Abstract:
A solid-state imaging device includes plural photoelectric conversion means arranged along light receiving surfaces, readout means for reading out signal charge generated in the photoelectric conversion means, a voltage supply means for supplying various levels of voltages to respective units including the photoelectric conversion means and the readout means, a detection means for detecting level change of a prescribed supply voltage in supply voltages by the voltage supply means and a control means for controlling so that the level change is converged when level change of the prescribed supply voltage is detected by the detection means.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present invention contains subject matter related to Japanese Patent Application JP 2006-321432 filed in the Japanese Patent Office on Nov. 29, 2006, the entire contents of which being incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a solid-state imaging device used for various image sensors, particularly, relates to a solid-state imaging device and an imaging apparatus capable of securing efficient operation with respect to load changes at the time of activation and other occasions. 
     2. Description of the Related Art 
     In related arts, a MOS-type solid-state imaging device is known as this kind of solid-state imaging device. In the MOS-type solid-state imaging devices, a solid-state imaging device having a system in which signal charge of a photodiode (photoelectric converter) included in a pixel is read out after the charge is transferred to a detection region using a transfer transistor is known. 
     The MOS-type solid-state imaging device having this system is different from a CCD-type solid-state imaging device, in which a CMOS logic circuit is mounted on the same chip, and pixels are operated by one power source of low voltage which is the same as the logic circuit. Therefore, for example, when the transfer transistor is an n-channel MOS transistor, gate voltage of the transfer transistor in the pixel had two values of 0V and a power supply voltage Vdd. In related arts, negative voltage is applied to the gate of the transfer transistor in order to prevent dark current, thereby achieving improvement of image quality (for example, refer to JP-A-2002-217397 (Patent Document 1)). 
       FIG. 10  is a circuit diagram showing an example of a MOS-type solid-state imaging device in the related art. 
     A MOS-solid-state imaging device  1  includes a sensor unit  3  in which plural pixels  2  are arranged in a matrix manner, a vertical scanning circuit  4  and a horizontal scanning circuit  5  driving the sensor unit  3 , and signal holding circuits  6  receiving signals of pixels  2  of one row in the sensor unit  3 . In  FIG. 10 , the pixels  2  are drawn as 2×2 pixels for convenience, however, many pixels are actually arranged. 
     Each pixel  2  includes a photodiode PD performing photoelectric conversion, a transfer transistor QT transferring signal charge of the photodiode PD to a detection region (floating diffusion) FD, an amplifying transistor QA outputting potential at the detection region FD to a vertical signal line  8 , an address transistor QD selecting a row of the pixel  2  and a reset transistor QR resetting potential of the detection region FD. 
     In the pixel  2 , a gate of the address transistor QD is connected to a vertical selection line  10  from the vertical scanning circuit  4 . A gate of the reset transistor QR is connected to a reset line  11 , and a gate of the transfer transistor QT is connected to a vertical readout line  9 . A load transistor QL having a function of a constant current source is connected to one end of the vertical signal line  8  and the signal holding circuit  6  is connected to the other end thereof. An output signal of each pixel is taken by the signal holding circuit  6  through the vertical signal line  8  and outputted to a circuit of a sequential stage through an OR gate  15  by driving the horizontal scanning circuit  5 . 
     The vertical scanning circuit  4  is provided with three buffer circuits  12 ,  13  and  14  at each pixel row. The buffer circuits  12  and  13  output the power supply voltage Vdd to the vertical selection line  10  or the reset line  11  at the output side when a low-level pulse is inputted from the side of the vertical scanning circuit  4  and output ground voltage to the vertical selection line  10  or the reset line  11  at the output side when a high-level pulse is inputted. 
     In this example, a negative voltage generating circuit  7  (for example, a charge pump circuit) is provided as a means for applying negative voltage to the gate of the transfer transistor QT during a charge storage period. The output of the negative voltage generating circuit  7  is inputted to the buffer circuit  14  connected to the vertical readout line  9 . 
