Apparatus for controlling a lens module and reducing offset of a hall sensor

Abstract

An apparatus configured to reduce offset of a Hall sensor includes a voltage-to-current conversion circuit and a current mirror circuit. The voltage-to-current conversion circuit is configured to generate a current configured to decrease when a voltage of an input terminal of the Hall sensor input with a bias current increases and to increase when the voltage of the input terminal of the Hall sensor input with the bias current decreases. The current mirror circuit has a current mirror structure configured to feedback the bias current based on the current generated by the voltage-to-current conversion circuit.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0103263, filed on August 18, 2020, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] This disclosure relates to means for controlling a lens module and reducing the offset of a Hall sensor. Background Technology

[0004] Typically, when a lens module moves based on a force received from an external source, techniques are widely used to fix its position relative to the outside of the lens module.

[0005] For example, a camera module may include an optical image stabilizer that fixes the position of a lens module therein, even when the camera module is subjected to external forces.

[0006] Hall effect sensors can be used to measure the position of a lens module, and they can output a voltage that varies depending on the position of the lens module. As the accuracy of the correlation between the Hall effect sensor's output voltage and the lens module's position increases, the accuracy of optical image stabilization can be significantly improved.

[0007] The output voltage of a Hall sensor can vary slightly depending on external factors such as temperature, and the variation in output voltage caused by external factors can reduce the accuracy of the correspondence between the output voltage of the Hall sensor and the position information of the lens module. Summary of the Invention

[0008] The summary portion of this invention is intended to provide a brief overview of the chosen inventive concepts, which will be further described in the detailed description portion below. This summary portion is not intended to identify key or essential features of the claimed subject matter, nor to help determine the scope of the claimed subject matter.

[0009] In one general aspect, the device configured to reduce the offset of the Hall sensor includes a voltage-to-current conversion circuit and a current mirror circuit. The voltage-to-current conversion circuit is configured to generate a current that decreases when the voltage at the input terminal of the Hall sensor, which is being biased by the input current, increases, and increases when the voltage at the input terminal decreases. The current mirror circuit has a current mirror structure configured to provide feedback bias current based on the current generated by the voltage-to-current conversion circuit.

[0010] The current mirror circuit can include a feedback input transistor configured to cause the current generated by the voltage-to-current conversion circuit to flow between a source terminal and a drain terminal of the feedback input transistor, and a feedback output transistor configured to cause the bias current to flow between a source terminal and a drain terminal of the feedback output transistor. The current mirror circuit can be configured to mirror the current generated by the voltage-to-current conversion circuit through a gate terminal of the feedback input transistor and a gate terminal of the feedback output transistor.

[0011] The voltage-to-current conversion circuit can include a conversion transistor configured to cause the current generated by the voltage-to-current conversion circuit to flow between a drain terminal and a source terminal of the conversion transistor. The current mirror circuit can further include a feedback resistor connected between the feedback input transistor and the conversion transistor.

[0012] The feedback input transistor can include a first feedback input transistor and a second feedback input transistor connected in series with each other. The feedback output transistor can include a first feedback output transistor and a second feedback output transistor connected in series with each other. The first feedback input transistor and the second feedback input transistor can mirror the current generated by the voltage-to-current conversion circuit in parallel to the first feedback output transistor and the second feedback output transistor.

[0013] The feedback resistor can be connected between a gate terminal of the first feedback input transistor and a gate terminal of the second feedback input transistor.

[0014] The voltage-to-current conversion circuit can further include a conversion resistor connected between the conversion transistor and the ground.

[0015] The apparatus can further include a conversion operational amplifier having an output terminal connected to a gate terminal of the conversion transistor, one of a plurality of input terminals of the conversion operational amplifier receiving a voltage corresponding to the voltage of the input terminal of the Hall sensor, and another of the plurality of input terminals of the conversion operational amplifier receiving a voltage corresponding to a voltage at a node between the conversion transistor and the conversion resistor.

[0016] The voltage-to-current conversion circuit can further include a buffer configured to invert the voltage of the input terminal of the Hall sensor and output a voltage corresponding to the voltage of the input terminal of the Hall sensor to the conversion operational amplifier.

[0017] The voltage-current conversion circuit can include a conversion transistor configured to cause a current generated by the voltage-current conversion circuit to flow between a drain terminal and a source terminal of the conversion transistor, and a buffer configured to invert a voltage of an input terminal of the Hall sensor and output a voltage corresponding to the voltage of the input terminal of the Hall sensor. The conversion transistor can be configured to generate a current configured to increase when the voltage output from the buffer increases and decrease when the voltage output from the buffer decreases.

[0018] The buffer can include a buffer operational amplifier, a first resistor connected between one of a plurality of input terminals of the buffer operational amplifier and the input terminal of the Hall sensor, a second resistor connected between the one of the plurality of input terminals of the buffer operational amplifier and an output terminal of the buffer operational amplifier, and a third resistor and a fourth resistor connected to another of the plurality of input terminals of the buffer operational amplifier.

