CN109075755A - A kind of range sensor receives analog front circuit and range sensor - Google Patents
A kind of range sensor receives analog front circuit and range sensor Download PDFInfo
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- CN109075755A CN109075755A CN201880001032.XA CN201880001032A CN109075755A CN 109075755 A CN109075755 A CN 109075755A CN 201880001032 A CN201880001032 A CN 201880001032A CN 109075755 A CN109075755 A CN 109075755A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
- H03F3/45179—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using MOSFET transistors as the active amplifying circuit
- H03F3/45183—Long tailed pairs
- H03F3/45188—Non-folded cascode stages
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
- H03F2203/45—Indexing scheme relating to differential amplifiers
- H03F2203/45396—Indexing scheme relating to differential amplifiers the AAC comprising one or more switches
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Abstract
This application involves range sensor technical field, provides a kind of range sensor and receive analog front circuit and range sensor.The front-end circuit includes: photodiode, current integration module, reverse phase amplification module and cancellation module；The first end of cancellation module connects power end；The second end of cancellation module is separately connected the output end of photodiode, the first end of current integration module and reseting module；The first end of the third end connection reverse phase amplification module of cancellation module；The second end of reverse phase amplification module is separately connected the second end of current integration module and the first input end of reseting module, the second input terminal input reference voltage of reseting module；Wherein, the voltage of the first input end of reseting module is equal with the voltage of the second input terminal of the reseting module, and reseting module and one unit gain amplifying unit of current integration module composition.Using embodiments herein, it is able to solve and solves the problems, such as that chip area is big in the prior art, noise is big.
Description
Technical field
This application involves range sensor technical field, in particular to a kind of range sensor receive analog front circuit and
Range sensor.
Background technique
Range sensor is generally divided into condenser type and optical profile type two major classes.Wherein, optical distance sensor needs to use
The photoelectric current received is carried out integral and is amplified and converted to voltage by low-noise current-voltage integrator, finally by rear end
Analog-digital converter is converted into digital signal and is handled.In order to inhibit background photo current to lead to the interference of signal in the prior art
Double integrator integrator can be often used, i.e., first the signal comprising background photo current signal and useful signal is integrated, then to only
Signal comprising background photo current signal is integrated, and is finally converted using difference mode signal of the analog-digital converter to the two.
This processing method has the disadvantage in that this meeting firstly, it is necessary to store the analog signal integrated twice respectively with two bulky capacitors
Become very large the area of chip；Secondly as two capacitor needs are worked in a manner of " table tennis ", therefore two capacitors are all
The integrator of the amplifier of biggish switching noise, especially one, two this forms of capacitor can be sampled, the problem is more serious.
Summary of the invention
A kind of range sensor of being designed to provide of the application section Example receives analog front circuit and apart from biography
Sensor, to solve the problems, such as that chip area is big in the prior art, noise is big.
The embodiment of the present application provides a kind of range sensor reception analog front circuit, comprising: photodiode, electric current
Integration module, reverse phase amplification module, the reseting module for being resetted to the current integration module and described for offsetting
The cancellation module of DC component in photodiode background photo current；The first end of the cancellation module connects power end；Institute
The second end for stating cancellation module is separately connected the photodiode, the first end of the current integration module and the reset mould
The output end of block；The third end of the cancellation module connects the first end of the reverse phase amplification module；The reverse phase amplification module
Second end be separately connected the second end of the current integration module and the first input end of the reseting module, the reset mould
Second input terminal input reference voltage of block；Wherein, the voltage of the first input end of the reseting module and the reseting module
The second input terminal voltage it is equal, and the reseting module and one unit gain of current integration module composition amplification are single
Member.
The embodiment of the present application also provides a kind of range sensors, including emission part and receiving unit；The emission part includes
Light emitting diode and driving circuit for driving the light emitting diode；The receiving unit includes Distance-sensing as described above
Device receives analog front circuit and analog-digital converter；The analog-digital converter is connected to the second end of current integration module.
