Comparator circuit having latching behavior and digital output sensors therefrom

摘要

A digital output sensor includes a sensing structure that outputs a differential sensing signal and includes at least one sensing element. An integrated circuit includes a substrate including signal conditioning circuitry for conditioning the sensing signal that includes a differential amplifier coupled to receive the sensing signal and provide first and second differential outputs and a comparator having input transistors coupled to receive outputs from the differential amplifier. The comparator also includes first and second current-mirror loads that provide differential drive currents and are coupled to the input transistors in a cross coupled configuration to provide hysteresis. An output driver is coupled to receive the differential drive currents. An output stage includes at least one output transistor which is coupled to the output driver for providing a digital output for the sensor. A voltage regulator is coupled to receive a supply voltage and output at least one regulated supply voltage.

主权项

1. A digital output sensor, comprising:
a sensing structure comprising at least one sensing element, said sensing structure outputting a differential sensing signal, and an integrated circuit comprising a substrate including signal conditioning circuitry for conditioning said sensing signal, said signal conditioning circuitry comprising:
a differential amplifier coupled to receive said sensing signal and provide first and second differential outputs;a comparator having input transistors coupled to receive outputs from said differential amplifier, said comparator comprising first and second current-mirror loads coupled to said input transistors in a cross coupled configuration to provide hysteresis, said first and second current-mirror loads providing differential drive currents, wherein said comparator further comprises a first current regulator, said first current regulator comprising a matching resistor that is coupled to said regulated supply voltage and a current mirror coupled to said matching resistor, wherein said current mirror is coupled to provide bias current for said comparator, wherein a voltage across said matching resistor is approximately equal to a voltage across said sensing structure;an output driver coupled to receive said differential drive currents;an output stage comprising at least one output transistor coupled to said output driver for providing a digital output for said sensor, anda voltage regulator coupled to receive a supply voltage and output at least one regulated supply voltage, said regulated supply voltage coupled to said sensing structure, said differential amplifier and said comparator.