[0019] The buffer can be configured to apply a reference voltage different from a ground voltage to the third resistor and the fourth resistor.

[0020] In another general aspect, an apparatus configured to control a lens module includes a Hall sensor, an analog-to-digital (AD) converter, a driver, a voltage-current conversion circuit, and a current mirror circuit. The Hall sensor is configured to pass a magnetic flux based on movement of the lens module. The AD converter is configured to output a digital value based on a voltage difference between a first output terminal and a second output terminal of the Hall sensor. The driver is configured to generate a driving signal based on the digital value to control the movement of the lens module. The voltage-current conversion circuit is configured to generate a current configured to decrease when a voltage of an input terminal of the Hall sensor to which a bias current is input increases, and increase when the voltage of the input terminal decreases. The current mirror circuit has a current mirror structure configured to feedback the bias current based on the current generated by the voltage-current conversion circuit.

[0021] The voltage-current conversion circuit can include a conversion transistor configured to cause a current generated by the voltage-current conversion circuit to flow between a drain terminal and a source terminal of the conversion transistor. The current mirror circuit can include a feedback resistor configured to cause the current generated by the voltage-current conversion circuit to flow.

[0022] The current mirror circuit can include first and second feedback input transistors, and first and second feedback output transistors. The first and second feedback input transistors can each be configured to cause a current generated by the voltage-to-current conversion circuit to flow between a source terminal and a drain terminal of the first feedback input transistor and between a source terminal and a drain terminal of the second feedback input transistor, respectively, and the first and second feedback input transistors are connected in series with each other. The first and second feedback output transistors can each be configured to cause a bias current to flow between a source terminal and a drain terminal of the first feedback output transistor and between a source terminal and a drain terminal of the second feedback output transistor, respectively, and the first and second feedback output transistors are connected in series with each other. A feedback resistor can be connected between a gate terminal of the first feedback input transistor and a gate terminal of the second feedback input transistor.

[0023] The voltage-to-current conversion circuit can further include a buffer configured to invert a voltage of an input terminal of the Hall sensor and output a voltage corresponding to the voltage of the input terminal of the Hall sensor, and a conversion resistor connected between the conversion transistor and the ground. The conversion transistor can be configured to generate a current configured to increase as the voltage output from the buffer increases and decrease as the voltage output from the buffer decreases.

[0024] The apparatus can further include an amplifier configured to amplify a voltage difference between the first and second output terminals of the Hall sensor. The AD converter can be configured to output a digital value based on an output voltage of the amplifier.

[0025] Other features and aspects will become apparent from the following detailed description, drawings and claims. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1A and Figure 1B is a diagram illustrating an example of an apparatus for reducing an offset of a Hall sensor.

[0027] Figure 2A and Figure 2B is a diagram illustrating an example of a modified structure of a current mirror circuit of an apparatus for reducing an offset of a Hall sensor.

[0028] Figure 3 and Figure 4 is a diagram illustrating an example of an apparatus for reducing an offset of a Hall sensor and an apparatus for controlling a lens module.

[0029] Figure 5is a graph showing an example of a main voltage / current of an apparatus for reducing offset of a Hall sensor and an apparatus for controlling a lens module.

[0030] Throughout the drawings and specific embodiments, identical reference numerals designate identical elements throughout the several views. The drawings can not be to scale and the relative dimensions, proportions and depiction of elements in the drawings can be exaggerated for purpose of clarity, illustration and convenience. DETAILED DESCRIPTION

[0031] The following detailed description is presented to aid in understanding the method, apparatus and / or system described in this application. Various changes, modifications and equivalents can be used and will be apparent to those skilled in the art once the disclosure in this application is understood. For example, the order of the operations described in this application can be altered where appropriate, and the sequence can be changed without departing from the scope of the application, which is to be given the full breadth of the appended claims. Also, the description of features in this application can be omitted for the sake of clarity and brevity.

[0032] The features described in this application can be implemented in different forms and should not be construed as limited to the examples described in this application. Rather, these examples are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the methods, apparatus and / or systems described in this application to others skilled in the art. Moreover, the examples described in this application are not intended to limit the scope of the methods, apparatus and / or systems described in this application to the exact details shown and described, nor does it exclude modifications and changes within the abilities of those skilled in the art.

