Sensor system including multiple comparators

A system including a sensor circuit and comparison circuitry. The sensor circuit is configured to provide a sensed signal. The comparison circuitry is configured to receive an input signal that corresponds to the sensed signal. The comparison circuitry provides output signals that switch state at different levels of the input signal.

BACKGROUND

Sensors, referred to as contactless sensors, can be used to detect the position of a sensed object without contacting the sensed object. Contactless sensors include magnetic sensors, inductive sensors, and capacitive sensors.

Magnetic sensors include Hall-effect sensors and magneto-resistive (XMR) sensors. Where, magnetic sensors are used in sensors, such as position sensors, speed sensors, motion sensors, and proximity sensors in automotive, industrial and consumer applications.

Usually, in Hall-effect sensors, current flows through a Hall-effect sensing element or plate and a magnetic field perpendicular to the current flow deflects charge carriers due to the Lorentz force. The deflected charge carriers create a Hall voltage perpendicular to both the magnetic field and the current flow. This Hall voltage can be measured and is directly proportional to the magnetic field.

Often, position sensors are two state switches, where the position sensor switches from one state to another state based on the distance that the sensed object is from the sensor. If the sensed object is closer to the sensor, the position sensor is in one state and if the sensed object is further away from the sensor, the position sensor is in another state. The position sensor, detects that the sensed object is in one of two regions. However, multiple position sensors are needed to detect that the sensed object is in one of more than two regions. This leads to an increase in the number of sensors and wiring, which increases system costs.

SUMMARY

One embodiment described in the disclosure provides a system including a sensor circuit and comparison circuitry. The sensor circuit is configured to provide a sensed signal. The comparison circuitry is configured to receive an input signal that corresponds to the sensed signal. The comparison circuitry provides output signals that switch state at different levels of the input signal.

DETAILED DESCRIPTION

FIG. 1is a diagram illustrating one embodiment of a sensor system20that senses the position of an object (not shown) and indicates the position of the object in one of four regions. In one embodiment, sensor system20is a magnetic field position sensor. In one embodiment, sensor system20is a radio frequency (RF) position sensor. In one embodiment, sensor system20is part of a gear shift assembly. In other embodiments, sensor system20senses and indicates the position of an object in one region of n number of regions.

Sensor system20includes a sensor circuit22, an amplifier24, three comparators26a-26c, a logic circuit28and two output transistors30aand30b. Sensor circuit22is electrically coupled to the inputs of amplifier24via sensed signal paths32aand32band the output of amplifier24is electrically coupled to each of the comparators26a-26bvia input signal path34.

Sensor circuit22senses the object and provides sensed signals to amplifier24via sensed signal paths32aand32b. Amplifier24receives the sensed signals at32aand32band provides an amplified input signal to comparators26a-26cvia input path34, where the amplified input signal at34corresponds to the sensed signals at32aand32b. In one embodiment, sensor circuit22is a magnetic sensor circuit. In one embodiment, sensor circuit22is an inductive sensor circuit. In one embodiment, sensor circuit22is a capacitive sensor circuit. In one embodiment, sensor circuit22is a Hall-effect sensor circuit. In one embodiment, sensor circuit22is a magneto-resistive (XMR) sensor circuit.

Each of the three comparators26a-26creceives the input signal at34and compares the input signal at34to different threshold values. Also, each of the three comparators26a-26cprovides an output signal to logic circuit28. First comparator26ais electrically coupled to logic circuit28via first output path36a, second comparator26bis electrically coupled to logic circuit28via second output path36b, and third comparator26cis electrically coupled to logic circuit28via third output path36c. In other embodiments, sensor system20includes n comparators that provide n output signals to logic circuit28.

First comparator26areceives the input signal at34and compares the input signal at34to first threshold values. If the input signal at34is above the first threshold values, first comparator26aprovides a first output signal at36ain one state, such as a low state. If the input signal at34is below the first threshold values, first comparator26aprovides the first output signal at36ain another state, such as a high state.

Second comparator26breceives the input signal at34and compares the input signal at34to second threshold values. If the input signal at34is above the second threshold values, second comparator26bprovides a second output signal at36bin one state, such as a low state. If the input signal at34is below the second threshold values, second comparator26bprovides the second output signal at36bin another state, such as a high state.

Third comparator26creceives the input signal at34and compares the input signal at34to third threshold values. If the input signal at34is above the third threshold values, third comparator26cprovides a third output signal at36cin one state, such as a low state. If the input signal at34is below the second threshold values, third comparator26cprovides the third output signal at36cin another state, such as a high state.

