CN110441605B - Method for measuring coil resistance of VCM and VCM driving apparatus used for the same - Google Patents

Method for measuring coil resistance of VCM and VCM driving apparatus used for the same Download PDF

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CN110441605B
CN110441605B CN201910325934.5A CN201910325934A CN110441605B CN 110441605 B CN110441605 B CN 110441605B CN 201910325934 A CN201910325934 A CN 201910325934A CN 110441605 B CN110441605 B CN 110441605B
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coil
vcm
current
terminal
output terminal
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CN110441605A (en
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金东元
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Zinitix Co Ltd
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Zinitix Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G01R15/202—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using Hall-effect devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/08—Measuring resistance by measuring both voltage and current
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/14—Measuring resistance by measuring current or voltage obtained from a reference source
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
    • H02P25/032—Reciprocating, oscillating or vibrating motors
    • H02P25/034—Voice coil motors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
    • H02P7/02—Arrangements for regulating or controlling the speed or torque of electric DC motors the DC motors being of the linear type
    • H02P7/025—Arrangements for regulating or controlling the speed or torque of electric DC motors the DC motors being of the linear type the DC motors being of the moving coil type, e.g. voice coil motors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/60—Control of cameras or camera modules
    • H04N23/68—Control of cameras or camera modules for stable pick-up of the scene, e.g. compensating for camera body vibrations
    • H04N23/682—Vibration or motion blur correction
    • H04N23/685—Vibration or motion blur correction performed by mechanical compensation
    • H04N23/687—Vibration or motion blur correction performed by mechanical compensation by shifting the lens or sensor position
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B2205/00—Adjustment of optical system relative to image or object surface other than for focusing
    • G03B2205/0053—Driving means for the movement of one or more optical element
    • G03B2205/0069—Driving means for the movement of one or more optical element using electromagnetic actuators, e.g. voice coils

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Power Engineering (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Control Of Linear Motors (AREA)
  • Measuring Magnetic Variables (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Abstract

A VCM driving apparatus for supplying a driving current to an external coil through a first current input/output terminal and a second current input/output terminal, the VCM driving apparatus including a coil driving unit including 4 transistors and a first current source that together with the coil form an H-bridge circuit, a feedback path for feeding back a potential difference between the first current input/output terminal and the second current input/output terminal, an ADC (analog-to-digital converter), a first switch, and a control unit that controls the first current source so that only one of the 4 transistors is kept in an on state so that a predetermined first measurement current flows through the coil and that controls the first current source so that the first current source outputs the first measurement current, during a mode operation of the VCM driving apparatus in which a resistance value of the coil is measured, and controlling the first switch such that the first switch connects the feedback path to an input terminal of the ADC so that the potential difference is input to the ADC, and calculating a resistance value of the coil based on a value of the first measurement current and the potential difference.

Description

Method for measuring coil resistance of VCM and VCM driving apparatus used for the same
Technical Field
The present invention relates to a VCM driving apparatus for driving a VCM, and more particularly, to a technique capable of measuring and providing a resistance value of a coil included in the VCM.
Background
Fig. 1 shows a structure of a VCM driving apparatus 10 of an embodiment.
The VCM driving apparatus 10 may include a Hall sensor 110, an ADC130, a PID Control section 140, an Output Control section (Output Control) 145, a coil driving section 150, an LDO141, an EEPROM (electrically erasable and programmable read only memory) 142, a BGR143, a Hall Bias voltage driving section (Hall Bias) 160, and an I2C interface 170. The coil driving unit 150 may function to drive a current flowing into a VCM mounted on the autofocus lens. The hall bias current driver 160 may be used instead of the hall bias voltage driver 160.
The VCM driving means 10 may control the movement of a photographing means including a lens and a VCM for adjusting the focal length of the lens. Also, the VCM driving apparatus 10 can sense and correct the position of the lens using the hall sensor 110.
