Multi-gain channels for multi-range sensor

A current sensor including: a sensing unit including one or more sensing elements, the sensing unit being arranged to generate, at least in part, an internal signal, the internal signal being generated in response to a magnetic field, the magnetic field being produced, at least in part, by an electrical current that is sensed with the sensing unit; a first signal processing path coupled to the sensing unit, the first signal processing path including a first compensation unit for adjusting the internal signal, the first signal processing path being configured to generate a first signal based on the internal signal; a second signal processing path coupled to the sensing unit, the second signal processing path including a second compensation unit for adjusting the internal signal, the second path having a different sensitivity than the first path.

BACKGROUND

As is known, sensors are used to perform various functions in a variety of applications. Some sensors include one or magnetic field sensing elements, such as a Hall effect element or a magnetoresistive element, to sense a magnetic field associated with proximity or motion of a target object, such as a ferromagnetic object in the form of a gear or ring magnet, or to sense a current, as examples. Sensor integrated circuits are widely used in automobile control systems and other safety-critical applications. There are a variety of specifications that set forth requirements related to permissible sensor quality levels, failure rates, and overall functional safety.

SUMMARY

According to aspects of the disclosure, a current sensor is provided, comprising: a sensing unit including one or more sensing elements, the sensing unit being arranged to generate, at least in part, an internal signal, the internal signal being generated in response to a magnetic field, the magnetic field being produced, at least in part, by an electrical current that is sensed with the sensing unit; a first signal processing path coupled to the sensing unit, the first signal processing path including a first compensation unit for adjusting the internal signal, the first signal processing path being configured to generate a first signal based on the internal signal, the first signal being indicative of a value of the electrical current, the first signal having a first error with respect to a first range of values of the electrical current; a second signal processing path coupled to the sensing unit, the second signal processing path including a second compensation unit for adjusting the internal signal, the second signal processing path being configured to generate a second signal based on the internal signal, the second signal being indicative of the value of the electrical current, the second signal having a second error with respect to the first range of values of the electrical current, wherein the second error is lower than the first error.

According to aspects of the disclosure, a current sensor is provided, comprising: a sensing unit including one or more sensing elements, the sensing unit being arranged to generate, at least in part, an internal signal, the internal signal being generated in response to a magnetic field, the magnetic field being produced, at least in part, by an electrical current that is sensed with the sensing unit; a first signal processing path coupled to the sensing unit, the first signal processing path including a first compensation unit for adjusting the internal signal, the first signal processing path being configured to generate a first signal based on the internal signal, the first signal being indicative of a value of the electrical current, the first signal having a first error with respect to a first range of values of the electrical current; a second signal processing path coupled to the sensing unit, the second signal processing path including a second compensation unit for adjusting the internal signal, the second signal processing path being configured to generate a second signal based on the internal signal, the second signal being indicative of the value of the electrical current, the second signal processing path having a second error with respect to a second range of values of the electrical current; and a combiner configured to generate an output signal based on at least one of the first signal and the second signal.

According to aspects of the disclosure, a current sensor is provided, comprising: a sensing unit including one or more sensing elements, the sensing unit being arranged to generate, at least in part, an internal signal, the internal signal being generated in response to a magnetic field, the magnetic field being produced, at least in part, by an electrical current that is sensed with the sensing unit; a first signal processing path coupled to the sensing unit, the first signal processing path including a first compensation unit for adjusting the internal signal, the first signal processing path being configured to generate a first signal based on the internal signal, the first signal being indicative of a value of the electrical current, the first signal processing path having a first sensitivity to the internal signal; a second signal processing path coupled to the sensing unit, the second signal processing path including a second compensation unit for adjusting the internal signal, the second signal processing path being configured to generate a second signal based on the internal signal, the second signal being indicative of the value of the electrical current, the second signal processing path having a second sensitivity to the internal signal.

According to aspects of the disclosure, a sensor is provided, comprising: a sensing unit including one or more sensing elements, the sensing unit being arranged to generate, at least in part, an internal signal, the internal signal being generated in response to a magnetic field; a first signal processing path coupled to the sensing unit, the first signal processing path including a first means for adjusting the internal signal, the first signal processing path being configured to generate a first signal based on the internal signal, the first signal being indicative of a value of the magnetic field, the first signal having a first error with respect to a first range of values of the magnetic field; a second signal processing path coupled to the sensing unit, the second signal processing path including a second means for adjusting the internal signal, the second signal processing path being configured to generate a second signal based on the internal signal, the second signal being indicative of a value of the magnetic field, the second signal having a second error with respect to the first range of values of the magnetic field.

