CN207075049U

CN207075049U - A kind of auto iris drive circuit and electronic installation

Info

Publication number: CN207075049U
Application number: CN201720512283.7U
Authority: CN
Inventors: 冯宝库
Original assignee: Beijing Megvii Technology Co Ltd; Beijing Maigewei Technology Co Ltd
Current assignee: Beijing Megvii Technology Co Ltd; Beijing Maigewei Technology Co Ltd
Priority date: 2017-05-09
Filing date: 2017-05-09
Publication date: 2018-03-06
Anticipated expiration: 2027-05-09

Abstract

The utility model provides a kind of auto iris drive circuit and electronic installation, including：FEP, the first D/A converter module, the first comparison module, the second D/A converter module and the second comparison module, the first D/A converter module receive the first digital coding from FEP and generate the first analog voltage；The normal phase input end of first comparison module receives the first analog voltage exported by the first D/A converter module, the inverting input of first comparison module receives reference voltage value, first comparison module is compared to the first analog voltage and reference voltage value, so as to control aperture pace of change；Second D/A converter module receives the second digital coding from FEP and generates the second analog voltage；The second analog voltage and the feedback voltage fed back to through the second comparison module are compared by the second comparison module, the size that control aperture is opened.Circuit of the present utility model can accurately control the size and aperture velocity of rotation that aperture is opened.

Description

A kind of auto iris drive circuit and electronic installation

Technical field

The utility model is related to a kind of security monitoring technology, in particular to a kind of auto iris drive circuit with And electronic installation.

Background technology

Video camera is widely used on each emporium, hotel, school, traffic intersection, residential quarters, office space and other places Side, for carrying out daily monitoring to these places, play a part of security protection.

Security monitoring video camera generally use automatic diaphragm lens, with the change of light, video camera changes automatic according to light Adjust aperture size so that brightness of image keeps basically identical.DC driven aperture (DC-iris) is a kind of light of specific type Circle, by camera control, the quantity of the light of entrance can be automatically adjusted, belongs to the aperture drive circuit of current main flow.Usual direct current There are four signals on driving auto iris joint：Damping just (damping+), damping is negative (damping -), and driving just (driving+), driving is negative (driving -).

The scheme 1 of aperture drive circuit relatively common at present is that high-definition image snap shot is formed SD image by video camera, Analog video is generated through digital-to-analogue conversion, circuit compares according to the amplitude size of this analog video with fixed level, and control is automatic The circuit of the stop opening of aperture camera lens.But such a scheme can not accurately control aperture size, dark images can only be realized Shi Zeng great apertures, reduce aperture when image is bright, but the actual size of now f-number can not be known.

The scheme of another aperture drive circuit be by simple circuit only control driving+, driving-, i.e., only control The change of aperture size, for governing speed signal damping+, damp-do not control, so reduce circuit, reduce cost.This side Although case can realize aperture size control, aperture governing speed is not controlled, in ambient light acute variation, adjusted It is undesirable to save effect.

Therefore, in order to solve the above-mentioned technical problem, the utility model provide a kind of new auto iris drive circuit and Electronic installation.

Utility model content

In order to solve the above-mentioned technical problem, on the one hand the utility model provides a kind of auto iris drive circuit, including：

FEP, for analyzing present image brightness, and judge whether the present image brightness meets Setting value；

First D/A converter module, receive the first digital coding from the FEP and generate the first simulation electricity Pressure, when the gap between the present image brightness and the setting value is bigger, as described in generating the FEP First digital coding is smaller, and the value of first analog voltage is smaller；

First comparison module, the normal phase input end reception of first comparison module are defeated by first D/A converter module First analog voltage gone out, the inverting input of first comparison module receive reference voltage value, wherein, described first The value of analog voltage is more than or equal to the value of the reference voltage, and first comparison module is to first analog voltage and described Reference voltage value is compared, if the value of first analog voltage is more than the reference voltage, first comparison module First analog voltage is exported to damp just to auto iris interface pin, to adjust the size of damping coil control damping, from And aperture pace of change is controlled, if the value of first analog voltage is equal to the reference voltage, first comparison module Export as 0；

Second D/A converter module, receive the second digital coding from the FEP and generate the second simulation electricity Pressure, wherein, as low more of setting value described in the present image brightness ratio, generated by the FEP described the Two digital codings are bigger, and the value of second analog voltage is higher, as much higher than the setting value of the present intensity, by Second digital coding of the FEP generation is smaller；

Second comparison module, the normal phase input end of second comparison module receive the second D/A converter module output Second analog voltage, the negative-phase input of second comparison module receives the output end from second comparison module The feedback voltage for being output to the driving of auto iris interface pin and returning just and through the driving negative-feedback of auto iris interface pin, described the Two comparison modules are compared to second analog voltage and the feedback voltage, when second analog voltage is more than described During feedback voltage, regulation driving coil makes aperture become big, when second analog voltage is less than the feedback voltage, adjusts institute Stating driving coil makes aperture diminish, and when the second analog voltage and the equal feedback voltage, aperture is stable.

Further, first numeral that the reference voltage is defined as being written in first D/A converter module is compiled The analog voltage that code first D/A converter module described in when 0 exports.

Further, first digital coding and second digital coding that the FEP is generated are by IIC Bus is respectively transmitted to first D/A converter module and second D/A converter module.

