KR102044213B1 - A closed-loop method for restricting VCM moving area, VCM driving device for the same, lens module for user device for the same, and user device for the same - Google Patents

Abstract

By varying the linear position of the lens with respect to the variation of the VCM driving current in the barrel to correspond to the entire output range of the ADC, the moving distance per code output from the ADC can be kept constant and the accuracy of the lens position control can be improved. Reveal the VCM drive

Description

A closed-loop control method for limiting the VCM driving range, a VCM driving device for the same, a lens module for a user device for the same, and a user device therefor {A closed-loop method for restricting VCM moving area, VCM driving device for the same, lens module for user device for the same, and user device for the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device, and more particularly, to a technology for controlling a driving range of a voice coil motor (VCM) for driving a lens within a linear region.

Some of the optical lenses (hereinafter, simply lenses) mounted on the user device are automatically adjusted in focus. The lens may be equipped with a voice coil motor (VCM) for auto focus adjustment. According to this configuration, when a current flows through the VCM, the focal length is adjusted while the lens moves along the optical axis direction (that is, the moving direction of the lens in the barrel). When the lens is at the bottom position of the barrel (bottom, ie macro position), focus is formed at the minimum focal length according to the lens design, and when the lens is at the ceiling position of the barrel (top, ie, infinity position), the furthest infinity Focus may be formed at a distance.

A magnet (magnetic) and a coil may be installed in the imaging device including the lens. In this case, the magnet may be fixedly disposed on the lens. When a current flows through the VCM, a driving current is provided to the coil, and the position of the lens may be changed by an electromagnetic force generated between the magnet and the coil.

In the technique of controlling the lens position in a feedback manner, the driving device for driving the VCM may include a hall sensor configured to detect the position of the lens.

The hall sensor may detect a magnetic force of a magnet disposed in the lens and output a voltage value regarding the position of the lens. The voltage output from the Hall sensor can be amplified and then input to the ADC.

For example, when the ADC outputs n bits of digital values, the ADC may have an output range of 0 to 2 ⁿ −1, for example. The position in the barrel of the lens can be adjusted based on the output value of the ADC.

For example, when the ADC is to export a 10-bit output, ideally, when it is the ADC outputs a value of 0, the lens is located at the bottom of the column, when it is the ADC outputs a value of 1023 (2 ¹⁰ - 1) of the lens barrel It can be located on the ceiling.

On the other hand, when the lens is in a certain range from the bottom position of the barrel and a certain range from the ceiling position of the barrel, there is a problem that the linearity of the change in the moving distance of the lens with respect to the change in the current provided to the VCM is not guaranteed. At this time, the first boundary position closest to the floor position and the second boundary position closest to the ceiling position are defined among the linear regions, which are regions in which the linearity of the change in the moving distance of the lens with respect to the change in the current provided to the VCM is guaranteed. Can be. The lens can now be designed to be used only in the linear region. In this case, it is conceivable that the ADC still outputs 0 when the lens is in the bottom position, and still outputs 2 ⁿ −1 when the ADC is in the ceiling position. In this case, when the lens is located at the first position, the ADC will output a value of (0 + a) (a is a positive integer), and when the lens is located at the second position, the ADC will (2 ⁿ -1). -b) (b is a positive natural number) That is, the output of the ADC will be limited in the range of (0 + a) to (2 ^n- 1-b) when the lens is in the linear region actually used. That is, (0) to (0 + a-1), and (2 ^n- 1-b + 1) to (2 ⁿ -1) of the output range that the ADC can provide will be discarded without being used. As a result, when a portion of the input range of the ADC is not available, the resolution of the measured value measured by the lens position is reduced.

The above description is provided to help the understanding of the present invention, and not all of the above contents are necessarily admitted to be prior art to the present invention.

In the present invention, by matching the minimum and maximum positions of the linear section to ensure the linearity of the change in the moving distance of the lens with respect to the change in the current provided to the VCM of all the available section of the barrel corresponding to the minimum and maximum of the output range of the ADC, An object of the present invention is to provide a VCM driving distance control device capable of increasing the accuracy of lens position measurement while maintaining a constant amount of lens position change according to a change in current provided to the VCM.

