JP2006058482A - Imaging apparatus and its operation control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of preventing the shortening of the life of a power source and also concurrently performing stroboscope charging operation and operation for other load, and its operation control method. <P>SOLUTION: The kind of the power source is detected before starting charging a stroboscope (step S51), and the value of an allowable consumed current is set. In a step S53, the temperature of a battery and the number of charging and discharging times are detected, and the value of the allowable consumed current set in the step S51 is calculated according to the temperature of the battery and the number of charging and discharging times, and a current obtained by subtracting the load current of driving load from the allowable consumed current is set as a charge current capable of charging the stroboscope (step S54). When the driving load is generated in the midst of charging a stroboscope capacitor (step S56), a system MPU calculates the load current from the driving load and power source voltage again and calculates the allowable consumed current again (step S57). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus having a built-in or connected strobe and an operation control method thereof.

  In an imaging device with a built-in or connected strobe, a large amount of power is consumed to charge the strobe. For a power source such as a battery that supplies power, the maximum power that can be output is determined in advance. If the maximum power is exceeded, not only the operation is not guaranteed, but also the device itself may be adversely affected. For this reason, various techniques for controlling the supply of power to the strobe have been proposed.

  For example, in the technique of Patent Document 1, power supply to the lens driving system is prohibited during strobe charging. Further, in the technique of Patent Document 2, switching control is performed between a mode in which power is supplied to both the strobe and another operating device and a mode in which power is supplied only to the strobe. However, in such exclusive control, the operation is limited during strobe charging, and the operation intended by the user cannot be performed.

  Further, in the technique of Patent Document 3, the charging time from the light emission of the constituent elements such as the transformer and the capacitor to the completion of charging is stored, and the charging time is kept constant by adjusting the on / off of the charging switching. Adding a limit even though it can be charged quickly is a problem in response.

  In the technique of Patent Document 4, the power saving mode is introduced to reduce the current charged in the strobe capacitor during mode operation, thereby preventing the power supply voltage from dropping and the system from shutting down. However, if the power save mode is set, a decrease in response cannot be avoided.

  In the technique of Patent Document 5, the charging current of the strobe capacitor is switched between two steps, high and low, so that the charging process of the strobe when the power switch is turned on is as fast as possible without imposing a burden on the built-in battery. Like to do. In the technique of Patent Document 6, fast charging, slow charging, and strobe prohibition are switched according to the battery voltage threshold. However, since these techniques have only two values, the response is significantly deteriorated on the low speed side. Resulting in.

  Further, in the technique of Patent Document 7, the strobe charging operation is intermittently started and stopped according to the battery operating voltage, thereby preventing the supply voltage to the control circuit from being lowered when the battery capacity is reduced. In the technique of Patent Document 8, on / off control of the strobe charge booster circuit is performed according to the power supply voltage, so that the strobe charge operation can be continued even during operation of other loads. However, in the techniques of Patent Document 7 and Patent Document 8, only on / off control of strobe charging is performed with respect to other load operations during strobe capacitor charging. May occur, resulting in deterioration of the life of the battery charge cycle.

JP-A-6-205277 Japanese Patent No. 2525642 JP 2004-12556 A JP 2003-46855 A JP 2003-167289 A JP 2000-47302 A JP-A-5-53181 JP 2001-147470 A

  The present invention has been proposed in view of such a conventional situation, and an imaging apparatus capable of preventing a deterioration in the life of a power source and simultaneously performing a strobe charging operation and an operation of another load, and an operation control method thereof. The purpose is to provide.

  Therefore, in order to achieve the above-described object, an imaging apparatus according to the present invention includes a power source that supplies power and a power source type detection unit that detects the type of the power source in an imaging device with a built-in strobe or a connectable device. Voltage detection means for detecting the voltage of the power supply, current consumption detection means for estimating the power supply voltage and current consumption due to the driving load of the imaging device, and the allowable current consumption value according to the type of the power supply. Strobe charge control means for charging the strobe with the value obtained by subtracting the current consumption as the maximum current value that can be charged with the strobe is provided.

  In addition, an operation control method for an image pickup apparatus according to the present invention includes a power supply type detection step for detecting a type of a power supply for supplying power in the operation control method for an image pickup apparatus with a built-in strobe or a connectable device, A voltage detection step for detecting a voltage, a consumption current detection step for estimating the current consumption due to the voltage of the power supply and the driving load of the imaging device, and the consumption current value is subtracted from an allowable consumption current value corresponding to the type of the power supply. And a strobe charge control step of charging the strobe with the value as a maximum current value that can be charged with the strobe.