     The buffer circuit  14  outputs the power supply voltage Vdd to the vertical readout line  9  at the output side when a low-level pulse is inputted from the side of the vertical scanning circuit  4  and outputs negative voltage to the vertical readout line  9  at the outside side when a high-level pulse is inputted. 
     Next, shutter operation in the above MOS-type solid-state imaging device  1  is shown in  FIG. 11A  and  FIG. 11B . The operation is divided into a charge storage period and a readout period. All pixels in the same row are processed at the same timing. There are a normal shutter mode ( FIG. 11A ) in which storage and readout are performed by each row with continuous operation and the charge is outputted for the number of rows, and a global shutter mode ( FIG. 11B ) in which, after charge storage of all pixels are performed, readout is performed at each row. In  FIG. 11A  and  FIG. 11B , a reset gate signal is denoted as φR, and a transfer gate signal is denoted as φT. 
     In the normal shutter mode ( FIG. 11A ), first, the photodiode PD and the detection region FD are reset, then, charge storage is started. During the readout period after charge storage is finished, signal charge stored in the photodiode PD is transferred to the detection region FD, signal voltage corresponding to the FD is transmitted to the signal holding circuit  6  by a source follower including the amplifying transistor QA and the load transistor QL. In the global shutter mode, reset is performed by turning on a global shutter signal, and charge storage of all pixels is performed at the same time by turning off the global shutter signal, then, charge storage of all pixels is finished at the same time by a mechanical shutter. The readout period after that is the same as the control sequence of the normal shutter for one row, and this sequence is repeated for the number of rows to output signals of all pixels. 
     Next, a boosting charge pump circuit in the related art is shown in  FIG. 12  (for example, refer to JP-A-6-351229 (Patent Document 2)). 
     As shown in the drawing, the charge pump circuit includes an oscillation circuit  201 , an amplifier  202 , a reference voltage source  203 , switches SW 1  to SW 4 , voltage-dividing resistances R 1 , R 2 , a pump capacitor (pump capacitance) Cp, an output capacitor C OUT , an inverter  204  and the like. A power supply voltage Va by the amplifier  202  is applied to both ends of the pump capacitor Cp through the switches SW 1 , SW 4 , and one end of the pump capacitor Cp is connected to the output capacitor C OUT  through the switch SW 2  and the other end is grounded through the switch SW 3 . 
     Then, charge from the amplifier  202  is charged in the pump capacitor Cp by the oscillation circuit  201 , the inverter  204  and switching operation by the switches SW 1  to SW 4 , and the boosted output is smoothed at the output capacitor C OUT  to be outputted as an output voltage V OUT . 
     In this circuit, the output voltage V OUT  is divided by the resistances R 1 , R 2 , and the divided voltage and a reference voltage V REF1  are compared by the amplifier  202 , and output voltage Va of the amplifier  202  is used as the power supply for the charge pump circuit to perform boosting operation. 
     Though the configuration shown in  FIG. 12  is a circuit configuration of the boosting charge pump, a feedback system using an inverting charge pump amplifier can also be realized by the similar configuration. The inverting charge pump circuit is shown in  FIG. 13 . The same signs are put to components common to the  FIG. 12 . 
     As shown in the drawing, in this circuit, one end of the pump capacitor Cp is grounded through the switch SW 1 , and the other end is connected to the drive voltage Vdd through the switch SW 3 . 
     Then, new voltage values are set to respective reference voltages, and at first, charge is stored in the pump capacitor Cp by connecting between the Vdd and GND with the switches SW  1  and SW  3  as a sequence of switching. After that, the switch SW 4  is connected to the output voltage Va of the amplifier  202  and the reverse end is connected to the switch SW 2  to generate negative voltage output V OUT . 
     SUMMARY OF THE INVENTION 
     However, the related arts shown in  FIG. 10  to  FIG. 13  respectively have the following problems. 
     First, concerning a problem of the image sensor shown in  FIG. 10 , reset operation when charge storage is started to be the problem will be described as follows, focusing on the transfer transistor QT of the pixel  2 .  FIG. 14  is a timing chart of transfer-gate drive pulses applied to the transfer transistor QT from the vertical readout line. 