[0033] Throughout this specification, it is to be understood that when an element such as a layer, region or sheet (substrate) is referred to as being "on" or "connected to" or "coupled to" another element, it can be directly on, directly connected to, or directly coupled to the other element or one or more intervening elements can be present. In contrast, when an element such as a layer, region or sheet (substrate) is referred to as being "directly on", "directly connected to", or "directly coupled to" another element, then there are no intervening elements present. Like reference numerals refer to like elements throughout the specification. As used in this application, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] Although the terms such as "first", "second", and "third" can be used in this application to describe various components, parts, regions, layers or sections, these components, parts, regions, layers or sections are not limited by the terms. Rather, the terms are merely used to distinguish one component, part, region, layer or section from another component, part, region, layer or section. Thus, a first component, a first part, a first region, a first layer or a first section mentioned in the examples can also be called a second component, a second part, a second region, a second layer or a second section without departing from the teachings of the examples described in this application.

[0035] Spatial relative terms, such as "on", "upper", "lower", "below", and "above", can be used herein for ease of description to describe the relationships or positional orientations in the drawings. It will be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the drawings. For example, if the device in the drawings is turned over, elements described as being "on" or "upper" other elements would then be oriented "below" or "lower" relative to the other element. Thus, the term "on" can encompass both an "on" and "under" orientation depending on the specific orientation in the drawings. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0036] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in this application, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, components, elements, and / or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, elements, and / or groups thereof.

[0037] The features of the examples described in this application can be combined in a variety of ways as will be apparent after the disclosure of this application is understood. In addition, although the examples described in this application have a variety of configurations, other configurations are possible in light of the disclosure of this application.

[0038] Figure 1A and Figure 1B are diagrams showing examples of an apparatus for reducing offset of a Hall sensor.

[0039] Referring to Figure 1A, the Hall sensor 300 can receive a bias current I HALL1 Through the bias current I HALL1 of the Hall sensor 300 can flow to the ground through the ground terminal 302 of the Hall sensor 300.

[0040] The Hall sensor 300 can sense a magnetic flux passing through the Hall sensor 300 by using the Hall effect. When the magnetic flux passes through the Hall sensor 300, the Hall sensor 300 can generate a bias current I HALL1 and a Hall voltage in a direction perpendicular to the magnetic flux, and a voltage difference between a first output voltage of the first output terminal 303 and a second output voltage of the second output terminal 304 can correspond to the Hall voltage. Accordingly, the voltage difference between the first output terminal 303 and the second output terminal 304 can be used as a measurement value of the magnetic flux passing through the Hall sensor 300. In the present application, it should be noted that the use of the expression "may" with respect to examples or embodiments, for example, as to what can be included or implemented with respect to examples or embodiments, means that there is at least one example or embodiment in which such a feature is included or implemented, and all examples and embodiments are not limited thereto.

[0041] An equivalent circuit of the Hall sensor 300 can be composed of a plurality of resistors. Resistance values of the plurality of resistors can vary due to external factors of the Hall sensor 300, such as temperature.

[0042] For example, when the resistance values of the plurality of resistors increase, the voltage of each of the first output terminal 303 and the second output terminal 304 can increase together, and when the resistance values of the plurality of resistors decrease, the voltage of each of the first output terminal 303 and the second output terminal 304 can decrease together.

[0043] A common voltage variation value of the first output terminal 303 and the second output terminal 304 according to external factors of the Hall sensor 300, for example, temperature, can be defined as an offset of the Hall sensor 300.

[0044] Since the voltage difference between the first output terminal 303 and the second output terminal 304 can be proportional to the voltage of the first output terminal 303 and the second output terminal 304 compared to a unit magnetic flux passing through the Hall sensor 300, the offset of the Hall sensor 300 can affect the voltage difference between the first output terminal 303 and the second output terminal 304 compared to a unit magnetic flux passing through the Hall sensor 300.

[0045] That is, the voltage difference between the first output terminal 303 and the second output terminal 304 compared to a unit magnetic flux passing through the Hall sensor 300 can vary according to the magnetic flux passing through the Hall sensor 300 and the offset of the Hall sensor 300.

[0046] Accordingly, from the viewpoint of extracting the magnetic flux information passing through the Hall sensor 300 from the voltage difference between the first output terminal 303 and the second output terminal 304, the influence of the offset can be determined as a part of the magnetic flux information passing through the Hall sensor 300, and the accuracy of the extracted magnetic flux information can be reduced.

[0047] The apparatus 100a for reducing an offset of a Hall sensor according to one or more embodiments of the disclosure can reduce the offset of the Hall sensor 300. For example, the apparatus 100a for reducing an offset of a Hall sensor can be implemented as an integrated circuit (IC), can be mounted on a substrate such as a printed circuit board, and can be electrically connected to the Hall sensor 300 through the substrate.

[0048] Referring to Figure 1A , the apparatus 100a for reducing an offset of a Hall sensor according to one or more embodiments of the disclosure can include a voltage-to-current conversion circuit 110 and a current mirror circuit 120a.

