Voice coil motor driving circuit and driving integrated circuit

Abstract

Voice coil motor driving circuits are provided. The voice coil motor driving circuit includes a first circuit in which a first top transistor, a second top transistor, a first bottom transistor, and a second bottom transistor are connected to each other by a bridge structure, and the first circuit includes a first switch, a second switch, and a voice coil motor; a second circuit including a third bottom transistor, a fourth bottom transistor, and a current source; and a power voltage control circuit connected to the first circuit and the second circuit, respectively, and configured to control a power voltage of the second circuit to match a reference voltage of the first circuit based on feedback operation, and the power voltage control circuit can be connected to a node between the first switch and the second switch. A driving integrated circuit is also provided.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0180141, filed on December 6, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The following description relates to a voice coil motor drive circuit with adaptive control of the supply voltage and a drive integrated circuit configured to drive a voice coil motor. Background Technology

[0004] As the performance of smartphone camera modules improves, the weight of optical systems, such as lenses and prisms, also increases. However, to drive such relatively heavy optical systems to perform autofocus (AF) or optical image stabilization (OIS) operations, increased driving force is required.

[0005] However, since the power voltage of the driver integrated circuit (IC) used to drive the voice coil motor for AF or OIS operation is typically limited to a maximum of 3.3V, it is possible to increase the number of coils or reduce the air gap to ensure driving force. However, in this case, there may be risks such as difficulty in miniaturizing the camera module and reduced mass production yield.

[0006] Furthermore, due to the offset characteristics of the driver IC used to drive the voice coil motor, a constant error value appears in the coil drive current, which may make it difficult to control the voice coil motor accurately and may cause drive noise.

[0007] Therefore, a circuit is needed to drive a voice coil motor that minimizes the offset characteristics and increases the maximum value of the drive current to ensure high driving force. Summary of the Invention

[0008] The summary portion of this invention is intended to provide a brief overview of the chosen 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 is it intended to help determine the scope of the claimed subject matter.

[0009] In general, the voice coil motor drive circuit includes: a first circuit in which a first top transistor, a second top transistor, a first bottom transistor, and a second bottom transistor are connected to each other via a bridge structure, and the first circuit also includes a first switch, a second switch, and a voice coil motor; a second circuit including a third bottom transistor, a fourth bottom transistor, and a current source; and a power voltage control circuit connected to the first circuit and the second circuit respectively, and configured to control the power voltage of the second circuit to match a reference voltage of the first circuit based on feedback operation, wherein the power voltage control circuit is connected to a node between the first switch and the second switch.

[0010] The power voltage control circuit can be configured to control the power voltage of the second circuit to be the same as the reference voltage of the first circuit.

[0011] The first switch and the second switch can be connected in series to connect the node between the first top transistor and the first bottom transistor to the node between the second top transistor and the second bottom transistor.

[0012] The power voltage control circuit can be a DC-DC converter.

[0013] The power voltage control circuit can be configured to control the power voltage to be greater than or less than the input voltage of the power voltage control circuit.

[0014] The power voltage control circuit can be configured to operate in buck mode when the input voltage is greater than the power voltage, and to operate in boost mode when the input voltage is less than the power voltage.

[0015] The power voltage control circuit may include an error amplifier configured to receive a reference voltage and configured to output a feedback voltage.

[0016] The power voltage control circuit may further include: a sawtooth wave generator configured to generate a sawtooth wave; and a comparator configured to compare the feedback voltage with the sawtooth voltage of the sawtooth wave to generate a pulse width modulation signal.

[0017] The power voltage control circuit may include at least one node connected to each of the MOSFET, diode, and inductor.

[0018] Power voltage control circuits may include coupling inductors.

[0019] The power voltage control circuit may include multiple switching elements, and the power voltage control circuit may be configured to operate independently in one of a buck mode and a boost mode based on a combination of multiple switching elements.

[0020] The power voltage control circuit may include a switching element, and the switching element may be configured to perform a switching operation of turning on or off when the input voltage of the power voltage control circuit is less than the power voltage.

[0021] The power voltage control circuit may include at least one node connected to an inductor and an N-type semiconductor transistor.

[0022] One of the diode and the P-type semiconductor transistor can also be connected to the at least one node.

[0023] The voice coil motor can be configured to connect the node between the first top transistor and the first bottom transistor and the node between the second top transistor and the second bottom transistor.

[0024] The first and second top transistors can be directly connected to the electrical voltage node, and the first, second, third, and fourth bottom transistors can be directly connected to ground respectively.

[0025] The first and second top transistors can be P-type semiconductor transistors, and the first, second, third, and fourth bottom transistors can be N-type semiconductor transistors.

[0026] The gate terminal of the first bottom transistor can be connected to the gate terminal and drain terminal of the fourth bottom transistor, and the gate terminal of the second bottom transistor can be connected to the gate terminal and drain terminal of the third bottom transistor.

