JP3976034B2 - Information terminal and battery remaining charge calculation method - Google Patents

Description

  The present invention relates to an information terminal and a battery remaining amount calculation method.

  Examples of small information terminals using a battery include a digital camera, a portable video playback device, and a portable still image playback device. Recently, devices such as hard disk drives that have a large effect on load fluctuations have been installed in such small information terminals. For this reason, the load on the battery varies greatly depending on the driving state of such devices. It is supposed to be.

Accurate display of the remaining battery level is very important for the user as a means of estimating how much the information terminal can be used. As a method for detecting the remaining battery level, a method for measuring the charge / discharge current of the battery (for example, see JP-A-5-66251 and JP-A-7-260839), and a method for measuring the battery voltage (for example, JP-A-6-51876 and JP-A-11-55372).
Japanese Patent Laid-Open No. 5-66251 JP 7-260839 A JP-A-6-51876 Japanese Patent Laid-Open No. 11-55372

  However, the method for measuring the charge / discharge current requires a current measurement unit, a storage unit for storing the measured current data, and a CPU for calculating the remaining battery capacity from the data, which hinders downsizing and cost reduction. To do. For this reason, it is not suitable for a small information terminal.

  On the other hand, in the method of measuring the battery voltage, the external voltage changes due to the internal impedance when the load fluctuates as the characteristics of the battery. For this reason, an information terminal incorporating a device with a large load fluctuation cannot accurately detect the remaining battery level. For example, since the load becomes large when the information terminal is turned on, the remaining amount of battery is displayed low. After that, when the information terminal is stabilized, the load is reduced and the remaining amount of battery increases. Such a display change of the remaining battery level is confusing for the user and very inconvenient.

  As a method of correcting the influence of the load fluctuation, there is a method of measuring and correcting the current flowing through the load, as disclosed in Japanese Patent Laid-Open No. 5-66251. However, additional parts such as a current detection unit and a comparison voltage correction unit are required, resulting in an increase in cost. In addition, in an information terminal that must be downsized, it is desirable to avoid adding new components for the purpose of detecting the remaining battery level as much as possible. In addition, inserting a current detection resistor in the power supply line causes a voltage drop and wasteful power consumption, and is not suitable for information terminals that want to extend the battery driving time as much as possible. .

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to reduce the size of an information terminal while enabling display of a remaining battery level corrected for the influence of load fluctuations.

In order to solve the above problems, an information terminal according to the present invention provides:
An information terminal driven by a battery,
A voltage detector that detects a battery voltage that is a voltage of the battery;
A drive unit that is driven by power supplied from the battery; and
A load calculating unit that monitors a load on the battery of the driving unit and calculates the load according to an operating state of the driving unit;
A remaining battery level calculation unit for calculating a remaining battery level based on the battery voltage, wherein the remaining battery level calculation unit calculates a corrected remaining battery level based on the load calculated by the load calculation unit; ,
With
The drive unit includes a hard disk drive, and the hard disk drive has a plurality of states with different current consumption depending on its operation state even when the hard disk drive is not accessed.
The load calculating unit obtains a load of the hard disk drive based on a time during which the hard disk drive is accessed and a time during which each hard disk drive is in an operation state when the hard disk drive is not accessed. The operating state of the hard disk drive when there is no hard disk drive is determined on the basis of the duration during which the hard disk drive is not accessed.

  In this case, the driving unit also includes the central processing unit of the information terminal, and the load calculation unit may determine the load of the central processing unit based on the operation mode of the central processing unit. Good.

  The load calculation unit may also determine a load on the battery based on processing content processed by the information terminal.

The driving unit also includes an LCD backlight, and the load calculating unit calculates an LCD backlight luminance coefficient of the LCD backlight based on the luminance of the LCD backlight, and the LCD backlight luminance The load on the LCD backlight may also be obtained based on the coefficient.

The information terminal further includes a temperature detection unit that detects a battery temperature that is the temperature of the battery,
The battery remaining amount calculating unit may calculate a remaining battery level corrected based on the battery temperature detected by the temperature detecting unit.

  The information terminal may further include a display unit that displays the remaining battery level calculated by the remaining battery level calculating unit.

  In addition, the information terminal indicates how much time the information terminal can be used based on the remaining battery level calculated by the remaining battery level calculation unit and the load calculated by the load calculation unit. You may make it further provide the remaining usable time calculation part which calculates possible time.

A battery remaining amount calculating method according to the present invention is a battery remaining amount calculating method in an information terminal driven by a battery,
Detecting a battery voltage which is a voltage of the battery;
Monitoring the load on the battery of the drive unit that is driven by the supply of power from the battery, and calculates the load according to the operating state of the drive unit;
In calculating the remaining battery level based on the battery voltage, calculating the corrected battery level based on the calculated load,
The drive unit includes a hard disk drive, and the hard disk drive has a plurality of states with different current consumption depending on the operation state even when the hard disk drive is not accessed.
When calculating the load, the load of the hard disk drive is obtained based on the time during which the hard disk drive is accessed and the time during which the hard disk drive is not accessed. The operating state of the hard disk drive when it is not accessed is determined based on the duration during which the hard disk drive is not accessed.

