JP2020148967A - Signal output device and control method thereof, and imaging apparatus - Google Patents

Abstract

To provide a signal output device capable of outputting corresponding to each of three states of the potential while suppressing the increase in the number of input signals.SOLUTION: A PWM (pulse width modulation) signal output device 408 includes an input signal analysis unit 402 that analyzes an input signal according to a given rule. A signal input part 403 acquires a signal from the input signal analysis unit 402 and performs binary detection of High and Low. A signal amplification unit 404 amplifies a signal from the signal input part 403, and a signal output unit 405 outputs the same to a motor 407 from two output terminals. The input signal analysis unit 402 is configured so as to control in three modes which are determined from five statuses of High/Low, Low/High, High/High, Low/Low, high impedance(z)/high impedance(z) as a logical combination concerning the two output terminals of the signal output unit 405 when switching the command for signal amplification unit 404 based on the analysis result of the input signal.SELECTED DRAWING: Figure 7

Description

The present invention relates to a signal output device for driving an actuator in an imaging device or the like.

An image pickup device having an image blur correction function for vibrations such as camera shake includes a device provided with a correction mechanism (hereinafter, also referred to as an image plane vibration isolation mechanism) for moving the image pickup element in parallel. For example, in the case where the drive unit (actuator) is arranged in the vicinity of the image sensor, it is necessary to pay attention to the generation of magnetic noise in the mechanism for moving the image plane by utilizing the magnetic interaction.

Generally, a flat voice coil motor (hereinafter referred to as VCM) is used as an actuator of the mechanism unit. In the case of driving by PWM (pulse width modulation) control, so-called switching noise or magnetic noise as driving noise may occur. The imaging device disclosed in Patent Document 1 has a driver that switches the output of an analog control signal and a digital control signal according to the brightness of the subject at the time of shooting, with the problem of generating noise in PWM drive. On the other hand, if the generation of noise in the PWM drive itself can be suppressed, it is not necessary to use a driver for switching the output as in Patent Document 1.

The output method of the motor driver IC that drives the VCM includes the following methods. The driving voltage of VCM is referred to as VM.
-A method using two potentials, + VM and -VM (hereinafter referred to as forward and reverse energization).
-A method using three potentials of + VM, 0, and -VM (hereinafter referred to as on-short energization).

Japanese Unexamined Patent Publication No. 2011-221319

The ripple current when the drive voltage of the VCM is constant is smaller in the on-short energization than in the forward / reverse energization (details will be described later). Therefore, when it is desired to suppress magnetic noise, it is preferable to use on-short energization.

On the other hand, regarding the number of PWM signals to be input to the motor driver IC, it is one in the forward / reverse energization and two in the on-short energization. In the case of on-short energization, depending on the number of VCMs to be controlled, wiring may become complicated and the number of control ports in a control unit (microcomputer or the like) may increase.
An object of the present invention is to provide a signal output device capable of producing outputs corresponding to each of the three potential states while suppressing an increase in the number of input signals.

The device of the embodiment of the present invention is a signal output device that outputs by pulse width modulation according to an input signal, and is an analysis means for analyzing the input signal and a signal input means for acquiring a plurality of signals from the analysis means. An amplification means for amplifying the signal from the signal input means, and an output means having a plurality of output units and connected to the amplification means. When switching the command to the amplification means according to the analysis result of the input signal, the analysis means is determined from the state of a plurality of signals corresponding to the logical combination of potentials related to the plurality of output units and the state of high impedance. Control is performed in the state, and the output means outputs from the plurality of output units corresponding to the three states.

According to the present invention, it is possible to provide a signal output device capable of producing outputs corresponding to each of the three potential states while suppressing an increase in the number of input signals.

It is a block diagram which shows the central sectional view and the electric structure of the image pickup apparatus of embodiment. It is an exploded perspective view of the image blur correction mechanism part. It is a figure explaining the generation of magnetic flux and the influence on an image sensor. It is a figure explaining the connection of the wiring in the PWM energization system. It is explanatory drawing of the input signal and the output signal in the forward / reverse energization. It is explanatory drawing of an input signal and an output signal in on-short energization. It is a block diagram explaining the structure of the PWM signal output device. It is a figure explaining the analysis example of the input signal analysis part. It is a figure explaining the control example by a PWM cycle determination part. It is a figure explaining the setting control example of a dead zone.

Hereinafter, the signal output device and the imaging device according to the present invention will be described in detail with reference to the drawings. In this embodiment, an example of an image pickup device including a PWM signal output device capable of analyzing one system of input signals and outputting corresponding to each of the three states is shown.

FIG. 1 is a diagram showing a configuration example of the imaging device of the present embodiment. FIG. 1A is a central sectional view schematically showing the image pickup apparatus 1. As an example of the image pickup apparatus 1, an interchangeable lens type camera used by mounting the lens unit 2 on the apparatus main body will be described.

The lens unit 2 includes an imaging optical system 3 including a plurality of lenses and diaphragms. The optical axis of the imaging optical system 3 is indicated by the optical axis 4. The lens system control unit (hereinafter referred to as a lens control unit) 12 can communicate with the control unit in the device main body of the image pickup apparatus 1 via the electrical contact 11.

The device main body of the image pickup device 1 is provided with an image pickup device 6, and a display device 9a is provided on the back surface. The user can observe the subject with the electronic viewfinder (EVF) 9b. The main body of the device includes a blur correction unit 14 that corrects image blur of the captured image, and a blur detection unit 15 that detects the shake of the device due to camera shake or the like. The shutter mechanism 16 is arranged on the subject side with respect to the image sensor 6 and is used for controlling the exposure time.