[0027] In another general aspect, the driver integrated circuit (IC) configured to drive a voice coil motor may include: a driver, including a voice coil motor drive circuit; a communication device configured to communicate with an external host; a sensor configured to obtain position information of a lens in a camera module; a controller configured to generate signals for driving the lens to control the driver based on the position information of the lens and commands input from the external host; and a power device configured to generate power for performing the operation.

[0028] The driver may also include multiple channels, and the voice coil motor drive circuitry can be selectively connected to any one of the multiple channels.

[0029] Other features and aspects will become apparent from the following detailed description and accompanying drawings. Attached Figure Description

[0030] Figure 1 The internal configuration of an exemplary driver IC for driving a voice coil motor is shown according to one or more embodiments.

[0031] Figure 2A circuit for driving a voice coil motor according to one or more embodiments is shown.

[0032] Figure 3 It shows that from Figure 2 The circuit omits the power voltage control circuit and the circuits for the first and second switches of the first circuit.

[0033] Figure 4 It shows in Figure 3 The equivalent circuit in the circuit when the third switch is turned on and the fourth switch is turned off.

[0034] Figure 5 A comparison was shown. Figure 2 circuit and Figure 3 A graph showing the power consumption of each component in the circuit.

[0035] Figure 6 This shows the maximum value I of the drive current when the power voltage VM is fixed at 3.3V. max The curve graph.

[0036] Figure 7 This shows the maximum value I of the drive current when the power voltage VM varies between 3.3V and 5V. max The curve graph.

[0037] Figure 8 This shows the maximum value I of the drive current when the power voltage VM varies between 0V and 5V. max The curve graph.

[0038] Figure 9 This is a circuit diagram illustrating an exemplary embodiment of a power voltage control circuit included in a circuit for driving a voice coil motor, according to one or more embodiments.

[0039] Figures 10A to 10E It is shown Figure 9 The simulation results of the circuit are shown in the graph.

[0040] Figure 11 It is shown Figure 9 A circuit diagram illustrating a modified example of a power voltage control circuit.

[0041] Figure 12A and Figure 12B It shows when Figure 11 The input voltage V of the circuit in A view of current flow when the voltage is above the electrical voltage VM.

[0042] Figure 13A and Figure 13B It shows when Figure 11 The input voltage V of the circuit inA view of current flow below the power voltage VM.

[0043] Figures 14A to 14F It is shown Figure 11 The simulation results of the circuit are shown in the graph.

[0044] Figure 15 It is shown Figure 9 A circuit diagram of another modified example of a power voltage control circuit.

[0045] Figures 16A to 16E It is shown Figure 15 The simulation results of the circuit are shown in the graph.

[0046] Throughout the accompanying drawings and detailed embodiments, the same reference numerals refer to the same elements unless otherwise described. For purposes of clarity, illustration, and convenience, the drawings may not be drawn to scale, and the relative dimensions, scale, and descriptions of elements in the drawings may be exaggerated. Detailed Implementation

[0047] The following detailed embodiments are provided to aid the reader in gaining a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will become apparent upon understanding the disclosure of this application. For example, the order of operations described herein and / or the sequence of operations described herein are merely examples and are not limited to the order set forth herein, except for the order of operations and / or the order of operations which must occur in a specific sequence, but can be varied, as will become apparent upon understanding the disclosure of this application. As another example, the order of operations and / or the order of operations can be performed in parallel, except for the order of operations and / or at least a portion of the order of operations which must occur in a sequence (e.g., a specific sequence). Furthermore, for clarity and conciseness, descriptions of features known upon understanding the disclosure of this application may be omitted.

[0048] Although terms such as “first,” “second,” and “third,” or A, B, (a), (b), may be used herein to describe various components, parts, regions, layers, or sections, these components, parts, regions, layers, or sections are not limited by these terms. Each of these terms is not intended to define, for example, the importance, sequence, or order of the corresponding component, part, region, layer, or section, but only to distinguish the corresponding component, part, region, layer, or section from other components, parts, regions, layers, or sections. Therefore, without departing from the teachings of the examples described herein, the first component, first part, first region, first layer, or first section mentioned in these examples may also be referred to as the second component, second part, second region, second layer, or second section.

[0049] Throughout this specification, when a component, element, or layer is described as "on another component, element, or layer," "connected to," "attached to," or "joined to" another component, element, or layer, it may be directly "on another component, element, or layer," directly "connected to," "attached to," or "joined to" another component, element, or layer (e.g., in contact with another component, element, or layer), or one or more other components, elements, or layers may reasonably be present between that component, element, or layer and that other component, element, or layer. When a component, element, or layer is described as "directly on another component, element, or layer," "directly connected to," "directly attached to," or "directly joined to" another component, element, or layer, then there are no other components, elements, or layers between that component, element, or layer and that other component, element, or layer. Similarly, expressions such as "between" and "directly between," and "adjacent" and "directly adjacent" may also be interpreted as described above.

