KR102500418B1 - Apparatus for reducing offset of hall sensor and apparatus for control lens module - Google Patents

Abstract

An apparatus for reducing Hall sensor offset according to an embodiment of the present invention includes an amplifier that amplifies a voltage difference between first and second Hall sensor output terminals of a hall sensor, and a voltage of the first Hall sensor output terminal is reduced by an amplifier. electrically connected to a first switch configured to selectively bypass and transfer voltage of the second hall sensor output terminal, a second switch configured to transfer voltage by selectively bypassing the amplifier, and the first and second hall sensor output terminals, An offset reducer having a variable resistance value may be included to reduce voltage offsets of the first and second hall sensor output terminals based on the voltage bypassed by the first or second switch.

Description

Hall sensor offset reduction device and lens module control device {Apparatus for reducing offset of hall sensor and apparatus for control lens module}

The present invention relates to a hall sensor offset reduction device and a lens module control device.

In general, when a lens module moves according to an external force, a technique for fixing the relative position of the lens module to the outside is widely used.

For example, the camera module may include an optical image stabilization device that fixes the position of an internal lens module even when force is applied from the outside.

The Hall sensor may be used to measure position information of the lens module, and the Hall sensor may output a voltage that varies according to the position of the lens module. The accuracy of the optical image stabilization may increase as the accuracy of the correspondence between the output voltage of the hall sensor and the positional information of the lens module increases.

The offset of the Hall sensor may degrade the accuracy of the correspondence between the output voltage of the Hall sensor and the positional information of the lens module.

Registered Patent Publication No. 10-2105034

The present invention provides a hall sensor offset reduction device and a lens module control device.

An apparatus for reducing Hall sensor offset according to an embodiment of the present invention includes an amplifier that amplifies a voltage difference between first and second Hall sensor output terminals of a Hall sensor; a first switch configured to transfer the voltage of the first hall sensor output terminal to selectively bypass the amplifier; a second switch configured to transfer the voltage of the second hall sensor output terminal to selectively bypass the amplifier; and a voltage offset of the first and second hall sensor output terminals based on a voltage electrically connected to the first and second hall sensor output terminals and bypassed by the first or second switch. an offset reducer having a variable resistance value to reduce can include

An apparatus for controlling a lens module according to an embodiment of the present invention includes the Hall sensor offset reducing apparatus; a driver outputting a driving current based on a voltage difference between the first and second hall sensor output terminals; a driving coil receiving the driving current; a lens module disposed to move based on a driving current flowing through the driving coil; and the Hall sensor disposed such that a voltage difference between the first and second Hall sensor output terminals is determined based on the position of the lens module. can include

The hall sensor offset reduction device and the lens module control device according to an embodiment of the present invention can efficiently reduce the offset of the hall sensor without being affected by the offset level of the hall sensor or the gain of the amplifier, and relatively power consuming. may have a small and simplified structure.

1 is a diagram illustrating a hall sensor offset reduction device according to an embodiment of the present invention.
2A to 2C are diagrams illustrating equivalent circuits in first, second, and third modes of the hall sensor offset reduction device according to an embodiment of the present invention.
3 is a flowchart illustrating a process of determining a resistance value of an offset reducer of an apparatus for reducing an offset of a Hall sensor according to an embodiment of the present invention.
4A and 4B are diagrams illustrating control of a switch and an offset reducer of an apparatus for reducing an offset of a Hall sensor according to an embodiment of the present invention.
5A to 5C are diagrams illustrating a deformable structure around a switch of an apparatus for reducing an offset of a hall sensor according to an embodiment of the present invention.
6 is a diagram illustrating a variable resistor of the hall sensor offset reduction device according to an embodiment of the present invention.
7A is a graph illustrating a voltage before the Hall sensor offset reducing device controls the resistance value of the offset reducer according to an embodiment of the present invention.
7B is a graph illustrating a voltage after the Hall sensor offset reducing device controls the resistance value of the offset reducer according to an embodiment of the present invention.
8A and 8B are graphs illustrating a voltage difference between first and second Hall sensor output terminals according to bias current of an apparatus for reducing Hall sensor offset according to an embodiment of the present invention.
9 is a diagram illustrating a lens module control device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The detailed description of the present invention which follows refers to the accompanying drawings which illustrate, by way of illustration, specific embodiments in which the present invention may be practiced. It should be understood that the various embodiments of the present invention are different from each other but are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in one embodiment in another embodiment without departing from the spirit and scope of the invention. Additionally, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the invention. Accordingly, the detailed description set forth below is not to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, along with all equivalents as claimed by those claims. Like reference numbers in the drawings indicate the same or similar function throughout the various aspects.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily practice the present invention.