Further, first D/A converter module includes the first digital analog converter, and first digital analog converter includes The interface to match with iic bus, wherein, first digital analog converter is used for described with the interface that iic bus matches First D/A converter module transmits first digital coding；

Second D/A converter module includes the second digital analog converter, and second digital analog converter includes total with IIC The interface that line matches, wherein, second digital analog converter is used for second digital-to-analogue with the interface that iic bus matches Modular converter transmits second digital coding.

Further, first digital analog converter is the digital analog converter of 8 IIC interfaces, and/or, second digital-to-analogue Converter is the digital analog converter of 8 IIC interfaces.

Further, the iic bus is n positions iic bus, wherein, n 8,10,12 or 16, by iic bus to described First D/A converter module and second D/A converter module are configured, first digital coding and second numeral It is encoded to 0 to 2ⁿNatural number between -1, accordingly by first D/A converter module output the first analog voltage value and The value of second analog voltage changes from the reference voltage to supply voltage, wherein, the supply voltage refers to by powering Power supply is applied to first D/A converter module and/or the supply voltage being applied in second D/A converter module.

Further, in addition to the first filtration module, first filtration module are used for by the first digital-to-analogue conversion mould First analog voltage of block generation is filtered, it is filtered after first analog voltage be input to described first and compare The normal phase input end of module.

Further, first filtration module includes the first electric capacity and first resistor, first resistor one end electrical connection To the output end of first D/A converter module, the other end ground connection of the first resistor, the anode electricity of first electric capacity It is connected to the normal phase input end of first comparison module, the minus earth of first electric capacity.

Further, the first pin ground connection of first digital analog converter, its IIC address is 0 × 0C；

Second pin of first digital analog converter is serial clock input, for receiving by iic bus transmission Serial clock signal；

The three-prong of first digital analog converter is data input pin, for receiving as described in iic bus transmission First digital coding；

4th pin of first digital analog converter is electrically connected to the first power supply；

The 5th pin ground connection of first digital analog converter；

6th pin of first digital analog converter is analog voltage output end, for exporting the first simulation electricity Pressure.

Further, in addition to the second electric capacity, for carrying out decoupling filtering, second electric capacity to first power supply Anode be electrically connected to first power supply, the minus earth of second electric capacity.

Further, in addition to the second filtration module, second filtration module are used for by the second digital-to-analogue conversion mould Second analog voltage of block generation is filtered, it is filtered after second analog voltage be input to described second and compare The normal phase input end of module.

Further, second filtration module includes the 3rd electric capacity and second resistance, second resistance one end electrical connection To the output end of second D/A converter module, the other end ground connection of the second resistance, the anode electricity of the 3rd electric capacity It is connected to the normal phase input end of second comparison module, the minus earth of the 3rd electric capacity.

Further, the first pin of second digital analog converter is connected to the second power supply through 3rd resistor, its IIC Location is 0 × 0F, and the 3rd resistor is used for the first pin that second digital analog converter is flowed into second power supply Current limitation；

Second pin of second digital analog converter is serial clock input, for receiving by iic bus transmission Serial clock signal；

The three-prong of second digital analog converter is data input pin, for receiving as described in iic bus transmission Second digital coding；

4th pin of second digital analog converter is electrically connected to second power supply；

The 5th pin ground connection of second digital analog converter；

6th pin of second digital analog converter is analog voltage output end, for exporting the second simulation electricity Pressure.

Further, in addition to the 4th electric capacity, for carrying out decoupling filtering, the 4th electric capacity to second power supply Anode be electrically connected to second power supply, the minus earth of the 4th electric capacity.

Further, in addition to bleeder circuit, the voltage of the dividing point of the bleeder circuit is the reference voltage, wherein, The bleeder circuit includes the 4th resistance and the 5th resistance being connected in series between the 3rd power supply and ground, wherein, it is described Dividing point is removed between the 4th resistance and the 5th resistance, and is electrically connected to the anti-phase defeated of first comparison module Enter end.

Further, in addition to the 6th resistance, described 6th resistance one end are electrically connected to the auto iris interface pin and driven It is dynamic negative, other end ground connection, the release path as the driving coil electric current of camera lens.

Further, in addition to the 7th resistance, the 7th resistance is connected electrically in first comparison module and described automatic Between the damping just of aperture interface pin, for the output current limiting to first comparison module.

Further, the negative ground connection of auto iris interface pin damping.

Further, first comparison module includes first comparator, and second comparison module includes the second comparator.

The utility model another further aspect provides a kind of electronic installation, including foregoing auto iris drive circuit.

The first analog voltage that auto iris drive circuit of the present utility model is generated using the first D/A converter module is believed Number control camera adjusting damping coil, with change damping size, so as to control aperture pace of change, use the second digital-to-analogue conversion The size that the second analog voltage signal regulation driving coil control aperture of module generation is opened, so as to of the present utility model automatic Aperture drive circuit can accurately control the size and aperture velocity of rotation that aperture is opened, even in ambient light acute variation When, it can also realize good regulating effect.

Electronic installation of the present utility model equally has above-mentioned excellent due to including foregoing auto iris drive circuit Point.

Brief description of the drawings

The utility model embodiment is described in more detail in conjunction with the accompanying drawings, it is of the present utility model above-mentioned and its Its purpose, feature and advantage will be apparent.Accompanying drawing is used for providing further understanding the utility model embodiment, and And a part for constitution instruction, it is used to explain the utility model together with the utility model embodiment, does not form to this reality With new limitation.In the accompanying drawings, identical reference number typically represents same parts or step.

