Electric power measurement

An information processing device, a method and computer program product are disclosed. The information processing device includes a component, a resistance unit, and a measurement unit that measures a voltage drop of the resistance unit, wherein the resistance unit is connected on an electric power line. The method includes providing electric power to a component, adjusting a resistance unit based on an operating state of a control unit, and measuring a voltage drop of the resistance unit with a measurement unit. The computer program product includes executable code to perform providing electric power to a component; adjusting a resistance unit based on an operating state of a control unit, and measuring a voltage drop of the resistance unit with a measurement unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to Japan Patent Application No. 2018-164833 filed on Sep. 3, 2018 for Toshinari Sumikawa et al., the entire contents of which are incorporated herein by reference for all purposes.

FIELD

The present invention relates to an information processing device, a control method, and a computer program product.

BACKGROUND

Some information processing devices and methods include a measurement instrument that measures power consumption of a component of the information processing device. Sometimes, this is performed by measuring a voltage drop across a resistor with a known resistance that is provided on an electric power line for supplying electric power to a component. However, the component may be damaged, or the accuracy of measurement may be reduced.

BRIEF SUMMARY

An information processing device comprises a component, a resistance unit having a variable resistance value, and a measurement unit that measures a voltage drop of the resistance unit, wherein the resistance unit is connected on an electric power line for supplying electrical power to the component.

A control method for an information processing device comprises providing electric power to a component via an electric power line, adjusting a resistance unit located on the electric power line that has a variable resistance value based on an operating state of a control unit that controls operation of the information processing device, and measuring a voltage drop of the resistance unit with a measurement unit.

A computer program product comprises a non-transitory computer readable storage medium that stores code executable by a processor, the executable code comprising code to providing electric power to a component via an electric power line; adjusting a resistance unit located on the electric power line that has a variable resistance value based on an operating state of a control unit that controls operation of the information processing device, and measuring a voltage drop of the resistance unit with a measurement unit.

DETAILED DESCRIPTION

To measure electrical power usage, it is desirable that the resistance value of the detection resistor is small when the component is operating. The larger the resistance value of the detection resistor is, the higher the voltage drop that is generated across the detection resistor, and the voltage that is provided to the component becomes relatively lower. This may harm the operation of the component. In order to avoid a negative impact on the operation of the component, it is desired to make the voltage drop in the detection resistor sufficiently smaller than that in the component (for example, less than 10% of the voltage drop in the component). On the other hand, it is desirable that the resistance value of the detection resistor is large when the operating state of the component is a sleep state. This is so because when the resistance value of the detection resistor is small, the voltage drop that is generated in the detection resistor is also small and measurement error tends to become larger. In order to detect the voltage drop or power consumption in the component with sufficient accuracy, it is desirable to make the voltage drop of the detection resistor larger than a predetermined reference value (for example, 1.0 mV). The present subject matter solves the above-described problem, and can reduce a measurement error in a voltage drop without affecting the operation of the component by setting a resistance value corresponding to the operating state of the component.

The first exemplary embodiment of the present invention will be described with reference to the drawings. In the following description, the case where an information processing device1is mainly a Laptop PC will be considered. However, the information processing device1is not limited to a Laptop PC, but may be realized in any form, such as a desktop PC, a tablet terminal device, or a smart hone.

FIG. 1is a schematic block diagram illustrating a hardware configuration example of the information processing device1according to an embodiment of the present invention.

The information processing device1includes system devices and peripheral devices. The system devices of the information processing device1include a Central Processing Unit (CPU)151, a Graphics Processing Unit (GPU)153, a system memory155, and an Input Output (I/O) controller163. The system memory155and the I/O controller163are connected to the CPU151. A display165and the I/O controller163are connected to the GPU153. The CPU151, the GPU153, an audio device157, a communication module159, a Solid State Drive (SSD)161, and an Embedded Controller (EC)171are connected to the I/O controller163.

The audio device157includes one or both of a speaker and a microphone, for example. The communication module159communicatively connects to other devices. The communication module159is, for example, a wireless module that connects to other devices using a predetermined wireless communication system.