FIG. 1B is a block diagram showing a main component of an imaging system. The image pickup system includes an image pickup unit, an image processing unit, a recording / reproduction unit, and a control unit. The image pickup unit includes an image pickup optical system 3, an image sensor 6, and a shutter mechanism unit 16. The recording / reproducing unit includes a storage unit 8 and a display unit 9 (FIG. 1 (A): display device 9a, EVF9b). The control unit includes a camera system control unit (hereinafter referred to as a camera control unit) 5, an operation detection unit 10, a lens control unit 12, a lens drive unit 13, a blur correction unit 14, and a blur detection unit 15.

The lens control unit 12 controls the drive of the focus lens, the image blur correction lens, the aperture, and the like via the lens drive unit 13. The image sensor 6 receives light from the subject via the image pickup optical system 3 and the shutter mechanism unit 16, and outputs an electric signal by photoelectric conversion. The image processing unit 7 acquires the image signal output by the image sensor 6 and executes development processing and the like. The image data after image processing is stored in the storage unit 8.

The blur detection unit 15 can detect rotation about the optical axis 4 as a central axis, and detects rotational blur of the imaging device in the pitch direction, yaw direction, and roll direction. For example, runout detection is performed using a gyro sensor or the like, and the runout detection signal is output to the camera control unit 5.

The camera control unit 5 controls the control of the image pickup apparatus 1 and the lens unit 2 according to the operation signal detected by the operation detection unit 10. The camera control unit 5 includes a CPU (Central Processing Unit), and the CPU executes a predetermined program to perform various processes in the imaging system.

The blur correction unit 14 corrects image blur according to a control command from the camera control unit 5. The blur correction unit 14 includes a mechanism unit that moves the image sensor 6 in the translational direction in a plane orthogonal to the optical axis 4 and rotates the image sensor 6 about the optical axis 4 as a central axis. The specific structure will be described later with reference to FIG.

Next, the operation of the image pickup apparatus 1 will be described. The light from the subject is imaged on the image pickup surface of the image pickup device 6 via the image pickup optical system 3. The focus evaluation amount and the exposure amount are obtained from the output signal of the image sensor 6, and the optical adjustment process of the image pickup optical system 3 is executed based on the information. That is, the image sensor 6 is properly exposed, and an image pickup signal corresponding to the subject image is output.

The shutter mechanism unit 16 controls the image sensor 6 to block light by moving the shutter curtain. The shutter mechanism unit 16 includes a light-shielding member (mechanical rear curtain), and the shutter mechanism unit 16 completes the exposure to the image pickup element 6. In the image sensor 6, the processing of the electronic front curtain is performed prior to the traveling of the rear curtain of the shutter mechanism unit 16. This is a process of controlling the timing of exposure start by resetting the electric charge for each line. In the electronic front curtain mode, the exposure control is performed in synchronization with the charge reset operation of the image sensor 6 and the movement of the rear curtain of the shutter mechanism unit 16. Since the technology of the electronic front curtain is known, a detailed explanation thereof will be omitted.

The image processing unit 7 includes an A / D converter, a white balance adjustment circuit, a gamma correction circuit, an interpolation calculation circuit, and the like. For example, the image processing unit 7 performs color interpolation (demosizing) processing from the Bayer array signal acquired from the image sensor 6 to generate color image data, and outputs the recording image data to the storage unit 8. Further, the image processing unit 7 compresses data such as still images, moving images, and sounds. The storage unit 8 includes a non-volatile memory and stores various data including image data. The camera control unit 5 performs a process of storing data in the storage unit 8 and a process of outputting the data read from the storage unit 8 to the display unit 9 and presenting the data to the user.

The camera control unit 5 controls image processing, image processing, recording / playback processing, and the like in response to user operation signals. For example, the operation detection unit 10 detects that the shutter release button is pressed. The first switch is turned on by half-pressing the shutter release button, which is referred to as S1 operation below. Further, when the user pushes the button all the way by pressing the shutter release button fully, the second switch is turned on, which is referred to as S2 operation below. When the camera control unit 5 receives a shooting instruction from the operation detection unit 10 by the S2 operation, it performs drive control of the image sensor 6, image processing, compression processing, and the like, and further displays image information and the like on the screen of the display unit 9. Take control. Further, the operation detection unit 10 detects the operation of the touch panel provided on the display device 9a on the back surface of the main body unit, and transmits the operation instruction of the user to the camera control unit 5.

Next, the operation of the imaging optical system 3 will be described. The camera control unit 5 is connected to the image processing unit 7 and calculates an appropriate focal position and aperture value based on the signal from the image sensor 6. That is, the camera control unit 5 measures the photometry and detects the focal state based on the output signal of the image sensor 6, and determines the exposure conditions (F value, shutter speed, etc.). The camera control unit 5 controls the exposure of the image sensor 6 by aperture control and shutter control. The camera control unit 5 transmits a command signal to the lens control unit 12 via the electrical contact 11. The lens control unit 12 controls the lens drive unit 13 according to a command signal from the camera control unit 5. For example, in a mode for correcting camera shake or the like, the lens driving unit 13 moves a correction lens (shift lens or the like) by a command signal from the camera control unit 5 to the lens control unit 12 based on a signal obtained from the image sensor 6. Image blur correction operation is performed.

By controlling the operation of each part of the image pickup apparatus 1 according to the user operation, it is possible to shoot still images and moving images. When the user gives an instruction to shoot a still image or a moving image using the operation member of the imaging device 1, the camera control unit 5 controls the shooting operation according to the operation signal from the operation detection unit 10. The camera control unit 5 calculates a target value based on the detection signal from the blur detection unit 15, and controls the drive of the blur correction unit 14. That is, the camera control unit 5 is responsible for generating the target value based on the detection signal of the blur detection unit 15 and driving control of the blur correction unit 14. At that time, the camera control unit 5 controls the image blur correction operation according to the shooting conditions, the exposure conditions, and the like.