[0050] The terminology used herein is for describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the terms “a,” “an,” and “the” are intended to equally include the plural forms. As non-limiting examples, the terms “comprising,” “including,” and “having” indicate the presence of the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof, or alternatives to the stated features, quantities, operations, components, elements, and / or combinations thereof. Furthermore, while one embodiment may describe the presence of the stated features, quantities, operations, components, elements, and / or combinations thereof using the terms “comprising,” “including,” and “having,” other embodiments may exist in which one or more of the stated features, quantities, operations, components, elements, and / or combinations thereof are absent.

[0051] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more items. Phrases such as “at least one of A, B, and C” are intended to have a disjunctive meaning, and these phrases also include examples in which one or more of A, B, and C may be present (e.g., any combination of one or more of A, B, and C), unless the corresponding description and implementation require that the enumeration (e.g., “at least one of A, B, and C”) be interpreted as having a conjunctive meaning.

[0052] The features described herein may be embodied in various forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein are provided merely to illustrate some of the many possible ways in which the methods, apparatus, and / or systems described herein will become apparent upon understanding the disclosure of this application. In this document, the use of the term “may” (e.g., regarding what an example or implementation may include or implement) with respect to an example or implementation means that there exists at least one example or implementation that includes or implements such a feature, and that all examples or implementations are not limited thereto. The terms “example” or “implementation” as used herein have the same meaning (e.g., the phrase “in one example” has the same meaning as “in one implementation,” and “in one or more examples” has the same meaning as “in one or more implementations”).

[0053] One or more examples can provide circuits for driving voice coil motors that have reduced offset characteristics by minimizing channel length modulation effects.

[0054] One or more examples can provide circuits for driving voice coil motors with improved power efficiency.

[0055] One or more examples can provide a maximum value for the drive current that can be increased to ensure a large driving force for the circuit driving the voice coil motor.

[0056] According to one or more examples, the circuitry used to drive the voice coil motor can minimize the channel length modulation effect, thereby reducing offset characteristics.

[0057] Based on one or more examples, power efficiency can be improved and the maximum value of the drive current can be increased, thereby providing greater drive force to the voice coil motor.

[0058] This disclosure relates to circuitry for driving a voice coil motor and a driver IC for driving a voice coil motor. The circuitry for driving a voice coil motor according to an exemplary embodiment of this disclosure is capable of variable control of the power voltage and can be included as a component of the driver IC for driving a voice coil motor.

[0059] Figure 1 This is a schematic view showing the internal configuration of the driver IC used to drive the voice coil motor.

[0060] refer to Figure 1 A driver IC 1 for driving a voice coil motor according to one or more embodiments may include a driver 10, a communication device 20, a sensor 30, a controller 40, and a power device 50. The controller 40 may be connected to each of the driver 10, the communication device 20, the sensor 30, and the power device 50.

[0061] The driver 10 can be configured to include circuitry 100 that drives a voice coil motor as described below, and can use the voice coil motor to drive a lens within the camera module under the control of the controller 40.

[0062] Furthermore, the driver 10 may include multiple channels, and the circuit 100 for driving the voice coil motor can be selectively connected to one of the multiple channels. Therefore, when the driver IC 1 for driving the voice coil motor uses multiple channels to drive the voice coil motor, the circuit 100 for driving the voice coil motor according to one or more embodiments may be connected only to the channel that utilizes variable control of electrical voltage. However, one or more examples are not limited to this.

[0063] Communication device 20 is configured to communicate with an external host. For example, communication device 20 may use communication protocols such as Inter-Integrated Circuit (I2C), Improved Inter-Integrated Circuit (I3C), Serial Peripheral Interface (SPI), or Universal Asynchronous Receiver / Transmitter (UART). However, one or more examples are not limited to these.

[0064] Sensor 30 can be configured to acquire position information of the lens in the camera module and can receive position information of the lens sensed from the Hall sensor.

[0065] The controller 40 can generate a signal for driving the lens based on the lens position information obtained by the sensor 30 and the command input from the external host via the communication device 20, thereby controlling the driver 10.

[0066] The power unit 50 can generate and supply power for the operation of each component included in the drive IC 1 used to drive the voice coil motor.

[0067] The circuit 100 for driving a voice coil motor according to an exemplary embodiment of the present disclosure may be included in the driver 10 of the driver IC 1 for driving the voice coil motor described above, or may be a component selectively connected to the driver 10. The configuration and operation of the circuit 100 for driving a voice coil motor according to one or more embodiments will be described in detail below with reference to the accompanying drawings.

[0068] refer to Figure 2 A circuit 100 for driving a voice coil motor according to one or more embodiments may include a first circuit 110 and a second circuit 120 connected to the first circuit 110, and may include a power voltage control circuit 130 connected to each of the first circuit 110 and the second circuit 120. In an example, the first circuit 110 and the second circuit 120 may be implemented as semiconductor integrated circuits and may share a power voltage VM and ground.

[0069] exist Figure 2In this context, m represents the multiplication factor; when m=N, it indicates that the current capacity is N times that when m=1.

[0070] In the first circuit 110, the first top transistor MP1 and the second top transistor MP2 can be connected by a bridge structure, and the first bottom transistor MN1 and the second bottom transistor MN2 can be connected by a bridge structure. The first circuit 110 may include a first switch SW1 and a second switch SW2, as well as a voice coil motor 111.