According to an aspect of the present invention, there is provided a VCM driving device comprising: a driving unit providing a driving current to a VCM for driving a lens that is to move from a bottom position to a ceiling position of a barrel; A Hall sensor for outputting a differential signal representing the current position of the lens; A matched signal generation unit configured to receive the differential signal and generate a matched signal provided to an input terminal of the ADC; The ADC for converting the matched signal into a digital value; And an output controller configured to control the driver based on the digital value. In this case, the matching signal has a first voltage which causes the ADC to output the smallest output code among the allowable input voltages of the ADC when the lens is in a first boundary position higher than the bottom position, and the lens is operated in the lens. It has a second voltage which causes the ADC to output the largest output code among the allowable input voltages of the ADC when in the second boundary position lower than the ceiling position. In this case, the first boundary position and the second boundary position may be different positions on the optical axis of the lens.

In this case, the output control unit is configured to control the lens to move in a linear region from the first boundary position to the second boundary position, wherein the linear region of the lens with respect to the change of current provided to the VCM. The movement distance change is constant, and in the region other than the linear region, the movement distance change of the lens with respect to the change of the current provided to the VCM may not be constant according to the position of the lens.

In this case, the matched signal generator includes a level shifter for generating a shift voltage by shifting the differential signal and an amplifier for amplifying the shift voltage, and the level shifter shifts the value of the differential signal by a predetermined value. And generating the shift voltage, wherein the amplifier is configured to generate a second value of the shift voltage when the lens is in the second boundary position and a shift value of the shift voltage when the lens is in the first boundary position. The first difference value with the first value may have an amplification factor such that the first difference value is equal to the second difference value between the second voltage and the first voltage.

The matched signal generator may include an amplifier for amplifying the differential signal to generate a second amplified signal and a level shifter to shift the second amplified signal to generate the matched signal. The first difference value between the second value of the second amplified signal when in the second boundary position and the first value of the second amplified signal when the lens is in the first boundary position is determined. An amplification factor that is equal to a second difference value between the second voltage and the first voltage, wherein the level shifter shifts the first value of the second amplified signal when the lens is in the first boundary position; To apply a shift level that is equal to the first voltage.

According to another aspect of the present invention, a VCM driving device includes: a hall sensor for outputting a differential signal indicating a current position of a lens intended to move from a bottom position to a ceiling position of a barrel; A matched signal generation unit configured to receive the differential signal and generate a matched signal provided to an input terminal of the ADC; And the ADC for converting the matched signal into a digital value. In this case, the matching signal has a first voltage which causes the ADC to output the smallest output code among the allowable input voltages of the ADC when the lens is in a first boundary position higher than the bottom position, and the lens is operated in the lens. It has a second voltage which causes the ADC to output the largest output code among the allowable input voltages of the ADC when in the second boundary position lower than the ceiling position. In this case, the first boundary position and the second boundary position may be different positions on the optical axis of the lens.

A lens module for a user device provided according to another aspect of the present invention includes the VCM driving device.

A user device provided according to another aspect of the present invention includes a lens module for the user device.

According to the present invention, the minimum and maximum positions of the linear section where the linearity of the change in the moving distance of the lens with respect to the change in the current provided to the VCM during all the available sections of the barrel correspond to the minimum and maximum values of the output range of the ADC. It is possible to provide a VCM driving distance control device capable of increasing the precision of lens position measurement while maintaining a constant amount of lens position change according to a change in current provided to the VCM.

1 illustrates a structure of a VCM driving apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram for describing a procedure of correcting a differential signal output from a hall sensor included in a VCM driving device to match an input range of an ADC according to a comparative embodiment.
Figure 3 compares the voltage provided to the ADC according to the prior art with the voltage provided to the ADC according to an embodiment of the present invention.
FIG. 4 is a diagram for describing a method of matching a linear region in which linearity of a position change of a lens with respect to a change in current provided to the VCM is matched to the entire code range of the ADC according to the first embodiment of the present invention.
FIG. 5 is a diagram for describing a method of matching a linear region in which linearity of a position change of a lens with respect to a change in current provided to a VCM is matched to the entire code range output by the ADC according to the second embodiment of the present invention. to be.
6 is a graph for comparing the effects according to the first embodiment or the second embodiment with the effects according to the comparative example.
7 is a configuration diagram of a VCM driving apparatus according to another embodiment of the present invention.
FIG. 8 is a diagram for describing a method of matching a linear region in which linearity of a change in position of a lens with respect to a change in current provided to a VCM is matched to the entire code range of an ADC according to a third embodiment of the present invention.
FIG. 9 is a diagram for describing a method of matching a linear region in which linearity of a position change of a lens with respect to a change in current provided to a VCM is matched to the entire code range output by the ADC according to the fourth embodiment of the present invention. to be.
10 is a configuration diagram of a VCM driving apparatus according to another embodiment of the present invention.
FIG. 11 shows the internal structure of the matched signal generation unit of the VCM driving apparatus shown in FIG.