1 is a diagram illustrating a hall sensor offset reduction device according to an embodiment of the present invention.

Referring to FIG. 1 , the hall sensor offset reduction apparatus 100a according to an embodiment of the present invention may include an amplifier 110, a switch unit 140, and an offset reducer 120.

For example, the Hall sensor offset reduction device 100a may be implemented as an IC (Integrated Circuit), may be mounted on a substrate such as a printed circuit board, and may be electrically connected to the Hall sensor 300 through the substrate. there is. Depending on the design, the Hall sensor offset reducing device 100a and the Hall sensor 300 may be integrated into a single IC.

An equivalent circuit of the Hall sensor 400 may include first, second, third, and fourth Hall sensor resistors HR1, HR2, HR3, and HR4. The bias current IB may flow through the first, second, third, and fourth Hall sensor resistors HR1, HR2, HR3, and HR4. Specific structures of the first, second, third, and fourth Hall sensor resistors HR1, HR2, HR3, and HR4 are not limited to equivalent circuits and may be implemented in various ways.

The Hall sensor 400 may sense magnetic flux passing through the Hall sensor 400 using a Hall effect. When magnetic flux passes through the Hall sensor 400, the Hall sensor 400 can generate a Hall voltage in a direction perpendicular to the bias current IB and the magnetic flux, and the first and second Hall sensor output terminals HP , HN) may correspond to the Hall voltage. Therefore, the voltage difference between the first and second Hall sensor output terminals HP and HN may be used as a measurement value for magnetic flux passing through the Hall sensor 400 .

For example, the closer the location of a magnetic structure (eg, a magnet disposed on a lens module) that forms magnetic flux passing through the Hall sensor 400 to the Hall sensor 400, the greater the magnetic flux passing through the Hall sensor 400. can Therefore, the change value of the magnetic flux passing through the Hall sensor 400 may be proportional to the moving distance of the magnetic structure.

When the reference magnetic flux is defined and the position of the magnetic structure corresponding to the reference magnetic flux is defined, the difference value between the magnetic flux passing through the Hall sensor 400 and the reference magnetic flux may correspond to the absolute position of the magnetic structure.

For example, the criterion for the voltage difference between the first and second Hall sensor output terminals HP and HN corresponding to the reference magnetic flux may be set to 0, and the position of the magnetic structure may be defined as a center position.

However, due to an error in the arrangement/assembly process of the magnetic structure, an error in the resistance value of the Hall sensor 400, or another structure (eg, wireless power transmitter) of an electronic device in which the Hall sensor offset reduction device 100a is disposed, etc. , the actual position of the magnetic structure may deviate from the position of the defined magnetic structure. A difference between the actual position of the magnetic structure and the defined position of the magnetic structure may be defined as an offset.

In addition, the offset may be defined as a difference between a voltage difference between the first and second Hall sensor output terminals HP and HN and a reference voltage (eg, 0) when the actual position of the magnetic structure is defined. there is. For example, when the criterion for the voltage difference between the first and second Hall sensor output terminals HP and HN is defined as 0, the first and second first and second hall sensor positions when the actual position of the magnetic structure is the position of the defined magnetic structure A voltage difference between the Hall sensor output terminals HP and HN may be greater than or less than zero.

The amplifier 110 may amplify a voltage difference between the first and second Hall sensor output terminals HP and HN of the Hall sensor 400 .

For example, the amplifier 110 may be implemented as a (non)inverting amplifier circuit in which an operational amplifier and a plurality of resistors are combined, and is proportional to the voltage difference between the first and second hall sensor output terminals HP and HN. The amplified voltage can be output. The voltage amplified by the amplifier 110 may be proportional to the voltage difference between the first and second Hall sensor output terminals HP and HN.

A gain of the amplifier 110 may be determined according to a relationship between resistance values of the plurality of resistors. The amplifier 110 having a low gain may be advantageous when a wide magnetic flux sensing range of the Hall sensor 400 is required, and the amplifier 110 having a high gain has a high magnetic flux sensing resolution of the Hall sensor 400. This can be advantageous when highly demanding.

If there is an offset in the Hall sensor 400, the voltage difference between the first and second Hall sensor output terminals HP and HN when the actual position of the magnetic structure is the position of the defined magnetic structure may correspond to the offset. and can be amplified by the amplifier 110. That is, the amplifier 110 may amplify a voltage corresponding to the magnetic flux passing through the Hall sensor 400 and a voltage corresponding to the offset of the Hall sensor 400 together.