[0049] The voltage-to-current conversion circuit 110 can be configured to generate a current I HALL2 as the voltage VTOP of the input terminal 301 (the bias current I HALL1 increases. HALL2 decreases, and as the voltage VTOP of the input terminal 301 decreases, the current I HALL2 increases.

[0050] The current mirror circuit 120a can be configured to feed back the bias current I HALL2 generated by the voltage-to-current conversion circuit 110 based on the current I HALL1 generated by the voltage-to-current conversion circuit 110.

[0051] Accordingly, the bias current I HALL1 of the Hall sensor 300 can decrease as the voltage VTOP of the input terminal 301 increases, and can increase as the voltage VTOP of the input terminal 301 decreases.

[0052] That is, the voltage VTOP of the input terminal 301 can increase as the resistance value of the Hall sensor 300 increases, and the voltage VTOP of the input terminal 301 can increase as the bias current I HALL1 decreases. The voltage VTOP of the input terminal 301 can decrease as the resistance value of the Hall sensor 300 decreases, and the voltage VTOP of the input terminal 301 can decrease as the bias current I HALL1 increases.

[0053] The apparatus 100a for reducing offset of a Hall sensor according to one or more embodiments of the present disclosure can have a structure in which the start and end of the process of reducing the offset of the Hall sensor 300 are the bias current I HALL1 or the input terminal 301, and thus the efficiency, accuracy, and stability of the process can be improved as a whole.

[0054] The current mirror circuit 120a can include feedback input transistors M4 and M5 configured such that the current I HALL2 generated by the voltage-to-current conversion circuit 110 flows between the source terminal and the drain terminal, and can include feedback output transistors M2 and M3 configured such that the bias current I HALL1 flows between the source terminal and the drain terminal.

[0055] The current mirror circuit 120a can mirror the gate terminals of the feedback input transistors M4 and M5 and the gate terminals of the feedback output transistors M2 and M3. For example, the voltage of the gate terminals of the feedback input transistors M4 and M5 and the voltage of the gate terminals of the feedback output transistors M2 and M3 can be shared with each other, and the gate terminals of the feedback input transistors M4 and M5 can be electrically connected to the drain terminals of the feedback input transistors M4 and M5.

[0056] Thus, the magnitude of the bias current I HALL1 may be determined to be proportional to the current I HALL2 generated by the voltage-to-current conversion circuit 110 at a preset ratio (e.g., a one-to-one (1:1) ratio). Here, the preset ratio can be determined based on the W / L of the feedback input transistors M4 and M5 and the W / L of the feedback output transistors M2 and M3.

[0057] In addition, since the effects of external factors (e.g., temperature) on the feedback input transistors M4 and M5 and the effects of external factors on the feedback output transistors M2 and M3 can be the same as each other, the ratio (e.g., 1 to 1) between the current I HALL2 generated by the voltage-to-current conversion circuit 110 and the bias current I HALL1 may be substantially unaffected by external factors.

[0058] Thus, the apparatus 100a for reducing offset of a Hall sensor according to one or more embodiments of the present disclosure can more stably reduce the offset of the Hall sensor 300.

[0059] For example, the feedback input transistors M4 and M5 can include a first feedback input transistor M5 and a second feedback input transistor M4 connected in series to each other. For example, the feedback output transistors M2 and M3 can include a first feedback output transistor M2 and a second feedback output transistor M3 connected in series to each other.

[0060] The first feedback input transistor M5 and the second feedback input transistor M4 can be mirrored in parallel with the first feedback output transistor M2 and the second feedback output transistor M3. That is, a voltage of a gate terminal of the first feedback input transistor M5 and a voltage of a gate terminal of the first feedback output transistor M2 can be shared with each other, and a voltage of a gate terminal of the second feedback input transistor M4 and a voltage of a gate terminal of the second feedback output transistor M3 can be shared with each other, but the voltage of the gate terminal of the first feedback input transistor M5 and the voltage of the gate terminal of the second feedback output transistor M3 can be separated from each other, and the voltage of the gate terminal of the second feedback input transistor M4 and the voltage of the gate terminal of the first feedback output transistor M2 can be separated from each other.

[0061] Accordingly, the current mirror circuit 120a can more stably mirror the current I HALL2 generated by the voltage-current conversion circuit 110. HALL1 And can further expand the range of the offset of the Hall sensor 300 which can be reduced.

[0062] The current mirror circuit 120a can be provided such that the current I HALL2 generated by the voltage-current conversion circuit 110 flows, and can further include a feedback resistor R6 electrically connected between a gate terminal of the first feedback input transistor M5 and a gate terminal of the second feedback input transistor M4.

[0063] That is, the feedback resistor R6 can form a bias voltage of a path through which the current I HALL2 generated by the voltage-current conversion circuit 110 flows, and can further form a difference voltage between the voltage of the gate terminal of the first feedback input transistor M5 and the voltage of the gate terminal of the second feedback input transistor M4.

