Abstract:
Systems, methods and media for current monitoring are provided herein. An exemplary method may include: receiving a temperature of a power MOSFET, the temperature being sensed by a temperature sensor; determining a resistance of the power MOSFET using the received temperature; receiving a voltage across the power MOSFET, the voltage being measured by a differential amplifier; calculating a current provided to an electrical load by the power MOSFET using the determined resistance of the power MOSFET and the received voltage; comparing the calculated current to a predetermined threshold; and switching the power MOSFET to an off state in response to the calculated current exceeding the predetermined threshold.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation application of, and claims the priority benefit of, U.S. patent application Ser. No. 14/586,784 filed on Dec. 30, 2014. The subject matter of the aforementioned application is incorporated herein by reference in its entirety for all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present technology pertains to monitoring, and more specifically to current monitoring. 
       BACKGROUND ART 
       [0003]    Electricity is essential to electronic devices, such as portable/wearable computer and communications systems, home appliances, entertainment systems, office equipment, industrial robots, server farms/data centers, telecommunications equipment, military systems, marine electronics, and the like. Monitoring the amount of current delivered to a system/load is critical for understanding, for example, the system&#39;s impact on battery life, safety decisions in over-current protection circuits, the system&#39;s health, and establishing system and subsystem power budgets/allowances. 
       SUMMARY OF THE INVENTION 
       [0004]    In some embodiments, the present technology is directed to a system for current monitoring which may include an electrical load; a power MOSFET electrically coupled to the electrical load; a differential amplifier electrically coupled to the power MOSFET; a temperature sensor thermally coupled to the power MOSFET; a processor communicatively coupled to the differential amplifier and the temperature sensor; and a memory communicatively coupled to the processor. The memory mays store instructions executable by the processor to perform a method comprising: receiving a temperature of the power MOSFET, the temperature being sensed by the temperature sensor, determining a resistance of the power MOSFET using the received temperature, receiving a voltage across the power MOSFET, the voltage being measured by the differential amplifier, calculating a current provided to the electrical load by the power MOSFET using the determined resistance of the power MOSFET and the received voltage, comparing the calculated current to a predetermined threshold, and switching the power MOSFET to an off state in response to the calculated current exceeding the predetermined threshold. 
         [0005]    In some embodiments, the present technology is directed to a method for monitoring current performed by a processor. The method may include receiving a temperature of a power MOSFET, the temperature being sensed by a temperature sensor; determining a resistance of the power MOSFET using the received temperature; receiving a voltage across the power MOSFET, the voltage being measured by a differential amplifier; calculating a current provided to an electrical load by the power MOSFET using the determined resistance of the power MOSFET and the received voltage; comparing the calculated current to a predetermined threshold; and switching the power MOSFET to an off state in response to the calculated current exceeding the predetermined threshold. 
         [0006]    In some embodiments, the present technology is directed to a non-transitory computer-readable storage medium having embodied thereon instructions, the instructions being executable by a processor to perform a method for current monitoring. The method may include receiving a temperature of a power MOSFET, the temperature being sensed by a temperature sensor; determining a resistance of the power MOSFET using the received temperature; receiving a voltage across the power MOSFET, the voltage being measured by a differential amplifier; calculating a current provided to an electrical load by the power MOSFET using the determined resistance of the power MOSFET and the received voltage; comparing the calculated current to a predetermined threshold; and switching the power MOSFET to an off state in response to the calculated current exceeding the predetermined threshold. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The accompanying drawings, where like reference numerals refer to identical or functionally similar elements throughout the separate views, together with the detailed description below, are incorporated in and form part of the specification, and serve to further illustrate embodiments of concepts that include the claimed disclosure, and explain various principles and advantages of those embodiments. The methods and systems disclosed herein have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
           [0008]      FIG. 1A  is a simplified diagram of a system, according to some embodiments. 
           [0009]      FIG. 1B  is a simplified diagram of a system, according to various embodiments. 
           [0010]      FIG. 2  is a simplified diagram illustrating current monitoring in a system, according to some embodiments. 
           [0011]      FIG. 3A  is a simplified diagram illustrating current monitoring in a system, according to various embodiments. 