The hall sensor 110 can output a differential signal with respect to the present position of the lens.
The hall offset canceling unit 125 and the amplifying unit 120 may perform a shift function of amplifying the output differential signal and adding a desired value to the value of the differential signal or the amplified differential signal. The hall offset canceling unit 125 and the amplifying unit 120 may have a configuration in which, when the VCM driving device 10 controls the image pickup device, the input range of the ADC130 is used in its entirety without omission, and the specific position of the lens cannot be detected by the ADC130, so that the moving range of the lens in the lens barrel and the input range of the ADC precisely match each other.
The ADC130 may convert the amplified and shifted voltage value Vadc input from the hall offset canceling unit 125 and the amplifying unit 120 into a digital value and output the digital value.
The PID control part 140 may check whether an error occurs with respect to the digital value received from the ADC130, and provide the digital value subjected to the checking process to the output control part 145.
The output control unit 145 may output an output value having a value related to the driving current to be supplied to the VCM, based on the digital value.
The coil driving part 150 may drive the VCM according to the output value of the output control part 145.
The hall bias voltage or current driving part 160 may supply a bias voltage or current required for the operation of the hall sensor 110 to the hall sensor. The sensitivity of the hall sensor 110 may vary depending on the magnitude of the hall bias voltage or current.
The VCM driving apparatus 10 may have a total of 6 input-output terminals. GND192 is a terminal to which a reference potential is input to the VCM driving device 10. The SDA172 is a terminal for data input and output of the I2C communication protocol. SCL171 is a terminal that inputs and outputs a clock based on the I2C communication protocol. VDD191 is a terminal for inputting driving power to the VCM driving device 10. The first current input/output terminal (OUTP) 181 and the second current input/output terminal (OUTN) 182 are a pair of terminals for inputting and outputting the VCM driving current outputted from the VCM driving device 10. The VCM driving current outputted from the first current input/output terminal (OUTP) (or the second current input/output terminal (OUTN)) is inputted again through the second current input/output terminal (OUTN) (or the first current input/output terminal (OUTP)). The first current input output terminal (OUTP) and the second current input output terminal (OUTN) may be connected to both ends of the coil 240 included in the VCM. The VCM driving current may flow through the coil 240.
Fig. 2 shows the appearance and terminals of a VCM210 provided according to an embodiment.
The VCM210 may include said coil 240.
Fig. 2 (a) is a perspective view of the VCM210 according to the embodiment, and fig. 2 (b) shows 4 input/output terminals exposed to the VCM 210. Outside the VCM210, the GND192, SDA172, SCL171, and VDD191 described above may be exposed. The OUTP181 and OUTN182 may not be exposed to the outside of the VCM 210.
FIG. 3 shows an auto-focus lens driving system including one embodiment of VCM and VCM driving means.
The housing 21 may include a lens barrel (lens barrel) 22 having a lens 220 and a magnet 23, a ball (ball) 24 for smoothly moving the lens 220, and a coil 240. The lens 220 is automatically focused as the lens moves up and down.
When the lens is to be moved to the target position, the lens may be moved to the target position by feedback control of the VCM. At this time, for the feedback control, the hall sensor 110 may sense and output a present position value with respect to the present position of the lens 220. Further, the VCM is feedback-controlled until the detected present position value 131, PU is the same as the target position. The target position may be defined on a y-axis as an optical axis of the lens 220, and may have a value from an infinite position (y = 0) to an infinite position (y = 1023).
Fig. 4 shows a configuration diagram of an autofocus lens driving system of an embodiment.
In the VCM driving apparatus 10 of one embodiment, as illustrated in fig. 1, 6 terminals may be provided, that is, SCL171, SDA172, OUTP181, OUTN182, VDD191, and GND192 may be provided.
The VCM driving device 10 may control the operation of the photographing device 20, and the photographing device 20 includes a lens 220, an image sensor 230 for receiving light incident through the lens 220, and a VCM210 for adjusting the focal length of the lens 220. Also, the VCM driving apparatus 10 can sense the position of the lens 220 using the hall sensor 110.
