JP2005352672A - Electric equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electric equipment capable of reducing a processing burden on a central processing unit, and performing heat radiation control or power saving control of the central processing unit. <P>SOLUTION: A counter 215 of an LSI 2 measures an operation time wherein a CPU 1 is operated in a normal state wherein the power saving control is not performed, a CPU power saving control time count part 211 measures a power saving control time wherein the CPU 1 is power-saving-controlled, a CPU operating rate calculation part 212 calculates a ratio of the operation time to a total time of the operation time measured by the counter 215 and the power saving control time measured by the CPU power saving control time count part 211 as an operating rate of the CPU 1, and an event generation part 213 generates an event instructing at least one of the power saving control of the CPU 1 and the heat radiation control for radiating heat of the CPU 1 according to the operating rate calculated by the CPU operating rate calculation part 212. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electric device that performs power saving control of a central processing unit and an electric device that performs power saving control of an integrated circuit connected to the central processing unit.

Conventionally, as one of the power saving methods for saving power of a CPU (Central Processing Unit), for example, there is a technique described in Patent Document 1. In the power saving method of Patent Document 1, the CPU operating frequency is switched according to the operation rate based on the processing amount processed inside the CPU, and the frequency switching is performed in order to realize the optimum frequency at that time. The optimum power saving control is realized by monitoring the frequency.
Japanese Patent No. 2766170

  However, in the conventional method, the operating rate cannot be monitored unless the CPU is in a normal state where power saving control is not performed, and CPU resources are used to count job time and calculate the operating rate. Had to do. Therefore, the conventional method has a problem that the CPU resources increase.

  In recent years, when the entire system performs power saving control, the CPU may have to perform processing after returning from the power saving control state to the normal state. That is, it is difficult to use the conventional method when performing power saving control of a CPU that operates in a short time, or when it is desired to perform heat dissipation control even when the CPU is controlled to save power at regular intervals.

  The present invention has been made to solve the above problems, and provides an electric device that can reduce the processing load of the central processing unit and can perform power saving control or heat dissipation control of the central processing unit. It is for the purpose.

  An electrical device according to the present invention is an electrical device that performs power saving control of a central processing unit, and an integrated circuit connected to the central processing unit is not subjected to power saving control by the central processing unit Device operating time measuring means for measuring operating time operated in a normal state, device power saving control time measuring means for measuring power saving control time during which the central processing unit is subjected to power saving control, and device operating The ratio of the operating time to the total time of the operating time measured by the time measuring unit and the power saving control time measured by the device power saving control time measuring unit is calculated as the operating rate of the central processing unit. An apparatus operating rate calculating unit that performs power saving control of the central processing unit and the central processing unit according to the operating rate calculated by the apparatus operating rate calculating unit. Of heat radiating control and a device instruction means for instructing at least one.

  According to this configuration, in the integrated circuit connected to the central processing unit, the operation time during which the central processing unit is operated in a normal state where power saving control is not performed is measured, and the central processing unit is configured to save power. The controlled power saving control time is measured, and the ratio of the operating time to the total time of the measured operating time and the measured power saving control time is calculated as the operating rate of the central processing unit. Then, at least one of power saving control and heat dissipation control for radiating heat from the central processing unit is instructed to the central processing unit according to the calculated operation rate.

  As described above, since the operation rate of the central processing unit is calculated by an integrated circuit connected to the central processing unit, not the central processing unit, the processing load on the central processing unit is reduced and the central processing unit is reduced. Power saving control or heat dissipation control of the apparatus can be performed.

  Further, in the above-described electrical apparatus, when the operating rate calculated by the device operating rate calculating unit reaches a preset interrupt reference value, an interrupt generating unit that generates an interrupt to the central processing unit is further provided. It is preferable to provide.

  According to this configuration, when the operating rate of the central processing unit reaches a preset interrupt reference value, an interrupt to the central processing unit is generated, so according to the operating rate of the central processing unit Interrupt processing can be performed on the central processing unit.

  Further, in the above-described electrical apparatus, the device instruction means may perform heat dissipation control for radiating heat from the central processing unit when the operating rate calculated by the device operating rate calculating unit reaches a preset heat dissipation reference value. Is preferably indicated.

  According to this configuration, when the operation rate of the central processing unit reaches a preset heat dissipation reference value, heat dissipation control for dissipating heat from the central processing unit is instructed, so the operation rate of the central processing unit is Accordingly, heat dissipation control can be performed on the central processing unit.

  In the above-described electrical apparatus, the apparatus further includes a power saving control unit that receives a power saving control request from the central processing unit and outputs a power saving control permission signal to the device power saving control time measuring unit and the central processing unit. The apparatus power saving control time measuring means starts measuring the power saving control time during which the central processing unit is subjected to power saving control when a power saving control permission signal is input from the power saving control means. The central processing unit executes power saving control when the power saving control permission signal is input from the power saving control means, and the device operating rate calculation means is measured by the device power saving control time measuring means. By dividing the operating time by the total time of the measured power saving control time and the operating time measured by the device operating time measuring means, When the operating rate calculated by the device operating rate calculating unit exceeds a preset threshold value, the device instructing unit determines power saving control of the central processing unit and the central processing unit. It is preferable to indicate at least one of the heat dissipation controls for dissipating heat.

