Device for providing parallel filtering

Abstract

In at least one embodiment, a system comprising a first circuit and a second circuit is provided. The first circuit includes a first filter that filters a first input signal and generates a first filtered output signal. The first circuit includes a first comparator that compares the first filtered output signal to a first threshold and provides a first output signal indicative of an error condition to one or more first processors. The second circuit includes a second filter that filters the first input signal and generates a second filtered output signal, filtering the first input signal in a shorter time than the first filter requires to filter the first input signal.The second circuit includes a second comparator that compares the second filtered output signal to a second threshold and provides a second output signal indicative of the error condition to one or more second processors.

Description

Technical FieldAspects disclosed herein relate generally to a system for providing parallel filtering. These and other aspects are discussed in greater detail below.Brief Description of the DrawingsFIG. 1 shows an apparatus for providing parallel filtering according to an embodiment. FIG. 2 shows an equivalent circuit and illustrates how the first time constant and the second time constant are determined according to an embodiment. FIG. 3 shows various measurements of sensed voltage and response times for disabling a charging operation.DETAILED DESCRIPTIONEmbodiments of the present invention will be described in detail below, but it should be noted that the described embodiments are merely exemplary of the invention that may also be embodied by various alternative embodiments. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of particular components. The details of construction and function described herein are not to be interpreted as limiting, but merely as a representative basis for one skilled in the art who seeks to practice the present invention.Reference will now be made to embodiments, examples of which are shown in the accompanying drawings. In the following detailed description, numerous details are set forth in order to clarify the embodiments. However, it should be apparent to those skilled in the art that the embodiments described herein may be practiced without these specific details. Furthermore, well-known methods, procedures, components, circuits, and networks will not be described in detail in order not to unnecessarily obscure the relevant aspects of the embodiments.It should be appreciated that the embodiments described herein are merely exemplary and that numerous alternative embodiments are also possible. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of particular components. The details of construction and function described herein are not to be interpreted as limiting, but merely as a representative basis for one skilled in the art who seeks to practice the present invention.For example, phrases "one or more," "at least one" may be a function performed by one element, a function performed by more than one element, and e.g., distributed, multiple functions performed by one element, multiple functions performed by multiple elements, or any combination thereof.Various elements may be designated by enumerations such as "first", "second", etc., but the elements are in no way limited by these designations. The terms are used merely to distinguish the elements from one another. For example, a first contact may also be referred to as a second contact and a second contact may also be referred to as a first contact, without departing from the scope of the invention. The first contact and the second contact are both contacts, but not the same contact.The terminology used for describing the various embodiments is intended to be illustrative of particular embodiments and is not to be taken in a limiting sense. Where the description of the various embodiments and in the claims use singular formulations, each may also be a plurality of the stated units, unless this is clearly excluded by the context. Furthermore, "and / or" means all possible combinations of one or more of the elements mentioned in connection therewith. And, when used in the specification, the words "include," "comprise," and / or "comprise," this refers to the presence of stated features, integers, steps, operations, elements, and / or components, but does not preclude one or more other features, integers, steps, operations, elements, components, and / or groups thereof from possibly being present.The conjunction "when" is to be understood as meaning "when" or "at" or "in response to a determination" or "in response to a detection" depending on the context. Accordingly, a phrase with "when determining" or "when detecting a condition or event" may also be understood as "upon determining" or "in response to determining" or "upon detecting said condition or event" or "in response to detecting said condition or event", depending on the context.Aspects disclosed herein generally provide a system that performs parallel filtering for a sensing circuit. The sensing circuit senses an incoming voltage for, for example, an onboard charging device (OBC). The disclosed system includes a first circuit including at least one first filter and a second circuit including at least one second filter. The first circuit and the second circuit each receive a first input signal indicative