Camera Focus Driving Circuit and Method

Abstract

The present invention belongs to the technical field of camera focusing, and discloses a camera focusing drive circuit and method. The circuit includes a main control module, a focusing drive module, and a zoom drive module; the main control module is configured to output a focusing PWM wave and a focusing voltage threshold to the focusing drive module, and is further configured to output a zoom PWM wave and a zoom voltage threshold to the zoom drive module; the focusing drive module is configured to drive a focusing voice coil motor according to the focusing PWM wave and the focusing voltage threshold, and change the rotation direction and driving force of the focusing voice coil motor; the zoom drive module is configured to drive a zoom voice coil motor according to the zoom PWM wave and the zoom voltage threshold, and change the rotation direction and driving force of the zoom voice coil motor. The present invention uses a voice coil motor for camera focusing and sets a position detection function, which improves the focusing accuracy while ensuring the focusing speed and large stroke.

Description

Technical Field

[0001] The invention relates to the field of camera focusing, and particularly to a camera focusing drive circuit and a camera. Background Art

[0002] At present, the zoom camera module uses a stepping motor or a DC motor for zoom drive, with a long zoom time and a slow speed. The transmission mechanism is that the motor rotor drives a series of mechanical transmission parts through the motor shaft. In this process, there are possibilities such as gaps, elastic deformations, and frictional damping in the motor, resulting in a reduction and loss of the rigidity and response characteristics of the device.

[0003] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The main purpose of the present invention is to provide a camera focusing drive circuit and method, aiming to solve the technical problems of slow response and inaccurate positioning in the zooming process of a stepping motor or a DC motor in the prior art.

[0005] To achieve the above object, the present invention provides a camera focusing drive circuit, which includes: a main control module, a focus drive module and a zoom drive module respectively connected to the main control module, the focus drive module is connected to a focus voice coil motor, and the zoom drive module is connected to a zoom voice coil motor;

[0006] The main control module is configured to output a focus PWM wave and a focus voltage threshold to the focus drive module, so that the focus drive module changes the rotation direction and driving force of the focus voice coil motor;

[0007] The main control module is further configured to output a zoom PWM wave and a zoom voltage threshold to the zoom drive module, so that the zoom drive module changes the rotation direction and driving force of the zoom voice coil motor;

[0008] The focus drive module is configured to drive the focus voice coil motor according to the focus PWM wave and the focus voltage threshold, change the rotation direction and driving force of the focus voice coil motor, so that the camera lens completes focusing;

[0009] The zoom drive module is configured to drive the zoom voice coil motor according to the zoom PWM wave and the zoom voltage threshold, change the rotation direction and driving force of the zoom voice coil motor, so that the camera lens completes zooming.

[0010] Optionally, the focus driving module includes: a focus driving unit, a focus position detecting unit, and a focus limit detecting unit; wherein, the focus driving unit, the focus position detecting unit, and the focus limit detecting unit are respectively connected to the main control module, and the focus driving unit is further connected to a focus voice coil motor;

[0011] The focus driving unit is configured to output a first focus control signal and a second focus control signal to the focus voice coil motor according to the focus PWM wave and the focus voltage threshold, so as to change the rotation direction and driving force of the focus voice coil motor;

[0012] The focus position detecting unit is configured to measure the magnetic pole strength at the focus voice coil motor, and send a first focus voltage signal and a second focus voltage signal to the main control module, so that the main control module calculates the displacement of the focus voice coil motor;

[0013] The focus limit detecting unit is configured to detect the limit point of the focus voice coil motor, so that the main control module performs error correction according to the displacement of the focus voice coil motor and the limit point of the focus voice coil motor during the stroke of the focus voice coil motor, obtains a focus error correction result, and updates the focus PWM wave according to the focus error correction result.

[0014] Optionally, the main control module includes: a first focus signal output terminal, a second focus signal output terminal, a third focus signal output terminal, and a first digital-to-analog signal output terminal; wherein, the first focus signal output terminal, the second focus signal output terminal, and the third focus signal output terminal are connected to the focus driving unit, and the first digital-to-analog signal output terminal is connected to the focus driving unit;

[0015] The main control module is configured to send a first focus PWM wave to the focus driving unit through the first focus signal output terminal;

[0016] The main control module is further configured to send a second focus PWM wave to the focus driving unit through the second focus signal output terminal;

[0017] The main control module is further configured to send a focus selection signal to the focus driving unit through the third focus signal output terminal, so that the focus driving unit selects a focus PWM wave from the first focus PWM wave and the second focus PWM wave;

[0018] The main control module is further configured to output a focus voltage threshold to the focus driving unit through the first digital-to-analog signal output terminal, so as to change the driving force of the focus voice coil motor through the focus driving unit.

[0019] Optionally, the main control module further includes: a first analog-to-digital signal input terminal and a second analog-to-digital signal input terminal, which are connected to the focus position detection unit;

[0020] The main control module is configured to receive, through the first analog-to-digital signal input terminal, a first focus voltage signal transmitted by the focus position detection unit;

[0021] The main control module is further configured to receive, through the second analog-to-digital signal input terminal, a second focus voltage signal transmitted by the focus position detection unit;

[0022] The main control module is further configured to calculate the displacement of the focus voice coil motor according to the first focus voltage signal and the second focus voltage signal.