DETAILED DESCRIPTION

According to aspects of the disclosure, a current sensor is disclosed for use in automated control systems. The current sensor may be used to generate one or more control signals, as needed. The current sensor includes at least a first signal processing path and a second signal processing path. Both signal processing paths are coupled to the same sensing element or set of sensing elements. Each signal processing path has different sensitivities, or gains for different ranges of the current that is being measured. The first signal processing path may have a higher sensitivity (than the second signal processing path) in a low range of values of the current being measured. The second signal processing path may have a higher sensitivity (than the first signal processing path) in a high range of values of the current being measured. The outputs of the first and second paths may be routed to different output terminals (or sets of output terminals) of the current sensor. This gives electronic designers the flexibility to use the output of the first signal processing path, when the current being measured is in the low range, and use the output of the second signal processing path when the current being measured is in the low range. According to the present example, the low range may include a range having a lower bound of L1and an upper bound of U1. The high range may include a range having a lower bound of L2and an upper bound or U2,wherein at L2>L1. In some implementations, the low and high range may overlap (e.g., when U1>L2,etc.). According to another aspect of the disclosure, the current sensor may include an on-die combiner that is configured to combine the outputs of the first and second signal processing paths to produce a combined signal. The combined signal may be equal to the output of the first signal processing path when the current being measured is in the low range. On the other hand, the combined signal may be equal to the second signal when the current being measured is in the high range. The combined signal may be output on one or more output terminals of the current sensor. Across the full range of values of the current that is being measured, the combined signal may have lower overall error than any of the outputs of the first and second signal processing paths. In this regard, outputting the combined signal may help increase the accuracy of the current sensor, while maintaining the pinout of conventional (and less-accurate) current sensors. Having a legacy pinout is advantageous because it could permit the current sensor to be integrated into existing electronic circuits that are designed with conventional (and less-accurate) current sensors in mind. Furthermore, generating such a combined signal can achieve a more accurate sensor output over a wider dynamic range of sensed current values so that a current sensor can accurately accommodate sensing currents that might heretofore require the purchase of different sensors.

The examples of current sensors that are provided throughout the disclosure include two signal processing paths only. However, it will be understood that the concepts and ideas of the present disclosure are not limited to any specific count of signal processing paths being present in a current sensor, for as long as: (i) each of the signal processing paths is associated with a different range of values of the current being measured, and (ii) each of the signal processing paths has a higher sensitivity than the rest for values of the current that fall within the range that is associated with the signal processing path.

FIG.1Ais a diagram of an example of a current sensor100, according to aspects of the disclosure. As illustrated, the current sensor100may include a sensing unit101, a dynamic offset cancelation unit102, a signal processing path110A, a signal processing path110B, and a diagnostic circuit120. The sensing unit101may include one or more magnetic field sensing elements, and a frequency chopper that is configured to chop a signal that is generated by the magnetic field sensing elements to produce a signal103. The dynamic offset cancellation unit may demodulate the signal103(at the frequency of the chopper) to produce a signal104. The signal processing path110A may process the signal104to generate a signal107A. The signal processing path110B may process the signal104to generate an output put signal107B. The diagnostic circuit120may be configured to detect discrepancies in the operation of the signal processing path110A and the signal processing path110B to detect the presence of a failure. The diagnostic circuit120may output a diagnostic signal124. When the diagnostic signal124is set to a first value, this may indicate that the signal processing path110A and/or the signal processing path110B has failed. When the diagnostic signal124is set to a second value, this may indicate that the signal processing path110A and/or the signal processing path110B are operating correctly.

The signal processing path110A may include a frontend amplifier111A, a conditioning unit112A, an output driver113A, a compensation unit114A, and an offset control unit115A. The frontend amplifier111A may amplify the signal104to produce a signal105A. The conditioning unit112A may filter the signal105A to produce a signal106A. And the output driver113A may generate the signal107A based on the signal106A.

The compensation unit114A may include any suitable type of electronic circuitry that is configured to adjust the gain of the frontend amplifier111A. In some implementations, the compensation unit114A may be configured to perform temperature compensation in a well-known fashion. Additionally or alternatively, in some implementations, the compensation unit114A may perform humidity compensation, pressure compensation, and/or any other suitable type of compensation. Stated succinctly, the present disclosure is not limited to any specific implementation of the compensation unit114A.

The conditioning unit112A may include one or more filters for filtering the signal105A. By way of example, the conditioning unit112A may include a low-pass filter, a moving average filter (e.g., a sinc filter, etc.), and/or any other suitable type of filter. Stated succinctly, the present disclosure is not limited to any specific implementation of the conditioning unit112A.