  According to the present invention, the power supply voltage and the current consumption due to the driving load of the imaging device are estimated, and the value obtained by subtracting the current consumption from the allowable current consumption value according to the type of power supply is set as the maximum current value that can be used for strobe charging. By charging the strobe, a stable current can be supplied from the power source, so that the life of the charging cycle of the power source can be extended. Further, by supplying an optimal charging current based on a load other than the strobe, the charging speed can be improved and the photographing interval can be shortened.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. The image pickup apparatus and its operation control method shown as specific examples control the strobe charging current so as to be obtained by subtracting the load current consumed outside the strobe charging from the allowable power consumption of the power source.

  FIG. 1 is a block diagram showing a configuration of an imaging apparatus 1 according to the present invention. The imaging device 1 includes a lens 2, a lens driving unit 3 that drives the lens 2, a CCD (Charge Coupled Device) 4 that forms an image of a subject via the lens 2, a CCD driving unit 5 that drives the CCD 4, and a CCD 4. A / D converter 6 that converts a video signal representing a subject from the digital signal into digital image data, an image processing unit 7 that performs signal processing such as color balance adjustment, a memory 8 that temporarily stores digital image data, and an LCD An LCD (Liquid Crystal Display) 10 that displays image data that has undergone signal processing through the drive unit 9, a recording device 12 that records digital image data compressed by a system MPU (Micro Processor Unit) 11, a control program, and the like A RAM (Random Access Memory) 13, a strobe 14, a power supply 15 for supplying power to each component block, and types and types of the power supply 15 And a power management unit 16 for detecting voltage.

  The system MPU 11 calculates the load current consumed except for the strobe charging, and sets the strobe charging current value by subtracting the calculated load current from the allowable consumption current of the power supply 15.

  The recording device 12 is a nonvolatile memory (EEPROM: Electrically Erasable Programmable Read Only Memory) such as a Memory Stick (trademark), and stores digital image data.

  The RAM 13 stores a strobe charging current control program executed by the system MPU 11 and an allowable current consumption value corresponding to the power supply 15.

  As will be described later, the strobe 14 includes a transformer that converts a direct current of a certain voltage into a direct current of a different voltage, and a strobe capacitor that is charged by the current converted by the transformer. The strobe 14 may be a built-in strobe or a removable external strobe.

  The power supply 15 includes a battery such as an AC-DC converter or a dedicated rechargeable battery that converts an alternating current of a certain voltage into a direct current of a different voltage, and supplies power to each component block that requires power. 2 and 3 are external views showing the battery connection terminal portion 21 and the battery 31 of the imaging device 1. The battery connection terminal unit 21 includes a battery detection switch 22 that detects a battery, a power source / GND contact 23 that extracts power, and a communication contact 24. In addition, the battery 31 includes a notch 32 for detecting the battery, a power / GND contact 33 for supplying power, and a communication contact 34. The power supply 15 includes storage means for storing power supply information including the type of power supply, and can communicate with the imaging apparatus 1 via the communication contacts 24 and 34.

  The power management unit 16 detects the type of the power supply 15. For example, the type of the battery 31 is detected using the electrical contact of the battery detection switch 22 and the notch 32 of the battery 31 shown in FIGS. Further, the type of the battery 31 may be detected using the communication contacts 24 and 34. Further, the power management unit 16 detects the temperature of the battery 31 using a temperature sensor, and further detects the number of times of charging / discharging using the communication contacts 24 and 34. A strobe charging current, which will be described later, is calculated using the temperature of the battery 31 and the number of times of charging / discharging. In addition, the power management unit 16 detects the voltage of the power supply 15 as necessary.

  Here, power supply to the strobe 14 will be described using a partial configuration 40 of the imaging apparatus 1 shown in FIG. FIG. 4 shows a system MPU 11 corresponding to FIG. 1, a power supply 15, a power management unit 16, a partial configuration 40 of the strobe 14, and other loads 50 other than the strobe 14 requiring the power supply 15. Yes. In the configuration shown in FIG. 4, parts that are the same as those described with reference to FIG. Other loads 50 include the lens driving unit 3, the CCD 4, the CCD driving unit 5, the A / D converter 6, the image processing unit 7, the memory 8, the LCD driving unit 9, and the LCD 10 that require the power supply 15 shown in FIG. Corresponds to the recording device 12 and the RAM 13.

  The strobe charge control unit 41 controls the strobe charge current using the power supplied from the power supply 15. Specifically, the current on the primary winding 42a side of the transformer 42 is detected, and control is performed so that the strobe charging current is the allowable consumption current of the power supply 15 minus the load current consumed outside the strobe charging. As such a technique, JP-A-2003-79417 can be referred to. For example, the current can be changed by obtaining a correlation between the current on the primary winding 42a side, another drive voltage, and the comparison value, and making the comparison value variable in accordance with the limitation of the strobe charging current described later. it can. Thereby, strobe charging can be performed with an optimum current with respect to the voltage drop of the power supply 15.