To briefly explain the flow of drive control of the blur correction unit 14, the user performs an S1 operation, and the operation detection unit 10 detects this to start a shooting preparation operation. Image blur correction is performed by the blur correction unit 14 in order to facilitate the composition determination of the user during the so-called composition-determining aiming operation. That is, the image sensor 6 is driven (moved or rotated) by the control of the blur correction unit 14 based on the detection signal of the blur detection unit 15. After that, the user performs an S2 operation, the operation detection unit 10 detects this, and a shooting operation (image recording operation) is started. At this time, the image sensor 6 is driven by the control of the blur correction unit 14 based on the detection signal of the blur detection unit 15 in order to suppress the image blur of the subject image acquired by the exposure operation. After a certain period of time has passed after the exposure, the image blur correction operation is stopped.

A specific example of the blur correction unit 14 having the image plane vibration isolation mechanism will be described with reference to FIG. The blur correction unit 14 includes an image blur correction mechanism unit and a control circuit unit thereof. FIG. 2 is an exploded perspective view of the image blur correction mechanism unit. The electrical mechanism that controls the image blur correction mechanism is not shown. The vertical direction (Z-axis direction) of FIG. 2 is a direction parallel to the optical axis 4, and the X-axis direction and the Y-axis direction orthogonal to the Z-axis direction are defined. The image blur correction mechanism portion includes a fixed portion and a movable portion. Fixed parts that do not move are numbered in the 100s, and moving parts are numbered in the 200s. The balls 301 (three balls 301a to 301 in this embodiment) sandwiched between the fixed portion and the movable portion are rolling members.

First, the upper yoke 101, the lower yoke 108, and the base plate 110 that form the fixing portion will be described. The upper magnets 103a, 103b, 103c, 103d, 103e, and 103f are adhesively fixed to the upper yoke 101 in a state of being attracted to the upper yoke 101. The upper magnets 103a and 103b, 103c and 103d, 103e and 103f are adjacent to each other, respectively. The upper yoke 101 is fastened and fixed to the base plate 110 using screws 102a, 102b, 102c.

The lower magnets 107a, 107b, 107c, 107d, 107e, and 107f are adhesively fixed to the lower yoke 108 in a state of being attracted to the lower yoke 108. The lower magnets 107a and 107b, 107c and 107d, 107e and 107f are adjacent to each other, respectively.

The base plate 110 is provided with a plurality of holes so as to avoid the lower magnets 107a to 107a, and the surface of the magnet is configured to protrude from each hole. The base plate 110 and the lower yoke 108 are fastened and fixed by screws 109a, 109b, 109c. Since the lower magnets 107a to 107 have a larger dimension in the thickness direction than the base plate 110, they are in a state of protruding from the hole portion of the base plate 110.

The upper yoke 101 and the upper magnets 103a to 103, and the lower yoke 108 and the lower magnets 107a to 107 form a magnetic circuit, forming a so-called closed magnetic path. The upper magnets 103a to 103a and the lower magnets 107a to 107 are magnetized in the optical axis direction (vertical direction in FIG. 2), respectively, and adjacent magnets (for example, the upper magnets 103a and 103b) are magnetized in different directions. ing. Further, the upper magnet and the lower magnet (for example, the upper magnet 103a and the lower magnet 107a) facing each other are magnetized in the same direction. By doing so, a strong magnetic flux density is generated in the optical axis direction between the upper yoke 101 and the lower yoke 108.

Since a strong suction force is generated between the upper yoke 101 and the lower yoke 108, the main spacers 105a, 105b, 105c and the auxiliary spacers 104a, 104b are configured to maintain an appropriate distance on the base plate 110. The appropriate spacing here means that the coils 205a to 205 and the flexible printed circuit board (hereinafter referred to as FPC) 201, which will be described later, are arranged between the upper magnets 103a to 103a and the lower magnets 107a to f, and an appropriate gap is provided. It is an interval that can secure. The main spacers 105a, 105b, 105c are provided with screw holes. The upper yoke 101 is fixed to the main spacers 105a, 105b, 105c by the screws 102a, 102b, 102c. Rubber is installed on the body of each main spacer to form a mechanical end (so-called stopper) for the movable part.

The movable frame 206 and the FPC 201 form a movable portion. The movable frame 206 is arranged between the upper yoke 101 and the base plate 110. The movable frame 206 is formed of magnesium die-cast or aluminum die-cast, and is lightweight and highly rigid. The movable frame 206 is formed with recesses for accommodating the coils 205a, 205b, and 205c, respectively. The movable frame 206 includes a printed circuit board 203. The printed circuit board 203 is electrically connected to an image sensor 6, coils 205a, 205b, 205c (not shown) and a position detection element described later. The printed circuit board 203 sends and receives signals to and from an external circuit via a connector.

A position detection element such as a Hall element is mounted on the FPC 201, and its mounting positions 202a, 202b, and 202c are shown. The plurality of position detecting elements are mounted at mounting positions 202a, 202b, 202c on the opposite surface that cannot be seen in FIG.

The fixed portion rolling plates 106a, 106b, 106c are adhesively fixed to the base plate 110, and the movable portion rolling plates 204a, 204b, 204c are adhesively fixed to the movable frame 206. These rolling plates face each other and form rolling surfaces of the balls 301a, 301b, and 301c, respectively. That is, since the balls 301a to c are sandwiched between the fixed portion rolling plates 106a to c and the movable portion rolling plates 204a to c, respectively, the movable frame 206 is movably supported with respect to the base plate 110. To. Compared with the method of interposing the balls 301a to c between the base plate 110 and the movable frame 206 without using the fixed portion rolling plate and the moving portion rolling plate, the surface roughness is provided by providing the rolling plate separately. It becomes easy to design the pod hardness and the like in a preferable state.