[0023] Optionally, the zoom driving module includes: a zoom driving unit, a zoom position detection unit, and a zoom limit detection unit; wherein, the zoom driving unit, the zoom position detection unit, and the zoom limit detection unit are respectively connected to the main control module, and the zoom driving unit is further connected to a zoom voice coil motor;

[0024] The zoom driving unit is configured to output a first zoom control signal and a second zoom control signal to the zoom voice coil motor according to the zoom PWM wave and the zoom voltage threshold, so as to change the rotation direction and driving force of the zoom voice coil motor;

[0025] The zoom position detection unit is configured to measure the magnetic pole strength at the zoom voice coil motor, and send a first zoom voltage signal and a second zoom voltage signal to the main control module, so that the main control module calculates the displacement of the zoom voice coil motor;

[0026] The zoom limit detection unit is configured to detect the limit point of the zoom voice coil motor, so that the main control module performs error correction according to the displacement of the zoom voice coil motor and the limit point of the zoom voice coil motor during the stroke of the zoom voice coil motor, obtains a zoom error correction result, and updates the zoom PWM wave according to the zoom error correction result.

[0027] Optionally, the main control module includes: a first zoom signal output terminal, a second zoom signal output terminal, a third zoom signal output terminal, and a second digital-to-analog signal output terminal; wherein, the first zoom signal output terminal, the second zoom signal output terminal, and the third zoom signal output terminal are connected to the zoom driving unit, and the second digital-to-analog signal output terminal is connected to the zoom driving unit;

[0028] The main control module is configured to send a first zoom PWM wave to the zoom driving unit through the first zoom signal output terminal;

[0029] The main control module is further configured to send a second zoom PWM wave to the zoom driving unit through the second zoom signal output terminal;

[0030] The main control module is further configured to send a zoom selection signal to the zoom driving unit through the third zoom signal output terminal, so that the zoom driving unit selects a zoom PWM wave from the first zoom PWM wave and the second zoom PWM wave;

[0031] The main control module is further configured to output a zoom voltage threshold to the zoom driving unit through the second digital-to-analog signal output terminal, so as to change the driving force of the zoom voice coil motor through the zoom driving unit.

[0032] Optionally, the main control module further includes: a third analog-to-digital signal input terminal and a fourth analog-to-digital signal input terminal, and the third analog-to-digital signal input terminal and the fourth analog-to-digital signal input terminal are connected to the zoom position detection unit;

[0033] The main control module is configured to receive a first zoom voltage signal transmitted by the zoom position detection unit through the third analog-to-digital signal input terminal;

[0034] The main control module is further configured to receive a second zoom voltage signal transmitted by the zoom position detection unit through the fourth analog-to-digital signal input terminal;

[0035] The main control module is further configured to calculate the displacement of the zoom voice coil motor according to the first zoom voltage signal and the second zoom voltage signal.

[0036] Optionally, the camera focusing drive circuit further includes a debugging module and a serial port module respectively connected to the main control module.

[0037] Optionally, the camera focusing drive circuit further includes: a power supply module, the power supply module is connected to the main control module and the focusing drive unit, and the power supply module is further connected to the zoom drive unit;

[0038] The power supply module is configured to supply electrical energy to each module.

[0039] In addition, to achieve the above object, the present invention further provides a camera focusing drive method, the camera focusing drive method is applied to the camera focusing drive circuit as described above, the camera focusing drive circuit includes: a main control module, a focusing drive module and a zoom drive module respectively connected to the main control module, the focusing drive module is connected to a focusing voice coil motor, the zoom drive module is connected to a zoom voice coil motor, and the camera focusing drive method includes:

[0040] The main control module outputs a focusing PWM wave and a focusing voltage threshold to the focusing drive module, and outputs a zooming PWM wave and a zooming voltage threshold to the zooming drive module;

[0041] The focusing drive module drives a focusing voice coil motor according to the focusing PWM wave and the focusing voltage threshold, changing the rotation direction and driving force of the focusing voice coil motor, so that the camera lens completes focusing;

[0042] The zooming drive module drives a zooming voice coil motor according to the zooming PWM wave and the zooming voltage threshold, changing the rotation direction and driving force of the zooming voice coil motor, so that the camera lens completes zooming.

[0043] In the present invention, by providing a camera focusing drive circuit, the camera focusing drive circuit includes: a main control module, a focusing drive module and a zooming drive module respectively connected to the main control module, the focusing drive module is connected to a focusing voice coil motor, and the zooming drive module is connected to a zooming voice coil motor; the main control module is used to output a focusing PWM wave and a focusing voltage threshold to the focusing drive module, so that the focusing drive module changes the rotation direction and driving force of the focusing voice coil motor; the main control module is further used to output a zooming PWM wave and a zooming voltage threshold to the zooming drive module, so that the zooming drive module changes the rotation direction and driving force of the zooming voice coil motor; the focusing drive module is used to drive a focusing voice coil motor according to the focusing PWM wave and the focusing voltage threshold, changing the rotation direction and driving force of the focusing voice coil motor, so that the camera lens completes focusing; the zooming drive module is used to drive a zooming voice coil motor according to the zooming PWM wave and the zooming voltage threshold, changing the rotation direction and driving force of the zooming voice coil motor, so that the camera lens completes zooming. By using a voice coil motor for camera focusing and setting a position detection function, the focusing accuracy is improved while ensuring the focusing speed and large stroke. Description of the Drawings

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0045] Figure 1 It is a schematic diagram of the function modules of an embodiment of the camera focusing drive circuit of the present invention;

[0046] Figure 2 It is a schematic diagram of the circuit modules of an embodiment of the camera focusing drive circuit of the present invention;

[0047] Figure 3 This is a schematic flowchart of the first embodiment of the camera focusing drive method of the present invention.

