JP4231257B2 - camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a camera that performs a battery check operation that prevents a battery end from being determined in spite of a new battery when an environmentally friendly battery that does not contain mercury has a large internal resistance.
[0002]
[Prior art]
Conventionally, the battery check method for a camera is to connect a battery with an actual load such as a stepping motor or a dummy load such as a resistance element for a short time to extract a relatively large current from the battery and compare the battery voltage at that time with a predetermined voltage. In general, it is determined whether or not the remaining battery level is sufficient.
[0003]
In other words, the discharge characteristics (life characteristics) of alkaline manganese batteries used in cameras are generally such that the voltage gradually decreases and the internal resistance increases as they are used, but the storage period is particularly long. In the case of a new battery, there is a phenomenon that the internal resistance is relatively large at the initial stage of use.
[0004]
In particular, this phenomenon is remarkable in an alkaline manganese battery that does not contain mercury in consideration of the environment, and therefore, the initial internal resistance may be larger than the internal resistance at the actual life stage. If such a battery is subjected to a battery check by the above-described method, it is determined that the battery has ended even though it is a new battery.
[0005]
For such problems, Japanese Patent Application Laid-Open No. 6-281710 (Japanese Patent Application No. 5-90517), Japanese Patent Application Laid-Open No. 7-64146 (Japanese Patent Application No. 5-209553), Japanese Patent Application Laid-Open No. 7-181548 (Japanese Patent Application No. 5). -325426), Japanese Patent Application Laid-Open No. 8-184752 (Japanese Patent Application No. 5-337639), Japanese Patent Application Laid-Open No. 8-211135 (Japanese Patent Application No. 7-18277), and the like.
[0006]
First, in Japanese Patent Laid-Open No. 6-281710, the battery activation means is energized before the battery check operation. In this method, the battery is activated every time the battery check is performed.
[0007]
Also, in Japanese Patent Application Laid-Open No. 7-64146 (Japanese Patent Application No. 5-209553), when conducting a battery check by energizing a dummy load, a period in which the voltage immediately drops immediately after energizing the load (period in which the internal resistance is large) ), And the determination is based on the voltage when the voltage becomes almost flat after a sufficient time. In this case, the time required for the battery check in the camera is required to be within about 100 msec considering the time lag to the shutter.
[0008]
Japanese Patent Application Laid-Open No. 7-181548 (Japanese Patent Application No. 5-325426) performs a plurality of voltage measurements while energizing a load, and at least the voltage immediately after energization and the voltage after time has elapsed. The difference is obtained, and it is determined whether the obtained voltage data is based on the initial characteristics of the battery not containing mercury or the characteristics in the battery life.
[0009]
Further, Japanese Patent Application Laid-Open No. 8-84752 (Japanese Patent Application No. 5-337639) is a camera having an active AF function (ranging function) for measuring a battery voltage during a light projecting operation. It is limited to cameras.
[0010]
In Japanese Patent Application Laid-Open No. 8-211135 (Japanese Patent Application No. 7-18277), the load for checking the battery is energized for a short time (the time when the lamp does not light up), etc. Repeat the comparison of the battery voltage with the reference voltage. At this time, the voltage measured at the time of the first energization is compared with a relatively low reference voltage, and after that, it is compared with a relatively high reference voltage, and the remaining battery level is determined based on the comparison result. .
[0011]
[Problems to be solved by the invention]
However, in Japanese Patent Laid-Open No. 6-281710, even a battery that does not require activation is activated, and there is a problem that not only power is consumed but also the time lag until the shutter operation is large. .
[0012]
In Japanese Patent Application Laid-Open No. 7-64146, a mercury-free alkaline manganese battery is energized to the dummy load. For example, when the energization is continued for about 100 msec, the voltage immediately before the energization is almost flat becomes a voltage. Even if it exists, since the same thing as the voltage when a battery is actually consumed (voltage at the time of a battery life) is experimentally recognized, when it considers the dispersion | variation in a battery, it is not a sufficient measure. On the other hand, setting the energization time to the dummy load to 1 second is not practical because it greatly affects the camera sequence and takes time to operate the camera.
[0013]
The method disclosed in Japanese Patent Application Laid-Open No. 7-181548 requires, for example, an A / D converter, a plurality of comparators, a reference voltage, and the like to collect, calculate, and compare a plurality of voltage data. Therefore, there is a disadvantage that the cost of the camera in the popular price range is greatly increased.
