JP2015210546A - Electronic apparatus and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption while maintaining processing performance.SOLUTION: A signal processing unit (104) can operates at different voltages. In a memory (105), a characteristic value to which an individual difference of the signal processing unit (104) is reflected is stored. A power supply type detection unit (103) detects the type of a power supply (101). A voltage control unit (102) determines a setting voltage of the signal processing unit (104) according to the characteristic value which is read from the memory (105), and controls the voltage of the signal processing unit (104) to the setting voltage in a sequence based on the power supply type which is detected by the power supply type detection unit (103).

Description

  The present invention relates to an electronic device that can use a plurality of types of power supplies.

  In order to improve the performance of an electronic device, it is necessary to increase the processing speed of the electronic device by increasing the frequency of the operation clock of the entire processing system of the electronic device. However, if the operation clock frequency is increased, the power consumption increases, so that the operable time in the case of battery operation decreases.

  As a method for reducing the power consumption of an electronic device, a technique for controlling a voltage supplied to a necessary part of the electronic device according to the function of the electronic device is known (Patent Document 1).

JP 2009-302710 A

  Many modern electronic devices can use multiple types of power supplies. For example, electronic devices that can be used by selecting any one of a battery, an external AC power supply, and an external DC power supply (for example, USB power supply) are widely used. When using an external AC power source, there are a case where a so-called AC adapter is used and a case where a non-contact power supply system is used.

  The technology described in Patent Document 1 is based on the premise of stable power supply to electronic devices, and no consideration has been given to the case where a power supply that cannot be expected to provide stable power supply is selected.

  Therefore, an object of the present invention is to reduce power consumption in accordance with the type of power supply connected to an electronic device.

  An electronic device according to the present invention is an electronic device that can use a plurality of different types of power supplies, and a signal processing unit that can operate at different voltages, and a power supply type detection that detects the type of power supply that supplies power to the electronic device. Means, a memory for storing a characteristic value reflecting individual differences of the signal processing unit, a set voltage of the signal processing unit is determined according to the characteristic value, and the voltage of the signal processing unit is determined according to the type of the power source And control means for controlling the set voltage in a sequence.

  ADVANTAGE OF THE INVENTION According to this invention, power consumption can be reduced according to the kind of power supply connected to an electronic device.

It is a schematic block diagram of one Example of this invention. It is a flowchart which shows an example of the power supply control process of a present Example. It is a flowchart which shows an example of the margin determination process of a present Example. It is a flowchart which shows an example of the voltage control process of a present Example. It is an example of the sequence of the voltage control of a present Example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram of a schematic configuration of an imaging apparatus which is an example of an electronic apparatus according to the invention. The imaging apparatus 100 includes, as a power supply 101, any one of a battery 200 that can be attached to and detached from the imaging apparatus 100, an external apparatus 300 that outputs DC power, an AC adapter 400 that generates DC power from commercial AC power, and a wireless power feeding apparatus 500. It is selectively available. The external device 300 is a device having an output interface that supports the supply of DC power, such as a USB (Universal Serial Bus). The wireless power supply apparatus 500 is a power supply apparatus that uses a transmission system that supplies power in a non-contact manner such as coil coupling or electrostatic coupling.

  The voltage control unit 102 generates a voltage (power supply voltage and reference voltage) to be supplied to each unit of the imaging apparatus 100 from power from a device selected as the power source 101 and controls voltage supply to each unit of the imaging apparatus 100.

  The power supply type detection unit 103 detects whether the battery 200, the external device 300, the AC adapter 400, or the wireless power supply device 500 is selected as the power supply 101.

  The signal processing unit 104 processes an image signal output at the time of shooting from an imaging element such as a CCD sensor or a CMOS sensor (not shown), and processes a signal for controlling each block in the imaging device 100.