  According to this configuration, in response to the power saving control request from the central processing unit, the power saving control permission signal is output to the device power saving control time measuring means and the central processing unit, and the power saving control permission signal is transmitted to the device power saving control. When input to the time measurement means, measurement of the power saving control time when the central processing unit is controlled to save power is started, and when the power saving control permission signal is input to the central processing unit, power saving control is performed. Executed. The operating rate of the central processing unit is obtained by dividing the operating time by the total time of the power saving control time measured by the device power saving control time measuring unit and the operating time measured by the device operating time measuring unit. When the calculated operation rate exceeds the preset threshold, at least one of the power saving control of the central processing unit and the heat dissipation control for radiating heat from the central processing unit is instructed.

  Therefore, in response to the power saving control request from the central processing unit, the power saving control permission signal is output to the device power saving control time measuring means and the central processing unit, and when the power saving control permission signal is input, the central processing Since the power saving control is started in the processing device, and the power saving control time measurement in which the central processing device is controlled is started, the central processing is performed in the integrated circuit connected to the central processing device. The time during which the power saving control of the apparatus is performed can be accurately measured.

  Further, in the above electrical equipment, circuit operating time measuring means for measuring an operating time in which the integrated circuit connected to the central processing unit is operated in a normal state where power saving control is not performed, and the integrated circuit includes The circuit power saving control time measuring means for measuring the power saving control time being controlled, the operating time measured by the circuit operating time measuring means, and the circuit power saving control time measuring means measured by the circuit power saving control time measuring means A circuit operation rate calculation unit that calculates a ratio of the operation time to a total time with a power saving control time as an operation rate of the integrated circuit, and the integrated circuit according to the operation rate calculated by the circuit operation rate calculation unit. It is preferable to further include circuit instruction means for instructing at least one of power saving control and heat dissipation control for radiating heat from the integrated circuit.

  According to this configuration, the power saving control time during which the integrated circuit connected to the central processing unit is operated in a normal state where the power saving control is not performed is measured and the integrated circuit is subjected to the power saving control. Is measured, and the ratio of the operating time to the total time of the measured operating time and the measured power saving control time is calculated as the operating rate of the integrated circuit. Then, at least one of power saving control and heat dissipation control for radiating heat from the integrated circuit is instructed to the integrated circuit according to the calculated operation rate.

  As described above, since the operation rate of the integrated circuit connected to the central processing unit is calculated by the integrated circuit, not the central processing unit, the processing load of the central processing unit can be reduced. In addition to performing power saving control or heat dissipation control of the processing apparatus, it is possible to perform power saving control or heat dissipation control of the integrated circuit.

  Further, an electrical device according to the present invention is an electrical device that performs power saving control of an integrated circuit connected to a central processing unit, and the integrated circuit is a normal device that does not perform power saving control. A circuit operating time measuring means for measuring an operating time operated in a state; a circuit power saving control time measuring means for measuring a power saving control time during which the integrated circuit is controlled to save power; and the circuit operating time measuring means. Circuit operation rate calculation means for calculating a ratio of the operation time to the total time of the measured operation time and the power saving control time measured by the circuit power saving control time measurement means as the operation rate of the integrated circuit And at least one of power saving control for the integrated circuit and heat dissipation control for radiating heat from the integrated circuit according to the operating rate calculated by the circuit operating rate calculating means. And a circuit indicating means for.

  According to this configuration, in the integrated circuit connected to the central processing unit, the operation time during which the integrated circuit is operated in a normal state where the power saving control is not performed is measured, and the power saving control is performed on the integrated circuit. The power saving control time is measured, and the ratio of the operating time to the total time of the measured operating time and the measured power saving control time is calculated as the operating rate of the integrated circuit. Then, at least one of power saving control and heat dissipation control for radiating heat from the integrated circuit is instructed to the integrated circuit according to the calculated operation rate.

  As described above, since the operation rate of the integrated circuit connected to the central processing unit is calculated by the integrated circuit, not the central processing unit, the processing load of the central processing unit is reduced and the integrated circuit is saved. Power control or heat dissipation control can be performed.

  According to the present invention, the operating rate of the central processing unit is calculated by an integrated circuit connected to the central processing unit instead of the central processing unit. Power saving control or heat dissipation control of the arithmetic processing unit can be performed.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. The present invention can be applied to all electric devices that perform power saving control or heat dissipation control. However, in the following description, an image forming apparatus such as a copying machine, a printer device, a facsimile device, and a printing machine is used as an electric device. This will be described as an example.

(First embodiment)
FIG. 1 is a block diagram illustrating an electrical configuration of the image forming apparatus according to the first embodiment. The image forming apparatus shown in FIG. 1 has a CPU (Central Processing Unit) 1 that operates a computer, an LSI (Large Scale Integration) 2 connected to the CPU 1, and CPU cooling that cools the CPU 1. It is provided with a fan 3.

  The CPU 1 can be divided into a software layer (abbreviated as a software layer in FIG. 1) 11 controlled by software and a hardware layer (abbreviated as a hardware layer in FIG. 1) 12 controlled by hardware. The hardware layer 12 includes a power saving start control unit 121, a CPU power saving control unit 122, a system clock unit 123, and an interrupt determination unit 124.

  The software layer 11 notifies the power saving start control unit 121 that power saving control is to be executed. Further, the software layer 11 receives an interrupt from the interrupt determination unit 124 and executes predetermined processing, for example, processing for notifying the power saving start control unit 121 that power saving control is to be executed.