Comparators, such as comparators26a-26c, are part of comparison circuitry27. In other embodiments, comparison circuitry27does not include comparators, such as comparators26a-26c, and comparisons of the input signal to the different threshold values are done via different comparison circuitry27, such as in a software solution where the input signal is sampled via an analog-to-digital (AD) converter (not shown) and comparisons are made via software calculations in a controller (not shown).

Logic circuit28receives the first, second, and third output signals at36a-36cand provides logical output signals that indicate which one of the four regions the sensed object is in. Logic circuit28is electrically coupled to the input of first output transistor30avia logic output path38aand to the input of second output transistor30bvia logic output path38b. First output transistor30ahas a first output at40aand is electrically coupled to a reference, such as ground, at42. Second output transistor30bhas a second output at40band is electrically coupled to a reference, such as ground, at44. In other embodiments, logic circuit28provides other signals that indicate which region the sensed object is in, signals such as pulse width modulated (PWM) signals, local interconnect network (LIN) signals, and/or controller area network (CAN) signals.

Logic circuit28receives the three output signals at36a-36cand provides two logical output signals at38aand38bthat indicate which one of four regions the object is in. The first logical output signal at38acontrols first output transistor30aand the second logical output signal at38bcontrols second output transistor30bto output first and second output signals at40aand40b, respectively. In other embodiments, logic circuit28receives n comparator output signals from n comparators and logic circuit28provides logical output signals to indicate which one of n+1 regions the object is in.

In operation, the sensed object is in one of four regions, where the first region is furthest away from sensor system20, the second region is closer to sensor system20than the first region but further away from sensor system20than the third region, the third region is closer to sensor system20than the second region but further away from sensor system20than the fourth region, and the fourth region is closest to sensor system20.

If the sensed object is in the first region, the input signal at34that corresponds to the sensed signals at32aand32b, is below the first, second, and third threshold values and all three comparators26a-26coutput a high state. If the sensed object is in the second region, the input signal at34is above the first threshold values and below the second and third threshold values, such that first comparator26aoutputs a low state and second and third comparators26band26coutput high states. If the sensed object is in the third region, the input signal at34is above the first and second threshold values and below the third threshold values, such that first and second comparators26aand26boutput low states and third comparator26coutputs a high state. If the sensed object is in the fourth region, the input signal at34is above the first, second, and third threshold values and each of the three comparators26a-26coutputs a low state.

Logic circuit28receives the comparator output signals at36a-36cand outputs two logical output signals at38aand38b, which control output transistors30aand30bto provide output signals at40aand40b. If the sensed object is in the first region, all three comparators26a-26coutput a high state and logic circuit28controls output transistors30aand30bto output high states in the output signals at40aand40b. If the sensed object is in the second region, such that first comparator26aoutputs a low state and second and third comparators26band26coutput high states. Logic circuit28receives the one low state and two high states and controls output transistor30ato output a high state and output transistor30bto output a low state. If the sensed object is in the third region, such that first and second comparators26aand26boutput low states and third comparator26coutputs a high state. Logic circuit28receives the two low states and the one high state and controls output transistor30ato output a low state and output transistor30bto output a high state. If the sensed object is in the fourth region, such that each of the comparators26a-26coutputs a low state. Logic circuit28receives the three low states and controls output transistors30aand30bto output low states.

In other embodiments, sensor system20has n number of comparators, where each comparator has different threshold values. The input signal at34is compared via the n comparators to produce n comparator output signals. Logic circuit28receives the n comparator output signals and indicates which region of up to n+1 regions the sensed object is in.

Sensor system20senses the sensed object in one of more than two regions. Using sensor system20reduces the number of sensors and wiring, which reduces system costs.

FIG. 2is a diagram illustrating the operation of sensor system20, where sensor circuit22is a Hall-effect magnetic field sensor. The high and low states at100of comparators26a-26care graphed versus the strength of the magnetic field B at102. As the sensed object gets closer to sensor system20, the magnetic field gets stronger. In region I at104, the magnetic field is weak and the object is furthest away from sensor system20. As the object moves closer to sensor system20, it passes through region II at106, region III at108, and into region IV at110.

