WO2014065036A1

WO2014065036A1 - Voice coil motor (vcm) drive device and portable terminal

Info

Publication number: WO2014065036A1
Application number: PCT/JP2013/074707
Authority: WO
Inventors: 俊治中馬
Original assignee: 富士フイルム株式会社
Priority date: 2012-10-26
Filing date: 2013-09-12
Publication date: 2014-05-01

Abstract

Provided is a VCM drive device that reduces power loss so as to enable low power consumption even in a case where a VCM is driven by either linear drive or PWM drive. A VCM drive unit (20) is provided with the following: a direct current power supply (40); N channel type bipolar transistors (21, 22) and N channel type MOSFETs (23, 24) that form an H bridge circuit; and a control unit (26) that controls the transistors and thereby controls the current that is supplied to a coil (90) that forms a VMC (9).

Description

Voice coil motor (VCM) drive device and portable terminal

The present invention relates to a voice coil motor (VCM) driving device and a portable terminal including the same.

VCM has the advantages of small volume, low power consumption, low price, etc., short distance actuators in electronic products, such as mobile phone vibration motor, magnetic head / optical pickup vertical movement actuator, camera autofocus It is used for actuators and the like.

As a VCM drive circuit, an H-bridge circuit that is a circuit that can change the direction of a voltage applied to a motor with a single power source is well known. The H-bridge circuit includes two first switching elements connected in parallel to the power supply and a second switching element connected in series to each of the two first switching elements.

Then, a P-channel MOSFET (field effect transistor) is used as the first switching element, an N-channel MOSFET is used as the second switching element, and a P-channel bipolar transistor is used as the first switching element. A device using an N-channel bipolar transistor as a second switching element is known.

Further, in Patent Document 1, as an H-bridge circuit for driving a stepping motor, two P-channel MOSFETs connected in parallel to a power source and each of the two P-channel MOSFETs are connected in series. What is provided is a bipolar transistor having a Darlington connection configuration.

Although not an H-bridge circuit, Patent Document 2 describes a three-phase inverter device in which a switching element constituting the upper arm side switching circuit is a MOSFET and a switching element constituting the lower arm side switching circuit is a bipolar transistor. Has been.

Japanese Patent Laid-Open No. 5-236797 Japanese Unexamined Patent Publication No. 2011-20564

In the H-bridge circuit using the P-channel MOSFET as the first switching element, when the P-channel MOSFET is linearly driven, the driving voltage of the H-bridge circuit depends on the on-resistance of the P-channel MOSFET and the P-channel MOSFET. Depends on gate-source voltage. Since the gate-source voltage of the P-channel MOSFET is large, the drive voltage of the H-bridge circuit cannot be sufficiently lowered even if the power consumption is reduced by using a VCM having a low drive voltage.

In an H-bridge circuit using a P-channel bipolar transistor as the first switching element and an N-channel bipolar transistor as the second switching element, the base current of the transistor flows to the ground without being supplied to the VCM. Current is wasted. In particular, when the P-channel bipolar transistor is maintained in a saturated state and the N-channel bipolar transistor is driven by PWM (pulse width modulation), more current flows to the ground and is wasted.

In portable terminals that operate on batteries such as digital cameras and mobile phones, reduction of power consumption is a major issue, so it is required to reduce the driving voltage of a circuit that drives a VCM. However, the VCM drive circuit proposed so far has a limit in reducing power consumption regardless of whether linear drive or PWM drive is performed.

The present invention has been made in view of the above circumstances, and provides a VCM drive device capable of reducing power loss and reducing power consumption when driving a VCM by either linear drive or PWM drive. For the purpose.

