JPH11252444A - Image-pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generally save power by avoiding a failure in saving the power due to clock supply and reducing or eliminating the wasteful power consumption of a circuit in an operation unrequired state. SOLUTION: This device is provided with plural circuit blocks 10, 11, 13 and 14, including an image-pickup element circuit as one circuit block, a clock supply means circuit (SSG) 8 for supplying control clock signals to the plural circuit blocks and a system control circuit (clock supply control means) 7, capable of controlling the clock supply means and performing selective clock supply control for stopping the supply of the clock signals to the circuit block without the need of clock supply at the point of time among the plural circuit blocks.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly, to a control device of a power supply system in an image pickup apparatus which uses an imager (photoelectric conversion element) for obtaining a video signal and for other purposes.

[0002]

2. Description of the 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) and the like, and the imager for imaging is also used as a sensor means therefor, 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, camcorder and the like is often a battery power supply.
It is necessary to give sufficient consideration to the power saving. First, an example of a power supply system in the case of a conventional still video camera will be described with reference to a 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.
The same applies to FIG.

[0004] The camera is a system control circuit 7
The control circuit controls each control circuit for processing timing, adjustment of an image signal, adjustment of a recording signal, and the like. The image signal output from the imager 9 is subjected to a sample hold process, a color difference signal process, and the like by a process circuit 50. Then, 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,
The video output signal is input to the recording unit of the FDD 14 which is a floppy disk drive, and recording is performed. The SSG circuit 8 of the synchronizing signal generation circuit controlled based on the instruction of the system control circuit 7 includes the imager 9, the process circuit 50, the recording circuit system 13, and the FDD 14.
Is supplied with a control synchronizing signal.

An AE circuit 15, which is controlled by the system control circuit 7 and is an automatic exposure control circuit including an aperture control circuit, takes in the luminance signal of the process circuit 50, obtains photometric data, and drives the aperture and performs system control of data. The storage in the RAM in the circuit 7 is performed. The AF circuit 16, which is an automatic focusing control circuit including a photographic lens focusing driving circuit, obtains focusing degree data from the luminance signal and performs focusing driving of the lens. Further, the AWB circuit 17, which is an automatic white balance circuit, obtains color temperature data of the subject based on the luminance and color difference signals, and stores the data in the RAM in the system control circuit 7 for white balance correction.

A trigger switch 1 having built-in one- and two-stage switches SW5 and SW6 for performing a photographing preparation and start command.
The output signal of 8 is input to the system control circuit 7. One of the output terminals of the stabilizing circuit 20 to which the power supply 19 for driving the device is connected is connected to the power supply system VDD0 via the power supply system VDD0, and the other is connected to the power supply system V
Each is connected to DD1. Then, the SW 51
Is controlled by the power supply control signal VCT1 of the system control circuit 7.

The power supply system VDD0 is a system in which a predetermined voltage is constantly applied in order to maintain the standby state of the apparatus, and is connected to a power supply unit of the system control circuit 7. Then, except for the system control circuit 7,
A power supply system VDD1 is connected to a power supply terminal of a control circuit element such as the imager 9. And the trigger switch 18
In response to the ON signal of the first-stage trigger SW5, the SW51 is turned on, and the power supply voltage is output to the power supply system VDD1.

The operation of the conventional camera having the above configuration in the power supply state will be described with reference to FIG. 6A. The figure shows a change in the power consumption of the camera corresponding to the operation of the trigger switch 18. is there. Power is always supplied only to the power supply system VDD0, and when SW5 is turned on by pressing one step (point A in FIG. 6A), the power supply control signal V
CT1 is output to apply a power supply voltage to the power supply system VDD1, and all control circuits below the imager enter an operating state, that is, a state of waiting for photographing. Then, when the SW6 is turned on by pressing the shutter two steps at the desired shutter chance (FIG. 6).
(Point C in (A)), shooting is started. And FDD1
When the writing of the video signal is completed in step 4, the power supply control signal VCT1 is turned off, and the power supply to the power supply system VDD1 is stopped (point D in FIG. 6A). Accordingly, as shown in FIG. 6A, the power consumption is substantially constant W1 from the pressing of the first stage to the end of the photographing after a certain waiting time has elapsed.
Becomes

[0009]

However, in the above-described conventional power supply system for a camera, the control circuit which does not need to be always in operation during the waiting time for photographing as described above always supplies the power supply voltage. Works, and wastes power. For example, measurement circuits such as AE, AF, and AWB perform measurement once by pressing a trigger once to complete a control operation or data acquisition.
There is no problem even if those circuits become inoperative. In addition, some circuits of the recording circuit system 13 or the process circuit 50 do not need to be in any particular operation 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, there is a situation that a clock signal is supplied to each part of each circuit block in this type of imaging apparatus. From the viewpoint of reducing the circuit scale and uniform controllability, this clock supply means is often configured as one circuit block like the SSG circuit 8 in the above-described conventional camera. That is,
Since the video signal output from the imager is recorded, the driving of the imager and the subsequent signal processing (including various types of information processing) and recording processing need to be performed in synchronization with each other. Generating a clock is a natural and efficient configuration.