     First, when starting the reset operation, the reset transistor QR and the transfer transistor QT are turned on by signal pulses Φ R , Φ T  from the reset line  11  and the vertical readout line  9  from the vertical scanning circuit  4  (( 1 ) in the drawing). The photodiode PD and the detection region FD are reset because dark charge is swept out by the operation. Next, at the point of ( 2 ), the reset and transfer pulses Φ R , Φ T  are set to the low level, the transfer transistor is turned off and the charge storage is started. 
       FIG. 15A  and  FIG. 15B  are diagrams showing changes of capacitance load at the time of reset in the charge pump circuit (negative voltage generating circuit). As a specific negative voltage, −1.1V shown in the Patent Document 1 is used in this case. 
     First, at a point before the reset is started, all load of the transfer gate is connected to the charge pump circuit. At the moment when the transfer-gate drive pulse is set to High, the load capacitance of the transfer gate is separated from the negative voltage generating circuit. At this time, load in the output of the charge pump is reduced and output voltage varies slightly, however, the negative voltage generating circuit is separated from the transfer gate, therefore, the problem affecting images does not occur. 
     Next, at the point of ( 2 ), the transfer-gate drive pulse is set to Low and the reset is finished to start charge storage. At this time, a load capacitance CQT of the transfer gate is connected to the negative voltage generating circuit at a time. The load capacitance at this time is for all pixels in the case of the global shutter mode. 
     Therefore, in the configuration of  FIG. 10 , the reset operation before the storage period in the global shutter gives large change of capacitance load (capacitance load for all pixels) to the charge pump circuit, as a result, a value of negative voltage varies. At this time, the negative voltage varies in the direction of a smaller absolute value because the capacitance load increases. The period corresponds to the charge storage period, and it is highly likely to be the image with shading caused by dark current by the voltage change period. 
     Next, a problem of the charge pump circuit in the related arts is that, for example, a sudden output change is responded only by a time constant determined by a feedback loop in the negative feedback control shown in  FIG. 12 , and time for recovery is limited depending on a band in the loop. Therefore, at the time of sudden load change, there is a problem that it takes a long time to recover the voltage change by the charge supplied by the capacitor to a stable level. 
     Also in the inverting charge pump shown in  FIG. 13 , the similar problem to the charge pump shown in  FIG. 12  occurs, that is, it takes a long time until the output voltage returns to the set voltage because the response to the sudden voltage change is limited depending on a band of the amplifier. The operation is shown in  FIG. 17 . 
     First, a negative voltage (for example, −1.1V) is applied to the transfer gates of all pixels at the same time as falling of the global shutter signal, the load as the charge pump increases in a moment. Accordingly, output voltage varies because of the movement of charge from the capacitor, and the amplifier  202  operates to decrease the amplifier output Va for supplying charge. Since the output of the amplifier is connected to the switch SW 4  in  FIG. 13 , the low level of a voltage (CB) switching the pump capacitor operates in the same manner as the output change of the amplifier  202 . According to the above feedback operation, the output voltage converges to the set value. Since the response of the output voltage follows the response of the amplifier, it is difficult to restore the voltage immediately. 
     In order to stabilize operation, large capacitance is used for the output capacitor C OUT . Therefore, it takes a long time to reach a target voltage from the zero start such as the occasion of switching on or returning from a standby state. The operation is shown in  FIG. 16 . 
     The problem of convergence of voltage leads to the delay of negative voltage applied to the transfer transistor being a set voltage, and it is difficult to apply sufficient negative voltage for suppressing dark current, accordingly, a disadvantage of causing shading occurs because the dark current is generated. 
     As a method of solving the above disadvantage, there is a method of widening the band of the amplifier in  FIG. 12  and  FIG. 13 , however, disadvantages such as deterioration of stability or increase of effects of switching noise adversely occur. It can be considered that the external capacitance is increased as another method of reducing change of output voltage, however, the method generates new problems in aspects of space and costs. 