The embodiment of the present application in terms of existing technologies, firstly, current integration module first end and second end it
Between connect reseting module, the reseting module and one unit gain amplifying unit of current integration module composition, in this way, reseting module
The voltage of output end is just equal with the voltage of two input terminal, i.e. the voltage phase of the first end of current integration module and second end
Deng (being equal to the reference voltage), to achieve the purpose that reset current integration module.This reset mode, avoids
In the prior art by the connection switch between the first end and second end of current integration module, and using the switch to electric current product
The process that sub-module is resetted, to reduce switch, bring is non-linear and noise problem.Secondly, an electric current is only arranged
Integration module simplifies the structure of range sensor, is also conducive to reduce the area of range sensor receiving front-end and reduces cost.
In addition, the cancellation module includes sampling capacitance and sampling electronic switch；The input terminal of the sampling electronic switch
It links together with one end of the sampling capacitance, the first end as the cancellation module；The sampling electronic switch
The second end of the output end as the cancellation module；The control terminal of the sampling electronic switch and the sampling capacitance
The other end links together, the third end as the cancellation module.Provide a kind of specific structure of cancellation module.?
The control terminal for sampling electronic switch connects reverse phase amplification module, which can mention for the control terminal of sampling electronic switch
For the voltage (can be since 0) of wider range, in this way, sampling the voltage of the control terminal of electronic switch just in the sampling holding stage
It can change in wider range.Simultaneously as the voltage of the control terminal of sampling electronic switch can change since 0, therefore, if needing
Increase the output electric current of sampling electronic switch, the application embodiment can be by applying in the control terminal of sampling electronic switch
Smaller voltage achieves the goal, and in the prior art can only by be arranged larger size (breadth length ratio is big) sampling electronic switch,
The mutual conductance for increasing sampling electronic switch achieves the goal.And the mutual conductance for sampling electronic switch is bigger, brought noise is bigger, because
This, compared with the existing technology, the settable smaller size of sampling of the application embodiment is electronic switch, is brought to reduce it
Noise.
In addition, the current integration module includes trsanscondutance amplifier and integrating capacitor；The input terminal of the trsanscondutance amplifier
It links together with one end of the integrating capacitor, as the first end of the current integration module, the mutual conductance amplification
The output end of device and the other end of the integrating capacitor link together, the second end as the current integration module.
A kind of specific structure of current integration module is provided.
In addition, the trsanscondutance amplifier specifically includes: the first electronic switch and the second electronic switch；First electronic cutting
The control terminal of pass inputs the first bias voltage, and the input terminal of first electronic switch connects the power end, first electricity
The output end of sub switch and the input terminal of second electronic switch link together, as the described defeated of the trsanscondutance amplifier
Outlet, the input terminal of the control terminal of second electronic switch as the trsanscondutance amplifier, second electronic switch
Output end ground connection.A kind of specific structure of trsanscondutance amplifier is provided.
In addition, the reverse phase amplification module includes reverse phase amplifying unit and the first control switch；First control switch
The first end of the one end as the reverse phase amplification module, the other end of first control switch connects the reverse phase and puts
The output end of big unit, the second end of the input terminal of the reverse phase amplifying unit as the reverse phase amplification module.It provides
A kind of specific structure of reverse phase amplification module.
In addition, the reverse phase amplifying unit is inverting amplifier or broad band amplifier.Two kinds of reverse phase amplifying unit are provided
Implementation.
In addition, the band width of the broad band amplifier is at least 2 times of the gain bandwidth product for sampling holding loop；Wherein, institute
Stating sampling and keeping loop is the cancellation module, the reverse phase amplification module, the current integration module and photosensitive two pole
The loop of pipe composition.
In addition, the broad band amplifier specifically includes: third electronic switch and the 4th electronic switch；The third electronic cutting
The input terminal of pass connects the power end, the control terminal of the third electronic switch, output end and the 4th electronic switch
Input terminal links together, as the output end of the broad band amplifier, described in the control terminal conduct of the 4th electronic switch
The input terminal of broad band amplifier, the output end ground connection of the 4th electronic switch.A kind of specific structure of broad band amplifier is provided.