[0014]
The method disclosed in Japanese Patent Laid-Open No. 8-211135 is limited to a camera having an appropriate load such as a lamp, and requires a plurality of reference voltages for comparing voltages. This camera has the disadvantage of significantly increasing the cost.
[0015]
The present invention has been made paying attention to the problems of such a conventional camera, and it is an object of the present invention to provide a camera that is not judged to be a battery end even when a new battery is loaded. And
[0016]
[Means for Solving the Problems]
  In order to solve the above problem, in the camera of the present application,A strobe charging circuit for charging a main capacitor for strobe emission with a battery, a battery check means for comparing the voltage of the battery with a reference voltage, a comparison result of the battery check means while controlling the battery check means and the strobe charging circuit And a control means for determining a battery end of the battery based on the camera, and performs a battery check operation,
The battery check means includes a dummy load, and a switching transistor for passing current to the dummy load by the battery.,
  The battery check operation is
  A dummy load is energized for a predetermined time by the switch transistor, and the battery check means compares the voltage of the battery at this time with the reference voltage,
  When the battery voltage is higher than the reference voltage, it is determined that the remaining battery level is sufficient,
When the battery voltage is less than or equal to the reference voltage, after the predetermined time has elapsed, the strobe charging circuit charges the main capacitor for a certain period of time,
After the fixed time has elapsed, a dummy load is energized by the switch transistor for a predetermined time, and the battery check means compares the battery voltage at this time with the reference voltage.,
  When the voltage of the battery is equal to or lower than the reference voltage, it is determined that the battery is at the end of the battery. When the voltage of the battery is higher than the reference voltage, it is determined that the remaining battery level is sufficient.It is characterized by that.
[0018]
The camera according to claim 2 of the present application is characterized in that in the camera according to claim 1, the battery check means performs the battery check operation when a main switch of the camera is turned on.
[0019]
  In the camera according to claim 3 of the present application, in the camera according to claim 1,When a battery is inserted and a power-on reset is applied to the control meansThe battery check means performs the battery check operation.
[0020]
  In the camera according to claim 4 of the present application, in the camera according to claim 1,When the main switch of the camera is turned on, the control means charges regardless of the charging state of the main capacitor of the strobe charging circuit.It is characterized by performing.
[0021]
  In the camera according to claim 5 of the present application, in the camera according to claim 1,The control means has a low power consumption mode and a shootable mode, and when the shootable mode is activated from the low power consumption mode, the control meansCharging is performed regardless of the charging state of the main capacitor of the strobe charging circuit.
[0022]
  The camera according to claim 6 of the present application is the camera according to claim 1,AboveThe control means has a low power consumption mode and a shootable mode. When the shootable mode is activated from the low power consumption mode, the control means determines how the main capacitor of the strobe charging circuit is charged. Regardless of the feature, it is charged.
[0023]
  In the camera according to claim 7 of the present application, in the camera according to claim 1, a battery is loaded in the camera.AboveWhen the power ON reset is applied to the control means, the control means performs charging regardless of the charge state of the main capacitor of the strobe charging circuit.
[0024]
  In the camera of claim 8 of the present application,A strobe charging circuit for charging a main capacitor for strobe emission with a battery, a battery check means for comparing the voltage of the battery with a reference voltage, a comparison result of the battery check means while controlling the battery check means and the strobe charging circuit Control means for determining the battery end of the battery based on the above, and means for detecting the charged state of the main capacitor, the control means is a camera that performs a battery check operation when the main switch is turned on. ,
  The battery check means includes a dummy load, and a switching transistor for passing current to the dummy load by the battery,
  The battery check operation is
  A dummy load is energized for a predetermined time by the switch transistor, and the battery check means compares the voltage of the battery at this time with the reference voltage,
  When the battery voltage is higher than the reference voltage, it is determined that the remaining battery level is sufficient,
When the voltage of the battery is equal to or lower than the reference voltage, after the elapse of the predetermined time, the strobe charging circuit charges the main capacitor for a time corresponding to the charging state of the main capacitor,
  After the lapse of a certain time, a dummy load is energized for a predetermined time by the switch transistor, and the battery check means compares the voltage of the battery at this time with the reference voltage,
When the voltage of the battery is equal to or lower than the reference voltage, it is determined that the battery is at the end of the battery, and when the voltage of the battery is higher than the reference voltage, it is determined that the remaining amount of the battery is sufficient.Features.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a camera according to an embodiment of the present application will be described with reference to the drawings. FIG. 2 is a block diagram of a camera according to an embodiment of a portion related to the invention of the present application.