On the other hand, since the clock represented by the imager driving pulse has a high frequency, when the clock is supplied and the circuit is driven, relatively large power consumption occurs in the circuit block. This power consumption often accounts for a large proportion of the total power consumed by the circuit.

As described above, in a camera, there is a circuit that does not need to be in an operating state when focusing on a certain point in time. However, conventionally, since the clock supply is not individually controlled, such a circuit that does not require such an operation is provided. However, it has been difficult to avoid unnecessary power consumption associated with driving by a clock.

[0013] The above-mentioned circumstances related to the clock supply have the following problems. That is, in order to save power, it is convenient if the power supply system is made independent for each circuit block of the camera, and power supply is stopped for the circuits that do not need to operate. However, at that time, if the clock supply to the circuit is continued, the clock supply circuit becomes overloaded, abnormally consumes power, or is further destroyed. Stop was not possible.

An object of the present invention is to avoid a power-saving problem caused by the clock supply and reduce or eliminate useless power consumption of a circuit in an operation-unnecessary state, thereby achieving comprehensive power saving. It is to obtain an imaging device.

[0015]

According to the present invention, there is provided an imaging apparatus comprising: a plurality of circuit blocks each including an image sensor circuit as one circuit block; clock supply means for supplying a control clock signal to the plurality of circuit blocks; A clock supply control means that controls clock supply means and selectively stops supply of the clock signal to a circuit block of the plurality of circuit blocks that does not need clock supply at that time. A power supply unit capable of selectively supplying power to the plurality of circuit blocks, wherein the clock supply control unit does not supply power to the circuit blocks. And means for controlling so as not to supply the clock signal.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below 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 an 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 to divide the power supply system. The process circuit I10 outputs a luminance signal and a color difference signal by performing sample hold processing, color signal processing, and the like. 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 as shown in FIG.
In the non-operation state where the power supply voltage VDD3 is not applied,
Its input terminal can take a high impedance configuration. This is because when the power supply voltage VDD2 is applied and the process circuit I10 is activated in the above-mentioned inoperative state, if the buffer circuit 11a is not provided, the AE, AF, and AWB circuits of the process circuit I10 are not connected. Is unstable, there is a risk of malfunction of the process circuit II11 or destruction of elements, etc., to prevent this.

The power supply control signals VCT1, VCT2, VCT3 output from the system control circuit 7
Controls ON / OFF of SW1, SW2, and SW3, which are power supply switch elements provided at the output unit of the stabilizing circuit 20. Output terminals of these switches are connected to power supply systems VDD1, VDD2, and VDD3, respectively. The power supply system VDD1 uses the SSG circuit 8 as a power supply terminal of the FDD 14, and the power supply system VDD2 uses the imager 9 and the process circuit I1.
0, AE circuit 15, AF circuit 16, and AWB circuit 17
And a power supply system VDD3 is connected to the process circuit I.
I11 and the power supply terminal of the recording circuit system 13 are connected respectively.

Further, the system control circuit 7
The G circuit 8 controls the output timing of the clock output to each circuit unit. That is, a clock is output to the FDD 14 only when VCT1 is turned on and VDD1 is supplied, and VCT2 is output.
ON only when VDD2 is supplied and VDD2 is supplied
0 and the process circuit I only when VDD3 is supplied.
I11, outputs a clock to the recording circuit system 13.