[0048] Explanation of the reference numerals in the drawings:

[0049] Label Name Label Name 100 Main control module ADC12_IN4 Second analog-to-digital signal input terminal 200 Focus drive module 301 Zoom drive unit 300 Zoom drive module 302 Zoom position detection unit 400 Focus voice coil motor 303 Zoom limit detection unit 500 Zoom voice coil motor TIM2_CH1 First zoom signal output terminal 201 Focus drive unit TIM2_CH2 Second zoom signal output terminal 202 Focus position detection unit TIM2_CH3 Third zoom signal output terminal 203 Focus limit detection unit DAC_OUT2 Second digital-to-analog signal output terminal TIM4_CH1 First focus signal output terminal ADC1_IN15 Third analog-to-digital signal input terminal TIM4_CH2 Second focus signal output terminal ADC1_IN12 Fourth analog-to-digital signal input terminal TIM4_CH3 Third focus signal output terminal 600 Debug module DAC_OUT1 First digital-to-analog signal output terminal 700 Serial port module ADC12_IN3 First analog-to-digital signal input terminal 800 Power supply module

[0050] The implementation, functional features and advantages of the object of the present invention will be further described in conjunction with the embodiments with reference to the drawings. Detailed implementation manners

[0051] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0052] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0053] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0054] In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0055] Reference Figure 1 , Figure 1 This is a schematic diagram of the functional modules of an embodiment of the camera focusing drive circuit of the present invention;

[0056] The camera focusing drive circuit includes: a main control module 100, a focusing drive module 200 and a zoom drive module 300 respectively connected to the main control module 100. The focusing drive module 200 is connected to a focusing voice coil motor 400, and the zoom drive module 300 is connected to a zoom voice coil motor 500;

[0057] The main control module 100 is configured to output a focusing PWM wave and a focusing voltage threshold to the focusing drive module 200, so that the focusing drive module 200 changes the rotation direction and driving force of the focusing voice coil motor 400;

[0058] It can be understood that the main control module 100 is a microprocessor including at least an internal timer, a digital-to-analog converter, and an analog-to-digital converter. For example: STM32 single-chip microcomputer. The internal timer can generate a focusing PWM wave that meets the requirements and can adjust the duty cycle of the focusing PWM wave to achieve a better driving effect; the digital-to-analog converter can send the focusing voltage threshold to change the driving force of the focusing voice coil motor 400. In specific implementation, the main control module 100 can be selected according to specific situations, and this embodiment does not limit this.

[0059] It should be noted that the focusing voice coil motor 400 is a voice coil motor used to complete the focusing action; this voice coil motor has the characteristics of simple structure, no need to add a device to convert the rotational motion into a linear motion, high positioning accuracy, can achieve direct drive and eliminate various errors caused by intermediate links, fast response speed, high sensitivity, and can follow well, etc.; in this embodiment, the focusing voice coil motor 400 is controlled by a microcomputer, greatly improving the positioning accuracy of the entire system.

[0060] The main control module 100 is further configured to output a zooming PWM wave and a zooming voltage threshold to the zooming drive module 300, so that the zooming drive module 300 changes the rotation direction and driving force of the zooming voice coil motor 500;

[0061] It should be noted that the zooming voice coil motor 500 is a voice coil motor used to complete the focusing action; this voice coil motor has the characteristics of simple structure, no need to add a device to convert the rotational motion into a linear motion, high positioning accuracy, can achieve direct drive and eliminate various errors caused by intermediate links, fast response speed, high sensitivity, and can follow well, etc.; in this embodiment, the focusing voice coil motor 400 is controlled by a microcomputer, greatly improving the positioning accuracy of the entire system.

[0062] The focusing drive module 200 is configured to drive the focusing voice coil motor 400 according to the focusing PWM wave and the focusing voltage threshold, change the rotation direction and driving force of the focusing voice coil motor 400, so that the camera lens completes focusing;

[0063] It can be understood that the focusing drive module 200 at least includes a focusing voice coil motor 400 driver, and this focusing voice coil motor 400 driver is a voice coil motor driver used to drive the focusing voice coil motor 400 to drive the camera lens to focus.

[0064] The zoom driving module 300 is configured to drive the zoom voice coil motor 500 according to the zoom PWM wave and the zoom voltage threshold, and change the rotation direction and driving force of the zoom voice coil motor 500, so that the camera lens completes zooming.

[0065] It can be understood that the zoom driving module 200 at least includes a zoom voice coil motor driver, which is a voice coil motor driver for driving the zoom voice coil motor 500 to drive the camera lens to zoom.

[0066] This embodiment provides a camera focusing driving circuit, which includes: a main control module 100, a focusing driving module 200 and a zoom driving module 300 respectively connected to the main control module 100, the focusing driving module 200 is connected to a focusing voice coil motor 400, and the zoom driving module 300 is connected to a zoom voice coil motor 500; the main control module 100 is configured to output a focusing PWM wave and a focusing voltage threshold to the focusing driving module 200, so that the focusing driving module 200 changes the rotation direction and driving force of the focusing voice coil motor 400; the main control module 100 is further configured to output a zoom PWM wave and a zoom voltage threshold to the zoom driving module 300, so that the zoom driving module 300 changes the rotation direction and driving force of the zoom voice coil motor 500; the focusing driving module 200 is configured to drive the focusing voice coil motor 400 according to the focusing PWM wave and the focusing voltage threshold, and change the rotation direction and driving force of the focusing voice coil motor 400, so that the camera lens completes focusing; the zoom driving module 300 is configured to drive the zoom voice coil motor 500 according to the zoom PWM wave and the zoom voltage threshold, and change the rotation direction and driving force of the zoom voice coil motor 500, so that the camera lens completes zooming. This circuit drives the camera to focus by using a voice coil motor, and uses PWM waves and voltage thresholds to change the rotation direction and driving force of the voice coil motor, improving the response speed and focusing accuracy of the camera focusing.