  The power saving start control unit 121 receives the power saving control execution notification notified from the software layer 11, and sends a power saving control request signal for requesting power saving control to the CPU power saving control unit 122, the power saving control unit 22, The data is output to the CPU power saving control time counting unit 211.

  If the power saving control request signal input from the power saving start control unit 121 and the power saving control permission signal input from the power saving control unit 22 are both asserted, the CPU power saving control unit 122 determines that the CPU 1 The power saving control is performed using the power saving function. The power saving function is, for example, a function of shutting down an unnecessary power source used by the board included in the CPU 1.

  The system clock unit 123 inputs the system clock generated by the system clock generation unit 23. When an interrupt signal is input from the interrupt control unit 24, the interrupt determination unit 124 determines whether or not the interrupt signal is an interrupt request, and if it is an interrupt request, instructs the software layer 11 to perform interrupt control.

  The LSI 2 is a chip set connected to the CPU 1 and includes a CPU operating rate calculation unit 21, a power saving control unit 22, a system clock generation unit 23, an interrupt control unit 24, and a heat dissipation control unit 25.

  The CPU operating rate calculating unit 21 includes a CPU power saving control time counting unit 211, a CPU operating rate calculating unit 212, an event generating unit 213, an operation setting register 214, a counter 215, and a frequency divider 216.

  The CPU power saving control time counting unit 211 determines whether the power saving control request signal input from the power saving start control unit 121 and the power saving control permission signal input from the power saving control unit 22 are both asserted. The time during which power saving control is performed is counted using the sampling clock input from the frequency divider 216. When the counter is reset by the counter 215, the CPU power saving control time count unit 211 outputs the count time of the power saving control time from the start of counting to the reset to the CPU operating rate calculation unit 212.

  The CPU operating rate calculation unit 212 uses the power saving control time input from the CPU power saving control time counting unit 211 and the count time (CPU operating time + power saving control time) input from the counter 215 to operate the CPU. Calculate the rate. The CPU operating rate calculation unit 212 acquires an event occurrence threshold for the CPU operating rate from the operation setting register 214, determines whether or not the calculated operating rate exceeds the acquired threshold, and the threshold determination that is the result The value is output to the event generation unit 213.

  The event generation unit 213 acquires the event type corresponding to the threshold determination result from the operation setting register 214, selects the event type corresponding to the threshold determination value input from the CPU operating rate calculation unit 212, and selects the selected event Depending on the type, the execution instruction to the power saving control unit 22, the interrupt control unit 24, and the heat dissipation control unit 25 is performed. The event generation unit 213 generates an event by accessing from another interface (I / F) connected to the LSI 2. At this time, when the event generated by the event generation unit 213 is an event for stopping the power saving control of the CPU 1, the power saving control unit 22 does not permit the CPU power saving control unit 122 to perform the power saving control. Outputs a control permission signal.

  The operation setting register 214 stores predetermined setting values of the CPU operation rate calculation unit 212, the event generation unit 213, the counter 215, and the frequency divider 216 set by the software layer 11 of the CPU 1 via the CPU bus. The setting value of the CPU operation rate calculation unit 212 is a threshold value of event occurrence with respect to the operation rate of the CPU 1, the setting value of the event generation unit 213 is an event type for the result of the threshold determination, and the setting value of the counter 215 is It is a sampling reset period, and the set value of the frequency divider 216 is a sampling unit of CPU operating time.

  The counter 215 obtains the sampling reset period from the operation setting register 214, counts the time using the sampling clock input from the frequency divider 216, and outputs the count time to the CPU operating rate calculation unit 212. When the counter 215 counts up to the acquired sampling reset period, the counter 215 and the CPU power saving control time counting unit 211 are reset.

  The frequency divider 216 acquires the sampling unit of the CPU operating time from the operation setting register 214 and receives the system clock generated by the system clock generation unit 23, and divides the frequency according to the acquired sampling unit of the CPU operating time. The system clock is divided by the rate to generate a sampling clock, and the generated sampling clock is output to the counter 215 and the CPU power saving control time counting unit 211.

  When an event is generated by the event generation unit 213 (when an execution instruction is input from the event generation unit 213), the power saving control unit 22 includes a CPU power saving control unit 122, a CPU power saving control time counting unit 211, Outputs a power saving control permission signal for permitting power saving control.

  The system clock generator 23 generates a system clock. The interrupt control unit 24 outputs an interrupt signal to the interrupt determination unit 124 when an event is generated by the event generation unit 213 (when an execution instruction is input from the event generation unit 213).

  The heat dissipation control unit 25 outputs a fan control signal to the CPU cooling fan 3 when an event is generated by the event generation unit 213 (when an execution instruction is input from the event generation unit 213).

  The CPU cooling fan 3 controls on / off of the fan by a fan control signal input from the heat dissipation control unit 25.

  In this embodiment, a part of the counter 215 and the CPU operation rate calculation unit 212 corresponds to an example of an apparatus operation time measurement unit, and the CPU power saving control time count unit 211 corresponds to an example of an apparatus power saving control time measurement unit. The CPU operation rate calculation unit 212 corresponds to an example of a device operation rate calculation unit, the event generation unit 213 corresponds to an example of a device instruction unit, and the power saving control unit 22 corresponds to an example of a power saving control unit. .

  Next, power saving / heat radiation control processing of the image forming apparatus according to the first embodiment will be described.