A program according to the present invention is a program for causing an information terminal driven by a battery to calculate a remaining battery capacity,
Detecting a battery voltage which is a voltage of the battery;
Monitoring the load on the battery of the drive unit that is driven by receiving power supply from the battery, and calculating the load according to the operating state of the drive unit;
In calculating the remaining battery level based on the battery voltage, calculating the corrected battery level based on the calculated load;
To the information terminal,
The drive unit includes a hard disk drive, and the hard disk drive has a plurality of states with different current consumption depending on the operation state even when the hard disk drive is not accessed.
In the step of calculating the load, the load of the hard disk drive is obtained and the hard disk drive is accessed based on the time during which the hard disk drive is accessed and the time during which the hard disk drive is not accessed. The operation state of the hard disk drive when it is not performed is determined based on the duration time during which the hard disk drive is not accessed.

[First Embodiment]
In the first embodiment, in a small information terminal incorporating a device with a large load fluctuation, in calculating the battery remaining amount, the influence of the load variation is corrected and the remaining battery amount can be obtained with high accuracy. Is. More details will be described below.

  FIG. 1 is a block diagram illustrating an example of the internal configuration of the information terminal according to the present embodiment. As shown in FIG. 1, the information terminal includes a CPU 10, an LCD backlight 12, a hard disk drive 14, a display unit 18, and another load 16. In addition, the information terminal includes a battery 20, and the power supplied from the battery 20 is connected to the CPU 10, the LCD backlight 12, the hard disk drive 14, the display unit 18, and the like via the DC / DC converter 22. To the other load 16. In other words, the voltage stabilized or transformed by the DC / DC converter 22 is supplied to the drive unit as these loads. The CPU 10 includes an AD converter 30, a RAM 32, and a ROM 34 inside. The CPU 10 constitutes a central processing unit in the present embodiment.

  The information terminal also includes a voltage detection circuit 40. This voltage detection circuit detects the voltage between the battery 20 and the DC / DC converter 22, and supplies the detected value to the AD converter 30 of the CPU 10 as the battery voltage. The CPU 10 converts the detected value into digital data and imports it into the CPU 10.

  The battery 20 includes a temperature detection circuit 42. The temperature detection circuit 42 is composed of, for example, a thermistor, and an analog signal output from the temperature detection circuit 42 is input to the AD converter 30 and taken into the CPU 10 as digital data.

  Next, based on FIG. 2, the principle of the battery remaining amount calculation according to the present embodiment will be described. FIG. 2 is a graph showing the relationship between the battery voltage and the remaining battery level when the load is large (for example, 1200 mA) and when the load is small (for example, 400 mA). As can be seen from this graph, even if the measured battery voltage is the same value, the actual remaining battery level differs between when the load is large and when the load is small. Therefore, in this embodiment, the relationship between the battery voltage and the remaining battery level is prepared in advance in a table for some typical load values. And when calculating the remaining battery level, the load of the information terminal is calculated, and when determining the remaining battery level based on the measured battery voltage, a correction according to the load is performed to obtain a more accurate The battery remaining amount can be calculated.

  FIG. 3 is a diagram illustrating a flowchart for explaining the content of the remaining battery level calculation process according to the present embodiment. The battery remaining amount calculation process shown in FIG. 3 is a process realized by the CPU 10 reading and executing a battery remaining amount calculating process program stored in the ROM 34.

  As shown in FIG. 3, the information terminal acquires a battery voltage that is a voltage of the battery 20 (step S10). That is, the voltage of the battery 20 detected by the voltage detection circuit 40 is acquired as digital data via the AD converter 30.

  Next, the information terminal acquires the battery temperature that is the temperature of the battery 20 (step S12). That is, the battery temperature of the analog data detected by the temperature detection circuit 42 provided inside the battery 20 is acquired as digital data via the AD converter 30.

  Next, the information terminal acquires a steady load (step S14). This steady load varies depending on the operation mode of the CPU 10. In the present embodiment, the CPU 10 is assumed to have three operation modes of low speed, medium speed, and high speed. Of these three operation modes, the CPU 10 knows which one is currently in operation. In this embodiment, the steady load is 400 mA at low speed, the steady load is 500 mA at medium speed, and the steady load is 600 mA at high speed.

  Next, the information terminal acquires the hard disk drive operating rate (step S16). In the present embodiment, the hard disk drive 14 outputs to the CPU 10 an access signal indicating whether access is being made. Therefore, the CPU 10 can acquire this access signal and calculate the ratio between the time when the hard disk drive 14 is accessed and the time when it is not accessed at any time. In this embodiment, the ratio of this access time is defined as the hard disk drive operating rate.