  The memory 105 stores characteristic values for the power supply voltage of the signal processing unit 104. The characteristic value stored in the memory 105 is, for example, a value obtained by converting the performance of the transistor used in the signal processing unit 104 into the ring oscillator rotational speed. The characteristic value stored in the memory 105 changes depending on individual variations of the signal processing unit 104. The rotation speed of the ring oscillator represents the delay characteristic of the transistor. If this value is small, the delay time of the circuit increases and current does not flow easily. In addition, if the ring oscillator rotational speed is large, the delay time is shortened and current flows easily. The number of rotations of the ring oscillator of the transistor used in the signal processing unit 104 varies depending on manufacturing variations and applied voltage. The voltage control unit 102 refers to the characteristic value stored in the memory 105 when controlling the power supply voltage supplied to the signal processing unit 104.

  The voltage level measurement sensor 106 measures an appropriate power supply voltage supplied to the signal processing unit 104.

  The time measuring unit 107 is used to determine the voltage change timing when the voltage is changed stepwise.

  The storage unit 108 stores a voltage control eigenvalue used when performing voltage control.

  Each of the blocks 102 to 108 is connected to a bus 109 and exchanges various data via the bus 109. The voltage control unit 102 supplies a power supply voltage to the blocks 103 to 108 via individual power supply lines (not shown). The voltage control unit 102 may supply the power supply voltage via a common power supply line to blocks that may have the same power supply voltage.

  With reference to the flowchart shown in FIG. 2, the voltage control process in a present Example is demonstrated.

  When the imaging apparatus 100 is activated, the power supply type detection unit 103 detects the type of the power supply 101 that supplies power to the imaging apparatus 100 (S200). For example, the power supply type detection unit 103 detects which of the battery 200, the external device 300, and the AC adapter 400 the power supply 101 corresponds to based on the voltage value, supply current, ripple, and the like.

  The voltage control unit 102 reads the characteristic value of the signal processing unit 104 from the memory 105 (S201). As described above, this characteristic value is a value indicating the performance of a circuit element such as a transistor used in the signal processing unit 104, for example, the number of rotations of the ring oscillator, and is an index indicating the ease of current flow. Since the voltage required by the signal processing unit 104 changes according to the performance of the circuit element, this characteristic value is used when determining an appropriate voltage value of the power supply voltage applied to the signal processing unit 104. By determining the power supply voltage value using this characteristic value, variations during manufacturing of the signal processing unit 104 can be absorbed, and an appropriate power supply voltage can be applied to the signal processing unit 104 for each individual.

  The voltage control unit 102 adds a margin considering the aging of the internal circuit of the signal processing unit 104 and the power supply type obtained from the power supply type detection unit 103 to the characteristic value read in S201 (S202). The margin determination method in S202 will be described later. Since the characteristic value indicates the rotation speed of the ring oscillator, the margin is also a value converted to the rotation speed of the ring oscillator. In the following description, unless otherwise specified, the margin is treated as a converted value of the ring oscillator rotation speed.

  The voltage control unit 102 drives the voltage level measurement sensor 106 with the characteristic value with a margin added in S202, and calculates an error between the voltage currently applied to the signal processing unit 104 and the appropriate voltage to the voltage level measurement sensor 106. (S203). When the voltage control unit 102 transmits the number of rotations of the ring oscillator considering the transistor performance and margin to the voltage level measurement sensor 106, the voltage level measurement sensor 106 compares the number of rotations with the voltage applied at that time. The error is calculated. The voltage level measurement sensor 106 notifies the calculated error to the signal processing unit 104 via the bus 109.

The signal processing unit 104 obtains an appropriate voltage based on the error notified from the voltage level measurement sensor 106, and notifies the voltage control unit 102 of the obtained appropriate voltage value (S204). The error is calculated as a percentage (-100% to 100%). Assuming that the power supply voltage of the signal processing unit 104 at that time is Vc and the error is e, the appropriate voltage value Va is calculated using the following equation:
Va = Vc (1 + e / 100)
And can be calculated. The signal processing unit 104 notifies the calculated appropriate voltage value Va to the voltage control unit 102 via the bus 109.