[0026]
Reference numeral 1 denotes a control circuit as a part of the control means for controlling the operation of the camera. The control circuit 1 includes a microcomputer, an interface circuit, and other peripheral circuits. A program for controlling almost all operations of the camera, such as winding, parameters such as initial values and reference values for operation, data for operation, and the like are stored.
[0027]
This camera has a battery check circuit 3 that determines whether or not the remaining amount of the battery is sufficient by comparing a voltage VBC related to the voltage VB (battery voltage) of the battery 2 with a predetermined reference voltage Vref. Yes.
[0028]
The battery check means in the claims of the present application includes a battery check circuit 3, a control circuit 1, and a battery check program stored in the control circuit 1. The microcomputer of the control circuit 1 stores a battery check program and other control programs in addition to a program for controlling the overall operation of the camera.
[0029]
The battery check program performs a battery check operation for determining whether or not the remaining amount of the battery 2 is insufficient by the battery check circuit 3, and when it is determined by this battery check operation that the remaining battery amount is insufficient. The strobe charging circuit of the strobe circuit 4 is operated for a predetermined time at least once, and then the battery check operation is performed again.
[0030]
The power supply terminal Vcc of the microcomputer of the control circuit 1 is connected to the battery 2 via the diode 5 and is supplied with power from the battery 2. The reset terminal of the microcomputer is connected to the battery 2 via the resistor 6, and the microcomputer of the control circuit 1 is reset by being supplied with power from the battery 2 when the battery 2 is loaded into the camera.
[0031]
A strobe circuit 4 and a battery check circuit 3 are connected to the positive electrode of the battery 2, and a strobe circuit 4 and a battery check circuit 3 are connected to the input / output port of the microcomputer of the control circuit 1.
[0032]
The strobe circuit 4 is a well-known type that emits light by discharging the electric charge charged in the main capacitor with an Xe tube. The strobe circuit 4 has a strobe charging circuit that charges the main capacitor with the battery 2 based on a control command from the microcomputer of the control circuit 1 and a Xe tube (xenon tube) by discharging the main capacitor with the control command of the microcomputer. A strobe light emission circuit that emits light, and a charge voltage detection circuit (means for detecting the charge state of the main capacitor) that detects the charge state of the main capacitor of the strobe charging circuit and transmits the detected state to the microcomputer of the control circuit 1 are provided.
[0033]
The battery check circuit 3 includes transistors Q1 and Q2, resistors R1, R2 and R3, and a comparator CMP. The emitters of the transistors Q1 and Q2 are connected to the positive electrode of the battery 2, and the bases of the transistors Q1 and Q2 are control circuits. It is connected to a BCC terminal and a BCL terminal which are set as battery check input / output ports of one microcomputer.
[0034]
The collector of the transistor Q1 is grounded via a resistor R1 as a dummy load. The resistor R1 is a resistor connected to the battery during the battery check, and is switched by the transistor Q1.
[0035]
The collector of the transistor Q2 is grounded via resistors R2 and R3. The series circuit of the resistors R2 and R3 is connected to the positive electrode of the battery 2 via the transistor Q2 so as to be switched by the transistor Q2. The part where the battery voltage VB is divided by the resistors R2 and R3 is connected to the inverting input terminal of the comparator CMP. The comparator CMP is powered from the power supply terminal VCC. The reference voltage Vref output from the constant voltage circuit 6 is input to the non-inverting input terminal of the comparator CMP, and the divided voltage VBC of the resistors R2 and R3 is compared with the reference voltage Vref. The constant voltage circuit for generating the comparator CMP and the reference voltage Vref is integrated into an IC. The output of the comparator CMP is connected to the microcomputer of the control circuit 1.
[0036]
The transistors Q1 and Q2 perform a switching operation when the terminal voltage of the BCC terminal and the BCL terminal of the control circuit 1 becomes L level, and when the voltage VBC at the voltage dividing portion of the resistors R2 and R3 is higher than the reference voltage Vref, The comparator CMP outputs an L level signal to the BCIN terminal for battery check of the microcomputer of the control circuit 1. Further, the comparator CMP outputs an H level signal to the battery check BCIN terminal of the microcomputer of the control circuit 1 when the voltage VBC at the divided portion of the resistors R2 and R3 is lower than the reference voltage Vref.