  First, the power saving start control unit 121 receives a power saving control execution notification notified from the software layer 11, and sends a power saving control request signal for requesting power saving control to the CPU power saving control unit 122 and the power saving control unit. 22 and the CPU power saving control time counting unit 211. When the power saving control request signal is input and the execution instruction from the event generating unit 213 is not input, the power saving control unit 22 saves the CPU power saving control unit 122 and the CPU power saving control time counting unit 211. A power saving control permission signal for permitting power control is output.

  If the power saving control request signal input from the power saving start control unit 121 and the power saving control permission signal input from the power saving control unit 22 are both asserted, the CPU power saving control unit 122 determines that the CPU 1 The power saving control is performed using the power saving function.

  The frequency divider 216 obtains the sampling unit of the CPU operating time from the operation setting register 214 and receives the system clock generated by the system clock generation unit 23 and matches the acquired sampling unit of the CPU operating time. The system clock is divided by the division ratio to generate a sampling clock, and the generated sampling clock is output to the counter 215 and the CPU power saving control time count unit 211.

  The sampling clock output from the frequency divider 216 is input to the counter 215 and the CPU power saving control time count unit 211. The counter 215 obtains the sampling reset period from the operation setting register 214, counts the total time of CPU operation time and power saving control time using the sampling clock input from the frequency divider 216, and counts the CPU The total time of the operation time and the power saving control time is output to the CPU operation rate calculation unit 212. Then, when the counter 215 counts the time until the acquired sampling reset period, the counter 215 and the CPU power saving control time counting unit 211 are reset.

  On the other hand, the CPU power saving control time count unit 211 asserts both the power saving control request signal input from the power saving start control unit 121 and the power saving control permission signal input from the power saving control unit 22. The power saving control time during which the power saving control is performed is counted using the sampling clock input from the frequency divider 216. Then, when the counter is reset by the counter 215, the CPU power saving control time count unit 211 outputs the count time of the power saving control time from the start of counting until the reset to the CPU operating rate calculation unit 212. .

The CPU operating rate calculation unit 212 uses the power saving control time input from the CPU power saving control time counting unit 211 and the CPU operating time and the total time of the power saving control time input from the counter 215. Is calculated. Specifically, the CPU operating rate calculation unit 212 subtracts the power saving control time input from the CPU power saving control time counting unit 211 from the total time of the CPU operating time and the power saving control time input from the counter 215. Thus, the CPU operating time is calculated. Then, as shown in the following equation (1), the CPU operating rate calculation unit 212 is a value obtained by adding the power saving time and the CPU operating time, that is, the CPU operating time and the power saving control time input from the counter 215. The CPU operating rate is calculated by dividing the calculated CPU operating time by the total time.
CPU operating rate = CPU operating time / (power saving control time + CPU operating time) (1)

  Then, the CPU operating rate calculation unit 212 acquires the event occurrence threshold for the operating rate of the CPU 1 from the operation setting register 214, determines whether or not the calculated operating rate exceeds the acquired threshold, and is the result. The threshold judgment value is output to the event generation unit 213. For example, if the calculated operating rate exceeds the acquired threshold, the CPU operating rate calculating unit 212 outputs the threshold judgment value as “1” to the event generating unit 213, and the calculated operating rate exceeds the acquired threshold. If not, the threshold judgment value is output to the event generation unit 213 as “0”.

  The event generation unit 213 acquires the event type corresponding to the threshold determination result from the operation setting register 214, selects the event type corresponding to the threshold determination value input from the CPU operating rate calculation unit 212, and selects the selected event Depending on the type, the execution instruction to the power saving control unit 22, the interrupt control unit 24, and the heat dissipation control unit 25 is performed. For example, when the threshold judgment value input from the CPU operating rate calculation unit 212 is “1” (when the calculated operating rate exceeds the acquired threshold), the event for starting the heat dissipation control of the CPU 1 is selected, An execution instruction is given to the heat dissipation control unit 25. For example, when the threshold judgment value input from the CPU operating rate calculation unit 212 is “0” (when the calculated operating rate does not exceed the acquired threshold), an event for starting the power saving control of the CPU 1 is performed. Select and execute an execution instruction to the interrupt control unit 24. In this case, the interrupt control unit 24 requests the interrupt determination unit 124 to interrupt power saving control.

  Here, when the execution instruction from the event generation unit 213 is output to the power saving control unit 22, the power saving control unit 22 saves power to the CPU power saving control unit 122 and the CPU power saving control time count unit 211. A power saving control permission signal for permitting control is output.

  When the execution instruction from the event generation unit 213 is output to the heat dissipation control unit 25, the heat dissipation control unit 25 outputs a fan control signal to the CPU cooling fan 3. The CPU cooling fan 3 controls the fan on / off by a fan control signal input from the heat dissipation control unit 25.

  When the execution instruction from the event generation unit 213 is output to the interrupt control unit 24, the interrupt control unit 24 outputs an interrupt signal to the interrupt determination unit 124. Then, when an interrupt signal is input from the interrupt control unit 24, the interrupt determination unit 124 determines whether the interrupt signal is an interrupt request, and if it is an interrupt request, instructs the software layer 11 to interrupt. . Then, the software layer 11 notifies the power saving start control unit 121 that power saving control is to be executed.