The offset control unit115A may include any suitable type of electronic circuitry that is configured to set the offset of the output driver113A. In operation, the offset control unit115A may generate a signal116A that specifies the offset of output driver113A. The signal116A may be generated in a well-known fashion by the offset control unit115A. In some implementations, the signal116A may be arranged to compensate for the effects of various environmental factors, such as temperature, humidity, pressure, etc.

The signal processing path110B may include a frontend amplifier111B, a conditioning unit112B, an output driver113B, a compensation unit114B, and an offset control unit115B. The frontend amplifier111B may amplify the signal104to produce a signal105B. The conditioning unit112B may filter the signal105B to produce a signal106B. And the output driver113B may generate the signal107B based on the signal106B.

The compensation unit114B may include any suitable type of electronic circuitry that is configured to adjust the gain of the frontend amplifier111B. In some implementations, the compensation unit114B may be configured to perform temperature compensation in a well-known fashion. Additionally or alternatively, in some implementations, the compensation unit114B may perform humidity compensation, pressure compensation, and/or any other suitable type of compensation. Stated succinctly, the present disclosure is not limited to any specific implementation of the compensation unit114B.

The conditioning unit112B may include one or more filters for filtering the signal105B. By way of example, the conditioning unit112B may include a low-pass filter, a moving average filter (e.g., a sinc filter, etc.), and/or any other suitable type of signal. Stated succinctly, the present disclosure is not limited to any specific implementation of the conditioning unit112B.

The offset control unit115B may include any suitable type of electronic circuitry that is configured to set the offset of the output driver113B. In operation, the offset control unit115B may generate a signal116B that specifies the offset of output driver113B. The signal116B may be generated in a well-known fashion by the offset control unit115B. In some implementations, the signal116B may be arranged to compensate for the effects of various environmental factors, such as temperature, humidity, pressure, etc.

FIG.1Bshows a plot of a curve130, which shows the response of the sensing unit101to an electric current that is being measured with current sensor100. The Y-axis of the plot represents the value (in volts) of the signal104and the X-axis represents the value of the current that is being measured by the current sensor100.FIG.1Billustrates that: (i) the signal104may have a value VAL_1when the value of the current is −2500A; (ii) the signal104may have a value VAL_2when the value of the current is −500A; (iii) the signal104may have a value VAL_3 when the value of the current is +500A; (iv) the signal104may have a value VAL_4 when the value of the current is +2500A. The current values of −2500A, −500A, 500A, and 2500A are provided as an example. It will be understood that each of the values VAL_1, VAL_2, VAL_3, and VAL-4 may correspond to any value of the current being measured.

FIG.1Cis a plot of curves142and144. Curve142represents the value of the signal107A across a set of values of the signal104, and curve144represents the value of the signal107B across the same set of values of the signal104.FIG.1Cshows that the signal processing path110B may have a higher sensitivity than the first signal path110A for values of the signal104that fall in the range of [VAL_2-VAL_3]. It will be recalled that the range [VAL_2-VAL_3] corresponds to current values in the range of [−500A-+500A].FIG.1Cfurther shows that the signal processing path110A may have lower sensitivity than the first signal path110B for values of the signal104that fall in the range [VAL_1-VAL_2]. It will be recalled that the range of [VAL_1-VAL_2] corresponds to current values in the range of [−2500A-500A].FIG.1Cfurther shows that the signal processing path110A may have lower sensitivity than the signal processing path110B for values of the signal104that fall in the range [VAL_3-VAL_4]. It will be recalled that the range of [VAL_3-VAL_4] corresponds to current values in the range of [+500A-+2500A]. The signal107B, as illustrated inFIG.1C, is flat for values of the signal104in the ranges [VAL_1-VAL_2] and [VAL_3-VAL-4] because the signal processing path110B is in a saturation area for those values.

FIG.1Dis a plot of curves152A and152B, according to one example. Curve152A represents the error of signal107A and curve152B represents the error of signal107B. Together curves152A and152B show that, when the current being measured by the current sensor100is in the range of 0-500A, the signal107B may have lower error than the signal107A. Furthermore, the curves152A and152B show that, when the current being measured by the current sensor100is in the range of 500-2500A, the signal107B may have a higher error than the signal107A]FIG.1D, in other words, illustrates that the signal processing paths110A and110B may have different errors for different current ranges. It will be understood that the present disclosure is not limited to any specific bounds for the different current ranges. For example, in some implementations, in some implementations, the range of the first signal processing path110A may be entirely within the range of the signal processing path110B. In such implementations, the range of signal processing path110A may have a lower bound that is higher than the lower bound of the range of the signal processing path110B, and the range of the signal processing path110A may have an upper bound that is lower than the upper bound of the signal processing path110B.