The magnet 250 and the coil 240 may be mounted on the imaging device 20. The magnet 250 may be fixedly disposed on the lens 220. If the driving current I is supplied to the coil 240, the position of the lens 220 may be varied by an electromagnetic force formed between the magnet 250 and the coil 240.
The VCM driving apparatus 10 can receive a command provided from the host 30 through the SCL171 and the SDA 172. Host 30 may provide commands that cause lens 220 focal length to have a value that is consistent with the user's intent. Thus, host 30 may receive user input through user interface 40.
Fig. 5 exemplarily illustrates an operation state of each driving mode of the coil driving part 150 shown in fig. 1.
The coil driving part 150 may include 4 transistors 51, 52, 53, 54 for outputting the driving current I. A coil 240 is connected to the 4 transistors 51, 52, 53, and 54, thereby forming a so-called H-bridge circuit. In fig. 5, not only the 4 transistors 51, 52, 53, and 54 but also the coil 240 are illustrated to aid understanding.
The transistors may be FETs, for example. At this time, the control voltages inputted to the gates of the transistors 51, 52, 53, and 54 can be supplied from the output control unit 145.
As shown in fig. 5, the general coil driving part 150 has 4 modes. The first mode (a) is a standby mode, the second mode (b) and (c) are stop modes, the third mode (d) is a forward current drive mode, and the fourth mode (e) is a backward current drive mode.
With regard to (a) of fig. 5, the 4 transistors 51, 52, 53, 54 each have an off state.
With regard to (b) of fig. 5, only the transistors 51, 52 of the 4 transistors 51, 52, 53, 54 have an off state.
With regard to (c) of fig. 5, only the transistors 53, 54 of the 4 transistors 51, 52, 53, 54 have an off state.
In the case of (d) of fig. 5, only the transistors 52, 53 of the 4 transistors 51, 52, 53, 54 have an off state.
In the case of (e) of fig. 5, only the transistors 51, 54 of the 4 transistors 51, 52, 53, 54 have an off state.
Generally, the operation mode of the coil driving unit 150 is configured by the mode shown in fig. 5, and if a mode different from this is provided, it is intended to achieve another technical object. In the operation mode shown in fig. 5, there is not shown a mode in which only one of the 4 transistors 51, 52, 53, and 54 has an on state.
The above-described VCM driving apparatus 10 may be provided in combination with the VCM 210. For example, the VCM driving device 10 may be provided by being mounted in a housing of the VCM210, and in this case, the VCM driving device 10 may not be exposed outside the housing of the VCM 210. Even in this case, the VCM driving apparatus 10 receives an input power from the outside or a communication channel with the outside, and for this reason, necessary SCL171, SDA172, VDD191, and GND192 terminals may be exposed outside the casing of the VCM 210. In contrast, since the OUTP181 and OUTN182 terminals of the VCM driving apparatus 10 are connected only to the coil 240 in the VCM210, the OUTP181 and OUTN182 terminals do not need to be exposed outside the casing of the VCM 210.
On the other hand, the parameter value stored in the register or the like of the VCM driving device 10 may depend on the resistance value. Therefore, it is necessary to know an accurate resistance value of the coil 240 included in the VCM210 connected to the VCM driving apparatus 10 and used. However, it is desirable that the coil 240 included in the VCM210 used by a specific user equipment has all the same resistance values in an ideal case, but the resistance values thereof are different depending on manufacturing variations. Therefore, it is necessary to provide a method of measuring the resistance value of each coil 240, and therefore, both terminals of the coil 240 or the OUTP181 and OUTN182 terminals connected to both terminals of the coil 240 need to be exposed outside the case of the VCM210, but this configuration cannot be realized for other reasons, and there is a problem that there is no method of measuring the resistance value of each coil 240.