  The transformer 42 is arranged such that the primary winding 42a and the secondary winding 42b have opposite polarities. As the current level on the primary winding 42a increases, the energy stored in the transformer 42 also increases. The stored energy is taken out from the secondary winding 42 b and charged to the strobe capacitor 43.

  The strobe capacitor 43 maintains a predetermined output voltage level with minimum power consumption by the current of the secondary winding 42b.

  The system MPU 11 outputs a value obtained by subtracting other loads such as lens driving from the allowable current consumption of the power supply 15 to the flash control unit 41 as a flash charging current. This allowable current consumption value is stored in the RAM 13 in advance. Further, the value of the allowable consumption current may be supplied by the microcomputer of the battery 31.

  Next, operation control of the imaging apparatus 1 will be described with reference to a flowchart shown in FIG. Here, a case where a battery 31 that is a dedicated rechargeable battery of the imaging apparatus 1 is used as the power supply 15 will be described.

  First, the type of the power supply 15 is detected using the power supply management unit 16 before the start of strobe charging (step S51). For example, as shown in FIGS. 2 and 3, the type of the power supply 15 is detected when the battery detection switch 22 and the communication contact 24 of the battery connection terminal portion 21 are connected to the notch 32 and the communication contact 34 of the battery 31. Is done. Then, the allowable current consumption value corresponding to the battery 31 detected in step S51 is acquired from the RAM 13, and the value is set. Further, the allowable consumption current value may be acquired from the storage unit of the battery 31.

  Further, the power management unit 16 detects the voltage of the battery 31 (step S52). It is desirable to detect this voltage every time the flash is charged. In addition, when data such as the remaining battery level can be acquired by the communication contacts 24 and 34, the voltage may be detected using the latest data.

  In step S53, the temperature of the battery 31 and the number of charge / discharge cycles are detected. For example, the cell temperature of the battery 31 can be measured using a temperature sensor, and the number of times of charging / discharging can be detected using a microcomputer for identifying the ID of the battery 31. Since the current of the battery 31 is limited by the temperature and the number of times of charging / discharging as shown in FIGS. 6 and 7, the allowable current consumption value set in step S51 is limited according to the temperature of the battery 31 and the number of times of charging / discharging. To do. For example, when the cell temperature of the battery 31 is 40 ° C. and the number of times of charge / discharge is 500 times, the allowable current consumption value is 80% of the allowable current consumption value set in step S51. The allowable current consumption may be limited by using one or both of the temperature and the number of charge / discharge cycles shown in FIGS.

  In step S54, a value obtained by subtracting the load current of the driving load from the allowable consumption current is set as a charging current capable of strobe charging. Since the charging current varies depending on the driving load and the voltage of the battery 31, the charging current is calculated by subtracting the load current corresponding to the driving load. As the voltage of the battery 31, the voltage detected in step S52 can be used. Further, the driving load can be calculated according to the driving conditions of the lens driving unit 3 and the CCD driving unit 5 controlled by the system MPU 11. Here, a current with higher accuracy can be calculated by using a table in which the efficiency with respect to voltage and current is actually measured. As a result, the current output from the power supply 15 can be maintained at a substantially constant value without causing an overcurrent.

  When the calculation of the charging current of the strobe 14 in step S54 is completed, charging is started (step S55). That is, the strobe charge control unit 41 outputs a charging current from the power supply 15 to the primary winding 42 a of the transformer 42. The strobe capacitor 43 is charged by the current of the secondary winding 42b of the transformer 42.

  Here, when a driving load occurs during the charging of the strobe capacitor 43 (step S56), the system MPU 11 recalculates the load current from the driving load and the power supply voltage, and uses the allowable consumption with reference to FIGS. Calculate the current again. Then, the strobe capacitor 43 is charged with a charging current value obtained by subtracting the load current from the allowable consumption current (step S57). If there is no other driving load in step S56, the process proceeds to step S58.

  When the charging of the strobe capacitor 43 is completed (step S58), the light emission preparation of the strobe 14 is completed (step S59). In step S58, when charging of the capacitor 43 is not completed, the process returns to step S56.

  If the power supply 15 is an AC-DC converter, in step S51, the AC-DC converter is specified by the shape of contact or communication, and the allowable current consumption value is set. In step S52, since the voltage hardly fluctuates in the case of the AC-DC converter, the voltage may be detected only at the start-up without being performed every time the flash is charged.

  If the power supply 15 cannot be specified in step S51, it is preferable not to drive the power supply 15 as a system error or to set a value with the smallest allowable load current among the assumed power supplies 15.