of at least one sensed voltage condition in the system. The first filter is operated at a first operating frequency and the second filter is operated at a second operating frequency. The second operating frequency of the second filter is greater than the first operating frequency, thereby allowing the second circuit to detect a fault condition of the system faster than the first circuit requires for detecting the fault condition. Generally, the second circuit outputs an output signal for transmission to one or more processors (or microprocessors and / or digital signal processors (DSPs)) in the system to quickly deactivate the system for mitigation of the error condition.The first circuit also detects the fault condition, but the detection is made at a timing later than that of the second circuit for detecting the fault condition because the first operating frequency is less than the second operating frequency. In this case, the first circuit detects the fault condition for reporting the detected fault condition to other processors (e.g., in the vehicle for diagnostic purposes and / or for use as a redundant test on the first circuit). Therefore, it may not be necessary for the first circuit to detect the fault condition at the same rate as the second circuit.The first operating frequency for the first filter and the second operating frequency for the second filter are each based on a first time constant and a second time constant. As disclosed herein, there is a correlation between the electronics used to form the first circuit and the second circuit and the various time constants with which the first and second filters are operated. For example, the first time constant may be derived based on values for a first resistive and capacitive network of the first filter. Accordingly, the second time constant may be derived based on values for a second resistive and capacitive network of the second filter. Other implementations used to detect error conditions using parallel filtering techniques in a system utilize buffer circuits (or operational amplifiers) to isolate the filters from each other. No buffer circuits are required in the disclosed system. In addition, the disclosed system provides an error detection mechanism that can be applied to any number of applications having different delay times, alarm thresholds, responses to ramping, etc. In addition, the disclosed system may be well suited for applications that require redundant sensing mechanisms for providing a number of parallel measurements.FIG. 1 illustrates a system 100 (or apparatus) for providing parallel filtering and detecting fault conditions, according to an embodiment. The system 100 generally includes a first circuit 102 and a second circuit 104. It should be appreciated that the system 100 may include any number of circuits that operate similar to the first circuit 102 and / or the second circuit 104. Generally, the first circuit 102 and the second circuit 104 are each configured to detect fault conditions (or a single fault condition) (e.g., an overvoltage condition (OV), an undervoltage condition (UV), an overcurrent condition (OC), and / or an underflow condition (UC)) attributable to a detected input (e.g., a detected voltage or current). In one example, the system 100 detects fault conditions for an onboard charging device (OBC) 103 in a vehicle 105. It should be appreciated that the system 100 may be used for any application configured to detect a fault condition.The system 100 includes a sense input circuit 130 that provides a first input signal indicative of the sensed voltage to the first circuit 102 and the second circuit 104. The first circuit 102 includes a first filter 110 and a first comparator 114. A first resistive and capacitive network 113 generally forms the first filter 110. The first resistive and capacitive network 113 comprises a resistor R 1 and a capacitor C 1. In one example, the first filter 110 is a low pass filter. Note that the first filter 110 may also be a high pass filter, a band pass filter, etc. The first filter 110 filters the incoming sensed voltage and provides an output to the first comparator 114. The first comparator 114 compares the output from the first filter 110 with a threshold value, and then outputs a first output signal indicating a detected error based on the comparison.The first filter 110 operates at a first frequency when the filtering operation is performed. The relevance of the first frequency is explained in more detail below. The first circuit 102 provides an output (or first output signal) indicative of the presence of an error detection condition in the system 100 to one or more first processors 120 ("the first processor 120"). The first processor 120 may include one or more first microcontrollers or one or more first digital signal processors (DSPs). It should be noted that the first DSPs can be operated faster than the first microcontrollers. The first processor 120 reports the presence of a fault via a diagnostic function and may send an indication of the fault condition detected to alert users of the condition. The fault condition may correspond to an overvoltage condition (OV), an undervoltage condition (UV), an overcurrent condition (OC), or an underflow condition (UC). When an overcurrent condition or an underflow condition is detected, the first circuit 102 reports such a condition to the first DSPs because the first DSPs are responding faster than the first