To achieve different sensitivities and error curves for the signal processing paths110A-B, the signal processing path110A and the signal processing path110B may be configured differently. For example, in some implementations, the frontend amplifiers111A and111B may have different linear response regions. Additionally or alternatively, in some implementations, the compensation units114A and114B may be configured to adjust the gain of the signal104by a different factor. Additionally or alternatively, in some implementations, the offset control units115A and115B may be configured to adjust signals106A and106B, respectively, by a different coefficient. Additionally or alternatively, in some implementations, the conditioning units112A and112B may have different response functions. Those of ordinary skill in the art will readily recognize, after reading this disclosure, that there are various ways to configure the signal processing paths110A and110B to have different error curves for the same current range. Furthermore, it will be understood that the present disclosure is not limited to any specific method for configuring the signal processing paths110A and110B to have different error curves (and/or sensitivities) for different current ranges. In some respects, each of signal processing paths110A and110B may have a gain that is designed to sense a respective range currents and is optimized to have less error for the range of currents.

The diagnostic circuit120may include a rescaler121and a diagnostic unit123. The rescaler121may include electronic circuitry that is configured to receive the signal105B as input and produce a rescaled signal122. The diagnostic unit123may include any suitable type of electronic circuitry that is configured to compare the rescaled signal122to the signal107A and output a diagnostic signal124based on an outcome of the comparison. For instance, if the rescaled signal122and the signal107A match, the diagnostic unit123may set the diagnostic signal124to a value that indicates that the current sensor100is operating correctly (e.g., ‘1’). By contrast, if the rescaled signal122and the signal107A do not match, the diagnostic unit123may set the diagnostic signal124to a value that indicates that the current sensor100is not operating correctly (e.g., ‘0’).

FIG.2Ais a diagram of an example of a current sensor200, according to aspects of the disclosure. The current sensor200is similar to the current sensor100in that it includes two different signal paths, which receive an input signal that is generated by the same sensing unit, and which have different sensitivities. The current sensor200differs from the current sensor100in that each of the signal paths of the current sensor200is configured to output a digital signal, whereas the signal processing paths of the current sensor100output analog signals. Another difference between the current sensor200and the current sensor100is that the current sensor200outputs a combined signal that is produced by combining the signals generated by its signal processing paths, whereas the current sensor100outputs the signals that are generated by its signal processing paths, without combining these signals beforehand.

As illustrated the current sensor200may include a sensing unit101, a dynamic offset cancelation unit102, a signal processing path210A, a signal processing path210B, a combiner230, an output interface240, and a diagnostic circuit220.

The sensing unit101, as noted above with respect toFIG.1A, may include one or more magnetic field sensing elements, and a frequency chopper that is configured to chop a signal that is generated by the magnetic field sensing elements to produce the signal103. The dynamic offset cancellation unit102, as noted above with respect toFIG.1A, may demodulate the signal103(at the frequency of the chopper) to produce the signal104. The signal processing path220A may process the signal104to generate a signal207A. The signal processing path210B may process the signal104to generate a signal207B. The combiner230may combine the signals207A and207B to produce a signal208, which is subsequently output by the output interface240. The output interface240may include an I2C interface and/or any other suitable type of interface.

The signal processing path210A may include a frontend amplifier211A, a conditioning unit212A, an analog-to-digital converter (ADC)213A, and a compensation unit214A. The frontend amplifier211A may amplify the signal104to produce a signal205A. The conditioning unit212A may filter the signal205A to produce a signal206A. The ADC213A may digitize the signal206A to produce a signal207A, which is subsequently provided to the combiner230.

The conditioning unit212A may include one or more filters for filtering the signal205A. By way of example, the conditioning unit212A may include a low-pass filter, a moving average filter (e.g., a sinc filter, etc.), and/or any other suitable type of signal. Stated succinctly, the present disclosure is not limited to any specific implementation of the conditioning unit212A.

The compensation unit214A may include any suitable type of electronic circuitry that is configured to adjust the gain of the frontend amplifier211A. In some implementations, the compensation unit214A may be configured to perform temperature compensation in a well-known fashion. Additionally or alternatively, in some implementations, the compensation unit214A may perform humidity compensation, pressure compensation, and/or any other suitable type of compensation. Stated succinctly, the present disclosure is not limited to any specific implementation of the compensation unit214A.

The signal processing path220B may include a frontend amplifier211B, a conditioning unit212B, an analog-to-digital converter (ADC)213B, and a compensation unit214B. The frontend amplifier211B may amplify the signal204to produce a signal205B. The conditioning unit212B may filter the signal205B to produce a signal206B. The ADC213B may digitize the signal206B to produce a signal207B, which is subsequently provided to the combiner230.