  Next, the information terminal acquires an LCD backlight luminance coefficient (step S18). In the present embodiment, the CPU 10 outputs a luminance signal for controlling the luminance of the LCD backlight 12 to the LCD backlight 12. Therefore, the CPU 10 can grasp the luminance coefficient of the LCD backlight 12 based on this luminance. In the present embodiment, the LCD backlight luminance coefficient is configured to be set in increments of 10% between 0% and 100%.

Next, the information terminal calculates a load (step S20). In the present embodiment, the load is obtained by the following equation.

  In this embodiment, the hard disk drive access load is, for example, 500 mA, and the LCD load is, for example, 100 mA. The current load can be calculated by substituting the steady load acquired in step S14, the hard disk drive operating rate acquired in step S16, and the LCD backlight luminance coefficient acquired in step S18 into this equation.

  Next, the information terminal generates a voltage-remaining amount conversion table corresponding to the battery temperature (step S22). In the present embodiment, four types of temperature-dependent voltage-remaining amount conversion tables are stored in the ROM 34 in the CPU 10. 4 to 7 are diagrams showing examples of these four types of temperature-dependent voltage-residual amount conversion tables TB10 to TB40. 4 is a diagram showing a voltage-remaining amount conversion table TB10 when the battery temperature is 5 ° C., and FIG. 5 is a diagram showing a voltage-remaining amount conversion table TB20 when the battery temperature is 15 ° C. FIG. 6 is a diagram showing a voltage-remaining amount conversion table TB30 when the battery temperature is 25 ° C., and FIG. 7 is a diagram showing a voltage-remaining amount conversion table TB40 when the battery temperature is 45 ° C.

  As can be seen from these figures, in the present embodiment, the relationship between the remaining amount and the battery voltage is tabulated using three cases of loads of 400 mA, 800 mA, and 1200 mA as representative values. Then, using these voltage-remaining amount conversion tables, a voltage-remaining amount conversion table at the battery temperature acquired in step S12 is generated by a linear interpolation method.

For example, it is assumed that the battery temperature acquired in step S12 is 20 ° C. In this case, by linearly interpolating the voltage value of the 15 ° C. voltage-residual amount conversion table TB20 shown in FIG. 5 and the voltage value of the 25 ° C. voltage-residual amount conversion table TB30 shown in FIG. The voltage value of the voltage-residual amount conversion table TB50 is generated. Specifically, the temperature of the low voltage side voltage-residual conversion table is T1 (15 ° C.), the temperature of the high voltage side voltage-residual conversion table is T2 (25 ° C.), and the battery temperature is T (20 ° C.). ), And Y1 is a voltage value at T1, and Y2 is a voltage value at T2, the corrected voltage Y can be calculated by the following equation.

  The voltage-remaining amount conversion table TB50 when the battery temperature calculated in this way is 20 ° C. is as shown in FIG. This voltage-remaining amount conversion table TB50 is stored in the RAM 32 of the CPU 10.

  In this embodiment, when the battery temperature is lower than 5 ° C., a voltage-remaining amount conversion table of 5 ° C. and 15 ° C. is used, and when the battery temperature is higher than 45 ° C., the voltage-remaining amount of 25 ° C. and 45 ° C. By using the conversion table and substituting it into Equation (2), a voltage-residual amount conversion table for those temperatures is obtained.

  Next, as shown in FIG. 3, the information terminal generates a voltage-residual amount conversion table corresponding to the load calculated in step S20 (step S24). That is, based on the voltage-residual amount conversion table generated in step S22, a voltage-residual amount conversion table corresponding to the load calculated in step S20 is generated and stored in the RAM 32.

For example, assume that the load calculated in step S20 is 1000 mA. In this case, the voltage value in the case of 800 mA in the voltage-residual amount conversion table TB50 shown in FIG. 8 and the voltage value in the case of 1200 mA are linearly interpolated to obtain the voltage value of the voltage-residual amount conversion table TB60 of 1000 mA. Is generated. Specifically, the current value on the low load side is L1 (800 mA), the current value on the high load side is L2 (1200 mA), the load calculated in step S20 is L, and Y1 is the voltage value at L1, When Y2 is a voltage value at the time of L2, the corrected voltage Y can be calculated by the following equation.

  The voltage-residual amount conversion table TB60 when the calculated load is 1000 mA is as shown in FIG.

  Next, as illustrated in FIG. 3, the information terminal calculates the remaining battery level based on the voltage-remaining amount conversion table TB60 after performing load correction and temperature correction (step S26). That is, the battery remaining amount corresponding to the battery voltage acquired in step S10 is calculated by linearly interpolating the numerical value of the voltage-remaining amount conversion table TB60 stored in the RAM 32.

For example, it is assumed that the battery voltage acquired in step S10 is 3.55V. In this case, the battery voltage becomes 3 by linearly interpolating 3.54V (battery remaining capacity 40%) and 3.60V (battery remaining capacity 50%) in the voltage-remaining capacity conversion table TB60 shown in FIG. Calculate the remaining battery level for .55V. Specifically, the voltage value on the low voltage side is Y1 (3.54V), the voltage value on the high voltage side is Y2 (3.60V), the voltage acquired in step S10 is Y, and X1 is Y1. When the remaining battery level is X2 and the remaining battery level at Y2 is X2, the corrected battery level X can be calculated by the following equation.