     The length of activation time such as the occasion of switching on or returning from a standby state means that the negative voltage is not stabilized for a long time and it is difficult to obtain a good image for a fixed time, therefore, it is difficult to be the standby state positively, which does not contribute to reduced power consumption. 
     Thus, it is desirable to provide a solid-state imaging device and an imaging apparatus capable of speeding up activation operation and suppressing load change by performing suitable current supply in the occasion of activating the apparatus or in the occasion of sudden load change, thereby realizing speed-up of the operation and low power consumption. 
     According to an embodiment of the invention, there is provided a solid-state imaging device including plural photoelectric conversion means arranged along light receiving surfaces, readout means for reading out signal charge generated in the photoelectric conversion means, a voltage supply means for supplying various levels of voltages to respective units including the photoelectric conversion means and the readout means, a detection means for detecting level change of a prescribed supply voltage in supply voltages by the voltage supply means, and a control means for controlling so that the level change is converged when level change of the prescribed supply voltage is detected by the detection means. 
     According to an embodiment of the invention, there is provided an imaging apparatus including a solid-state imaging device for performing imaging of subjects, an imaging optical system focusing subject images at light receiving portions of the solid-state imaging device, a drive control unit driving the imaging optical system, a signal processing unit performing signal processing of output signals from the solid-state imaging device and generating imaging signals, a recording unit recording imaging signals generated by the signal processing unit, an output unit outputting imaging signals generated by the signal processing unit, and an operation unit inputting various signals for controlling imaging operations, in which the solid-state imaging device includes plural photoelectric conversion means arranged along light receiving surfaces, readout means for reading out signal charge generated in the photoelectric conversion means, a voltage supply means for supplying various levels of voltages to respective units including the photoelectric conversion means and the readout means, a detection means for detecting level change of a prescribed supply voltage in supply voltages by the voltage supply means and a control means for controlling so that the level change is converged when level change of the prescribed supply voltage is detected by the detection means. 
     The solid-state imaging device and the imaging apparatus according an embodiment of the invention detect level change of a prescribed supply voltage by the voltage supply means and performs control so that the level change is converged, therefore, there are advantages such as speed-up at the time of activation or that a sudden load change during operation can be minimum. 
     Therefore, for example, it is possible to allow the solid-state imaging device to be a stand-by state frequently because of the speed-up of activation, thereby realizing low power consumption of equipment. In addition, as a current supply due to the momentary load change, for example, an external capacitance is used. The current supply ability at the time of sudden load change is increased according to an embodiment of the invention, thereby storing charge to the external capacitance quickly, as a result, it is possible to select a smaller external capacitance and to expect improvement in aspects of costs and layout. 
     The voltage supply means includes the charge pump circuit having the pump capacitance pumping up charge from amplifier output and the switching circuit performing switching control of the charge-pump operation by the pump capacitance, and the level change of supply voltage is controlled by controlling switching frequency of the charge pump circuit, thereby performing stable voltage supply. 
     In addition, the control means is allowed to be, for example, a selection circuit switching control signals which control switching frequency of the charge pump circuit, thereby realizing the device with the simple configuration. The control means can be, for example, the voltage control oscillator or the PLL which controls switching frequency of the charge pump circuit, thereby controlling the voltage supply amount with high accuracy and smoothly, or in multistage. 
     Additionally, the detection means is allowed to be the comparator which compares the supply voltage with the prescribed reference voltage, thereby realizing the device with the simple configuration. The detection means can be also an AD converter which digitalizes the supply voltage, thereby realizing the detection with high accuracy and in multistage. 
     Note that optimum means can be selected as the above control means and the detection means according to costs or applications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a circuit diagram showing a charge pump circuit of a solid-state imaging device according to a first embodiment of the invention; 
         FIG. 2  is an explanatory graph showing input and output characteristics of VCO used for the charge pump circuit shown in  FIG. 1 ; 
         FIG. 3  is an explanatory graph showing operation of the charge pump circuit shown in  FIG. 1  at the time of activation. 
         FIG. 4  is an explanatory graph showing operation of the charge pump circuit shown in  FIG. 1  at the time of overload. 