The SSD161stores various data. The SSD161stores data that is used for the operation of the system device and data that is acquired by the operation of the system device. The data that is stored in the SSD161can be erased and updated.

The EC171is a microcomputer that includes a processor, a storage medium, and a programmable logic circuit. This processor may be a CPU that is different from the CPU151, for example. The storage medium may be a Read Only Memory (ROM) or a Random Access Memory (RAM) is included, for example. The EC171operates independently of the CPU151and mainly controls the inside of the information processing device1or a surrounding operating environment.

The processor of the EC171reads a control program previously stored in the ROM and performs processing that is instructed by various instructions described in the read control program to perform a part or all of functions of each unit that will be described later. In the present embodiment, performing processing that is instructed by instructions described in various programs may be referred to as “executing the program,” but it is not limited to being performed by the EC171. In addition, starting the execution may be referred to as “activation.”

An input device177, a signal line of a Direct Current/Direct Current (DC/DC) converter189, and a signal line of a power supply unit191are connected to the EC171. The DC/DC converter189operates under control of the EC171, converts a voltage of electric power that is supplied from the power supply unit191, and supplies electric power of a specified voltage to each component that forms the information processing device1. The DC/DC converter189supplies electric power to each device in response to an instruction of a power control signal that is input from the EC171. For example, when it is detected that an operation switch (not shown) provided in the information processing device1is held down, the EC171determines that the information processing device1should be started and outputs power control signals indicating supply of electric power to each device, to the DC/DC converter189.

In addition, event information may be input from the CPU151to the EC171via the I/O controller163. When the input event information indicates a transition from a standard mode to a sleep mode as an operation mode of the system of the information processing device1, the EC171outputs a power control to the DC/DC converter189signal indicating a decrease in a power supply amount to a predetermined component. When the power control signal is received from the EC171, the DC/DC converter189decreases the power supply amount to the component. The decrease in the power supply amount lowers the level of activity in the operating state of the component. The EC171may stop power supply to some components, for example, the display165and the audio device157. Note that examples of operation modes will be described later.

On the other hand, when event information indicating a transition from the sleep mode to the standard mode is input from the CPU151, the EC171outputs a power control signal to the DC/DC converter189indicating an increase in a power supply amount to a predetermined component. When the power control signal is sent from the EC171, the DC/DC converter189increases the power supply amount to the predetermined component. The increase in the power supply amount raises the level of activity in the operating state of the component. The EC171may resume the supply of electric power to the component to which the supply of electric power was cut off in the sleep mode.

The power supply unit191supplies electric power to the DC/DC converter189. The power supply unit191includes an Alternating Current/Direct Current (AC/DC) adaptor, a battery, and a battery charger (not shown). The AC/DC adaptor converts alternating-current power that is supplied from a commercial power supply into direct-current power. The AC/DC adaptor supplies the converted direct-current power to the DC/DC converter189and the battery charger. The battery charger controls charging of electric power that is supplied from the AC/DC adaptor in the battery under the control of the EC171. The battery charger charges the battery with the remaining electric power of the supplied electric power. The battery accumulates the electric power that is supplied from the battery charger. The battery may be a lithium-ion battery, for example. When no electric power is supplied from the AC/DC adaptor or the electric power to be supplied to the information processing device1is insufficient, the battery discharges the accumulated electric power and supplies it to the DC/DC converter189. The power supply unit191may be fixed in the chassis of the information processing device1or may include a mechanism that is attachable to and detachable from the chassis of the information processing device1.

The CPU151consumes electric power that is supplied from the DC/DC converter189. The CPU151typically has variable processing power, and the higher the processing power is, the greater the power consumption is. As a measure of the processing power, an operating frequency or a usage rate, etc., is used.

The CPU151runs an Operating System (OS) and other programs. The CPU151may make an operation mode changeable depending on a processing state up to that point and take any one of a plurality of operation modes. Typically, power consumption differs from operation mode to operation mode in accordance with the processing power. The operation mode that may be used by the CPU151may include a standard mode and a sleep mode, for example. The standard mode is a standard operation mode that processes common tasks using a predetermined standard processing power. The common tasks include processing that is instructed directly or indirectly by the OS and processing that is instructed directly or indirectly by software, the start-up of which is instructed by user's operation or user-optional setting.