By passing a current through the coils 205a to 205 in the image blur correction mechanism portion having the above-described configuration, a force according to Fleming's left-hand rule is generated, and the movable portion can be moved. In the present embodiment, the position of the movable portion is detected by using the magnetic detection element so that the position can be detected by using the magnetic circuit described above. For example, since the Hall element is a small element, it can be arranged so as to be nested inside the windings of the coils 205a to 205c. In addition, feedback control can be performed by using the signal of the Hall element. Based on the signal value of the Hall element, it is possible to control the translational motion of the movable portion and the rotational motion around the optical axis 4 in a plane orthogonal to the optical axis 4.

To briefly explain the control of rotating the image blur correction mechanism unit around the optical axis, the Hall element signals at the mounting positions 202b and 202c are in opposite phase while the Hall element signals at the mounting positions 202a are kept constant. Drive control is performed in this way. As a result, a rotational motion about the optical axis 4 can be generated.

It is the magnetic flux density in the optical axis direction that is detected at the mounting positions 202a, 202b, and 202c of the position detection element. The characteristics of a magnetic circuit including upper magnets 103a to 103f and lower magnets 107a to 107f are generally non-linear. Therefore, the magnetic flux densities detected at the mounting positions 202a, 202b, and 202c of the position detection element do not necessarily have a constant resolution in the entire drive range. That is, the detection resolution changes within the drive range. For example, the change in magnetic flux density has a steep position and a gentle position, and the steeper position has a higher detection resolution (the change in magnetic flux density with respect to the amount of movement is larger). In the magnetic circuit shown in FIG. 2, the change in magnetic flux density is the largest and the detection resolution is high at the boundary position of the magnet (for example, the boundary position between the upper magnets 103a and 103b). Since the details of the control method are well known, further description thereof will be omitted.

Leakage flux will be described with reference to FIG. FIG. 3 shows a state in which the image sensor 6 is attached to the blur correction unit 14, and FIG. 3A is a view when viewed from the optical axis direction. FIG. 3B is a cross-sectional view taken along the line AA of FIG. 3A. In FIG. 3, the reference numerals used in FIG. 2 will be used for description. The CMOS sensor 6a, the cover glass 6b, the sensor housing 6c, and the sensor holder 210 provided in the image sensor 6 are shown respectively. FIG. 3B schematically shows the leakage flux with arrows 31 and 32.

As shown in FIG. 3A, the image sensor 6 is fixed to the sensor holder 210 by a method such as adhesion, and then fixed to the movable frame 206. Therefore, when the movable frame 206 moves, the image sensor 6 also moves integrally. The magnetic flux is generated by the current flowing through the coil 205c (Coil 205c is illustrated in FIG. 3, but the same applies to other coils). Most of the magnetic flux is blocked by the upper yoke 101 and the lower yoke 108 made of a soft magnetic material. However, some magnetic flux reaches the CMOS sensor 6a by following the paths indicated by arrows 31 and 32. As a result, when the leakage flux acts on the CMOS sensor 6a, noise may be superimposed on the image signal, which is not preferable.

As will be described later, energization accompanying the control of the coil 205c is generally performed by a pulse width modulation (hereinafter referred to as PWM) method, and the direction and amount of the current fluctuate in a constant cycle. As a result, a so-called ripple current is generated, and an unnecessary magnetic flux is generated. Noise is generated by this unnecessary magnetic flux.

The PWM cycle is set to a value corresponding to a frequency sufficiently higher than the frequency at which a mechanical response is expected. For example, it is assumed that the image stabilization is controlled up to about 100 Hz. In this case, by setting the PWM frequency to 100 kHz or the like, fluctuations at the PWM frequency do not pose a problem in practical control, and only an average response is output. In the image blur correction mechanism unit described with reference to FIG. 2, high frequency components are sufficiently cut by the effect of the mass of the movable frame 206, so it may be understood that a mechanical LPF (low pass filter) is configured. Therefore, the fluctuation at the PWM frequency is not observed as the movement of the movable frame 206 (actually acting is the driving force).

The current waveform generated by PWM drive changes depending on the PWM frequency and coil impedance (resistance value and inductance). In general, the PWM frequency is sufficiently high, so that the current waveform of the coil is a current waveform having a frequency higher than the cutoff frequency determined by the impedance of the coil. In that case, a triangular wave is obtained as a response. The amplitude of the triangular wave is determined by the impedance of the coil. The current generated by this triangular wave is called the ripple current. The ripple current contains a large amount of PWM frequency components (since it is a triangular wave rather than a sine wave, harmonic components and the like are also included, but the PWM frequency component is also large). When a current flows through the coil, a magnetic flux corresponding to it is generated, and a magnetic flux is also generated by the ripple current. As a result, a magnetic flux that changes with the PWM frequency is generated.

When signals are sequentially read from the image sensor 6, the reading cycle is not completely synchronized with the PWM cycle for controlling the image blur correction mechanism unit. Therefore, since the change in magnetic flux caused by the ripple current acting for each read time is different, a level difference may occur in the image signal and noise may be generated.