Disclosure of Invention
(technical problem to be solved)
The present invention is intended to provide a technique using a VCM driving device as a method for measuring the resistance of a coil included in a VCM.
The present invention provides a technique for a VCM itself to measure a coil resistance in a state where a coil terminal does not come out to the outside, to manage a coil state and a deviation even at the time of production, and to grasp a coil state even after shipment and even after mounting to a camera module.
(means for solving the problems)
According to an aspect of the present invention, it is possible to provide the VCM driving apparatus 10 which supplies the driving current to the external coil 240 through the first current input/output terminal (OUTP) and the second current input/output terminal (OUTN). The VCM driving apparatus 10 may include: a coil driving unit 150 including 4 transistors 51, 52, 53, and 54 constituting an H-bridge circuit together with the coil, and a first current source 55; a feedback path P1 for feeding back a potential difference between the first current input/output terminal and the second current input/output terminal; an ADC 130; a first switch 19; and a control section. In this case, the control unit may be configured to, during an operation of the VCM driving device in a mode for measuring a resistance value of the coil, control the first current source such that a predetermined first measurement current flows through the coil while only one of the 4 transistors is kept in an on state, control the first current source such that the first current source outputs the first measurement current, and control the first switch such that the first switch connects the feedback path to the input terminal of the ADC such that the potential difference is input to the ADC, and calculate the resistance value of the coil based on a value of the first measurement current and the potential difference.
In this case, the current output terminal of the two terminals of the first current source may be connected to one terminal of the coil through one of the first current input/output terminal and the second current input/output terminal, and the one transistor held in the on state may be the other terminal of the 4 transistors connected to the coil.
In this case, the control unit may control the first current source to output a current having a substantially 0 value or control the first current source to be in a state where the current output terminal of the first current source is not connected to the first current input/output terminal and the second current input/output terminal when the VCM driving device is operated in a mode other than a mode for measuring a resistance value of the coil.
In this case, the VCM driving apparatus may further include a hall sensor voltage supply unit having a hall sensor 110, and the control unit may control the first switch such that the potential difference is not input to the ADC but the output voltage of the hall sensor voltage supply unit is input to the ADC when the VCM driving apparatus is operated in a mode other than a mode in which the resistance value of the coil is measured.
At this time, the VCM driving apparatus may further include: a PID control unit 140 that checks whether or not an error occurs in the digital value received from the ADC; and an output control unit 145 that generates a control signal for controlling the on/off states of the 4 transistors included in the coil driving unit; the control section includes the PID control section or the output control section.
At this time, the VCM driving apparatus may further include: a storage section 142; and a communication interface including a communication clock terminal 171 and a communication data terminal 172. Further, if a predetermined command is received through the communication interface, the control unit switches to a mode for measuring the resistance value of the coil, and stores the calculated resistance value of the coil in the storage unit or supplies the calculated resistance value to the outside through the communication interface.
The storage portion may be an EEPROM.
The communication clock terminal and the communication data terminal may be a serial communication clock terminal and a serial communication data terminal, respectively.
A driving device according to another aspect of the present invention may include: the above-described VCM driving device; and a VCM comprising the coil; the VCM driving apparatus may be mounted in a casing of the VCM, the two terminals of the coil, the first current input/output terminal, and the second current input/output terminal may not be exposed to the outside of the casing of the VCM, and a serial communication clock terminal 171, a serial communication data terminal 172, a power supply terminal VDD, and a reference potential terminal GND formed in the VCM driving apparatus may be exposed to the outside of the casing of the VCM.
(Effect of the invention)
According to the present invention, as a method of measuring the resistance of the coil included in the VCM, a technique using a VCM driving apparatus can be provided.
According to the present invention, a technique can be provided in which the VCM itself measures the coil resistance in a state where the coil terminal does not come out to the outside, the coil state and the variation can be managed even at the time of production, and the state of the coil can be grasped even after shipment and even after the VCM is mounted on a camera module.
