JP2962514B2 - Electronic imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electronic imaging device, more specifically, an electronic imager (photoelectric conversion element) that is used for both obtaining a video signal and other purposes. The present invention relates to a control device for a power supply system in an imaging device.

[Related Art] In recent years, electronic imaging devices such as still video cameras and camcorders have been commercialized and used. These apparatuses are equipped with various automation functions so that ordinary users can use them. The automatic functions include, for example, automatic exposure control (hereinafter, referred to as AE), automatic focusing adjustment (hereinafter, referred to as AF), and automatic white balance adjustment (hereinafter, referred to as AWB). As the sensor means, the imager for imaging is also used, and improvement in accuracy, miniaturization, and cost reduction are being attempted.

On the other hand, the power supply of the above-mentioned still video camera or camcorder is often a battery power supply, and therefore, it is necessary to give sufficient consideration to its power saving. First, an example of the power supply system in the case of the conventional still video camera will be described. Seventh
This will be described with reference to the block diagram of FIG. In the drawing, a wide line indicates a power supply line of a power supply, an outline wide line indicates an imaging signal line, and a solid line indicates a control signal line. Also, the first
The same applies to FIG. 5 and FIG.

The camera controls each control circuit for processing timing, adjustment of an imaging signal, adjustment of a recording signal, and the like by a system control circuit 7. The imaging signal output from the imager 9 is sampled and held by a process circuit 50. Processing, color difference signal processing, and the like are performed, and the luminance signal and the color difference line-sequential signal are input to the recording circuit system 13. Then, modulation and addition processing are performed, and the video output signal is input to the recording unit of the FDD 14 which is a floppy disk drive device, and recording is performed. A synchronization signal generation circuit SSG circuit 8 controlled based on an instruction from the system control circuit 7 gives a control synchronization signal to the imager 9, the process circuit 50, the recording circuit system 13, and the FDD 14.

An AE circuit which is controlled by the system control circuit 7 and is an automatic exposure control circuit including an aperture control circuit.
Reference numeral 15 captures the luminance signal of the process circuit 50, obtains photometric data, drives the aperture, and stores the data in the RAM in the system control circuit 7. The AF circuit 16, which is an automatic focusing control circuit including a photographing lens focusing driving circuit,
Focusing degree data is obtained from the luminance signal, and the lens is driven for focusing. In addition, an automatic white balance circuit
The AWB circuit 17 obtains color temperature data of the subject based on the luminance and color difference signals, and stores the data in a RAM in the system control circuit 7 for white balance correction.

The output signal of the trigger switch 18 having the built-in one- and two-stage switches SW5 and SW6 for performing the preparation and start commands for photographing is input to the system control circuit 7. Further, the output terminal of the stabilization circuit 20 to which the power supply 19 for driving the device is connected, one is connected to the power supply system V _DD0 , and the other is
They are connected to the power supply system V _DD1 via 51, respectively. The ON / OFF of the SW 51 is controlled by the power supply control signal VCT ₁ of the system control circuit 7.

The power supply system V _DD0 is a system in which a predetermined voltage is constantly applied in order to maintain a standby state of the device, and is connected to a power supply unit of the system control circuit 7. A power supply system V _DD1 is connected to power supply terminals of control circuit elements such as the imager 9 except the system control circuit 7. In response to the ON signal of the first-stage trigger SW5 of the trigger switch 18, SW51 is turned on, and the power supply system V
_The power supply voltage is output to _DD1 .

FIG. 8A illustrates the operation of the conventional camera configured as described above in the power supply state. FIG. 8A shows the change in the power consumption of the camera corresponding to the operation of the trigger switch 18. _Power is always supplied only to the power supply system V _DD0 , and when SW5 is turned on by pressing one step (point A in FIG. 8 (A)), a power supply control signal VCT ₁ is output and supplied to the power supply system V _DD1 . A power supply voltage is applied, and all control circuits below the imager are in an operating state, that is, a state of waiting for photographing. Then, when SW6 is turned on by a two-step push at a desired photo opportunity (point C in FIG. 8A), shooting is started. When the writing of the video signal is completed FDD14, D of the feed control signal VCT ₁ is turned off, the power feeding to the power feeding system V _DD1 is stopped (FIG. 8 (A)
point). Therefore, until the Figure 8 (A) to the elapsed shooting the latency first stage consists of pressed as shown is finished, the power consumption is substantially constant value W _1.