In region I at104, the input signal at34that corresponds to the sensed signals at32aand32b, is below the first, second, and third threshold values and each of the three comparators26a-26coutputs a high state. As the object moves closer to sensor system20, comparator26aswitches from a high state to a low state at112, which is operating point one (BOP1). In region II at106, the input signal at34is above the first threshold values and below the second and third threshold values, such that first comparator26aoutputs a low state and second and third comparators26band26coutput high states. As the object moves closer to sensor system20, comparator26bswitches from a high state to a low state at114, which is operating point two (BOP2). In region III at108, the input signal at34is above the first and second threshold values and below the third threshold values, such that first and second comparators26aand26boutput low states and third comparator26coutputs a high state. As the object moves closer to sensor system20, comparator26cswitches from a high state to a low state at116, which is operating point three (BOP3). In region IV at110, the input signal at34is above the first, second, and third threshold values and each of the three comparators26a-26coutputs a low state.

As the sensed object moves further away from sensor system20, the magnetic field gets weaker. The object moves from region IV at110, to region III at108, to region II at106, to region I at104. Each of the three comparators26a-26cis a hysteresis comparator that switches from a low state to a high state at a release point that is different than the operating point for that comparator. This stabilizes sensor system20, such that oscillations between regions due to electrical noise or mechanical vibrations are reduced.

In region IV at110, the input signal at34is above the first, second, and third threshold values and each of the three comparators26a-26coutputs a low state. As the object moves further away from sensor system20, comparator26cswitches from a low state to a high state at118, which is release point three (BRP3). In region III at108, the input signal at34is above the first and second threshold values and below the third threshold values, such that first and second comparators26aand26boutput low states and third comparator26coutputs a high state. As the object moves further away from sensor system20, comparator26bswitches from a low state to a high state at120, which is release point two (BRP2). In region II at106, the input signal at34is above the first threshold values and below the second and third threshold values, such that first comparator26aoutputs a low state and second and third comparators26band26coutput high states. As the object moves further away from sensor system20, comparator26aswitches from a low state to a high state at122, which is release point one (BRP1). In region I at104, the input signal at34that corresponds to the sensed signals at32aand32b, is below the first, second, and third threshold values and each of the three comparators26a-26coutputs a high state.

FIG. 3is a table illustrating the states of comparators26a-26cand output signals40a-40bat130versus region at132. Comparator26ais referred to as Comp1at130a, comparator26bis referred to as Comp2at130b, and comparator26cis referred to as Comp3at130c. Also, output signal40ais referred to as Out1at130dand output signal40bis referred to as Out2at130e.

In region I at132a, each of the comparators26a-26coutputs a high state and logic circuit28controls output transistors30aand30bto output high states in the output signals at40aand40b. In region II at132b, first comparator26aoutputs a low state and second and third comparators26band26coutput high states, and logic circuit28controls output transistor30ato output a high state and output transistor30bto output a low state. In region III at132c, first and second comparators26aand26boutput low states and third comparator26coutputs a high state. Logic circuit28receives the two low states and the one high state and controls output transistor30ato output a low state and output transistor30bto output a high state. In region IV at132d, each of the comparators26a-26coutputs a low state and logic circuit28controls output transistors30aand30bto output low states.

FIG. 4is a diagram illustrating one embodiment of a sensor system200that senses whether the strength of a magnetic field, such as the magnetic field from an object, is in the middle region of three regions. In one embodiment, sensor system200is part of a position sensor that senses the position of the object. In one embodiment, sensor system200is part of a security system. In other embodiments, sensor system200senses and indicates whether the strength of the magnetic field is in one region of n regions.

Sensor system200includes a sensor circuit202, an amplifier204, two comparators206aand206b, a logic circuit208, and an output transistor210. Sensor circuit202is electrically coupled to the inputs of amplifier204via sensed signal paths212aand212b, and the output of amplifier204is electrically coupled to each of the comparators206aand206bvia input signal path214.

Sensor circuit202senses the magnetic field and provides sensed signals to amplifier204via sensed signal paths212aand212b. Amplifier204receives the sensed signals at212aand212band provides an amplified input signal to comparators206aand206bvia input path214, where the amplified input signal at214corresponds to the sensed signals at212aand212b. In one embodiment, sensor circuit202is a magnetic sensor circuit. In one embodiment, sensor circuit202is an inductive sensor circuit. In one embodiment, sensor circuit202is a capacitive sensor circuit. In one embodiment, sensor circuit202is a Hall-effect sensor circuit. In one embodiment, sensor circuit202is an XMR sensor circuit.