           [0012]      FIG. 3B  is a chart illustrating an effect of temperature on a switch characteristic, according to some embodiments. 
           [0013]      FIG. 3C  is a chart illustrating an effect of temperature on current monitoring accuracy, according to some embodiments. 
           [0014]      FIG. 3D  is a simplified schematic of circuits, according to some embodiments. 
           [0015]      FIG. 4  is a simplified diagram illustrating temperature-compensated current monitoring in a system, according to some embodiments. 
           [0016]      FIG. 5  is a simplified diagram illustrating temperature-compensated current monitoring in a system, according to various embodiments. 
           [0017]      FIG. 6  is a simplified diagram illustrating various aspects of a system for temperature-compensated current monitoring, according to some embodiments. 
           [0018]      FIG. 7  is a flow diagram of a method for temperature-compensated current monitoring, according to some embodiments. 
           [0019]      FIG. 8  is a simplified block diagram of a computing system, according to some embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    While this technology is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail several specific embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the technology and is not intended to limit the technology to the embodiments illustrated. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the technology. As used herein, the singular forms “a,” “an,” and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that like or analogous elements and/or components, referred to herein, may be identified throughout the drawings with like reference characters. It will be further understood that several of the figures are merely schematic representations of the present technology. As such, some of the components may have been distorted from their actual scale for pictorial clarity. 
         [0021]      FIG. 1A  shows system  100  including power apparatus  130  and load  120 . Power apparatus  130  is electrically coupled to load  120 . In some embodiments, power apparatus  130  is, for example, a power supply and/or a power distribution unit. A power supply is an electronic device that supplies electric energy to an electrical load, such as load  120 . Power supplies convert one form of electrical energy to another; power supplies may also be referred to as electric power converters. A power distribution unit is an apparatus for distributing and controlling electrical power (e.g., to one or more of load  120 ) and can include multiple electrical outlets. 
         [0022]    Power apparatus  130  may include power filtering, intelligent load balancing, and/or remote monitoring and control (e.g., turning individual loads on and/or off) functions. Power apparatus  130  may further include a main breaker, individual circuit breakers, and power monitoring panel (not illustrated in  FIG. 1A ). Power apparatus  130  can be in an enclosure (not depicted in  FIG. 1A ). The enclosure of power apparatus  130  may made of metal and include openings for a power monitoring panel, power input receptacle, and/or power outlets. A power monitoring panel may provide output to a user (e.g., status information, notifications, warnings, etc.) and receive input from the user. For example, the power monitoring panel includes at least some of the features of a computing system described in relation to  FIG. 8 . An enclosure of power apparatus  130  may include shielding to at least partially block electromagnetic interference (EMI; also called radio-frequency interference (RFI) when in radio frequency). 
         [0023]    Power apparatus  130  includes switch  110 . Switch  110  can turn on and/or off electrical power provided by power apparatus  130  to load  120 . Switch  110  includes three terminals: control input  116 , power input  114 , and power output  118 . Control input  116  controls the operation/state of switch  110  (e.g., “on” and/or “off”). Electrical power is received by switch  110  at power input  114 . For example, electrical power received at power input  114  is in the range of 24-32 Volts and 50-150 Amps. Switch  110  may turn on and/or off electrical power provided to load  120  through power output  118 . For example, electrical power provided at power output  118  is in the range of 24-32 Volts and 50-150 Amps. 
         [0024]    Load  120  is an electrical device which receives electrical power from power apparatus  130 . For example, load  120  can be one or more of portable/wearable computer and communications system, home appliance, home entertainment system, office equipment, industrial robot, server (server farm/data center), telecommunications equipment, military systems, marine electronics, avionics, and the like. 