[0071] The second circuit 120 may include a third bottom transistor MN3 and a fourth bottom transistor MN4, as well as a current source 121, and may also include a third switch SW3 and a fourth switch SW4.

[0072] The power voltage control circuit 130 can be connected to the first circuit 110 and the second circuit 120 respectively, and can control the power voltage VM of the second circuit 120 to match the reference voltage V of the first circuit 110 through feedback operation. ref Preferably, the power voltage control circuit 130 can control the power voltage VM of the second circuit 120 to be the same as the reference voltage V of the first circuit 110. ref The same. In one or more examples, the power voltage VM of the second circuit 120 is the same as the reference voltage V of the first circuit 110. ref The same disclosure can be defined to include not only examples that are exactly the same, but also examples that are substantially the same. "Substantially the same" can mean the reference voltage V of the first circuit 110. ref The difference between the power voltage VM of the second circuit 120 and the power voltage V of the first circuit 110 is negligible, including manufacturing or measurement errors. For example, it can be interpreted as the power voltage VM of the second circuit 120 being relative to the reference voltage V of the first circuit 110. ref The difference may be ±0.1% or less, but one or more examples are not limited to this.

[0073] In the first circuit 110, the first switch SW1 and the second switch SW2 can be connected in series to connect the node between the first top transistor MP1 and the first bottom transistor MN1 and the node between the second top transistor MP2 and the second bottom transistor MN2.

[0074] The bridge structure included in the first circuit 110 can correspond to, for example, an H-bridge, a half-bridge, and a full-bridge, and can vary based on the design of the circuit 100 used to drive the voice coil motor. The H-bridge can be an effective structure for precise bidirectional driving of the voice coil motor.

[0075] The first top transistor MP1 and the second top transistor MP2 can be directly connected to the node of the power voltage VM, and can be P-type semiconductor transistors. Furthermore, the first bottom transistor MN1, the second bottom transistor MN2, the third bottom transistor MN3, and the fourth bottom transistor MN4 can be directly connected to ground, and can be N-type semiconductor transistors. However, one or more examples are not limited to this, and the N-type / P-type relationship of the transistors can be adjusted based on the circuit design. Figure 2 The N-type / P-type relationship shown is implemented in reverse.

[0076] The gate terminal of the first bottom transistor MN1 can be connected to the gate terminal and drain terminal of the fourth bottom transistor MN4. The first bottom transistor MN1 and the fourth bottom transistor MN4 can share the voltage of their gate terminals and therefore can have a current mirror relationship.

[0077] Furthermore, the gate terminal of the second bottom transistor MN2 can be connected to the gate terminal and drain terminal of the third bottom transistor MN3. The second bottom transistor MN2 and the third bottom transistor MN3 can share the voltage of their gate terminals and therefore can have a current mirror relationship.

[0078] The first top transistor MP1 and the second top transistor MP2, as well as the first bottom transistor MN1 and the second bottom transistor MN2, can perform a switching operation that controls the drive current I flowing to the voice coil motor 111. drv The direction.

[0079] In the example, when the gate voltage of the second top transistor MP2 is lower than the gate voltage of the first top transistor MP1, the drive current I flowing through the voice coil motor 111... drv It can be along by Figure 2 The path generation is indicated by the dotted lines in the diagram, and in this example, the first switch SW1 of the first circuit 110 and the fourth switch SW4 of the second circuit 120 can be operated to turn on.

[0080] Conversely, when the gate voltage of the second top transistor MP2 is higher than the gate voltage of the first top transistor MP1, the drive current I flowing through the voice coil motor 111... drv You can follow Figure 2 The solid line in the diagram indicates the path generation, and in this example, the second switch SW2 of the first circuit 110 and the third switch SW3 of the second circuit 120 can be operated to turn on.

[0081] The voice coil motor 111 can connect the node between the first top transistor MP1 and the first bottom transistor MN1 to the node between the second top transistor MP2 and the second bottom transistor MN2.

[0082] The power voltage control circuit 130 can be connected to the node between the first switch SW1 and the second switch SW2 of the first circuit 110.

[0083] The power voltage control circuit 130 can control the power voltage VM applied to one side of the first circuit 110 to be higher or lower than the input voltage V applied to one side of the second circuit 120. in The power voltage control circuit 130 of the exemplary embodiment may correspond to a DC-DC converter, and when the input voltage V... in It can operate in buck mode when the voltage is higher than the power supply voltage VM, and when the input voltage V in When the voltage is below the power supply voltage VM, it can operate in boost mode. However, one or more examples are not limited to this, and the power supply voltage control circuit 130 may operate in only one of the buck and boost modes.

[0084] refer to Figure 2 To minimize the current error caused by channel length modulation during the current mirroring process, the power voltage control circuit 130 according to one or more embodiments can control the current at node C. R voltage V CR and node B L voltage V BL Control them to be the same, and node C can be... L voltage V CL and node B R voltage V BR Controlled to be identical. In the examples, "identical voltage" can be limited to include not only examples that are exactly the same, but also examples that are substantially the same. "Substantially the same" can mean examples where the difference from the comparison voltage is within ±0.1% (including manufacturing or measurement errors), but one or more examples are not limited to this.