[0064] The feedback resistor R6 can be electrically connected between the feedback input transistors M4 and M5 and the conversion transistor M1, and can form a bias voltage of a path through which the current I HALL2 generated by the voltage-current conversion circuit 110 flows.

[0065] The voltage-current conversion circuit 110 can include a buffer 111 and a conversion core circuit 112, and the conversion core circuit 112 can include at least one of a conversion transistor M1, a conversion resistor R5, and a conversion operational amplifier OP2.

[0066] The conversion transistor M1 can be configured such that the current I HALL2 flows between the drain terminal and the source terminal.

[0067] Since the conversion transistor M1 can generate the current I HALL2 based on the voltage of the gate terminal, the voltage-current conversion operation can be performed.

[0068] The conversion resistor R5 can be electrically connected between the conversion transistor M1 and the ground. Therefore, the stability of the bias voltage of the conversion transistor M1 can be improved.

[0069] The conversion operational amplifier OP2 can have a structure in which the output terminal is electrically connected to the gate terminal of the conversion transistor M1, the voltage corresponding to the voltage VTOP of the input terminal 301 of the Hall sensor is input to one of the plurality of input terminals, and a node between the conversion transistor M1 and the conversion resistor R5 is electrically connected to another of the plurality of input terminals. Therefore, the voltage-current conversion circuit 110 can more stably perform the voltage-current conversion operation.

[0070] For example, when the positive input voltage VP of the conversion operational amplifier OP2 increases, the voltage of the gate terminal of the conversion transistor M1 can increase, and the current between the drain terminal and the source terminal of the conversion transistor M1 can increase, and the negative input voltage VN of the conversion operational amplifier OP2 can increase as the current flowing through the conversion resistor R5 increases.

[0071] For example, when the positive input voltage VP of the conversion operational amplifier OP2 decreases, the voltage of the gate terminal of the conversion transistor M1 can decrease, and the current between the drain terminal and the source terminal of the conversion transistor M1 can decrease, and the negative input voltage VN of the conversion operational amplifier OP2 can decrease as the current flowing through the conversion resistor R5 decreases.

[0072] That is, the conversion transistor M1 can generate the current I HALL2 that increases when the voltage output from the buffer 111 increases, and that decreases when the voltage output from the buffer 111 decreases. HALL2 HALL2

[0073] The buffer 111 can invert the voltage VTOP of the input terminal 301 of the Hall sensor 300 and output the positive input voltage VP corresponding to the voltage VTOP to the conversion operational amplifier OP2.

[0074] ​​Since the input impedance of the buffer 111 can be higher than the output impedance of the buffer 111, the influence of the voltage-current conversion circuit 110 on the voltage VTOP can be reduced.

[0075] For example, the buffer 111 can include at least one of a buffer operational amplifier OP1, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

[0076] The first resistor R1 can be electrically connected between one of the plurality of input terminals of the buffer operational amplifier OP1 and the input terminal 301 of the Hall sensor 300.

[0077] The second resistor R2 can be electrically connected between one of the plurality of input terminals of the buffer operational amplifier OP1 and the output terminal of the buffer operational amplifier OP1.

[0078] The third resistor R3 and the fourth resistor R4 can be electrically connected to the other of the plurality of input terminals of the buffer operational amplifier OP1.

[0079] That is, since the buffer 111 can have an inverting amplifier structure, the voltage VTOP of the input terminal 301 of the Hall sensor 300 can be inverted, and the voltage VTOP of the input terminal 301 can be amplified with a gain based on a relationship between the resistance values of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4.

[0080] For example, the buffer 111 can be configured to apply a reference voltage VREF different from a ground voltage to the third resistor R3 and the fourth resistor R4. Accordingly, the positive input voltage VP of the conversion operational amplifier OP2 can be easily set, and the current I HALL2 of the conversion transistor M1 can be easily adjusted, for example, according to control of the reference voltage VREF. The switching of the conversion transistor M1 can be controlled, and the switching of the device 100a for reducing the offset of the Hall sensor according to one or more embodiments of the disclosure can be controlled, for example.

[0081] Referring to Figure 1B When the voltage VTOP of the input terminal 301 of the Hall sensor 300 increases / decreases, the positive input voltage VP of the conversion operational amplifier OP2 can decrease / increase, the current I HALL2 of the conversion transistor M1 can decrease / increase, the current I HALL1 of the feedback input transistors M4 and M5 can decrease / increase, and the current I HALL1 of the feedback output transistors M2 and M3 can decrease / increase.

[0082] That is, the bias current I HALL1decreases as the voltage VTOP of the input terminal 301 increases, and can increase as the voltage VTOP of the input terminal 301 decreases.

[0083] Figure 2A and Figure 2B is a diagram showing an example of a modified structure of a current mirror circuit of an apparatus for reducing offset of a Hall sensor.

