JP2006129689A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus calculating power consumption, without particularly providing a measuring means. <P>SOLUTION: A CPU 3 samples and accumulates an ON period of a switching signal given to a switching element S1 from a switching control circuit 2 and reads power consumption stored in a non-volatile memory 4, corresponding to an accumulation period so as to output power consumption. Thus, power consumption can be calculated without arranging the special means, and cost is prevented from becoming high. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic device, and more particularly to an electronic device having a function of measuring power consumption.

Recently, in image forming apparatuses such as laser printers and copying machines, power saving has been demanded, and various devices have been devised. For example, in Japanese Patent Laid-Open No. 7-319317 (Patent Document 1), power consumption is calculated from the voltage applied to the fixing heater and the current flowing through the fixing heater, and the calculated power consumption and the reference power consumption are almost equal. An image forming apparatus having a power saving function that stabilizes the fixing temperature and minimizes power consumption by changing the set temperature of the fixing heater so as to match is described.
JP-A-7-319317 (paragraph numbers 0014 to 0017, FIG. 1)

  In the image forming apparatus described in Patent Document 1, the current flowing through the fixing heater and various loads and the applied voltage are detected by an ammeter and a voltmeter and input to the arithmetic processing unit. The power consumption during sampling is calculated.

  However, the ammeter and the voltmeter are not necessarily functions that are necessary when an image is formed by the image forming apparatus, and providing them increases the cost. The calculation of the power consumption is performed not only in the image forming apparatus but also in general electronic devices.

  Accordingly, an object of the present invention is to provide an electronic apparatus that can calculate power consumption without providing a special measuring means.

  The present invention is an electronic device that converts an input DC voltage into a predetermined power supply voltage by switching control and supplies the same to a load, and a control period calculation means for calculating a control period in the switching power supply means A storage unit that stores a correspondence relationship between the control period and the power consumption corresponding to the control period in advance, and a consumption corresponding to the calculated control period according to the control period calculated by the control period calculation unit. Power consumption calculating means for reading out the power from the storage means and outputting it.

  Preferably, the switching power supply means includes a switching signal generating means for outputting a switching signal and changing a duty ratio of the switching signal according to a load, and a switching element for switching according to the switching signal, and the control period calculating means includes The ON period in the duty ratio of the switching signal is calculated according to the switching signal. As a specific example of calculating the ON period, the ON period in the duty ratio of the switching signal is sampled, and the period in each sampling value is accumulated to calculate the accumulated value of the ON period.

  Preferably, the switching power supply means is a step-down type.

  Preferably, the output means includes display means for displaying power consumption.

  Preferably, the electronic device shifts from the image forming mode to the standby mode after forming an image, and shifts from the standby mode to the power saving mode that minimizes power consumption after a predetermined time has elapsed, thereby forming a new image. The image forming apparatus that shifts from the power saving mode to the start mode for forming an image in response to the request for the image and calculates the power consumption by the power consumption calculation unit in each mode, and the power consumption calculation unit includes: Measuring means for measuring an average image formation request interval when a predetermined number of image formation requests are given, and a power saving mode corresponding to an average image formation request interval in which a preset power saving mode transition time is measured If it is longer than the transition time, a determination means for setting the predetermined time to be short and shifting to the power saving mode is included.

  If the power saving mode transition time that is set in advance is shorter than the power saving mode transition time corresponding to the average image formation request interval that is measured, the determining means reduces the power consumption by shifting from the standby mode to the power saving mode. The predetermined time is extended according to the fact that the power consumption in the startup mode is larger.

  Since the present invention calculates the control period in the switching power supply means and outputs the power consumption corresponding to the calculated control period in response to the calculation of the control period, there is no need to provide any special means. The power consumption can be calculated and the cost is not increased.

  FIG. 1 is a block diagram of a power consumption calculation circuit for an electronic device according to an embodiment of the present invention. In FIG. 1, a switching power supply circuit 1 is a typical step-down switching power supply circuit, and includes a switching control circuit 2 as a switching signal generating means, a switching element S1, an inductor L1, a smoothing capacitor C1, And a commutation diode D1. The switching power supply circuit 1 may be a boost type.

  A DC voltage converted from an AC voltage of a commercial power supply is supplied to the drain of the switching element S1, and a switching signal that changes in a pulse shape is applied from the switching control circuit 2 to the gate of the switching element S1. The source of the switching element S1 is connected to one end of the inductor L1 and the cathode of the commutation diode D1.

  The other end of the inductor L1 serves as a power supply output and is connected to one electrode of the smoothing capacitor C1. The anode of the commutation diode D1 and the other electrode of the smoothing capacitor D1 are grounded. The power output is supplied to the image forming means serving as a load, and is also supplied to the switching control circuit 2 as a feedback signal. The image forming unit serving as a load is, for example, a fixing device that consumes the most power in an electronic device. The switching control circuit 2 determines the state of the load based on the feedback signal and changes the duty ratio between the on period and the off period of the switching signal.