In addition, the reseting module includes error amplifier and the second control switch；The positive letter of the error amplifier
Number first input end of the input terminal as the reseting module；The non-inverting signal input thereof of the error amplifier is as institute
State second input terminal of reseting module；The output end of the error amplifier connects one end of second control switch,
The output end of the other end of second control switch as the reseting module.The specific knot of one kind of reseting module is provided
Structure.
In addition, the error amplifier specifically includes the 5th electronic switch, the 6th electronic switch, the 7th electronic switch,
Eight electronic switches and the 9th electronic switch；The input terminal of 5th electronic switch connects the power end, the 5th electronics
The control terminal of switch inputs the second bias voltage, and the output end of the 5th electronic switch is separately connected the 6th electronic switch
Input terminal and the 7th electronic switch input terminal；The control terminal of 6th electronic switch is as the error amplifier
The forward signal input terminal, the output end of the 6th electronic switch is separately connected the input of the 8th electronic switch
The control terminal at end, control terminal and nine electronic switch；The control terminal of 7th electronic switch is as the error amplifier
The non-inverting signal input thereof, the input terminal of the output end and the 9th electronic switch of the 7th electronic switch is connected to
Together, as the output end of the error amplifier, the control terminal of the 8th electronic switch connects the 9th electronics
The control terminal of switch, the output end of the 8th electronic switch and the output end of the 9th electronic switch are grounded.It provides and misses
A kind of specific structure of poor amplifier.
The circuit further includes third control switch；The second end of the cancellation module is opened by third control
Connection connects the first end of the current integration module and the output end of the reseting module.
Detailed description of the invention
One or more embodiments are illustrated by the picture in corresponding attached drawing, these exemplary theorys
The bright restriction not constituted to embodiment, the element in attached drawing with same reference numbers label are expressed as similar element, remove
Non- to have special statement, composition does not limit the figure in attached drawing.
Fig. 1 is the structural schematic diagram that analog front circuit is received according to the range sensor of the application first embodiment；
Fig. 2 is the structural schematic diagram according to the current sample phase of the application first embodiment；
Fig. 3 is the structural schematic diagram according to the reset phase of the application first embodiment；
Fig. 4 is the structural schematic diagram according to the current integration phase of the application first embodiment；
Fig. 5 is the working timing figure according to the application first embodiment；
Fig. 6 is the structural schematic diagram according to the analog-to-digital conversion phase of the application first embodiment；
Fig. 7 is the structural schematic diagram according to the trsanscondutance amplifier of the application second embodiment；
Fig. 8 is the structural schematic diagram according to the broad band amplifier of the application second embodiment；
Fig. 9 is the structural schematic diagram according to the error amplifier of the application second embodiment；
Figure 10 is the structural schematic diagram according to the range sensor of the application 3rd embodiment.
Specific embodiment
It is with reference to the accompanying drawings and embodiments, right in order to which the objects, technical solutions and advantages of the application are more clearly understood
The application section Example is further elaborated.It should be appreciated that specific embodiment described herein is only used to solve
The application is released, is not used to limit the application.
The application first embodiment is related to a kind of range sensor reception analog front circuit.As shown in Figure 1, the circuit packet
Include cancellation module 11, reverse phase amplification module 12, reseting module 13, current integration module 14 and photodiode (PD) 15, wherein
Capacitor Cp is the parasitic capacitance inside photodiode 15.The first end of cancellation module 11 connects power supply vdd terminal；Cancellation module 11
Second end be separately connected the first of the cathode of photodiode 15, the output end of reseting module 13 and current integration module 14
End, the plus earth VSS of photodiode 15；The first end of the third end connection reverse phase amplification module 12 of cancellation module 11；Instead
The second end of phase amplification module 12 is separately connected the second end of current integration module 14 and the first input end of reseting module 13, multiple
Second input terminal input reference voltage Vcm of position module 13.