[Problems to be Solved by the Invention] However, in the above-described conventional power supply system for a camera, the control circuit which does not need to be always in the operating state during the waiting time for shooting as described above always supplies the power supply voltage. Works, and wastes power. For example, A
Measurement circuits such as E, AF, and AWB do not hinder the operation of these circuits once they perform measurement and control operation or data fetching by pressing the trigger one step. . Further, the recording circuit system 13 or the process circuit 50
Some of the circuits need not be in an operating state except during recording of a video signal. As described above, in the above-described system of the related art, a large amount of power is wasted during the period of waiting for photographing, which is extremely disadvantageous in terms of power saving.

To describe this problem in detail, first, in an imaging device in which the automation function devices such as AF, AE, and AWB are based on independent sensors, each power supply system is also independent, and each system is independent. It was easy to control the power supply. However, in a system in which the same imager is used as a sensor as described above, the conventional device does not have an independent power supply system, and thus it is difficult to independently control each system as described above. Was.

Further, in a conventional system in which the same imager is also used as various sensors, problems such as an increase in the number of switch elements based on the separation of the power supply system, an increase in the complexity of the substrate pattern, or an increase in cost are caused. Therefore, some or all of the power supply system must be integrated. Therefore, there is a problem that a large power loss occurs for a long time in the operation of the imaging apparatus.

An object of the present invention is to divide the power supply system into a plurality of parts in order to solve the above-mentioned problem, to control power supply or power supply stop for each system during the time section, and to apply an input signal in an unpowered state. An object of the present invention is to provide an electronic imaging device provided with a means for preventing a circuit from being destroyed.

[Means and Actions for Solving the Problems] An electronic imaging apparatus according to the present invention is provided so that the same imager is also used as a sensor for a plurality of purposes including a purpose of obtaining a video signal and other purposes. And a plurality of power supply systems divided for each circuit corresponding to each of the plurality of objectives or a circuit block corresponding to a combination of the plurality of objectives, and the plurality of power supply systems which do not always need to supply power at the same time. A predetermined power supply system of the system includes means for selectively stopping power supply during a corresponding time section, and a buffer means for preventing circuit destruction even when an input signal is applied in an unpowered state is provided as described above. It is provided before a circuit or a circuit block.

Hereinafter, the present invention will be described with reference to the illustrated embodiments.

FIG. 1 is a block diagram showing an electric circuit of a still video camera which is an electronic image pickup apparatus according to a first embodiment of the present invention. The above-mentioned camera has substantially the same configuration as that of the camera of the conventional example, but the difference will be described. First, the process circuit is divided into a process circuit I10 and a process circuit II11 in order to divide the power supply system. The process circuit I10 performs sample hold processing, color signal processing, and the like, and outputs a luminance signal and a color difference signal. Then, the subsequent process circuit II11 generates a color-difference line-sequential signal to be an input signal of the next-stage printing circuit.

The process circuit II11 has a built-in buffer circuit 11a at its input end as shown in FIG. 2, and the input end of the process circuit II11 may have a high impedance configuration when the power supply voltage V _DD3 is not applied. You can do it. This is because, in the inoperative state described above, when the power supply voltage V _DD2 acts and the process circuit I10 is activated, if the buffer circuit 11a is not provided, the AE, A of the process circuit I10
F, output to AWS circuit becomes unstable or process circuit I
There is a danger of malfunction of I11 or destruction of elements, and this is to prevent it.

The power supply control signals VCT ₁ , VCT ₂ , and VCT ₃ output from the system control circuit 7 control ON / OFF of the power supply switch elements SW 1, SW 2, and SW 3 provided at the output unit of the stabilization circuit 20. . Output terminals of these switches are connected to power supply systems V _DD1 , V _DD2 , and V _DD3 , respectively.
The power supply system V _DD1 connects the SSG circuit 8 to the power supply terminal of the FDD 14,
_Power supply system V _DD2 is imager 9, process circuit I10, AE circuit 1
5, the power supply terminals of the AF circuit 16 and the AWB circuit 17, and the power supply system _VDD3 is connected to the power supply terminals of the process circuit II11 and the recording circuit system 13, respectively.