The VCM driving device of the present invention is a VCM driving device for driving a voice coil motor, and is connected in series to the first transistor and the second transistor connected in parallel to the DC power source and the first transistor. A third transistor connected in series to the second transistor, and the first transistor, the second transistor, the third transistor, and the fourth transistor are controlled. And a controller for controlling the current flowing through the coil constituting the voice coil motor, and one end of the coil is connected between the first transistor and the third transistor, An end is connected between the second transistor and the fourth transistor, and the first transistor and the second transistor are connected. Data is a bipolar transistor of the N-channel type, respectively, said third transistor and said fourth transistor is a field effect transistor of each N-channel type.

According to the present invention, it is possible to provide a VCM driving device capable of reducing power loss and reducing power consumption when the VCM is driven by either linear driving or PWM driving.

The figure which shows schematic structure of the digital camera for describing one Embodiment of this invention 1 is a circuit diagram showing an internal configuration of a VCM drive unit 20 in the digital camera shown in FIG. The figure which shows an example of the drive timing chart of the VCM drive part 20 at the time of imaging mode of the digital camera shown in FIG. The figure which shows another example of the drive timing chart of the VCM drive part 20 at the time of imaging mode of the digital camera shown in FIG. The figure which shows another example of the drive timing chart of the VCM drive part 20 at the time of imaging mode of the digital camera shown in FIG. The figure explaining a smart phone as an imaging device Internal block diagram of the smartphone of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an imaging apparatus for explaining an embodiment of the present invention. Examples of the imaging device include an imaging device such as a digital camera and a digital video camera, an imaging module mounted on an electronic endoscope, a camera-equipped mobile phone, and the like. Here, a digital camera will be described as an example.

The imaging system of the illustrated digital camera includes a photographing lens 1 including a focus lens, a solid-state imaging device 4 such as a CCD image sensor or a CMOS image sensor, and a diaphragm 2 provided therebetween. The position of the focus lens is controlled by a voice coil motor (VCM) 9.

The system control unit 11 that performs overall control of the entire electric control system of the digital camera drives the VCM 9 via the VCM drive unit 20 and adjusts the focus position. Further, the system control unit 11 controls the opening amount of the diaphragm 2 via the diaphragm driving unit 8 to adjust the exposure amount. In addition, the system control unit 11 drives the solid-state imaging device 4 via the imaging device driving unit 7 and outputs a subject image captured through the photographing lens 1 as a captured image signal. An instruction signal from the user is input to the system control unit 11 through the operation unit 12.

The electric control system of the digital camera further includes an analog signal processing unit 5 that performs analog signal processing such as correlated double sampling processing connected to the output of the solid-state imaging device 4, and a signal output from the analog signal processing unit 5. And an A / D conversion circuit 6 for converting the signal into a digital signal. The analog signal processing unit 5 and the A / D conversion circuit 6 are controlled by the system control unit 11.

Furthermore, the electric control system of the digital camera performs various image processing on the main memory 14, the memory control unit 13 connected to the main memory 14, and the captured image signal output from the A / D conversion circuit 6 to capture the image. A digital signal processing unit 15 that generates image data, a compression / decompression processing unit 16 that compresses the captured image data generated by the digital signal processing unit 15 into a JPEG format or expands the compressed image data, and a detachable recording An external memory control unit 17 to which the medium 18 is connected, and a display control unit 19 to which the liquid crystal display unit 10 mounted on the rear surface of the camera or the like is connected. The memory control unit 13, the digital signal processing unit 15, the compression / decompression processing unit 16, the external memory control unit 17, and the display control unit 19 are connected to each other by a control bus 24 and a data bus 25, and commands from the system control unit 11. Controlled by.

The battery 30 is detachable from the digital camera, and the digital camera is provided with a power supply circuit 40 that generates a DC voltage necessary for each part in the camera from the power of the battery 30. The voltage generated by the power supply circuit 40 is supplied to each unit via the system control unit 11.

FIG. 2 is a circuit diagram showing an internal configuration of the VCM driving unit 20 in the digital camera shown in FIG.