Since the output voltage range of the amplifier 110 is not infinite, the output voltage of the amplifier 110 may fall to the maximum or minimum value of the output voltage range due to offset. At this time, the output voltage of the amplifier 110 may always correspond to the maximum value or minimum value of the output voltage range regardless of the magnetic flux passing through the Hall sensor 400 . That is, the input voltage difference range of the amplifier 110 may be cut out by the range in which the output voltage of the amplifier 110 takes the maximum value or minimum value of the output voltage range.

When the output voltage of the amplifier 110 is at the maximum or minimum value of the output voltage range due to offset, it may be difficult to determine the offset level of the hall sensor 400 from the output voltage of the amplifier 110. That is, it may be difficult for components electrically connected to the output terminal of the amplifier 110 to detect the offset level of the Hall sensor 400 from the output voltage of the amplifier 110 .

The switch unit 140 may include a first switch 141 and a second switch 142 . For example, each of the first and second switches 141 and 142 may be implemented as a transistor that receives a control voltage through a gate terminal and changes an equivalent resistance value between a drain/source terminal based on the control voltage. Each of the first and second switches 141 and 142 may operate in an on state when the input control voltage is high and operate in an off state when the input control voltage is low. Each of the first and second switches 141 and 142 may transfer a voltage from one of the drain/source terminals to the other in an on state, and may block voltage transfer between the drain/source terminals in an off state.

The first switch 141 may be configured such that the voltage of the first hall sensor output terminal HP is transmitted by selectively bypassing the amplifier 110, and the second switch 142 is configured to transfer the voltage to the second hall sensor output terminal HN. ) may be configured to be passed selectively bypassing the amplifier 110.

The voltages of the first and second Hall sensor output terminals HP and HN transmitted by selectively bypassing the amplifier 110 are cut by the range where the output voltage of the amplifier 110 spans the maximum or minimum value of the output voltage range. Since it does not cause an out-of-phase phenomenon, it can be efficiently used to determine the offset level of the Hall sensor 400 before being amplified by the amplifier 110.

The offset reducer 120 is electrically connected to the first and second hall sensor output terminals HP and HN, and based on the voltage bypassed by the first or second switches 141 and 142, the first and a variable resistance value to reduce a voltage offset of the second hall sensor output terminals HP and HN.

When the resistance value of the offset reducer 120 is changed, the voltage of at least one of the first and second Hall sensor output terminals HP and HN may be changed, and the first and second Hall sensor output terminals HP , HN) can be changed. Therefore, the voltage difference between the first and second hall sensor output terminals HP and HN corresponds to the voltage reference of the first and second hall sensor output terminals HP and HN through the resistance value change of the offset reducer 120. It can be approximated and equal to the above criterion.

Accordingly, in the Hall sensor offset reduction device 100a according to an embodiment of the present invention, the Hall sensor is cut out by a range where the output voltage of the amplifier 110 is applied to the maximum or minimum value of the output voltage range. The offset of (400) can be effectively reduced. That is, the Hall sensor offset reduction device 100a according to an embodiment of the present invention efficiently reduces the offset of the Hall sensor 400 without being affected by the offset level of the Hall sensor 400 or the gain of the amplifier 110. can be reduced

In addition, since the switch unit 140 and the offset reducer 120 consume less power than the active element and may have a simplified structure, the offset of the Hall sensor 400 can be effectively reduced.

Referring to FIG. 1 , the hall sensor offset reduction device 100a according to an embodiment of the present invention may further include at least one of a bias provider 160, an AD converter 130a, and a multiplexer 150. .

The bias provider 160 may provide the bias current IB to the input terminal HB of the Hall sensor 300 . For example, the bias provider 160 may be composed of a circuit that generates a bias current IB robustly against an external environment or process variation, such as a bandgap reference circuit, and is connected to a gate terminal of a transistor. A bias current IB may be formed between the drain/source terminals of the transistor according to the applied voltage. For example, the bias provider 160 may be configured to receive a digital control signal and generate an analog voltage corresponding to the digital control signal, and convert the analog voltage to a gate terminal of the transistor or a part of a bandgap reference circuit. can be applied to the transistor.

The offset reducer 120 may be electrically connected between the first and second Hall sensor output terminals HP and HN and the bias provider 160 . That is, the current generated by the bias provider 160 may be the sum of the bias current IB and the current flowing through the offset reducer 120 .