The power supply system for a 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. If it is detected in step S1 that the trigger switch 18 of the trigger switch 18 is turned on (point A in FIG. 4), the power supply control signal VCT1 is turned on in step S2, the power supply SW1 is turned on, and power is supplied. Power is supplied to the grid VDD1,
The FDD 14 and the SSG circuit 8 are activated. In steps S3 and S4, when the spindle motor of the FDD 14 is started and reaches a predetermined speed and a motor control lock signal is output, the process proceeds to step S5, and the power supply control signal VCT2 is turned on. Then, 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, the AF circuit 16, and the AWB circuit 17 are activated. 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 S).
6). Subsequently, a focusing operation of the lens is performed based on the AF distance measurement data (step S7). 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, Tc (second)
Start timing of the timer. And the second stage trigger SW6
Is turned on / off, and if it is on, step S17
Proceed to. If the two-stage trigger SW6 remains off, the process jumps to step S11, where the one-stage trigger SW5 is turned on and off.
The power supply control signals VCT1 and VCT2 are turned off, and the process returns to step S1 (step S20). If the switch SW5 is ON, the process proceeds to step S
At 12, a check is made to see if the Tc timer has timed out, and the flow returns to step S10 until an overflow occurs. If a predetermined time Tc, for example, 2 seconds, elapses while the switch SW6 is off (Tc display portion in the time chart of FIG. 4), power supply to the power supply system VDD2 is not necessary at this time, so the control signal VCT2 is turned off, and the power supply system VDD2 The power supply is stopped (step S13). And the above SW6
Until is turned on and as long as SW5 is turned on, the checks in steps S14 and S15 are repeated. If SW5 is turned off in the middle, control signal VCT1 is turned off and the process returns to step S1 (step S1).
21). When the two-stage trigger SW6 is turned on, the control signal VCT2 is turned on (step S16), and then the process proceeds to step S17, where the control signal VCT3 is also turned on, and the switches SW2 and SW3 are turned on and the power supply systems VDD2 and VDD3 are turned on.
Is supplied with power (point C in FIG. 4).

The image signal captured by the imager 9 in step S18 is recorded in the FDD 14 as a video signal. After the recording is completed, step S1
9, control signals VCT1, VCT2, VCT
3 is turned off, the power supply systems VDD1, VDD2, and VDD3 are turned off, and the shooting sequence ends (point D in FIG. 4).

A diagram of the power consumption in the photographing sequence of the camera according to the present embodiment will be described with reference to FIG. In the case of the conventional example, the power consumption is substantially constant value W in time sections A to D.
Although it is 1, in the case of the present embodiment, the value between the sections A to C is W2 smaller than W1. Therefore, power saving is performed correspondingly. In this embodiment, FIG.
In (B), there is a power fluctuation between A and C, but C to D
It is omitted because it is not as large as the difference.

As described above, in the case of the camera according to the present embodiment, power is supplied to the FDD 14 or the like during the section corresponding to the operation of the trigger switch 18, the stop, the photometry, the distance measurement, the color temperature measurement control circuit, etc. Power supply and stop, and furthermore, power supply and stop to the recording circuit system and the like are performed at required timing to save power.

The method of dividing the power supply system shown in the above-described embodiments and the like is merely an example, and the method of dividing the power supply system according to the purpose is performed.
It is also possible to increase the power saving effect.

[0027]

As described above, the image pickup apparatus according to the first aspect of the present invention can stop the supply of the clock signal to the circuit blocks that do not need to operate, so that unnecessary power consumption in unnecessary circuits can be reduced. It has a remarkable effect that it can be reduced.

Further, in addition to the above, the power supply to unnecessary circuit blocks can be stopped, so that there is a remarkable effect that unnecessary power consumption in unnecessary circuits can be eliminated. ing.

That is, according to the present invention, it is possible to avoid power-saving problems caused by clock supply and reduce or eliminate wasteful power consumption of circuits that do not need to operate.
This has a remarkable effect that an imaging device that achieves overall power saving can be obtained.

[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 one embodiment of the present invention;

FIG. 2 is a buffer circuit diagram incorporated in a process circuit used in the still video camera of FIG. 1;

FIG. 3 is a flowchart of a shooting sequence of the still video camera of FIG. 1,

FIG. 4 is a time chart of a power supply control signal and the like in a shooting sequence of the still video camera of FIG. 1,

FIG. 5 is a block diagram of an electric circuit of a still video camera as a conventional device,

FIG. 6A is a diagram showing a change in power consumption in a shooting sequence of the still video camera in FIG. 5;
(B) is a diagram showing a change in power consumption in the shooting sequence of the still video camera of FIG. 1;

[Explanation of symbols]

VDD0, VDD1, VDD2, VDD3 ... power supply system 7 ... system control circuit (clock supply control means) 8 ... SSG circuit (clock supply means) 10 ... process circuit I (circuit block) 11 ... process circuit II (circuit block) 13 ... Recording circuit system (circuit block) 14: FDD (circuit block) SW1, SW2, SW3: switch (power supply means)

Claims (2)

[Claims] A plurality of circuit blocks each including an image sensor circuit as one circuit block; a clock supply unit configured to supply a control clock signal to the plurality of circuit blocks; An image pickup apparatus, comprising: clock supply control means capable of selectively controlling clock supply for stopping supply of the clock signal to a circuit block that does not need to supply a clock at that time among circuit blocks. 2. A power supply unit capable of selectively supplying power to the plurality of circuit blocks, wherein the clock supply control unit controls the clock signal in a state where power is not supplied to the circuit blocks. 2. The image pickup apparatus according to claim 1, further comprising means for controlling so as not to supply the image data.