The VCM drive unit 20 includes an N-channel bipolar transistor 21 and an N-channel MOSFET 24 for flowing current in one direction with respect to the coil 90 constituting the VCM 9, and a reverse direction of the one direction with respect to the coil 90. An N-channel bipolar transistor 22 and an N-channel MOSFET 23 for flowing current, a current detection resistor 25, and a control unit 26 are provided.

The collector terminal of the bipolar transistor 21 and the collector terminal of the bipolar transistor 22 are connected to the power supply circuit 40, respectively.

The MOSFET 23 has a source terminal connected to the emitter terminal of the bipolar transistor 21 and a drain terminal connected to the current detection resistor 25.

The MOSFET 24 has a source terminal connected to the emitter terminal of the bipolar transistor 22 and a drain terminal connected to the current detection resistor 25.

One end of a coil 90 is connected between the emitter terminal of the bipolar transistor 21 and the source terminal of the MOSFET 23, and the other end of the coil 90 is connected between the emitter terminal of the bipolar transistor 22 and the source terminal of the MOSFET 24. .

Thus, the

bipolar transistors

21 and 22, the

MOSFETs

23 and 24, and the coil 90 constitute a so-called H-bridge circuit.

The control unit 26 is connected to the base terminals of the

bipolar transistors

21 and 22 and the gate terminals of the

MOSFETs

23 and 24. The control unit 26 is also connected between the current detection resistor 25 and the MOSFET 23.

The current detection resistor 25 is provided to detect the current flowing through the path of the bipolar transistor 22, the coil 90, and the MOSFET 23 and the current flowing through the path of the bipolar transistor 21, the coil 90, and the MOSFET 24.

The control unit 26 controls the base voltage of the

bipolar transistors

21 and 22 and the gate voltages of the

MOSFETs

23 and 24 in accordance with a command from the system control unit 11 to control the current flowing through the coil 90. The control unit 26 acquires a current value detected using the current detection resistor 25, and controls the voltage based on the current value so that the current flowing through the coil 90 is stabilized at the command value from the system control unit 11. To do.

The control unit 26 selectively performs either PWM control for intermittently controlling the current flowing through the coil 90 or linear control for continuously controlling the current flowing through the coil 90, or these. There are two patterns for PWM control and linear control.

(First pattern of PWM control)
The control unit 26 causes the MOSFET 24 or the MOSFET 23 to function as a voltage control type switch, and the PWM control is performed by intermittently applying a voltage to the base terminal of the bipolar transistor 21 or the bipolar transistor 22 with this switch turned on. I do. Since the

bipolar transistors

21 and 22 are N-channel type, the base current at the time of PWM control can be used as the driving current for the coil 90, and the base current is not wasted and the driving voltage can be reduced.

(Second pattern of PWM control)
The control unit 26 causes the MOSFET 24 or the MOSFET 23 to function as a voltage control type switch in a state where the output of the bipolar transistor 21 or the bipolar transistor 22 is saturated, and switches the switch by applying a voltage intermittently to the gate terminal of the MOSFET 24 or the MOSFET 23. PWM control is performed by switching on and off.

In this case, the collector-emitter saturation voltage of the

bipolar transistors

21 and 22 is 0.1 V, the voltage drop at the coil 90 is 1 V, the voltage drop when the

MOSFETs

23 and 24 are on is 0.1 V, and the current detection resistor Assuming that the voltage drop at 0.2 V is 0.2 V, the voltage of the power supply connected to the collectors of the

bipolar transistors

21 and 22 may be 1.4 V, and the voltage can be reduced. Moreover, since the

bipolar transistors

21 and 22 have a base-emitter voltage as low as about 0.65 V, the base voltage can be lowered and the voltage can be reduced.