The sleep mode is an operation mode in which power consumption is lower than in the standard mode. Since the sleep mode is an operation mode in which processing power is lower than in the standard mode, it is also referred to as an idle mode. In the present embodiment, the sleep mode does not necessarily involve a complete stop of the operation of the CPU151. Since user operations are not typically performed in the sleep mode, operation of the component in response to the user's operation is not expected. A condition for the transition from the standard mode to the sleep mode may be, for example, a state where input of an operation signal from the input device177is not detected continues for a predetermined time (for example, 3 to 5 minutes) or more. A condition for the transition from the sleep mode to the standard mode may be, for example, the input of an operation signal from the input device177is detected.

Measurement System

Next, a measurement system2that measures power consumption of each component of the information processing device1will be described.FIG. 2is a schematic block diagram illustrating a configuration example of the measurement system2according to the present embodiment. The measurement system2includes a power supply unit12, a resistance unit20, a component40, and the CPU151.

The power supply unit12supplies electric power required for operation to the component40. The above-described DC/DC converter189corresponds to the power supply unit12. The resistance unit20is installed on an electric power line for supplying electric power from the power supply unit12to the component40. The electric power line is also referred to as a bus. Electrical resistance of the resistance unit20is variable as described later.

A measurement unit30is connected to the resistance unit20in parallel and measures a voltage drop that is generated across the resistance unit20in response to current flowing through the electric power line. The voltage drop is also referred to as a potential difference. The measurement unit30can calculate a current value of the current flowing through the electric power line from the measured voltage drop and a resistance value of the resistance unit20. The measurement unit30can calculate the power consumption of the component40by multiplying the voltage drop by the current value. The measurement unit30outputs measurement information indicating any of the measured voltage drop, the calculated current value, and the power consumption, or any combination thereof, to the CPU151. The measurement unit30may be formed as a chipset. For example, an Energy Estimation Engine (E3) can be used as the measurement unit30.

The component40is a component that forms part of the information processing device1, the voltage drop of which is to be measured. For example, any of the audio device157, the communication module159, and the SSD161, or any combination thereof may correspond to the component40. Operation of these members is controlled by the CPU151. The component40may include another member, for example, any of the CPU151, the GPU153, the system memory155, and the display165, or any combination thereof.

Note that when the operation mode is the standard mode, the component40is likely to operate in a standard operating state. On the contrary, when the operation mode is the sleep mode, the component40is expected to not operate at all, or is expected to operate in an operating state in which the level of activity is lower than in the standard operating state. Thus, the CPU151controls the resistance value of the resistance unit20in accordance with the operation mode. In other words, the resistance unit20sets a resistance value in accordance with the operation mode.

In one example, the CPU151outputs to the resistance unit20an SLP_S0# as a control signal indicating the operation mode at that time. The SLP_S0# is an electrical signal indicating whether or not the operation mode is a sleep mode in an S0 state defined by an Advanced Configuration and Power Interface (ACPI). The S0 state indicates a state where the CPU151operates. The SLP_S0# has any of a high voltage value (H) and a low voltage value (L) as a voltage value. The high voltage value is a positive voltage value that is significantly higher than 0V and indicates the standard mode. The low voltage value is a positive voltage value that is sufficiently closer to 0V than the high voltage value and indicates the sleep mode.

Next, a configuration example of the resistance unit20will be described.

The resistance unit20includes a voltage regulator22, switch units24-1,24-2,28-1, and28-2, and resistors26-1and26-2. The voltage regulator22has one end that is connected to the CPU151and the other end that is connected to base electrodes of the switch units24-2and28-2. The voltage regulator22regulates a voltage of a control signal that is supplied from the CPU151via its one end, and applies the control signal with the voltage regulated from its another end to each base electrode of the switch units24-2and28-2. The regulated voltage for a high voltage value will be, for example, a negative voltage value that is lower than 0V. The regulated voltage for a low voltage value will be, for example, a positive voltage value that is significantly higher than 0V.