In accompanying drawing：

Fig. 1 shows the auto iris system topological figure in an embodiment of the present utility model；

Fig. 2 shows the auto iris interface pin definition figure in an embodiment of the present utility model；

Fig. 3 shows the auto iris drive circuit figure in an embodiment of the present utility model.

Embodiment

In the following description, a large amount of concrete details are given more thoroughly to manage the utility model to provide Solution.It is, however, obvious to a person skilled in the art that the utility model can be without one or more of these thin Save and be carried out.In other examples, in order to avoid obscuring with the utility model, for more well known in the art Technical characteristic is not described.

It should be appreciated that the utility model can be implemented in different forms, and should not be construed as being limited to carry here The embodiment gone out.On the contrary, providing these embodiments disclosure will be made thoroughly and complete and the scope of the utility model is complete Ground passes to those skilled in the art.

The purpose of term as used herein is only that description specific embodiment and not as limitation of the present utility model. This is in use, " one " of singulative, "one" and " described/should " be also intended to include plural form, unless context understands finger Go out other mode.It is also to be understood that term " composition " and/or " comprising ", when in this specification in use, determine the feature, Integer, step, operation, the presence of element and/or part, but it is not excluded for one or more other features, integer, step, behaviour The presence or addition of work, element, part and/or group.Herein in use, term "and/or" includes any of related Listed Items And all combinations.

In order to thoroughly understand the utility model, detailed description will be given below, to explain skill of the present utility model Art scheme.Preferred embodiment of the present utility model is described in detail as follows, but in addition to these detailed descriptions, the utility model is also There can be other embodiment.

In order to solve foregoing technical problem, the utility model provides a kind of auto iris drive circuit, including：

Below, auto iris drive circuit of the present utility model is elaborated referring to figs. 1 to Fig. 3, wherein, Fig. 1 shows The auto iris system topological figure gone out in an embodiment of the present utility model；Fig. 2 shows an embodiment of the present utility model In auto iris interface pin definition figure；Fig. 3 shows the auto iris drive circuit in an embodiment of the present utility model Figure.

Specifically, as shown in figure 1, the auto iris drive circuit includes FEP, the FEP is used Analyzed in present image brightness, and judge whether present image brightness meets setting value.

Wherein, the setting value refers to that brightness of image meets the desired value of user, the setting value can according to different user for The requirement of the desired value of brightness of image is different to carry out reasonable set.

Exemplarily, present image monochrome information can be acquired by the device including such as imaging sensor, and will The current image luminance information is transferred in the FEP, for analyzing present image brightness, and judges to work as Whether preceding brightness of image meets setting value.

Further, present image monochrome information can be converted into digital coding by the FEP, for example, passing through collection Present image monochrome information is converted into digital coding into the luminance coding device in FEP.

Exemplarily, as shown in Fig. 2 the auto iris interface pin includes：Driving just (driving+), the negative (drive of driving It is dynamic -), damping just (damping+) and damping negative (damping -) four interface pins.

Exemplarily, as shown in figure 1, auto iris of the present utility model includes driving circuit and damping circuit, drive back Road is being connected to the driving of auto iris interface pin just, and through driving forward drive coil transmission signal, driving coil is rotated so as to control F-stop is opened or closed, and electric current feeds back to driving circuit again from the decent driving coil of driving to driving is negative；Damping circuit connects It is connected to the damping of auto iris interface pin just, through damping positive damping coil transmission signal, damping coil is rotated so as to control resistance Buddhist nun becomes big or diminished, and electric current is negative to damping from decent damping coil is damped, and damps negative ground connection GND.

In one example, auto iris drive circuit of the present utility model also includes the first D/A converter module and first Comparison module, first D/A converter module receive the first digital coding from the FEP and generate the first mould Intend voltage, when the gap between the present image brightness and the setting value is bigger, generated by the FEP First digital coding is smaller, and the value of first analog voltage is smaller.

Further, the normal phase input end of first comparison module is received by first D/A converter module output First analog voltage, the inverting input of first comparison module receive reference voltage value, wherein, first simulation The value of voltage is more than or equal to the value of the reference voltage, and first comparison module is to first analog voltage and the benchmark Magnitude of voltage is compared, if the value of first analog voltage is more than the reference voltage, the first comparison module output First analog voltage damps just to auto iris interface pin, to adjust the size of damping coil control damping, so as to control F-stop pace of change, if the value of first analog voltage is equal to the reference voltage, the first comparison module output For 0.

Wherein, the difference of the reference voltage and first analog voltage between the two is bigger, then from first comparator The magnitude of voltage of middle output is bigger, then the electric current being input in damping circuit is bigger, adjusts damping coil, makes damping bigger, aperture Pace of change is smaller, and when difference is zero between first analog voltage and the reference voltage value, described first compares mould The voltage of block output is 0V, then no current is being input to the damping of auto iris interface pin just, and no current flows through in camera lens, now hinders Buddhist nun is minimum, and aperture pace of change is maximum.

Specifically, the first digital coding generated by the FEP according to present image brightness is total by integrated circuit Line (inter-Integrated Circuit, abbreviation iic bus) is transferred to first D/A converter module, can also use It is well known to those skilled in the art other can be by the first digital code transmission to the first D/A converter module connection mode.