         [0025]    As shown in  FIG. 1B , switch  110  ( FIG. 1A ) may be a power metal-oxide semiconductor field-effect transistor (MOSFET)  110   a . Power MOSFET  110   a  includes three terminals: drain  114   a , gate  116   a , and source  118   a , which may correspond to power input  114 , control input  116 , and power output  118  of switch  110 , respectively. A power MOSFET is a type of MOSFET designed to handle significant power levels. For example, power MOSFET  110   a  receives and/or provides electricity in the range of 24-32 Volts and 50-150 Amps. In some embodiments, power provided at source  118   a  is approximately the same as the power received at drain  114   a  (e.g., voltage provided at source  118   a  is based on a voltage received at gate  116   a  and a drop voltage of a body diode intrinsic to power MOSFET  110   a ). Power MOSFET  110   a  is, by way of non-limiting example, an Infineon IPT007N06N. Although MOSFET  110   a  as depicted in  FIG. 1B  is an n-channel (nmos or n-type) power MOSFET, various embodiments may use a p-channel (pmos or p-type) power MOSFET. 
         [0026]    Drain  114   a  is electrically coupled to a power or voltage source (not shown in  FIG. 1B ). Source  118   a  is electrically coupled to electric load  120 . Load  120  is electrically coupled to ground  140 . In this way, power MOSFET  110   a  is in a high-side configuration, source  118   a  not having a direct connection to ground  140 . A low-side configuration, where electric load  120  is coupled to drain  114   a  and source  118   a  is coupled to the ground, may also be used. 
         [0027]    Various aspects of power apparatus  130 , including power MOSFET  110   a , according to various embodiments are described further in relation to  FIG. 6 . 
         [0028]      FIG. 2  depicts system  200  for current monitoring using shunt resistor  210 , according to some embodiments. Shunt resistor  210  is disposed between switch  110  and load  120 . Since shunt resistor  210  is in series with load  120 , a voltage V SHUNT  is generated across shunt resistor  210  that is proportional to a current provided to load  120  I LOAD . In other words, using Ohm&#39;s Law, I LOAD  can be determined using the resistance of shunt resistor  210  and V SHUNT . Ohm&#39;s law states that the current through a conductor between two points is directly proportional to the potential difference across the two points, where a resistance of the conductor is the proportionality term. V SHUNT  can be measured by differential amplifier  220 . Differential amplifier  220 , by way of non-limiting example, is one or more of a current shunt monitor (CSM), operational amplifier (op-amp), difference amplifier (DA), instrumentation amplifier (IA), and the like. 
         [0029]    Current monitoring using shunt resistor  210  suffers from the disadvantage of reduced efficiency arising from power loss incurred through shunt resistor  210 . For example, a 0.001 Ohms resistance (of shunt resistor  210 ) will consume 2.5 Watts (producing heat) at 50 Amps. In addition, the additional heat (produced by shunt resistor  210 ) can shorten the life of electrical devices, including power apparatus  130 , so higher costs associated with further thermal management may be incurred. 
         [0030]      FIG. 3A  illustrates system  300  for current monitoring using a characteristic series resistance of switch  110  (e.g., power MOSFET  110   a ) R DS , according to some embodiments. When MOSFET  110   a  is conducting (e.g., power is provided to load  120  by power apparatus  130 ), MOSFET  110   a  is in a triode region of operation and acts as a linear resistor having resistance R DS . For example, R DS  is the resistance between drain  114   a  and source  118   a  of MOSFET  110   a . For example, V DS  is the voltage across MOSFET  110   a  (e.g., voltage across drain  114   a  and source  118   a  of MOSFET  110   a ). V DS  can be measured by differential amplifier  320 . Differential amplifier  320 , by way of non-limiting example, is one or more of a current shunt monitor (CSM), operational amplifier (op-amp), difference amplifier (DA), instrumentation amplifier (IA), and the like. Using Ohm&#39;s Law, I LOAD  can be determined using V DS  and R DS . 
         [0031]    The R DS  of MOSFET  110   a  is a strong function of temperature.  FIG. 3B  shows an example graph  350  of R DS  over temperature. As shown in  FIG. 3B , R DS  is from 0.00108 Ohms-0.00126 Ohms over temperatures from −40° C. to +140° C. At lower temperatures R DS  is a smaller value and at higher temperatures R DS  is a larger value. 