The conditioning unit212B may include one or more filters for filtering the signal205B. By way of example, the conditioning unit212B may include a low-pass filter, a moving average filter (e.g., a sinc filter, etc.), and/or any other suitable type of signal. Stated succinctly, the present disclosure is not limited to any specific implementation of the conditioning unit212B.

The compensation unit214B may include any suitable type of electronic circuitry that is configured to adjust the gain of the frontend amplifier211B. In some implementations, the compensation unit214B may be configured to perform temperature compensation in a well-known fashion. Additionally or alternatively, in some implementations, the compensation unit214B may perform humidity compensation, pressure compensation, and/or any other suitable type of compensation. Stated succinctly, the present disclosure is not limited to any specific implementation of the compensation unit214B.

FIG.2Cis a plot260of curves262A and262B, according to one example. Curve262A represents the error of signal207A and curve262B represents the error of signal207B. Together curves262A and262B show that, when the current being measured by the current sensor200is in the range of 0-500A, the signal207B may have lower error than the signal207A. Furthermore, the curves262A and262B show that, when the current being measured by the current sensor200is in the range of 500-2500A, the signal207B may have a higher error than the signal207B.FIG.2C, in other words, illustrates that the signal processing paths210A and210B may have different sensitives for different current ranges. It will be understood that the present disclosure is not limited to any specific bounds for the different current ranges.

To achieve different sensitivities and error curves for the signals207A and207B, the signal processing path210A and the signal processing path210B may be configured differently. For example, in some implementations, the frontend amplifiers211A and211B may have different linear response regions. Additionally or alternatively, in some implementations, to achieve different error curves for the signals207A and207B, the compensation units214A and214B may be configured to adjust the gain of the signal204by a different factor. Additionally or alternatively, in some implementations, to achieve different error curves for the signals207A and207B, the conditioning units212A and212B may have different response functions. Those of ordinary skill in the art will readily recognize, after reading this disclosure, that there are various ways to configure the signal processing paths210A and210B to have different error curves for the same current range. Furthermore, it will be understood that the present disclosure is not limited to any specific method for configuring the signal processing paths210A and210B to have different error curves (and/or sensitivities) for different current ranges. In some respects, each of signal processing paths210A and210B may have a gain that is designed to sense a respective range currents and is optimized to have less error for the range of currents.

The combiner230, may include any suitable type of electronic circuitry that is configured to combine the signals207A and207B to produce the signal208. More particularly, the signal208may be equal to (or otherwise based on) the signal207B when the value of the current being measured is less than a predetermined value (e.g., 500A). Moreover, under the same arrangement, the signal208may be equal to (or otherwise based on) the signal207A when the value of the current being measured is greater than a predetermined value (e.g., 500A).FIG.2Bshows a plot of a curve242, which relates the signal208to different values of the current that is being measured by the current sensor200. The curve242includes portions244A and244B. As noted above, in some implementations, values of the signal208that fall within the portion244A may be generated based on the signal207A (but not based on the signal207B). Similarly, values of the signal208that fall within the portion244B may be generated based on the signal207B. In operation, when at least one of the signals207A and207B indicates that the value of the current being measured is below a predetermined value (e.g., 500A), the combiner230may set the signal208to equal the signal207B. On the other hand, when at least one of the signals207A and207B indicates that the value of the current being measured is above the predetermined value (e.g., 500A), the combiner230may set the signal208to equal the signal207A. In some implementations, the combiner230may also adjust the offset of the signal208before the signal208is provided to the output interface240.

Returning toFIG.2A, the diagnostic circuit220may include a rescaler221, an ADC223, and a diagnostic unit225. The rescaler121may include electronic circuitry that is configured to receive the signal205B as input and produce a rescaled signal222. The rescaled signal222may be digitized by the ADC to produce a signal224. If the current sensor200is operating correctly, the signal224may match the signal207B. On the other hand, if the current sensor200is experiencing a failure, the signal224would not match the signal207B. The diagnostic unit225may include any suitable type of electronic circuitry that is configured to compare the signal224to the signal207B and generate a diagnostic signal227based on an outcome of the comparison. For instance, if the rescaled signal222and the signal207B match, the diagnostic unit225may set the diagnostic signal227to a value that indicates that the current sensor200is operating correctly (e.g., ‘1’). By contrast, if the signal224and the signal207B do not match, the diagnostic unit225may set the diagnostic signal227to a value that indicates that the current sensor200is not operating correctly (e.g., ‘0’).