In the following, the relationship between the ripple current, which is a magnetic noise source for the image sensor, and the PWM energization method in driving the motor will be described. FIG. 4A is a configuration diagram in the case of forward / reverse energization. Forward / reverse energization is a method that uses two potentials, + VM and -VM, with VM as the motor drive voltage. FIG. 4B is a configuration diagram in the case of on-short energization. On-short energization is a method that uses three potentials of + VM, 0, and -VM. 4 (A) and 4 (B) show the connection between the control unit 400 such as a control microcomputer, the motor driver IC, and the motor coil.

Examples of the motor driver IC include an H-bridge driver and the like. For example, in the motor driver IC, the terminals INA and INB in FIG. 4 are control input terminals A and B, and receive PWM input signals from the control unit 400. The OUTA and OUTB terminals are H-bridge output terminals A and B, and an output voltage corresponding to the waveform of the PWM signal input to the INA and INB terminals is applied to the motor coil.

The PS terminal is a power save terminal, and the signal to the PS terminal can be set to a high level to set the motor drive in the active mode, and set to a low level to set the standby mode. The PWM terminal is a drive mode switching terminal. The signal to the PWM terminal can be set to a high level, and the polarity of the output signals of the OUTA and OUTB terminals, that is, the forward and reverse rotation of the motor can be defined only by the signal of the INB terminal. Further, the forward rotation and the inversion can be specified by setting the signal to the PWM terminal to a low level and switching both the signal of the INA terminal and the signal of the INB terminal.

The VM terminal is a motor power supply terminal, and the GND terminal is a ground terminal. The H-bridge driver is equipped with an H-bridge circuit (not shown). The H-bridge circuit is an amplifier that amplifies and outputs the PWM signal voltage from the control unit 400 to the VM. The H-bridge circuit has four switch elements, and switches the two terminals of the motor to forward rotation at a positive voltage, inverting at a negative voltage, stopping at a short circuit, and switching to standby at a release. Since the H-bridge circuit itself is known, a detailed description thereof will be omitted.

In the case of forward / reverse energization shown in FIG. 4A, the PWM input signal from the control unit 400 to the motor driver IC is one signal (INB signal) to only the INB terminal. Further, in the case of on-short energization shown in FIG. 4B, the PWM input signals from the control unit 400 to the motor driver IC are two signals (INA signal and INB signal) to the INA terminal and the INB terminal. That is, in the control using only the INB signal, the output has two potentials of + VM and −VM. In the control by switching between the INA signal and the INB signal, the output has three potentials of + VM, 0, and −VM.

The input signal waveform and the output voltage / current waveform in each method will be described with reference to FIGS. 5 and 6. FIG. 5 shows the case of forward / reverse energization, and FIG. 6 shows the case of on-short energization. In each figure, the negative voltage applied state is shown in (A), the zero voltage applied state is shown in (B), and the positive voltage applied state is shown in (C). Moreover, the time change of the input voltage, the output voltage (Vcoil), and the current (Icoil) is shown in order from the top.

In the case of forward / reverse energization shown in FIG. 5, the polarities of OUTA and OUTB are controlled only by the INB signal. When the output voltage is set to zero, if the duty ratio of the INB signal is fixed at High 50% / Low 50%, + VM and -VM are output at a ratio of 50% each, so the output voltage is 0V on average. (See FIG. 5 (B)). Further, when the duty ratio during the high level period is made larger than 50%, the output voltage becomes a positive voltage. For example, if the duty ratio is High 75% / Low 25%, + VM is output at a ratio of 75% and -VM is output at a ratio of 25%, so that the output voltage is +0.5 VM on average (see FIG. 5C). .. On the other hand, if the duty ratio is High 25% / Low 75%, + VM is output at a ratio of 25% and -VM is output at a ratio of 75%, so that the output voltage is -0.5 VM on average (see FIG. 5 (A)). ).

In the case of on-short energization shown in FIG. 6, the polarities of OUTA and OUTB are controlled by switching between the INA signal and the INB signal. When the output voltage is set to zero, if both INA and INB are fixed in the High state, there is no potential difference between OUTA and OUTB, so the output voltage becomes 0V (see FIG. 6B). When the output voltage is a positive voltage, the INB signal may be fixed in the High state and the INA signal may be controlled in Low / High. For example, if the duty ratio of the INA signal is fixed at Low 50% / High 50%, + VM is output at a ratio of 50% and 0V is output at a ratio of 50%, so that the output voltage becomes +0.5 VM on average (see FIG. 6C). ). When the output voltage is a negative voltage, the INA signal may be fixed in the High state and the INB signal may be controlled in Low / High. For example, if the duty ratio of the INB signal is fixed at Low 50% / High 50%, -VM is output at a ratio of 50% and 0V is output at a ratio of 50%, so that the output voltage becomes -0.5VM on average (FIG. 6 (A). )reference).

Comparing the current behavior between the forward / reverse energization (FIG. 5) and the on-short energization (FIG. 6), it can be seen that the fluctuation width (ripple) of the current is large in the forward / reverse energization and small in the on-short energization. When the impedance (resistance, inductance) of the coil is constant, the current correlates with the voltage. Even if the apparent output voltage is the same, the forward and reverse energization has twice the voltage fluctuation as the on-short energization, so the current ripple is large. In particular, when 0 V is applied, no ripple current is generated during on-short energization (see FIG. 6B), and the difference from forward and reverse energization becomes remarkable.

On-short energization is preferable from the viewpoint of reducing magnetic noise. However, in the case of on-short energization, the number of input signals is twice that in the case of forward / reverse energization. Therefore, depending on the number of motor coils to be controlled, wiring may become complicated and the number of control ports in the control microcomputer may increase.

Therefore, in the present embodiment, the above problem is solved by analyzing one input signal according to regularity and providing an input signal analysis unit that separates the two signals. Specific examples will be described with reference to FIGS. 7 to 10.