[0067] Further, referring to Figure 2 , Figure 2 is a schematic circuit structure diagram of an embodiment of the camera focusing driving circuit of the present invention;

[0068] The focusing driving module 200 includes: a focusing driving unit 201, a focusing position detection unit 202 and a focusing limit detection unit 203; wherein, the focusing driving unit 201, the focusing position detection unit 202 and the focusing limit detection unit 203 are respectively connected to the main control module 100, and the focusing driving unit 201 is further connected to the focusing voice coil motor 400;

[0069] The focus driving unit 201 is configured to output a first focus control signal and a second focus control signal to the focus voice coil motor 400 according to the focus PWM wave and the focus voltage threshold, so as to change the rotation direction and driving force of the focus voice coil motor 400;

[0070] It should be noted that the first focus control signal is a voltage signal generated according to the duty cycle of the focus PWM wave, which can change the rotation direction and speed of the focus voice coil motor 400. Further, the second focus control signal is a current signal generated according to the focus voltage threshold, which can change the driving force of the focus voice coil motor 400, so that the focus voice coil motor 400 drives the camera lens to rotate to the target position.

[0071] The focus position detection unit 202 is configured to measure the magnetic pole strength at the focus voice coil motor 400, and send a first focus voltage signal and a second focus voltage signal to the main control module 100, so that the main control module 100 calculates the displacement of the focus voice coil motor 400;

[0072] It should be noted that the focus position detection unit 202 at least includes a focus giant magnetoresistive detector, which detects the magnetic pole strength through a Wheatstone bridge structure and then calculates the displacement through a voltage signal.

[0073] The focus limit detection unit 203 is configured to detect the limit points of the focus voice coil motor 400, so that the main control module 100 performs error correction according to the displacement of the focus voice coil motor 400 and the limit points of the focus voice coil motor 400 during the stroke of the focus voice coil motor 400, obtains a focus error correction result, and updates the focus PWM wave according to the focus error correction result.

[0074] It should be noted that the focus limit detection unit 203 detects the limit points of the focus voice coil motor 400 through an optoelectronic coding switch.

[0075] Further, continue to refer to Figure 2 , the main control module 100 includes: a first focus signal output terminal TIM4_CH1, a second focus signal output terminal TIM4_CH3, a third focus signal output terminal TIM4_CH3, and a first digital-to-analog signal output terminal DAC_OUT1; wherein, the first focus signal output terminal TIM4_CH1, the second focus signal output terminal TIM4_CH3, and the third focus signal output terminal TIM4_CH3 are connected to the focus driving unit 201, and the first digital-to-analog signal output terminal DAC_OUT1 is connected to the focus driving unit 201;

[0076] The main control module 100 is configured to send a first focusing PWM wave to the focusing driving unit 201 through the first focusing signal output terminal TIM4_CH1;

[0077] In this embodiment, the first focusing signal output terminal TIM4_CH1 is an output pin of the STM32 single-chip microcomputer, and this pin corresponds to an internal timer of the STM32 single-chip microcomputer.

[0078] The main control module 100 is further configured to send a second focusing PWM wave to the focusing driving unit 201 through the second focusing signal output terminal TIM4_CH3;

[0079] In this embodiment, the second focusing signal output terminal TIM4_CH3 is an output pin of the STM32 single-chip microcomputer, and this pin corresponds to the same internal timer as the first focusing signal output terminal TIM4_CH1.

[0080] It can be understood that since the first focusing PWM wave and the second focusing PWM wave are pulse modulation signals generated by the same timer, the first focusing PWM wave and the second focusing PWM wave have the same frequency and different duty cycles.

[0081] The main control module 100 is further configured to send a focusing selection signal to the focusing driving unit 201 through the third focusing signal output terminal TIM4_CH3, so that the focusing driving unit 201 selects a focusing PWM wave from the first focusing PWM wave and the second focusing PWM wave;

[0082] In this embodiment, the third focusing signal output terminal TIM4_CH3 is an output pin of the STM32 single-chip microcomputer, and this pin corresponds to the same internal timer as the first focusing signal output terminal TIM4_CH1 and the second focusing signal output terminal TIM4_CH3.

[0083] The main control module 100 is further configured to output a focusing voltage threshold to the focusing driving unit 201 through the first digital-to-analog signal output terminal DAC_OUT1, so as to change the driving force of the focusing voice coil motor 400 through the focusing driving unit 201.

[0084] In this embodiment, the first digital-to-analog signal output terminal DAC_OUT1 is an output pin of the STM32 single-chip microcomputer, and this pin corresponds to a digital-to-analog converter inside the single-chip microcomputer.