FIG.3Ais a diagram of an example of a current sensor300, according to aspects of the disclosure. The current sensor300is similar to the current sensor200in that two different signal paths, receive an input signal that is generated by the same sensing unit and have different sensitivities. However, unlike the current sensor200, one of the signal processing paths of the current sensor300includes a digitizing unit that is configured to (i) offset (in the analog domain) an analog signal to fit within the dynamic range of an ADC that is arranged to digitize the analog signal and (ii) de-offset (in the digital domain) the output of the ADC by the same amount in order to return the digitized signal back to the original level of the analog signal.

The current sensor300may include a sensing unit101, a dynamic offset cancelation unit102, a signal processing path310A, a signal processing path310B, a combiner330, an output interface340, and a diagnostic unit350.

The sensing unit101, as noted above with respect to FIG.1A, may include one or more magnetic field sensing elements, and a frequency chopper that is configured to chop a signal that is generated by the magnetic field sensing elements to produce the signal103. The dynamic offset cancellation unit102, as noted above with respect toFIG.1A, may demodulate the signal103(at the frequency of the chopper) to produce the signal104. The signal processing path220A may process the signal104to generate a signal307A. The signal processing path310B may process the signal104to generate a signal307B. The combiner330may combine the signals307A and307B to produce a signal308, which is subsequently output by the output interface340. The output interface340may include an I2C interface and/or any other suitable type of interface.

The signal processing path310A may include a frontend amplifier311A, a conditioning unit322A, an analog-to-digital converter (ADC)313A, and a compensation unit314A. The frontend amplifier311A may amplify the signal104to produce a signal305A. The conditioning unit312A may filter the signal305A to produce a signal306A. The ADC313A may digitize the signal306A to produce a signal307A, which is subsequently provided to the combiner330.

The conditioning unit312A may include one or more filters for filtering the signal305A. By way of example, the conditioning unit312A may include a low-pass filter, a moving average filter (e.g., a sinc filter, etc.), and/or any other suitable type of signal. Stated succinctly, the present disclosure is not limited to any specific implementation of the conditioning unit312A.

The compensation unit314A may include any suitable type of electronic circuitry that is configured to adjust the gain of the frontend amplifier311A. In some implementations, the compensation unit314A may be configured to perform temperature compensation in a well-known fashion. Additionally or alternatively, in some implementations, the compensation unit314A may perform humidity compensation, pressure compensation, and/or any other suitable type of compensation. Stated succinctly, the present disclosure is not limited to any specific implementation of the compensation unit314A.

The signal processing path320B may include a frontend amplifier311B, a conditioning unit322B, a digitizing unit313B, and a compensation unit314B. The frontend amplifier311B may amplify the signal104to produce a signal305B. The conditioning unit312B may filter the signal305B to produce a signal306B. The digitizing unit313B may digitize the signal306B to produce the signal307B, which is subsequently provided to the combiner230.

The conditioning unit312B may include one or more filters for filtering the signal305B. By way of example, the conditioning unit312may include a low-pass filter, a moving average filter (e.g., a sinc filter, etc.), and/or any other suitable type of signal. Stated succinctly, the present disclosure is not limited to any specific implementation of the conditioning unit312B.

The compensation unit314B may include any suitable type of electronic circuitry that is configured to adjust the gain of the frontend amplifier311B. In some implementations, the compensation unit314B may be configured to perform temperature compensation in a well-known fashion. Additionally or alternatively, in some implementations, the compensation unit314B may perform humidity compensation, pressure compensation, and/or any other suitable type of compensation on the signal104. Stated succinctly, the present disclosure is not limited to any specific implementation of the compensation unit314B.

The digitizing unit313B may include an offsetting unit320, an ADC322, and a de-offsetting unit324. The offsetting unit320may identify an offset value based on a scale factor signal302that is provided to digitizing unit313B by the combiner330. The offsetting unit320may then subtract the offset value from the signal306B to produce a signal321. The ADC322may digitize the signal321to produce a signal323. The de-offsetting unit324may determine the offset value based on the scale factor signal302. The de-offsetting unit324may then add the offset value to the signal323to produce the signal307B. In some respect, subtracting the offset value from the signal306B may allow the offset version of signal306A (i.e., the signal321) to fit within the linear range of the ADC322. After the offset version of the signal306B is digitized (i.e., after the signal323is produced), adding the offset value back to the digitized and offset version of the signal (i.e., adding the offset value to the signal323) may return the digitized version of the signal back to the original value of the signal. In some respects, using the offsetting unit320and the de-offsetting unit324may help in simplifying the design of the ADC322, as well as the sensor300. Specifically, the offsetting unit allows the signal that is input into the ADC to always remain in the linear range of the ADC and never clip. Without the offsetting unit320and the de-offsetting unit324, the linear range of the ADC322would have to be as wide as the signal to be measured, which can be difficult to achieve without compromising resolution and linearity.