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention will be described. However, the present invention is not limited to the embodiments described herein and may be implemented in various other forms. The terminology used herein is for the purpose of understanding the embodiments and is not intended to limit the scope of the invention. Also, the singular forms used below include the plural forms unless the phrases clearly indicate the opposite meanings.

<Structure of VCM Driving Device According to One Embodiment of the Present Invention>

1 shows the structure of a VCM driving device 10 according to an embodiment of the present invention.

The structure shown in FIG. 1 can be used to explain the comparative examples as well as the examples according to the present invention.

The VCM driving device 10 includes a Hall sensor 110, a level shifting unit 115, an amplifier 120, an ADC 130, a PID control unit 140, an output control unit 145. ), A coil driver 150, an LDO 141, an EEPROM 142, a BGR 143, a hall bias voltage driver (Hall Bias) 160, and an I 2 C interface 170.

Functions of the level shifting unit 115 and the amplifier 120 may be referred to as a matched signal generation unit 12. In the matched signal generator 12, as shown in FIG. 1, the level shifter 115 may precede the amplifier 120, but otherwise the level shifter as shown in FIG. 115 may follow the amplifier 120.

The VCM driving device 10 may control the operation of the image capturing apparatus including the lens and the VCM for adjusting the focal length of the lens. In addition, the VCM driving apparatus 10 may use a closed-loop method using feedback, which detects and corrects the position of the lens using the hall sensor 110.

The hall sensor 110 may output a differential signal regarding a current position of the lens. In this case, the sensitivity of the output to the input of the Hall sensor 110 may be changed according to the Hall sensor bias current provided to the Hall sensor 110. That is, the magnitude of the differential signal output from the hall sensor 110 is a bias provided by the hall bias voltage driver 160 to the hall sensor 110 when the physical quantity input to the hall sensor 110 is constant. It can be changed linearly in proportion to the current (bias current).

The amplifier 120 may be configured to receive and amplify the differential signal.

The ADC 130 may convert the voltage value input from the amplifier 120 into a digital value and output the digital value.

The PID controller 140 may check whether an error has occurred with respect to the digital value input from the ADC 130, and may provide the digital value that has undergone the check process to the output controller 145.

The output controller 145 may output an output value having a value relating to a driving current to be provided to the VCM according to the digital value.

The coil driver 150 may drive the VCM according to the output value of the output controller 145.

The hall bias voltage driver 160 may provide a bias voltage for the operation of the hall sensor to the hall sensor.

Hall sensor feedback voltage processing method according to a comparative embodiment

FIG. 2 is a view for explaining a procedure of correcting a differential signal output from the hall sensor 110 included in the VCM driving apparatus 10 to match the input range of the ADC 130 according to a comparative embodiment.

The present comparative example is provided as a prerequisite knowledge to aid understanding of the embodiments of the present invention, and is also provided for the comparison of the configuration and effects with the embodiments of the present invention. Naturally, this comparative example is not recognized as a prior art.

2 represents the position P of the lens in the barrel 20, and the vertical axis represents the voltage value V. In FIG.

At this time, the magnitude Vdiff of the differential signal is the difference between the output voltage V + at the first output node N1 and the output voltage V− at the second output node N2 of the Hall sensor 110. Can be given as a value.

2A illustrates a voltage value V + output from the first output node N1 of the hall sensor 110 and a voltage value output from the second output node N2 according to the position P of the lens. V-) is shown.

FIG. 2B shows the voltage output from the second output node N2 at the voltage value V + output from the first output node N1 shown in FIG. 2A for each position of the lens. A value obtained by subtracting the value V- represents the magnitude of the differential signal Vdiff.

FIG. 2C is a graph of the graph shown in FIG. 2B, that is, a graph of the magnitude Vdiff of the differential signal so that the minimum value (-2α) of the graph shown in FIG. 2B is converted to 0. The voltage Vs shifted by + 2α is shown. The shift may be performed by the level shifter 115.

In FIG. 2D, the minimum value 0 and the maximum value 4α of the voltage Vs shown in FIG. 2C are equal to the minimum value 0 and the maximum value 8α of the input range of the ADC, respectively. The voltage (Vg) obtained by amplifying twice the magnitude of the graph shown in FIG. The amplification may be performed by the amplifier 120.