         [0032]    Since R DS  changes with temperature, the accuracy of current monitoring—using R DS  values based on temperature assumptions—is severely reduced.  FIG. 3C  shows an example graph  370  of current calculated at temperature from −40° C. to +140° C. For example, the current calculated assuming a 40° C. temperature has only a ±8% accuracy over the −40° C. to +140° C. temperature range. 
         [0033]      FIG. 3D  shows a non-limiting example of (simulation) circuits  390  which may be used to determine R DS  and I LOAD  (e.g., as shown in  FIGS. 3B and 3C ), according to some embodiments. 
         [0034]      FIG. 4  shows system  400  for temperature-compensated current monitoring, including power apparatus  130  and load  120 . Power apparatus  130  includes power MOSFET  110   a , temperature sensor  410 , differential amplifier  420 , and processor  430 . Temperature sensor  410  is thermally coupled to power MOSFET  110   a . Temperature sensor  410  and power MOSFET  110   a  are described further in relation to  FIG. 6 . Differential amplifier  420  is electrically coupled to power MOSFET  110   a . Processor  430  is communicatively coupled to temperature sensor  410  and differential amplifier  420 . 
         [0035]    Temperature sensor  410  determines a temperature of power MOSFET  110   a . Temperature sensor  410 , by way of non-limiting example, is one or more of a thermocouple, resistive temperature device (RTD), thermistor, and integrated silicon-based sensor. Integrated silicon-based sensors may integrate a temperature sensor and signal-conditioning circuitry in a single chip/device. Other temperature sensing technologies may be used, for example, infrared (e.g., pyrometer) and thermal pile. In some embodiments, temperature sensor  410  is an analog temperature sensor that converts temperature to an analog voltage, such as a Microchip Technology Inc. MCP9700A. 
         [0036]    Differential amplifier  420  determines V DS . For example, differential amplifier  420  is electrically coupled to drain  114   a  and source  118   a  of MOSFET  110   a . Differential amplifier  420 , by way of non-limiting example, is one or more of a current shunt monitor (CSM), operational amplifier (op-amp), difference amplifier (DA), instrumentation amplifier (IA), and the like. In some embodiments, differential amplifier  420  is an LM344 op-amp (e.g., operating in differential mode). By way of non-limiting example, differential amplifier  420  is at least one of a Texas Instruments LMV341, LMV342, and LMV344. 
         [0037]    Processor  430  determines I LOAD  using signals from temperature sensor  410  and differential amplifier  420 . For example, signals from temperature sensor  410  and/or differential amplifier  420  are digital signals representing values for temperature and/or voltage, respectively. Alternatively or additionally, signals from temperature sensor  410  and/or differential amplifier  420  are analog signals including values for temperature and/or voltage, respectively. 
         [0038]    Processor  430  may integrate one or more analog-to-digital converters (ADCs; not shown in  FIG. 4 ). ADCs convert a continuous physical quantity (e.g., voltage) to a digital number that represents the quantity&#39;s amplitude. Alternatively or additionally, one or more ADCs may be external to processor  430  and be disposed in at least one signal path between processor  430  and at least one of temperature sensor  410  and differential amplifier  420 . 
         [0039]    In some embodiments, processor  430  is an embedded processor disposed on or in power apparatus  130 . For example, processor  430  is an ARM processor, such as a Freescale Kinetis microcontroller (e.g., KL95Z32, KL25Z32, etc.). ARM is a family of instruction set architectures for computer processors based on a reduced instruction set computing (RISC) architecture developed by British company ARM Holdings. By way of further non-limiting example, processor  430  is an embedded processor having at least one of: on-chip RAM, on-chip non-volatile memory, on-chip ADC, on-chip digital-to-analog converter (DAC), and the like. In various embodiments, processor  430  is at least one of: a mobile, desktop, and cloud-based computing system communicatively coupled to power apparatus  130 . For example, processor  430  is communicatively coupled to power apparatus  130  through wired and/or wireless networks. Processor  430  and networks are described further in relation to  FIG. 8 . 
         [0040]    The R DS  of MOSFET  110   a  may be determined (e.g., by processor  430 ) using a temperature measured by temperature sensor  410 . For example, a mathematical relationship between a measured temperature and R DS  is represented by an empirically derived (e.g., from simulations and/or bench measurements such as reflected in  FIGS. 3B and 3C ) second-order polynomial. 