[0037]
The program for checking the battery of the microcomputer of the control circuit 1 is that the new battery is charged by charging the strobe circuit 4 when the terminal voltage of BCIN is H level because the internal resistance of the new battery is high. Is controlled to activate. This point will be described later.
[0038]
A switch input circuit is connected to the input / output port of the microcomputer of the control circuit 1. In addition to operation switches such as a camera main switch and a release switch, a state detection switch for detecting a state of the camera mechanism such as a back cover switch is connected to the switch input circuit.
[0039]
FIG. 4 shows a part of a conventional battery check operation, and FIGS. 5 and 6 show voltage waveforms of respective parts of the battery check circuit 3 and timing of each signal during the battery check operation shown in FIG.
[0040]
In the battery check operation of FIG. 4, first, the previous battery check flag (BC flag) is reset (step 11). Next, the BCC terminal of the microcomputer of the control circuit 1 is set to L level to turn on the transistor Q2 (step 12). As a result, the series circuit of the resistors R2 and R3 is energized, and a voltage VBC proportional to the battery voltage VB is generated at the voltage dividing portion of the resistors R2 and R3 (see FIGS. 5 and 6).
[0041]
Next, when the BCL terminal of the microcomputer of the control circuit 1 is set to L level, the transistor Q1 is turned on (step 13), and a current flows from the battery 2 to the dummy load resistor R1. This state is continued for 20 msec (step 14). When the dummy load resistor R1 is energized, the battery voltage VB is, for example, from the voltage immediately before the dummy load resistor R1 is energized, assuming that the internal resistance of the battery is 0.5Ω and the current flowing through the dummy load resistor R1 is 1A. Since 0.5 V is dropped, the voltage VBC proportional to the battery voltage VB also has the same waveform (see FIGS. 5 and 6).
[0042]
This voltage VBC is compared with the reference voltage Vref. When the voltage VBC> Vref, the L level is output as the output of the comparator CMP. When the voltage VBC <Vref, the H level is output, and this output voltage is input to the BCIN terminal of the microcomputer of the control circuit 1.
[0043]
When approximately 20 msec has elapsed since the dummy load resistor R1 was energized, the battery check program of the control circuit 1 sets the battery check flag (BC flag = 1) when BCIN = H level (step 16). Thereafter, the BCL terminal and the BCC terminal are set to the H level (steps 17 and 18), the battery check operation is terminated, and the process returns to the main routine.
[0044]
When BCIN = L (battery OK) in step 15, the process proceeds to step 17, the BCL terminal and the BCC terminal are set to H level, the battery check operation is terminated, and the process returns to the main routine.
[0045]
In the main routine, if the battery check flag is not set (when BCF = 0), normal camera operation is allowed. When the BC flag is set (BCF = 1), the battery end is displayed, Operations such as exposure and film winding are prohibited.
[0046]
FIG. 6 shows a battery voltage waveform at the time of battery check when a conventional dry cell containing a slight amount of mercury is used. When the dry battery of FIG. 6 is loaded into the camera of FIG. 1 and the BCC terminal is set to L level, the voltage VBC1 at the voltage dividing portion of the resistors R2 and R3 rises and becomes higher than the reference voltage Vref, and the BCIN terminal becomes L level. Next, when the BCL terminal is set to the L level for a time of 20 msec and the BCL terminal is set to the H level after 20 msec, it becomes flat after the voltage VBC1 at the voltage dividing point decreases, the voltage VBC increases after 20 msec, and the BCIN terminal becomes the H level. become. When the remaining battery level is low and the voltage VBC2 becomes lower than the reference voltage Vref, an H-level output voltage is input from the comparator CMP to the BCIN terminal. Since the battery having the waveform of FIG. 6 maintains a flat waveform when a load is applied, the voltage level output to the BCIN terminal is also stable.
[0047]
However, environmentally friendly batteries that do not contain mercury are now on the market in order to support environmental conservation. This mercury-free battery is not activated and may have a high initial internal resistance. FIG. 5 shows the change in voltage VBC of a battery that does not contain mercury.