  The switching signal output from the switching control circuit 2 is also given to the CPU 3 as a control period calculation unit and a power consumption calculation unit. The CPU 3 is provided to control the entire electronic device, and is also used as a means for calculating power consumption. The CPU 3 is connected to a non-volatile memory 4 as storage means and a display device 5 as display means. The nonvolatile memory 4 stores, as table data, the relationship between the duty ratio between the on period and the off period, which is the control period of the switching signal, and the corresponding power consumption.

  FIG. 2 is a waveform diagram for explaining the operation of the switching power supply circuit shown in FIG. 1, and FIG. 3 is a flowchart showing the operation for calculating power consumption by the CPU shown in FIG.

  Next, the power consumption calculation operation in the electronic device according to the embodiment of the present invention will be described. When the switching signal is supplied from the switching control circuit 2 to the switching element S1, the switching element S1 is turned on only during the period when the switching signal is at the “H” level. When the switching element S1 is turned on, energy is accumulated in the inductor L1 by the input DC voltage, and the smoothing capacitor C1 is charged, and this charging voltage is supplied to the load as a DC power supply output. This DC power output is fed back to the switching control circuit 2.

  The switching control circuit 2 compares the DC power supply output with the reference voltage indicated by the dotted line in FIG. 2B, and when the DC power supply output exceeds the reference voltage, the switching signal shown in FIG. The switching element S1 is turned off. When the switching element S1 is turned off, the current supplied to the inductor L1 is cut off, but the energy accumulated in the inductor L1 is released, and the current flows to the smoothing capacitor C1 through the path of the smoothing capacitor C1 and the commutation diode D1. Flows to charge the smoothing capacitor C1, and this charging voltage is supplied to the load as a DC power supply output.

  When the switching element S1 continues to be turned off, the DC power output fed back to the switching control circuit 2 decreases as the current is consumed by the load and falls below the reference voltage. ”Level to turn on the switching element S1. By repeating this operation, the switching control circuit 2 changes the duty ratio between the ON period and the OFF period of the switching signal, and the DC power supply output dropped to a constant voltage is supplied to the load.

  On the other hand, since the switching signal is given to the CPU 3 from the switching control circuit 2, it is determined whether or not the switching control signal is turned on in step SP1 (abbreviated as SP in the drawing) SP1 shown in FIG. Since the period during which the switching signal output from the switching control circuit 2 is turned on varies depending on the current consumption on the load side, when determining that the switching signal is on, the CPU 3 samples the period during which the switching signal is turned on in step SP2. In step SP3, the sampled on periods are integrated to calculate a cumulative value of the on periods.

  Since the nonvolatile memory 4 stores in advance table data of the correspondence between the duty ratio between the ON period and the OFF period of the switching signal and the power consumption necessary for the CPU 3 to calculate the power consumption, the CPU 3 In step SP4, the power consumption corresponding to the accumulated value of the sampled ON period is calculated based on the table data, and the calculated power consumption is displayed on the display device 5 in step SP5.

  By displaying the power consumption on the display device 5 in this way, it is possible to appeal power saving to the user. It is also possible to use the time for energizing the electronic device due to the power consumption and the calculation of the power charge. Further, when the energized time is shorter than the service life at the time of recycling, it can be used for selecting as a usable part.

  Further, by continuously recording the usage status and power consumption of the electronic device as data, the control settings can be changed so that the power saving effect can be optimally controlled according to the usage status of the user. Such an embodiment is described below.

  FIG. 4 is a diagram showing a relationship between an operation mode and power consumption of an image forming apparatus as an example of an electronic apparatus according to an embodiment of the present invention. The horizontal axis indicates the operation time of the image forming apparatus, and the vertical axis indicates unit time. Per unit of power consumption.

  In FIG. 4, the arrow indicates the timing of the image formation request when the user requested the image formation, and (A) shows the case where the time for shifting to the power saving mode is longer than the average image formation request interval. (B) shows a case where the time for shifting to the power saving mode is shorter than the average image formation request interval.

  Image forming operation modes in electronic devices include startup, printing, standby, and power saving modes. The activation mode is a mode in which the electronic device is activated from the power saving mode, and is a section in which the electronic device is warmed up to a necessary state in order to perform processing requested by the user, and power consumption in each mode is maximized. .

  The print mode indicates an operation section that provides a print process requested by the user. In the standby mode, processing can be started immediately for a new processing request. In the power saving mode, a user's processing request can be accepted, but the processing cannot be started unless the mode is temporarily shifted to the activation mode. In this power saving mode, power consumption during each mode is minimized. It is set to shift to the power saving mode when a predetermined time elapses in the standby mode.

  The continuation time of the standby mode from the end of the printing process to the transition to the power saving mode is set to be a predetermined time as described above, but the optimum state varies depending on each use environment. . For this reason, it is desirable that power consumption can be automatically optimized in an actual usage environment.

  In the case of FIG. 4A, since it takes a long time to shift to the power saving mode, the accumulated power in the shaded portion is wasted because the standby state continues even when the next image formation request is not generated. Yes. Therefore, in this embodiment, the total amount of power can be suppressed by controlling the transition time to the power saving mode to be short.