         [0041]    By way of non-limiting example, the second-order polynomial is: 
         [0000]        R   DS =6.46229×10 −9  (Temp) 2 +2.44568×10 −6  (Temp)+0.000588037  (1)
 
         [0000]    where Temp is the temperature. For example, Equation 1 may be derived using a (simulation) circuit shown in  FIG. 3D  to apply a constant load of 10 Amps (other loads may be used) over a discrete range temperatures from 20° C.-100° C. (other temperature ranges may be used) to determine corresponding V DS  values. R DS  values are calculated using the determined V DS  values: 
         [0000]        R   DS   =V   DS /10 Amps  (2)
 
         [0000]    The calculated R DS  values and associated temperature values may be represented by a data plot (of R DS  and temperature). A best-fit second-order polynomial for the data plot is determined (e.g., using Mathcad from Parametric Technology Corporation, Excel from Microsoft Corporation, etc.). Multiple measurements at various known temperatures can be taken to empirically determine one or more R DS -temperature curves from which one or more best-fit lines may be computed. Once Equation 1 is determined using empirical data, Equation 1 can be used to calculate R DS  as a function of temperature (e.g., using temperature sensor  410 ). 
         [0042]    Once R DS  is computed using a temperature (e.g., temperature measured by temperature sensor  410 ) and the best-fit second-order polynomial (e.g., Equation 1), I LOAD  (e.g., current provided to load  120  by power apparatus  130 ) is calculated: 
         [0000]        I   LOAD   =V   DS   /R   DS   (3)
 
         [0043]      FIG. 5  illustrates system  500  for temperature-compensated current monitoring according to various embodiments. As shown in  FIG. 5 , differential amplifier U 6  is a single-ended non-inverting amplifier referenced to the floating source voltage of MOSFETs M 1  (and M 2 ). When MOSFETs M 1  (and M 2 ) are in the off state, the voltage difference on the inputs of op-amp U 6  can be as high as an input voltage (e.g., voltage seen at drain  114   a ), VIN (e.g., 28 Volts). Since op-amp inputs generally cannot withstand a voltage substantially above its power supply input (e.g., V CC ), zener diode D 3  provides protection. Current limiting resistor R 11  can be any value suitable for cancelling op-amp current offset. 
         [0044]    By way of non-limiting example, op-amp U 6  has a fixed gain of 5× to improve ADC resolution and allow for an increase in R DS  that will (at maximum) double the measured voltage. Other gains may be used. In some embodiments, input voltage offset is not trimmed out in hardware but trimmed out in a calibration process as a software offset removal. 
         [0045]    Single-ended non-inverting op-amp U 6  offers advantages over a differential op-amp when, for example, microcontroller  430  has built in DAC and ADC functions to both read the current and provide a reference voltage for a high-speed comparator (e.g., for handling instant trip protection). In some embodiments where microcontroller  430  does not include DAC and ADC functions, a differential op-amp (e.g.,  FIG. 4 ) may be used. 
         [0046]      FIG. 6  depicts module  600  of power apparatus  130  ( FIGS. 1-4 ). Module  600  includes two power MOSFETs  110   a   1  and  110   a   2 , temperature sensor  410  disposed between MOSFETs  110   a   1  and  110   a   2 , and substrate  610 . Module  600  includes connectors  630  for physical and electrical connection with other components of power apparatus  130  (not shown in  FIG. 6 ). 
         [0047]    In some embodiments, Substrate  610  is a printed circuit board (PCB) comprising one or more metal and dielectric layers. For example, the metal layer is copper and the dielectric layer is at least one of: polytetrafluoroethylene (e.g., Teflon), FR-2 (e.g., phenolic cotton paper), FR-3 (e.g., cotton paper and epoxy), FR-4 (e.g., woven glass and epoxy), FR-5 (e.g., woven glass and epoxy), FR-6 (e.g., matte glass and polyester), G-10 (e.g., woven glass and epoxy), CEM-1 (e.g., cotton paper and epoxy), CEM-2 (e.g., cotton paper and epoxy), CEM-3 (e.g., non-woven glass and epoxy), CEM-4 (e.g., woven glass and epoxy), CEM-5 (e.g., woven glass and polyester), and the like. Connectors  630  may be comprised of at least one of: one or more metal and dielectric layers of substrate  610 , metal leads, and an electrical connector. 