[0085] Further, continue to refer to Figure 2, the main control module 100 further includes: a first analog-to-digital signal input terminal ADC12_IN3 and a second analog-to-digital signal input terminal ADC12_IN4, and the first analog-to-digital signal input terminal ADC12_IN3 and the second analog-to-digital signal input terminal ADC12_IN4 are connected to the focus position detection unit 202;

[0086] The main control module 100 is configured to receive a first focus voltage signal transmitted by the focus position detection unit 202 through the first analog-to-digital signal input terminal ADC12_IN3;

[0087] In this embodiment, the first analog-to-digital signal input terminal is an input pin of an STM32 single-chip microcomputer, and this pin corresponds to an analog-to-digital converter inside the single-chip microcomputer.

[0088] It should be noted that the first focus voltage signal is a sine signal generated by a Wheatstone bridge in the focus giant magnetoresistive detector according to the change of the magnetic field.

[0089] The main control module 100 is further configured to receive a second focus voltage signal transmitted by the focus position detection unit 202 through the second analog-to-digital signal input terminal ADC12_IN4;

[0090] In this embodiment, the first analog-to-digital signal input terminal is an input pin of an STM32 single-chip microcomputer, and this pin corresponds to the same analog-to-digital converter as the second analog-to-digital signal input terminal.

[0091] It should be noted that the second focus voltage signal is a cosine signal generated by a Wheatstone bridge in the focus giant magnetoresistive detector according to the change of the magnetic field.

[0092] The main control module 100 is further configured to calculate the displacement of the focus voice coil motor 400 according to the first focus voltage signal and the second focus voltage signal.

[0093] It should be noted that by calculating the arctangent values of the first focus voltage signal and the second focus voltage signal and judging the positive and negative values of the two signals, the displacement of the focus voice coil motor 400 can be calculated.

[0094] Further, continue to refer to Figure 2 , the zoom driving module 300 includes: a zoom driving unit 301, a zoom position detection unit 302, and a zoom position detection unit 303; wherein, the zoom driving unit 301, the zoom position detection unit 302, and the zoom position detection unit 303 are respectively connected to the main control module 100, and the zoom driving unit 301 is further connected to a zoom voice coil motor 500;

[0095] The zoom driving unit 301 is configured to output a first zoom control signal and a second zoom control signal to the zoom voice coil motor 500 according to the zoom PWM wave and the zoom voltage threshold, so as to change the rotation direction and driving force of the zoom voice coil motor 500;

[0096] It should be noted that the first zoom control signal is a voltage signal generated according to the duty cycle of the zoom PWM wave, which can change the rotation direction and speed of the zoom voice coil motor 500. Further, the second zoom control signal is a current signal generated according to the zoom voltage threshold, which can change the driving force of the zoom voice coil motor 500, so that the zoom voice coil motor 500 drives the camera lens to rotate to the target position.

[0097] The zoom position detection unit 302 is configured to measure the magnetic pole strength at the zoom voice coil motor 500, and send a first zoom voltage signal and a second zoom voltage signal to the main control module 100, so that the main control module 100 calculates the displacement of the zoom voice coil motor 500;

[0098] It should be noted that the zoom position detection unit 302 at least includes a zoom giant magnetoresistive detector, which detects the magnetic pole strength through a Wheatstone bridge structure and then calculates the displacement through a voltage signal.

[0099] The zoom position detection unit 303 is configured to detect the limit point of the zoom voice coil motor 500, so that the main control module 100 performs error correction according to the displacement of the zoom voice coil motor 500 and the limit point of the zoom voice coil motor 500 during the stroke of the zoom voice coil motor 500, obtains a zoom error correction result, and updates the zoom PWM wave according to the zoom error correction result.

[0100] It should be noted that the zoom position detection unit 303 detects the limit point of the zoom voice coil motor 500 through an optoelectronic coding switch.

[0101] Further, continue to refer to Figure 2 , the main control module 100 includes: a first zoom signal output terminal TIM2_CH1, a second zoom signal output terminal TIM2_CH2, a third zoom signal output terminal TIM2_CH3, and a second digital-to-analog signal output terminal DAC_OUT2; wherein, the first zoom signal output terminal TIM2_CH1, the second zoom signal output terminal TIM2_CH2, and the third zoom signal output terminal TIM2_CH3 are connected to the zoom driving unit 301, and the second digital-to-analog signal output terminal DAC_OUT2 is connected to the zoom driving unit 301;

[0102] The main control module 100 is configured to send a first zoom PWM wave to the zoom driving unit 301 through the first zoom signal output terminal TIM2_CH1;

[0103] In this embodiment, the first zoom signal output terminal TIM2_CH1 is an output pin of the STM32 single-chip microcomputer, and this pin corresponds to another internal timer of the STM32 single-chip microcomputer.

[0104] The main control module 100 is further configured to send a second zoom PWM wave to the zoom driving unit 301 through the second zoom signal output terminal TIM2_CH2;

[0105] In this embodiment, the second zoom signal output terminal TIM2_CH2 is an output pin of the STM32 single-chip microcomputer, and this pin corresponds to the same internal timer as the first zoom signal output terminal TIM2_CH1.

[0106] It can be understood that since the first zoom PWM wave and the second zoom PWM wave are pulse modulation signals generated by the same timer, the first zoom PWM wave and the second zoom PWM wave have the same frequency and different duty cycles.