The voltage across both ends of the offset reducer 120 may be a product of a current flowing through the offset reducer 120 and a resistance value of the offset reducer 120 . The voltage of one end of the offset reducer 120 may correspond to the output voltage of the bias provider 160, and the output voltage of the bias provider 160 may be stable due to the characteristics of the bias provider 160. Therefore, since the voltages of the first and second Hall sensor output terminals HP and HN, which are the other ends of the offset reducer 120, can be stably changed according to the change in the resistance value of the offset reducer 120, the present invention The Hall sensor offset reduction device 100a according to an embodiment of the present invention can efficiently reduce the offset of the Hall sensor 400 .

The offset reducer 120 may include a first variable resistor 121a and a second variable resistor 122a.

The first variable resistor 121a is electrically connected between the bias provider 160 and the first Hall sensor output terminal HP, and is variable based on the voltage bypassed by the first switch 141 and transferred. may have a resistance value.

The second variable resistor 122a is electrically connected between the bias provider 160 and the second Hall sensor output terminal HN, and is variable based on the voltage bypassed by the second switch 142 and transferred. may have a resistance value.

When the resistance value of the first variable resistor 121a and the resistance value of the second variable resistor 122a are different, the voltage difference between the first and second Hall sensor output terminals HP and HN is the difference between the first and second variable resistors. It may be different from that in the case where (121a, 122a) is not present.

For example, when the resistance value of the first variable resistor 121a is greater than the resistance value of the second variable resistor 122a, the voltage of the first hall sensor output terminal HP is applied to the second hall sensor output terminal HN. ) may be affected by a larger voltage drop than the voltage of Accordingly, the voltage of the first Hall sensor output terminal HP may be lower than that when the first variable resistor 121a is not present.

The AD converter 130a is electrically connected to the output terminal of the amplifier 110 and may be configured to convert an analog value into a digital value. The digital value output from the AD converter 130a may be used to control the position of a magnetic structure (eg, a magnet disposed in a lens module) forming a magnetic flux passing through the Hall sensor 400 .

The total number of digital values from the minimum value to the maximum value output from the AD converter 130a may be set to be close to the maximum and minimum values of the output voltage range of the amplifier 110. Accordingly, the AD converter 130a may cover a wide magnetic flux sensing range of the Hall sensor 400 or cover a magnetic flux sensing range so that the magnetic flux sensing resolution of the Hall sensor 400 is high. Accordingly, the output value of the AD converter 130a may also take the maximum or minimum value due to the offset of the hall sensor 400.

The voltages of the first and second Hall sensor output terminals HP and HN, which are transferred by selectively bypassing the amplifier 110, are cut-out by the range where the output value of the AD converter 130a is the maximum or minimum value. Since it does not cause, the digital value output from the AD converter 130a can be efficiently used in the controller that controls the resistance value of the offset reducer 120.

The first and second switches 141 and 142 may be connected so that the voltages of the first and second Hall sensor output terminals HP and HN selectively bypass the amplifier 110 and be transmitted to the AD converter 130a.

The multiplexer 150 may be electrically connected between the first and second switches 141 and 142 and the AD converter 130a. The multiplexer 150 may operate to electrically connect one of the first and second switches 141 and 142 and the amplifier 110 to the AD converter 130a and separate the other from the AD converter 130a. . Accordingly, the single AD converter 130a outputs a digital value corresponding to the voltage difference between the first and second hall sensor output terminals HP and HN and the first and second hall sensor output terminals HP and HN, respectively. One of the digital values corresponding to the voltage may be selectively generated.

2A to 2C are diagrams illustrating equivalent circuits in first, second, and third modes of the hall sensor offset reduction device according to an embodiment of the present invention.

Referring to FIG. 2A , the hall sensor offset reduction device 100a-1 operating in the first mode can control the first switch 141 to be in an on state, and the voltage of the first hall sensor output terminal HP. Based on this, the resistance value of the first variable resistor 121a may be adjusted.

Referring to FIG. 2B , the hall sensor offset reduction device 100a-2 operating in the second mode can control the second switch 142 to be in an on state, and the voltage of the second hall sensor output terminal HN. Based on this, the resistance value of the second variable resistor 122a may be adjusted.

Referring to FIG. 2C , the Hall sensor offset reduction device 100a-3 operating in the third mode includes a first variable resistor 121a_F having a fixed resistance value and a second variable resistor 122a_F having a fixed resistance value. The voltages of the first and second Hall sensor output terminals HP and HN may be used as measurement values for magnetic flux passing through the Hall sensor 400 in a state in which the offset is reduced by .

3 is a flowchart illustrating a process of determining a resistance value of an offset reducer of an apparatus for reducing an offset of a Hall sensor according to an embodiment of the present invention.