As shown in FIG. 2A, the graph of the output voltage V + at the first output node N1 has a Vcom-α value when the lens is positioned at the bottom of the barrel 20. It may be considered that the lens has a value of Vcom + α when the lens is positioned T on the ceiling of the barrel 20. The graph of the output voltage V− at the second output node N2 has a Vcom + α value when the lens is positioned at the bottom of the barrel 20, and the lens is positioned at the ceiling of the barrel. In the case of T), a case having a Vcom-α value may be considered. In this case, the voltage value at the intersection point of the graph of the output voltage V + of the first output node N1 and the graph of the output voltage V− of the second output node N2 may be Vcom.

In this case, the magnitude of the differential signal Vdiff according to the position of the lens may be the same as the graph shown in FIG. That is, the differential signal Vdiff may have a value of -2α at the floor position B and a value of + 2α at the ceiling position T.

The graph of the differential signal Vdiff is shifted to correct the minimum voltage (-2α) of the differential signal Vdiff output from the hall sensor 110 to match the minimum voltage (0) of the allowable input of the ADC 130. Can be. Then, as illustrated in FIG. 2C, a shifted signal Vs having a value of 0 at the bottom position B and a value of + 4α at the ceiling position T may be generated.

Thereafter, for example, if the minimum voltage of the input range of the ADC 130 is 0 and the maximum voltage is + 8α, the matched signal Vg formed by amplifying the shifted signal Vs shown in FIG. Can be provided.

2D is a graph showing the matching signal Vg. Through this graph, when the lens is at the bottom position B of the barrel 20, the input terminal of the ADC 130 is input with the minimum value (0) of the input range allowable by the ADC 130, and the ceiling position (T). ), The maximum value (+ 8α) of the input range allowable by the ADC 130 is input to the input terminal of the ADC 130. That is, the total moving distance B to T where the lens is movable is matched to the full codes defined by the set of digital output values output by the ADC.

In general, when the total moving section (B ~ T) of the lens in the barrel (20) to match the full code (Full Code) output by the ADC 130, a predetermined range from the bottom position (B) of the barrel The range from the ceiling position (T) of the barrel and the linearity may not be guaranteed. If the linearity is not guaranteed, the system complexity may be increased because the precision of the VCM drive is reduced or a correction unit for correcting the same has to be added.

<First embodiment of the present invention>

In the present invention, in order to increase the precision of the VCM driving apparatus, of the positions (B to T) that the lens may have in the barrel 20, the linearity of the change of the position of the lens with respect to the change of the current provided to the VCM is maintained. Only linear regions B + D1 to T-D2 defined as a set of positions may be used. In addition, when the lens is located at a first boundary position B + D1 of two boundary positions of the linear regions B + D1 to T-D2, the lens is generated from a differential signal output from the hall sensor 110. The value is changed to be equal to the minimum value (0) of the allowable input of the ADC, and the hall sensor 110 when the lens is located at the second boundary position T-D2 of the two boundary positions of the linear region. By changing the value generated from the differential signal output from the same value as the maximum value (+ 8α) of the allowable input of the ADC, the precision of the measured value of the position of the lens can be maintained to the maximum. That is, the moving section (B + D1 to T-D2) of the lens, which guarantees linearity of the VCM driving device (= actuator mechanism), is within the full code range defined by all digital values output from the ADC 130. Can be matched.

D1 is a value representing a distance spaced upward from the bottom position (B) of the barrel, and D2 is a value representing a distance spaced downward from the ceiling position (T) of the barrel. D1 and D2 may be the same or different.

Figure 3 compares the voltage provided to the ADC according to the prior art with the voltage provided to the ADC according to an embodiment of the present invention. The horizontal axis of the graph of FIG. 3 represents the position in the barrel of the lens, and the vertical axis represents the magnitude of the voltage provided to the input of the ADC.

The graph G1 shows a range of desirable values that the input voltage of the ADC should have when the actual moving section of the lens is designed to include both the bottom B of the barrel and the ceiling T of the barrel.

In contrast, when the graph G2 is designed such that the total moving section of the lens includes only the minimum position B + D1 where linearity is guaranteed to the maximum position T-D2 where linearity is guaranteed, the input voltage of the ADC This shows the range of the preferred pack that should have.

Hereinafter, a method of matching the intervals B + D1 to T-D2 with guaranteed linearity to the entire code range of the ADC will be described. Here, the entire code may mean a set of minimum to maximum values output by the ADC. The matching may also mean that the ADC outputs a minimum value when the lens is at the position B + D1 and the ADC outputs a maximum value when the lens is at the position T-D2. .

FIG. 4 shows a linear region (B + D1 to T-D2) in which the linearity of the positional change of the lens with respect to the change in current provided to the VCM is matched to the entire code range of the ADC according to the first embodiment of the present invention. It is a figure for demonstrating the method.