  The voltage control unit 102 uses the appropriate voltage value Va notified from the signal processing unit 104 as a set voltage (or target voltage), and performs control in a predetermined sequence so that the voltage supplied to the signal processing unit 104 becomes the set voltage ( S205). Details of the power control by the voltage control unit 102 in S205 will be described later.

  With reference to FIG. 3, the margin determination method in step S202 will be described. The margin is used for safety measures to prevent the voltage value necessary for the operation of the imaging apparatus 100 from being lower than the minimum, and for improving the processing performance of the imaging apparatus 100. Specifically, when the voltage level measurement sensor 106 is driven using only the characteristic values stored in the memory 105, the appropriate voltage of the signal processing unit 104 at that time is obtained. Therefore, when the voltage level measurement sensor 106 is driven with a value obtained by adding a margin to the characteristic value stored in the memory 105, a voltage value larger than the appropriate voltage is obtained. That is, the voltage value supplied to the signal processing unit 104 is a value obtained by adding the voltage value calculated from the margin to the voltage value calculated from the characteristic value stored in the memory 105. As a result, the signal processing unit 104 can easily cope with processing that requires more power without waiting for the power supply voltage to rise.

  In this embodiment, the margin is determined according to the power supply type by changing the margin determination method according to the power supply type.

  When the power source 101 is not the external device 300 and the AC adapter 400 but the battery 200 (Yes in S300), the voltage control unit 102 determines a margin by a margin determination process corresponding to the battery 200 (S301). In the case of the battery 200, stable power supply cannot always be expected, and the power supply capability varies depending on the type of battery, such as a primary battery such as an alkaline manganese dry battery or a secondary battery such as a lithium ion battery. Therefore, the voltage control unit 102 drives the voltage level measurement sensor 106 every time a predetermined time elapses, and periodically changes the voltage supplied to the signal processing unit 104. In this case, the margin to be added is made smaller than when the power source 101 is the external device 300 or the AC adapter 400 in consideration of only factors due to aging in order to reduce power consumption. Accordingly, the minimum voltage value required by the signal processing unit 104 at that time can be obtained in consideration of aging deterioration, and the power consumption of the imaging apparatus 100 can be suppressed.

  When the power source 101 is a dry battery in which a sudden drop in output voltage is likely to occur compared to a lithium ion battery or the like, for example, an alkaline manganese dry battery, the processing that consumes a large amount of power in the imaging device 100 is limited, and other batteries (for example, The margin is smaller than that of a lithium ion battery. Thereby, power consumption can be reduced.

  The voltage level measurement sensor 106 may be driven to perform voltage change control when the processing of the imaging apparatus 100 is switched or when the remaining battery level falls below a predetermined threshold. The battery remaining amount threshold value may be provided at a plurality of levels, and the voltage change control may be executed each time the threshold value is lowered.

  Still another method may be as follows. In other words, when the remaining battery level falls below a predetermined threshold, processing with large power consumption of the imaging apparatus 100 is limited. Then, the voltage level measurement sensor 106 is driven in accordance with the process with the highest power consumption among the unrestricted processes, and the set voltage is lowered based on the result.

  When the power supply 101 is the AC adapter 400 (Yes in S302), the voltage control unit 102 determines a margin by a margin determination process corresponding to the AC adapter 400 (S303). When the imaging apparatus 100 is driven by the output of the AC adapter 400, the rated voltage of the imaging apparatus 100 is supplied to the voltage control unit 102. Based on this rated voltage, the voltage control unit 102 performs voltage control on each block.

  In this case, since stable power supply is expected, the voltage control unit 102 determines the voltage of the signal processing unit 104 by driving the voltage level measurement sensor 106 only when the imaging apparatus 100 is activated. Prioritizing the performance of the imaging device 100, the margin for driving the voltage level measurement sensor 106 is made larger than when the battery 200 is used as the power source 101. For example, the margin is determined in consideration of the aging degradation consideration and the processing with the largest power consumption of the imaging apparatus 100.