Specifically, the electric current Id that cancellation module 11 exports can be used for offsetting 15 background of photodiode in the present embodiment
Immediate component Ipd in photoelectric current.In one example, which may include sampling capacitance Ch and sampling electronic switch
M0.Wherein, the one end for sampling the input terminal and sampling capacitance Ch of electronic switch M0 links together, as the cancellation module 11
First end；Sample second end of the output end of electronic switch M0 as the cancellation module 11；Sample the control terminal of electronic switch M0
It links together with the other end of sampling capacitance Ch, the third end as the cancellation module 11.It is noted that being in Fig. 1
Illustrated for sampling electronic switch M0 and being PMOS tube, but be not limited thereto, in practical applications, be can also be used
NMOS tube or other electron tubes.
The main function of reverse phase amplification module 12 is voltage (the i.e. electricity of the second end of reverse phase amplification module 12 to input
Pressure) it negates, and it is supplied to sampling electronic switch M0 using negated voltage as bias voltage, to trigger sampling electronic switch
DC component Ipd equal-sized electric current Id of the M0 into the output of photodiode 15 and 15 background photo current of photodiode,
To offset DC component Ipd.In practical applications, reverse phase amplification module 12 may include the control of reverse phase amplifying unit U1 and first
Switch S1；Wherein, first end of the one end of the first control switch S1 as the reverse phase amplification module 12；First control switch S1's
The other end connects the output end of reverse phase amplifying unit U1, the input terminal of reverse phase amplifying unit U1 as reverse phase amplification module 12 the
Two ends.Inverting amplifier can be selected in the reverse phase amplifying unit U1 or broad band amplifier is realized, but considers that broad band amplifier will not be
Circuit introduces new pole, is more advantageous to holding by cancellation module 11, reverse phase amplification module 12, current integration module 14 and photosensitive
The sampling that diode 15 forms keeps the stability of loop, and therefore, the preferred broad band amplifier of the present embodiment amplifies single as reverse phase
First U1.It is noted that when selecting broad band amplifier as reverse phase amplifying unit U1, to guarantee adding for broad band amplifier
Enter, can make entirely to sample holding loop composition close loop negative feedback, the bandwidth of broad band amplifier can be made to be far longer than entire sampling and protected
The gain bandwidth product on support ring road.The bandwidth of the preferred broad band amplifier of the present embodiment is at least the gain bandwidth product for sampling and keeping loop
2 times.
Current integration module 14 is for being converted into voltage for the electric current of input and integrating amplification.In one example, the electricity
Flowing integration module 14 may include trsanscondutance amplifier U3 and integrating capacitor Cf.Wherein, the input terminal of trsanscondutance amplifier U3 and integral electricity
The one end for holding Cf links together, as the first end of current integration module 14, the output end and integral electricity of trsanscondutance amplifier U3
The other end for holding Cf links together, the second end as current integration module 14.
The effect of reseting module 13 is to reset integrating capacitor Cf, keeps the current potential of two pole plates of integrating capacitor Cf equal.This reality
It applies in example, reseting module 13 may include error amplifier U2 and the second control switch S2；Wherein, the positive letter of error amplifier U2
Number input terminal can be used as the first input end of reseting module 13；The non-inverting signal input thereof of error amplifier U2 can be used as reset mould
Second input terminal of block 13；The output end of error amplifier U2 connects one end of the second control switch S2, the second control switch S2
Output end of the other end as reseting module 13.It is noted that the electricity of the forward signal input terminal of error amplifier U2
It presses equal with the voltage of non-inverting signal input thereof, that is, the of the voltage of the first input end of reseting module 13 and reseting module 13
The voltage of two input terminals is equal, is all reference voltage Vcm.
In the present embodiment, the reset loop of reseting module 13 and the composition of current integration module 14 at work, it is poor to constitute one
The unit gain amplifying unit for dividing input, Single-end output, so that the voltage of error amplifier U2 output end and two input terminals are (i.e.
Forward signal input terminal, non-inverting signal input thereof) voltage it is equal, i.e. the current potential of two pole plates of integrating capacitor Cf is equal (all etc.