[0048]
When the camera battery 2 (see FIG. 2) is a battery that does not contain mercury and is a new battery but has a high internal resistance, as shown in FIG. 5, when the battery 2 is energized to the dummy load resistor R1, There is a region where the voltage drops suddenly immediately after energization, and after that, the characteristics are almost flat. The time during which the voltage is greatly reduced is approximately 10 msec or less although it depends on the magnitude of the current flowing through the resistor R1, which is a dummy load. Therefore, if a battery check is performed within about 10 msec immediately after energization, it is determined that the battery has ended even though it is a new unused battery.
[0049]
Therefore, it is possible to avoid this region where the voltage drops greatly and check the battery in a flat characteristic region, but the voltage is still quite low even in this flat region, so it is usually set as a battery end in the camera. The situation is close to the voltage. For example, in a 3V camera (eg, using two AA batteries), the voltage at the battery end is usually 2 to 2.2 V, although it depends on the load current when the battery is checked.
[0050]
That is, using FIG. 5, when the voltage VBC1 proportional to the battery voltage VB is a high voltage VBC1 (solid line), VBC1> Vref, so the battery voltage is OK, but the low voltage VBC2 (dotted line) ), VBC2 <Vref, so that the battery voltage is insufficient, and the battery OK is not always reliable.
[0051]
In this example, the time during which the dummy load resistor R1 is energized is 20 msec. However, even if the current is energized for several hundreds msec, this waveform basically does not change. The activation inside the battery is not sufficient.
[0052]
In order to sufficiently activate the inside of the battery, the battery check program according to the embodiment of the present invention performs the following operation. As an example, the battery check operation is set so that the battery check program operates when a main switch (not shown) connected to the microcomputer of the control circuit 1 is turned on. This is not a limitation.
[0053]
FIG. 1 shows the flow of the battery check program described above. FIG. 3 shows a waveform of the battery voltage VB when the battery check operation shown in the flowchart of FIG. 1 is performed on a battery that is a new battery but has a large internal resistance, such as a battery that does not contain mercury. .
[0054]
In the flowchart of FIG. 1, steps 51 to 54 are the same as steps 11 to 14 of FIG. 4 and have already been described.
[0055]
In step 55, if BCIN = L (the battery voltage is sufficient when the BCIN terminal is at L level), the process proceeds to step 66, the BCL terminal and the BCC terminal are set to H level, the battery check operation is terminated, and the process returns to the main routine.
[0056]
In step 55, if the BCIN terminal is at the H level (BCIN = H: the battery voltage is insufficient), the BCL terminal and the BCC terminal are set to the H level (steps 56 and 57), and the dummy load resistor R1 is energized once. Then, as shown in FIG. 3, the strobe is charged for 100 msec after a predetermined time t1 msec (step 59).
[0057]
After a predetermined time t2 msec after charging the strobe, the BCC terminal and the BCL terminal are set to L level again to energize the dummy load resistor R1 (steps 61 and 62). After about 20 msec from energization, the microcomputer of the control circuit 1 Check the voltage level of the BCIN terminal.
[0058]
In step 64, if the BCIN terminal is at L level (BCIN = L: battery voltage is sufficient), the process proceeds to step 66, the BCL terminal and BCC terminal are set to H level, the battery check operation is terminated, and the process returns to the main routine.
[0059]
If the BCIN terminal is at the H level in step 64 (BCIN = H: battery voltage is insufficient), the BC flag (battery check flag) is set (BCF = 1) (step 65). With this BC flag set (BCF = 1), it is determined that the remaining battery level is low as a result of the battery check, and the battery end indication is displayed on the liquid crystal display of the camera or the like to indicate “battery end”. , Prohibit camera operation. In the case of the battery OK, BCF = 0 is maintained. After setting BCF = 1, the BCL terminal and the BCC terminal are set to the H level (steps 66 and 67), the battery check operation is terminated, and the process returns to the main routine.
[0060]
If the battery capacity is actually consumed and the battery is near the end of its life, the voltage is lower than the judgment level in the first battery check. It is determined that the battery is exhausted.
[0061]
In the above embodiment, the time t1 from the first battery check to the start of the strobe charge and the time t2 from the end of the strobe charge to the second battery check are several milliseconds to the extent that the camera release sequence or the like is not delayed. What is necessary is just to determine suitably in several tens of msec. In this embodiment, the energization time to the strobe charging circuit is set to 100 msec. However, taking into account the main capacitor capacity of the strobe of the target camera, the characteristics of the charging circuit used, battery variations, etc. Decide.