(First linear control pattern)
The control unit 26 functions as the voltage control type switch with the MOSFET 24 or the MOSFET 23 in a state in which the bipolar transistor 21 or the bipolar transistor 22 functions as a linear regulator and the base voltage is controlled so that the current flowing through the coil 90 becomes the command value. Then, linear control is performed by turning on this switch. At this time, power loss in the

MOSFETs

23 and 24 can be reduced by applying a gate-source voltage so that the on-resistances of the

MOSFETs

23 and 24 are as low as possible. In addition, since the

bipolar transistors

21 and 22 have a base-emitter voltage as low as about 0.65 V, the base voltage can be lowered and the voltage can be lowered even when linear control is performed.

(Second pattern of linear control)
The control unit 26 causes the bipolar transistor 21 or the bipolar transistor 22 to function as a current control type switch, and with this switch turned on, causes the MOSFET 24 or the MOSFET 23 to function as a linear regulator so that the current flowing through the coil 90 is a command value. Linear control is performed by controlling the gate voltage so that Even in this control, since the base-emitter voltage of the

bipolar transistors

21 and 22 is as low as about 0.65 V, the base voltage can be lowered and the voltage can be lowered. Further, since the base currents of the

bipolar transistors

21 and 22 can be used as the drive current for the coil 90, the base voltage can be lowered.

During the imaging mode, the control unit 26 selects and executes either the first pattern PWM control or the first pattern linear control. Alternatively, the control unit 26 selects and executes either PWM control of the first pattern or linear control of the second pattern. Alternatively, the control unit 26 selects and executes either the second pattern PWM control or the first pattern linear control.

PWM control has the advantage of high power supply efficiency, and linear control has the advantage of less influence of switching noise. Therefore, in the digital camera of FIG. 1, PWM control is performed at the time of imaging by the solid-state imaging device 4 for live view image display to save energy, and the solid-state imaging device 4 for recording captured image data on the recording medium 18 is used. At the time of imaging, linear control is performed to improve image quality.

FIG. 3 is a diagram illustrating an example of a drive timing chart of the VCM drive unit 20 in the imaging mode of the digital camera shown in FIG.

When the imaging mode is set, periodic imaging is started by the solid-state imaging device 4, and a live view image based on captured image data obtained by each imaging is displayed on the display unit 10 every time imaging is completed. During imaging for obtaining the live view image, the control unit 26 performs PWM control of the second pattern as shown in FIG. When a shooting instruction is given while the live view image is displayed, the system control unit 11 causes the solid-state imaging device 4 to perform imaging for recording. During this imaging, the control unit 26 performs linear control of the first pattern as shown in FIG.

According to the driving example shown in FIG. 3, since the saturation voltage between the collector and emitter of the

bipolar transistors

21 and 22 is low, power loss in the bipolar transistor can be reduced during PWM control. Also, during PWM control, the base current of the bipolar transistor can be used as the drive current for the VCM 9.

FIG. 4 is a diagram showing another example of a drive timing chart of the VCM drive unit 20 in the imaging mode of the digital camera shown in FIG.

During imaging for obtaining a live view image, the control unit 26 performs PWM control of the first pattern as shown in FIG. When a shooting instruction is given while the live view image is displayed, the system control unit 11 causes the solid-state imaging device 4 to perform imaging for recording. During this imaging, the control unit 26 performs linear control of the first pattern as shown in FIG.

According to the drive example shown in FIG. 4, PWM control is performed by intermittently controlling the base voltages of the

bipolar transistors

21 and 22. Therefore, compared with the drive example shown in FIG. 3, the influence of switching noise during PWM control is reduced. can do. In addition, during PWM control, the base current of the bipolar transistor can be used as the drive current for the VCM 9.

FIG. 5 is a diagram showing still another example of the drive timing chart of the VCM drive unit 20 in the imaging mode of the digital camera shown in FIG.

During imaging to obtain a live view image, the control unit 26 performs PWM control of the first pattern as shown in FIG. When a shooting instruction is given while the live view image is displayed, the system control unit 11 causes the solid-state imaging device 4 to perform imaging for recording. During this imaging, the control unit 26 performs the second pattern linear control as shown in FIG.