The system control circuit 7 controls the output timing of the clock output from the SSG circuit 8 to each circuit unit. That is, only when the VCT ₁ is V _DD1 is supplied with ON FDD1
4 to output the clock, VCT ₂ is output to the viewing process circuit I10 when V _DD2 is supplied with ON, V _DD3 seen process circuit II11 when supplied outputs the clock to the recording circuitry 13.

The power supply system of the camera according to the present embodiment configured as described above will be described with reference to the flowchart of FIG. 3 and the time chart of FIG. When the switch SW5 of the first-step trigger of the trigger switch 18 is detected in step S1 (fourth step).
(Point A in the figure), the power supply control signal in step S2
VCT ₁ is turned on, power supply SW1 is turned on, power is supplied to the power feeding system V _DD1, FDD14 the SSG circuit 8 is activated. FDD14 of the spindle motor in step S3, S4 is started, if it is output lock signal for motor control reaches a predetermined speed, the process to step S5 proceeds, the feed control signal VCT ₂ is turned on. And
When the power supply SW2 is turned on, power is supplied to the power supply system _VDD2 , and the imager 9, the process circuit I10, the AE circuit 15, and the A
The F circuit 16 and the AWB circuit 17 are activated. Then, the aperture is controlled based on the AE photometric data, and the data is stored in the RAM for setting the charge conversion time of the imager 9 (step S6). Subsequently, a focusing operation of the lens is performed based on the AF distance measurement data (step S
7). Further, the AWB data, that is, the subject color temperature data is stored in the RAM for white balance adjustment of the color difference signal (step S8).

Next, in step S9, counting of a Tc (second) timer is started. Then, ON / OFF determination of the second-stage trigger SW6 is performed, and if it is ON, the process proceeds to step S17. 2-stage trigger S
If W6 remains off, jump to step S11,
A determination is made as to whether the first-stage trigger SW5 is on or off. If it is off, the power supply control signals VCT ₁ and VCT ₂ are turned off and the process returns to step S1 (step S20). If the above SW5 is ON, in step S12, a time-check overflow of the Tc timer is checked.
Return to 0. SW6 off orゝpredetermined time Tc, for example, after two seconds (a time chart in Tc display portion of FIG. 4), and turns off the control signal VCT ₂ since it is not necessary at this point the power supply of the power supply system V _DD2, The power supply to the power supply system V _DD2 is stopped (step S13). Then, the checks of step S14 and step S15 are repeated until the above-mentioned SW6 is turned on and as long as the SW5 is turned on. If the middle SW5 is turned off, step turns off the control signal VCT ₁
The process returns to S1 (step S21). When two-stage trigger SW6 are turned on, the control signal VCT ₂ is turned on (step S1
6) Then, the process proceeds to step S17, where the control signal VCT ₃ is also turned on, and the switches SW2 and SW3 are turned on to supply power to the power supply systems V _DD2 and V _DD3 (point C in FIG. 4).

Then, the imaging signal captured by the imager 9 in step S18 is recorded as a video signal in the FDD 14. After recording ends, the control signal VCT _1, VCT _2, VCT ₃ is turned off in step S19, power supply system V _DD1, V
_DD2 and _VDD3 are turned off, and the shooting sequence ends (point D in FIG. 4).

A diagram of power consumption in the photographing sequence of the camera according to the present embodiment will be described with reference to FIG. Although the power consumption of the conventional example is the time interval A~D is ho Isuzu constant value W _1, in the present embodiment, inter-segment A~C is less value W ₂ than W _1. Therefore, power saving is performed correspondingly. In this embodiment, A to C in FIG.
Although there is a variation in power between them, it is omitted because it is not as large as the difference between C and D.