FIG. 7 is a block diagram showing the configuration of the PWM signal output device 408 of the present embodiment. The PWM signal output device 408 is a device that outputs a PWM signal designated by the control unit 400 by a predetermined method. The PWM signal output device 408 includes an input signal analysis unit 402, a signal input unit 403, a signal amplification unit 404, a signal output unit 405, a drive voltage input unit 406, and a PWM cycle determination unit 409.

The input signal analysis unit 402 analyzes the signal from the control unit 400, and the signal input unit 403 detects two values of the High (high) level and the Low (low) level. The input signal analysis unit 402 performs a process of switching commands to the signal amplification unit 404 based on the analysis result of the input signal. The drive voltage is supplied from the drive voltage input unit 406 to the signal amplification unit 404, and the drive voltage is applied from the signal amplification unit 404 to the motor 407 via the signal output unit 405.

The signal output unit 405 has two output units. The states corresponding to the logical combination of the potentials of these output units are the following five states.
(1) High and Low.
(2) Low and High.
(3) High and High.
(4) Low and Low.
(5) High impedance (z) and high impedance (z).
For example, High corresponds to a predetermined voltage value and Low corresponds to the GND level. From the above five states, control is performed in three predetermined states.

First, one system of PWM input signals is input to the input signal analysis unit 402 from the control unit 400. The input signal analysis unit 402 analyzes the input signal according to regularity, separates it into two signals, and transmits the input signal to the signal input unit 403. Specifically, the signal input unit 403 corresponds to the INA terminal and the INB terminal shown in FIG. The drive voltage input unit 406 corresponds to the VM terminal shown in FIG. 4, and the signal amplification unit 404 corresponds to an H-bridge circuit (not shown). The signal output unit 405 corresponds to the OUTA terminal and the OUTB terminal. The signal output unit 405 is connected to the coil of the motor 407 and applies an output voltage. The signal input unit 403, the signal amplification unit 404, the signal output unit 405, and the drive voltage input unit 406 are components of the motor driver IC (H-bridge driver) described above, and these may be integrally treated as the motor driver 401. ..

Explaining the relationship between the configuration shown in FIG. 1B and each configuration unit in FIG. 7, the control unit 400 corresponds to the camera control unit 5, and the motor 407 corresponds to the actuator of the blur correction unit 14. The PWM signal output device 408 is interposed between the camera control unit 5 and the actuator of the blur correction unit 14, analyzes one PWM input signal from the camera control unit 5, and amplifies the signal to turn on the blur correction unit 14. Control by short-circuit energization.

The PWM signal output device 408 has a configuration in which the input signal analysis unit 402 and the motor driver 401 are combined, but is not limited to such a configuration. The input signal analysis unit 402 may be incorporated into the motor driver 401 and integrated as a package.

The PWM signal output device 408 determines the logical combination of the potentials of the two output units of the signal output unit 405 based on the definition of the input / output logic of the signal amplification unit 404. For example, when the output voltage is set to zero, the logical combination of potentials of each output unit is High / High, Low / Low, or high impedance (z) / high impedance (z). z / z is a so-called open circuit state, and has different controllability in a device that consumes residual power. When the output voltage is a positive voltage, the logical combination of the potentials of each output unit is High / Low. When the output voltage is set to a negative voltage, the logical combination of the potentials of each output unit is Low / High. However, depending on the definition of the input / output logic of the signal amplification unit 404, the logical combination when the positive voltage is set may be Low / High, and the logical combination when the negative voltage is set may be High / Low.

In the PWM signal output device 408, three logical combinations are selected from the above five logical combinations. For example, the combination is free, such as selecting three of High / Low, Low / Low, and z / z. Generally, three logical combinations of High / Low, Low / High, and Low / Low (or z / z) are selected.

An example of a specific analysis method of the input signal analysis unit 402 will be described with reference to FIG. FIG. 8 is a diagram illustrating an example of three logical combinations relating to the potentials of two output units in the signal output unit 405.

FIG. 8A shows one PWM input signal from the control unit 400, the horizontal axis represents the time axis, and the vertical axis represents the input voltage. In the figure, TF represents the PWM cycle time, and TH represents the High section where the input voltage is the High level. The ratio of the length (time) of the section TH to the PWM cycle time TF corresponds to the duty ratio of the high section. Further, TL represents a Low section in which the input voltage is at the Low level, and the ratio of the length (time) of the section TL to the PWM cycle time TF corresponds to the duty ratio of the Low section.

The input signal analysis unit 402 can perform edge detection at the timing when the input signal is switched from Low to High and at the timing when the input signal is switched from High to Low. The input signal analysis unit 402 calculates the time from the timing of switching from the first Low to High to the timing of switching from the second Low to High, and sets it as TF. Alternatively, the input signal analysis unit 402 calculates the time from the timing of switching from the first High to Low to the timing of switching from the second High to Low, and sets it as TF.

Further, the input signal analysis unit 402 sets TH and TL at the same time as the calculation of TF. The input signal analysis unit 402 calculates the time from the first timing of switching from Low to High for the first time to the second timing of switching from High to Low, and sets it as TH. The input signal analysis unit 402 calculates the time from this second timing to the third timing of switching from Low to High for the second time, and sets it as TL.

Subsequently, the input signal analysis unit 402 subtracts TL from TH and calculates the difference between TH and TL (denoted as Δ. Δ = TH-TL). The input signal analysis unit 402 determines from the following (i) to (iii) according to the Δ value.
(I) When Δ = 0 The process of fixing the INA to High and fixing the INB to High is performed. This corresponds to the case where the output voltage in the on-short energization is 0 V, and the combination of the potentials of the two output units of the signal output unit 405 is Low / Low.