  In some cases, the battery 200 and the AC adapter 400 can be used simultaneously as the power source 101. In such a case, not only when the imaging apparatus 100 is started, but also when the power source 101 is the battery 200 instead of the AC adapter 400, the signal processing unit is periodically or every time the processing of the imaging apparatus 100 is switched. The voltage change control 104 may be executed. That is, the voltage control unit 102 drives the voltage level measurement sensor 106 at such timing, reduces the supply voltage to the signal processing unit 104 according to the margin, and uses the reduced amount for charging the battery 200. However, when the voltage is lowered, the signal processing unit gives priority to the processing of the imaging device 100 and sets the voltage setting value higher by a predetermined ratio than the voltage value obtained from the driving result of the voltage level measurement sensor 106, for example. The supply voltage to 104 is given a margin.

  When the power supply 101 is the external device 300 (Yes in S304), the voltage control unit 102 determines a margin by a margin determination process corresponding to the external device 300 (S305). When power is supplied from the external device 300, stable power supply can be expected as in the case of the AC adapter 400. Therefore, the voltage control unit 102 drives the voltage level measurement sensor 106 only when the imaging device 100 is activated, thereby increasing the margin. decide. However, since the power supply capability varies depending on the type or type of the external device 300, the voltage control unit 102 changes the margin according to the power supply capability of the external device 300. Specifically, in the case of USB connection, a parameter indicating the power supply capability of the external device 300 can be acquired. Therefore, the voltage control unit 102 determines the power supply capability based on this parameter and determines a margin. When the power supply capability of the external device 300 is small, the margin is reduced, and conversely, when it is large, the margin is increased.

  In some cases, the battery 200 and the external device 300 can be used simultaneously as the power source 101. In such a case, not only when the imaging apparatus 100 is started, but also when the power source 101 is the battery 200 instead of the external apparatus 300, the signal processing unit is periodically or every time the processing of the imaging apparatus 100 is switched. The voltage change control 104 may be executed. That is, the voltage control unit 102 drives the voltage level measurement sensor 106 at such timing, reduces the supply voltage to the signal processing unit 104 according to the margin, and uses the reduced amount for charging the battery 200. However, when the voltage is lowered, the signal processing unit gives priority to the processing of the imaging device 100 and sets the voltage setting value higher by a predetermined ratio than the voltage value obtained from the driving result of the voltage level measurement sensor 106, for example. The supply voltage to 104 is given a margin.

  When the power supply type detection unit 103 cannot determine the type of the power supply 101 (No in S304), the voltage control unit 102 determines a margin in the same manner as in the case of the battery 200 with poor conditions (S306). That is, the voltage control unit 102 drives the voltage level measurement sensor 106 at a predetermined timing, such as periodically or every time the processing of the imaging apparatus 100 is switched, with a margin that takes into account only factors due to aging. Since the characteristics of the power supply 101 cannot be grasped, the voltage control unit 102 assumes that the battery 200 has worse conditions than the external device 300 and the AC adapter 400 and does not execute voltage change control by driving the voltage level measurement sensor 106.

  FIG. 4 shows a detailed flowchart of voltage control (S205) by the voltage control unit 102. FIG. 5 shows a transition example of voltage control for each power supply type. In the graphs of FIGS. 5A to 5D, the horizontal axis indicates time, and the vertical axis indicates voltage. t1> t2 and V1 <V2. t1 and t2 are measured by the time measuring unit 107. If the target voltage is not reached by a single voltage change, the voltage is changed to the target voltage by repeating the process of changing the voltage after a predetermined time (corresponding to the step-down interval described below) has elapsed.

  With reference to FIG.4 and FIG.5, the detailed operation | movement of step S205 is demonstrated. In the present embodiment, the voltage control unit 102 changes the voltage control according to the type of the power source 101, that is, the power supply capability of the power source 101 so as not to apply an excessive load to the power source 101.

  The voltage control unit 102 stores the error found in S203 of FIG. 2 (the error between the voltage including the margin and the current applied voltage) in the storage unit 108 as a voltage control eigenvalue. Next, the voltage control unit 102 causes the signal processing unit 104 to calculate a set voltage from the voltage control eigenvalue and the current applied voltage, and changes the voltage applied to the signal processing unit 104 to the set voltage value.