microcontrollers. When an overvoltage condition or an undervoltage condition is detected, the first circuit 102 reports such a condition to the first microcontrollers because faults with respect to overvoltage and undervoltage conditions may not have the same priority as the detected overcurrent and undercurrent conditions.Similarly, the second circuit 104 also provides an output (or the second output signal) to one or more second processors 122 (i.e., "the second processor 122") in response to detecting the fault condition. The second processor 122 may include one or more second microcontrollers or one or more second digital signal processors (DSPs). It should be noted that the second DSPs can be operated faster than the second microcontrollers. For example, the second circuit 104 receives the first input signal indicating the detected voltage (or current) in the system 100 from the detection input circuit 130. The second circuit 104 includes a second filter 112 aand a second comparator 116 a. A second resistive and capacitive network 115 generally forms the second filter 112a. The second resistive and capacitive network 115 comprises a resistor R 2 aand a capacitor C 2 a. In one example, the second filter 112 ais a low pass filter. Note that the second filter 112 amay also be a high pass filter, a band pass filter, etc. The second filter 112 afilters the incoming sensed voltage and provides an output (e.g., a second output signal) to the second comparator 116 a. The second comparator 116 acompares the output from the second filter 112 awith a threshold value, and then outputs the second output signal indicating a detected error based on the comparison.The second filter 112a operates at a second frequency when the filtering operation is performed. The second frequency may be greater than the first frequency used by the first filter 110. The second circuit 104 provides the second output signal to one or more second processors 122 that indicate the presence of the fault detection condition in the system 100. The second processor, in response to detecting the fault condition, deactivates the system 100 to prevent the fault condition from damaging electronic or other devices in the system 100. In an example, the second processor 122 (e.g., the second DSP) may deactivate the charging operation performed between the OBC 103 and the vehicle 105 within microseconds. The fault condition may correspond to an overvoltage condition (OV), an undervoltage condition (UV), an overcurrent condition (OC), or an underflow condition (UC).Generally, the second circuit 104 detects fault condition as quickly as possible because the second circuit 104 sends the second output signal to the second processor 122 to disable the system 100 (or the OBC 103) when a fault condition is detected. For example, the second processor 122 may control any number of DC-DC converters (not shown) that convert an incoming high voltage signal during a charging operation of the vehicle 105. Upon detecting or receiving the second output signal from the second circuit 104, the second processor 122 disables the battery charging operation due to the high voltage conversion performed to alleviate potential issues. The first processor 120 may, as mentioned above in connection with the first circuit 102, detect the presence or absence of a fault condition when receiving the first output signal from the first circuit 102, and notify other microprocessors (or controllers) in the vehicle 105 that a fault condition (e.g., an overvoltage condition or an undervoltage condition) has been detected in connection with the vehicle charging operation. The first processor 120 may not be directly responsible for controlling the various DC / DC converters performing the power conversion during battery charging operations, and may simply log the presence of the fault condition if that condition is present, so other actions may be taken. However, if the first circuit 102 is arranged to sense an overcurrent or undercurrent condition, then the first circuit 102 reports such a condition to the first microcontroller and the first DSP of the first processor 120. The first output signal output from the first circuit 102 may serve as a redundant output and may be used to disable the charging operation when the second processor 122 malfunctions.Thus, by operating the second filter 112 aof the second circuit 104 at a second frequency greater than the first frequency for the first circuit 102, the second circuit 104 is configured to process (e.g., filter the first input signal indicative of the sensed voltage or current with the second filter 112 a) faster than the first circuit 102 (e.g., faster than the first filter 110) and thus may sense an error condition earlier than the first circuit 102. The second circuit 104 may also report the fault condition to the second processor 122 more quickly than the first circuit 102 requires for reporting the fault condition to the first processor 120.The second circuit 104 includes a third filter 112 band a third comparator 116 b. The first filter 110, the second filter 112a, and the third filter 112b are all included in the system 100, because the filters 110, 112a, and 112b provide independent readings, respectively, and thus redundant measurement circuits. A third resistive and capacitive network 117 generally forms the third filter 112 b. The third resistive and capacitive network 117 comprises a resistor R 2 band a capacitor