Drawings
Fig. 1 shows a structure of a VCM driving apparatus 10 of an embodiment.
Fig. 2 shows the appearance and terminals of a VCM210 provided according to an embodiment.
FIG. 3 shows an auto-focus lens driving system including one embodiment of VCM and VCM driving means.
Fig. 4 shows a configuration diagram of an autofocus lens driving system of an embodiment.
Fig. 5 exemplarily illustrates an operation state of each driving mode of the coil driving part 150 shown in fig. 1.
Fig. 6 shows a structure of a VCM driving apparatus 10 according to an embodiment of the present invention.
Fig. 7 shows a structure of the coil driving part 150 shown in fig. 6.
Detailed Description
Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described in the present specification, and may be embodied in various forms. The terms used in the present specification are used to aid understanding of the embodiments, and are not intended to limit the scope of the present invention. In addition, as used hereinafter, the singular forms also include the plural forms as long as the words do not clearly indicate the opposite meaning.
Fig. 6 shows a structure of a VCM driving apparatus 10 according to an embodiment of the present invention.
The VCM driving apparatus 10 may include a hall sensor 110, an ADC130, a PID control part 140, an output control part 145, a coil driving part 150, an LDO141, a storage part 142, a BGR143, a hall bias voltage driving part 160, and an I2C interface 170. The coil driving unit 150 may function to drive a current flowing into the VCM.
The storage section 142 may be an EEPROM.
The VCM driving apparatus 10 includes the above-described SCL171, SDA172, VDD191, GND192, VCM210, OUTP181, and OUTN 182.
The components suggested in fig. 6 may perform the functions illustrated in fig. 1.
The VCM driving means 10 may control the operation of a photographing means including a lens and a VCM for adjusting the focal length of the lens. Also, the VCM driving apparatus 10 can sense and correct the position of the lens using the hall sensor 110.
The hall sensor 110 can output a differential signal with respect to the present position of the lens.
The hall offset canceling unit 125 and the amplifying unit 120 may perform a shift function of amplifying the output differential signal and adding a desired value to the value of the differential signal or the amplified differential signal. The hall offset canceling unit 125 and the amplifying unit 120 may have a configuration in which, when the VCM driving device 10 controls the image pickup device, the input range of the ADC130 is used in its entirety without omission, and the specific position of the lens cannot be detected by the ADC130, and the moving range of the lens in the lens barrel and the input range of the ADC are precisely matched with each other.
In this specification, a functional unit including the hall sensor 110, the hall offset canceling unit 125, and the amplifying unit 120 may be referred to as a hall sensor voltage supplying unit.
The ADC130 may convert the amplified and shifted voltage value Vadc input from the hall offset canceling unit 125 and the amplifying unit 120 into a digital value and output the digital value.
The PID control part 140 may check whether an error occurs with respect to the digital value received as input from the ADC130, and may provide the digital value subjected to the checking process to the output control part 145.
The output control unit 145 may output an output value having a value related to the driving current to be supplied to the VCM, based on the digital value.
The coil driving part 150 may drive the VCM according to the output value of the output control part 145.
The hall bias voltage or current driving part 160 may supply a bias voltage or current required for the operation of the hall sensor 110 to the hall sensor. The sensitivity of the hall sensor 110 may vary depending on the magnitude of the hall bias voltage or current.
The VCM driving apparatus 10 may have a total of 6 input-output terminals. The GND192 is a terminal to which the reference potential is input to the VCM driving device 10. The SDA172 is a terminal for data input and output of the I2C communication protocol. SCL171 is a terminal for inputting and outputting a clock based on the I2C communication protocol. VDD191 is a terminal for inputting driving power to the VCM driving device 10. Oup 181 and outern 182 are pairs of terminals for inputting and outputting the VCM driving current outputted from the VCM driving device 10. The VCM driving current output from OUTP181 (or OUTN 182) is input again through OUTP 182 (or OUTP 181). OUTP181 and OUTN182 may be connected across coil 240 included in the VCM. The VCM driving current may flow through the coil 240.
