Channel sensitivity matching

A sensor comprising:

• a reference magnetic field generator configured to generate a reference magnetic field that is modulated at a first frequency;
• a first magnetic field sensing element that is configured to generate a first internal signal that is modulated at a second frequency,
• a second magnetic field sensing element that is configured to generate a second internal signal that is modulated at the second frequency;
• a first amplifier configured to receive the first internal signal and output a first amplified signal;
• a second amplifier configured to receive the second internal signal and output a second amplified signal;
• a gain adjustment circuit configured to generate a difference signal by subtracting the first amplified signal from the second amplified signal, demodulate the difference signal at the first frequency and the second frequency to produce a gain adjustment signal, and adjust a gain of at least one of the first amplifier and the second amplifier based on the gain adjustment signal;
• a first signal processing circuit that is configured to generate a first output signal based on the first amplified signal;
• and
• a second signal processing circuit that is configured to generate a second output signal based on the second amplified signal,
• wherein the reference magnetic field generator and the gain adjustment circuit are driven by a first clock signal, the first clock signal having a first waveform, and
• wherein the first signal processing circuit and the second signal processing circuit are driven by a second clock signal, the second clock signal having a second waveform that is inverse of the first waveform.

A sensor comprising:

• a reference magnetic field generator configured to generate a reference magnetic field that is modulated at a first frequency;
• a first magnetic field sensing element that is configured to generate a first internal signal that is modulated at a second frequency;
• a second magnetic field sensing element that is configured to generate a second internal signal that is modulated at the second frequency;
• a first amplifier configured to receive the first internal signal and output a first amplified signal;
• a second amplifier configured to receive the second internal signal and output a second amplified signal;
• a gain adjustment circuit configured to:
• generate a difference signal by subtracting the first amplified signal from the second amplified signal, demodulate the difference signal at the first frequency and the second frequency to produce a gain adjustment signal, and adjust a gain of at least one of the first amplifier and the second amplifier based on the gain adjustment signal;
• a first signal processing circuit that is configured to generate a first output signal based on the first amplified signal;
• and
• a second signal processing circuit that is configured to generate a second output signal based on the second amplified signal,
• wherein the gain adjustment circuit is active during each of a plurality of first periods, and
• wherein the first signal processing circuit and the second signal processing circuit are active during each of a plurality of second periods.

A sensor comprising:

• a reference magnetic field generator configured to generate a reference magnetic field that is modulated at a first frequency;
• a first magnetic field sensing element that is configured to generate a first internal signal that is modulated at a second frequency;
• a second magnetic field sensing element that is configured to generate a second internal signal that is modulated at the second frequency;
• a first amplifier configured to receive the first internal signal and output a first amplified signal;
• a second amplifier configured to receive the second internal signal and output a second amplified signal;
• a gain adjustment circuit configured to:
• generate a difference signal by subtracting the first amplified signal from the second amplified signal, demodulate the difference signal at the first frequency and the second frequency to produce a gain adjustment signal, and adjust a gain of at least one of the first amplifier and the second amplifier based on the gain adjustment signal;
• and
• a gain code generator that is configured to receive the gain adjustment signal and generate a gain code based on the gain adjustment signal,
• wherein adjusting the gain of at least one of the first amplifier and the second amplifier based on the gain adjustment signal includes adjusting the gain of at least one of the first amplifier and the second amplifier based on the gain code.
• a window comparator that is configured to obtain a sample of the gain adjustment signal, identify a threshold window that matches the sample, and increment or decrement a first value that is stored in a register by a second value that corresponds to the threshold window;
• and
• a gain code processor that is configured to generate the gain code based on the first value.

A sensor comprising:

• a first amplifier configured to receive a first internal signal and output a first amplified signal, the first internal signal being generated by a first magnetic field sensing element, the first internal signal being generated, at least in part, in response to a reference magnetic field that is modulated at a first frequency, the first internal signal being modulated at a second frequency;
• a second amplifier configured to receive a second internal signal and output a second amplified signal, the second internal signal being generated by a second magnetic field sensing element, the second internal signal being generated, at least in part, in response to the reference magnetic field that is modulated at the first frequency, the second internal signal being modulated at the second frequency;
• and
• a gain adjustment circuit configured to:
• generate a difference signal by subtracting the first amplified signal from the second amplified signal, demodulate the difference signal at the first frequency and the second frequency to produce a gain adjustment signal, and adjust respective gains of the first amplifier and the second amplifier based on the gain adjustment signal,
• wherein the gain adjustment signal includes a differential feedback signal having a first component that is used to adjust the gain of the first amplifier and a second component that is used to adjust the gain of the second amplifier.