The resistors26-1and26-2have resistance values R1and R2, respectively. In the example shown inFIG. 2, the resistance value R1is much smaller than the resistance value R2.

An NPN type transistor is used for each of the switch units24-1,24-2,28-1, and28-2. The NPN type transistor typically has a base electrode, a collector electrode, and an emitter electrode. The NPN type transistor conducts current from the collector electrode to the emitter electrode when a positive voltage that is significantly higher than 0V (hereinafter referred to as a positive voltage) is applied to the base electrode, and blocks the current from the collector electrode to the emitter electrode when another voltage (hereinafter referred to as a non-positive voltage) is applied. The switch units24-1,24-2,28-1, and28-2are connected so that when the positive voltage is applied to each base electrode thereof, the current that is supplied from the power supply unit12passes via each collector electrode and emitter electrode. Then, when a positive voltage is applied to the base electrodes of the switch units24-1and28-1, a non-positive voltage is applied to each base electrode of the switch units24-2and28-2, and thus the current from the power supply unit12does not pass through the resistor26-2but passes through the resistor26-1to be supplied to the component40. On the other hand, when a positive voltage is applied to the base electrodes of the switch units24-2and28-2, a non-positive voltage is applied to the base electrodes of the switch units24-1and28-1, and thus the current flowing from the power supply unit12through the electric power line does not pass through the resistor26-1but passes through the resistor26-2to be supplied to the component40.

Therefore, the base electrode of the switch unit24-1is connected to the CPU151, the collector electrode thereof is connected to the power supply unit12, and the emitter electrode thereof is connected to one end of the resistor26-1and a first input end I1of the measurement unit30, respectively.

The base electrode of the switch unit24-2is connected to one end of the voltage regulator22, the collector electrode thereof is connected to the power supply unit12, and the emitter electrode thereof is connected to one end of the resistor26-2and a second input end12of the measurement unit30, respectively.

The base electrode of the switch unit28-1is connected to the CPU151, the collector electrode thereof is connected to the other end of the resistor26-1and a first output end O1of the measurement unit30, and the emitter electrode thereof is connected to the component40, respectively.

The base electrode of the switch unit28-2is connected to the CPU151, the collector electrode thereof is connected to the other end of the resistor26-2and a second output end O2of the measurement unit30, and the emitter electrode thereof is connected to the component40, respectively.

That is, the electric power line for supplying electric power from the power supply unit12to the component40is branched into a first route and a second route. The first route is a route that passes through the collector electrode of the switch unit24-1, the emitter electrode of the switch unit24-1, the one end of the resistor26-1, the other end of the resistor26-1, the collector electrode of the switch unit28-1, and the emitter electrode of the switch unit28-1. The second route is a route that passes through the collector electrode of the switch unit24-2, the emitter electrode of the switch unit24-2, the one end of the resistor26-2, the other end of the resistor26-2, the collector electrode of the switch unit28-2, and the emitter electrode of the switch unit28-2. Then, either the first route or the second route is properly used as a route for the current from the power supply unit12to flow, depending on whether the operation mode is the standard mode or not.

The measurement unit30includes a first measurement channel that measures a first voltage drop V1between the first input end I1and the first output end O1and a second measurement channel that measures a second voltage drop V2between the second input end12and the second output end O2. Since the first measurement channel and the second measurement channel are in parallel with the resistor26-1and the resistor26-2, respectively, they can measure the voltage drops in the resistors26-1and26-2, respectively.

Therefore, when the operation mode of the CPU151is the standard mode, the current from the power supply unit12is supplied to the component40via the switch unit24-1, the resistor26-1, and the switch unit28-1. At this time, the measurement unit30can measure the voltage drop that is generated across the resistor26-1as a first voltage drop when the current flows via the resistor26-1.

When the operation mode of the CPU151is the sleep mode, the current from the power supply unit12is supplied to the component40via the switch unit24-2, the resistor26-2, and the switch unit28-2. At this time, the measurement unit30can measure the voltage drop that is generated across both ends of the resistor26-2as a second voltage drop when the current flows via the resistor26-2.