         [0048]    In some embodiments, heat sink  620  may be mechanically and/or thermally coupled to power MOSFETs  110   a   1  and  110   a   2 . For example, heat sink  620  is disposed over a top surface of power MOSFETs  110   a   1  and  110   a   2 . The heat sink may be mechanically and thermally coupled to power MOSFETs  110   a   1  and  110   a   2  using one or more of clips, pins, springs, standoffs, thermal tape, epoxy, thermal grease, and the like. Heat sinks are passive heat exchangers that cool power MOSFETs  110   a   1  and  110   a   2  by dissipating heat into the surrounding medium. By way of non-limiting example, heat sink  620  is comprised of at least one of: copper and aluminum alloy. In some embodiments, temperature sensor  410  is thermally coupled to heat sink  620 . By way of further non-limiting example, temperature sensor  410  is disposed on or under heat sink  620  and in-between power MOSFETs  110   a   1  and  110   a   2 . 
         [0049]    Other combinations and permutations may be used in accordance with various embodiments. For example, any number of power MOSFET  110   a  is included in module  600  (e.g., a single power MOSFET or an array of power MOSFETS); any number of temperature sensor  410  is included in module  600 ; each of temperature sensor  410  measures temperature for one power MOSFET  110   a  or more than one power MOSFET  110   a ; any number of heat sink  620  is included in module  600 ; each heat sink  620  is thermally coupled to one power MOSFET or more than one power MOSFET  110   a ; and temperature sensor  410  is disposed on, in, under, or proximate to at least one heat sink  620  and/or proximate to at least one power MOSFET(s)  110   a.    
         [0050]      FIG. 7  illustrates a method  700  for temperature-compensated current monitoring according to some embodiments. In various embodiments, at least some of steps  710 - 770  are performed by processor  430  ( FIG. 4 ). 
         [0051]    At Step  710 , a pre-determined current limit I LIMIT  is received. For example, I LIMIT  is an upper threshold at and/or above which load  120  ( FIGS. 1-4 ) has a condition (marginal condition/poor health, impending failure, and the like). Other current limits may be used, for example, I LIMIT  is a lower threshold at and/or below which load  120  has condition, or I LIMIT1  is an upper threshold at and/or above which load  120  has a first condition and I LIMIT2  is a lower threshold at and/or below which load  120  has a second condition. 
         [0052]    At Step  720 , a temperature is received. For example, a temperature is an output from temperature sensor  410  ( FIGS. 4 and 5 ) processed by an ADC. In some embodiments, the received temperature is the temperature of one or more power MOSFETs  110   a.    
         [0053]    At Step  730 , resistance R DS  is computed. In some embodiments, R DS  is computed using the received temperature and a second order polynomial equation (e.g., Equation 1). 
         [0054]    At Step  740 , voltage V DS  is received. For example, V DS  is an output from differential amplifier  420  ( FIG. 4 ) and/or op-amp U 6  ( FIG. 5 ) processed by an ADC. 
         [0055]    At Step  750 , current LOAD is calculated. In some embodiments, LOAD is calculated using the computed R DS , the received V DS , and Ohm&#39;s Law (e.g., Equation 3). 
         [0056]    At Step  760 , I LOAD  is compared to I LIMIT . In some embodiments, whether I LOAD  is equal to and/or greater than I LIMIT  is determined. Other comparisons may be used, for example, whether I LOAD  is equal to and/or greater than I LIMIT , or whether I LOAD  is equal to and/or greater than I LIMIT1  and whether LOAD is equal to and/or less than I LIMIT2 . When the comparison condition(s) is not satisfied, method  700  may continue to Step  710  or  720 . When the comparison condition(s) is satisfied, method  700  may continue to Step  770 . 