  In the case of FIG. 4B, since the time for shifting to the power saving mode is short, the state has been shifted to the power saving mode in most cases until the next image formation request is generated. become. For this reason, it is necessary to shift to the start mode after shifting to the start mode until the print process is ready, and the power consumption becomes larger than when the standby mode is maintained.

  Therefore, in this embodiment, if the integrated power in the startup mode indicated by diagonal lines is larger than the integrated power indicated by the checkered pattern generated by extending the transition time to the power saving mode, the time for shifting to the power saving mode is extended. The total power can be suppressed by controlling so as to.

  FIG. 5 is a flowchart for explaining the operation of shifting to each mode shown in FIGS. 4 (A) and 4 (B). The processing based on this flowchart is performed by the CPU 1 shown in FIG. For this reason, an image formation request signal (not shown) is given to the CPU 1 every time there is an image formation request for forming an image.

  In step SP11, the CPU 1 determines the time interval between image formation requests every time an image formation request signal is given. When a new image formation request signal is given, in step SP12, FIG. It is determined whether or not the currently set power saving mode transition time is shorter than the power saving mode transition time at the time of the average image formation request. Here, the average image formation request interval is, for example, a value obtained by averaging the time of the image request intervals every time a predetermined number of image formation requests are given. Step SP11 constitutes a measuring means, and step SP12 constitutes a judging means.

  When it is determined that the currently set power saving mode transition time is shorter than the power saving mode transition time at the time of the average image formation request, that is, when the example shown in FIG. In FIG. 4B, the integrated power in the start mode (indicated by the diagonal lines in FIG. 4B) is greater than the integrated power (indicated by the checkered pattern in FIG. 4B) of the increase caused by extending the transition time to the power saving mode. Confirm that the part shown) is large. In step SP14, the time for shifting to the power saving mode is extended.

  In step SP12, when it is determined that the currently set power saving mode transition time shown in FIG. 4A is longer than the power saving mode transition time at the time of the average image formation request, that is, FIG. 4A. If this is the case, the time for shifting from the standby mode to the power saving mode is corrected to be shorter in step SP15.

  Through this series of processing, the total amount of power in the electronic device can be suppressed.

  In the above description, the example in which the present invention is applied to the image forming apparatus has been described.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

It is a block diagram of the principal part of the electronic device in one Embodiment of this invention. FIG. 2 is a waveform diagram for explaining the operation of the switching power supply circuit shown in FIG. 1. 3 is a flowchart illustrating an operation for calculating power consumption by a CPU illustrated in FIG. 1. It is a figure which shows the relationship between the operation mode of an electronic device and power consumption in one Embodiment of this invention. 5 is a flowchart for explaining an operation of shifting to each mode shown in FIG. 4.

Explanation of symbols

  1 switching power supply circuit, 2 switching control circuit, 3 CPU, 4 nonvolatile memory, 5 display device, S1 switching element, L1 inductor, D1 commutation diode, C1 smoothing capacitor.

Claims (7)

Switching power supply means for converting the input DC voltage into a predetermined power supply voltage by switching control and supplying the voltage to a load;
Control period calculation means for calculating a control period in the switching power supply means;
Storage means for storing in advance a correspondence relationship between the control period and power consumption corresponding to the control period;
An electronic apparatus comprising: a power consumption calculation unit that reads out and outputs power consumption corresponding to the calculated control period from the storage unit in response to the control period being calculated by the control period calculation unit. The switching power supply means is
Switching signal generating means for outputting a switching signal and changing a duty ratio of the switching signal according to the load;
A switching element that switches according to the switching signal,
The electronic device according to claim 1, wherein the control period calculation unit calculates an ON period in a duty ratio of the switching signal according to the switching signal.   The electronic device according to claim 2, wherein the control period calculation unit samples an ON period in a duty ratio of the switching signal, and calculates a cumulative value of the ON period by accumulating periods in respective sampling values.   The electronic device according to claim 1, wherein the switching power supply unit is a step-down type. Furthermore, the display means for displaying the power consumption,
The electronic device according to claim 1, wherein the power consumption calculation unit displays the power consumption on the display unit. After the image is formed, the electronic device shifts from the image formation mode to the standby mode, and after a predetermined time has passed, the electronic device shifts to the power saving mode that minimizes the power consumption, and a new image formation request is given. The image forming apparatus that shifts from the power saving mode to an activation mode for forming an image according to the situation and calculates the power consumption by the power consumption calculation unit in each mode,
The power consumption calculating means includes
A measuring means for measuring an average image formation request interval when a predetermined number of image formation requests are given;
A determination unit configured to set the predetermined time short and shift to the power saving mode if the preset power saving mode transition time is longer than the power saving mode transition time corresponding to the measured average image formation request interval; The electronic device according to claim 1, comprising:   If the predetermined power saving mode transition time is shorter than the power saving mode transition time corresponding to the measured average image formation request interval, the determination means shifts from the standby mode to the power saving mode. The electronic device according to claim 6, wherein the predetermined time is extended according to the fact that the power consumption in the startup mode is larger than the power consumption.

Images