Referring to FIG. 3 , the hall sensor offset reduction device operating in the first mode controls the lens position so that the lens (an object on which a magnetic structure that forms magnetic flux passing through the hall sensor is disposed) is located at the center (S110). and outputs the bias current to the Hall sensor (S120), electrically connects the first Hall sensor output terminal and the AD converter (ADC) (S130), controls the resistance value of the first variable resistor (S140), The resistance value of the first variable resistor may be repeatedly controlled until the output of the AD converter ADC falls within the target value range (S150).

Referring to FIG. 3, the Hall sensor offset reduction device operating in the second mode electrically connects the second Hall sensor output terminal and the AD converter (ADC) (S160), and controls the resistance value of the second variable resistor. (S170), and the resistance value of the second variable resistor may be repeatedly controlled (S180) until the output of the AD converter (ADC) falls within the target value range.

That is, in the Hall sensor offset reduction device according to an embodiment of the present invention, the resistance value of the first variable resistor is determined in the first mode, the resistance value of the first variable resistor is fixed in the second mode, and the resistance value of the second variable resistor is determined. Resistance values of the first and second variable resistors may be controlled to determine the resistance values.

Accordingly, the Hall sensor offset reducing device can further reduce the effect of the voltages of the first and second Hall sensor output terminals on the common mode voltage in the process of reducing the offset of the Hall sensor, thereby reducing the offset more accurately.

Referring to FIG. 3 , in the Hall sensor offset reduction device operating in the third mode, in a state in which the offset reduction is completed (S190), the voltages of the first and second Hall sensor output terminals are applied to the magnetic flux passing through the Hall sensor 400. can be used as a measure for

4A and 4B are diagrams illustrating control of a switch and an offset reducer of an apparatus for reducing an offset of a Hall sensor according to an embodiment of the present invention.

Referring to FIG. 4A , the hall sensor offset reduction apparatus 100b according to an embodiment of the present invention controls the on-off states of the first and second switches 141 and 142 and the offset reducer 120 A controller 170 for controlling the resistance value of may be further included.

For example, the controller 170 may have a structure similar to that of a processor, directly transfers a digital control signal to the first and second switches 141 and 142 or the offset reducer 120, or converts a digital control signal to an analog voltage. It can be converted to and transmitted to the first and second switches 141 and 142 or the offset reducer 120. That is, the controller 170 may include a digital circuit and may further include an analog circuit according to design.

The controller 170 controls the first switch 141 to be turned on in the first mode, controls the resistance value of the first variable resistor 121a, and controls the second switch 142 to be turned on in the second mode. and control the resistance value of the second variable resistor 122a.

In addition, the controller 170 may control the bias provider 160 to provide a predetermined current to the Hall sensor 400 while controlling the resistance of the offset reducer 120. . For example, the predetermined current may be the same as or different from the bias current IB.

In addition, the controller 170 controls the resistance value of the offset reducer 120 so that the amplifier 110 is deactivated and the amplifier 110 is activated after controlling the resistance value of the offset reducer 120 ( 110) can be controlled. Accordingly, the total power consumption of the hall sensor offset reduction apparatus 100b according to an embodiment of the present invention may be reduced.

Referring to FIG. 4B , the hall sensor offset reduction apparatus 100c according to an embodiment of the present invention may receive a control signal from an external processor (eg, the processor shown in FIG. 9 ), and the control signal It may be transferred to at least some of the first and second switches 141 and 142, the offset reducer 120, the bias provider 160, the amplifier 110, and the AD converter 130a.

5A to 5C are diagrams illustrating a deformable structure around a switch of an apparatus for reducing an offset of a hall sensor according to an embodiment of the present invention.

Referring to FIG. 5A , the Hall sensor offset reduction apparatus 100d according to an embodiment of the present invention may have a structure in which the multiplexer shown in FIG. 1 is omitted.

For example, the AD converter 130b may have a plurality of independent AD conversion channels, and one of the plurality of AD conversion channels is dependent on the voltage difference between the first and second hall sensor output terminals HP and HN. It may be configured to output a corresponding digital value, and the rest of the plurality of AD conversion channels may be configured to output a digital value corresponding to the voltage of each of the first and second Hall sensor output terminals HP and HN. . Depending on the design, the plurality of AD conversion channels may be spaced apart from each other.

Referring to FIG. 5B , the Hall sensor offset reduction apparatus 100e according to an embodiment of the present invention may further include a first buffer 143 and a second buffer 144 .