[0107] The main control module 100 is further configured to send a zoom selection signal to the zoom driving unit 301 through the third zoom signal output terminal TIM2_CH3, so that the zoom driving unit 301 selects a zoom PWM wave from the first zoom PWM wave and the second zoom PWM wave;

[0108] In this embodiment, the third zoom signal output terminal TIM2_CH3 is an output pin of the STM32 single-chip microcomputer, and this pin corresponds to the same internal timer as the first zoom signal output terminal TIM2_CH1 and the second zoom signal output terminal TIM2_CH2.

[0109] The main control module 100 is further configured to output a zoom voltage threshold to the zoom driving unit 301 through the second digital-to-analog signal output terminal DAC_OUT2, so as to change the driving force of the zoom voice coil motor 500 through the zoom driving unit 301.

[0110] In this embodiment, the first digital-to-analog signal output terminal DAC_OUT1 is an output pin of the STM32 single-chip microcomputer, and this pin corresponds to a digital-to-analog converter inside the single-chip microcomputer.

[0111] Further, continue to refer to Figure 2, the main control module 100 further includes: a third analog-to-digital signal input terminal ADC1_IN15 and a fourth analog-to-digital signal input terminal ADC1_IN12, and the third analog-to-digital signal input terminal ADC1_IN15 and the fourth analog-to-digital signal input terminal ADC1_IN12 are connected to the zoom position detection unit 302;

[0112] The main control module 100 is configured to receive a first zoom voltage signal transmitted by the zoom position detection unit 302 through the third analog-to-digital signal input terminal ADC1_IN15;

[0113] In this embodiment, the third analog-to-digital signal input terminal ADC1_IN15 is an input pin of the STM32 single-chip microcomputer, and this pin corresponds to another analog-to-digital converter inside the single-chip microcomputer.

[0114] It should be noted that the first zoom voltage signal is a sinusoidal signal generated by a Wheatstone bridge in the zoom giant magnetoresistive detector according to the change of the magnetic field.

[0115] The main control module 100 is further configured to receive a second zoom voltage signal transmitted by the zoom position detection unit 302 through the fourth analog-to-digital signal input terminal ADC1_IN12;

[0116] In this embodiment, the fourth analog-to-digital signal input terminal ADC1_IN12 is an input pin of the STM32 single-chip microcomputer, and this pin corresponds to the same analog-to-digital converter as the third analog-to-digital signal input terminal ADC1_IN15.

[0117] It should be noted that the second zoom voltage signal is a cosine signal generated by a Wheatstone bridge in the zoom giant magnetoresistive detector according to the change of the magnetic field.

[0118] The main control module 100 is further configured to calculate the displacement of the zoom voice coil motor 500 according to the first zoom voltage signal and the second zoom voltage signal.

[0119] It should be noted that by calculating the arctangent values of the first zoom voltage signal and the second zoom voltage signal and judging the positive and negative values of the two signals, the displacement of the zoom voice coil motor 500 can be calculated.

[0120] Further, continue to refer to Figure 2 , the camera focusing drive circuit further includes a debugging module 600 and a serial port module 700 respectively connected to the main control module 100.

[0121] It is easy to understand that the debugging module 600 is used to assist in error correction, and the serial port module 700 is used to implement debugging and communication functions.

[0122] Further, the camera focusing drive circuit further includes: a power supply module 800, the power supply module 800 is connected to the main control module 100 and the focusing drive unit 201, and the power supply module 800 is further connected to the zoom drive unit 301;

[0123] The power supply module 800 is used to provide electrical energy for each module.

[0124] In this embodiment, by using the internal timer of the STM32 single-chip microcomputer to generate two focusing PWM waves with the same frequency and different duty cycles and two zoom PWM waves with the same frequency and different duty cycles, and outputting corresponding selection signals, the rotation direction of the corresponding voice coil motor is accurately changed, and two voltage thresholds are generated to accurately and quickly change the driving force of the corresponding voice coil motor. At the same time, in this embodiment, by introducing position detection and limit detection, the PWM wave can be adjusted in real time according to the current working state of the voice coil motor, further improving the focusing accuracy of the camera.

[0125] Figure 3 It is a schematic flowchart of the first embodiment of the camera focusing drive method of the present invention.

[0126] Reference Figure 3 , the camera focusing drive method is applied to the camera focusing drive circuit as described above. The camera focusing drive circuit includes: a main control module, a focusing drive module and a zoom drive module respectively connected to the main control module. The focusing drive module is connected to a focusing voice coil motor, and the zoom drive module is connected to a zoom voice coil motor. The camera focusing drive method includes:

[0127] Step S10: The main control module outputs a focusing PWM wave and a focusing voltage threshold to the focusing drive module, and outputs a zoom PWM wave and a zoom voltage threshold to the zoom drive module.

[0128] It can be understood that the main control module is a microprocessor including at least an internal timer, a digital-to-analog converter and an analog-to-digital converter, for example: an STM32 single-chip microcomputer. This internal timer can generate a focusing PWM wave that meets the requirements and can adjust the duty cycle of the focusing PWM wave to achieve a better driving effect; this digital-to-analog converter can send a focusing voltage threshold to change the driving force of the focusing voice coil motor. In specific implementation, the main control module can be selected according to specific circumstances, and this embodiment does not limit this.

[0129] It should be noted that the focusing voice coil motor is a voice coil motor used to complete the focusing action, and the zoom voice coil motor is a voice coil motor used to complete the zoom action; the voice coil motor has the characteristics of simple structure, no need to add a device to convert the rotational motion into a linear motion, high positioning accuracy, can achieve direct drive and eliminate various errors caused by intermediate links, fast response speed, high sensitivity, and can follow well; in this embodiment, the focusing voice coil motor is controlled by a microcomputer, which greatly improves the positioning accuracy of the entire system.