[0084] Referring to Figure 2A , the feedback input transistor M5 and the feedback output transistor M2 of the current mirror circuit 120b of the apparatus 100b for reducing offset of a Hall sensor according to one or more embodiments of the disclosure can each be one. Here, Figure 1A the feedback resistor shown in FIG. 1A can be omitted. The number of the feedback input transistor M5 and the feedback output transistor M2 can be determined based on the threshold voltage of the feedback input transistor M5 and the feedback output transistor M2 and the power source VDD.

[0085] Referring to Figure 2B , the current mirror circuit 120c of the apparatus 100c for reducing offset of a Hall sensor according to one or more embodiments of the disclosure can be implemented as an NMOS, and it can be of a different type from the PMOS of the current mirror circuit shown in FIG. 1B. Figure 1A

[0086] Figure 3 and Figure 4 is a diagram showing an example of an apparatus for reducing offset of a Hall sensor and an apparatus for controlling a lens module.

[0087] Referring to Figure 3 , the apparatus 100d for controlling a lens module according to one or more embodiments of the disclosure can include Figure 1A the apparatus for reducing offset of a Hall sensor shown in FIG. 1A, and can include at least one of a first current source 151 and a second current source 152.

[0088] The first current source 151 and the second current source 152 can each generate a bias current I HALL1 and a current I HALL2 of the feedback input transistors M4 and M5. For example, the first current source 151 and the second current source 152 can receive a first control signal and a second control signal (control 1 and control 2), and can generate a bias current I HALL1 and a current I HALL2 , where the amplitude of the bias current I HALL1 and the current I HALL2 is determined based on the first control signal and the second control signal (control 1 and control 2).

[0089] Referring to Figure 3 ​At least one of the Hall sensor 300, the amplifier 130, the analog-to-digital (AD) converter 140, and the driver can be included in the apparatus 100d for controlling the lens module.

[0090] The amplifier 130 can amplify a voltage difference between the first output terminal 303 and the second output terminal 304 of the Hall sensor 300. For example, the amplifier 130 can be implemented as a (non-)inverting amplifier circuit in which an operational amplifier and a plurality of resistors are combined, and can generate a voltage amplified in proportion to the voltage difference between the first output terminal 303 and the second output terminal 304.

[0091] The gain of the amplifier 130 can be determined according to a relationship between resistance values of the plurality of resistors. When a wide magnetic flux sensing range of the Hall sensor 300 is required, the amplifier 130 with a low gain can be advantageous, and when a high magnetic flux sensing resolution of the Hall sensor 300 is required, the amplifier 130 with a high gain can be advantageous.

[0092] The AD converter 140 can output a digital value based on an analog value corresponding to the voltage difference between the first output terminal 303 and the second output terminal 304 of the Hall sensor 300 or the output voltage of the amplifier 130.

[0093] The driver can generate a driving signal to control the movement of the lens module based on the digital value output from the AD converter 140.

[0094] Referring to Figure 4 The apparatus 100e for controlling the lens module according to one or more embodiments of the disclosure can include a device for reducing the offset of the Hall sensor, and can be electrically connected to the Hall sensor 300.

[0095] The Hall sensor 300 can be disposed such that the magnetic flux based on the movement of the lens module 210 passes therethrough.

[0096] The driver 220 can receive an output value of the apparatus 100e for controlling the lens module corresponding to the magnetic flux information passing through the Hall sensor 300, and can generate position information of the lens module 210 through the magnetic flux information.

[0097] For example, the driver 220 can be included in the apparatus 100e for controlling the lens module, or can be implemented as a separate integrated circuit of the apparatus 100e for controlling the lens module.

[0098] The driver 220 can include an optical image stabilization (OIS) control structure, can determine the amplitude of the driving current based on the magnetic flux information, and output a driving signal including the determined driving current to the driving coil 230.

[0099] The drive coil 230 can generate a magnetic flux based on a drive current included in a drive signal, and can be disposed near the magnetic member 211 of the lens module 210. For example, the drive coil 230 and the Hall sensor 300 can be disposed on the first substrate 240.

[0100] The lens module 210 can move according to a force received by the magnetic member 211 in response to the magnetic flux of the drive coil 230. In this case, the lens module 210 can move to change the magnetic flux in a direction opposite to a change in the magnetic flux through the Hall sensor 300. Accordingly, the absolute position of the lens module 210 can be substantially fixed, and an image obtained by the lens module 210 can be stable.

[0101] Meanwhile, the processor 270 can be implemented as an image signal processor (ISP), receive image information from the image sensor 262 on the first support member 261, and transmit processed information to the driver 220.

[0102] The lens module 210 can move one-dimensionally or two-dimensionally according to rotation of the plurality of guide balls 212 on the second support member 213, and can be surrounded by the housing 250.