According to the driving example shown in FIG. 5, the same effect as in FIG. 4 can be obtained during PWM control. Further, during linear control, the base currents of the

bipolar transistors

21 and 22 can be used as the drive current of the VCM 9, so that the gate voltages of the

MOSFETs

23 and 24 can be suppressed. In addition, since the collector-emitter saturation voltage of the

bipolar transistors

21 and 22 is low, power loss in the bipolar transistor can be reduced during linear control.

As described above, according to the VCM driving unit 20 of the present embodiment, two transistors on the input power source side among the transistors configuring the H bridge circuit are N-channel bipolar transistors, and the remaining transistors are N-channel transistors. Therefore, the drive voltage of the VCM 9 can be lowered when performing either PWM control or linear control. For this reason, the battery life of the digital camera can be lengthened.

Further, according to the VCM drive unit 20, as shown in FIGS. 3, 4 and 5, switching between PWM control and linear control can be easily performed, and a camera that achieves both energy saving and high image quality can be realized. it can.

Note that, here, an imaging apparatus such as a digital camera is taken as an example, but the VCM driving unit 20 of the present embodiment can be applied to any electronic device equipped with the VCM 9.

By applying the VCM drive unit 20 of the present embodiment to a portable terminal driven by a battery such as a digital camera, the battery can be held longer or the heat generation in the terminal can be suppressed. is there.

Hereinafter, an example in which the VCM driving unit 20 is applied to a smartphone will be described.

FIG. 6 shows an appearance of a smartphone 200 that is an embodiment of the photographing apparatus of the present invention. A smartphone 200 illustrated in FIG. 6 includes a flat housing 201, and a display input in which a display panel 202 as a display unit and an operation panel 203 as an input unit are integrated on one surface of the housing 201. Part 204 is provided. Such a housing 201 includes a speaker 205, a microphone 206, an operation unit 207, and a camera unit 208. Note that the configuration of the housing 201 is not limited thereto, and for example, a configuration in which the display unit and the input unit are independent can be employed, or a configuration having a folding structure and a slide mechanism can be employed.

FIG. 7 is a block diagram showing a configuration of the smartphone 200 shown in FIG. As shown in FIG. 6, the main components of the smartphone include a wireless communication unit 210, a display input unit 204, a call unit 211, an operation unit 207, a camera unit 208, a storage unit 212, and an external input / output unit. 213, a GPS (Global Positioning System) receiving unit 214, a motion sensor unit 215, a power supply unit 216, and a main control unit 220. As a main function of the smartphone 200, a wireless communication function for performing mobile wireless communication via a base station device BS (not shown) and a mobile communication network NW (not shown) is provided.

The wireless communication unit 210 performs wireless communication with the base station apparatus BS accommodated in the mobile communication network NW according to an instruction from the main control unit 220. Using this wireless communication, transmission and reception of various file data such as audio data and image data, e-mail data, and reception of Web data and streaming data are performed.

The display input unit 204 displays images (still images and moving images), character information, and the like, visually transmits information to the user under the control of the main control unit 220, and detects user operations on the displayed information. A so-called touch panel, which includes a display panel 202 and an operation panel 203.

The display panel 202 uses an LCD (Liquid Crystal Display), an OELD (Organic Electro-Luminescence Display), or the like as a display device.

The operation panel 203 is a device that is placed so that an image displayed on the display surface of the display panel 202 is visible and detects one or more coordinates operated by a user's finger or stylus. When this device is operated with a user's finger or stylus, a detection signal generated due to the operation is output to the main control unit 220. Next, the main control unit 220 detects an operation position (coordinates) on the display panel 202 based on the received detection signal.

As shown in FIG. 6, the display panel 202 and the operation panel 203 of the smartphone 200 exemplified as an embodiment of the photographing apparatus of the present invention integrally constitute a display input unit 204. The arrangement 203 covers the display panel 202 completely.