Each of the comparators206aand206breceives the input signal at214and compares the input signal at214to different threshold values. Also, each of the comparators206aand206bprovides an output signal to logic circuit208. First comparator206ais electrically coupled to logic circuit208via first output path216aand second comparator206bis electrically coupled to logic circuit208via second output path216b. In other embodiments, sensor system200includes n comparators that provide n output signals to logic circuit208.

First comparator206areceives the input signal at214and compares the input signal at214to first threshold values. If the input signal at214is above the first threshold values, first comparator206aprovides a first output signal at216ain one state, such as a low state. If the input signal at214is below the first threshold values, first comparator206aprovides the first output signal at216ain another state, such as a high state.

Second comparator206breceives the input signal at214and compares the input signal at214to second threshold values. If the input signal at214is above the second threshold values, second comparator206bprovides a second output signal at216bin one state, such as a low state. If the input signal at214is below the second threshold values, second comparator206bprovides the second output signal at216bin another state, such as a high state.

Logic circuit208receives the first and second output signals at216aand216band provides a logical output signal that indicates whether the strength of the magnetic filed is in the middle region of three regions. Logic circuit208is electrically coupled to the input of output transistor210via logic output path218. Output transistor210has an output at220and is electrically coupled to a reference, such as ground, at222. In other embodiments, logic circuit208provides other signals that indicate which region the sensed object is in, signals such as pulse width modulated (PWM) signals, local interconnect network (LIN) signals, and/or controller area network (CAN) signals.

Logic circuit208receives the output signals at216aand216band provides a logical output signal at218that indicates whether the strength of the magnetic field is in the middle region of three regions. The logical output signal at218controls output transistor210to output an output signal at220. In other embodiments, logic circuit208receives n comparator output signals from n comparators and logic circuit208provides logical output signals to indicate which one of n+1 regions the strength of the magnetic field is in.

In operation, the sensed strength of the magnetic field is in one of three regions. The magnetic field strength is weakest in the first region, stronger in the second region than in the first region but weaker in the second region than in the third region, and strongest in the third region.

In the first region, the input signal at214that corresponds to the sensed signals at212aand212bis below the first and second threshold values and both comparators206aand206boutput a high state. In the second region, the input signal at214is above the first threshold values and below the second threshold values, such that first comparator206aoutputs a low state and second comparator206boutputs a high state. In the third region, the input signal at214is above the first and second threshold values, such that first and second comparators206aand206boutput low states.

Logic circuit208receives the comparator output signals at216aand216band outputs a logical output signal at218, which controls output transistor210to provide an output signal at220. In the first region, each of the comparators206aand206boutputs a high state and logic circuit208controls output transistors210to output a low state in the output signal at220. In the second region, first comparator206aoutputs a low state and second comparator206boutputs a high state. Logic circuit208receives the low state and the high state and controls output transistor210to output a high state in the output signal at220. In the third region, first and second comparators206aand206boutput low states and logic circuit208controls output transistor210to output a low state in the output signal at220.

In other embodiments, sensor system200has n number of comparators, where each comparator has different threshold values. The input signal at214is compared via the n comparators to produce n comparator output signals. Logic circuit208receives the n comparator output signals and indicates which region of up to n+1 regions the strength of the magnetic field is in.

Sensor system200indicates whether the strength of the magnetic field is in the second region via a high state in the output signal at220. If the strength of the magnetic field is lower and in the first region or higher and in the third region, sensor system200outputs a low state in the output signal at220.

In one embodiment, sensor system200is used in a security system, where sensor system200detects the position of an object, such as a door/window sensor magnet. If the strength of the magnetic field is in the second region, the door/window is closed and if the strength of the magnetic field is in the first region, the door/window is open. Also, if someone tries to over-ride the door/window sensor via an external magnet, the strength of the magnetic field may be pushed into the third region, where sensor system200outputs a low state in the output signal at220, which alerts the security system to a potential break-in at the door/window.

FIG. 5is a diagram illustrating the operation of sensor system200, where sensor circuit202is a Hall-effect magnetic field sensor. The high and low states at230of comparators206aand206bare graphed versus the strength of the magnetic field B at232. In region I at234, the magnetic field is weakest. In region II at236, the magnetic field is stronger than in region I, but weaker than in region III at238where the magnetic field is strongest.