[0130] Step S20: The focusing drive module drives the focusing voice coil motor according to the focusing PWM wave and the focusing voltage threshold, and changes the rotation direction and driving force of the focusing voice coil motor, so that the camera lens completes focusing.

[0131] It can be understood that the focusing drive module at least includes a focusing voice coil motor driver, and this focusing voice coil motor driver is a voice coil motor driver used to drive the focusing voice coil motor to drive the camera lens to focus.

[0132] Step S30: The zoom drive module drives the zoom voice coil motor according to the zoom PWM wave and the zoom voltage threshold, and changes the rotation direction and driving force of the zoom voice coil motor, so that the camera lens completes zooming.

[0133] It can be understood that the zoom drive module at least includes a zoom voice coil motor driver, and this focusing voice coil motor driver is a voice coil motor driver used to drive the zoom voice coil motor to drive the camera lens to zoom.

[0134] In this embodiment, by using a voice coil motor to drive the camera to focus, and using the PWM wave and voltage threshold to change the rotation direction and driving force of the voice coil motor, the response speed of the camera focusing is improved and the focusing accuracy of the camera focusing is improved.

[0135] It should be understood that the above is only for illustrative purposes and does not constitute any limitation to the technical solution of the present invention. In specific applications, those skilled in the art can set according to needs, and the present invention does not limit this.

[0136] It should be noted that the above-described work process is only illustrative and does not limit the protection scope of the present invention. In actual applications, those skilled in the art can select some or all of them according to actual needs to achieve the purpose of the solution of this embodiment, and there is no limitation here.

[0137] In addition, for the technical details not described in detail in this embodiment, reference can be made to the camera focusing drive circuit provided in any embodiment of the present invention, which will not be elaborated here.

[0138] In addition, it should be noted that in this text, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or system. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or system including such an element.

[0139] The serial numbers of the above embodiments of the present invention are only for description and do not represent the superiority or inferiority of the embodiments.

[0140] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-described embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as a read-only memory (ROM) / RAM, magnetic disk, optical disc), and includes several instructions for causing a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0141] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made by using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A camera focusing drive circuit, characterized in that, the camera focusing drive circuit includes: a main control module, a focusing drive module and a zoom drive module respectively connected to the main control module, the focusing drive module is connected to a focusing voice coil motor, and the zoom drive module is connected to a zoom voice coil motor; the main control module is configured to output a focusing PWM wave and a focusing voltage threshold to the focusing drive module, so as to enable the focusing drive module to change the rotation direction and driving force of the focusing voice coil motor; the main control module is further configured to output a zoom PWM wave and a zoom voltage threshold to the zoom drive module, so as to enable the zoom drive module to change the rotation direction and driving force of the zoom voice coil motor; the focusing drive module is configured to drive the focusing voice coil motor according to the focusing PWM wave and the focusing voltage threshold, and change the rotation direction and driving force of the focusing voice coil motor, so that the camera lens completes focusing; the zoom drive module is configured to drive the zoom voice coil motor according to the zoom PWM wave and the zoom voltage threshold, and change the rotation direction and driving force of the zoom voice coil motor, so that the camera lens completes zooming; the focusing drive module includes: a focusing drive unit, a focusing position detection unit and a focusing limit detection unit; wherein, the focusing drive unit, the focusing position detection unit and the focusing limit detection unit are respectively connected to the main control module, and the focusing drive unit is further connected to the focusing voice coil motor; the focusing drive unit is configured to output a first focusing control signal and a second focusing control signal to the focusing voice coil motor according to the focusing PWM wave and the focusing voltage threshold, so as to change the rotation direction and driving force of the focusing voice coil motor; the focusing position detection unit is configured to measure the magnetic pole strength at the focusing voice coil motor, and send a first focusing voltage signal and a second focusing voltage signal to the main control module, so that the main control module calculates the displacement of the focusing voice coil motor; the first focusing control signal is a voltage signal generated according to the duty cycle of the focusing PWM wave, and is used to change the rotation direction and rotation speed of the focusing voice coil motor; the second focusing control signal is a current signal generated according to the focusing voltage threshold, and is used to change the driving force of the focusing voice coil motor, so that the focusing voice coil motor drives the camera lens to rotate to the target position; the focusing limit detection unit is configured to detect the limit point of the focusing voice coil motor, so that the main control module performs error correction according to the displacement of the focusing voice coil motor and the limit point of the focusing voice coil motor during the stroke of the focusing voice coil motor, obtains a focusing error correction result, and updates the focusing PWM wave according to the focusing error correction result; the main control module includes: a first focusing signal output terminal, a second focusing signal output terminal, a third focusing signal output terminal and a first digital-to-analog signal output terminal; wherein, the first focusing signal output terminal, the second focusing signal output terminal and the third focusing signal output terminal are connected to the focusing drive unit, and the first digital-to-analog signal output terminal is connected to the focusing drive unit; The main control module is configured to send a first focusing PWM wave to the focusing driving unit through the first focusing signal output terminal; The main control module is further configured to send a second focusing PWM wave to the focusing driving unit through the second focusing signal output terminal; The main control module is further configured to send a focusing selection signal to the focusing driving unit through the third focusing signal output terminal, so that the focusing driving unit selects a focusing PWM wave from the first focusing PWM wave and the second focusing PWM wave; The main control module is further configured to output a focusing voltage threshold to the focusing driving unit through the first digital-to-analog signal output terminal, so as to change the driving force of the focusing voice coil motor through the focusing driving unit.