C 2 b. In one example, R2bis R2aand C2bis C2a. In another example, the third filter 112 bis a low pass filter. Note that the third filter 112 bmay also be a high pass filter, a band pass filter, etc. The third filter 112b filters the incoming sensed voltage and provides an output to the third comparator 116b. The third comparator 116 bcompares the output from the third filter 112 bwith a threshold value, and then outputs a third output signal indicating a detected error based on the comparison.The third filter 112b operates at a third frequency when performing the filtering operation. The third frequency may be greater than the first frequency used by the first filter 110. In an example, the third frequency may be similar (or equal) to the second frequency of the second filter 112 a. The third circuit 112 balso provides the third output signal indicating the presence of the fault condition in the system 100 to the second processor 122. As mentioned above, in response to detecting the fault condition, the second processor 122 disables the system 100 to prevent the fault condition from damaging electronic or other devices in the system 100.The second circuit 104 detects the fault condition as quickly as possible because the second circuit 104 sends the second output signal to the second processor 122 to disable the system 100 (or the OBC 103) when a fault condition is detected. By operating the third filter 112 bof the second circuit 104 at the second frequency that is greater than the first frequency for the first circuit 102, the second circuit 104 is configured for more rapid (or shorter time) processing (e.g., filtering the first input signal indicative of the sensed voltage with the second filter 112 a) than the first circuit 102 and thus for a previous sensing of the fault condition than by the first circuit 102. The second circuit 104 may also report the fault condition to the second processor 1022 faster than the first circuit 102 requires for reporting the fault condition to the first processor 120. In an example, the second processor 122 disables the OBC 103 based on receiving the second output signal from the second circuit 104 before the first processor 120 reports the fault condition based on receiving the first output from the first circuit 102 if the second filter 112 aand the third filter 112 bare operating at the second frequency (and also have a larger frequency range).Input threshold resistances Rin1, Rin2 and Rin3 for each of the first comparator 114, the second comparator 116a and the third comparator 116b provide a threshold voltage V TH( or a threshold current) for each of the first comparator 114, the second comparator 116a and the third comparator 116b. The resistance values for the input threshold resistors Rin 1, Rin 2, and Rin 3 may be selected such that the first comparator 114, the second comparator 116 a, and the third comparator 116 bmay provide an output indicative of an overvoltage condition, an undervoltage condition, the overcurrent condition, and / or the underflow condition. Two circuits 102 and 104 are shown, however, it should be appreciated that other numbers of circuits may also be included in the system 100 to provide a plurality of outputs corresponding to a sensed overvoltage condition.Generally, the operating frequencies (e.g., the first frequency for the first filter 110, the second frequency for the second filter 112 a, and the third frequency for the third filter 112 b) may be calculated by the following equation, which is a function of the time constant (e.g., "τ"):The selection of certain resistance and capacitance values (e.g., R1and C1) for the first resistive capacitive network (113) at least partially forms the first frequency (or f 1). Accordingly, the particular resistance and capacitance values (e.g., R2a, C2a and R2b, C2b) for the second and third capacitive networks 115 and 117 at least partially form the second frequency for the second filter 112 aand the third filter 112 b. In one example, the second filter 112 aand the third filter 112 bmay both operate at the second frequency. Here, the resistance value for R 2 aand the capacitance value for C 2 aof the second resistive and capacitive network 115 are equal to the resistance value for R 2 band the capacitance value for C 2 bof the third resistive and capacitive network 117. In another example, the second filter 112 aand the third filter 112 bmay be operated at different frequencies, respectively, but may still be configured to be operated faster than the first filter 113. In this case, the resistance values for R 2 aand R 2 bmay be different in each case and / or the capacitance values for C 2 aand C 2 bmay be different in each case. By selecting the various values for the resistive and capacitive networks for the first filter 110, the second filter 112 a, and / or the third filter 112 to obtain the desired frequencies for controlling the speed at which the first circuit 102 and the second circuit 104 measure the sensed voltage, such an implementation provides a higher performance and does not require additional electronic devices, thus being cost effective.FIG. 2 shows an equivalent circuit 200 indicating how a first time constant (e.g., τ 1) and a second time constant (e.g., τ 2) are determined, according to an embodiment. The first frequency for the first filter 110 is based on the first time constant (e.g., τ 1). Accordingly, the second frequency for the second filter 112 aand