As described above, in the case of the camera according to the present embodiment, the power supply to the FDD 14 and the like, the power supply to the FDD 14 and the like, the power supply to the color temperature measurement control circuit, and the like are stopped during the time period corresponding to the operation of the trigger switch 18. , And power supply to the recording circuit system and the like are stopped and performed at required timing to save power.

Next, a still video camera which is an electronic image pickup apparatus according to a second embodiment of the present invention will be described with reference to a block diagram of an electric circuit shown in FIG.

The present embodiment is different from the first embodiment in that the number of divisions of the power supply system is further increased and those power supply systems are selected in a time section during operation, thereby improving the power saving effect. First, the process circuit is divided into a process circuit I40, a process circuit II41, and a process circuit III42. Process circuit I4
“0” performs the sample-and-hold processing of the imaging signal output from the imager 9. The output is also input to the AE circuit 15 and the AF circuit 16. Process circuit II41 is a process circuit
A luminance signal and a color difference signal are generated based on the output of I40.
Then, the output is also input to the AWB circuit 17. The process circuit III42 generates a color difference line-sequential signal based on the output of the process circuit II41, and the output is input to the recording circuit system 13 at the next stage. The process circuit II41 and the process circuit III42 each include the buffer circuit shown in FIG. 2 and are configured so that malfunction does not occur even if power is not supplied to each process circuit at the same time.

Regarding the power supply system of the power supply, the output of the stabilization circuit 20 is branched, and the power supply system V _DD0 is _sent to the system control circuit 7.
Power supply system V _DD31 is to SSG circuit 8 and FDD14, also power supply system V
_DD32 is imager 9, process circuit I40, AE circuit 15, and AF
To the circuit 16 and the power supply V _DD33 is connected to the process circuits II 41 and A
To the WB circuit 17, a power supply system _VDD34 is connected to a power supply line to the process circuit III42 and the recording circuit system 13, respectively. The power supply control signals VCT ₃₁ , VCT ₃₂ , VCT ₃₃ , VCT ₃₄ for controlling the power supply on / off are supplied to the power supply systems V _DD31 , V _DD
DD32, V _DD33, V _DD34 is powered switch for turning on and off the SW
31, SW32, SW33 and SW34 are controlled.

The power supply operation in the shooting sequence of the camera according to the present embodiment configured as described above will be described with reference to the time chart of FIG. At all times, the power supply system V _DD0 is in a power supply state, and when SW5 of the first-stage trigger is turned on (A in FIG. 6).
Point), the control signal VCT ₃₁ is turned on, and the power supply system V
Power is supplied to _DD31 , and the spindle motor is started. Then, when it is detected that the predetermined speed has been reached (point B in FIG. 6), the power supply control signal VCT ₃₂ is turned on, the power supply system V _DD32 is in a power supply state, and the AE circuit 15,
The AF circuit 16 operates. Then, the feed control signal VCT ₃₃ is turned on, power supply system V _DD33 is powered state when the metering-focusing operation is finished. Therefore, the color temperature measurement is executed by the AWB circuit.
The system V _DD33 is in an off state until each data measurement by each of the circuits is completed, and power saving is performed during that time.

After the above color temperature measurement, for a time Tc, for example, 2 seconds,
If there is no two-step trigger operation, the power supply control signal VCT ₃₃ is turned off to save power, and the power supply systems V _DD32 and V _DD33 are stopped. When SW6 of the second stage trigger is turned on (point C in FIG. 6), the power supply control signals VCT ₃₂ and VC
T ₃₃ and VCT ₃₄ are turned on, respectively, and the power supply system V _DD32 ,
Power is supplied to V _DD33 and V _DD34 . When the recording of the video signal is completed in the _{FDD 14} , the power supply to the power supply systems other than the power supply system _VDD0 is cut off.

As a modified example of the camera power supply system of the second embodiment, the power supply system V _DD32 in the block diagram of FIG.
A method of independently supplying power to 0 is conceivable. This variant is called A
By separately supplying power to the measurement circuits of the E-AF and the AWB, power saving of a camera having a single function such as measurement of white balance or measurement of photometry or distance measurement data is realized.