  As described above, in the LSI 2 connected to the CPU 1, the operation time during which the CPU 1 is operated in a normal state where the power saving control is not performed is measured, and the power saving control time during which the CPU 1 is controlled to save power is measured. The ratio of the operating time to the total time of the measured operating time and the measured power saving control time is calculated as the operating rate of the CPU 1. Then, at least one of the power saving control of the CPU 1 and the heat dissipation control for radiating the CPU 1 is instructed according to the calculated operation rate.

  Therefore, since the operating rate of the CPU 1 is calculated not by the CPU 1 but by the LSI 2 connected to the CPU 1, it is possible to reduce the processing load on the CPU 1 and perform power saving control or heat dissipation control of the CPU 1. In addition, since the calculation of the operating rate of the CPU 1 is performed inside the LSI 2, the calculation inside the CPU 1 is not necessary, so that software resources can be reduced and power saving control is performed even when the CPU 1 performs other processing. be able to. Furthermore, the execution timing of power saving control and heat dissipation control is controlled by the hardware side, so the software side does not require detailed calculations and processing with simple settings, and the hardware is complicated by software. It can be realized with a simple and minimal configuration.

  Further, when the operating rate of the CPU 1 reaches a preset threshold value (interrupt reference value), an interrupt to the CPU 1 is generated, and when the interrupt occurs, the CPU 1 outputs a power saving control request to the LSI 2. Depending on the operating rate of the CPU 1, interrupt processing can be performed on the CPU 1, and the processing of the CPU 1 can be reduced. Further, when the operating rate of the CPU 1 reaches a preset threshold value (power saving reference value), power saving control of the CPU 1 is instructed, so that power saving control is performed on the CPU 1 according to the operating rate of the CPU 1. It can be performed. Further, when the operating rate of the CPU 1 reaches a preset threshold value (heat dissipation reference value), the heat dissipation control for dissipating the CPU 1 is instructed. It can be carried out.

  Furthermore, when a power saving control request is input from the CPU 1, a power saving control permission signal is output to the CPU power saving control time counting unit 211 and the CPU 1, and the power saving control permission signal is sent to the CPU power saving control time counting unit 211. When input, the measurement of the power saving control time during which the CPU 1 is under power saving control is started. When the power saving control permission signal is input to the CPU 1, the power saving control is executed. Then, the operating rate of the CPU 1 is calculated by dividing the operating time by the total time of the power saving control time measured by the CPU power saving control time counting unit 211 and the operating time measured by the counter 215. When the operating rate exceeds a preset threshold value (heat dissipation reference value), at least one of the power saving control of the CPU 1 and the heat dissipation control of radiating the CPU 1 is instructed.

  Therefore, in response to the power saving control request from the CPU 1, the power saving control permission signal is output to the CPU power saving control time count unit 211 and the CPU 1, and when the power saving control permission signal is input, the CPU 1 starts the power saving control. In addition, since the measurement of the power saving control time during which the CPU 1 is controlled to save power is started, the time during which the power saving control of the CPU 1 is performed can be accurately measured in the LSI 2 connected to the CPU 1.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the processing load on the CPU 1 is reduced by calculating the operating rate of the CPU 1 by the LSI 2 connected to the CPU 1. On the other hand, in the second embodiment, the operating rate of the LSI 2 connected to the CPU 1 is calculated, the power saving control and the heat dissipation control of the LSI 2 are performed, and these processes are performed by the LSI 2 instead of the CPU 1. Similar to the first embodiment, the processing load on the CPU 1 is reduced.

  FIG. 2 is a block diagram illustrating an electrical configuration of the image forming apparatus according to the second embodiment. In the following description, the same components as those in the image forming apparatus according to the first embodiment shown in FIG. Therefore, in the following description, only a configuration different from the first embodiment will be described.

  The image forming apparatus shown in FIG. 2 includes an CPU 1, an LSI 2, and an LSI cooling fan 4 that cools the LSI 2.

  The LSI 2 is a chip set connected to the CPU 1 and includes an LSI operating rate calculation unit 31, a power saving control unit 22 ', a system clock generation unit 23, an interrupt control unit 24, and a heat dissipation control unit 25'.

  The LSI operation rate calculation unit 31 includes an LSI power saving control time count unit 311, an LSI operation rate calculation unit 312, an event generation unit 313, an operation setting register 314, a counter 315, and a frequency divider 316.

  The LSI power saving control time count unit 311 performs power saving control using the sampling clock input from the frequency divider 216 if the power saving control permission signal input from the power saving control unit 22 ′ is asserted. Count time. When the counter 315 resets the count, the LSI power saving control time count unit 311 outputs the count time of the power saving control time from the start of counting to the reset to the LSI operating rate calculation unit 312.

  The LSI operating rate calculation unit 312 uses the power saving control time input from the LSI power saving control time counting unit 311 and the count time (LSI operating time + power saving control time) input from the counter 315 to operate the LSI. Calculate the rate. The LSI operating rate calculation unit 312 acquires an event occurrence threshold for the operating rate of the LSI from the operation setting register 314, determines whether or not the calculated operating rate exceeds the acquired threshold, and the threshold determination that is the result The value is output to the event generation unit 313.

  The event generation unit 313 acquires the event type corresponding to the threshold determination result from the operation setting register 314, selects the event type corresponding to the threshold determination value input from the LSI operating rate calculation unit 312, and selects the selected event Depending on the type, the execution instruction to the power saving control unit 22 ′, the interrupt control unit 24 and the heat radiation control unit 25 is performed. The event generation unit 313 generates an event by access from another interface (I / F) connected to the LSI 2. At this time, if the event generated by the event generation unit 313 is an event for stopping the power saving control of the LSI 2, the power saving control unit 22 ′ does not permit the LSI power saving control time counting unit 311 to perform the power saving control. Outputs a power saving control permission signal.