In region I at234, the input signal at214that corresponds to the sensed signals at212aand212b, is below the first and second threshold values and each of the comparators206aand206boutputs a high state. As the magnetic field strength increases, such as by moving an object closer to sensor system200, comparator206aswitches from a high state to a low state at240, which is operating point one (BOP1). In region II at236, the input signal at214is above the first threshold values and below the second threshold values, such that first comparator206aoutputs a low state and second comparator206boutputs a high state. As the magnetic field strength increases, such as by moving an object closer to sensor system200, comparator206bswitches from a high state to a low state at242, which is operating point two (BOP2). In region III at238, the input signal at214is above the first and second threshold values and each of the comparators206aand206boutputs a low state.

As the magnetic field decreases, such as by moving an object away from sensor system200, the strength of the magnetic field moves from region III at238, to region II at236, to region I at234. Each of the comparators206aand206bis a hysteresis comparator that switches from a low state to a high state at a release point that is different than the operating point for that comparator. This stabilizes sensor system200, such that oscillations between regions due to electrical noise or mechanical vibrations are reduced.

In region III at238, the input signal at214is above the first and second threshold values and each of the comparators206aand206boutputs a low state. As the magnetic field decreases, comparator206bswitches from a low state to a high state at244, which is release point two (BRP2). In region II at236, the input signal at214is above the first threshold values and below the second threshold values, such that first comparator206aoutputs a low state and second comparator206boutputs a high state. As the magnetic field decreases, comparator206aswitches from a low state to a high state at246, which is release point one (BRP1). In region I at234, the input signal at214is below the first and second threshold values and each of the comparators206aand206boutputs a high state.

FIG. 6is a table illustrating the states of comparators206aand206band output signal220at250versus region at252. Comparator206ais referred to as Comp1at250a, comparator206bis referred to as Comp2at250b, and output signal220is referred to as Out at250c.

In region I at252a, each of the comparators206aand206boutputs a high state and logic circuit208controls output transistor210to output a low state in the output signal at220. In region II at252b, first comparator206aoutputs a low state and second comparator206boutputs a high state, and logic circuit208controls output transistor210to output a high state. In region III at252c, first and second comparators206aand206boutput low states and logic circuit208outputs a low state.

Sensor system200senses the strength of a magnetic field, such as a magnetic field from a sensed object and/or an external magnet, and indicates the strength of the magnetic field via more than two regions. Sensor system200provides a logical output signal via logic circuit208in sensor system200. Using sensor system200in a security system application can improve security.

FIG. 7is a diagram illustrating one embodiment of a sensor system300that senses the position of an object (not shown) and indicates the position of the object in one of four regions. In one embodiment, sensor system300is a magnetic field position sensor. In one embodiment, sensor system300is a radio frequency (RF) position sensor. In one embodiment, sensor system300is part of a gear shift assembly. In other embodiments, sensor system300senses and indicates the position of an object in one region of n number of regions.

Sensor system300includes a sensor circuit302, an amplifier304, a comparator306, a logic circuit308, two output transistors310aand310b, and a multiplexer312. Sensor circuit302is electrically coupled to the inputs of amplifier304via sensed signal paths314aand314band the output of amplifier304is electrically coupled to comparator306via input signal path316.

Sensor circuit302senses the object and provides sensed signals to amplifier304via sensed signal paths314aand314b. Amplifier304receives the sensed signals at314aand314band provides an amplified input signal to comparator306via input path316, where the amplified input signal at316corresponds to the sensed signals at314aand314b. In one embodiment, sensor circuit302is a magnetic sensor circuit. In one embodiment, sensor circuit302is an inductive sensor circuit. In one embodiment, sensor circuit302is a capacitive sensor circuit. In one embodiment, sensor circuit302is a Hall-effect sensor circuit. In one embodiment, sensor circuit302is a magneto-resistive (XMR) sensor circuit.

Multiplexer312receives three threshold voltages V1, V2, and V3. Multiplexer312receives threshold voltage V1at318, threshold voltage V2at320, and threshold voltage V3at322. Also, multiplexer312receives control signal CNTRL at324from control logic (not shown for clarity), such as a controller, a microprocessor, or another logic circuit. The output of multiplexer312is electrically coupled to a threshold voltage input of comparator306via threshold voltage path326. Control signal CNTRL at324controls multiplexer312to provide each of the three different threshold voltages V1, V2, and V3to comparator306.

Comparator306receives the input signal at316and compares the input signal at316to the threshold voltages V1, V2, and V3provided via multiplexer312. Comparator306is electrically coupled to logic circuit308via comparator output path328and comparator306provides an output signal to logic circuit308via comparator output path328for each comparison to one of the three threshold voltages V1, V2, and V3. Thus, if multiplexer312provides the three different threshold voltages V1, V2, and V3to comparator306over a given period of time, comparator306provides three output signals to logic circuit308over the same given period of time. In other embodiments, sensor system300includes n threshold voltages and comparator306compares the input signal at316to n threshold voltages and provides n corresponding output signals to logic circuit308.