2. The camera focusing driving circuit according to claim 1, wherein, The main control module further includes: a first analog-to-digital signal input terminal and a second analog-to-digital signal input terminal, and the first analog-to-digital signal input terminal and the second analog-to-digital signal input terminal are connected to the focusing position detection unit; The main control module is configured to receive a first focusing voltage signal transmitted by the focusing position detection unit through the first analog-to-digital signal input terminal; The main control module is further configured to receive a second focusing voltage signal transmitted by the focusing position detection unit through the second analog-to-digital signal input terminal; The main control module is further configured to calculate the displacement of the focusing voice coil motor according to the first focusing voltage signal and the second focusing voltage signal.

3. The camera focusing driving circuit according to claim 1, wherein, The zoom driving module includes: a zoom driving unit, a zoom position detection unit, and a zoom limit detection unit; wherein, the zoom driving unit, the zoom position detection unit, and the zoom limit detection unit are respectively connected to the main control module, and the zoom driving unit is further connected to a zoom voice coil motor; The zoom driving unit is configured to output a first zoom control signal and a second zoom control signal to the zoom voice coil motor according to the zoom PWM wave and the zoom voltage threshold, so as to change the rotation direction and driving force of the zoom voice coil motor; the first zoom control signal is a voltage signal generated according to the duty cycle of the zoom PWM wave, and is used to change the rotation direction and speed of the zoom voice coil motor 500; the second zoom control signal is a current signal generated according to the zoom voltage threshold, and is used to change the driving force of the zoom voice coil motor, so that the zoom voice coil motor drives the camera lens to rotate to a target position; The zoom position detection unit is configured to measure the magnetic pole strength at the zoom voice coil motor, and send a first zoom voltage signal and a second zoom voltage signal to the main control module, so that the main control module calculates the displacement of the zoom voice coil motor; The zoom limit detection unit is configured to detect the limit point of the zoom voice coil motor, so that the main control module performs error correction according to the displacement of the zoom voice coil motor and the limit point of the zoom voice coil motor during the stroke of the zoom voice coil motor, obtains a zoom error correction result, and updates the zoom PWM wave according to the zoom error correction result.

4. The camera focusing driving circuit according to claim 3, It is characterized in that the main control module includes: a first zoom signal output terminal, a second zoom signal output terminal, a third zoom signal output terminal, and a second digital-to-analog signal output terminal; wherein, the first zoom signal output terminal, the second zoom signal output terminal, and the third zoom signal output terminal are connected to the zoom driving unit, and the second digital-to-analog signal output terminal is connected to the zoom driving unit; the main control module is configured to send a first zoom PWM wave to the zoom driving unit through the first zoom signal output terminal; the main control module is further configured to send a second zoom PWM wave to the zoom driving unit through the second zoom signal output terminal; the main control module is further configured to send a zoom selection signal to the zoom driving unit through the third zoom signal output terminal, so that the zoom driving unit selects a zoom PWM wave from the first zoom PWM wave and the second zoom PWM wave; the main control module is further configured to output a zoom voltage threshold to the zoom driving unit through the second digital-to-analog signal output terminal, so as to change the driving force of the zoom voice coil motor through the zoom driving unit.

5. The camera focusing drive circuit according to claim 3, It is characterized in that the main control module further includes: a third analog-to-digital signal input terminal and a fourth analog-to-digital signal input terminal, and the third analog-to-digital signal input terminal and the fourth analog-to-digital signal input terminal are connected to the zoom position detection unit; the main control module is configured to receive a first zoom voltage signal transmitted by the zoom position detection unit through the third analog-to-digital signal input terminal; the main control module is further configured to receive a second zoom voltage signal transmitted by the zoom position detection unit through the fourth analog-to-digital signal input terminal; the main control module is further configured to calculate the displacement of the zoom voice coil motor according to the first zoom voltage signal and the second zoom voltage signal.

6. The camera focusing drive circuit according to any one of claims 1 to 5, It is characterized in that the camera focusing drive circuit further includes a debugging module and a serial port module respectively connected to the main control module.

7. The camera focusing drive circuit according to any one of claims 1 to 5, It is characterized in that the camera focusing drive circuit further includes: a power supply module, the power supply module is connected to the main control module and the focusing drive unit, and the power supply module is further connected to the zoom drive unit; the power supply module is configured to supply electrical energy to each module.

8. A camera focusing drive method, It is characterized in that the camera focusing drive method is applied to the camera focusing drive circuit according to any one of claims 1 to 7. The camera focusing drive circuit includes: a main control module, a focusing drive module and a zoom drive module respectively connected to the main control module. The focusing drive module is connected to a focusing voice coil motor, and the zoom drive module is connected to a zoom voice coil motor. The camera focusing drive method includes: the main control module outputs a focusing PWM wave and a focusing voltage threshold to the focusing drive module, and outputs a zoom PWM wave and a zoom voltage threshold to the zoom drive module; The focusing drive module drives a focusing voice coil motor according to the focusing PWM wave and the focusing voltage threshold, and changes the rotation direction and driving force of the focusing voice coil motor so that the camera lens completes focusing; The zoom drive module drives a zoom voice coil motor according to the zoom PWM wave and the zoom voltage threshold, and changes the rotation direction and driving force of the zoom voice coil motor so that the camera lens completes zooming.

Images