Then, when the operation mode of the CPU151is the standard mode or the sleep mode, the operating state of the component40is expected to be in operation (active) or out of service (sleep), respectively. Thus, it is possible to resolve an operation failure due to a change in the voltage drop that is generated in the resistance unit20when the component40is in operation and the reduction in measurement accuracy due to the voltage drop that is generated in the resistance unit20being small when the component40is out of service.

Note that the measurement unit30may specify a measurement channel corresponding to the operation mode that is indicated by the control signal input from the CPU151. When the standard mode is indicated by the control signal, the measurement unit30selects the second measurement channel. When the sleep mode is indicated by the control signal, the measurement unit30selects the first measurement channel. The measurement unit30measures a voltage drop with the selected measurement channel and outputs measurement information indicating the measured voltage drop to the CPU151. The measurement information may include either or both of the currents that are calculated from the measured voltage drop and the power consumption that is calculated from the current and voltage drop.

Measurement Example

Next, an example of measurement of the voltage drop that is generated in the resistance unit20will be described usingFIG. 3. In this example, the resistance values R1and R2that the resistance unit20can have are 1.0[Ω] and 0.01[Ω], respectively, the voltage of the power supply unit12is 3.3[V], and when the operating state of the component40is active and sleep, the power consumption is 1.0[W] and 3 [mW], respectively.

FIG. 3Aillustrates the case where the resistance value of the resistance unit20is R1, and the operating state of the component is active. In this example, the current flowing through the resistance unit20is 0.3[A] (≈1.0/3.3). Thus, the voltage drop that is generated across both ends of the resistance unit20is 0.3[V] (≈0.3×1.0). In light of the fact that the voltage drop by the component40is 3.3[V] (≈1.0/0.3), the voltage drop that is generated across both ends of the resistance unit20can affect the operation of the component40.

FIG. 3Billustrates the case where the resistance value of the resistance unit20is R1, and the operating state of the component is sleep. In this example, the current flowing through the resistance unit20is 0.9 [mA] (≈3/3.3). Thus, the voltage drop that is generated across both ends of the resistance unit20is 0.9 [mV] (≈0.9×1.0) and negligibly small compared to the voltage drop by the component40.

FIG. 3Cillustrates the case where the resistance value of the resistance unit20is R2, and the operating state of the component is active. In this example, the current flowing through the resistance unit20is 0.3[A] (≈1.0/3.3). Thus, the voltage drop that is generated across both ends of the resistance unit20is 3.0 [mV] (≈0.3×0.01×1000). In light of the fact that the voltage drop by the component40is about 3.3[V] (=1.0/0.3), the voltage drop that is generated across both ends of the resistance unit20is negligibly small compared to the voltage drop by the component40.

FIG. 3Dillustrates the case where the resistance value of the resistance unit20is R2, and the operating state of the component40is sleep. In this example, the current flowing through the resistance unit20is 0.9 [mA] (≈3/3.3). Thus, the voltage drop that is generated across both ends of the resistance unit20is 9[μV] (≈0.9×0.01×1000), and thus the accuracy degrades. A measurement error in the voltage drop typically tends to become significant as the voltage drop becomes smaller. For example, when the voltage drop is 1 mV, the measurement error is about 1%.

As described above, in the information processing device1according to the present embodiment, when the operating state of the component40changes to the active state, the resistance value of the resistance unit20switches to R2(FIG. 3C). When the operating state of the component40changes to the sleep state, the resistance value of the resistance unit20switches to R1(FIG. 3B). Thus, a sufficiently large voltage drop that may affect the operation of the component40(FIG. 3A) is avoided. Additionally, a sufficiently small voltage drop that makes the measurement error significant (FIG. 3D) is also avoided.

Second Embodiment

The second embodiment of the present invention and mainly differences from the first embodiment will be described usingFIG. 4. Elements that are common to those of the first embodiment are followed by common symbols and the description thereof is quoted.

The information processing device1according to the present embodiment includes a measurement system2a(FIG. 4) in place of the measurement system2(FIG. 2). The measurement system2aincludes a resistance unit20ain place of the resistance unit20(FIG. 2).