On the other hand, if fig. 1 and 6 are compared, the VCM driving apparatus 10 shown in fig. 6 has a plurality of different configurations, and first, the VCM driving apparatus further includes the first switch 19, second, the feedback path P1 for supplying the voltage difference between the OUTP and OUTN nodes to the input terminal of the ADC130, and third, the configuration of the coil driving unit 150 is changed. This will be explained with reference to fig. 6 and 7.
Fig. 7 shows a structure of the coil driving part 150 shown in fig. 6.
The coil driving part 150 may include 4 transistors 51, 52, 53, 54 for outputting the driving current I. The 4 transistors 51, 52, 53, and 54 may be connected with a coil 240 located outside the coil driving unit 150, thereby forming a so-called H-bridge circuit. In fig. 7, not only the 4 transistors 51, 52, 53, and 54 but also the coil 240 are illustrated to assist understanding.
The two terminals OUT1, OUT2 connected to the coil 240 in the coil driver 150 may be electrically the same nodes as the OUTP181 and OUTN182 that are input/output terminals of the VCM driving device 10.
In addition, the coil driving part 150 further includes a first current source 55 supplying a direct current. The user can adjust the value of the dc current output by the first current source 55.
The current output terminal of the two terminals of the first current source 55 may be connected to the first terminal OUT1 of the coil driving unit 150 as shown in fig. 7 (a), or connected to the second terminal OUT2 of the coil driving unit 150 as shown in fig. 7 (b).
The coil driving unit 150 shown in fig. 7 may have first to fourth modes, i.e., a standby mode, a stop mode, a forward current driving mode, and a backward current driving mode, as shown in fig. 5.
Further, the coil driving section 150 shown in fig. 7 may further have a coil resistance measurement mode as a fifth mode.
With the first to fourth modes, the output control section 145 may control the coil driving section 150 such that the first current source 55 outputs a value of 0 (zero) [ a ]. Alternatively, with the first to fourth modes, the output control section 145 may control the coil driving section 150 so as to operate as if the first current source 55 is not present.
During operation in the fifth mode, i.e., during operation in the coil resistance measurement mode, the VCM driving device 10 can be controlled as follows.
First, it is possible to control such that the first current source 55 supplies the first measurement current I as a constant current having a predetermined value to one terminal (for example, the first terminal OUT1 or the second terminal OUT 2) of the coil drive section 150 connected to the two terminals of the coil 240 existing outside the coil drive section 150M. The control signal for such control may be generated and output by the output control unit 145, the PID control unit 140, or another control unit not shown.
Second, the first measurement current I is provided at a first current source 55MMeanwhile, that is, during the operation in the coil resistance measurement mode, one of the two transistors connected to the other of the two terminals (for example, the second terminal OUT2 or the first terminal OUT 1) is kept in an ON state, so that the first measurement current I can be made to be the first measurement current IMCan flow through the coil 240 and the one transistor. For example, one of the two transistors may be a transistor connected to the reference potential GND. The control signal for such control may be generated and output by the output control unit 145 or another control unit not shown.
Third, the first measurement current I is provided at a first current source 55MIn the meantime, that is, during the operation in the coil resistance measurement mode, the other 3 transistors except the one transistor among the 4 transistors 51 to 54 included in the coil driving unit 150 may be controlled to have an off state. The control signal for such control may be generated and output by the output control unit 145 or another control unit not shown.
Fourth, during operation in the coil resistance measurement mode, the first switch 19 may be controlled such that the differential input terminal of the ADC19 is connected to the feedback path P1. In contrast, during the operation in the first to fourth modes other than the coil resistance measurement mode, the first switch 19 may be controlled so as to connect the differential input terminal of the ADC19 to the output terminal of the amplifying section 120. Alternatively, the first switch 19 may connect the differential input terminal of the ADC19 to the output signal side of the hall sensor 110 during operation in the first to fourth modes other than the coil resistance measurement mode. The control signal for such control may be supplied to the first switch 19, and may be generated and output by the PID control unit 140 or another control unit not shown.
