input circuitry of an amplifier.

Abstract: A low voltage multi-stage amplifier is described. The low voltage multi-stage amplifier includes one or more prior stages. The low voltage multi-stage amplifier also includes a supply stage. The low voltage multi-stage amplifier further includes an output stage that operates with a supply voltage as low as a sum of a threshold voltage of a first transistor in the output stage and a saturation voltage of a second transistor of the supply stage. The supply stage supplies the output stage.