In addition to the first route and the second route described above, a third route is further provided in the resistance unit20a. The third route is a route that runs via a switch unit24-tand a switch unit28-t. No resistor is provided on the third route. The CPU151controls whether or not to pass the current from the power supply unit12through the third route. This control controls whether or not to short-circuit between the power supply unit12and the component40. Then, in short-circuiting between the power supply unit12and the component40, the CPU151does not pass the current through but blocks the first route and the second route.

Unlike the resistance unit20, the resistance unit20afurther includes an inverter23, and switch units24-tand28-t. The inverter23has one end that is connected to the CPU151and the other end that is connected to each base electrode of the switch units24-tand28-t. The inverter23inverts a polarity of a measurement control signal that is input from its one end and applies the measurement control signal whose polarity is inverted to each base electrode of the switch units24-tand28-t.

The switch units24-tand28-tinclude an NPN type transistor. In this example, the third route runs via the collector electrode of the switch unit24-t, the emitter electrode of the switch unit24-t, the collector electrode of the switch unit28-t, and the emitter electrode of the switch unit28-t.

The measurement control signal whose polarity is inverted is applied to the base electrodes of the switch units24-tand28-t. The measurement control signal has, for example, any of a positive voltage value that is significantly higher than 0V and a negative voltage value that is significantly lower than 0V, as a voltage value. At the stage of being output from the CPU151, the positive voltage value indicates the necessity of measurement. The negative voltage value indicates that measurement is unnecessary. Thus, when the positive voltage indicating that measurement is unnecessary is applied to each base electrode of the switch units24-tand28-tby inverting positive/negative of the potential by the inverter23, the third route is energized. When the negative voltage indicating the necessity of measurement is applied to each base electrode of the switch units24-tand28-t, the third route will be blocked.

The resistance unit20afurther includes switch units25-1and25-2. When the third route is blocked, the switch units25-1and25-2energize any of the first route and the second route, respectively. The switch units25-1and25-2block the first route and the second route when the third route is energized.

More specifically, each base electrode of the switch units25-1and25-2is connected to the CPU151, and a measurement control signal is directly applied from the CPU151to each base electrode. Then, when a positive voltage indicating necessity of measurement is applied to each base electrode of the switch units25-1and25-2, a path from each emitter electrode to each collector electrode of the switch units25-1and25-2can be energized. Note that the voltage regulator22regulates a voltage of a control signal indicating the operation mode from the CPU151and outputs a signal that is obtained by regulating the voltage to the emitter electrode of the switch unit25-2.

Thus, when the control signal that is output from the CPU151has a high voltage value, a positive voltage by the control signal is applied from the emitter electrode of the switch unit25-1via the collector electrode to each base electrode of the switch units24-1and28-1. In that case, a negative voltage is applied from the voltage regulator22via the emitter electrode and the collector electrode of the switch unit25-2to the base electrodes of the switch units24-2and28-2. Therefore, the first route is energized but the second route is blocked.

On the other hand, when the control signal that is output from the CPU151has a low voltage value, a non-positive voltage that is close to 0V by the control signal is applied from the emitter electrode of the switch unit25-1via the collector electrode to each base electrode of the switch units24-1and28-1. In that case, a positive voltage is applied from the voltage regulator22via the emitter electrode and the collector electrode of the switch unit25-2to the base electrodes of the switch units24-2and28-2. Therefore, the first route is blocked but the second route is energized.

As described above, the CPU151determines whether measurement is necessary and outputs a measurement control signal indicating the necessity/unnecessity of measurement separately from the control signal indicating the operation mode. For example, the CPU151may determine the necessity/unnecessity of measurement by referring to schedule information indicating the necessity/unnecessity of measurement for every predetermined time zone. When commands pertaining to maintenance of the information processing device1are indicated by an operation signal that is received from the input device177, the CPU151may determine that measurement is necessary. After a period during which those commands are not indicated continues for a specified time or longer, the CPU151may determine that measurement is unnecessary. The CPU151may display, for example, operating information indicating an operating condition of the system device or each component40on the display165in a predetermined form.