Comparator306receives threshold voltage V1at326via multiplexer312and compares the input signal at316to the first threshold voltage V1. If the input signal at316is above the first threshold voltage V1, comparator306provides a first output signal at328in one state, such as a low state. If the input signal at316is below the first threshold voltage V1, comparator306provides the first output signal at328in another state, such as a high state.

Comparator306receives threshold voltage V2at326via multiplexer312and compares the input signal at316to the second threshold voltage V2. If the input signal at316is above the second threshold voltage V2, comparator306provides a second output signal at328in one state, such as a low state. If the input signal at316is below the second threshold voltage V2, comparator306provides the second output signal at328in another state, such as a high state.

Comparator306receives threshold voltage V3at326via multiplexer312and compares the input signal at316to the third threshold voltage V3. If the input signal at316is above the third threshold voltage V3, comparator306provides a third output signal at328in one state, such as a low state. If the input signal at316is below the third threshold voltage V1, comparator306provides the third output signal at328in another state, such as a high state.

Logic circuit308receives the first, second, and third output signals at328and control signal CNTRL at324. Logic circuit308provides logical output signals that indicate which one of the four regions the sensed object is in. Logic circuit308is electrically coupled to the input of first output transistor310avia logic output path330aand to the input of second output transistor310bvia logic output path330b. First output transistor310ahas a first output at332aand is electrically coupled to a reference, such as ground, at334. Second output transistor310bhas a second output at332band is electrically coupled to a reference, such as ground, at336. In other embodiments, logic circuit308provides other signals that indicate which region the sensed object is in, signals such as pulse width modulated (PWM) signals, local interconnect network (LIN) signals, and/or controller area network (CAN) signals.

Logic circuit308receives the three output signals at328and provides two logical output signals at330aand330bthat indicate which one of four regions the object is in. The first logical output signal at330acontrols first output transistor310aand the second logical output signal at330bcontrols second output transistor310bto output first and second output signals at332aand332b, respectively. In other embodiments, logic circuit308receives n comparator output signals and logic circuit308provides logical output signals to indicate which one of n+1 regions the object is in.

In operation, the sensed object is in one of four regions, where the first region is furthest away from sensor system300, the second region is closer to sensor system300than the first region but further away from sensor system300than the third region, the third region is closer to sensor system300than the second region but further away from sensor system300than the fourth region, and the fourth region is closest to sensor system300.

If the sensed object is in the first region, the input signal at316that corresponds to the sensed signals at314aand314bis below the first, second, and third threshold voltages V1, V2, and V3and comparator306outputs three high states. If the sensed object is in the second region, the input signal at316is above the first threshold voltage V1and below the second and third threshold voltages V2and V3, such that comparator306outputs a low state via the comparison to the first threshold voltage V1and high states via the comparisons to the second and third threshold voltages V2and V3. If the sensed object is in the third region, the input signal at316is above the first and second threshold voltages V1and V2and below the third threshold voltage V3, such that comparator306outputs low states via the comparisons to the first and second threshold voltages V1and V2and a high state via the comparison to the third threshold voltage V3. If the sensed object is in the fourth region, the input signal at316is above the first, second, and third threshold voltages V1, V2, and V3and comparator306outputs three low states.

Logic circuit308receives the comparator output signals at328and control signal CNTRL at324and outputs two logical output signals at330aand330b, which control output transistors310aand310bto provide output signals at332aand332b. If the sensed object is in the first region, logic circuit308controls output transistors310aand310bto output high states in the output signals at332aand332b. If the sensed object is in the second region, logic circuit308receives the one low state and two high states and controls output transistor310ato output a high state and output transistor310bto output a low state. If the sensed object is in the third region, logic circuit308receives the two low states and the one high state and controls output transistor310ato output a low state and output transistor310bto output a high state. If the sensed object is in the fourth region, logic circuit28receives the three low states and controls output transistors30aand30bto output low states.

In other embodiments, sensor system300has n number of different threshold voltages. The input signal at316is compared via the n threshold voltages to produce n comparator output signals. Logic circuit308receives the n comparator output signals and indicates which region of up to n+1 regions the sensed object is in.

Sensor system300senses the sensed object in one of more than two regions. Using sensor system300reduces the number of sensors and wiring, which reduces system costs.