         FIG. 5  is a circuit diagram showing a charge pump circuit of a solid-state imaging device according to a second embodiment of the invention; 
         FIG. 6  is an explanatory graph showing input and output characteristics of VCO used for the charge pump circuit shown in  FIG. 5 ; 
         FIG. 7  is an explanatory graph showing operation of the charge pump circuit shown in  FIG. 5  at the time of activation. 
         FIG. 8  is an explanatory graph showing operation of the charge pump circuit shown in  FIG. 5  at the time of overload. 
         FIG. 9  is a circuit diagram showing a charge pump circuit of a solid-state imaging device according to a third embodiment of the invention; 
         FIG. 10  is a circuit diagram showing a configuration example of a MOS-type solid-state imaging device in the related art; 
         FIG. 11A  and  FIG. 11B  are explanatory graphs showing shutter operations of the solid-state imaging device shown in  FIG. 10 ; 
         FIG. 12  is a circuit diagram showing a configuration example of a boosting charge pump circuit in the related art; 
         FIG. 13  is a circuit diagram showing a configuration example of an inverting charge pump circuit in the related art; 
         FIG. 14  is an explanatory chart showing transfer gate drive pulse applied to the transfer transistor from a vertical readout line shown in  FIG. 10 ; 
         FIG. 15A  and  FIG. 15B  are explanatory diagrams showing capacitance load changes at the time of reset in the charge pump circuit shown in  FIG. 13 ; 
         FIG. 16  is an explanatory graph showing operation of the charge pump circuit shown in  FIG. 13  at the time of activation; 
         FIG. 17  is an explanatory graph showing operation of the charge pump circuit shown in  FIG. 13  at the time of overload; and 
         FIG. 18  is a block diagram showing a configuration example of a camera apparatus using the solid-state imaging device according to an embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a circuit diagram showing a first embodiment of a negative voltage generating circuit (charge pump circuit) of a solid-state imaging device according to an embodiment of the invention. The whole configuration of the solid-state imaging device is the same as the configuration, for example, shown in  FIG. 10 , and the explanation thereof is omitted. In  FIG. 1 , the same signs are put to components common to the related example shown in  FIG. 13 . 
     As shown in the drawing, the charge pump circuit includes a selection circuit  101 , a voltage control oscillator (VCO)  102 , a comparator  103 , an amplifier  202 , a reference voltage source  203 , switches SW 1  to SW 4 , voltage-dividing resistances R 1 , R 2 , a pump capacitor Cp, an output capacitor C OUT , an inverter  204  and the like. 
     The operation as the charge pump is performed in the same manner as  FIG. 13 . First, charge is stored in the pump capacitor Cp by connecting between Vdd and GND by the switches SW 1 , SW 3 . After that, a negative voltage output V OUT  is generated by connecting the switch SW 4  to an output voltage Va of the amplifier  202 , and connecting the reverse end to the switch SW 2 . 
     In  FIG. 1 , the selection circuit  101  is a circuit selecting control voltages V OSC1 , V OSC2  to be supplied to the VCO  102  depending on an output signal from the comparator  102 . 
     The VCO  102  inputs control voltages V OSC1 , V OSC2  selected by the selection circuit  101 , outputting a signal having an oscillation frequency according to the voltage value and supplying the signal to respective switches SW 1  to SW 4  and the inverter  204 .  FIG. 2  is an explanatory graph showing input and output characteristics of VCO  102 . As shown in the drawing, output signals having frequencies in relation to the level of the control voltages V OSC1 , V OSC2  are outputted. 
     The comparator  103  compares the output voltage V OUT  of the charge pump with a reference (threshold) voltage V REF2 , supplying a signal according to the compared result to the selection circuit  101 . 
     Therefore, in this circuit, the oscillation frequency of VCO  102  is switched according to the output voltage V OUT  of the charge pump, and respective switches SW 1  to SW 4  of the charge pump are controlled. 
     Next, specific operations of the charge pump circuit of the embodiment will be explained. 