  As a result, the remaining voltage is calculated to be about 42%. In the present embodiment, the calculated remaining battery level is temporarily stored in the RAM 32.

  Next, as shown in FIG. 3, the information terminal reads the remaining battery level calculated from the RAM 32 and displays it on the display unit 18 (step S28). Various methods for displaying the remaining battery level are conceivable. For example, the screen of the information terminal may be displayed as 42% as a numerical value, or the display unit 18 may be constituted by a bar-type liquid crystal display unit, and the bar length of the liquid crystal display unit may be The length may be equivalent to 42%.

  As described above, according to the present embodiment, a signal that the device outputs the operating rate of a device that contributes to load fluctuations (for example, the hard disk drive 14, the LCD backlight 12, and the operation mode of the CPU 10). Alternatively, it is calculated by measuring a received signal, and correction is performed based on the calculation result so that the remaining battery level is displayed accurately. In addition, since correction is performed using the CPU 10 that is originally incorporated in the information terminal, it is not necessary to add a new device, and the information terminal can be reduced in size and cost.

  Furthermore, since the battery temperature of the battery 42 is detected using the temperature detection circuit 42 and correction is also performed based on the battery temperature, the remaining battery level can be displayed with higher accuracy.

[Second Embodiment]
In the first embodiment described above, the hard disk drive operating rate is calculated based on the access signal of the hard disk drive 14 and the load on the hard disk drive 14 is calculated. In the second embodiment, the state of the hard disk drive 14 is changed. The load of the hard disk drive 14 is determined more accurately by specifying more accurately.

  Specifically, it is assumed that the hard disk drive 14 in this embodiment has five operation states as shown in FIGS. That is, an access state (hereinafter referred to as an AC load) in which the hard disk drive 14 is actually accessed, a performance idle state (hereinafter referred to as a PI load) for 300 ms after the end of access, and 10 seconds after the end of the performance idle state. Active idle state (hereinafter referred to as AI load), low power idle state (hereinafter referred to as LPI load) after the end of the active idle state, and standby state (hereinafter referred to as ST load) that shifts based on instructions from the CPU 10 As an operating state.

  In this embodiment, the current consumption is 600 mA in the access state, the current consumption is 400 mA in the performance idle state, the current consumption is 190 mA in the active idle state, and the current consumption is 170 mA in the low power idle state. In the standby state, the current consumption is 40 mA. In the present embodiment, the state of the hard disk drive 14 is sampled 32 times per second. In other words, the operating state of the hard disk drive 14 is specified with a sampling period of 31.25 ms.

  Further, the access signal in the first embodiment is at a low level when the hard disk drive 14 is in the access state, and is at a high level when it is not in the access state.

  Therefore, in the present embodiment, even if the access signal indicates a state of no access, whether the hard disk drive 14 is in the performance idle state, the active idle state, the low power idle state, The current consumption varies greatly depending on whether it is in the standby state. For this reason, the load on the hard disk drive 14 cannot be accurately calculated simply by detecting and counting the high level and low level of the access signal.

  For example, as shown in FIG. 12, the access state, the performance idle state, the access state, the performance idle state, the access state, and the performance idle state transit in order, and as shown in FIG. 13, the access state It is clear when the performance idle state, active idle state, and access state are sequentially compared.

  In FIG. 12 and FIG. 13, the number of times the low level access signal (that is, the access state) is counted in one second is the same at six times. However, the load on the hard disk drive 14 is 438 mA in the case of FIG. 12, 333 mA in the case of FIG. 13, and the difference is 105 mA. When the load of the hard disk drive 14 is calculated based only on the access signal indicating whether or not the hard disk drive 14 is being accessed, this exists as a potential error.

Therefore, in the present embodiment, the load of the hard disk drive 14 is calculated using the following equation (5).

  That is, since sampling is performed 32 times per second, the current consumption per second of the hard disk drive 14 is calculated based on the state obtained by sampling. Here, the counter N_ON is a count number when the hard disk drive 14 is in the access state in the immediately preceding 1 second, and the counter N_OFF_PI is a count when the hard disk drive 14 is in the performance idle state in the immediately preceding 1 second. The counter N_OFF_AI is a count number when the hard disk drive 14 is in an active idle state in the immediately preceding 1 second, and the counter N_OFF_LPI is in a low power idle state in the immediately preceding 1 second. The counter N_OFF_ST is a count number when the hard disk drive 14 is in a standby state in the immediately preceding 1 second. That is, the counters N_ON, N_OFF_PI, N_OFF_AI, N_OFF_LPI, and N_OFF_ST are variables that are cleared to zero every second.

  Since the standby state (ST load) is shifted by issuing an instruction from the CPU 10 to the hard disk drive 14, this standby state can be specified by the CPU 10 itself.