         [0057]    At Step  770 , power MOSFET  110   a  is switched to an off state (and current removed from load  120 ) and/or a notification is provided to a user. For example, source  116   a  is used to turn switch  110   a  to an off state, at least cutting electrical power to load  120 . In some embodiments, the provided notification directs a user to service (e.g., perform preventative maintenance on) load  120 . By way of non-limiting example, servicing includes at least one of: inspecting load  120 , performing diagnostic tests on load  120 , and replacing load  120  with a serviceable unit, averting unscheduled and/or catastrophic interruptions in the operation of system  100 ,  200 ,  300 , and/or  400  ( FIGS. 1-4 ). In some embodiments, the notification is provided through at least one of a light-emitting diode (LED) on or about power apparatus  130 , a power monitoring panel of power apparatus  130  ( FIGS. 1-4 ), in an email, in an SMS message, in a pre-recorded audio message played during an automated telephone call to the user, in an audible alarm of power apparatus  130 , and the like. 
         [0058]    Various embodiments of the present invention offer one or more of the advantages of higher accuracy for current monitoring, reduced wasted electrical power, and decreased generated heat. In some embodiments, the calculated I LOAD —when there is a 10° C. difference between the temperature from temperature sensor  410  ( FIG. 4 ) and a junction temperature of power MOSFET  110   a  ( FIGS. 3 and 4 )—is still within 0.8% of an actual I LOAD . 
         [0059]      FIG. 8  illustrates an exemplary computer system  800  that may be used to implement some embodiments of the present invention. The computer system  800  in  FIG. 8  may be implemented in the contexts of the likes of computing systems, networks, servers, or combinations thereof. The computer system  800  in  FIG. 8  includes one or more processor units  810  and main memory  820 . Main memory  820  stores, in part, instructions and data for execution by processor units  810 . Main memory  820  stores the executable code when in operation, in this example. The computer system  800  in  FIG. 8  further includes a mass data storage  830 , portable storage device  840 , output devices  850 , user input devices  860 , a graphics display system  870 , and peripheral devices  880 . 
         [0060]    The components shown in  FIG. 8  are depicted as being connected via a single bus  890 . The components may be connected through one or more data transport means. Processor unit  810  and main memory  820  is connected via a local microprocessor bus, and the mass data storage  830 , peripheral device(s)  880 , portable storage device  840 , and graphics display system  870  are connected via one or more input/output (I/O) buses. 
         [0061]    Mass data storage  830 , which can be implemented with a magnetic disk drive, solid state drive, or an optical disk drive, is a non-volatile storage device for storing data and instructions for use by processor unit  810 . Mass data storage  830  stores the system software for implementing embodiments of the present disclosure for purposes of loading that software into main memory  820 . 
         [0062]    Portable storage device  840  operates in conjunction with a portable non-volatile storage medium, such as a flash drive, floppy disk, compact disk, digital video disc, or Universal Serial Bus (USB) storage device, to input and output data and code to and from the computer system  800  in  FIG. 8 . The system software for implementing embodiments of the present disclosure is stored on such a portable medium and input to the computer system  800  via the portable storage device  840 . 
         [0063]    User input devices  860  can provide a portion of a user interface. User input devices  860  may include one or more microphones, an alphanumeric keypad, such as a keyboard, for inputting alphanumeric and other information, or a pointing device, such as a mouse, a trackball, stylus, or cursor direction keys. User input devices  860  can also include a touchscreen. Additionally, the computer system  800  as shown in  FIG. 8  includes output devices  850 . Suitable output devices  850  include speakers, printers, network interfaces, and monitors. 
         [0064]    Graphics display system  870  include a liquid crystal display (LCD) or other suitable display device. Graphics display system  870  is configurable to receive textual and graphical information and processes the information for output to the display device. 
         [0065]    Peripheral devices  880  may include any type of computer support device to add additional functionality to the computer system. 