the third filter 112 bis based on the second time constant (e.g., τ 2), assuming that the second filter 112 aand the third filter 112 bare operating at the same frequency. As mentioned above, the second filter 112 aand the third filter 112 bmay be operated at different frequencies, respectively, as long as these frequencies allow a faster operation (performing the filtering operation) of the second filter 112 aand the third filter 112 bthan with the first filter 110.Circuit 200 generally corresponds to the aspects shown in connection with first circuit 102, second circuit 104, and sense input circuit 130. For example, circuit 200 includes resistors R 1, R 2, RD 1, and Rd 2 and capacitors C 1, C 2. The first time constant τ 1 is generally defined (or formed) based on the following equation: where R th= Rd | | Rd2The second time constant τ 2 is generally defined (or formed) based on the following equation: wherein C2=2*C2a and R2=R2a / 2Thus, the first time constant τ 1 and the second time constant τ 2 may be provided as follows: τ 1= C1*(R1), or τ 2= C2a*(R2a) (or τ 2= C2b*(R2b)). Thus, as shown, the various resistance values for resistors R1, R2a, Rd1, and Rd2 and the various capacitance values for capacitors C1 and C2a may be used to generate the first time constant and the second time constant based on the equations set forth above. The first time constant and the second time constant may be used based on the above equation (1) to derive the first frequency and the second frequency for the first filter 110 and the second filter 112 aand thus for the third filter 112 b. Thus, it should be appreciated that the first time constant is greater than the second time constant (or τ 1 > τ 2), such that the first frequency for the first filter 110 is less than the second frequency for the second filter 112 aand the third filter 112 b(e.g., for the second filter 112 a(or for the third filter 112 b)) such that they operate faster than the first filter 110.FIG. 3 shows a table 200 indicating various measurements of sensed voltage and response times for disabling a charging operation. Generally, the table 200 includes a first column 202, a second column 203, a third column 204, and a fourth column 206. The first column 202 generally corresponds to various sensed signals for voltages or currents. The second column 203 generally corresponds to different signal parameters. The third column 204 generally corresponds to first measurements performed by a system that does not include aspects of the indicated system 100. The fourth column 206 generally corresponds to second measurements performed by the indicated system 100.In one example, the detected signals in the first column 202 of the table 200 correspond to detected voltages or currents in a high voltage (HV) grid in the vehicle 105. In another example, the detected signals in the first column 202 of the table 200 correspond to detected voltages or currents in a low voltage network (LV) in the vehicle 105. The second column 203 shows various parameters corresponding to the sensed characteristics (e.g., voltage or current). The third column 204 shows different measurement times of another system (not shown of system 100) for each of the sensed voltages and each of the sensed currents in the first column 202. The fourth column 206 shows different measurement times of the first circuit 102 of the system 100 for each of the sensed voltages and each of the sensed currents in the first column 202.As generally indicated at reference number 250, the other system measures the sensed voltage across the high voltage grid at 51 μs, while the system 100 (or second circuit 104) described herein measures the sensed voltage across the high voltage grid generally at 12 μs. As generally indicated at reference number 252, the other system measures / senses the sensed current at the high voltage grid at 356 μs, while the system 100 (or second circuit 104) described herein measures / senses the sensed current at the high voltage grid at 33 μs. As generally indicated at reference number 254, the other system measures the sensed voltage generally at the low voltage grid at 736 μs, while the system 100 (or second circuit 104) described herein measures / senses the sensed voltage at the low voltage grid generally at 28 μs. As generally indicated at reference numeral 256, the other system measures / senses the sensed current at the high voltage grid generally at 202 μs, while the system 100 (or second circuit 104) described herein measures / senses the sensed current at the high voltage grid at 40 μs. Thus, in various cases, the system 100 has a faster response time than the other system.Item 1: A system includes a first circuit and a second circuit. The first circuit includes a first filter that filters a first input signal indicative of at least one sensed voltage condition in the system, the first filter generating a first filtered output signal in response to filtering the first input signal at a first frequency. The first circuit includes a first comparator that compares the first filtered output signal to a first threshold and provides a first output signal indicative of an error condition to one or more first processors for reporting the error condition based on the comparison of the first filtered output signal to the first threshold. The second circuit includes a second filter that filters the first input signal indicative of at least the sensed voltage condition in the