[0085] The following mathematical expression explains the current error reduction effect of controlling the power voltage VM according to the power voltage control circuit 130. This will be based on node C. R voltage V CR and node B L voltage V BL To explain, and can be applied to node C L voltage V CL and node B R voltage V BR .

[0086] Mathematical expression 1:

[0087] Mathematical expression 2:

[0088] In the example, due to the reference voltage V ref The voltage is controlled to be the same as the power voltage VM through the feedback operation of the power voltage control circuit 130. Mathematical expression 3:

[0089] In the example, if I drv =N I src And R src :R s =N:1, then

[0090] Mathematical expression 4:

[0091] Therefore, node C R voltage V CR Controlled to be related to node B L voltage V BL The same voltage V is applied to the third bottom transistor MN3 and the second bottom transistor MN2. DS The same applies, and therefore current errors caused by channel length modulation effects can be eliminated.

[0092] The following will be referenced Figures 9 to 1 6. A detailed configuration and various exemplary embodiments of the power voltage control circuit 130 are described. Hereinafter, a detailed description will be given of the current error, power consumption, and maximum value of the drive current I that may occur in an example where the power voltage control circuit 130 and the first switch SW1 and the second switch SW2 are omitted from the circuit 100 for driving a voice coil motor according to one or more embodiments, compared to the circuit 100 for driving a voice coil motor according to one or more embodiments. max .

[0093] Figure 3 It shows that from Figure 2 The circuit omits the power voltage control circuit and the circuits for the first and second switches of the first circuit. Figure 4 It shows in Figure 3 The equivalent circuit in the circuit when the third switch is turned on and the fourth switch is turned off.

[0094] refer to Figure 3 The size ratio of the third bottom transistor MN3 to the second bottom transistor MN2 and the size ratio of the fourth bottom transistor MN4 to the first bottom transistor MN1 can be set to 1:N respectively. In this example, the drive current I flowing through coil L... drv It should be N×Isrc However, due to channel length modulation, N×I src +N×I src ×λ×(V DS -V DS , sat The driving current I drv The current flows through coil L, which can be considered as current error.

[0095] Mathematical expression 5:

[0096] (of which KP) n μ n Cox, W: Channel width, L: Channel length, V THN : Threshold voltage, and λ: Channel length modulation coefficient).

[0097] This current error is treated as an offset voltage V by multiplying it by a certain resistor. offset Furthermore, it can be a factor that degrades characteristics (such as generating noise during actuator drive control or making precise control difficult).

[0098] exist Figure 3 In the process, when the gate voltage of the first top transistor MP1 is lower than the gate voltage of the second top transistor MP2, and the third switch SW3 is turned on and the fourth switch SW4 is turned off, the drive current I... drv Flowing in the direction of the solid line, and Figure 4 The equivalent circuit in this case is shown in the figure.

[0099] refer to Figure 4 Due to the resistance R of the voice coil motor s and the resistor R of the first top transistor MP1 MP1 Furthermore, given the size ratio of the third bottom transistor MN3 to the second bottom transistor MN2 (which is 1:N), the voltage at node B connected to the second bottom transistor MN2 and the voltage at node C connected to the third bottom transistor MN3 are different. Ultimately, due to the aforementioned channel length modulation phenomenon, the drive current I flowing through the coil L... drv Not equal to N×I src .

[0100] Mathematical Expression 6:

[0101] According to one or more embodiments, the circuit 100 for driving a voice coil motor can control the voltage V at node B via the power voltage control circuit 130. B and the voltage V at node C CTo control them to be the same, in order to reduce current error, i.e., offset voltage V offset This allows for reduced noise when driving the actuator and improved driving accuracy.

[0102] refer to Figure 5 The power efficiency improvement effect of the circuit 100 for driving a voice coil motor according to one or more embodiments will be described.

[0103] Figure 5 Compare separately Figure 2 circuit and Figure 3 A graph showing the power consumption of each component in the circuit.

[0104] The circuit 100 for driving a voice coil motor according to one or more embodiments is applied. Figure 2 In the example of the circuit, the power consumed is as follows.

[0105] Mathematical Expression 7:

[0106] Mathematical expression 8:

[0107] Mathematical Expression 9:

[0108] When the result is expressed as power consumption P in Relative to drive current I drv When plotting a curve, this can be along... Figure 5 A curve plot of triangle points (assuming R) s =20, eff=1 and V C =1).

[0109] Along Figure 5 The circular dots in the middle are used for Figure 3 The power consumption P of the circuit in In the example of the graph, since the power voltage VM is fixed at 2.8V or 3.3V and the input current and output current are the same, the power consumption P... in With drive current I drv They are in a linear proportion.