       FIG. 3  and  FIG. 4  are explanatory graphs showing operations of the embodiment.  FIG. 3  shows the operation at the time of activation and  FIG. 4  shows the operation at the time of overload. 
     First, at the time of activation (V OUT =0V) or in the case of a sudden load change (for example, at the time of global shutter), when the output voltage V OUT  is at a threshold voltage (V REF2 ) or more, a value of the comparator  103  is outputted so as to select the voltage V OSC2  at which the VCO  102  oscillates at high speed. 
     Then, when the V OUT  reaches the threshold voltage (V REF2 ) or less after a certain period of time, the output of the comparator  103  is inverted, the voltage is switched to the voltage V OSC1  at which the VCO  102  oscillates at low speed, namely, a mode is switched to a low power consumption mode which attaches importance to the efficiency. 
       FIG. 5  is a circuit diagram showing a second embodiment of the charge pump circuit. The whole configuration of the solid-state imaging device is the same as the configuration shown, for example, in  FIG. 10 , and the explanation thereof is omitted. In  FIG. 5 , the same signs are put to components common to the embodiment shown in  FIG. 1 . 
     As shown in the drawing, in the charge pump circuit of the embodiment, the comparator  103  is replaced with the AD converter  113 , as well as the selection circuit  101  is replaced with a selection circuit  111  which selects four voltage values V OSC1  to V OSC4 .  FIG. 6  is an explanatory graph showing input and output characteristics of the VCO  102  in the embodiment. As shown in the drawing, output signals having frequencies in relation to the level of the control voltages V OSC1 , V OSC2 , V OSC3 , V OSC4  are outputted. 
       FIG. 7  and  FIG. 8  are explanatory graphs showing operations of the embodiment.  FIG. 7  shows the operation at the time of activation and  FIG. 8  shows the operation at the time of overload. 
     According to the configuration of the embodiment, the output frequency of the VCO  102  can be multi-valued as compared with the case using the comparator  103 . According to multivalued output frequency, it is possible to realize both convergence and high-speed, in which the convergence gets preference by reducing the frequency in the vicinity of a target voltage, and high-speed gets preference by increasing the frequency when the divergence to the target voltage is large. 
       FIG. 9  is a circuit diagram showing a third embodiment of the charge pump circuit. The whole configuration of the solid-state imaging device is the same as the configuration shown, for example, in  FIG. 10 , the explanation thereof is omitted. In  FIG. 9 , the same signs are put to components common to the embodiment shown in  FIG. 5 . 
     As shown in the drawing, in the charge pump circuit of the embodiment, the selection circuit  111  and the VCO  102  are replaced with a PLL  120 , and an output frequency signal of the PLL  120  is variably controlled by a multiply control signal from the AD converter. Generally, it is necessary to correct frequency variations in the VCO due to process variations by using a particular correction method (for example, trimming and the like). The embodiment can be realized not using the particular correction since it is not necessary to use the VCO. As a result, frequency variations are reduced, thereby realizing a system in which band limitation for eliminating noise can be easily performed. In the embodiment, frequency signals generated by the PLL  120  is the same as ones shown, for example, in  FIG. 6 , and operations at the time of activation and at the time of overload are the same as ones shown in  FIG. 7  and  FIG. 8 . 
     In the above explanation, the case in which the embodiment of the invention is applied to the MOS-type solid-state imaging device was explained, however, the invention is not limited to the MOS-type solid-state imaging device and can be applied to solid-state imaging devices such as a CCD image sensor. 
     The solid-state imaging device is not limited to the one in which a CMOS image sensor and the like are included on one-chip, and it is also preferable that it is a module in which an imaging unit, a signal processing unit and an optical system are integrally packaged. In addition, the device can be used in a camera system and a cellular phone. In the embodiments of the invention, the configuration including the function of the CMOS image sensor by itself is called as the solid-state imaging device and the configuration in which the solid-state imaging device and other elements (a control circuit, an operation unit, a display unit, a data storage function, a communication function and the like) are integrally united is called as an imaging apparatus. 