Exemplarily, the iic bus is n positions iic bus, wherein, n 8,10,12 or 16, by iic bus to institute State the first D/A converter module to be configured, then first digital coding is 0 to 2ⁿNatural number between -1, accordingly by described The value of first analog voltage of the first D/A converter module output changes from the reference voltage to supply voltage, wherein, The supply voltage refers to the supply voltage being applied to by power supply in first D/A converter module.For example, iic bus For 8 iic bus, then first D/A converter module is configured by 8 iic bus, then first digital coding For 0 to 2⁸Natural number between -1, accordingly by first D/A converter module output the first analog voltage value from described Reference voltage changes between supply voltage, and the first digitally coded numerical value is bigger, and the value of the first analog voltage of output is bigger.

Wherein, the reference voltage is defined as being written to first digital coding in first D/A converter module The analog voltage that first D/A converter module described in when 0 exports.For example, it is written in first D/A converter module First digital coding be 0 when, the analog voltage of output is 2.7V, then reference voltage is 2.7V.

Wherein, the supply voltage refers to the power supply electricity being applied to by power supply in first D/A converter module Pressure, the supply voltage value can be depending on the voltages that need to actually apply, for example, power supply provides 5V supply voltage.

In one example, it is 0 to 2 in the first digital coding⁸Random natural number between -1, then the first simulation exported The value of voltage changes in 2.7V between 5V.

Wherein, to the first D/A converter module write-in 0 to 2ⁿDifferent natural number between -1, each numerical value is corresponding to be generated The value of one first analog voltage, input numerical value is bigger, and analog voltage is higher.

Wherein, first D/A converter module includes the first digital analog converter U1, and the digital analog converter can also use Others can realize the functional modules such as the integrated circuit of digital-to-analogue conversion to substitute.

Exemplarily, the first digital analog converter U1 can be the digital analog converter of any types or model, not do herein It is specific to limit.

Further, in order to realize the connection between iic bus and the first digital analog converter, first digital analog converter Including the interface to match with iic bus, for example, when iic bus is 8 iic bus, then the first digital analog converter then can be with For the digital analog converter of 8 IIC interfaces, wherein, first digital analog converter is used for institute with the interface that iic bus matches State the first D/A converter module and transmit first digital coding.

In one example, as shown in figure 3, the first digital analog converter U1 includes following six pin, wherein, it is described First digital analog converter U1 the first pin 1 is grounded, and its IIC address is 0 × 0C；The second pipe of the first digital analog converter U1 Pin 2 is serial clock input, for receiving the serial clock signal transmitted by iic bus；The first digital analog converter U1 Three-prong 3 be data input pin, for receive by iic bus transmit first digital coding；First digital-to-analogue Converter U1 the 4th pin 4 is electrically connected to the first power supply；The 5th pin 5 of the first digital analog converter U1 is grounded； The 6th pin 6 of the first digital analog converter U1 is analog voltage output end, for exporting first analog voltage.

In one example, as shown in figure 3, auto iris drive circuit of the present utility model also includes the second electric capacity C2, For carrying out decoupling filtering to the first power supply of institute, the anode of second electric capacity is electrically connected to first power supply, The minus earth of second electric capacity.

Alternatively, the scope for the voltage that first power supply is provided can be carried out reasonable according to the requirement of actual circuit Selection, wherein, in the present embodiment, the supply voltage that first power supply is provided is 5V.

Wherein, first comparison module includes first comparator U3A, and the comparator can be that those skilled in the art are ripe The comparator of any model or type known, can also by can realize with the circuit of comparator identical voltage comparing function Lai Realize.

Exemplarily, as shown in figure 3, the first digital analog converter U1 the 6th pin 6 is electrically connected to the first comparator U3A normal phase input end, the first analog voltage exported from the first digital analog converter U1 is transferred to described first Comparator U3A.

In one example, auto iris drive circuit of the present utility model also includes the first filtration module, and described first Filtration module is used to be filtered first analog voltage generated by first D/A converter module, after filtered First analog voltage is input to the normal phase input end of first comparison module.

Wherein, the first filtration module can be realized by that can realize the filter circuit of filter function, for example, as shown in figure 3, First filtration module includes the first electric capacity C1 and first resistor R1, described first resistor R1 one end are electrically connected to described first The output end of D/A converter module, for example, being electrically connected to the first digital analog converter U1 output end, the first resistor R1's is another One end is grounded, and the anode of the first electric capacity C1 is electrically connected to the normal phase input end of first comparison module, for example, electrical connection To first comparator U3A normal phase input end, the minus earth of the first electric capacity C1, the first electric capacity C1 and first resistor R1 structures Into filter circuit, for being filtered to first analog voltage.

In one example, as shown in figure 3, auto iris drive circuit of the present utility model also includes bleeder circuit, institute Bleeder circuit to be stated to be used to generate the reference voltage, the voltage for removing dividing point of the bleeder circuit is the reference voltage, its In, the bleeder circuit includes the 4th resistance R4 and the 5th resistance R5 being connected in series between the 3rd power supply and ground GND, Wherein, described to remove dividing point between the 4th resistance R4 and the 5th resistance R5, described to go dividing point to be electrically connected to described The inverting input of first comparison module, for example, being electrically connected to the inverting input of the first comparator U3A.

Wherein, the supply voltage that the 3rd power supply described in the 4th resistance R4 and the 5th resistance R5 partial pressures provides, for example, institute The value for stating the supply voltage of the 3rd power supply offer is 5V, then the 4th resistance R4 and the 5th resistance R5 partial pressure 5V, removes dividing point Values of the voltage 2.7V as the reference voltage, can according to the value of required reference voltage, it is rational set the 4th resistance and The resistance of 5th resistance.