In addition, the load of the entire information terminal is calculated by Expression (6) instead of Expression (1) in the first embodiment.

  FIG. 14 is a block diagram illustrating an example of the internal configuration of the information terminal according to the present embodiment. As can be seen from FIG. 14, the internal configuration of the information terminal according to the present embodiment is roughly the same as that of the first embodiment described above, but the hard disk drive 14 is set in the standby state from the CPU 10 to the hard disk drive 14. The difference is that a command signal for shifting to a state is output. In other words, in the present embodiment, the CPU 10 outputs the command signal from the CPU 10 to the hard disk drive 14 in order to actively shift the hard disk drive 14 to the standby state. Normally, the command signal for shifting to the standby state is output when the hard disk drive 14 is in the low power idle state. Other configurations are the same as those in the first embodiment described above.

  Next, hard disk drive load count processing in this embodiment will be described. FIG. 15 is a flowchart illustrating the contents of the hard disk drive load count process according to the present embodiment. The hard disk drive load count process shown in FIG. 15 is a process realized by the CPU 10 reading and executing a hard disk drive load count process program stored in the ROM 34. Further, as described above, the hard disk drive load count process is started and counted every 31.25 ms.

  As shown in FIG. 15, the information terminal determines whether or not the hard disk drive 14 is in an active state (step S100). Specifically, it is determined whether or not the access signal of the hard disk drive 14 indicates an accessing state. When the hard disk drive 14 is in the active state (step S100: Yes), the counter N_ON is incremented by one (step S102).

  On the other hand, if the hard disk drive 14 is not in the active state (step S100: No), it is determined whether or not the hard disk drive 14 is in the standby state (step S104). Specifically, since the CPU 10 outputs a command signal for shifting the hard disk drive 14 to the standby state, the CPU 10 can grasp whether the hard disk drive 14 is in the standby state. For this reason, the CPU 10 itself determines whether or not the hard disk drive has been put into a standby state. When the hard disk drive 14 is in the standby state (step S104: Yes), the counter N_OFF_ST is incremented by one (step S106).

  On the other hand, when it is determined that the hard disk drive 14 is not in the standby state (step S104: No), it is determined whether or not the access signal has been continuously in the non-access state for more than 10 samplings (step S108). Specifically, the CPU 10 starts counting the number of consecutive non-accesses from zero immediately after shifting from a state where the access signal is accessed (low level) to a state where the access signal is not accessed (high level). At this time, when the state of not being accessed continues, a process of counting up the number of consecutive non-accesses by one is performed.

  Then, the CPU 10 determines whether or not the continuous non-access number has continued more than ten times. As described above, in the present embodiment, the performance idle state is a setting that continues for 300 ms when there is no access. For this reason, in the present embodiment in which sampling is performed every 31.25 ms, the performance idle state corresponds to a sampling time of 10 times, and therefore, the number of times the access signal that has been continuously in the non-access state is sampled 10 times or less. In this case, it can be determined that the system is in the performance idle state. When the number of consecutive non-accesses is 10 times or less (step S108: No), the counter N_OFF_PI is incremented by one (step S110).

  On the other hand, if the number of consecutive non-accesses is greater than 10 (step S108: Yes), it is determined whether or not the number of consecutive non-accesses is greater than 10 + 320 = 330 (step S112). Specifically, the CPU 10 determines whether or not the number of consecutive non-accesses is greater than 330 times. As described above, in this embodiment, the performance idle state is set to continue for 300 ms, and then the active idle state is set to continue for 10 seconds. For this reason, in this embodiment in which sampling is performed every 31.25 ms, the performance idle state corresponds to a time for sampling 10 times, and the active idle state corresponds to a time for sampling 320 times. If the number of consecutive non-accesses indicating the number of times of sampling is greater than 10 and less than or equal to 330, it can be determined that the active idle state exists. When the number of consecutive non-accesses is 330 times or less (step S112: No), the counter N_OFF_AI is incremented by one (step S114).

  On the other hand, when the number of consecutive non-accesses is greater than 330 (step S112: Yes), the counter N_OFF_LPI is incremented by one (step S116).

  The hard disk drive load count processing according to the present embodiment is completed by the processing of step S102, step S106, step S110, step S114, and step S116.

  Next, the battery remaining amount calculation process in this embodiment will be described. FIG. 16 is a diagram illustrating a flowchart for explaining the content of the remaining battery charge calculation process according to the present embodiment. The remaining battery level calculation process shown in FIG. 16 is a process realized by the CPU 10 reading and executing the remaining battery level calculation process program stored in the ROM 34. In the present embodiment, the remaining battery level calculation process is a process that is started at a rate of once per second.

  As shown in FIG. 16, the information terminal acquires a battery voltage that is a voltage of the battery 20 (step S10). That is, the voltage of the battery 20 detected by the voltage detection circuit 40 is acquired as digital data via the AD converter 30.