When such an arrangement is adopted, the operation panel 203 may have a function of detecting a user operation even in an area outside the display panel 202. In other words, the operation panel 203 includes a detection area (hereinafter referred to as a display area) for an overlapping portion that overlaps the display panel 202 and a detection area (hereinafter, a non-display area) for an outer edge portion that does not overlap the other display panel 202. May be included).

Although the size of the display area and the size of the display panel 202 may be completely matched, it is not always necessary to match the two. In addition, the operation panel 203 may include two sensitive areas of the outer edge portion and the other inner portion. Further, the width of the outer edge portion is appropriately designed according to the size of the housing 201 and the like. Furthermore, examples of the position detection method employed in the operation panel 203 include a matrix switch method, a resistance film method, a surface acoustic wave method, an infrared method, an electromagnetic induction method, a capacitance method, and the like. You can also

The call unit 211 includes a speaker 205 and a microphone 206, converts user's voice input through the microphone 206 into voice data that can be processed by the main control unit 220, and outputs the voice data to the main control unit 220. 210 or the audio data received by the external input / output unit 213 is decoded and output from the speaker 205. Further, as shown in FIG. 8, for example, the speaker 205 can be mounted on the same surface as the display input unit 204 and the microphone 206 can be mounted on the side surface of the housing 201.

The operation unit 207 is a hardware key using a key switch or the like, and receives an instruction from the user. For example, as illustrated in FIG. 6, the operation unit 207 is mounted on the side surface of the housing 201 of the smartphone 200 and is turned on when pressed with a finger or the like, and turned off when the finger is released with a restoring force such as a spring. It is a push button type switch.

The storage unit 212 includes a control program and control data of the main control unit 220, application software, address data that associates the name and telephone number of a communication partner, transmitted / received e-mail data, Web data downloaded by Web browsing, The downloaded content data is stored, and streaming data and the like are temporarily stored. The storage unit 212 includes an internal storage unit 217 built in the smartphone and an external storage unit 218 having a removable external memory slot. Each of the internal storage unit 217 and the external storage unit 218 constituting the storage unit 212 includes a flash memory type (hard memory type), a hard disk type (hard disk type), a multimedia card micro type (multimedia card micro type), This is realized using a storage medium such as a card type memory (for example, MicroSD (registered trademark) memory), a RAM (Random Access Memory), a ROM (Read Only Memory), or the like.

The external input / output unit 213 serves as an interface with all external devices connected to the smartphone 200, and communicates with other external devices (for example, universal serial bus (USB), IEEE 1394, etc.) or a network. (For example, the Internet, wireless LAN, Bluetooth (registered trademark), RFID (Radio Frequency Identification), Infrared Data Association (IrDA) (registered trademark), UWB (Ultra Wideband) (registered trademark) ZigBee) (registered trademark, etc.) for direct or indirect connection.

As an external device connected to the smartphone 200, for example, a wired / wireless headset, a wired / wireless external charger, a wired / wireless data port, a memory card (Memory card) connected via a card socket, or a SIM (Subscriber). Identity Module Card / UIM (User Identity Module Card) card, external audio / video equipment connected via audio / video I / O (Input / Output) terminal, external audio / video equipment connected wirelessly, yes / no There are a wirelessly connected smartphone, a wired / wireless personal computer, a wired / wireless PDA, a wired / wireless personal computer, an earphone, and the like. The external input / output unit 213 transmits data received from such an external device to each component inside the smartphone 200, or allows the data inside the smartphone 200 to be transmitted to the external device. Can do.

The GPS receiving unit 214 receives GPS signals transmitted from the GPS satellites ST1 to STn in accordance with instructions from the main control unit 220, executes positioning calculation processing based on the received GPS signals, and calculates the latitude of the smartphone 200 Detect the position consisting of longitude and altitude. When the GPS reception unit 214 can acquire position information from the wireless communication unit 210 or the external input / output unit 213 (for example, a wireless LAN), the GPS reception unit 214 can also detect the position using the position information.