As described above, the resistance unit20ashort-circuits an electric power path from the power supply unit12to the component40when a voltage drop is not measured, in the present embodiment. Thus, when a voltage drop is not measured, unnecessary power consumption due to a detection resistor is avoided. For example, when the information processing device is in a sleep mode, it is possible to save electric power that is consumed by passage of the current through the resistance unit20a.

Third Embodiment

The third embodiment of the present invention and mainly differences from the first embodiment will be described usingFIG. 5. Elements that are common to those of the first embodiment are followed by common symbols and the description thereof is quoted.

The information processing device1according to the present embodiment includes a measurement system2b(FIG. 5) in place of the measurement system2(FIG. 2). The measurement system2bincludes a resistance unit20bin place of the resistance unit20(FIG. 2).

The resistance unit20bincludes a variable resistor26-v. The variable resistor26-vis a resistor whose resistance value can be set to any one of at least two resistance values. The variable resistor26-vincludes a first current terminal, a second current terminal, a control terminal, a resistance element and a movable part (not shown), for example. The first current terminal and the second current terminal are connected to the power supply unit12and the component40, respectively. In addition, the control terminal is connected to the CPU151.

The resistance element is sandwiched between the first current terminal and the second current terminal. Therefore, the variable resistor26-vhas a resistance value that is proportional to the path length of the resistance element between the first current terminal and the second current terminal. The movable part can vary the path length between the first current terminal and the second current terminal in accordance with a control signal that is input to the control terminal. A shape of the resistance element may be any of linear, arc, and helical. By presetting a relationship between voltage values of an arc control signal and the path length, the resistance unit20bcan achieve a resistance value corresponding to the voltage value of the control signal. For example, when the voltage value of the control signal is a high voltage value or a low voltage value, the resistance value of the resistance unit20bcan be set to R1or R2, respectively. Thus, when the operation mode of the CPU151is the standard mode or the sleep mode, the resistance value of the variable resistor26-vis R1or R2, respectively. In addition, the first current terminal and the second current terminal are connected to an input end I and an output end O of the measurement unit30, respectively. The measurement unit30therefore can measure a voltage drop that is generated across the variable resistor26-v.

According to the structure illustrated inFIG. 5, it is thus unnecessary to include a plurality of resistors whose resistance values are different, and a switch unit for energizing a resistor to be measured. In addition, the measurement unit30is not required to have a measurement channel for every resistor or select a measurement channel in accordance with the resistor to be measured. It is therefore possible to make the circuit configuration simple.

Modified Example

Next, a modified example of the above-described embodiment will be described.

FIG. 6illustrates a modified example of the measurement system2according to the above-described embodiment. Although the modified example illustrated inFIG. 6is a modified example of the measurement system2according to the first embodiment, other embodiments may be modified similarly.

The CPU151executes a predetermined application program and performs a function as a measurement information processing unit261. The measurement information processing unit261generates notification screen data for displaying measurement information that is input from the measurement unit30. For example, the measurement information processing unit261may generate notification screen data with the measurement information superimposed at a predetermined position in a notification screen template having a predetermined layout. The measurement information processing unit outputs the generated notification screen data to the display165via the GPU153. The display165functions as a notification unit for notifying a user of the measurement information.

The measurement information processing unit261may determine whether or not the power consumption that is indicated by the measurement information has become an abnormal value. Values that are considered abnormal are typically different in accordance with the type of individual component40. For example, when the component40is the communication module159for wireless communication, it is 0.5 W or more, or 10 mW or less. When the measurement information processing unit261determines that the power consumption has fallen within a range considered to be abnormal, it may display the measurement information in the notification screen data in a display form different from the case within the range of the normal value. The display form is any of elements such as color, brightness, width, size, and decoration, or a combination thereof. For example, the abnormal value may be displayed in a more prominent form than the normal value to easily remind a user of an abnormal operating state.

When the power consumption is larger than an upper limit value of predetermined normal values, the measurement information processing unit261may restart the component40. At this time, the measurement information processing unit261outputs a reset signal to the component40. The component40stops its operation when the reset signal is received from the measurement information processing unit261, and then restarts.