  The operation setting register 314 stores predetermined setting values of the LSI operation rate calculation unit 312, the event generation unit 313, the counter 315, and the frequency divider 316 set by the software layer 11 of the CPU 1 via the CPU bus. The setting value of the LSI operation rate calculation unit 312 is a threshold value for event occurrence with respect to the operation rate of the LSI 2, the setting value of the event generation unit 313 is the type of event for the result of threshold determination, and the setting value of the counter 315 is It is a sampling reset period, and the set value of the frequency divider 316 is a sampling unit of LSI operating time.

  The counter 315 obtains the sampling reset period from the operation setting register 314, counts the time using the sampling clock input from the frequency divider 316, and outputs the count time to the LSI operating rate calculation unit 312. When the counter 315 counts up to the acquired sampling reset period, the counter 315 and the LSI power saving control time counting unit 311 are reset.

  The frequency divider 316 acquires the sampling unit of the LSI operating time from the operation setting register 314 and receives the system clock generated by the system clock generation unit 23, and divides the frequency according to the acquired sampling unit of the LSI operating time. The system clock is divided by the rate to generate a sampling clock, and the generated sampling clock is output to the counter 315 and the LSI power saving control time count unit 311.

  When an event is generated by the event generation unit 313 (when an execution instruction is input from the event generation unit 313), the power saving control unit 22 ′ permits the LSI power saving control time counting unit 311 to perform power saving control. Outputs a power control permission signal.

  The heat dissipation control unit 25 ′ outputs a fan control signal to the LSI cooling fan 4 when an event is generated by the event generation unit 313 (when an execution instruction is input from the event generation unit 313).

  The LSI cooling fan 4 controls on / off of the fan by a fan control signal input from the heat dissipation control unit 25 ′.

  In the present embodiment, a part of the counter 315 and the LSI operating rate calculation unit 312 corresponds to an example of a circuit operating time measuring unit, and the LSI power saving control time counting unit 311 corresponds to an example of a circuit power saving control time measuring unit. The LSI operation rate calculation unit 312 corresponds to an example of a circuit operation rate calculation unit, and the event generation unit 313 corresponds to an example of a circuit instruction unit.

  Next, power saving / heat radiation control processing of the image forming apparatus according to the second embodiment will be described.

  First, when an instruction to execute power saving control is input from the event generating unit 313, the power saving control unit 22 ′ outputs a power saving control permission signal for permitting power saving control to the LSI power saving control time counting unit 311. .

  The frequency divider 316 acquires the sampling unit of the LSI operating time from the operation setting register 314 and receives the system clock generated by the system clock generation unit 23, and matches the acquired sampling unit of the LSI operating time. The system clock is divided by the division ratio to generate a sampling clock, and the generated sampling clock is output to the counter 315 and the LSI power saving control time count unit 311.

  The sampling clock output from the frequency divider 316 is input to the counter 315 and the LSI power saving control time counting unit 311. The counter 315 obtains the sampling reset period from the operation setting register 314, counts the total time of the LSI operating time and the power saving control time using the sampling clock input from the frequency divider 316, and counts the counted LSI. The total time of the operation time and the power saving control time is output to the LSI operation rate calculation unit 312. The counter 315 resets the counter 315 and the LSI power saving control time counting unit 311 after counting the time until the acquired sampling reset period.

  On the other hand, if the power saving control permission signal input from the power saving control unit 22 is asserted, the LSI power saving control time counting unit 311 performs power saving control using the sampling clock input from the frequency divider 316. The power saving control time is counted. Then, when the count is reset by the counter 315, the LSI power saving control time count unit 311 outputs the count time of the power saving control time from the start of counting until the reset to the LSI operating rate calculation unit 312. .

The LSI operating rate calculation unit 312 uses the power saving control time input from the LSI power saving control time counting unit 311 and the total time of the LSI operating time and the power saving control time input from the counter 315. Is calculated. Specifically, the LSI operating rate calculation unit 312 subtracts the power saving control time input from the LSI power saving control time counting unit 311 from the total time of the LSI operating time and the power saving control time input from the counter 315. As a result, the LSI operating time is calculated. Then, as shown in the following equation (2), the LSI operating rate calculation unit 312 is a value obtained by adding the power saving time and the LSI operating time, that is, the LSI operating time and the power saving control time input from the counter 315. The LSI operation rate is calculated by dividing the calculated LSI operation time by the total time.
LSI operation rate = LSI operation time / (power saving control time + LSI operation time) (2)

  Then, the LSI operating rate calculation unit 312 acquires the event occurrence threshold for the operating rate of the LSI 2 from the operation setting register 314, determines whether the calculated operating rate exceeds the acquired threshold, and the result. The threshold judgment value is output to the event generation unit 313. For example, if the calculated operating rate exceeds the acquired threshold, the LSI operating rate calculating unit 312 outputs the threshold judgment value as “1” to the event generating unit 313, and the calculated operating rate exceeds the acquired threshold. If not, the threshold judgment value is output to the event generation unit 313 as “0”.

