Abstract: A magnetoresistance sensing device includes an on-chip coil capable of generating a magnetic field measured by a wheat stone bridge. The on-chip coil is used in a compensation loop and constructed in parallel with a main signal path using a separate, matched xMR compensation bridge. The separate xMR bridge allows generating and measuring a compensation signal continuously and differentially, which improves signal fidelity without introducing noise into the primary signal path. One or more chopper switches are provided to eliminate offset and flicker noise.

Abstract: Methods and apparatus for a magnetic field sensor IC package having groups of arrays of TMR elements each having a pinning direction. An on-chip coil is routed under the TMR elements to conduct current for generating a magnetic field to stimulate the TMR elements. The device may be configured to sense changes in an applied magnetic field.

Abstract: Methods and apparatus for a magnetic field sensor having a first set of MR elements configured to change in resistance due to an applied magnetic field having an orientation in a sensitive axis of the first set of MR elements and a second set of MR elements that are immune to the applied magnetic field. The second set of MR elements is configured to change in resistance due to temperature. A processor can compensate for the response of the first set of MR elements based on the temperature information from the second set of MR elements.

Abstract: Methods and apparatus for a magnetic field sensor IC package having groups of arrays of TMR elements each having a pinning direction. An on-chip coil is routed under the TMR elements to conduct current for generating a magnetic field to stimulate the TMR elements. The device may be configured to sense changes in an applied magnetic field.

Abstract: Methods and apparatus for a magnetic field sensor having a first set of MR elements configured to change in resistance due to an applied magnetic field having an orientation in a sensitive axis of the first set of MR elements and a second set of MR elements that are immune to the applied magnetic field. The second set of MR elements is configured to change in resistance due to temperature. A processor can compensate for the response of the first set of MR elements based on the temperature information from the second set of MR elements.

Abstract: Methods and apparatus for canceling inductive coupling in a magnetic field sensing device having one or more Hall elements. A device can include a Hall element having a first pair of first and second voltage sensing terminals at diametrically opposed locations on the Hall element, and a second pair of third and fourth voltage sensing terminals diametrically opposed locations on the Hall element. A first mirror conductive path extends around a perimeter of the Hall element in a first direction a second mirror conductive path extends around the perimeter of the Hall element in a second direction so that the first and second mirror conductive paths are on opposite sides of the Hall element and are equal and opposite to cancel inductive coupling.

Abstract: Methods and apparatus for canceling inductive coupling in a magnetic field sensing device having one or more Hall elements. A device can include a Hall element having a first pair of first and second voltage sensing terminals at diametrically opposed locations on the Hall element, and a second pair of third and fourth voltage sensing terminals diametrically opposed locations on the Hall element. A first mirror conductive path extends around a perimeter of the Hall element in a first direction a second mirror conductive path extends around the perimeter of the Hall element in a second direction so that the first and second mirror conductive paths are on opposite sides of the Hall element and are equal and opposite to cancel inductive coupling.

Abstract: In a general aspect, a circuit can include an input circuit configured to receive an input signal, and an amplifier circuit coupled with the input circuit. The amplifier circuit can include an amplifier, and first and second feedback paths. The first feedback path can be from a positive output to a negative input of the amplifier, and the second feedback path can be from a negative output to a positive input of the first amplifier. The circuit can also include a loop circuit configured to provide a local feedback loop for the first amplifier and configured to control current flow into the positive input of the first amplifier and current flow into the negative input of the first amplifier. The circuit can also include a control circuit that is configured to enable the loop circuit in response to a magnitude of the input signal exceeding a threshold.

Abstract: In a general aspect, a circuit can include an input circuit configured to receive an input signal, and an amplifier circuit coupled with the input circuit. The amplifier circuit can include an amplifier, and first and second feedback paths. The first feedback path can be from a positive output to a negative input of the amplifier, and the second feedback path can be from a negative output to a positive input of the first amplifier. The circuit can also include a loop circuit configured to provide a local feedback loop for the first amplifier and configured to control current flow into the positive input of the first amplifier and current flow into the negative input of the first amplifier. The circuit can also include a control circuit that is configured to enable the loop circuit in response to a magnitude of the input signal exceeding a threshold.