In one embodiment, the first switch 19 may provide only two connection modes connecting the differential input terminal of the ADC19 to the feedback path P1 or to the output signal side of the hall sensor 110.
The feedback path P1 may be configured by 2 signal lines connected to a terminal (OUTP) and a terminal (OUTN) of input/output terminals of the VCM driving device 10, which supply a driving current to the coil 240. At this time, the terminal (OUTP) and the terminal (OUTN) of the VCM driving device 10 are electrically the same nodes as the first terminal OUT1 and the second terminal OUT2 of the first current source 55. Thus, as shown in fig. 7, the feedback path P1 may also behave as if it were from the first current source 55. The feedback path P1 is used to supply the potential difference between the terminals (OUTP) and (OUTN), and thus the specific method for forming the feedback path P1 can be variously provided and can be provided according to the usual attachment capability of a practitioner.
Fifth, during operation in the coil resistance measurement mode, the ADC130 may output a first measurement voltage V with respect to the voltage across the coil 240 as a voltage obtained through the feedback path P1M. In this case, the PID control unit 140 or another control unit not shown may use the first measured current I having the predetermined valueMAnd said first measurement voltage VMThe resistance value of the coil 240 is calculated. Alternatively, the first measurement current IMIs a predetermined value, and therefore the PID control unit 140 or the other control unit not shown can use the first measurement voltage VMThe resistance value of the coil 240 is calculated.
When power is supplied to the VCM driving apparatus 10, the VCM driving apparatus 10 is in one of the above-described 5 modes or another additional mode. At this time, in order for the VCM driving apparatus 10 to switch the mode to operate in the coil resistance measurement mode, the user may issue a mode switching command through the user interface 40. The host 30 may communicate such user commands to the VCM driver 10 through the SCL171 and SDA172 terminals of the VCM driver 10 using I2C communication protocol.
The resistance value of the coil 240 calculated by operating the VCM driver 10 in the coil resistance measurement mode may be stored in the EEPROM142 and/or transmitted to the host 30 and the user interface 40 using the I2C communication protocol. The stored resistance value may be used for parameter setting of the VCM driving apparatus 10. The function of storing or transmitting the calculated resistance value of the coil 240 may be executed by the PID control unit 140, the output control unit 145, or another control unit not shown.
If the input dynamic range of ADC130 is assumed to be a volts and the resolution of the ADC is N-bit resolution, the AND/2 can be calculatedN1 LSB corresponding ADC input voltage of 1 volt.
The first current source 55 can variably function as a constant current source. When set to output b amps by the first current source 55, if the ADC130 output code representing the potential difference between the first terminal OUT1 and the second terminal OUT2 is assumed to be c LSB, the resistance value r of the coil 240 may be determined to be r = c a/2N -1 / b。
For example, when assuming an input dynamic range of ADC130 of 1 volt and ADC130 of 10-bit ADC, an ADC input voltage corresponding to 1 LSB of 1000mV/1023LSB may be calculated.
Also, when the output value of the first current source 55 is set to 1mA, if it is assumed that the ADC130 output code representing the potential difference between the first terminal OUT1 and the second terminal OUT2 is 30 LSB, then at this time, the resistance value of the coil 240 may be determined to be 30 × 1000 mV/1023/1 mA = 29.3255 ohm.
When configured as shown in fig. 7 (a), if the ADC130 output code representing the potential difference between the first terminal OUT1 and the second terminal OUT2 has a positive value, the ADC130 output code representing the potential difference between the first terminal OUT1 and the second terminal OUT2 has a negative value when configured as shown in fig. 7 (a).