In one example, auto iris drive circuit of the present utility model also includes the 7th resistance R7, the 7th electricity Resistance R7 is connected electrically between first comparison module and auto iris interface pin damping just (damping+), for institute The output current limiting of the first comparison module is stated, to prevent excessive electric current scaling loss lens coil.For example, the 7th resistance R7 one end electricity First comparator U3A output end is connected to, the other end is electrically connected to the auto iris interface pin damping just (damping+).

Further, negative (damping -) ground connection of auto iris interface pin damping, the electric current as camera lens damping coil are released Path is put, forms damping circuit.

In one example, first comparator U3A is included in first comparison module, the first comparator U3A is also Be electrically connected between power supply and ground so that first comparator can normal work, alternatively, power supply provide power supply Voltage can be 5V.

The above-mentioned circuit loop for including the first D/A converter module and the first comparison module etc., as damping circuit, realize Regulation to damping size.

In use, being analyzed first by FEP present image brightness, and whether judge present image brightness Meet setting value, when the gap between the present image brightness and the setting value is bigger, given birth to by the FEP Into first digital coding it is smaller, the value of first analog voltage is smaller, between reference voltage and the first analog voltage Difference it is smaller, then damp smaller, aperture pace of change is faster, when between first analog voltage and the reference voltage value When difference is zero, first comparison module exports 0V voltages, and no current flows through in camera lens, and damping is minimum, aperture velocity of rotation It is most fast, conversely, when the gap between the present image brightness and the setting value is smaller, generated by the FEP First digital coding it is bigger, the value of first analog voltage is bigger, between reference voltage and the first analog voltage Difference is bigger, then damps bigger, and aperture pace of change is slower.

In a specific embodiment, to the first digital analog converter U1 write-ins 0~2⁸Different numerical value between -1, generation Different first analog voltages, input numerical value is bigger, and the first analog voltage is higher.When writing 0, output voltage 2.7V, write-in 2⁸- 1, Generate voltage 5V, when can be approximately now that present image brightness reaches setting value, or in equipment inherent damping maximum When.For first analog voltage compared with reference voltage 2.7V is through first comparator U3A, difference is bigger, and damping is bigger, aperture change speed Degree diminishes.When writing 0,2.7V voltages are produced, first comparator U3A exports 0V, and no current flows through in camera lens, and damping is minimum, Aperture pace of change is maximum.

Further, auto iris drive circuit of the present utility model also compares including the second D/A converter module and second Module, the second D/A converter module receive the second digital coding from the FEP and generate the second analog voltage, Wherein, as low more of setting value described in the present image brightness ratio, generated by the FEP described second Digital coding is bigger, and the value of second analog voltage is higher, as high more of setting value described in the present image brightness ratio, Second digital coding generated by the FEP is smaller.

Wherein, the normal phase input end of second comparison module receives the second mould of the second D/A converter module output Intend voltage, the negative-phase input of second comparison module, which is received from the output end of second comparison module, is output to automatic light Interface pin driving is enclosed just and through the feedback voltage of auto iris interface pin driving negative-feedback time, second comparison module pair Second analog voltage and the feedback voltage are compared, so that aperture drive circuit is according to second comparison module The size that comparative result control aperture is opened, when second analog voltage is more than the feedback voltage, adjusts driving coil Aperture is set to become big, when second analog voltage is less than the feedback voltage, adjusting the driving coil makes aperture diminish, when When the second analog voltage and the equal feedback voltage, aperture is stable.

Wherein, both the second analog voltage and the feedback voltage difference are bigger, and aperture, which is opened, becomes big, light-inletting quantity increase, When the second analog voltage and the equal feedback voltage, would not have again in the driving coil that control aperture is opened or closed Electric current flows through, and aperture is stable.

Specifically, the second digital coding generated by the FEP according to present image brightness is total by integrated circuit Line (inter-Integrated Circuit, abbreviation iic bus) is transferred to second D/A converter module, can also use It is well known to those skilled in the art other can be by the second digital code transmission to the second D/A converter module connection mode.

Exemplarily, the iic bus is n positions iic bus, wherein, n 8,10,12 or 16, by iic bus to institute State the second D/A converter module to be configured, then second digital coding is 0 to 2ⁿNatural number between -1, accordingly by described The value of second analog voltage of the second D/A converter module output changes from the reference voltage to supply voltage, wherein, The supply voltage refers to the supply voltage being applied to by power supply in second D/A converter module.For example, iic bus For 8 iic bus, then second D/A converter module is configured by 8 iic bus, then second digital coding For 0 to 2⁸Natural number between -1, accordingly by second D/A converter module output the second analog voltage value from described Reference voltage changes between supply voltage, and the second digitally coded numerical value is bigger, and the value of the second analog voltage of output is bigger.

Wherein, the reference voltage is defined as being written to second digital coding in second D/A converter module The analog voltage that second D/A converter module described in when 0 exports.For example, it is written in second D/A converter module Second digital coding be 0 when, the analog voltage of output is 2.7V, then reference voltage is 2.7V.

Wherein, the supply voltage refers to the power supply electricity being applied to by power supply in second D/A converter module Pressure, the supply voltage value can be depending on the voltages that need to actually apply, for example, power supply provides 5V supply voltage.