Abstract: In one general aspect, an apparatus can include a first terminal, a second terminal, and a resistive element extending between the first terminal and the second terminal. The resistive element can include a first via in contact with a first segment of a first metal layer and a first segment of a second metal layer, and can include a second via in contact with the first segment of the second metal layer and a second segment of the first metal layer. The apparatus can also include a third via in contact with the second segment of the first metal layer and a third segment of the second metal layer.

Abstract: In a general aspect, a circuit can include an amplifier circuit including a first amplifier, a first feedback path, and a second feedback path. The first feedback path can provide a feedback path from a positive output of the first amplifier to a negative input of the first amplifier. The second feedback path can provide a feedback path from a negative output of the first amplifier to a positive input of the first amplifier, The circuit can also include a loop circuit including a second amplifier, The loop circuit can be configured to provide a local feedback loop for the first amplifier and configured to control current flow into the positive input of the first amplifier and into the negative input of the first amplifier.

Abstract: In a general aspect, a circuit can include an amplifier circuit including a first amplifier, a first feedback path, and a second feedback path. The first feedback path can provide a feedback path from a positive output of the first amplifier to a negative input of the first amplifier. The second feedback path can provide a feedback path from a negative output of the first amplifier to a positive input of the first amplifier. The circuit can also include a loop circuit including a second amplifier. The loop circuit can be configured to provide a local feedback loop for the first amplifier and configured to control current flow into the positive input of the first amplifier and into the negative input of the first amplifier.

Abstract: In a general aspect, a system can include a fully differential amplifier circuit that includes a first amplifier, and first and second feedback paths. The first feedback path can provide a feedback path from a positive output of the first amplifier to a negative input of the first amplifier. The second feedback path can provide a feedback path from a negative output of the first amplifier to a positive input of the first amplifier. The system can include a chopper clock circuit configured to output a variable duty cycle chopper clock signal. The system can include a common mode loop circuit including a second amplifier and chopper switches. The common mode loop circuit can be configured as a local feedback loop for the first amplifier. The chopper switches can be configured to receive the chopper clock signal and control current flow into the positive and negative inputs.

Abstract: In a general aspect, an apparatus can include a signal analyzer configured to analyze a signal associated with a processing pipeline, and a dynamic element matching (DEM) selection module configured to select a DEM algorithm from a plurality of DEM algorithms based on the analysis performed by the signal analyzer. The apparatus can include a set of circuit elements where each circuit element from the set of circuit elements has the same logical configuration, and a circuit element selection module configured to select a subset of the set of circuit elements based on the selected DEM algorithm.

Abstract: In one general aspect, an apparatus can include a first terminal, a second terminal, and a resistive element extending between the first terminal and the second terminal. The resistive element can include a first via in contact with a first segment of a first metal layer and a first segment of a second metal layer, and can include a second via in contact with the first segment of the second metal layer and a second segment of the first metal layer. The apparatus can also include a third via in contact with the second segment of the first metal layer and a third segment of the second metal layer.

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: 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: An apparatus comprises at least one transistor configured as analog switch, a well biasing circuit configured to provide a dynamic electrical bias to a bulk region of the at least one transistor, and a comparator circuit in electrical communication with the well biasing circuit and the transistor. The comparator circuit is configured to detect a first operating condition of the transistor and a second operating condition of the transistor. The well biasing circuit is configured to apply a first electrical bias to the bulk region of a transistor when the first operating condition is detected and apply a second electrical bias to the bulk region of the transistor when the second operating condition is detected, and wherein the comparator is configured to apply hysteresis to detection of the first and second operating conditions.

Abstract: In certain examples an integrated circuit protection circuit can include a circuit module, and an isolation device. The isolation device can be configured to couple a ground node of the circuit module to a power ground in an on state, and to isolate the ground node of the circuit module from the power ground in an off state, wherein the isolation module is configured to enter the off state when the IC receives a negative input voltage.

Abstract: This application discusses apparatus and methods for reducing supply voltage induced band gap voltage variation. In an example, a method of compensating a reference voltage current source for supply voltage variation can include providing at least a portion if a reference current for establishing the reference voltage using a first output transistor coupled to the supply voltage, maintaining a constant voltage across the first output transistor using a second output transistor coupled between the first output transistor and an output node, modulating a compensation impedance between a first node and ground as the supply voltage varies, the first node located where the first output transistor is coupled to the second output transistor, and wherein the modulating includes modulating the compensation impedance to substantially equal an output impedance, the output impedance measured between an output node and an input for the supply voltage.