  When the power supply 101 is not the external device 300 and the AC adapter 400 but the battery 200 (Yes in S400), the voltage control unit 102 controls the voltage applied to the signal processing unit 104 by the voltage control process corresponding to the battery 200 ( S401). FIG. 5A shows a sequence example of voltage control processing corresponding to the battery 200. Since a large load cannot be applied to the battery 200 as compared with the external device 300 and the AC adapter 400, the voltage to be stepped down at once (hereinafter referred to as “step-down amount”) is small and the voltage is stepped down once. The time required to step down (hereinafter referred to as “step-down interval”) is lengthened. One or both of the step-down amount, that is, the voltage change amount and the step-down interval, that is, the voltage change interval may be changed depending on the type of the battery 200. For example, in the case of a manganese dry battery that is weaker in load than a lithium ion battery, the step-down amount is made smaller than V1 and / or the step-down interval is made larger than t1.

  Furthermore, the voltage control process may be changed when the remaining amount of the battery 200 falls below a predetermined threshold. For example, when the remaining amount of the battery 200 decreases, there is a high possibility that a stronger load than before will not be applied, so the step-down amount is made smaller than before and / or the step-down interval is made larger than before. A plurality of thresholds for the remaining amount of the battery 200 may be provided, and the above-described step-down amount and / or step-down interval may be changed every time the threshold is lowered.

  When the power supply 101 is the AC adapter 400 (Yes in S402), the voltage control unit 102 controls the voltage applied to the signal processing unit 104 by the voltage control process corresponding to the AC adapter 400 (S403). FIG. 5B shows a sequence example of voltage control processing corresponding to the AC adapter 400. Since a load larger than that of the battery 200 can be applied to the external device 300 and the AC adapter 400, the amount of step-down in the voltage control process is increased and the step-down interval is shortened. As a result, the voltage applied to the signal processing unit 104 can be changed to the set voltage earlier, so that voltage control can be performed with emphasis on the processing performance of the imaging apparatus 100.

  When the power supply 101 is the external device 300 (Yes in S404), the voltage control unit 102 controls the voltage applied to the signal processing unit 104 by the voltage control process corresponding to the external device 300 (S405). There are a case where the power supply capability of the external device 300 used is equivalent to that of the AC adapter 400 and a case where it is lower than that of the AC adapter 400. In the former case, the voltage control unit 102 controls the voltage of the signal processing unit 104 in the sequence shown in FIG. In the latter case, the voltage control unit 102 controls the voltage of the signal processing unit 104 in the sequence shown in FIG. 5C or FIG. In the control sequence shown in FIG. 5C, the step-down interval is made larger than the sequence shown in FIG. In the control sequence shown in FIG. 5D, the step-down amount is made smaller than that in the sequence shown in FIG. A combination of the control shown in FIG. 5C and the control shown in FIG. 5D may increase the step-down interval and reduce the step-down amount.

  When the power supply type detection unit 103 cannot detect the type of the power supply 101 (No in S404), the voltage control unit 102 controls the voltage applied to the signal processing unit 104 in the voltage control process when the power supply type detection is not possible ( S406). Similar to the margin determination method, when the type of the power source 101 cannot be detected, the voltage control unit 102 executes the same voltage control process as that when the battery 200 is used as the power source 101. The step-down interval and the amount of step-down are the same as in the example shown in FIG. However, since the characteristics of the power supply 101 cannot be grasped, the power supply 101 is not changed by the threshold voltage control as the battery 200 does.

  Although the step-down voltage control for decreasing the voltage has been described, the same applies to the step-up for increasing the voltage. That is, when power is stably supplied, the time until the next boosting is shortened and the voltage boosted at a time is increased. If stable power supply cannot be expected, the time until the next boosting is lengthened and the voltage boosted at a time is reduced.