The motion sensor unit 215 includes, for example, a three-axis acceleration sensor, and detects the physical movement of the smartphone 200 in accordance with an instruction from the main control unit 220. By detecting the physical movement of the smartphone 200, the moving direction and acceleration of the smartphone 200 are detected. The detection result is output to the main control unit 220.

The power supply unit 216 supplies power stored in a battery (not shown) to each unit of the smartphone 200 in accordance with an instruction from the main control unit 220.

The main control unit 220 includes a microprocessor, operates according to a control program and control data stored in the storage unit 212, and controls each unit of the smartphone 200 in an integrated manner. In addition, the main control unit 220 includes a mobile communication control function that controls each unit of the communication system and an application processing function in order to perform voice communication and data communication through the wireless communication unit 210.

The application processing function is realized by the main control unit 220 operating according to the application software stored in the storage unit 212. Examples of the application processing function include an infrared communication function for controlling the external input / output unit 213 to perform data communication with the opposite device, an e-mail function for transmitting / receiving e-mails, and a web browsing function for browsing web pages. .

Also, the main control unit 220 has an image processing function such as displaying video on the display input unit 204 based on image data (still image or moving image data) such as received data or downloaded streaming data. The image processing function is a function in which the main control unit 220 decodes the image data, performs image processing on the decoding result, and displays an image on the display input unit 204.

Further, the main control unit 220 executes display control for the display panel 202 and operation detection control for detecting a user operation through the operation unit 207 and the operation panel 203. By executing the display control, the main control unit 220 displays an icon for starting application software, a software key such as a scroll bar, or a window for creating an e-mail. Note that the scroll bar refers to a software key for accepting an instruction to move the display portion of a large image that does not fit in the display area of the display panel 202.

In addition, by executing the operation detection control, the main control unit 220 detects a user operation through the operation unit 207 or accepts an operation on the icon or an input of a character string in the input field of the window through the operation panel 203. Or a display image scroll request through a scroll bar.

Further, by executing the operation detection control, the main control unit 220 causes the operation position with respect to the operation panel 203 to overlap with the display panel 202 (display area) or other outer edge part (non-display area) that does not overlap with the display panel 202. And a touch panel control function for controlling the sensitive area of the operation panel 203 and the display position of the software key.

The main control unit 220 can also detect a gesture operation on the operation panel 203 and execute a preset function in accordance with the detected gesture operation. Gesture operation is not a conventional simple touch operation, but an operation that draws a trajectory with a finger or the like, designates a plurality of positions at the same time, or combines these to draw a trajectory for at least one of a plurality of positions. means.

The camera unit 208 includes configurations other than the external memory control unit 20, the recording medium 21, the display control unit 22, the display unit 23, and the operation unit 14 in the digital camera shown in FIG. The captured image data generated by the camera unit 208 can be recorded in the storage unit 212 or output through the input / output unit 213 or the wireless communication unit 210. In the smartphone 200 illustrated in FIG. 6, the camera unit 208 is mounted on the same surface as the display input unit 204, but the mounting position of the camera unit 208 is not limited thereto, and may be mounted on the back surface of the display input unit 204. .

In addition, the camera unit 208 can be used for various functions of the smartphone 200. For example, an image acquired by the camera unit 208 can be displayed on the display panel 202, or the image of the camera unit 208 can be used as one of operation inputs of the operation panel 203. Further, when the GPS receiving unit 214 detects a position, the position can be detected with reference to an image from the camera unit 208. Furthermore, referring to the image from the camera unit 208, the optical axis direction of the camera unit 208 of the smartphone 200 is determined without using the triaxial acceleration sensor or in combination with the triaxial acceleration sensor. It is also possible to determine the current usage environment. Of course, the image from the camera unit 208 can also be used in the application software.