  Next, the information terminal acquires the battery temperature that is the temperature of the battery 20 (step S12). That is, the battery temperature of the analog data detected by the temperature detection circuit 42 provided inside the battery 20 is acquired as digital data via the AD converter 30.

  Next, the information terminal acquires a steady load (step S14). This steady load varies depending on the operation mode of the CPU 10. In the present embodiment, the CPU 10 is assumed to have three operation modes of low speed, medium speed, and high speed. Of these three operation modes, the CPU 10 knows which one is currently in operation. In this embodiment, the steady load is 400 mA at low speed, the steady load is 500 mA at medium speed, and the steady load is 600 mA at high speed.

  Next, the information terminal acquires the load of the hard disk drive 14 (step S200). In the present embodiment, the load on the hard disk drive 14 is calculated based on the above-described equation (5). That is, the hard disk drive load count process calculates the load on the hard disk drive 14 based on the result of sampling the state of the hard disk drive 14 during the previous one second. Specifically, by substituting the N_ON count number, N_OFF_PI counter number, N_OFF_AI count number, N_OFF_LPI count number, and N_OFF_ST count number in the previous one second into the formula (5), the current hard disk The load on the drive 14 is calculated.

  Next, these counters N_ON, N_OFF_PI, N_OFF_AI, N_OFF_LPI, and N_OFF_ST are cleared and set to zero (step S202).

  Next, the information terminal acquires an LCD backlight luminance coefficient (step S18). In the present embodiment, the CPU 10 outputs a luminance signal for controlling the luminance of the LCD backlight 12 to the LCD backlight 12. Therefore, the CPU 10 can grasp the luminance coefficient of the LCD backlight 12 based on this luminance. In the present embodiment, the LCD backlight luminance coefficient is configured to be set in increments of 10% between 0% and 100%.

  Next, the information terminal calculates the overall load (step S20). In the present embodiment, the entire load is calculated based on the above-described equation (6). Since the subsequent processing is the same as that of the first embodiment described above, description thereof is omitted. In addition, the voltage-to-residual conversion tables TB10 to TB40 for each temperature included in the information terminal according to the present embodiment are the same as those in FIGS. 4 to 7 in the first embodiment described above, and thus the description thereof is omitted.

  As described above, according to the present embodiment, the load on the hard disk drive 14 is calculated with higher accuracy based on the operating state of the hard disk drive 14. For this reason, the remaining battery level can be displayed with higher accuracy.

  FIG. 17 is a graph showing the relationship between the elapsed time and the remaining battery level when the correction is performed according to the operating state of the hard disk drive 14 (this embodiment) and when the correction is not performed. ing. In FIG. 17, the case where correction is not performed according to the operating state of the hard disk drive 14 indicates a case where the state in which the hard disk drive 14 is not in the access state is calculated based on the consumption current in the performance idle state.

  As can be seen from FIG. 17, when the access ratio of the hard disk drive 14 is 100% of the total, the accuracy does not change regardless of whether correction is performed. However, if the access ratio of the hard disk drive 14 is 6% of the total, the correction will cause the load on the hard disk drive 14 to be estimated more than it would be if there was no correction. I can see it falling.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the embodiment described above, the remaining battery level is displayed as it is, but this may be converted into the remaining usable time and displayed. In other words, what the user really wants to know is information on how much the information terminal can be used in the same way as it is now. In the embodiment described above, even an information terminal having a large load fluctuation can estimate the fluctuation of the load, and therefore the remaining usable time can be calculated based on the value of the load and the remaining battery level. Of course, this may be displayed in real time. As a result, for example, when a user is viewing a video, it is possible to accurately know how much can be viewed later, or how much data can be transferred later when backing up data. Can know with high accuracy.

  In the above-described embodiment, the LCD backlight 12, the hard disk drive 14, and the CPU load are taken as examples of the drive unit elements having large load fluctuations, but other drive unit elements may be added. Alternatively, some of the elements of the drive unit can be omitted. For example, since the influence of the load fluctuation is not so great, the LCD backlight 12 may not be considered when calculating the load. Alternatively, these driving elements may calculate the load as a constant constant. For example, the LCD backlight 12 may calculate the load with a constant value of 100 mA regardless of the luminance coefficient.

  Further, the current consumption used in the above-described embodiment and the time for maintaining each state of the hard disk drive 14 are merely exemplary, and may vary depending on the model number of the hard disk drive 14 and the firmware that controls the current. is there.

  In the above-described embodiment, the steady load is determined based on the operation mode of the CPU 10, but the steady load may be changed depending on the operation mode of the information terminal. For example, as shown in FIG. 18, as the processing content executed by the information terminal, when USB data transfer is performed, the steady load is 200 mA, and when still image reproduction is performed, the steady load is 400 mA. When moving image reproduction is performed, the steady load may be set to 450 mA. This determination may be performed in step S14 described above. Thereby, when there are a plurality of types of processing performed in the information terminal, the steady load can be obtained easily and accurately.