FIG.3Bshows the offsetting unit320in further detail. As illustrated, the offsetting unit320may include a lookup table342and a subtraction unit344. The lookup table342may be configured to map each of a plurality of scale factor values to a respective offset value. The lookup table342may receive the scale factor signal302and output an offset value343that corresponds to the scale factor that is represented by the scale factor signal302. The subtraction unit344may receive the signal306B and the offset value343as input. The subtraction unit344may subtract the offset value343from the signal306B to produce the signal321. According to the example ofFIG.3B, the subtraction unit344is implemented in the analog domain.

FIG.3Cshows the de-offsetting unit324in further detail. As illustrated, the de-offsetting unit324may include a lookup table351and an addition unit354. The lookup table351may be configured to map each of a plurality of scale factor values to a respective offset value. The lookup table351may receive the scale factor signal302and output an offset value353that corresponds to the scale factor that is represented by the scale factor signal302. The offset value353may be the same as the offset value343. The addition unit354may receive the signal323and the offset value353as input. The addition unit354may add the offset value353to the signal323to produce the signal307B. According to the example ofFIG.3C, the addition unit354is implemented in the digital domain.

In some implementations, the scale factor and offset value may be determined in accordance with Equations 1 and 2 below:

where R is the range of the signal processing path310B and signal307Ais the value of signal307A. The range R of the signal processing path may be between 0 and VAL3. It will be recalled that VAL3 is the value of signal307B when the current being measured by the sensing element101is equal to 500A. In other words, in some implementations, the scale factor may be equal (or otherwise based on) the number of times the signal307A exceeds the range R of the signal processing path310B.

The combiner330may include any suitable type of electronic circuitry that is configured to combine the signals307A and307B to produce the signal308. More particularly, the signal308may be equal to (or otherwise based on) the signal307B when the value of the current being measured is less than a predetermined value (e.g., 500A). Furthermore, the signal308may be equal to (or otherwise based on) the signal307A when the value of the current being measured is greater than a predetermined value (e.g., 500A).FIG.3Dshows a plot of a curve362which relates the signal308to different values of the current that is being measured by the current sensor300. The curve362includes portions362A and362B. As noted above, in some implementations, values of the signal308that fall within the portion362A may be generated based on the signal307A (but not based on the signal307B). Similarly, values of the signal308that fall within the portion362B may be generated based on the signal307B. In operation, when at least one of the signals307A and307B indicates that the value of the current being measured is below a predetermined value (e.g., 500A), the combiner330may set the signal308to equal the signal207B. On the other hand, when at least one of the signals307A and307B indicates that the value of the current being measured is above the predetermined value (e.g., 500A), the combiner330may set the signal308to equal the signal307A. In some implementations, the combiner330may also adjust the offset of the signal308before the signal308is provided to the output interface340.

FIG.3Eis a plot370of curves372A and372B, according to one example. Curve372A represents the error of the signal307A and curve372B represents the error of the signal307B. Together curves372A and372B show that, when the current being measured by the current sensor300is in the range of 0-500A, the signal307B may have lower error than the signal307A. Furthermore, the curves372A and372B show that, when the current being measured by the current sensor300is in the range of 500-2500A, the signal307B may have a higher error than the signal307A.FIG.3E, in other words, illustrates that the signal processing paths310A and310B may have different sensitives for different current ranges. It will be understood that the present disclosure is not limited to any specific bounds for the different current ranges.

To achieve different sensitivities and error curves for the signals307A and307B, the signal processing path310A and the signal processing path310B may be configured differently. For example, in some implementations, the frontend amplifiers311A and311B may have different linear response regions. Additionally or alternatively, in some implementations, to achieve different error curves for the signals307A and307B, the compensation units314A and314B may be configured to adjust the gain of the signal104by a different factor. Additionally or alternatively, in some implementations, to achieve different error curves for the signals307A and307B, the conditioning units312A and312B may have different response functions. Those of ordinary skill in the art will readily recognize, after reading this disclosure, that there are various ways to configure the signal processing paths310A and310B to have different error curves for the same current range. Furthermore, it will be understood that the present disclosure is not limited to any specific method for configuring the signal processing paths310A and310B to have different error curves (and/or sensitivities) for different current ranges. In some respects, each of signal processing paths110A and110B may have a gain that is designed to sense a respective range currents and is optimized to have less error for the range of currents.