[0103] A structure including the lens module, a peripheral part of the lens module 210, and most of the housing 250 can be defined as a camera module.

[0104] Figure 5 is a graph showing an example of a main voltage / current of an apparatus for reducing offset of a Hall sensor and an apparatus for controlling a lens module.

[0105] Referring to Figure 5 , a resistance value R HALL of the Hall sensor can be set to gradually increase from 900 ohms to 1100 ohms in a time of 1 ms. That is, the resistance value R HALL of the Hall sensor can be set to increase from 90% of 1000 ohms to 110% of 1000 ohms.

[0106] As the resistance value R HALL increases, a voltage VTOP of an input terminal of the Hall sensor can increase, and a positive input voltage VP and a negative input voltage VN of a conversion operational amplifier can decrease, and a current I HALL2 of a feedback input transistor can decrease, and a current I HALL1 of a feedback output transistor can decrease.

[0107] When the resistance value R HALLWhen 90% of 1000 ohms, the voltage VTOP of the input terminal of the Hall sensor can be a voltage of about 99.47% of 1V, and when the resistance value R of the Hall sensor is 110% of 1000 ohms HALL When 110% of 1000 ohms, the voltage VTOP of the input terminal of the Hall sensor can be a voltage of about 100.43% of 1V.

[0108] In other words, the change in the voltage VTOP of the input terminal of the Hall sensor can be very small compared to the change in the resistance value R of the Hall sensor HALL , and the change in the voltage VTOP of the input terminal of the Hall sensor can correspond to the offset of the Hall sensor, so that the apparatus for reducing the offset of the Hall sensor and the apparatus for controlling the lens module according to one or more embodiments of the disclosure can effectively reduce the offset of the Hall sensor.

[0109] As described above, according to one or more embodiments of the disclosure, since the apparatus for reducing the offset of the Hall sensor and the apparatus for controlling the lens module can have a structure in which the start and end of the process of reducing the offset of the Hall sensor are biased currents, it is possible to improve the efficiency, accuracy, and stability of the process as a whole.

[0110] Since the apparatus for reducing the offset of the Hall sensor and the apparatus for controlling the lens module can reduce the offset without an external element (e.g., temperature) sensing structure (e.g., a temperature sensor, a Hall sensor to be compared), it can be easier to simplify / miniaturize.

[0111] While the disclosure includes specific examples, it will be apparent after understanding the disclosure of the present application that various changes in the form and details can be made without departing from the spirit and scope of the claims and their equivalents. The examples described in the present application should be understood only in a descriptive sense and not for limiting purposes. The description of features or aspects in each example should be understood to be applicable to similar features or aspects in other examples. If the described techniques are performed in a different order, and / or if the components in the described systems, architectures, devices, or circuits are combined and / or replaced with other components or their equivalents or supplemented with additional components, appropriate results can still be achieved. Therefore, the scope of the disclosure is not limited by the specific embodiments, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included in the disclosure.

Claims

1. An apparatus configured to reduce offset of a Hall sensor, comprising: a voltage-to-current conversion circuit configured to generate a current configured to decrease when a voltage of an input terminal of the Hall sensor to which a bias current is input increases and to increase when the voltage of the input terminal decreases; and a current mirror circuit having a current mirror structure configured to feed back the bias current based on the current generated by the voltage-to-current conversion circuit, wherein the voltage-to-current conversion circuit comprises: a conversion transistor configured to cause the current generated by the voltage-to-current conversion circuit to flow between a drain terminal and a source terminal of the conversion transistor; a conversion resistor connected between the conversion transistor and a ground; and a conversion operational amplifier having an output terminal connected to a gate terminal of the conversion transistor, receiving a voltage corresponding to the voltage of the input terminal of the Hall sensor to one of a plurality of input terminals of the conversion operational amplifier, and receiving a voltage corresponding to a voltage at a node between the conversion transistor and the conversion resistor to another of the plurality of input terminals of the conversion operational amplifier.

2. The apparatus of claim 1, wherein, the current mirror circuit comprises: a feedback input transistor configured to cause the current generated by the voltage-to-current conversion circuit to flow between a source terminal and a drain terminal of the feedback input transistor, and a feedback output transistor configured to cause the bias current to flow between a source terminal and a drain terminal of the feedback output transistor, and wherein the current mirror circuit is configured to mirror the current generated by the voltage-to-current conversion circuit through a gate terminal of the feedback input transistor and a gate terminal of the feedback output transistor.

3. The apparatus of claim 2, wherein, the current mirror circuit further comprises a feedback resistor connected between the feedback input transistor and the conversion transistor.

4. The apparatus of claim 3, wherein, the feedback input transistor comprises a first feedback input transistor and a second feedback input transistor connected in series to each other, the feedback output transistor comprises a first feedback output transistor and a second feedback output transistor connected in series to each other, and the first feedback input transistor and the second feedback input transistor mirror the current generated by the voltage-to-current conversion circuit in parallel to the first feedback output transistor and the second feedback output transistor.