With the embodiments of the present invention described above, those skilled in the art of the present invention can easily make various changes and modifications without departing from the essential characteristics of the invention. The contents of the claims may be combined with other claims not referred to within the scope of the description, which is understood from the present description.

Claims (6)

1. A VCM driving device for supplying a driving current to an external coil through a first current input/output terminal and a second current input/output terminal,
comprises a coil driving part with a first current source and an ADC;
during operation of the VCM driving apparatus in a mode in which the VCM driving apparatus measures the resistance value of the coil, firstly, the first current source is controlled so that a predetermined first measurement current flows through the coil, secondly, a potential difference between the first current input/output terminal and the second current input/output terminal is input to the ADC, and thirdly, the resistance value of the coil is calculated based on the potential difference;
controlling so that the first current source outputs a current having substantially a value of 0 or in a state where the current output terminal of the first current source is not connected to the first current input-output terminal and the second current input-output terminal when the VCM drive device operates in a mode other than a mode in which the resistance value of the coil is measured,
wherein the content of the first and second substances,
the coil driving part further includes a plurality of transistors constituting an H-bridge circuit together with the coil,
during the operation of the VCM driving apparatus in the mode in which the resistance value of the coil is measured, firstly only one transistor of the plurality of transistors is kept in an on state, and secondly a current output terminal of two terminals of the first current source is connected to one terminal of the coil through either one of the first current input-output terminal and the second current input-output terminal,
the one transistor kept in an on state is one of the plurality of transistors connected to the other terminal of the coil during operation of the VCM driving device in a mode in which a resistance value of the coil is measured.
2. The VCM driving apparatus of claim 1, wherein,
a current output terminal of the two terminals of the first current source is connected to one terminal of the coil through one of the first current input/output terminal and the second current input/output terminal,
during operation of the VCM driving apparatus in a mode in which the resistance value of the coil is measured, the other terminal of the coil is connected to an arbitrary current path so that the first measurement current flows through the coil.
3. The VCM driving apparatus of claim 1, wherein,
further comprising: a feedback path that feeds back a potential difference between the first current input/output terminal and the second current input/output terminal; a Hall sensor voltage supply section including a Hall sensor; and a first switch;
controlling the first switch such that the first switch connects the feedback path to the input terminal of the ADC during operation of the VCM driving means in a mode in which the resistance value of the coil is measured, so that the potential difference is input to the ADC, and,
when the VCM driving device is operated in a mode other than the mode for measuring the resistance value of the coil, the first switch is controlled so that the potential difference is not input to the ADC and the output voltage of the hall sensor voltage supplying section is input to the ADC.
4. The VCM driving apparatus of claim 1, wherein,
the coil driving part further includes a plurality of transistors constituting an H-bridge circuit together with the coil,
the VCM driving apparatus further includes:
a PID control unit that checks whether or not an error occurs in the digital value received from the ADC; and
and an output control unit that generates a control signal for controlling the on/off states of the plurality of transistors included in the coil drive unit.
5. The VCM driving apparatus according to claim 1, further comprising:
a storage unit; and
a communication interface including a communication clock terminal and a communication data terminal;
if a predetermined command is received through the communication interface, causing a transition to a mode of measuring the resistance value of the coil,
and storing the calculated resistance value of the coil in the storage unit, or supplying the resistance value to the outside through the communication interface.
6. A current drive device comprising:
a VCM driving means of one of claims 1 to 5; and
a VCM comprising the coil;
the VCM driving means is mounted within a housing of the VCM,
two terminals of the coil, the first current input-output terminal and the second current input-output terminal are not exposed outside a case of the VCM,
the communication clock terminal, the communication data terminal, the power supply terminal, and the reference potential terminal formed in the VCM driving device are exposed to the outside of the housing of the VCM.
CN201910325934.5A 2018-05-03 2019-04-15 Method for measuring coil resistance of VCM and VCM driving apparatus used for the same Active CN110441605B (en)

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