(Ii) When Δ> 0 A process is performed in which INB is fixed to High and INA is set to Low / High control. The Low section length of INA is set to Δ, and the High section length is set to “TF−Δ”. This corresponds to the case where the output voltage in the on-short energization is a positive voltage. Regarding the combination of the potentials of the two output units of the signal output unit 405, it is High / Low in the Low section of INA and Low / Low in the High section of INA.

(Iii) When Δ <0, the process of fixing the INA to High and controlling the INB to Low / High is performed. The Low section length of INB is set to "-Δ", and the High section length is set to "TF + Δ". This corresponds to the case where the output voltage in the on-short energization is a negative voltage. Regarding the combination of the potentials of the two output units of the signal output unit 405, it is Low / High in the Low section of INB and Low / Low in the High section of INB.
The Low / Low in (i) to (iii) may be High / High or z / z.

The input signal analysis unit 402 separates the input signal into two signals according to the above regularity and transmits the input signal to the signal input unit 403 (INA, INB). The output voltage is determined based on the two signals acquired by the signal input unit 403.

The analysis of the input signal is continuously performed every one cycle of the PWM signal. That is, the control performed by the input signal analysis unit 402 on the signal amplification unit 404 is performed every period during which the PWM cycle time related to the input signal continues. As a method of changing the drive pattern by analyzing the input signal, a driver for motor control using command transmission by serial communication is known. In this case, if it takes time to transmit the command, the motor output control becomes discontinuous. In the present embodiment, since the analysis of the input signal is given regularity, the input signal can be continuously analyzed for each PWM cycle. Therefore, it is possible to respond accurately and flexibly to fluctuations in the input signal. The two signals separated by the signal analysis are transmitted to the signal input unit 403 with a delay of one pulse of the input signal, but the delay time is almost negligible in terms of motor controllability. ..

FIG. 8B is a timing chart showing a control example in which the Δ value of the input signal is gradually reduced from the positive side to shift to zero, and corresponds to the above-mentioned operation from (ii) to (i). The time change of the input voltage is shown on the upper side, and the time change of the output voltage is shown on the lower side. When the duty ratio of the high section of the input signal is 75% and the duty ratio of the low section is 25%, the output voltage is increased by the process of setting + VM to 50% and 0V to 50% from the signal analysis results. The average is +0.5 VM. When the duty ratio of the high section of the input signal is 70% and the duty ratio of the low section is 30%, the output voltage is +0.4VM on average by the process of setting + VM to 40% and 0V to 60%. It becomes. When the duty ratio of the high section of the input signal is 50% and the duty ratio of the low section is 50%, the output voltage becomes 0V by the process of setting + VM to 0% and 0V to 100%.

FIG. 8C is a timing chart showing a control example in which the magnitude of the Δ value of the input signal is gradually increased from zero to the negative side, and corresponds to the above-mentioned operation from (i) to (iii). The time change of the input voltage is shown on the upper side, and the time change of the output voltage is shown on the lower side. When the duty ratio of the high section of the input signal is 50% and the duty ratio of the low section is 50%, the output voltage is increased by the process of setting + VM to 0% and 0V to 100% from the signal analysis results. It becomes 0V. When the duty ratio of the high section of the input signal is 30% and the duty ratio of the low section is 70%, the output voltage is -0 on average by the process of setting -VM to 40% and 0V to 60%. It becomes 0.4VM. When the duty ratio of the high section of the input signal is 25% and the duty ratio of the low section is 75%, the output voltage is -0 on average by the process of setting -VM to 50% and 0V to 50%. It becomes .5VM.

Next, the process and control for determining the PWM cycle of the output signal will be described. The PWM signal output device 408 further includes a PWM cycle determination unit 409 that determines the PWM cycle of the output signal. The PWM cycle determination unit 409 can arbitrarily apply scaling (enlargement / reduction) to the TF, TH, and TL calculated by the input signal analysis unit 402 at the same ratio.

FIG. 9 is a timing chart when the PWM cycle time of the output voltage is scaled to, for example, 1/10 with respect to the input signal. The time change of the input voltage is shown on the upper side, and the time change of the output voltage is shown on the lower side. The input signal analysis unit 402 transmits to the signal input unit 403 with the PWM cycle of the output signal as 1/10 of the analysis for one pulse of the input signal. As a result, the signal output unit 405 outputs a pulse having a PWM cycle of 1/10. The input signal analysis unit 402 analyzes one pulse of the next input signal, and during that time, 10 pulses with the same waveform are output as pulses having a PWM cycle of 1/10. In this way, it is possible to control the ratio of the number of pulses between the input signal and the output voltage.

Further, the PWM signal output device 408 controls by providing a dead zone near zero of the Δ value in the input signal. For example, even if the duty ratio of the high section of the input signal is set to 50% and the duty ratio of the low section is set to 50% (that is, Δ = 0), the Δ value is slightly from zero due to the error and noise of the input signal. There is a possibility of deviation. In this case, even though a stop command corresponding to the output voltage of 0 V is issued as an input signal, the output voltage may be applied to the motor coil due to an error or noise, and a slight operation of the motor may occur. Therefore, in order to suppress an operation caused by an error or noise, "Δ = 0" is uniformly set as a dead zone when the absolute value of Δ is from 0 to a predetermined value N.

FIG. 10 is a timing chart showing an example in which a dead zone is provided near zero of the Δ value in the input signal. The time change of the input voltage is shown on the upper side, and the time change of the output voltage is shown on the lower side. In this case, the PWM signal output device 408 sets the dead zone in a range in which the absolute value of the difference between the duty ratio in the high section and the duty ratio in the low section is less than a predetermined threshold value (for example, 6%). That is, the output voltage of 0 V or more is output from the time when the absolute value of the difference becomes 6% or more. The value of the dead zone can be set to any value. For example, when the absolute value of the difference between the duty ratio in the high section and the duty ratio in the low section is larger than 10%, malfunctions and the like can be sufficiently prevented, so that the threshold value can be arbitrarily set from a value of 10% or less. You may set it so that it can be selected.