  The event generation unit 313 acquires the event type corresponding to the threshold determination result from the operation setting register 314, selects the event type corresponding to the threshold determination value input from the LSI operating rate calculation unit 312, and selects the selected event Depending on the type, the execution instruction is given to the power saving control unit 22 ′, the interrupt control unit 24, and the heat dissipation control unit 25 ′. For example, when the threshold judgment value input from the LSI operating rate calculation unit 312 is “1” (when the calculated operating rate exceeds the acquired threshold), an event for starting the heat dissipation control of the LSI 2 is selected, An execution instruction is given to the heat dissipation control unit 25 ′. For example, when the threshold judgment value input from the LSI operating rate calculation unit 312 is “0” (when the calculated operating rate does not exceed the acquired threshold), an event for starting the power saving control of the LSI 2 is performed. Select and execute an execution instruction to the interrupt control unit 24. In this case, the interrupt control unit 24 requests the interrupt determination unit 124 to interrupt power saving control.

  When the execution instruction from the event generation unit 313 is output to the power saving control unit 22 ′, the power saving control unit 22 ′ outputs a power saving control permission signal for allowing the LSI power saving control time counting unit 311 to perform power saving control. Output.

  When the execution instruction from the event generation unit 313 is output to the heat dissipation control unit 25 ′, the heat dissipation control unit 25 ′ outputs a fan control signal to the LSI cooling fan 4. The LSI cooling fan 4 controls on / off of the fan by a fan control signal input from the heat dissipation control unit 25 ′.

  When the execution instruction from the event generation unit 313 is output to the interrupt control unit 24, the interrupt control unit 24 outputs an interrupt signal to the interrupt determination unit 124. When an interrupt signal is input from the interrupt control unit 24, the interrupt determination unit 124 determines whether or not the interrupt signal is an interrupt request. If the interrupt signal is an interrupt request, the interrupt determination unit 124 instructs the software layer 11 to perform interrupt control. To do.

  In the present embodiment, the LSI power saving control time counting unit 311 may monitor the occurrence of an event by the event generating unit 313 and count the power saving control time of the LSI 2 based on the event occurrence time.

  As described above, in the LSI 2 connected to the CPU 1, the operation time during which the LSI 2 is operated in a normal state where the power saving control is not performed is measured, and the power saving control time during which the LSI 2 is controlled to save power is measured. The ratio of the operation time to the total time of the measured operation time and the measured power saving control time is calculated as the operation rate of the LSI 2. Then, at least one of the power saving control of the LSI 2 and the heat dissipation control for radiating the LSI 2 is instructed according to the calculated operation rate.

  Therefore, since the operating rate of the LSI 2 connected to the CPU 1 is calculated by the LSI 2 instead of the CPU 1, it is possible to reduce the processing load on the CPU 1 and perform power saving control or heat dissipation control of the LSI 2.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the first embodiment and the second embodiment described above, the operating rate of the CPU 1 or the operating rate of the LSI 2 connected to the CPU 1 is calculated, and power saving control and heat dissipation control of the CPU 1 or LSI 2 are performed. The processing load of the CPU 1 is reduced by performing the processing by the LSI 2 instead of the CPU 1. On the other hand, in the third embodiment, the operating rate of the CPU 1 is calculated by the LSI 2 and the operating rate of the LSI 2 is calculated by the LSI 2, so that the CPU 1 operates in the same manner as in the first and second embodiments. Reduce processing burden.

  FIG. 3 is a block diagram illustrating an electrical configuration of the image forming apparatus according to the third embodiment. In the following description, the same components as those in the image forming apparatus in the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. Therefore, in the following description, only a configuration different from the first embodiment and the second embodiment will be described.

  The image forming apparatus shown in FIG. 3 includes a CPU 1, an LSI 2, a CPU cooling fan 3, and an LSI cooling fan 4.

  The LSI 2 is a chip set connected to the CPU 1 and includes a CPU / LSI operating rate calculation unit 41, a power saving control unit 22 ″, a system clock generation unit 23, an interrupt control unit 24, and a heat dissipation control unit 25 ″. The

  The CPU / LSI operating rate calculating unit 41 includes a CPU power saving control time counting unit 211, a CPU operating rate calculating unit 212, an LSI power saving control time counting unit 311, an LSI operating rate calculating unit 312, an event generating unit 413, and an operation setting register. 414, a counter 415, and a frequency divider 416.

  The event generation unit 413 has the function of the event generation unit 213 in the first embodiment and the function of the event generation unit 313 in the second embodiment. The operation setting register 414 has the function of the operation setting register 214 in the first embodiment and the function of the operation setting register 314 in the second embodiment. The counter 415 has the function of the counter 215 in the first embodiment and the function of the counter 315 in the second embodiment. The frequency divider 416 has the function of the frequency divider 216 in the first embodiment and the function of the frequency divider 316 in the second embodiment.

  The power saving control unit 22 ″ has the function of the power saving control unit 22 in the first embodiment and the function of the power saving control unit 22 ′ in the second embodiment. The heat dissipation control unit 25 ″ has the first function. It has the function of the heat dissipation control unit 25 in the embodiment and the function of the heat dissipation control unit 25 ′ in the second embodiment.

  Note that the power saving / heat radiation control processing of the image forming apparatus in the third embodiment is the same as the power saving / heat radiation control processing of the image forming apparatus in the first embodiment and the second embodiment, and thus description thereof is omitted. To do.