Next, as a third embodiment of the present invention, a still video camera that realizes power saving by performing power supply and stop of a power supply system in a manner divided into time sections in which a power supply amount is different during an imaging sequence. Will be described.

The block diagram of the camera of this embodiment may be the one shown in FIG. 7 shown as a conventional example. First, the power supply system V _DD0 is always in a power supply state. And SW5 of one-step trigger
There When turned on (A point of FIG. 8 (C)), the feed control signal VCT ₁ is turned on, power supply system V _DD1 is powered state. AE, AF, feed control signal VCT ₁ when the measurement data was captured is turned off by the respective circuits of the AWB, (B point in FIG. 8 (C)) in which the feeding is stopped.
Until SW6 of the two-stage trigger is turned on, the power supply is kept stopped, so that the power saving effect is large. The power supply is restarted at the point when the two-stage trigger SW6 is turned on (point C in FIG. 8 (C)), and after capturing and recording of the image pickup signal, power supply to the power supply system V _DD1 is performed. Is stopped (point D in FIG. 8 (C)). As shown in FIG. 8 (C), the manner of change in power consumption in this case is as shown in FIG. 8 (C), in which the power supply amount, that is, the power consumption is different between time sections BC and C, that is, the power consumption is different. Since the section where is zero is provided, it is understood that the camera has a more power-saving effect as compared with the cameras of the first and second embodiments. Note that the above time sections B to C
Although the case where the power consumption is 0 is shown during the period, it is needless to say that the power consumption may not be 0.

In the camera of the third embodiment, power is supplied to all the control circuits in the camera operation time periods A and B. As a modified example, AE and A are supplied in the time periods A and B.
A configuration in which only the measurement circuits such as F and AWB are operated can be considered, and the power saving effect can be further improved. The change in power consumption in this case is shown in FIG. 8 (D).

The method of dividing the power supply system shown in each of the embodiments and the modifications described above shows one example, and in addition, a division method suitable for the purpose is performed.
It is also possible to increase the power saving effect.

[Effects of the Invention] As described above, the electronic imaging device according to the present invention includes:
Divide the power supply system or power supply time section into multiple
In the applicable time section, power supply or power supply stop is selected for each system or for each time section, and according to the present invention, power is not supplied to circuit blocks or time sections that do not necessarily need to be supplied simultaneously, A device having remarkable features such as enabling power saving can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electric circuit when the idea is embodied in the form of a still video camera as a first embodiment of the present invention. FIG. 2 is a block diagram of the still video camera of FIG. FIG. 3 is a flowchart of a photographing sequence of the still video camera of FIG. 1; FIG. 4 is a power supply control in the photographing sequence of the still video camera of FIG. 1; FIG. 5 is a block diagram of an electric circuit of a still video camera according to a second embodiment of the present invention, and FIG. 6 is a power supply control in a shooting sequence of the still video camera of FIG. FIG. 7 is a block diagram of an electric circuit of a still video camera as a conventional device, and FIG. FIG. 8B is a diagram showing a change in power consumption in the shooting sequence of the still video camera in FIG. 7, FIG. 8B is a diagram showing a change in power consumption in the shooting sequence in the still video camera in FIG. FIGS. 7C and 7D are diagrams showing changes in power consumption in the shooting sequence of the still video camera according to the third embodiment of the present invention and its modification. SW1,2,3,31,32,33,34 ... means for stopping power supply VDD0, VDD1, VDD2, VDD3 ... power supply system VDD31, VDD32, VDD33, VDD34 ... power supply system

Claims (1)

(57) [Claims] 1. A device adapted to serve as a sensor for a plurality of purposes including a purpose of obtaining a video signal and other purposes using the same imager, wherein each circuit corresponding to the plurality of purposes is provided. A plurality of power supply systems divided for each circuit block corresponding to the combination of the plurality of objectives, and a predetermined power supply system of the plurality of power supply systems that do not always need to supply power at the same time section. Means for selectively stopping power supply, wherein buffer means for preventing circuit destruction even when an input signal is applied in an unpowered state is provided at a preceding stage of the circuit or the circuit block. Electronic imaging device.