[0110] Therefore, comparison Figure 5 The two graphs show that when the circuit 100 for driving a voice coil motor according to one or more embodiments is applied (see...), it can be seen that... Figure 2 When the circuit is in operation, relative to the drive current I drv Power consumption P in This reduces power consumption, thereby improving power efficiency.

[0111] refer to Figures 6 to 8 The maximum value I of the drive current used to improve the driving force of the actuator will be described. max The effect.

[0112] Figure 6 This shows the maximum value I of the drive current when the power voltage VM is fixed at 3.3V. max A curve in the time domain t. Figure 7 This shows the maximum value I of the drive current when the power voltage VM can vary between 3.3V and 5V. max The curve graph. Figure 8 This shows the maximum value I of the drive current when the power voltage VM can vary between 0V and 5V. max The curve graph.

[0113] refer to Figure 6 ,as Figure 3 In the example of the circuit without power voltage control circuit 130, the power voltage VM can typically be set to a fixed voltage between 2.8V and 3.3V, and Figure 6 An example is shown where the power voltage VM is fixed at 3.3V.

[0114] In this example, the maximum value of the drive current I max It can be represented as follows.

[0115] Mathematical Expression 10:

[0116] Because the driving force and driving current I of the voice coil motor used in the camera actuator drv Proportional, therefore as the lens becomes heavier, a maximum value of the drive current I is expected to increase. max The method.

[0117] According to the mathematical expression 6 above, it is desirable to minimize the resistive components of the coils and switching elements in the circuit. However, to reduce the resistive components, the dimensions of the coils and switching elements, etc., should be changed. Alternatively, in an example of a circuit 100 for driving a voice coil motor according to one or more embodiments, the maximum value of the drive current I can be improved by controlling the power voltage VM. max characteristic.

[0118] exist Figure 6 In the example, since the power voltage VM is fixed at 3.3V, the maximum value of the drive current I is... max It becomes 3.3V / (R) s +R MP1,MN2 ).

[0119] exist Figure 7In one example, the circuit 100 for driving a voice coil motor according to one or more embodiments can variably control the power voltage VM between 3.3V and 5V via the power voltage control circuit 130, such that the power voltage VM changes with the drive current I. drv The value of the driving current I increases together with the increase of the value of the driving current. max It can be increased to 5V / (R) s +R MP1,MN2 ).

[0120] exist Figure 8 In the example, the circuit 100 for driving a voice coil motor according to one or more embodiments can not only be in the drive current I drv When it increases and is also driving current I drv When the voltage is reduced, the power voltage VM is changed by the power voltage control circuit 130, and in this example, the efficiency of the power consumed in the drive circuit can be improved.

[0121] In the following text, see references Figures 9 to 16E Various exemplary embodiments and detailed components of the power voltage control circuit 130 included in a circuit 100 for driving a voice coil motor according to one or more embodiments will be described.

[0122] Figure 9 This is a circuit diagram illustrating an exemplary embodiment of a power voltage control circuit included in a circuit for driving a voice coil motor.

[0123] refer to Figure 9 An exemplary circuit for driving a voice coil motor may include a power voltage control circuit 130, and the power voltage control circuit 130 may include a circuit configured to receive a reference voltage V. ref And output feedback voltage V fb Error amplifier 131.

[0124] In addition, the power voltage control circuit 130 may also include a sawtooth wave generator 132 for generating sawtooth waves and a comparison feedback voltage V. fb The sawtooth voltage V of the sawtooth wave saw Comparator 133 for generating pulse width modulation (PWM) signals.

[0125] In addition, the power voltage control circuit 130 may include at least one node N1 connected to each of the metal-oxide-semiconductor field-effect transistors (MOSFETs), diodes, and inductors.

[0126] Figure 9 The power voltage control circuit 130 can control the power voltage VM to be high or low, and can perform feedback control so that the reference current I of the current source 121... srcThe voltage VM is monitored and input to error amplifier 131, and the power voltage VM follows the reference current I. src More specifically, the following reference current I can be... src Power voltage VM and reference voltage V ref They are compared with each other, and in order to compensate for the comparison results, the feedback voltage V fb and sawtooth voltage V saw A comparison can be made to generate a pulse width modulated signal V. S1 This allows for the operation of increasing or decreasing the power voltage VM. In the example, considering the current ratio, the resistive component R of current source 121... src The resistive component R of the voice coil motor 111 s They can be set to be the same as each other, and thus, due to the reference voltage V ref The power voltage VM is controlled to be the same, therefore node C R voltage and node B L The voltage can be controlled to be the same, thereby minimizing the current error caused by channel length modulation, i.e., the offset voltage V. offset The emergence of.

[0127] Figures 10A to 10E It is shown Figure 9 The simulation results of the circuit are shown in the graph.

[0128] refer to Figure 10A and Figure 10B It can be confirmed that it is related to the drive current I. drv The magnitude of the voltage VM is proportional to the magnitude of the voltage. To perform this negative feedback operation, such as... Figure 10D As shown, the sawtooth voltage V can be... saw The feedback voltage V fb (It is the output voltage of error amplifier 131) compared to generate such Figure 10E The pulse width modulation signal V shown S1 Therefore, as Figure 10C As shown, the drive current I can be controlled in the same way. drv Sensing voltage V isens and the sensed voltage V of the power voltage VM sens .