     Hereinafter, an imaging apparatus to which an embodiment of the invention is applied will be explained. 
       FIG. 18  is a block diagram showing a configuration example of a camera apparatus using the CMOS image sensor of the embodiment. 
     In  FIG. 18 , an imaging unit  310  takes images of subjects by using, for example, the CMOS image sensor explained in the above embodiments, outputting imaging signals to a system control unit  320  mounted on a main substrate. 
     The imaging unit  310  generates and outputs digital imaging signals by performing AGC (Automatic Gain Control), OB (Optical Black) clamp, CDS (correlated double sampling), A/D conversion and the like to the output signals of the CMOS image sensor. 
     In the embodiment, an example in which imaging signals are converted to digital signals in the imaging unit  310  and outputted to the system control unit  320  is shown, however, it is also preferable to apply a configuration in which analog imaging signals are transmitted from the imaging unit  310  to the system control unit  320 , and the signals are converted to the digital signals at the side of the system control unit  320 . 
     Specific control operations, signal processing and the like in the imaging unit  310  are provided in various manners from the past, and it goes without saying that they are not particularly limited in the imaging apparatus according to the embodiment of the invention. 
     An imaging optical system  300  includes a zoom lens  301  arranged in a lens barrel, a diaphragm mechanism  302  and the like, focusing subject images at light receiving portions of the CMOS image sensor, which drives respective units mechanically by control of a drive control unit  330  based on instructions of the system control unit  320  to perform control such as automatic focusing and the like. 
     The system control unit  320  is provided with a CPU  321 , a ROM  321 , a RAM  323 , a DSP  324 , an external interface  325  and the like. 
     The CPU  321  transmits instructions to respective units of the camera apparatus by using the ROM  322  and the RAM  323  to control the whole system. 
     The DSP  324  generates picture signals of still pictures or moving pictures according to a prescribed format (for example, a YUV signal and the like) by performing various signal processing to imaging signals from the imaging unit  310 . 
     The external interface  325  includes various encoders, a D/A converter and the like, transmitting and receiving various control signals or data with respect to external elements (in the embodiment, a display  360 , a memory medium  340  and an operation panel unit  350 ) connected to the system control unit  320 . 
     The display  360  is a small display such as a liquid-crystal panel incorporated in the camera apparatus, displaying the imaged pictures. In addition to the small display incorporated in the camera apparatus, it is possible to apply a configuration in which image data is transmitted to an external large display device to display the data. 
     The memory medium  340  is capable of appropriately storing taken pictures, for example, in various kinds of memory cards and the like, which can be exchanged, for example, with respect to a memory medium controller  341 . As the memory medium  340 , in addition to various memory cards, disc media and the like using magnetic or light can be used. 
     The operation panel  350  is provided with input keys for performing various instructions by the user when taking pictures by the camera apparatus. The CPU  321  monitors input signals from the operation panel unit  350  and executes various operation controls based on the inputted contents. 
     The embodiments of the invention are applied to the above camera apparatus, thereby providing an imaging apparatus having high quality which performs proper power supply at the time of activation of the apparatus or at the time of sudden load change and which realizes speed-up of activation operation and suppressing load change. In the above configuration, the combination of unit devices or unit modules to be components of the system or the size of setting can be selected suitably based on circumstances in commercialization of products, and the imaging apparatus according to the embodiments of the invention widely includes various modifications. 
     A solid-state imaging device and an imaging apparatus according to an embodiment of the invention can be applied to, as imaging objects (subjects), not only general pictures such as human beings, landscape and the like but also imaging of particular minute image patterns such as a counterfeit money detector, a fingerprint detector and the like. An apparatus configuration in this case is not the one of general camera apparatus shown in  FIG. 18  but one including a further particular imaging optical system or signal processing system having pattern analysis. Also in such case, operation and effect of the invention can be exerted and accurate image detection can be realized. 
     In the case that a remote system is configured such as a remote medical system, an anticrime monitor, and a personal identification, it is possible to have an apparatus configuration including a communication module connected to the network, namely, wide application can be realized. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.