[0062]
According to the battery check means of the camera of the above-described embodiment, as shown in FIG. 3, in the first battery check by energizing the dummy load resistor R1, the voltage VBC at the divided portion of the resistors R2 and R3 is used. Even if the voltage becomes lower than the reference voltage Vref, the battery is activated by the strobe charging, and therefore becomes higher than the reference voltage Vref in the second battery check.
[0063]
That is, when it is determined that the remaining battery level is insufficient, the strobe charging circuit of the strobe circuit 4 is charged at least once, and then the battery is checked again. In this way, even when a new and unused battery with a high internal resistance is loaded into the camera, it is possible to prevent problems such as being judged as a battery end even when a new battery is loaded and the camera not operating. .
[0064]
If it is determined that the activation of the battery is not necessary in the first battery check operation, the strobe circuit 4 is not charged, and the strobe is charged every time the battery check operation is performed (battery activation). This eliminates the problem that power is wasted and the time lag from when the release button is pressed until the shutter is released increases and the user loses the shutter chance.
[0065]
Furthermore, the merit of this method is that the battery is fully activated and the circuit scale is small because the strobe charging is performed as a battery activation method without adding new parts. The camera is advantageous for cost reduction, and can be applied to most cameras having a control means such as a microcomputer and a strobe. The energy charged in the strobe circuit 4 also becomes part of the energy when the strobe light is emitted by actually performing the exposure operation, so it is not wasted.
[0066]
The above-described battery check operation is set so that the battery check operation is performed when the main switch of the camera is turned on. Of course, the battery check operation is not limited to when the main switch of the camera is turned on.
[0067]
For example, when the microcomputer of the control circuit 1 is activated from the low power consumption mode in which the clock oscillation circuit or the like is not operated to a photographing enabled state by a switch operation or a sensor being turned on, the above-described battery check operation is performed. It may be.
[0068]
In this way, when the battery check operation is performed unconditionally when the main switch is turned on, a new battery with high internal resistance is inserted into the camera, so even if it is determined that the remaining battery power is insufficient, Since the new battery is activated in a short time by charging, it is possible to reduce the probability that the camera will not operate due to the battery NG during the release sequence from when the release button is pressed until the shutter is released.
[0069]
The battery check operation described above may be performed unconditionally when a battery is inserted in the camera and a power-on reset is applied to the control means.
[0070]
In this way, it is possible to reduce the probability that the first battery check after replacement with a new battery having high internal resistance becomes the battery NG during the release sequence after the release button is pressed.
[0071]
Alternatively, the battery check operation may be performed unconditionally when the control means including a microcomputer or the like is activated from the so-called low power consumption mode in which the clock oscillation circuit or the like is not operated to a photographing enabled state by a switch operation.
[0072]
Further, when a main switch of a camera (not shown) is turned on, the battery check operation of FIG. 1 may be performed after charging for a predetermined time regardless of the charging state of the main capacitor of the strobe circuit 4. .
[0073]
In relation to the charging of the main capacitor of the strobe circuit 4, when the camera is activated from the low power consumption mode to the photographing enabled state by the switch operation, it is predetermined regardless of the charging state of the main capacitor of the strobe circuit 4. The battery check operation of FIG. 1 may be performed by performing time charging.
[0074]
In this way, when the main switch is turned on or when the camera is activated from the low power consumption mode to the photographing enabled state, charging is performed for a predetermined time regardless of the charging state of the main capacitor of the strobe. Since the battery has been activated several times by charging, even if a battery check is performed during the release sequence, the probability of occurrence of a release time lag due to strobe charging can be reduced.
[0075]
Furthermore, when a battery is inserted into the camera and a power-on reset is applied to the microcomputer of the control circuit 1, charging may be performed for a predetermined time regardless of the charging state of the main capacitor of the strobe circuit 4.
[0076]
In this way, when a new battery with high internal resistance is loaded in the camera and a power-on reset is applied to the microcomputer, if the charging is performed for a predetermined time regardless of the charging state of the main capacitor of the strobe, this charging is performed. Thus, even if the first battery check is performed during the release sequence, it is possible to reduce the probability that a time lag of the release sequence due to strobe charging will occur.
[0077]
【The invention's effect】
According to the camera of the present invention, when it is determined that the remaining battery level is insufficient, the strobe charging circuit of the strobe is charged at least once, and then the battery check is performed again. Even when a new and unused battery with a high internal resistance is loaded into the camera, such as a compatible battery, it is determined that the battery has ended even though a new battery is loaded, or the camera does not operate. You can prevent problems.