system, the second filter generating a second filtered output signal in response to filtering the first input signal at a second frequency greater than the first frequency, such that the second filter can filter the first input signal in a shorter time than the first filter requires for filtering the first input signal. The second circuit includes a second comparator that compares the second filtered output signal to a second threshold and provides a second output signal indicative of the fault condition to one or more second processors that disable the system before the one or more first processors report the fault condition based on the comparison of the second filtered output signal to the second threshold.Item 2: According to Item 1, the second circuit includes a third filter that filters the first input signal indicating at least the detected voltage condition, the third filter generating a third filtered output signal in response to filtering the first input signal at the second frequency greater than the first frequency, so that the second filter can filter the first input signal in a shorter time than the first filter requires for filtering the first input signal.Item 3: According to item 2, the second circuit includes a third comparator that compares the third filtered output signal to a third threshold and provides a third output signal indicative of the fault condition to the one or more second processors based on a comparison of the second filtered output signal to the third threshold voltage, wherein the one or more second processors disable the system before the one or more first processors report the fault condition.Item 4: According to Item 3, the third threshold value for the third comparator is different from the second threshold value for the second comparator.Item 5: According to Item 4, the second comparator outputs a signal indicating an overvoltage condition based on the comparison of the second filtered output signal with the second threshold.Item 6: According to item 4, the third comparator outputs a signal indicating an under voltage condition based on the comparison of the third filtered output signal with the third threshold value.Item 7: According to Item 1, the first frequency for the first filter is based on a first time constant and the second frequency for the second filter is based on a second time constant, wherein the first time constant is different from the second time constant.Item 8: According to item 7, the first time constant is larger than the second time constant.Item 9: According to Item 7, the system further comprises a sense input circuit comprising at least one sense resistor electrically connected to the first filter and the second filter and providing the first input signal indicative of the sensed voltage condition.Item 10: According to item 9, the first time constant and the second time constant are each partially based on a resistance value of the at least one sensing resistor.Item 11: According to item 7, the first filter is formed by a first resistive and capacitive network and the second filter is formed by a second resistive and capacitive network.Item 12: According to item 11, the first time constant is based at least in part on a first resistance value and a first capacitance value of the first resistive and capacitive network, and the second time constant is based at least in part on a second resistance value and a second capacitance value of the second resistive and capacitive network.Item 13: According to Item 1, the first filter is a low pass filter.Item 14. According to Item 1, the second filter is a low pass filter.Item 15: A system includes a first circuit and a second circuit. The first circuit includes a first filter that filters a first input signal indicative of at least one sensed voltage condition, the first filter generating a first filtered output signal in response to filtering the first input signal at a first frequency, and a first comparator that compares the first filtered output signal to a first threshold and provides a first output signal indicative of a fault condition to one or more first processors for reporting the fault condition based on the comparison of the first filtered output signal to the first threshold. The second circuit includes a second filter that filters the first input signal indicative of at least the sensed voltage condition in the system, the second filter providing a second filtered output signal in response to filtering the first input signal at a second frequency greater than the first frequency, such that the second filter can filter the first filter signal in a shorter time than the first filter requires for filtering the first input signal. The second circuit includes a second comparator that compares the second filtered output signal to a second threshold and provides a second output signal indicative of the fault condition to one or more second processors. The first frequency of the first filter is based at least on a first time constant and the second frequency of the second filter is based at least on a second time constant, wherein the second time constant is less than the first time constant, such that the second filter filters the first input signal in a shorter time than the first filter requires for filtering the first input signal.Item 16: According to item 15, the system includes a sense input circuit including at least one sense resistor electrically connected to the first