The diagnostic unit350may include any suitable type of electronic circuitry that is configured to compare the signal307A to the signal307B and generate a diagnostic signal352based on an outcome of the comparison. For instance, if a difference between signals307A and307B is within a predetermined threshold, the diagnostic unit350may set the diagnostic signal352to a first value (e.g., 1′). On the other hand, if the difference between signals307A and307B exceeds the threshold, the diagnostic unit350may set the diagnostic signal352to a second value (e.g., ‘0’). The diagnostic signal350may be used to detect the occurrence of a failure in the current sensor300.

According to the present disclosure, each of the circuits shown inFIGS.1A,2A, and3Bis an integrated circuit that is formed on a single die and is housed in the same semiconductor packaging. However, alternative implementations are possible in which any of the circuits is a discrete circuit or a circuit that is formed on more than one semiconductor die. Stated succinctly, the present disclosure is not limited to any specific implementations of the circuits shown inFIGS.1A,2A, and3A.

The concepts and ideas discussed throughout the disclosure are not limited to current sensors in particular. For example, the circuits shown inFIGS.1A,2A, and3Acan be part of linear position sensors, speed sensors, angular position sensors, and/or any other suitable type of sensor. According to the present disclosure, the signal processing paths discussed with respect toFIGS.1A,2A and3Aare coupled to a set of magnetic field sensing elements. However, alternative implementations are possible in which the signal processing paths are coupled to another type of sensing element(s) such as optical sensing element(s), pressure sensing element(s), temperature sensing element(s), etc.

The term “unit” as used throughout the present disclosure shall refer to an electronic component and/or an electronic circuit that include one or more electronic components. In some implementations, the electronic components may include analog components (e.g., electronic components that operate in the analog domain). Additionally or alternatively, in some implementations, the electronic components may include digital logic and/or electronic components that operate in the digital domain. Additionally or alternatively, in some implementations, the electronic components may include digital logic that is configured to execute a sensor firmware. It will be understood that the meaning of the term “compensation unit” includes, but not limited to the examples provided throughout the disclosure. It will be understood that the meaning of the term “conditioning unit” includes, but not limited to the examples provided throughout the disclosure. It will be further understood that the meaning of the term “offsetting unit” includes, but not limited to the examples provided throughout the disclosure. It will be further understood that the meaning of the term “de-offsetting unit” includes, but not limited to the examples provided throughout the disclosure. Stated succinctly, the term “unit,” as used throughout the disclosure is not intended to be construed as means-plus-function language.

The system may be implemented, at least in part, via a computer program product, (e.g., in a non-transitory machine-readable storage medium such as, for example, a non-transitory computer-readable medium), for execution by, or to control the operation of, data processing apparatus (e.g., a programmable processor, a computer, or multiple computers). Each such program may be implemented in a high-level procedural or object-oriented programming language to work with the rest of the computer-based system. However, the programs may be implemented in assembly, machine language, or Hardware Description Language. The language may be a compiled or an interpreted language, and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or another unit suitable for use in a computing environment. A computer program may be deployed to be executed on one computer or multiple computers at one site or distributed across multiple sites and interconnected by a communication network. A computer program may be stored on a non-transitory machine-readable medium that is readable by a general or special purpose programmable computer for configuring and operating the computer when the non-transitory machine-readable medium is read by the computer to perform the processes described herein. For example, the processes described herein may also be implemented as a non-transitory machine-readable storage medium, configured with a computer program, where upon execution, instructions in the computer program cause the computer to operate in accordance with the processes. A non-transitory machine-readable medium may include but is not limited to a hard drive, compact disc, flash memory, non-volatile memory, volatile

According to the present disclosure, a magnetic field sensing element can include one or more magnetic field sensing elements, such as Hall effect elements, magnetoresistance elements, or magnetoresistors, and can include one or more such elements of the same or different types. As is known, there are different types of Hall effect elements, for example, a planar Hall element, a vertical Hall element, and a Circular Vertical Hall (CVH) element. As is also known, there are different types of magnetoresistance elements, for example, a semiconductor magnetoresistance element such as Indium Antimonide (InSb), a giant magnetoresistance (GMR) element, for example, a spin valve, an anisotropic magnetoresistance element (AMR), a tunneling magnetoresistance (TMR) element, and a magnetic tunnel junction (MTJ). The magnetic field sensing element may be a single element or, alternatively, may include two or more magnetic field sensing elements arranged in various configurations, e.g., a half bridge or full (Wheatstone) bridge. Depending on the device type and other application requirements, the magnetic field sensing element may be a device made of a type IV semiconductor material such as Silicon (Si) or Germanium (Ge), or a type III-V semiconductor material like Gallium-Arsenide (GaAs) or an Indium compound, e.g., Indium-Antimonide (InSb).