In one example, it is 0 to 2 in the second digital coding⁸Random natural number between -1, then the second simulation exported The value of voltage changes in 2.7V between 5V.

Wherein, to the second D/A converter module write-in 0 to 2ⁿDifferent natural number between -1, each numerical value is corresponding to be generated The value of one second analog voltage, input numerical value is bigger, and analog voltage is higher.

Wherein, second D/A converter module includes the second digital analog converter U2, and also the digital analog converter can also make The functional modules such as the integrated circuit of digital-to-analogue conversion can be realized with others to substitute.

Exemplarily, the second digital analog converter U2 can be the digital analog converter of any types or model, not do herein It is specific to limit.

Further, in order to realize the connection between iic bus and the second digital analog converter, second digital analog converter Including the interface to match with iic bus, for example, when iic bus is 8 iic bus, then the second digital analog converter then can be with For the digital analog converter of 8 IIC interfaces, wherein, second digital analog converter is used for institute with the interface that iic bus matches State the second D/A converter module and transmit second digital coding.

Further, the first pin 1 of the second digital analog converter U2 is connected to the second power supply through 3rd resistor R3, Its IIC address is 0 × 0F, and the 3rd resistor R3 is used to flowing into the second power supply the of the second digital analog converter U2 The electric current of one pin 1 plays metering function；The second pin 2 of the second digital analog converter U2 is serial clock input, is used for Receive the serial clock signal transmitted by iic bus；The three-prong 3 of the second digital analog converter U2 is data input pin, For receiving second digital coding transmitted by iic bus；The 4th pin 4 of the second digital analog converter U2 electrically connects To second power supply；The 5th pin 5 of the second digital analog converter U2 is grounded；The second digital analog converter U2's 6th pin 6 is analog voltage output end, for exporting second analog voltage.

In one example, auto iris drive circuit of the present utility model also includes the 4th electric capacity C4, for institute the Two power supplies carry out decoupling filtering, and the anode of the 4th electric capacity C4 is electrically connected to second power supply, and the described 4th Electric capacity C4 minus earth.

Alternatively, the scope for the voltage that second power supply is provided can be carried out reasonable according to the requirement of actual circuit Selection, wherein, in the present embodiment, the supply voltage that second power supply is provided is 5V.

Wherein, second comparison module includes the second comparator U3B, and the comparator can be that those skilled in the art are ripe The comparator of any model or type known, can also by can realize with the circuit of comparator identical voltage comparing function Lai Realize.

Exemplarily, as shown in figure 3, the second digital analog converter U2 the 6th pin 6 is electrically connected to second comparator U3B normal phase input end, the second analog voltage exported from the second digital analog converter U2 is transferred to described second Comparator U3B.

Exemplarily, as shown in figure 3, the second comparator U3B output end is electrically connected to the driving of auto iris interface pin Just, the electric current from the second comparator U3B outputs is made just to be flowed into driving coil through driving, the driving coil is used to control aperture Open or close.

Further, as shown in figure 3, auto iris interface pin driving negative electricity is connected to the negative input of the second comparator End, the driving of auto iris interface pin will be output to just again through aperture of overdriving from the output end of the second comparator U3B The negative that the feedback voltage returned again through the driving negative-feedback of auto iris interface pin is input to the second comparator U3B inputs End.

Further, it is described as shown in figure 3, auto iris drive circuit of the present utility model also includes the 6th resistance R6 6th resistance R6 one end is electrically connected to the auto iris interface pin driving and born, other end ground connection, the drives line as camera lens The release path of loop current.

In one example, auto iris drive circuit of the present utility model also includes the second filtration module, and described second Filtration module is used to be filtered second analog voltage generated by second D/A converter module, after filtered Second analog voltage is input to the normal phase input end of second comparison module.

Wherein, the second filtration module can be realized by that can realize the filter circuit of filter function, for example, as shown in figure 3, Second filtration module includes the 3rd electric capacity C3 and second resistance R2, and described second resistance R2 one end is electrically connected to described second The output end of D/A converter module, for example, being electrically connected to the output end of the second digital analog converter U2, the second resistance R2 The other end ground connection, the anode of the 3rd electric capacity C3 is electrically connected to the normal phase input end of second comparison module, for example, electric It is connected to the second comparator U3B normal phase input end, the minus earth of the 3rd electric capacity C3,

In one example, the second comparator U3B is included in second comparison module, the second comparator U3B is also Be electrically connected between power supply and ground so that the second comparator U3B can normal work, alternatively, power supply provide Supply voltage can be 5V.

The above-mentioned circuit loop for including the second D/A converter module and the second comparison module etc., as driving circuit, realize The regulation of size is opened to aperture, by the control to the second D/A converter module, by aperture Close All to fully open point For 2⁸(or other suitable 2ⁿ) step-length, write the size that different numerical value can accurately control aperture to open.

In use, being analyzed first by FEP present image brightness, and whether judge present image brightness Meet setting value, as low more of setting value described in the present image brightness ratio, the institute that is generated by the FEP State the second digital coding it is bigger (namely than present image meet during setting value by the FEP generate second numeral compile Big more of code), the value of second analog voltage is higher, as much higher than the setting value of the present intensity, by institute Second digital coding of stating FEP generation is smaller (namely by the front end when meeting setting value than present image Manage small more of the second digital coding of device generation).