         [0066]    The components provided in the computer system  800  in  FIG. 8  are those typically found in computer systems that may be suitable for use with embodiments of the present disclosure and are intended to represent a broad category of such computer components that are well known in the art. Thus, the computer system  800  in  FIG. 8  can be a personal computer (PC), hand held computer system, telephone, mobile computer system, workstation, tablet, phablet, mobile phone, server, minicomputer, mainframe computer, wearable, or any other computer system. The computer may also include different bus configurations, networked platforms, multi-processor platforms, and the like. Various operating systems may be used including UNIX, LINUX, WINDOWS, MAC OS, PALM OS, QNX ANDROID, IOS, CHROME, and other suitable operating systems. 
         [0067]    Some of the above-described functions may be composed of instructions that are stored on storage media (e.g., computer-readable medium). The instructions may be retrieved and executed by the processor. Some examples of storage media are memory devices, tapes, disks, and the like. The instructions are operational when executed by the processor to direct the processor to operate in accord with the technology. Those skilled in the art are familiar with instructions, processor(s), and storage media. 
         [0068]    In some embodiments, the computing system  800  may be implemented as a cloud-based computing environment, such as a virtual machine operating within a computing cloud. In other embodiments, the computing system  800  may itself include a cloud-based computing environment, where the functionalities of the computing system  800  are executed in a distributed fashion. Thus, the computing system  800 , when configured as a computing cloud, may include pluralities of computing devices in various forms, as will be described in greater detail below. 
         [0069]    In general, a cloud-based computing environment is a resource that typically combines the computational power of a large grouping of processors (such as within web servers) and/or that combines the storage capacity of a large grouping of computer memories or storage devices. Systems that provide cloud-based resources may be utilized exclusively by their owners or such systems may be accessible to outside users who deploy applications within the computing infrastructure to obtain the benefit of large computational or storage resources. 
         [0070]    The cloud is formed, for example, by a network of web servers that comprise a plurality of computing devices, such as the computing system  800 , with each server (or at least a plurality thereof) providing processor and/or storage resources. These servers manage workloads provided by multiple users (e.g., cloud resource customers or other users). Typically, each user places workload demands upon the cloud that vary in real-time, sometimes dramatically. The nature and extent of these variations typically depends on the type of business associated with the user. 
         [0071]    It is noteworthy that any hardware platform suitable for performing the processing described herein is suitable for use with the technology. The terms “computer-readable storage medium” and “computer-readable storage media” as used herein refer to any medium or media that participate in providing instructions to a CPU for execution. Such media can take many forms, including, but not limited to, non-volatile media, volatile media and transmission media. Non-volatile media include, for example, optical, magnetic, and solid-state disks, such as a fixed disk. Volatile media include dynamic memory, such as system RAM. Transmission media include coaxial cables, copper wire and fiber optics, among others, including the wires that comprise one embodiment of a bus. Transmission media can also take the form of acoustic or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, a hard disk, magnetic tape, any other magnetic medium, a CD-ROM disk, digital video disk (DVD), any other optical medium, any other physical medium with patterns of marks or holes, a RAM, a PROM, an EPROM, an EEPROM, a FLASH memory, any other memory chip or data exchange adapter, a carrier wave, or any other medium from which a computer can read. 
         [0072]    Various forms of computer-readable media may be involved in carrying one or more sequences of one or more instructions to a CPU for execution. A bus carries the data to system RAM, from which a CPU retrieves and executes the instructions. The instructions received by system RAM can optionally be stored on a fixed disk either before or after execution by a CPU. 
         [0073]    Computer program code for carrying out operations for aspects of the present technology may be written in any combination of one or more programming languages, including an object oriented programming language such as JAVA, SMALLTALK, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). 
         [0074]    The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present technology has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. Exemplary embodiments were chosen and described in order to best explain the principles of the present technology and its practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. 
         [0075]    Aspects of the present technology are described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0076]    These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. 
         [0077]    The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0078]    The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present technology. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions. 
         [0079]    While the present technology has been described in connection with a series of preferred embodiment, these descriptions are not intended to limit the scope of the technology to the particular forms set forth herein. It will be further understood that the methods of the technology are not necessarily limited to the discrete steps or the order of the steps described. To the contrary, the present descriptions are intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the technology as defined by the appended claims and otherwise appreciated by one of ordinary skill in the art.