5. The apparatus of claim 4, wherein, the feedback resistor is connected between a gate terminal of the first feedback input transistor and a gate terminal of the second feedback input transistor.

6. The apparatus of claim 1, wherein, the voltage-to-current conversion circuit further comprises a buffer configured to invert the voltage of the input terminal of the Hall sensor and output a voltage corresponding to the voltage of the input terminal of the Hall sensor to the conversion operational amplifier.

7. The apparatus of claim 1, wherein, the voltage-to-current conversion circuit comprises: a buffer configured to invert the voltage of the input terminal of the Hall sensor and output a voltage corresponding to the voltage of the input terminal of the Hall sensor, and wherein the conversion transistor is configured to generate a current configured to increase when the voltage output from the buffer increases and to decrease when the voltage output from the buffer decreases.

8. The apparatus of claim 7, wherein, The buffer includes: a buffer operational amplifier; a first resistor connected between one of a plurality of input terminals of the buffer operational amplifier and the input terminal of the Hall sensor; a second resistor connected between the one of the plurality of input terminals of the buffer operational amplifier and an output terminal of the buffer operational amplifier; and a third resistor and a fourth resistor connected to another of the plurality of input terminals of the buffer operational amplifier.

9. The apparatus of claim 8, wherein, The buffer is configured to apply a reference voltage different from a ground voltage to the third resistor and the fourth resistor.

10. An apparatus configured to control a lens module, comprising: a Hall sensor configured to pass a magnetic flux based on movement of the lens module; an analog-to-digital converter configured to output a digital value based on a voltage difference between a first output terminal of the Hall sensor and a second output terminal of the Hall sensor; a driver configured to generate a driving signal based on the digital value to control the movement of the lens module; a voltage-to-current conversion circuit configured to generate a current configured to decrease when a voltage of an input terminal of the Hall sensor to which a bias current is input increases and to increase when the voltage of the input terminal decreases; and a current mirror circuit having a current mirror structure configured to feedback the bias current based on the current generated by the voltage-to-current conversion circuit, wherein the voltage-to-current conversion circuit includes: a conversion transistor configured to cause the current generated by the voltage-to-current conversion circuit to flow between a drain terminal and a source terminal of the conversion transistor; a conversion resistor connected between the conversion transistor and a ground; and a conversion operational amplifier having an output terminal connected to a gate terminal of the conversion transistor, receiving a voltage corresponding to the voltage of the input terminal of the Hall sensor to one of a plurality of input terminals of the conversion operational amplifier, and receiving a voltage corresponding to a voltage at a node between the conversion transistor and the conversion resistor to another of the plurality of input terminals of the conversion operational amplifier.

11. The apparatus of claim 10, wherein, The voltage-to-current conversion circuit includes: wherein the current mirror circuit includes a feedback resistor configured to cause the current generated by the voltage-to-current conversion circuit to flow.

12. The apparatus of claim 11, wherein, The current mirror circuit includes: a first feedback input transistor and a second feedback input transistor each configured to cause the current generated by the voltage-to-current conversion circuit to flow between a source terminal and a drain terminal of the first feedback input transistor and between a source terminal and a drain terminal of the second feedback input transistor, respectively, and the first feedback input transistor and the second feedback input transistor are connected in series to each other; and a first feedback input transistor and a second feedback input transistor each configured to cause the current generated by the voltage-to-current conversion circuit to flow between a source terminal and a drain terminal of the first feedback input transistor and between a source terminal and a drain terminal of the second feedback input transistor, respectively, and the first feedback input transistor and the second feedback input transistor are connected in series to each other; and a first feedback output transistor and a second feedback output transistor each configured to cause the bias current to flow between a source terminal and a drain terminal of the first feedback output transistor and between a source terminal and a drain terminal of the second feedback output transistor, respectively, and the first feedback output transistor and the second feedback output transistor are connected in series with each other, and wherein the feedback resistor is connected between a gate terminal of the first feedback input transistor and a gate terminal of the second feedback input transistor.

13. The apparatus of claim 11, wherein, The voltage-current conversion circuit further includes: a buffer configured to invert a voltage of the input terminal of the Hall sensor and output a voltage corresponding to the voltage of the input terminal of the Hall sensor; and wherein the conversion transistor is configured to generate a current configured to increase when the voltage output from the buffer increases and decrease when the voltage output from the buffer decreases.

14. The apparatus of claim 10, further comprising: an amplifier configured to amplify a voltage difference between a first output terminal of the Hall sensor and a second output terminal of the Hall sensor, wherein the analog-to-digital converter is configured to output the digital value based on an output voltage of the amplifier.

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