The amplifier 110 is easily designed to have an input impedance (eg, infinite) higher than the output impedance due to the characteristics of the amplifier 110, but the first and second switches 141 and 142 when in an on state have an output It can be relatively difficult to have an input impedance higher than the impedance. When the input impedance of the amplifier 110 and the input impedance of the first and second switches 141 and 142 are different, the voltage amplified by the amplifier 110 and the voltage transmitted through the first and second switches 141 and 142 Voltage may vary slightly.

The first buffer 143 may be disposed on a path electrically connected to the first switch 141 bypassing the amplifier 110 and may be configured to have an input impedance greater than an output impedance.

The second buffer 144 may be disposed on a path electrically connected to the second switch 142 bypassing the amplifier 110 and may be configured to have an input impedance greater than an output impedance.

Accordingly, since the input impedance of the amplifier 110 and the input impedance of the first and second switches 141 and 142 may be similar or identical, the voltage amplified by the amplifier 110 and the first and second switches 141 , 142) may be the same, and the hall sensor offset reduction device 100e according to an embodiment of the present invention can more accurately reduce the offset.

For example, the first and second buffers 143 and 144 may have a structure in which an output terminal and a second input terminal of an operational amplifier are connected to each other, and may be configured to receive a voltage through the first input terminal of the operational amplifier. . Accordingly, the input impedance of the first and second buffers 143 and 144 may ideally be close to infinity, and the output impedance may ideally be close to zero.

Referring to FIG. 5C , the hall sensor offset reduction device 100f according to an embodiment of the present invention may further include a first bypass amplifier 145 and a second bypass amplifier 146.

The first bypass amplifier 145 may be disposed on a path electrically connected to the first switch 141 bypassing the amplifier 110 and may be configured to amplify an input voltage.

The second bypass amplifier 146 may be disposed on a path electrically connected to the second switch 142 bypassing the amplifier 110 and may be configured to amplify an input voltage.

For example, each of the first and second bypass amplifiers 145 and 146 may be configured to have a gain lower than that of the amplifier 110 . Since each of the first and second bypass amplifiers 145 and 146 may be configured to easily have a large impedance due to the nature of the amplifier, the hall sensor offset reduction device 100f according to an embodiment of the present invention can more accurately reduce the offset. can

6 is a diagram illustrating a variable resistor of the hall sensor offset reduction device according to an embodiment of the present invention.

Referring to FIG. 6 , the first variable resistor 121b includes a plurality of first resistors 121-1, 121-2, 121-3, and 121-4, a plurality of first resistance switches 121-5, 121- 6, 121-7) and a resistance value controller 121-0.

The plurality of first resistors 121-1, 121-2, 121-3, and 121-4 may be connected in series, but may be connected in parallel according to design and may have a structure in which a series connection and a parallel connection are combined. .

The resistance value controller 121-0 may control the on-off state of the plurality of first resistance switches 121-5, 121-6, and 121-7 based on the resistance value control signal transmitted from the controller or processor. there is.

The plurality of first resistance switches 121-5, 121-6, and 121-7 have a total resistance value of the plurality of first resistors 121-1, 121-2, 121-3, and 121-4. It may be configured to vary according to a combination of on-off states of the one-resistance switches 121-5, 121-6, and 121-7. The plurality of first resistance switches 121-5, 121-6, and 121-7 may be connected in parallel to the plurality of first resistors 121-1, 121-2, 121-3, and 121-4.

7A is a graph illustrating a voltage before the Hall sensor offset reducing device controls the resistance value of the offset reducer according to an embodiment of the present invention.

Referring to FIG. 7A, the voltage difference (Hall-diff output) between the first and second Hall sensor output terminals may be an offset voltage greater than 0 when the position of the lens is at the center. .

Since the product of the amplifier's gain and the offset voltage can be greater than the maximum value of the amplifier's output voltage range (eg 2.8V), the amplifier's output voltage (HAMP output) is the maximum regardless of the lens position. (e.g. 2.8V).

The output value (ADC output) of the AD converter may take a maximum value (eg 4095code) corresponding to the output voltage (HAMP output) of the amplifier.

7B is a graph illustrating a voltage after the Hall sensor offset reducing device controls the resistance value of the offset reducer according to an embodiment of the present invention.

Referring to FIG. 7B , a voltage difference (Hall-diff output) between the first and second hall sensor output terminals may be 0 when the position of the lens is at the center.

Therefore, the output voltage (HAMP output) of the amplifier may be lower than the maximum value (eg, 2.8V), and the output value (ADC output) of the AD converter may be lower than the maximum value (eg, 4095code).

8A and 8B are graphs illustrating a voltage difference between first and second Hall sensor output terminals according to a bias current of an apparatus for reducing Hall sensor offset according to an embodiment of the present invention.