  As described above, the operation time during which the LSI 2 connected to the CPU 1 is operated in a normal state where the power saving control is not performed is measured, and the power saving control time during which the LSI 2 is controlled to save power is measured and measured. The ratio of the operating time to the total time of the operating time and the measured power saving control time is calculated as the operating rate of the LSI 2. Then, at least one of the power saving control of the LSI 2 and the heat dissipation control for radiating the LSI 2 is instructed according to the calculated operation rate.

  Therefore, since the operating rate of the LSI 2 connected to the CPU 1 is calculated by the LSI 2 instead of the CPU 1, the processing load on the CPU 1 can be reduced, power saving control or heat dissipation control of the CPU 1 can be performed, and the LSI 2 can be saved. Power control or heat dissipation control can be performed.

1 is a block diagram illustrating an electrical configuration of an image forming apparatus according to a first embodiment. FIG. 10 is a block diagram illustrating an electrical configuration of an image forming apparatus according to a second embodiment. FIG. 10 is a block diagram illustrating an electrical configuration of an image forming apparatus according to a third embodiment.

Explanation of symbols

1 CPU
2 LSI
3 CPU cooling fan 4 LSI cooling fan 11 Software layer 12 Hardware layer 21 CPU operation rate calculation unit 22, 22 ', 22 "Power saving control unit 23 System clock generation unit 24 Interrupt control unit 25, 25', 25 ”Heat dissipation control unit 31 LSI operation rate calculation unit 41 CPU / LSI operation rate calculation unit 121 Power saving start control unit 122 CPU power saving control unit 123 System clock unit 124 Interrupt determination unit 211 CPU power saving control time count unit 212 CPU operation Rate calculation unit 213, 313, 413 Event generation unit 214, 314, 414 Operation setting register 215, 315, 415 Counter 216, 316, 416 Frequency divider 311 LSI power saving control time count unit 312 LSI operation rate calculation unit

Claims (6)

An electrical device that performs power saving control of the central processing unit,
The integrated circuit connected to the central processing unit is
An apparatus operating time measuring means for measuring an operating time in which the central processing unit is operated in a normal state where power saving control is not performed;
An apparatus power saving control time measuring means for measuring a power saving control time in which the central processing unit is subjected to power saving control;
The ratio of the operating time to the total time of the operating time measured by the apparatus operating time measuring means and the power saving control time measured by the apparatus power saving control time measuring means is the operation of the central processing unit. A device operation rate calculation means for calculating the rate,
Device indicating means for instructing at least one of power saving control of the central processing unit and heat dissipation control for radiating heat from the central processing unit according to the operating rate calculated by the device operating rate calculating unit. Electrical equipment characterized by   The apparatus further comprises an interrupt generating unit that generates an interrupt to the central processing unit when the operating rate calculated by the device operating rate calculating unit reaches a preset interrupt reference value. 1. The electric device according to 1.   The device instructing unit instructs heat dissipation control for radiating heat from the central processing unit when the operation rate calculated by the device operation rate calculating unit reaches a preset heat dissipation reference value. The electrical device according to claim 1. A power saving control unit that receives a power saving control request from the central processing unit and outputs a power saving control permission signal to the device power saving control time measuring unit and the central processing unit;
The apparatus power saving control time measuring means starts measuring the power saving control time during which the central processing unit is subjected to power saving control when a power saving control permission signal is input from the power saving control means,
The central processing unit executes power saving control when a power saving control permission signal is input from the power saving control means,
The apparatus operating rate calculating means divides the operating time by the total time of the power saving control time measured by the apparatus power saving control time measuring means and the operating time measured by the apparatus operating time measuring means. Calculate the operating rate of the central processing unit,
When the operating rate calculated by the device operating rate calculating unit exceeds a preset threshold, the apparatus instruction unit performs power saving control of the central processing unit and heat dissipation control for radiating heat from the central processing unit. 2. The electric device according to claim 1, wherein at least one of them is indicated. Circuit operating time measuring means for measuring an operating time in which the integrated circuit connected to the central processing unit is operated in a normal state where power saving control is not performed;
A circuit power saving control time measuring means for measuring a power saving control time in which the integrated circuit is subjected to power saving control;
The ratio of the operating time to the total time of the operating time measured by the circuit operating time measuring unit and the power saving control time measured by the circuit power saving control time measuring unit is defined as the operating rate of the integrated circuit. Circuit operating rate calculating means for calculating;
Circuit instruction means for instructing at least one of power saving control of the integrated circuit and heat dissipation control for radiating heat from the integrated circuit in accordance with the operating rate calculated by the circuit operating rate calculating means; The electric device according to claim 1. An electrical device that performs power saving control of an integrated circuit connected to a central processing unit,
The integrated circuit comprises:
Circuit operating time measuring means for measuring an operating time in which the integrated circuit is operated in a normal state where power saving control is not performed;
A circuit power saving control time measuring means for measuring a power saving control time in which the integrated circuit is subjected to power saving control;
The ratio of the operating time to the total time of the operating time measured by the circuit operating time measuring unit and the power saving control time measured by the circuit power saving control time measuring unit is defined as the operating rate of the integrated circuit. Circuit operating rate calculating means for calculating;
Circuit instruction means for instructing at least one of power saving control of the integrated circuit and heat dissipation control for radiating heat from the integrated circuit in accordance with the operating rate calculated by the circuit operating rate calculating means. Electrical equipment.

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