The horizontal axis of the graph of FIG. 4 represents the position of the lens in the barrel, and the vertical axis represents the magnitude of the voltage output from the two output terminals of the hall sensor.

In the first embodiment, the response sensitivity of the Hall sensor 110 according to the position of the lens is controlled. To this end, the Hall bias voltage driver 160 may be provided to provide a bias voltage to the Hall sensor 110.

That is, in the first embodiment, the range of the voltage output from the hall sensor 110 may be matched to a section in which linearity is guaranteed from the beginning. That is, by increasing or decreasing the bias voltage Vb output from the hall bias voltage driver 160, the range of the voltage output from the hall sensor 110 may be matched to a section in which linearity is guaranteed from the beginning. Specifically, it is as follows.

As shown in FIG. 4A, the output voltage V + at the first output node N1 of the hall sensor 110 is equal to the first boundary position of the linear region B + D1 to T-D2. The bias voltage Vb can be controlled to be Vb2 so as to have Vcom-α at B + D1) and Vcom + α at the second boundary position T-D2. At this time, when the bias voltage Vb has Vb2, the output voltage V- at the second output node N2 of the hall sensor 110 is the first of the linear regions B + D1 to T-D2. At the boundary position B + D1, it has Vcom + α and at the second boundary position T-D2, it has Vcom-α.

4B is obtained by subtracting the voltage value V− output from the second output node N2 from the voltage value V + output from the first output node N1 shown in FIG. 4A. As a value, it represents the magnitude of the differential signal (Vdiff). The differential signal Vdiff may have a value of -2α at the first boundary position B + D1 and a value of + 2α at the second boundary position T-D2.

FIG. 4C is a graph of the graph shown in FIG. 4B, that is, a graph about the magnitude of the differential signal Vdiff so that the minimum value (-2α) of the graph shown in FIG. 4B is converted to 0. The voltage Vs shifted by + 2α. The shifted voltage Vs may have a value of 0 at the first boundary position B + D1 and a value of + 4α at the second boundary position T-D2.

In FIG. 4D, the minimum value 0 and the maximum value 4α of the voltage Vs shown in FIG. 4C are respectively the minimum value 0 and the maximum value 8α of the input range of the ADC 130. The voltage Vg obtained by amplifying twice the magnitude of the graph shown in FIG. Accordingly, when the lens is located at the first boundary position B + D1 of the barrel 20, the minimum value (0) of the input range allowable by the ADC 130 is input to the input terminal of the ADC 130. In the case of the second boundary position T-D2, the maximum value (+ 8α) of the input range that the ADC 130 can accept is input to the input terminal of the ADC 130. That is, the total codes in which the linear region B + D1 to T-D2 in which the linearity is maintained among the total moving sections B to T where the lens is movable are defined as a set of digital output values output by the ADC 130 are included. Matches (Full Codes).

Second Embodiment

FIG. 5 illustrates that the ADC 130 outputs a linear region (B + D1 to T-D2) in which the linearity of the position change of the lens with respect to the change in the current provided to the VCM is ensured according to the second embodiment of the present invention. A diagram for describing a method of matching the entire code range.

The horizontal axis of the graph of FIG. 5 represents the position of the lens in the barrel, and the vertical axis represents the magnitude of the voltage.

As shown in FIG. 5A, the output voltage V + at the first output node N1 of the hall sensor 110 has Vcom-α at the bottom position B of the barrel 20, and the ceiling At the position T, the bias voltage Vb may be controlled to be Vb1 to have Vcom + α. In this case, when the bias voltage Vb has Vb1, the output voltage V− at the second output node N2 of the hall sensor 110 has Vcom + α at the bottom position B, and the ceiling At position T it has Vcom-α.

5B is obtained by subtracting the voltage value V− output from the second output node N2 from the voltage value V + output from the first output node N1 shown in FIG. 5A. As a value, it represents the magnitude of the differential signal (Vdiff). The differential signal Vdiff may have a value of −2α at the bottom position B and a value of + 2α at the ceiling position T. FIG.

At this time, the value of the differential signal Vdiff has a value of −2α + β ₁ at the first boundary position B + D1 of the linear region B + D1 to T-D2 and the second boundary position T -D2) may have a value of + 2α-β ₂ . β ₁ and β ₂ may be values associated with D1 and D2, respectively. And be a value same _as β ₁ and β ₂ is standing and can be a value different from each other.

