Abstract: A magnetic field sensor includes a magnetic field sensing element to generate a magnetic field signal indicative of a sensed magnetic field, a modulator to modulate the magnetic field signal at a chopping frequency, a front end amplifier coupled to receive the magnetic field signal and generate an amplified signal, and a demodulator configured to demodulate the amplified signal at the chopping frequency. The sensor further includes a low pass filter to process the amplified signal and generate a low pass filtered signal and a Schmitt trigger circuit. The Schmitt trigger circuit includes a comparator having a first input coupled to receive the low pass filtered signal, a second input coupled to receive a reference signal, and an output at which a comparator output signal is provided. The comparator is configured to perform a plurality of comparisons within a chopping time period that is the inverse of the chopping frequency.

Abstract: Apparatus includes an ADC configured to convert an analog signal to a digital signal, a comparator having a first input responsive to the analog signal, a second input responsive to the digital signal, and an output at which a comparison signal is provided, and an output checker configured to process the comparison signal to generate a fault signal indicative of whether a fault has occurred in the ADC. The comparator can be an analog comparator in which case the digital signal is converted to an analog signal for the comparison or a digital comparator in which case an additional ADC is provided to convert the analog signal into a digital signal for the comparison. Embodiments include more than one ADC in which case summation elements are provided to sum the analog signals and the digital signals for the comparison.

Abstract: A two-wire electronic circuit can sense a voltage across terminals of a transistor and control an electrical current of the two-wire electronic circuit in accordance with the sensed voltage.

Abstract: A multichannel magnetic field sensor including a plurality of magnetic field sensing elements includes a multiplexed signal path. A front end amplifier is coupled to receive a first magnetic field signal during a first time interval and a second magnetic field signal during a second time interval. A first low pass filter processes the amplified signal during the first time interval and a second low pass filter processes the amplified signal during the second time interval. A sinc filter is coupled to receive the first low pass filtered signal during the first time interval and the second low pass filtered signal during the second time interval. A Schmitt trigger circuit includes a comparator to process the sinc filter output signal and to generate a first comparator output signal during the first time interval and a second comparator output signal is provided during the second time interval.

Abstract: A method comprising: obtaining at least three sampled values m, each of the sampled values m including a respective first component that is obtained based on a first signal and a respective second component that is obtained based on a second signal and solving a system of equations to yield at least one of (i) an offset adjustment vector k, (ii) a sensitivity mismatch coefficient ?, and (iii) a non-orthogonality coefficient s, the system of equations being arranged to model each of the sampled values m as a function of: a respective one of a plurality of number arrays, a magnetic field, and the at least one of (i) the offset adjustment vector k, (ii) the sensitivity mismatch coefficient ?, and (iii) the non-orthogonality coefficient s.

Abstract: Apparatus includes an ADC configured to convert an analog signal to a digital signal, a comparator having a first input responsive to the analog signal, a second input responsive to the digital signal, and an output at which a comparison signal is provided, and an output checker configured to process the comparison signal to generate a fault signal indicative of whether a fault has occurred in the ADC. The comparator can be an analog comparator in which case the digital signal is converted to an analog signal for the comparison or a digital comparator in which case an additional ADC is provided to convert the analog signal into a digital signal for the comparison. Embodiments include more than one ADC in which case summation elements are provided to sum the analog signals and the digital signals for the comparison.

Abstract: A sensor includes: 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, and 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 is configured to receive the first internal signal and output a first amplified signal; and a second amplifier is configured to receive the second internal signal and output a second amplified signal. A gain adjustment circuit is configured 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.

Abstract: A method for testing a signal path in a sensor, the signal path including a filter circuit and a comparator circuit, the method including: closing a first signal line that is arranged to bypass a first capacitor in the filter circuit; injecting a test signal into the signal path after the first signal line is closed; and detecting whether a signal that is output by the comparator circuit in response to the test signal satisfies a predetermined condition.

Abstract: A sensor includes: 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, and 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 is configured to receive the first internal signal and output a first amplified signal; and a second amplifier is configured to receive the second internal signal and output a second amplified signal. A gain adjustment circuit is configured 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.

Abstract: A method for testing a signal path in a sensor, the signal path including a filter circuit and a comparator circuit, the method including: closing a first signal line that is arranged to bypass a first capacitor in the filter circuit; injecting a test signal into the signal path after the first signal line is closed; and detecting whether a signal that is output by the comparator circuit in response to the test signal satisfies a predetermined condition.

Abstract: A sensor includes an output circuit configured to generate a sensor output signal based on an input signal having a logic high or low level, as may be provided by a Schmitt trigger circuit. During normal operation, the output switches between a first percentage of the supply voltage for logic high and a second percentage of the supply voltage for logic low. To convey a failure at the output, an output signal is output as either ground or the supply voltage when a fault is detected. As such, a fault can be communicated any time the output voltage is not equal to the first percentage or the second percentage of the supply voltage.

Abstract: A sensor includes an output circuit configured to generate a sensor output signal based on an input signal having a logic high or low level, as may be provided by a Schmitt trigger circuit. During normal operation, the output switches between a first percentage of the supply voltage for logic high and a second percentage of the supply voltage for logic low. To convey a failure at the output, an output signal is output as either ground or the supply voltage when a fault is detected. As such, a fault can be communicated any time the output voltage is not equal to the first percentage or the second percentage of the supply voltage.

Abstract: Apparatus and methods provide an output signal indicative of a failure of a filter circuit and/or a Schmitt trigger circuit of a magnetic field sensor. A magnetic field sensor includes one or more magnetic field sensing elements that generate a magnetic field signal, a filter circuit that filters the magnetic field signal, a Schmitt trigger circuit that compares the filtered signal to a Schmitt trigger threshold during a first time period, and a diagnostic circuit coupled to the filter circuit that compares the Schmitt trigger threshold to a diagnostic threshold during a second time period that does not overlap with the first time period. An output signal indicative of a failure is output when the diagnostic threshold is greater than a predetermined percentage or absolute value above or below the Schmitt trigger threshold.

Abstract: A sensor includes an output circuit configured to generate a sensor output signal based on an input signal having a logic high or low level, as may be provided by a Schmitt trigger circuit. During normal operation, the output switches between a first percentage of the supply voltage for logic high and a second percentage of the supply voltage for logic low. To convey a failure at the output, an output signal is output as either ground or the supply voltage when a fault is detected. As such, a fault can be communicated any time the output voltage is not equal to the first percentage or the second percentage of the supply voltage.

Abstract: A sensor includes an output circuit configured to generate a sensor output signal based on an input signal having a logic high or low level, as may be provided by a Schmitt trigger circuit. During normal operation, the output switches between a first percentage of the supply voltage for logic high and a second percentage of the supply voltage for logic low. To convey a failure at the output, an output signal is output as either ground or the supply voltage when a fault is detected. As such, a fault can be communicated any time the output voltage is not equal to the first percentage or the second percentage of the supply voltage.

Abstract: Apparatus and methods provide an output signal indicative of a failure of a filter circuit and/or a Schmitt trigger circuit of a magnetic field sensor. A magnetic field sensor includes one or more magnetic field sensing elements that generate a magnetic field signal, a filter circuit that filters the magnetic field signal, a Schmitt trigger circuit that compares the filtered signal to a Schmitt trigger threshold during a first time period, and a diagnostic circuit coupled to the filter circuit that compares the Schmitt trigger threshold to a diagnostic threshold during a second time period that does not overlap with the first time period. An output signal indicative of a failure is output when the diagnostic threshold is greater than a predetermined percentage or absolute value above or below the Schmitt trigger threshold.