filter and the second filter and providing the first input signal indicative of the sensed voltage condition.Item 17: According to item 16, the first time constant and the second time constant are each partially based on a resistance value of the at least one sensing resistor.Item 18: According to item 15, the first filter is formed by a first resistive and capacitive network and the second filter is formed by a second resistive and capacitive network.Item 19: According to claim 18, the first time constant is based at least in part on a first resistance value and a first capacitance value of the first resistive and capacitive network, and the second time constant is based at least in part on a second resistance value and a second capacitance value of the second resistive and capacitive network.Item 20: A system includes a first filter, a first comparator, and a second filter. The first filter filters a first input signal indicative of at least one sensed voltage condition in the system, the first filter generating a first filtered output signal in response to filtering the first input signal at a first frequency. The first comparator compares the first filtered output signal to a first threshold and provides a first output signal indicative of an error condition to one or more first processors for reporting the error condition based on the comparison of the first filtered output signal to the first threshold. The second filter filters the first input signal indicative of at least the sensed voltage condition in the system, the second filter generating a second filtered output signal in response to filtering the first input signal at a second frequency different from the first frequency, such that the second filter can filter the first input signal in a shorter time than the first filter requires for filtering the first input signal. The second comparator compares the second filtered output signal to a second threshold and provides a second output signal indicative of the fault condition to one or more second processors that disable the system before the one or more first processors report the fault condition based on the comparison of the second filtered output signal to the second threshold.While exemplary embodiments have been described above, the invention is not limited to the embodiments described herein. The description is to be understood as exemplary and not restrictive, and various changes may be made in the embodiments described herein without departing from the scope of the invention. In addition, features of various embodiments may be combined to form further embodiments of the invention.

Claims

A system comprising: a first circuit comprising: a first filter that filters a first input signal indicative of at least one sensed voltage condition in the system, the first filter generating a first filtered output signal in response to filtering the first input signal at a first frequency; and a first comparator that compares the first filtered output signal to a first threshold and provides a first output signal indicative of an error condition to one or more first processors for reporting the error condition based on the comparison of the first filtered output signal to the first threshold; and a second circuit comprising: a second filter that filters the first input signal indicative of at least the sensed voltage condition in the system, the second filter filtering a second filtered output signal in response to filtering the first input signal at a second frequency, The second filter generates the first input signal in a shorter time than the first filter requires for filtering the first input signal, and a second comparator that compares the second filtered output signal to a second threshold and provides a second output signal indicative of the fault condition to one or more second processors that disable the system before the one or more first processors report the fault condition based on the comparison of the second filtered output signal to the second threshold.The system of claim 1, wherein the second circuit comprises a third filter that filters the first input signal indicative of at least the sensed voltage condition, the third filter generating a third filtered output signal in response to filtering the first input signal at the second frequency greater than the first frequency, such that the second filter can filter the first input signal in a shorter time than the first filter requires for filtering the first input signal.The system of claim 2, wherein the second circuit comprises a third comparator that compares the third filtered output signal to a third threshold and provides a third output signal indicative of the fault condition to the one or more second processors based on a comparison of the second filtered output signal to the third threshold voltage, wherein the one or more second processors disable the system before the one or more first processors report the fault condition.The system of claim 3, wherein the third threshold for the third comparator is different than the second threshold for the second comparator.The system of claim 4, wherein the second comparator outputs a signal indicative of an overvoltage condition based on the comparison of the second filtered output signal to the second threshold.The system of claim 4, wherein the third comparator outputs a signal indicative of an under voltage condition based on the comparison of the third filtered