When the power consumption is larger than the upper limit value of predetermined normal values, the measurement information processing unit261may stop the operation of the component40. The measurement information processing unit261may output a predetermined inquiry screen on the display165before stopping the operation. The measurement information processing unit261may stop the operation of the component when an operation signal for instructing a stop of the operation is input from the input device177.

Note that although there is only one component40to be measured in the examples shown inFIGS. 2, 4, and 5, there may be a plurality of components40. In that case, there may be one resistance unit20whose resistance value is variable for each individual component40. In addition, as long as the measurement unit30can independently measure an electric effect that is produced in the individual resistance unit20, the number of the measurement units30does not have to be plural.

In addition, althoughFIG. 1illustrates the case where a processor that functions as a control unit for controlling the operation of the information processing device1is one CPU151and one GPU153each, this is not essential. There may be a plurality of CPUs151and GPUs153, respectively. In addition, the GPU153may be omitted.

Furthermore, in the examples shown inFIGS. 2, 4, and 6, the switch units24-1,24-2,24-t,25-1,25-2,28-1,28-2, and28-tare NPN type transistors, but this is not essential. The switch units24-1,24-2,24-t,25-1,25-2,28-1,28-2, and28-tmay be a switch element whose operating principle is different, including an electromagnetic relay or a thyristor, as long as they can control whether or not to energize in response to a control signal or a measurement control signal.

As described above, the information processing device1according to the present embodiment includes the component40that performs a predetermined operation, the resistance unit20having a variable resistance value, and the measurement unit30that measures a voltage drop in the resistance unit20. The resistance unit20is connected on an electric power line that supplies electric power to the component40.

Since this structure makes the voltage drop in the resistance unit20that is generated by the electric power to the component40variable, it is possible to make the range of voltage drop values variable depending on the operating condition of the component40.

In addition, the information processing device1further includes a control unit (for example, the CPU151) configured to control the operation of the information processing device, the control unit having a first operating state (for example, the standard mode) and a second operating state (for example, the sleep mode) in which power consumption is lower than in the first operating state. The resistance unit20makes its resistance value larger when the operating state of the control unit is the second operating state than that when the operating state is the first operating state.

When the power consumption of the control unit is low, the operation of the component tends to become inactive. However, it is possible to increase the value of the voltage drop that is generated in the resistance unit20as the operation becomes more inactive, and decrease the value of the voltage drop that is generated in the resistance unit20as the operation becomes more active. Thus, it is possible to avoid the reduction in accuracy due to the value of the voltage drop being too small when in the second inactive operating state. Similarly, it is possible to avoid a failure in the operation of the component40due to the value of the voltage drop being too large when in the first active operating state.

In addition, the resistance unit20may include the first resistor26-1, the second resistor26-2whose resistance value is larger than that of the first resistor26-1, and the switch units24and28that energize any one of the first resistor26-1and the second resistor26-2. The resistance unit20energizes the first resistor26-1when the operating state of the control unit is the first operating state and energizes the second resistor26-2when the operating state of the control unit is the second operating state.

This structure can make the resistance value of the resistance unit20variable using the members including the general-purpose resistors26-1and26-2, and the switch units24and28. Thus, it is possible to economically avoid the reduction in measurement accuracy of the voltage drop and the failure in the operation of the component40.

In addition, the control unit may short-circuit the resistance unit20when a voltage drop is not measured. Since no electric resistance is generated in the resistance unit20when a voltage drop is not measured, this structure can reduce power consumption due to electric resistance.

In addition, the information processing device1further includes a measurement information notification unit265that notifies of measurement information on a voltage drop. This structure makes it possible for a user to grasp the operating state of the component40more accurately since measurement information (for example, power consumption) based on the voltage drop measured with higher accuracy is notified.

Although the embodiments of the present invention have been described in detail with reference to the drawings, specific structures are not limited to the above-described embodiments and design etc. without departing from the scope of the invention is also included. Each structure described in the above-described embodiments can be combined optionally.

DESCRIPTION OF SYMBOLS