FIG. 5C shows the value of the differential signal Vdiff (-2α + β) when the lens position is at the first boundary position B + D1 of the linear region B + D1 to T-D2. _The voltage Vs obtained by shifting the graph shown in (b) of FIG. 5, that is, the graph of the magnitude Vdiff of the differential signal by +2 alpha-beta ₁ so that ₁ ) is converted to 0. The shifted voltage Vs may have a value of 0 at the first boundary position B + D1 and a value of + 4α-β ₂ -β ₁ at the second boundary position T-D2. have.

FIG. 5D shows a value 0 at the first boundary position B + D1 and a value at the second boundary position T-D2 among the voltages Vs shown in FIG. 5C. The size of the graph shown in FIG. 5C is 8α / (such that + 4α-β ₂ -β ₁ is equal to the minimum value 0 and the maximum value 8α of the input range of the ADC 130, respectively. The voltage (Vg) obtained by amplifying + 4α-β ₂ -β ₁ ) is shown. Accordingly, when the lens is located at the first boundary position B + D1 of the barrel 20, the minimum value (0) of the input range allowable by the ADC 130 is input to the input terminal of the ADC 130. In the case of the second boundary position T-D2, the maximum value (+ 8α) of the input range that the ADC 130 can accept is input to the input terminal of the ADC 130. That is, the total codes in which the linear region B + D1 to T-D2 in which the linearity is maintained among the total moving sections B to T where the lens is movable are defined as a set of digital output values output by the ADC 130 are included. Matches (Full Codes).

<Effects According to the Present Invention>

6 is a graph for comparing the effects according to the first embodiment or the second embodiment with the effects according to the comparative example.

6 (a) shows the output codes of the ADC 130 for the bottom position B of the barrel 20 to the ceiling position T when the comparative embodiment shown in FIG. 2 is used. The horizontal axis of the graph represents the position of the barrel, and the vertical axis of the graph represents the output code of the ADC. The output code may have an integer value of 0 to 2 ⁿ -1.

In FIG. 6A, if the linear region is referred to as the first boundary position B + D1 to the second boundary position T-D2, the output code Code at the first boundary position B + D1 is shown. ) Value may be c, and the output code value at the second boundary position T-D2 may be 2 ^n- 1-d. That is, in the case of using the comparative embodiment, if you want to use only the section that guarantees linearity, it is not necessary to actually use the code section (0 ~ c) and the code section (2 ^n- 1-d ~ 2 ⁿ -1) waste Can be.

On the contrary, in FIG. 6B, when the first embodiment or the second embodiment shown in FIG. 4 or 5 is used, the second boundary position B + D1 to the second boundary of the barrel 20 are used. The output codes of the ADC 130 for the boundary position T-D2 are shown. The horizontal axis of the graph represents the position of the barrel, and the vertical axis of the graph represents the output code of the ADC. The output code may have an integer value of 0 to 2 ⁿ -1.

In FIG. 6B, the output code value at the first boundary position B + D1 is 0, and the output code value at the second boundary position T-D2 is 2. ⁿ -1. That is, in the case of using the first embodiment or the second embodiment, the ADC 130 may output all code values that can be output, even if only a section in which linearity is guaranteed.

In conclusion, in the case of using only the region where the linearity is guaranteed, according to an embodiment of the present invention, since the ADC 130 may provide more code values than the comparative embodiment, the resolution with respect to the lens position is increased. There is an advantage in that.

Modified Embodiments

7 is a configuration diagram of a VCM driving apparatus according to another embodiment of the present invention.

In FIG. 7, the order of the level shifting unit 115 and the amplifier 120 in the matched signal generation unit 12 is reversed as compared with that shown in FIG. 1.

FIG. 8 is a diagram for describing a method of matching a linear region in which linearity of a position change of a lens with respect to a change in current provided to a VCM is matched to an entire code range of an ADC according to a third embodiment of the present invention. The case of using the VCM driving apparatus 10 according to FIG. 7 is shown.

FIG. 9 is a diagram for describing a method of matching a linear region in which linearity of a position change of a lens with respect to a change in current provided to a VCM is matched to the entire code range output by the ADC according to the fourth embodiment of the present invention. As a case, the case where the VCM driving device 10 according to FIG. 7 is used is shown.

8 and 9, the amplifier 120 amplifies the differential signal Vdiff to generate a second amplified signal Vg2. The level shifting unit 115 shifts the second amplifying signal Vg2 to generate a matching signal Vs2. In FIG. 9, the differential signal Vdiff is amplified by a gain G ₂ = 8 α / (4 α-β ₂ -β ₁ ), and then shifted up by (2 α-β ₁ ) * G ₂ to obtain Vs ₂ .