output signal with the third threshold.The system of claim 1, wherein the first frequency for the first filter is based on a first time constant and the second frequency for the second filter is based on a second time constant, wherein the first time constant is different than the second time constant.The system of claim 7, wherein the first time constant is greater than the second time constant.The system of claim 7, further comprising a sense input circuit comprising at least one sense resistor electrically connected to the first filter and the second filter and providing the first input signal indicative of the sensed voltage condition.The system of claim 9, wherein the first time constant and the second time constant are each based in part on a resistance value of the at least one sensing resistor.The system of claim 7, wherein the first filter is formed by a first resistive and capacitive network and the second filter is formed by a second resistive and capacitive network.The system of claim 11, wherein the first time constant is based at least in part on a first resistance value and a first capacitance value of the first resistive and capacitive network, and wherein the second time constant is based at least in part on a second resistance value and a second capacitance value of the second resistive and capacitive network.The system of claim 1, wherein the first filter is a low pass filter.The system of claim 1, wherein the second filter is a low pass filter.A system comprising: a first circuit comprising: a first filter that filters a first input signal indicative of at least one sensed voltage condition, the first filter generating a first filtered output signal in response to filtering the first input signal at a first frequency; and a first comparator that compares the first filtered output signal to a first threshold and provides a first output signal indicative of an error condition to one or more first processors for reporting the error condition based on the comparison of the first filtered output signal to the first threshold; and a second circuit comprising: a second filter that filters the first input signal indicative of at least the sensed voltage condition in the system, the second filter filtering a second filtered output signal in response to filtering the first input signal at a second frequency, The second filter is configured to filter the first filter signal in a shorter time than the first filter is required for filtering the first input signal, and a second comparator configured to compare the second filtered output signal with a second threshold and provide a second output signal indicative of the error condition to one or more second processors, wherein the first frequency of the first filter is based at least on a first time constant and the second frequency of the second filter is based at least on a second time constant, and wherein the second time constant is less than the first time constant, such that the second filter filters the first input signal in a shorter time than the first filter is required for filtering the first input signal.The system of claim 15, comprising a sense input circuit comprising at least one sense resistor electrically connected to the first filter and the second filter and providing the first input signal indicative of the sensed voltage condition.The system of claim 16, wherein the first time constant and the second time constant are each based in part on a resistance value of the at least one sensing resistor.The system of claim 15, wherein the first filter is formed by a first resistive and capacitive network and the second filter is formed by a second resistive and capacitive network.The system of claim 18, wherein the first time constant is based at least in part on a first resistance value and a first capacitance value of the first resistive and capacitive network and the second time constant is based at least in part on a second resistance value and a second capacitance value of the second resistive and capacitive network.A system comprising: a first filter that filters a first input signal indicative of at least one sensed voltage condition in the system, the first filter generating a first filtered output signal in response to filtering the first input signal at a first frequency; and a first comparator that compares the first filtered output signal to a first threshold and provides a first output signal indicative of an error condition to one or more first processors for reporting the error condition based on the comparison of the first filtered output signal to the first threshold; a second filter that filters the first input signal indicative of at least the sensed voltage condition in the system, the second filter generating a second filtered output signal in response to filtering the first input signal at a second frequency different than the first frequency, such that the second filter may filter the first input signal in a shorter time than the first filter requires filtering the first input signal, and provides a second comparator that compares the second filtered output signal to a second threshold and a second output signal indicative of the fault condition to one or more second processors that disable the system before the one or more first processors report the fault condition based on the comparison of the second filtered output signal to the second threshold.

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