The PWM signal output device 408 treats the input signal from the control unit 400 to the motor driver 401 as one signal as in the case of forward / reverse energization, and the output voltage from the motor driver 401 to the motor 407 is + VM as in the on-short energization. , 0, -VM 3 potentials are used. Therefore, it is possible to obtain the effect of suppressing the complicated wiring and the increase in the number of control ports in the control unit, which have been problems in on-short energization.

The PWM signal output device 408 can be applied to, for example, a blur correction unit 14 having an image plane vibration isolation mechanism in an image pickup device. The PWM signal output device 408 is interposed between the camera control unit 5 and the actuator of the blur correction unit 14. Since one PWM signal output by the camera control unit 5 can be analyzed and the actuator of the blur correction unit 14 can be controlled by on-short energization, it has the effect of suppressing magnetic noise due to the ripple current. Further, the effect of suppressing an increase in the number of control ports required by the camera control unit 5 can be obtained.

In the above embodiment, an example of application to the blur correction unit 14 that drives the image sensor has been shown, but the PWM signal output device 408 includes a drive unit (lens drive unit 13) of an optical member such as a lens and various PWM-controlled devices. It can be widely applied to actuators.

5. Camera system control unit 14. Blur correction unit 400. Control unit 401. Motor driver 402. Input signal analysis unit 403. Signal input unit 404. Signal amplification unit 405. Signal output unit 406. Drive voltage input unit 407. Motor 408. PWM signal output device

Claims (12)

A signal output device that outputs by pulse width modulation according to the input signal.
An analysis means for analyzing the input signal and
A signal input means for acquiring a plurality of signals from the analysis means, and
Amplifying means for amplifying the signal from the signal input means and
It has a plurality of output units, and includes an output means connected to the amplification means.
When switching the command to the amplification means according to the analysis result of the input signal, the analysis means is determined from the state of a plurality of signals and the state of high impedance corresponding to the logical combination of potentials related to the plurality of output units. A signal output device characterized in that control is performed in a state, and the output means outputs an output corresponding to each of the three states from the plurality of output units. The analysis means controls in three predetermined states out of four states corresponding to the combination of the high level signal and the low level signal and five states including the high impedance and high impedance states. Do,
The signal output device according to claim 1, wherein the signal input means acquires two signals separated by the analysis means and performs high-level and low-level detection. The analysis means detects a first timing at which the input signal switches from low level to high level and a second timing at which the input signal switches from high level to low level, and from the first timing to the next The time to the timing of 1 or the time from the second timing to the next second timing is calculated to determine the cycle time of pulse width modulation, and the input signal is at a high level at the cycle time. The signal output device according to claim 2, wherein the first time and the second time when the input signal is at a low level are detected. When the time obtained by subtracting the second time from the first time is expressed as Δ,
The analysis means
When the value of Δ is larger than zero, the logical combination of the potentials related to the plurality of output units is set as the first logical combination in the first section corresponding to the value of Δ in the period of the cycle time, and the second logical combination. In the section of, control is performed as the third logical combination,
When the value of Δ is smaller than zero, the logic of the potentials related to the plurality of output units in the third section corresponding to the time obtained by subtracting the first time from the second time in the period of the cycle time. The signal output device according to claim 3, wherein the combination is a second logical combination, and control is performed so that the combination is the third logical combination in the fourth section. The output means
In the first logical combination, a potential difference in the first direction is generated between the plurality of output units.
In the second logical combination, a potential difference in a second direction opposite to the first direction is generated between the plurality of output units.
The signal output device according to claim 4, wherein a potential difference is not generated between the plurality of output units in the third logical combination. The signal according to any one of claims 3 to 5, wherein the control performed by the analysis means on the amplification means is performed every period during which the cycle time of the input signal continues. Output device. Further provided with a determination means for determining the period of pulse width modulation related to the output signal of the signal output device.
The determination means according to any one of claims 1 to 6, wherein the determination means changes the pulse width modulation cycle related to the output signal with respect to the pulse width modulation cycle related to the input signal. Signal output device. The signal output device according to claim 5, wherein the analysis means controls by the third logical combination with a range in which the absolute value of Δ is smaller than a threshold value as a dead zone. The signal output device according to any one of claims 1 to 8, further comprising a voltage input means for inputting a driving voltage to an actuator connected to the signal output device. The signal output device according to any one of claims 1 to 9.
An actuator that operates according to the output of the signal output device and
An image pickup apparatus including an optical member or an image pickup element driven by the actuator. A correction means that drives the image sensor by the actuator to correct image blurring,
The imaging device according to claim 10, further comprising a control means for controlling the correction means. It is a control method executed by a signal output device that outputs by pulse width modulation according to an input signal.
The signal output device is
An analysis means for analyzing the input signal and
A signal input means for acquiring a plurality of signals from the analysis means, and
Amplifying means for amplifying the signal from the signal input means and
It has a plurality of output units, and includes an output means connected to the amplification means.
The control method is
When switching the command to the amplification means according to the analysis result of the input signal performed by the analysis means, three states are selected from the state of a plurality of signals corresponding to the logical combination of potentials related to the plurality of output units and the state of high impedance. The process of deciding and
A control method for a signal output device, comprising: that the output means outputs an output corresponding to each of the three states from the plurality of output units according to the determined control in the three states.

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