  In this way, the strobe current control, which has been conventionally performed only by voltage detection, is controlled by calculating the charging current at the load driving timing other than the strobe 14, thereby preventing overcurrent and extending the life of a battery such as a battery. Can be achieved. In addition, since the charging can be performed with an optimized charging current for driving other loads, the charging speed can be increased to the limit within the limitations that are impossible with the conventional exclusive control. Therefore, as a result, it is possible to produce effects such as shortening the shooting interval and improving the response.

It is a block diagram which shows the imaging device in this Embodiment. It is an external appearance perspective view which shows a battery connection terminal part. It is an external appearance perspective view which shows a battery. It is a block diagram explaining the charge control in this Embodiment. It is a flowchart explaining the operation control in this Embodiment. It is a figure which shows the electric current limitation by temperature. It is a figure which shows the electric current limitation by the frequency | count of charging / discharging.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Imaging device, 2 Lens, 3 Lens drive part, 4 CCD, 5 CCD drive part, 6 A / D converter, 7 Image processing part, 8 Memory, 9 LCD drive part, 10 LCD, 11 System MPU, 12 Recording apparatus, 13 RAM, 14 Strobe, 15 Power, 16 Power management unit, 21 Battery connection terminal, 22 Battery detection switch, 23 Power supply / GND contact, 24 Communication contact, 31 Battery, 32 Notch, 33 Power supply / GND contact, 34 Communication Contact, 40 Strobe configuration 41 Strobe charge controller, 42 Transformer, 43 Strobe capacitor

Claims (12)

In an imaging device with a built-in strobe or connectable,
A power supply for supplying power;
Power source type detection means for detecting the type of the power source;
Voltage detecting means for detecting the voltage of the power source;
Current consumption detecting means for estimating the current consumption due to the voltage of the power source and the driving load of the imaging device;
A strobe charge control means for charging the strobe with a value obtained by subtracting the consumption current from an allowable consumption current value corresponding to the type of the power supply as a maximum current value that can be used for strobe charging. Comprising storage means for storing an allowable current consumption value according to the type of power supply;
The strobe charge control means extracts an allowable current consumption value corresponding to the power supply type detected by the power supply type detection means from the storage means, and obtains a value obtained by subtracting the current consumption from the extracted allowable current consumption value. The imaging apparatus according to claim 1, wherein the strobe is charged as a maximum current value that can be charged.   2. The image pickup apparatus according to claim 1, wherein the power supply type detection means detects the type of power supply based on a physical shape or a shape of an electrical contact at a connection portion between the power adapter or the battery and the image pickup apparatus.   The power adapter or battery includes storage means for storing power information including the type of power supply, and the power supply type detection means has communication means for communicating with the power adapter or battery storage means. The imaging apparatus according to claim 3, wherein information is received.   The imaging apparatus according to claim 1, wherein the current consumption detecting unit estimates a current consumption based on a table representing an allowable current consumption efficiency of the power source.   6. The imaging apparatus according to claim 5, wherein the table includes a change in the allowable current consumption value depending on the number of times of charging / discharging and / or a change in the allowable current consumption value depending on a battery cell temperature. In an operation control method of an imaging device with a built-in strobe or connectable,
A power source type detection step for detecting the type of power source for supplying power;
A voltage detection step of detecting the voltage of the power source;
A current consumption detecting step for estimating the current consumed by the power supply voltage and the driving load of the imaging device;
A strobe charge control step of charging the strobe with a value obtained by subtracting the current consumption from an allowable current consumption value according to the type of power supply as a maximum current value that can be used for strobe charging. Control method. A storage step of storing an allowable current consumption value according to the type of power supply in the storage means;
In the strobe charge control step, an allowable current consumption value corresponding to the type of power source detected in the power source type detection step is extracted from the storage means, and a value obtained by subtracting the current consumption from the extracted allowable current consumption value is obtained as a strobe. 8. The operation control method for an imaging apparatus according to claim 7, wherein the strobe is charged as a maximum current value that can be charged.   8. The operation of the image pickup apparatus according to claim 7, wherein, in the power supply type detection step, the type of the power supply is detected by a physical shape or a shape of an electrical contact at a connection portion between the power adapter or the battery and the image pickup apparatus. Control method.   The power adapter or battery includes storage means in which power information including the type of power is stored, and the power type detection step communicates with the power adapter or battery storage means and receives the power information. An operation control method for an imaging apparatus according to claim 9.   8. The operation control method for an imaging apparatus according to claim 7, wherein, in the consumption current detection step, the consumption current is estimated based on a table representing an allowable consumption current efficiency of the power source.   12. The operation control method for an imaging apparatus according to claim 11, wherein the table includes a change in the allowable current consumption value depending on the number of times of charging and discharging and / or a change in the allowable current consumption value depending on a battery cell temperature.

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