At this time, the amplifier 120,

(1) a second value of the second value of the second amplified signal when the lens is in the second boundary position and a first value of the second amplified signal when the lens is in the first boundary position; The primary difference is,

(2) a second voltage which causes the ADC to output the largest output code among the allowable input voltages of the ADC when the lens is in the second boundary position, and the ADC when the lens is in the first boundary position A second difference value from the first voltage that causes the ADC to output the smallest output code among the allowable input voltages of

It may have an amplification factor to be equal to.

In this case, the level shifting unit 115 may be configured to apply a shift level that shifts the first value of the second amplified signal to be equal to the first voltage when the lens is in the first boundary position. have.

10 is a configuration diagram of a VCM driving apparatus according to another embodiment of the present invention.

Unlike FIG. 1 and FIG. 7, FIG. 10 is not provided as two blocks in which the functions of the level shifting unit 115 and the amplifier 120 included in the matching signal generation unit 12 can be distinguished from each other. It may be provided in one piece.

FIG. 11 shows the internal structure of the matching signal generation unit 12 of the VCM drive device 10 shown in FIG. The matched signal generator 12 may be referred to as an amplification-shift unit.

The matching signal generator 12 may include a first operational amplifier OP1, a second operational amplifier OP2, a third operational amplifier OP3, a first resistor R1, a second resistor R2, and a third resistor ( R3), a fourth resistor R4, a fifth resistor R5, an eighth resistor R8, and a ninth resistor RG.

In this case, a non-inverting signal (eg, V +) among the differential signals output from the hall sensor is input to the non-inverting input terminal of the first operational amplifier OP1, and the differential is input to the non-inverting input terminal of the second operational amplifier OP2. An inverted signal (eg, V−) may be input among the signals.

One end and the other end of the first resistor R1 may be connected to the output terminal O1 of the first operational amplifier OP1 and the inverting input terminal − of the third operational amplifier OP3, respectively.

One end and the other end of the second resistor R2 may be connected to the inverting input terminal (−) and the output terminal O3 of the third operational amplifier OP3, respectively.

In addition, one end and the other end of the third resistor R3 may be connected to the output terminal O2 of the second operational amplifier OP2 and the non-inverting input terminal (+) of the third operational amplifier OP3, respectively. have.

One end and the other end of the fourth resistor R4 may be connected to the non-inverting input terminal (+) and the shift up potential (Vshift) of the third operational amplifier OP3, respectively. The shift up potential Vshift may be a predetermined value.

In addition, one end and the other end of the fifth resistor R5 may be connected to an output terminal O1 of the first operational amplifier OP1 and an inverting input terminal − of the first operational amplifier OP1, respectively. .

In addition, one end and the other end of the eighth resistor R8 may be connected to the output terminal O2 of the second operational amplifier OP2 and the inverting input terminal − of the second operational amplifier OP2, respectively. .

In addition, one end and the other end of the ninth resistor RG may be connected to the inverting input terminal (-) of the first operational amplifier OP1 and the inverting input terminal of the second operational amplifier OP2, respectively. have.

At this time, the values of the first resistor R1 and the third resistor R3 are the same, and the values of the fifth resistor R5 and the eighth resistor R8 are the same, and the second resistor R2 and the second resistor R3 are the same. The values of the four resistors R4 may be the same.

At this time, according to the circuit analysis of the circuit shown in Figure 11, the output voltage (VOUT) of the matching signal generation unit 12 according to an embodiment of the present invention, (V +-V-) * (1 + 2R5 / RG) (R2 / R1) + Vshift.

[Equation 1]

VOUT = (V +-V-) * (1 + 2R5 / RG) (R2 / R1) + V _shift

= (V + _-V- ) * G ₃ + V _shift

In Equation 1, multiplication and addition operations exist one at a time. In this analysis, ([V +]-[V-]) of the Hall sensor's differential output voltage is first amplified by the gain G ₃ = (1 + 2R5 / RG) (R2 / R1) times. The amplified value is then _shifted by V _shift .

Compared with the circuit shown in FIG. 7, a relationship of G ₃ = (1 + 2R5 / RG) (R2 / R1) = G ₂ = 8 α / (4 α-β ₂ -β ₁ ) can be obtained and V _shift It can be understood that the relationship of (2 α-β ₁ ) * G ₂ is satisfied.

By using the embodiments of the present invention described above, those of ordinary skill in the art will be able to easily make various changes and modifications without departing from the essential characteristics of the present invention. The content of each claim in the claims may be combined in another claim without citations within the scope of the claims.