  For each process described in the above-described embodiment, a program for executing each process is recorded on a recording medium such as a flexible disk, a CD-ROM (Compact Disc-Read Only Memory), a ROM, or a memory card. Thus, it can be distributed in the form of a recording medium. In this case, the above-described embodiment can be realized by causing the information terminal to read and execute the recording medium on which the program is recorded.

  In addition, the information terminal may include another program such as an operating system or another application program. In this case, the other program provided in the information terminal is utilized, and the recording medium is recorded with an instruction for calling a program that realizes the same processing as the above-described embodiment from among the programs provided in the information terminal. May be.

  Furthermore, such a program can be distributed not as a recording medium but as a carrier wave through a network. The program transmitted in the form of a carrier wave on the network is taken into the information terminal, and the above-described embodiment can be realized by executing this program.

  Also, when a program is recorded on a recording medium or transmitted as a carrier wave on a network, the program may be encrypted or compressed. In this case, the information terminal that has read the program from the recording medium or the carrier wave needs to execute the program after decoding or decompressing the program.

  Furthermore, the above-described processing can be realized by hardware as shown in FIG. In FIG. 19, the control unit 100 is configured by hardware such as an ASIC. In the example of FIG. 19, the control unit 100 includes a load calculation unit 102, a battery remaining amount calculation unit 104, and a remaining usable time calculation unit 106.

  The load calculation unit 102 calculates the load on the battery 20 in this information terminal. The remaining battery level calculation unit 104 calculates the remaining battery level based on the battery voltage. At this time, the remaining battery level calculated based on the load calculated by the load calculation unit 102 is calculated.

  Further, the load calculation unit 102 calculates a hard disk operation rate based on the ratio between the time when the hard disk drive 14 is accessed and the time when the hard disk drive 14 is not accessed, and the load of the hard disk drive 14 based on the hard disk operation rate Ask for.

  In addition, even when the hard disk drive 14 is not accessed, the load calculating unit 102 determines that the hard disk drive 14 has a plurality of states with different current consumption depending on the operation state. The load of the hard disk drive 14 is obtained based on the time during which the hard disk drive 14 is being accessed and the time during which the hard disk drive is not being accessed.

  Further, the load calculation unit 102 acquires the operation mode of the CPU 10 and obtains the load of the CPU 10 based on the operation mode. Furthermore, the load calculation unit 102 obtains the load on the battery 20 based on the processing content processed by the information terminal.

  Further, the load calculation unit 102 acquires the luminance of the LCD backlight 12, calculates the LCD backlight luminance coefficient of the LCD backlight 12 based on the luminance, and the LCD backlight based on the LCD backlight luminance coefficient. Find the load. In addition, the battery remaining amount calculation unit 104 obtains the battery temperature that is the temperature of the battery 20, and calculates the battery remaining amount corrected based on the battery temperature when calculating the battery remaining amount.

  The specific processing content for calculating the load by the load calculating unit 102 and the specific processing content for calculating the remaining battery amount by the battery remaining amount calculating unit 104 are the same as the processing content of FIG. 3 or FIG. It is.

  Further, the display unit 18 displays the remaining battery level calculated by the remaining battery level calculation unit 104. Further, the remaining usable time calculation unit 106 indicates how much time this information terminal can be used based on the remaining battery level calculated by the remaining battery level calculation unit 104 and the load calculated by the load calculation unit 102. The remaining usable time is calculated.

The block diagram explaining an example of the composition of the information terminal concerning a 1st embodiment. The figure which shows the graph of the relationship between a battery voltage and a battery remaining charge. The figure which shows the content of the battery remaining charge calculation process which concerns on 1st Embodiment, and the flowchart explaining the content of a part of battery remaining charge calculation process which concerns on 2nd Embodiment. The figure which shows an example of the 5 degreeC voltage-residual amount conversion table which the information terminal which concerns on 1st Embodiment and 2nd Embodiment has. The figure which shows an example of the 15 degreeC voltage-residual amount conversion table which the information terminal which concerns on 1st Embodiment and 2nd Embodiment has. The figure which shows an example of the 25 degreeC voltage-residual amount conversion table which the information terminal which concerns on 1st Embodiment and 2nd Embodiment has. The figure which shows an example of the 45 degreeC voltage-residual amount conversion table which the information terminal which concerns on 1st Embodiment and 2nd Embodiment has. FIG. 6 is a diagram illustrating an example of a 20 ° C. voltage-residual conversion table generated from the 15 ° C. voltage-residual conversion table and the 25 ° C. voltage-residual conversion table shown in FIG. 5; The figure which shows an example of the 1000 mA voltage-residual amount conversion table produced | generated from the 20 degreeC voltage-residual amount conversion table shown in FIG. The figure which shows the table showing the relationship between the operation state of the hard disk drive in the information terminal which concerns on 2nd Embodiment, and its consumption current. The figure which shows an example of the transition of the operating state of the hard disk drive in the information terminal which concerns on 2nd Embodiment, and current consumption. The figure which shows an example of the transition of the operation state of the hard-disk drive in the information terminal which concerns on 2nd Embodiment. The figure which shows an example of the transition of the operation state of the hard-disk drive in the information terminal which concerns on 2nd Embodiment. The block diagram explaining an example of the structure of the information terminal which concerns on 2nd Embodiment. The figure which shows the flowchart explaining the content of the hard-disk drive load count process which concerns on 2nd Embodiment. The figure which shows the flowchart explaining the one part content of the battery remaining charge calculation process which concerns on 2nd Embodiment. The figure which shows the graph showing the relationship between the elapsed time in the case where correction | amendment according to the operation state of a hard-disk drive, and the case where correction | amendment is not carried out, and a battery remaining charge. The figure which shows an example which calculates a steady load according to the processing content of an information terminal. The figure which shows an example of a structure at the time of implement | achieving battery remaining charge calculation processing with hardware.