[0129] Figure 11 It is shown Figure 9 A circuit diagram illustrating a modified example of a power voltage control circuit.

[0130] At once Figure 11 The circuit can control the increase and decrease of the power voltage VM. Figure 11 The circuit can have the same Figure 9 The circuit operates similarly. However, unlike... Figure 9 , Figure 11 The circuit is connected to only one ground, which can be more advantageous in terms of noise reduction.

[0131] refer to Figure 11 The exemplary power voltage control circuit 130 may include a coupling inductor 134.

[0132] Furthermore, the exemplary power voltage control circuit 130 may include a plurality of switching elements S1 and S2, and may operate independently in buck mode or boost mode based on the combination of switching elements S1 and S2.

[0133] Figure 12A and Figure 12B It shows when Figure 11 The input voltage V of the circuit in A view of current flow when the voltage VM is higher than the power voltage. That is, this corresponds to the method used to reduce the input voltage V. in The buck mode operation.

[0134] refer to Figure 12A When the input voltage V in When the voltage is higher than the power voltage VM, the second switching element S2 can be operated to turn on and the first switching element S1 can be operated to turn off, thereby charging and storing energy in inductors L1 and L2 and simultaneously supplying current to the load.

[0135] Next, refer to Figure 12B The second switching element S2 can be operated to be disconnected, and the first switching element S1 can be operated to be connected, so that the energy charged in the inductor can be transferred to the load.

[0136] Figure 13A and Figure 13B It shows when Figure 11 The input voltage V of the circuit in A view of current flow below the power voltage VM. In other words, this corresponds to the current flow required to increase the input voltage V. in Boost mode operation.

[0137] refer to Figure 13A and Figure 13B When the input voltage V in When the voltage is below the power supply voltage VM, the second switching element S2 can always operate in the ON position, and only the first switching element S1 can perform the ON or OFF switching operation. When the first switching element S1 operates in the ON position, energy can be charged into inductors L1 and L2, and when the first switching element S1 operates in the OFF position, the energy charged into inductors L1 and L2 can be transferred to the load.

[0138] Figures 14A to 14F It is shown Figure 11The simulation results of the circuit are shown in the graph.

[0139] refer to Figure 14A , Figure 14E and Figure 14F The first switching element S1 is based on the input voltage V. in The switching operation is always performed based on the magnitude of the power voltage VM, but the second switching element S2 only performs the switching operation in buck mode. Therefore, as... Figure 14C As shown, the drive current I can be confirmed. drv Sensing voltage V isens and the sensed voltage V of the power voltage VM sens Subject to the same control. That is to say, as Figure 14A and Figure 14B As shown in the figure, it can be confirmed that the drive current I drv The size of the voltage VM is proportionally and variably controlled.

[0140] Figure 15 It is shown Figure 9 A circuit diagram of another modified example of a power voltage control circuit.

[0141] Figure 15 The circuit is one that controls the increase of the power voltage VM (i.e., boost mode operation). In an exemplary embodiment, the power voltage control circuit 130 is activated when the maximum value I of the drive current... max This circuit can be used when the power voltage VM is limited and a relatively high power voltage VM is required. For example, when a mechanical failure occurs in a camera actuator and a large load is applied instantaneously, this circuit can be used to increase the maximum value I of the drive current. max The purpose of this disclosure is as follows, but it is not limited thereto.

[0142] refer to Figure 15 An exemplary power voltage control circuit 130 may include a switching element S1, and when the input voltage V of the power voltage control circuit 130 is... in When the voltage is below the electrical voltage VM, the switching element S1 can perform a switching operation.

[0143] Furthermore, the exemplary power voltage control circuit 130 of the exemplary embodiment may include at least one node N2 connected to an inductor and an N-type semiconductor transistor, and a diode or a P-type semiconductor transistor may also be connected to node N2.

[0144] For example, the exemplary switching element S1 can be an N-type semiconductor transistor, and the element connected to node N2 is shown as a diode, but is not limited thereto, and can also be implemented as a P-type semiconductor transistor. The exemplary power voltage control circuit 130 operates at an input voltage V. inSwitching operation is not performed under conditions higher than the power voltage VM, and in this case, efficiency degradation may occur due to the voltage drop in the diode. However, it may be advantageous in terms of power efficiency if the diode is replaced with a P-type semiconductor transistor.

[0145] Figures 16A to 16E It is shown Figure 15 The simulation results of the circuit are shown in the graph.

[0146] refer to Figure 16A and Figure 16E Only when the input voltage V in When the voltage VM is below the power supply voltage, a boost mode switching operation is performed, and thus, in boost mode, as... Figure 16C As shown, the drive current I drv Sensing voltage V isens and the sensed voltage V of the power voltage VM sens It can be controlled to be the same.