A sensor comprising:

• a first amplifier configured to receive a first internal signal and output a first amplified signal, the first internal signal being generated by a first magnetic field sensing element, the first internal signal being generated, at least in part, in response to a reference magnetic field that is modulated at a first frequency, the first internal signal being modulated at a second frequency;
• a second amplifier configured to receive a second internal signal and output a second amplified signal, the second internal signal being generated by a second magnetic field sensing element, the second internal signal being generated, at least in part, in response to the reference magnetic field that is modulated at the first frequency, the second internal signal being modulated at the second frequency;
• a gain adjustment circuit configured to:
• generate a difference signal by subtracting the first amplified signal from the second amplified signal, demodulate the difference signal at the first frequency and the second frequency to produce a gain adjustment signal, and adjust a gain of at least one of the first amplifier and the second amplifier based on the gain adjustment signal;
• a first signal processing circuit that is configured to generate a first output signal based on the first amplified signal;
• and
• a second signal processing circuit that is configured to generate a second output signal based on the second amplified signal,
• wherein the gain adjustment circuit is driven by a first clock signal, the first clock signal having a first waveform, and
• wherein the first signal processing circuit and the second signal processing circuit are driven by a second clock signal, the second clock signal having a second waveform that is inverse of the first waveform.

A sensor comprising:

• a first amplifier configured to receive a first internal signal and output a first amplified signal, the first internal signal being generated by a first magnetic field sensing element, the first internal signal being generated, at least in part, in response to a reference magnetic field that is modulated at a first frequency, the first internal signal being modulated at a second frequency;
• a second amplifier configured to receive a second internal signal and output a second amplified signal, the second internal signal being generated by a second magnetic field sensing element, the second internal signal being generated, at least in part, in response to the reference magnetic field that is modulated at the first frequency, the second internal signal being modulated at the second frequency;
• a gain adjustment circuit configured to:
• generate a difference signal by subtracting the first amplified signal from the second amplified signal, demodulate the difference signal at the first frequency and the second frequency to produce a gain adjustment signal, and adjust a gain of at least one of the first amplifier and the second amplifier based on the gain adjustment signal;
• a first signal processing circuit that is configured to generate a first output signal based on the first amplified signal;
• and
• a second signal processing circuit that is configured to generate a second output signal based on the second amplified signal,
• wherein the gain adjustment circuit is active during each of a plurality of first periods, and
• wherein the first signal processing circuit and the second signal processing circuit are active during each of a plurality of second periods.

A sensor comprising:

• a first amplifier configured to receive a first internal signal and output a first amplified signal, the first internal signal being generated by a first magnetic field sensing element, the first internal signal being generated, at least in part, in response to a reference magnetic field that is modulated at a first frequency, the first internal signal being modulated at a second frequency;
• a second amplifier configured to receive a second internal signal and output a second amplified signal, the second internal signal being generated by a second magnetic field sensing element, the second internal signal being generated, at least in part, in response to the reference magnetic field, the second internal signal being modulated at the second frequency;
• a gain adjustment circuit configured to:
• generate a difference signal by subtracting the first amplified signal from the second amplified signal, demodulate the difference signal at the first frequency and the second frequency to produce a gain adjustment signal;
• and
• a gain code generator that is configured to receive the gain adjustment signal, generate a gain code based on the gain adjustment signal, and adjust a gain of at least one of the first amplifier and the second amplifier,
• wherein the gain code generator includes:
• a window comparator that is configured to obtain a sample of the gain adjustment signal, identify a threshold window that matches the sample, and increment or decrement a first value that is stored in a register by a second value that corresponds to the threshold window, and a gain code processor that is configured to generate the gain code based on the first value.