Explanation of symbols

10 CPU
12 LCD backlight 14 Hard disk drive 16 Other load 18 Display unit 20 Battery 22 DC / DC converter 30 AD converter 32 RAM
34 ROM
40 Voltage detection circuit

Claims (9)

An information terminal driven by a battery,
A voltage detector that detects a battery voltage that is a voltage of the battery;
A drive unit that is driven by power supplied from the battery; and
A load calculating unit that monitors a load on the battery of the driving unit and calculates the load according to an operating state of the driving unit;
A remaining battery level calculation unit for calculating a remaining battery level based on the battery voltage, wherein the remaining battery level calculation unit calculates a corrected remaining battery level based on the load calculated by the load calculation unit; ,
Equipped with a,
The drive unit includes a hard disk drive, and the hard disk drive has a plurality of states with different current consumption depending on the operation state even when the hard disk drive is not accessed.
The load calculation unit obtains the load of the hard disk drive based on the time during which the hard disk drive is accessed and the time during which each hard disk drive is in the operating state, and the hard disk drive is accessed. An information terminal characterized in that an operating state of a hard disk drive in the absence of the hard disk drive is determined based on a duration during which the hard disk drive is not accessed . The central processing unit of the information terminal is included in the driving unit, and the load calculation unit also obtains the load of the central processing unit based on an operation mode of the central processing unit. Item 4. The information terminal according to Item 1 . The load calculation unit, the information terminal according to claim 1 or claim 2 the information load on based rather the battery to the processing contents to be processed by the terminal also obtains, be characterized. The drive unit also includes an LCD backlight, and the load calculation unit calculates an LCD backlight luminance coefficient of the LCD backlight based on the luminance of the LCD backlight, and the LCD backlight luminance coefficient information terminal according to any one of claims 1 to 3 LCD backlight load also determined, characterized in that on the basis of. A temperature detection unit for detecting a battery temperature that is the temperature of the battery;
The battery remaining amount calculating unit, information according to any one of claims 1 to 4 wherein calculating the battery remaining amount to the correction based on the battery temperature detected by the temperature detection unit, characterized in that Terminal. The battery level calculator displays the remaining battery capacity calculated, the information terminal according to any one of claims 1 to 5, characterized in that it further includes a display unit. Based on the battery remaining amount calculated by the battery remaining amount calculating unit and the load calculated by the load calculating unit, a remaining usable time indicating how much time the information terminal can be used is calculated; information terminal according to any one of claims 1 to 6, characterized by further comprising a remaining usable time calculating unit. A battery remaining amount calculation method in an information terminal driven by a battery,
Detecting a battery voltage which is a voltage of the battery;
Monitoring the load on the battery of the drive unit that is driven by the supply of power from the battery, and calculates the load according to the operating state of the drive unit;
In calculating the remaining battery level based on the battery voltage, calculating the corrected battery level based on the calculated load ,
The drive unit includes a hard disk drive, and the hard disk drive has a plurality of states with different current consumption depending on the operation state even when the hard disk drive is not accessed.
When calculating the load, the load of the hard disk drive is obtained based on the time during which the hard disk drive is accessed and the time during which the hard disk drive is not accessed. The operating state of the hard disk drive when it is not accessed is determined based on the duration that the hard disk drive is not accessed,
A method for calculating a remaining battery level. A program for causing an information terminal driven by a battery to calculate the remaining battery charge,
Detecting a battery voltage which is a voltage of the battery;
Monitoring the load on the battery of the drive unit that is driven by receiving power supply from the battery, and calculating the load according to the operating state of the drive unit;
In calculating the remaining battery level based on the battery voltage, calculating the corrected battery level based on the calculated load;
To the information terminal ,
The drive unit includes a hard disk drive, and the hard disk drive has a plurality of states with different current consumption depending on the operation state even when the hard disk drive is not accessed.
In the step of calculating the load, the load of the hard disk drive is obtained and the hard disk drive is accessed based on the time during which the hard disk drive is accessed and the time during which the hard disk drive is not accessed. The operating state of the hard disk drive when not being determined is determined based on the duration that the hard disk drive is not accessed,
A program characterized by that .

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