[Brief description of the drawings]
FIG. 1 is a flowchart of a battery check operation of a camera according to an embodiment of the present invention.
FIG. 2 is a block circuit diagram of a camera that performs a battery check operation of FIG. 1;
FIG. 3 is a waveform diagram of a battery voltage VBC that changes due to the battery check operation of FIG. 1;
FIG. 4 is a flowchart of a conventional battery check operation in a camera having the block circuit of FIG.
FIG. 5 is a waveform diagram when the conventional battery check operation of FIG. 4 is performed in an environment-friendly battery that does not use mercury.
FIG. 6 is a waveform diagram when the conventional battery check operation of FIG. 4 is performed in a conventional dry battery containing mercury.
[Explanation of symbols]
1 Control circuit (control means)
2 battery
3 Battery check circuit
4 Strobe circuit

Claims (8)

A strobe charging circuit for charging a main capacitor for strobe emission with a battery, a battery check means for comparing the voltage of the battery with a reference voltage, a comparison result of the battery check means while controlling the battery check means and the strobe charging circuit And a control means for determining a battery end of the battery based on the camera, and performs a battery check operation,
The battery check means includes a dummy load, and a switching transistor for passing current to the dummy load by the battery,
The battery check operation is
A dummy load is energized for a predetermined time by the switch transistor, and the battery check means compares the voltage of the battery at this time with the reference voltage,
When the battery voltage is higher than the reference voltage, it is determined that the remaining battery level is sufficient,
When the battery voltage is less than or equal to the reference voltage, after the predetermined time has elapsed, the strobe charging circuit charges the main capacitor for a certain period of time,
After the lapse of a certain time, a dummy load is energized for a predetermined time by the switch transistor, and the battery check means compares the voltage of the battery at this time with the reference voltage,
A camera characterized in that when the voltage of the battery is equal to or lower than the reference voltage, it is determined that the battery is at the battery end, and when the voltage of the battery is higher than the reference voltage, it is determined that the remaining amount of the battery is sufficient .   2. The camera according to claim 1, wherein the battery check unit performs the battery check operation when a main switch of the camera is turned on. 2. The camera according to claim 1, wherein the control means has a low power consumption mode and a shootable mode, and the battery check means when the control means is switched from the low power consumption mode to the shootable mode. Performs the battery check operation. A camera according to claim 1, wherein, a camera, characterized in that when the power ON reset is applied to the control means the battery is placed, said battery check means performs the battery check operation. 2. The camera according to claim 1, wherein when the main switch of the camera is turned on, the control means performs charging regardless of a charging state of a main capacitor of the strobe charging circuit. 2. The camera according to claim 1, wherein the control unit has a low power consumption mode and a shootable mode, and when the shootable mode is activated from the low power consumption mode, the control unit is configured to use the strobe charging circuit. A camera characterized by charging regardless of the state of charge of the main capacitor. Performed in the camera according to claim 1, wherein, when the battery power ON reset is applied to the control means is loaded in the camera, the irrespective charging state of charge of the main capacitor of the control means the flash charging circuit A camera characterized by that. A strobe charging circuit for charging a main capacitor for strobe emission with a battery, a battery check means for comparing the voltage of the battery with a reference voltage, a comparison result of the battery check means while controlling the battery check means and the strobe charging circuit Control means for determining the battery end of the battery based on the above, and means for detecting the charged state of the main capacitor, the control means is a camera that performs a battery check operation when the main switch is turned on. ,
The battery check means includes a dummy load, and a switching transistor for passing current to the dummy load by the battery,
The battery check operation is
A dummy load is energized for a predetermined time by the switch transistor, and the battery check means compares the voltage of the battery at this time with the reference voltage,
When the battery voltage is higher than the reference voltage, it is determined that the remaining battery level is sufficient,
When the voltage of the battery is equal to or lower than the reference voltage, after the elapse of the predetermined time, the strobe charging circuit charges the main capacitor for a time corresponding to the charging state of the main capacitor,
After the lapse of a certain time, a dummy load is energized for a predetermined time by the switch transistor, and the battery check means compares the voltage of the battery at this time with the reference voltage,
A camera characterized in that when the voltage of the battery is equal to or lower than the reference voltage, it is determined that the battery is at the battery end, and when the voltage of the battery is higher than the reference voltage, it is determined that the remaining amount of the battery is sufficient .

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