Referring to FIG. 8A, the voltage difference (Hall-diff output) between the first and second Hall sensor output terminals when there is an offset of the Hall sensor and a large bias current (IBL1) depends on a change in the position of the lens. The voltage difference (Hall-diff output) between the first and second Hall sensor output terminals when the offset of the Hall sensor is present and the bias current is small (IBS1) can be relatively large. Depending on the change, it can change in a relatively small width.

The offset of the Hall sensor may make the voltage difference (Hall-diff output) of the first and second Hall sensor output terminals dependent on the bias current when the position of the lens is at the center. Thus, the offset of the Hall sensor may limit the range of the bias current.

Referring to FIG. 8B, when the offset of the Hall sensor is removed and the bias current is large (IBL2), the voltage difference (Hall-diff output) between the first and second Hall sensor output terminals is dependent on the change in the position of the lens. The voltage difference (Hall-diff output) between the first and second Hall sensor output terminals when the offset of the Hall sensor is removed and the current is small (IBS2) is the position of the lens. It can change in a relatively small width according to the change of .

When the offset of the Hall sensor is removed and the position of the lens is centered, the voltage difference between the first and second Hall sensor output terminals (Hall-diff output) may be substantially independent of the bias current. . Accordingly, the Hall sensor offset reduction device according to an embodiment of the present invention can broaden the bias current range by reducing the offset.

9 is a diagram illustrating a lens module control device according to an embodiment of the present invention.

Referring to FIG. 9 , an apparatus for controlling a lens module according to an embodiment of the present invention includes a hall sensor offset reduction device 100c, a driver 220, a driving coil 230, a lens module 210, and a hall sensor 400. ) may be included.

The driver 220 may receive the output value of the AD converter of the hall sensor offset reduction device 100c, and the voltage difference between the first and second hall sensor output terminals of the hall sensor 400 (corresponding to the output value) Based on this, the driving current can be output.

For example, the actuator 220 may have an Optical Image Stabilization (OIS) control structure or an Auto Focus (AF) control structure, and may include a driving circuit generating a driving current based on an output value of the control structure. Depending on the design, the control structure may be included in the Hall sensor offset reduction device 100c, and the Hall sensor offset reduction device 100c and the driver 220 may be implemented as a single IC.

The driving coil 230 may receive driving current. For example, the driving coil 230 may be disposed near the magnetic structure 211 of the lens module 210 . That is, the lens module 210 may be arranged to move based on a driving current flowing through the driving coil 230 .

The lens module 210 may move according to the force applied to the magnetic structure 211 in response to the magnetic flux of the driving coil 230 . At this time, the lens module 210 may move so that the magnetic flux changes in the opposite direction to the change in the magnetic flux passing through the Hall sensor 400 . Accordingly, the absolute position of the lens module 210 may be substantially fixed, and an image acquired by the lens module 210 may be stable.

The Hall sensor 400 may be arranged such that a voltage difference between the first and second Hall sensor output terminals of the Hall sensor 400 is determined based on the position of the lens module 210 .

For example, at least one of the Hall sensor 400 , the actuator 220 , the Hall sensor offset reducing device 100c and the driving coil 230 may be disposed on the first substrate 240 .

Referring to FIG. 9 , the lens module control device according to an embodiment of the present invention controls the on-off states of the first and second switches of the Hall sensor offset reducing device 100c and controls the resistance value of the offset reducer. It may include a processor 270 that does.

The processor 270 controls the first switch to be turned on in the first mode and controls the resistance value of the first variable resistor, and controls the second switch to be turned on in the second mode and controls the resistance value of the second variable resistor to be You can control it.

For example, the processor 270 may be implemented as an image signal processor (ISP), receive image information from the image sensor 262 on the first support member 261, and process the information to the driver 220. ) can be provided. Depending on the design, processor 270 may be separate from or integrated with the ISP.

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

In the above, the present invention has been described as an embodiment, but the present invention is not limited to the above-described embodiments, and those skilled in the art in the field to which the invention pertains without departing from the gist of the present invention claimed in the claims Anyone can make various variations.