  The present invention is not limited to the above-described embodiments, and various applications are possible without departing from the spirit of the invention. For example, in the above description, the voltage applied to the signal processing unit is controlled, but the present invention can also be applied to voltage control for other blocks constituting the imaging device.

  In calculating the voltage to be applied to the signal processing unit, the characteristic value indicating the performance of the transistor is used. However, the characteristic value of other circuit elements used in the signal processing unit may be used. You may calculate using the performance of multiple types of circuit elements in combination.

  Although the embodiment applied to the imaging apparatus 100 has been described as an example of an electronic apparatus, the present invention is an electronic apparatus that can use a plurality of power sources of different types or types, such as a PDA (Personal Digital Assistance) and a portable terminal. It can also be applied to mobile devices.

  The cable that supports power supply for connecting the external apparatus 300 and the imaging apparatus 100 is not limited to the USB cable, and other connection means that can supply power can also be used. For example, there are MHL (Mobile High-definition Link) compatible cables and PoE (Power over Ethernet (registered trademark)). Note that when the power supply 101 is the wireless power supply apparatus 500, the imaging apparatus 100 performs the same processing and control as when the power supply 101 is the external apparatus 300.

  Further, a software program that realizes part or all of the functions of the above-described embodiments is supplied to a system or apparatus having a computer that can execute the program directly from a recording medium or using wired / wireless communication. The case where the program is executed is also included in the present invention. Since the functions of the present invention are implemented by computer, the program code itself supplied or installed in the computer also implements the present invention. That is, the computer program itself for realizing the functional processing of the present invention is also included in the present invention.

Claims (10)

An electronic device that can use different types of power supplies,
A signal processor that can operate at different voltages;
Power supply type detection means for detecting the type of power supply for supplying power to the electronic device;
A memory for storing characteristic values reflecting individual differences of the signal processing unit;
An electronic apparatus comprising: control means for determining a set voltage of the signal processing unit according to the characteristic value and controlling the voltage of the signal processing unit to the set voltage in a sequence according to the type of the power source. The control means includes
A voltage level measurement sensor that is driven according to the characteristic value and measures the voltage level of the signal processing unit;
2. The electronic apparatus according to claim 1, further comprising means for determining the set voltage according to the voltage level measured by the voltage level measurement sensor. The control means includes
A voltage level measurement sensor that is driven according to the result of adding a margin to the characteristic value and measures the voltage level of the signal processing unit;
2. The electronic apparatus according to claim 1, further comprising means for determining the set voltage according to the voltage level measured by the voltage level measurement sensor. The control means includes
Means for determining a margin according to the type of the power supply detected by the power supply type detection means;
A voltage level measurement sensor that is driven according to a result of adding the margin to the characteristic value and measures a voltage level of the signal processing unit;
2. The electronic apparatus according to claim 1, further comprising means for determining the set voltage according to the voltage level measured by the voltage level measurement sensor.   5. The electronic device according to claim 1, wherein the control unit controls the voltage of the signal processing unit at a predetermined timing including when the electronic device is activated.   The electronic apparatus according to claim 1, wherein the characteristic value indicates a performance of a circuit element used in the signal processing unit.   The electronic device according to claim 1, wherein the control unit controls the voltage applied to the signal processing unit in a stepwise manner toward the set voltage.   The electronic device according to claim 7, wherein the control unit determines at least one of a voltage change amount and a voltage change interval of a voltage applied to the signal processing unit according to a type of the power source.   The electronic device according to any one of claims 1 to 8, wherein the type of power source includes two or more of a battery, an AC adapter, a USB (Universal Serial Bus), and wireless power feeding. A method for controlling an electronic device that includes a signal processing unit that can operate at different voltages and that can use a plurality of different types of power supplies,
A power source type detecting step for detecting a type of power source for supplying power to the electronic device;
Determining a set voltage of the signal processing unit according to a characteristic value reflecting individual differences of the signal processing unit;
And a control step of controlling the voltage of the signal processing unit to the set voltage in a sequence according to the type of the power source.

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