Wherein, the normal phase input end of second comparison module receives the second mould of the second D/A converter module output Intend voltage, the negative-phase input of second comparison module, which is received from the output end of second comparison module, is output to automatic light Interface pin driving is enclosed just and through the feedback voltage of auto iris interface pin driving negative-feedback time, to second analog voltage It is compared with the feedback voltage, both the second analog voltage and the feedback voltage difference are bigger, and aperture, which is opened, becomes big, enters Light quantity increases, and after aperture reaches predefined size, the second analog voltage is consistent with the feedback voltage, and control aperture beats on or off There would not be electric current to flow through again in the coil closed, aperture is stable.Conversely, got over when the present intensity is higher than the setting value More, second digital coding generated by the FEP is smaller, by described the of the output of the second D/A converter module The value of two analog voltages is lower, then aperture is opened and diminished, and light-inletting quantity reduces, when second analog voltage is more than the feedback electricity During pressure, regulation driving coil makes aperture become big, when second analog voltage is less than the feedback voltage, adjusts the driving Coil makes aperture diminish, and when the second analog voltage and the equal feedback voltage, control aperture is opened or the coil of closing Interior to have electric current to flow through again, aperture is stable.

Exemplarily, to the second digital analog converter U2 write-ins 0~2⁸Different numerical value between -1, generate different second moulds Intend voltage, input numerical value is bigger, and the second analog voltage is higher；When writing 0, the second analog voltage of output is 2.7V, write-in 2⁸- 1, It is generated as the second analog voltage 5V.Second analog voltage compares with the feedback voltage fed back to through the second comparator U3B, difference Bigger, aperture, which is opened, becomes big, light-inletting quantity increase.A magnitude of voltage is often generated, camera lens Inside coil can produce an electric current, drive Aperture changes, the second analog voltage of the voltage fed back to after aperture reaches predefined size and the second digital analog converter U2 outputs It is equal, there would not be electric current to flow through again in coil, aperture is stable.It is by the control to the second analog voltage U2, aperture is whole Close to fully open and be divided into 2⁸Step-length, write the size that different numerical value can accurately control aperture to open.

So far the explanation and illustration of the key component to auto iris drive circuit of the present utility model is completed, for complete Whole drive circuit is also possible that other parts and circuit part, does not do repeat one by one herein.

In summary, auto iris drive circuit of the present utility model uses the first mould that the first D/A converter module generates Intend voltage signal control camera adjusting damping coil, to change the size of damping, so as to control aperture pace of change, use second The size that the second analog voltage signal regulation driving coil control aperture of D/A converter module generation is opened, so as to which this practicality is new The auto iris drive circuit of type can accurately control the size and aperture velocity of rotation that aperture is opened, even in ambient light During acute variation, good regulating effect can be also realized.

Implement two

The utility model also provides a kind of including the foregoing electronic installation for implementing the auto iris drive circuit described in one.

The electronic installation of the present embodiment, can be mobile phone, tablet personal computer, notebook computer, net book, game machine, TV Any electronic product such as machine, VCD, DVD, navigator, DPF, camera, video camera, recording pen, MP3, MP4, PSP is set It is standby, or any intermediate products including circuit.The electronic installation of the utility model embodiment, due to having used above-mentioned electricity Road, thus there is better performance.

In one example, the electronic installation in the present embodiment is video camera, wherein the video camera includes embodiment one Described auto iris drive circuit, the auto iris drive circuit include：

Because electronic installation of the present utility model includes foregoing auto iris drive circuit, so the auto iris drives Circuit has the advantage that same electronic installation also has.

The utility model is illustrated by above-described embodiment, but it is to be understood that, above-described embodiment is For the purpose illustrated and illustrated, and it is not intended to the utility model being limited in described scope of embodiments.This area skill Art personnel will also be appreciated that the utility model is not limited to above-described embodiment, may be used also according to teaching of the present utility model To make more kinds of variants and modifications, these variants and modifications are all fallen within the utility model scope claimed. The scope of protection of the utility model is defined by the appended claims and its equivalent scope.

Claims

A kind of 1. auto iris drive circuit, it is characterised in that including：

FEP, for analyzing present image brightness, and judge whether the present image brightness meets to set Value；

First D/A converter module, receive the first digital coding from the FEP and generate the first analog voltage；

First comparison module, the normal phase input end of first comparison module are received by first D/A converter module output First analog voltage, the inverting input of first comparison module receive reference voltage value, wherein, first simulation The value of voltage is more than or equal to the value of the reference voltage；

Second D/A converter module, receive the second digital coding from the FEP and generate the second analog voltage；

Second comparison module, the normal phase input end of second comparison module receive the institute of the second D/A converter module output The second analog voltage is stated, the negative-phase input of second comparison module receives to be exported from the output end of second comparison module The feedback voltage just and through the driving negative-feedback of auto iris interface pin returned to the driving of auto iris interface pin.
2. auto iris drive circuit as claimed in claim 1, it is characterised in that the reference voltage is defined as being written to institute State the simulation electricity that the first digital coding first D/A converter module described in when 0 in the first D/A converter module exports Pressure value.
3. auto iris drive circuit as claimed in claim 1, it is characterised in that the FEP is generated described First digital coding and second digital coding are respectively transmitted to first D/A converter module and described by iic bus Two D/A converter modules.
4. auto iris drive circuit as claimed in claim 1, it is characterised in that