In addition, the position information acquired by the GPS receiver 214 to the image data of the still image or the moving image, the voice information acquired by the microphone 206 (the text information may be converted into voice information by the main control unit or the like), Posture information and the like acquired by the motion sensor unit 215 can be added and recorded in the recording unit 212, or output through the input / output unit 213 and the wireless communication unit 210.

Also in the smartphone 200 configured as described above, the VCM driving unit 20 of the camera unit 208 performs the processing illustrated in FIGS.

As described above, the following items are disclosed in this specification.

The disclosed VCM driving apparatus is a VCM driving apparatus for driving a voice coil motor, and is connected in series to the first transistor and the second transistor connected in parallel to the DC power source and the first transistor. A third transistor connected in series to the second transistor, and the first transistor, the second transistor, the third transistor, and the fourth transistor are controlled. And a controller for controlling the current flowing through the coil constituting the voice coil motor, and one end of the coil is connected between the first transistor and the third transistor, An end is connected between the second transistor and the fourth transistor, and the first transistor and the second transistor are connected. Star is a bipolar transistor of the N-channel type, respectively, said third transistor and said fourth transistor is a field effect transistor of each N-channel type.

The disclosed mobile terminal includes the VCM driving device and the battery as the DC power source.

In the disclosed portable terminal, the control unit selectively performs PWM control for intermittently controlling the current flowing through the coil and linear control for continuously controlling the current flowing through the coil.

The disclosed portable terminal includes an imaging unit that images a subject through an imaging optical system including an optical system driven by the voice coil motor, and the control unit is an imaging period for displaying a live view image by the imaging unit. The PWM control is performed in the middle, and the linear control is performed during the imaging period for recording on the recording medium.

In the disclosed mobile terminal, the PWM control intermittently applies a voltage to the base terminal of the first transistor or the second transistor with the third transistor or the fourth transistor turned on. Including those that are applied control.

The present invention is particularly convenient and effective when applied to a portable terminal such as a battery-powered digital camera or a cellular phone.

As mentioned above, although this invention was demonstrated by specific embodiment, this invention is not limited to this embodiment, A various change is possible in the range which does not deviate from the technical idea of the disclosed invention.
This application is based on a Japanese patent application filed on October 26, 2012 (Japanese Patent Application No. 2012-236822), the contents of which are incorporated herein.

9 Voice coil motor 20 VCM drive unit 21, 22 N-channel bipolar transistor 23, 24 N-channel MOSFET
25 Current detection resistor 26 Control unit 40 Power supply circuit 90 Coil

Claims

A VCM driving device for driving a voice coil motor,
A first transistor and a second transistor connected in parallel to a DC power source;
A third transistor connected in series to the first transistor;
A fourth transistor connected in series to the second transistor;
A control unit that controls the first transistor, the second transistor, the third transistor, and the fourth transistor to control a current that flows in a coil that constitutes the voice coil motor, and
One end of the coil is connected between the first transistor and the third transistor, the other end of the coil is connected between the second transistor and the fourth transistor;
Each of the first transistor and the second transistor is an N-channel bipolar transistor,
Each of the third transistor and the fourth transistor is a VCM driving device that is an N-channel field effect transistor.
The VCM driving device according to claim 1;
A portable terminal comprising a battery as the DC power source.
The mobile terminal according to claim 2,
The said control part is a portable terminal which selectively performs PWM control which controls the electric current sent through the said coil intermittently, and the linear control which controls continuously the electric current sent through the said coil.
The mobile terminal according to claim 3,
An imaging unit that images a subject through an imaging optical system including an optical system driven by the voice coil motor;
The portable terminal that performs the PWM control during an imaging period for live view image display by the imaging unit and performs the linear control during an imaging period for recording on a recording medium.
The mobile terminal according to claim 3 or 4,
The PWM control is a control device that intermittently applies a voltage to a base terminal of the first transistor or the second transistor in a state where the third transistor or the fourth transistor is turned on. .