100a, 100c: Hall sensor offset reduction device
110: amplifier
120: offset reducer
121a: first variable resistor
122a: second variable resistor
130a: AD (Analog-Digital) converter
140: switch unit
141: first switch
142: second switch
143: first buffer
144: second buffer
145: first bypass amplifier
146: second bypass amplifier
150: multiplexer
160: bias provider
170: controller
210: lens module
220: actuator
270: processor
400: hall sensor

Claims (16)

an amplifier amplifying a voltage difference between first and second hall sensor output terminals of a hall sensor;
a first switch configured to transfer the voltage of the first hall sensor output terminal to selectively bypass the amplifier;
a second switch configured to transfer the voltage of the second hall sensor output terminal to selectively bypass the amplifier; and
Voltage offsets of the first and second Hall sensor output terminals are electrically connected to the first and second Hall sensor output terminals, based on the voltage bypassed and transferred by the first or second switch. an offset reducer having a variable resistance value to reduce; Hall sensor offset reduction device comprising a.
According to claim 1,
Further comprising a bias provider providing a bias current to the Hall sensor;
The offset reducer is electrically connected between the first and second hall sensor output terminals and the bias provider.
The method of claim 2, wherein the offset reducer,
a first variable resistor electrically connected between the bias provider and the first hall sensor output terminal and having a variable resistance value based on a voltage bypassed by the first switch; and
a second variable resistor electrically connected between the bias provider and the second Hall sensor output terminal and having a variable resistance value based on the voltage bypassed by the second switch; Hall sensor offset reduction device comprising a.
According to claim 1,
Further comprising an AD converter electrically connected to the output terminal of the amplifier and configured to convert analog values into digital values;
The first and second switches are connected such that the voltages of the first and second hall sensor output terminals selectively bypass the amplifier and are transmitted to the AD converter.
According to claim 4,
The hall sensor offset reduction device further comprises a multiplexer electrically connected between the first and second switches and the AD converter.
According to claim 1,
a first buffer disposed on a path electrically connected to the first switch bypassing the amplifier and configured to have an input impedance greater than an output impedance; and
a second buffer disposed on a path electrically connected to the second switch bypassing the amplifier and configured to have an input impedance greater than an output impedance; Hall sensor offset reduction device further comprising a.
According to claim 1,
a first bypass amplifier disposed on a path electrically connected to the first switch bypassing the amplifier and configured to amplify an input voltage; and
a second bypass amplifier disposed on a path electrically connected to the second switch bypassing the amplifier and configured to amplify an input voltage; Hall sensor offset reduction device further comprising a.
According to claim 1,
The Hall sensor offset reducing device further includes a controller controlling on-off states of the first and second switches and controlling a resistance value of the offset reducer.
The method of claim 8, wherein the offset reducer,
a first variable resistor electrically connected to the first Hall sensor output terminal and having a variable resistance value; and
a second variable resistor electrically connected to the second hall sensor output terminal and having a variable resistance value; including,
The controller controls the first switch to be in an on state in a first mode and controls the resistance value of the first variable resistor, and controls the second switch to be in an on state in a second mode and controls the resistance of the second variable resistor. Hall sensor offset reduction device to control the value.
According to claim 9,
The controller determines the resistance value of the first variable resistor in the first mode, and fixes the resistance value of the first variable resistor and determines the resistance value of the second variable resistor in the second mode. and a Hall sensor offset reducing device controlling a resistance value of the second variable resistor.
According to claim 8,
Further comprising a bias provider providing a bias current to the Hall sensor;
The controller controls the bias provider so that the bias provider provides a predetermined current to the Hall sensor while controlling the resistance value of the offset reducer.
According to claim 8,
wherein the controller controls the amplifier so that the amplifier is deactivated while controlling the resistance value of the offset reducer and the amplifier is activated after controlling the resistance value of the offset reducer.
The hall sensor offset reduction device of claim 1;
a driver outputting a driving current based on a voltage difference between the first and second hall sensor output terminals;
a driving coil receiving the driving current;
a lens module disposed to move based on a driving current flowing through the driving coil; and
the hall sensor disposed such that a voltage difference between the first and second hall sensor output terminals is determined based on the position of the lens module; Lens module control device comprising a.
According to claim 13,
The lens module control device further comprising a processor configured to control on-off states of the first and second switches and to control a resistance value of the offset reducer.
The method of claim 14, wherein the offset reducer,
a first variable resistor electrically connected to the first hall sensor output terminal and having a variable resistance value; and
a second variable resistor electrically connected to the second hall sensor output terminal and having a variable resistance value; including,
The processor controls the first switch to be turned on in a first mode and controls the resistance of the first variable resistor, and in a second mode, controls the second switch to be turned on and controls the resistance of the second variable resistor. Lens module control device that controls the value.
According to claim 15,
The Hall sensor offset reduction device further includes a bias provider providing a bias current to the Hall sensor,
The first variable resistor is electrically connected between the bias provider and the first Hall sensor output terminal;
The second variable resistor is electrically connected between the bias provider and the second hall sensor output terminal.

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