[0147] While this disclosure includes specific examples, it will be apparent upon understanding the disclosure of this application that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be understood in a descriptive sense only and not for purposes of limitation. The description of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Appropriate results may still be achieved if the described techniques are performed in a different order, and / or if components in the described system, architecture, apparatus, or circuit are combined in a different manner and / or replaced or supplemented by other components or their equivalents.

[0148] Therefore, in addition to the above disclosure and all the accompanying drawings, the scope of this disclosure also includes the claims and their equivalents, that is, all variations within the scope of the claims and their equivalents should be understood to be included in this disclosure.

Claims

1. A voice coil motor drive circuit, including: A first circuit, wherein a first top transistor, a second top transistor, a first bottom transistor, and a second bottom transistor are connected to each other via a bridge structure, and the first circuit further includes a first switch, a second switch, and a voice coil motor; The second circuit includes a third bottom transistor, a fourth bottom transistor, and a current source; as well as A power voltage control circuit is connected to both the first circuit and the second circuit, and is configured to control the power voltage of the second circuit to match the reference voltage of the first circuit based on feedback operation. The power voltage control circuit is connected to the node between the first switch and the second switch.

2. The voice coil motor drive circuit according to claim 1, wherein, The power voltage control circuit is configured to control the power voltage of the second circuit to be the same as the reference voltage of the first circuit.

3. The voice coil motor drive circuit according to claim 1, wherein, The first switch and the second switch are connected in series to connect the node between the first top transistor and the first bottom transistor and the node between the second top transistor and the second bottom transistor.

4. The voice coil motor drive circuit according to claim 1, wherein, The power voltage control circuit is a DC-DC converter.

5. The voice coil motor drive circuit according to claim 1, wherein, The power voltage control circuit is configured to control the power voltage to be greater than or less than the input voltage of the power voltage control circuit.

6. The voice coil motor drive circuit according to claim 5, wherein, The power voltage control circuit is configured to operate in buck mode when the input voltage is greater than the power voltage, and to operate in boost mode when the input voltage is less than the power voltage.

7. The voice coil motor drive circuit according to claim 1, wherein, The power voltage control circuit includes an error amplifier configured to receive the reference voltage and configured to output a feedback voltage.

8. The voice coil motor drive circuit according to claim 7, wherein, The power voltage control circuit also includes: A sawtooth wave generator, configured to generate sawtooth waves; and A comparator is configured to compare the feedback voltage with the sawtooth voltage of the sawtooth wave to generate a pulse width modulation signal.

9. The voice coil motor drive circuit according to claim 1, wherein, The power voltage control circuit includes at least one node connected to each of the MOSFET, diode, and inductor.

10. The voice coil motor drive circuit according to claim 1, wherein, The power voltage control circuit includes a coupling inductor.

11. The voice coil motor drive circuit according to claim 10, wherein, The power voltage control circuit includes multiple switching elements and is configured to operate independently in one of a buck mode and a boost mode based on a combination of the multiple switching elements.

12. The voice coil motor drive circuit according to claim 1, wherein, The power voltage control circuit includes a switching element, and the switching element is configured to perform a switching operation of turning on or off when the input voltage of the power voltage control circuit is less than the power voltage.

13. The voice coil motor drive circuit according to claim 12, wherein, The power voltage control circuit includes at least one node connected to an inductor and an N-type semiconductor transistor.

14. The voice coil motor drive circuit according to claim 13, wherein, One of the diode and the P-type semiconductor transistor is also connected to the at least one node.

15. The voice coil motor drive circuit according to claim 1, wherein, The voice coil motor is configured to connect the node between the first top transistor and the first bottom transistor to the node between the second top transistor and the second bottom transistor.

16. The voice coil motor drive circuit according to claim 1, wherein, The first top transistor and the second top transistor are directly connected to the node of the power voltage, and The first bottom transistor, the second bottom transistor, the third bottom transistor, and the fourth bottom transistor are each directly connected to ground.

17. The voice coil motor drive circuit according to claim 1, wherein, The first top transistor and the second top transistor are P-type semiconductor transistors, and The first bottom transistor, the second bottom transistor, the third bottom transistor, and the fourth bottom transistor are all N-type semiconductor transistors.

18. The voice coil motor drive circuit according to claim 17, wherein, The gate terminal of the first bottom transistor is connected to the gate terminal and the drain terminal of the fourth bottom transistor, and The gate terminal of the second bottom transistor is connected to the gate terminal and the drain terminal of the third bottom transistor.

19. A driver integrated circuit configured to drive a voice coil motor, said driver integrated circuit comprising: The driver includes the voice coil motor drive circuit according to any one of claims 1 to 18; A communication device configured to communicate with an external host; A sensor configured to acquire position information of the lens in the camera module; The controller is configured to generate signals for driving the lens to control the driver based on the position information of the lens and commands input from the external host; as well as An electrical device configured to generate electricity for performing operations.

20. The driver integrated circuit according to claim 19, wherein, The driver also includes multiple channels, and the voice coil motor drive circuit is selectively connected to any one of the multiple channels.

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