10: VCM drive
12: matching signal generator
20: barrel
110: Hall sensor
115: Level transition part
120: amplifier
130: ADC
145: output control unit
150: drive unit
B: floor position
B + D1: First boundary position
T: Ceiling location
T-D2: Second boundary position
Vdiff: differential signal
Vg, Vs2: Matched Signal
Vg2: second amplification signal
Vs: shift voltage

Claims (7)

A driving unit 150 for providing a driving current to the VCM for driving the lens that is to move from the bottom position of the barrel to the ceiling position;
A hall sensor 110 for outputting a differential signal representing a current position of the lens;
A matched signal generator 12 receiving the differential signal and generating a matched signal provided to an input terminal of the ADC;
The ADC (130) for converting the matched signal into a digital value; And
An output controller 145 for controlling the driver based on the digital value;
Including;
The matching signal has a first voltage such that the ADC outputs the smallest output code among the allowable input voltages of the ADC when the lens is in a first boundary position higher than the bottom position, and the lens is in the ceiling position. Has a second voltage which causes the ADC to output the largest output code among the allowable input voltages of the ADC when in the lower second boundary position,
The first boundary position and the second boundary position are different positions on the optical axis of the lens,
The matched signal generator includes a level shifter 115 for generating a shift voltage by shifting the differential signal, and an amplifier 120 for amplifying the shift voltage.
The level shifting unit is configured to shift the value of the differential signal by a predetermined value to generate the shift voltage.
The amplifier has a first difference value between a second value of the shift voltage when the lens is in the second boundary position and a first value of the shift voltage when the lens is in the first boundary position. Has an amplification factor such that the second difference value between the second voltage and the first voltage is equal to
VCM drive. The method of claim 1,
The output control unit is configured to control the lens to move in a linear region from the first boundary position to the second boundary position,
In the linear region, the change in the moving distance of the lens with respect to the change in the current provided to the VCM is constant, and in the region other than the linear region, the change in the moving distance of the lens with respect to the change in the current provided in the VCM is the lens. Inconsistent depending on the location of,
VCM drive. delete A driving unit 150 for providing a driving current to the VCM for driving the lens that is to move from the bottom position of the barrel to the ceiling position;
A hall sensor 110 for outputting a differential signal representing a current position of the lens;
A matched signal generator 12 receiving the differential signal and generating a matched signal provided to an input terminal of the ADC;
The ADC (130) for converting the matched signal into a digital value; And
An output controller 145 for controlling the driver based on the digital value;
Including;
The matching signal has a first voltage such that the ADC outputs the smallest output code among the allowable input voltages of the ADC when the lens is in a first boundary position higher than the bottom position, and the lens is in the ceiling position. Has a second voltage which causes the ADC to output the largest output code among the allowable input voltages of the ADC when in the lower second boundary position,
The first boundary position and the second boundary position are different positions on the optical axis of the lens,
The matched signal generator includes an amplifier 120 for amplifying the differential signal to generate a second amplified signal and a level shifter 115 for shifting the second amplified signal to generate the matched signal.
The amplifier is configured such that a second value of the second amplified signal when the lens is in the second boundary position and a first value of the second amplified signal when the lens is in the first boundary position. An amplification factor such that a first difference value is equal to a second difference value between the second voltage and the first voltage,
The level shifting section is adapted to apply a shift level that shifts the first value of the second amplified signal to be equal to the first voltage when the lens is in the first boundary position,
VCM drive. Hall sensor 110 for outputting a differential signal representing the current position of the lens to move from the bottom position of the barrel to the ceiling position;
A matched signal generator 12 receiving the differential signal and generating a matched signal provided to an input terminal of the ADC; And
The ADC 130 for converting the matching signal into a digital value
As comprising, VCM drive device,
The matching signal has a first voltage such that the ADC outputs the smallest output code among the allowable input voltages of the ADC when the lens is in a first boundary position higher than the bottom position, and the lens is in the ceiling position. Has a second voltage which causes the ADC to output the largest output code among the allowable input voltages of the ADC when in the lower second boundary position,
The first boundary position and the second boundary position are different positions on the optical axis of the lens,
The matched signal generator includes a level shifter 115 for generating a shift voltage by shifting the differential signal, and an amplifier 120 for amplifying the shift voltage.
The level shifting unit is configured to shift the value of the differential signal by a predetermined value to generate the shift voltage.
The amplifier has a first difference value between a second value of the shift voltage when the lens is in the second boundary position and a first value of the shift voltage when the lens is in the first boundary position. Has an amplification factor such that the second difference value between the second voltage and the first voltage is equal to
VCM drive. Lens module for a user device comprising the VCM driving device of claim 5. A user device comprising the lens module for user device of claim 6.

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