First D/A converter module includes the first digital analog converter, and first digital analog converter includes and iic bus phase The interface of matching, wherein, first digital analog converter is used for first digital-to-analogue conversion with the interface that iic bus matches First digital coding described in module transfer；

Second D/A converter module includes the second digital analog converter, and second digital analog converter includes and iic bus phase The interface of matching, wherein, second digital analog converter is used for second digital-to-analogue conversion with the interface that iic bus matches Second digital coding described in module transfer.
5. auto iris drive circuit as claimed in claim 4, it is characterised in that first digital analog converter is 8 IIC The digital analog converter of interface, and/or, second digital analog converter is the digital analog converter of 8 IIC interfaces.
6. auto iris drive circuit as claimed in claim 3, it is characterised in that the iic bus is n positions iic bus, its In, n 8,10,12 or 16, first D/A converter module and second D/A converter module are carried out by iic bus Configuration, first digital coding and second digital coding are 0 to 2ⁿNatural number between -1, accordingly counted by described first Mould modular converter output the first analog voltage value and the second analog voltage value from the reference voltage to supply voltage it Between change, wherein, the supply voltage refers to be applied to first D/A converter module by power supply and/or is applied to institute State the supply voltage in the second D/A converter module.
7. auto iris drive circuit as claimed in claim 1, it is characterised in that also including the first filtration module, described One filtration module is used to be filtered first analog voltage generated by first D/A converter module, after filtered First analog voltage be input to the normal phase input end of first comparison module.
8. auto iris drive circuit as claimed in claim 7, it is characterised in that first filtration module includes the first electricity Hold and first resistor, described first resistor one end are electrically connected to the output end of first D/A converter module, first electricity The other end ground connection of resistance, the anode of first electric capacity are electrically connected to the normal phase input end of first comparison module, and described the The minus earth of one electric capacity.
9. auto iris drive circuit as claimed in claim 4, it is characterised in that

The first pin ground connection of first digital analog converter, its IIC address is 0 × 0C；

Second pin of first digital analog converter is serial clock input, for receiving by the serial of iic bus transmission Clock signal；

The three-prong of first digital analog converter is data input pin, for receiving by described the first of iic bus transmission Digital coding；

4th pin of first digital analog converter is electrically connected to the first power supply；

The 5th pin ground connection of first digital analog converter；

6th pin of first digital analog converter is analog voltage output end, for exporting first analog voltage.
10. auto iris drive circuit as claimed in claim 9, it is characterised in that also including the second electric capacity, for institute To state the first power supply and carry out decoupling filtering, the anode of second electric capacity is electrically connected to first power supply, and described the The minus earth of two electric capacity.
11. auto iris drive circuit as claimed in claim 1, it is characterised in that also including the second filtration module, described Two filtration modules are used to be filtered second analog voltage generated by second D/A converter module, after filtered Second analog voltage be input to the normal phase input end of second comparison module.
12. auto iris drive circuit as claimed in claim 11, it is characterised in that second filtration module includes the 3rd Electric capacity and second resistance, described second resistance one end are electrically connected to the output end of second D/A converter module, and described second The other end ground connection of resistance, the anode of the 3rd electric capacity is electrically connected to the normal phase input end of second comparison module, described The minus earth of 3rd electric capacity.
13. auto iris drive circuit as claimed in claim 4, it is characterised in that

First pin of second digital analog converter is connected to the second power supply through 3rd resistor, and its IIC address is 0 × 0F, The 3rd resistor is used for the current limitation that the first pin of second digital analog converter is flowed into second power supply；

Second pin of second digital analog converter is serial clock input, for receiving by the serial of iic bus transmission Clock signal；

The three-prong of second digital analog converter is data input pin, for receiving by described the second of iic bus transmission Digital coding；

4th pin of second digital analog converter is electrically connected to second power supply；

The 5th pin ground connection of second digital analog converter；

6th pin of second digital analog converter is analog voltage output end, for exporting second analog voltage.
14. auto iris drive circuit as claimed in claim 13, it is characterised in that also including the 4th electric capacity, for institute To state the second power supply and carry out decoupling filtering, the anode of the 4th electric capacity is electrically connected to second power supply, and described the The minus earth of four electric capacity.
15. auto iris drive circuit as claimed in claim 1, it is characterised in that also including bleeder circuit, the partial pressure electricity The voltage for removing dividing point on road is the reference voltage, wherein, the bleeder circuit includes being connected in series in the 3rd power supply The 4th resistance and the 5th resistance between ground, wherein, it is described to go dividing point to be located at the 4th resistance and the 5th resistance Between, and it is electrically connected to the inverting input of first comparison module.
16. auto iris drive circuit as claimed in claim 1, it is characterised in that also including the 6th resistance, the 6th electricity It is negative that resistance one end is electrically connected to auto iris interface pin driving, other end ground connection, the driving coil electric current as camera lens Discharge path.
17. auto iris drive circuit as claimed in claim 1, it is characterised in that also including the 7th resistance, the 7th electricity Resistance is connected electrically between first comparison module and auto iris interface pin damping just, for comparing described first The output current limiting of module.
18. auto iris drive circuit as claimed in claim 1, it is characterised in that the damping of auto iris interface pin is negative to be connect Ground.
19. auto iris drive circuit as claimed in claim 1, it is characterised in that first comparison module includes first Comparator, second comparison module include the second comparator.
20. a kind of electronic installation, it is characterised in that including the auto iris drive circuit described in one of claim 1 to 19.