In reference voltage Vcm), to achieve the purpose that reset integrating capacitor Cf.This reset mode avoids existing skill
By the connection switch between the both ends of integrating capacitor Cf in art, and realization is switched on-off using this, integrating capacitor Cf is carried out
The process of reset, to reduce switch, bring is non-linear and noise problem, so that the linearity of integral is improved, charge
Injection problem is eased.
In addition, the second end of cancellation module 11 can it is noted that the present embodiment may also include third control switch S3
The first end of current integration module 14 and the output end of reseting module 13 are separately connected by third control switch S3.In electric current
Sampling phase resets in phase and current integration phase, and the second end and electric current of cancellation module 11 is connected in third control switch S3
The first end of integration module 14 and the output end of reseting module 13 exist and are equivalent to a conducting wire.And in analog-to-digital conversion phase
In, when ADC (Analog-to-Digital Converter, analog-digital converter) is sampled, third control switch can be disconnected
S3, so that current integration module 14 is inputted without any signal, to improve the accuracy rate of ADC sampling.
Each phase that sensor of adjusting the distance receives analog front circuit is introduced below:
When entering current sample phase (as shown in Figure 2), it can be closed the first control switch S1, and disconnect the second control and open
S2 is closed, at this point, the cancellation module 11, reverse phase amplification module 12, current integration module 14 and photodiode 15 in circuit are constituted
Sampling keeps loop.After the completion of the loop is established, the voltage at the both ends trsanscondutance amplifier U3 is not changing, at this point, not having electric current stream
Cross the parasitic capacitance Cp of integrating capacitor Cf and photodiode 15.In order to offset the direct current in 15 background photo current of photodiode
Component Ipd, reverse phase amplification module 12 negate the trsanscondutance amplifier U3 voltage exported, and using negated voltage as biased electrical
Pressure, be applied to sampling electronic switch M0 control terminal, triggering sampling electronic switch M0 export electric current Id, and electric current Id with it is photosensitive
DC component Ipd in 15 background photo current of diode is equal.Sampling capacitance Ch, which is equivalent to, at this time has sampled in background photo current
DC component Ipd, and be converted into itself voltage.It is noted that due to electric current Id and DC component Ipd phase
Deng, cancel out each other, therefore, in next other phases, electric current Id and DC component Ipd all will not input current integrate mould
In block 14.
It is noted that the control terminal in sampling electronic switch M0 connects reverse phase amplification module 12, which amplifies mould
Block 12 can provide the voltage (voltage can change since 0) of wider range to sample the control terminal of electronic switch M0, in this way, in electricity
Sampling phase is flowed, the voltage for sampling the control terminal of electronic switch M0 can change in wider range.Due to sampling electronic switch
The voltage of the control terminal of M0 can change since 0, therefore, if desired increase the output electric current Id of sampling electronic switch M0, this Shen
Please embodiment can be achieved the goal by applying smaller voltage in the control terminal of sampling electronic switch M0, and in the prior art
Can only be by the sampling electronic switch M0 of selection larger size (breadth length ratio is big), the mutual conductance for increasing sampling electronic switch M0 reaches mesh
's.Since the mutual conductance of sampling electronic switch M0 is bigger, brought noise is bigger, accordingly, with respect to the prior art, this implementation
Smaller size of sampling electronic switch M0 can be selected in example, advantageously reduces the noise that sampling keeps loop.
Then, the first control switch S1 can be disconnected, and is closed the second control switch S2, enters circuit and resets phase (such as
Shown in Fig. 3).At this point, the reseting module 13, current integration module 14 and photodiode 15 in circuit constitute and reset loop.Value
It obtains one and is mentioned that the access of the parasitic capacitance Cp of photodiode 15 can will affect the stability of loop, therefore, in loop stability
Property be affected in the case where, third control switch S3 can also be disconnected, thus disconnect photodiode 15 and reseting module 13 and
The connection of current integration module 14, in this way, reseting module 13 and current integration module 14 just constitute reset loop.This phase
In, error amplifier U2 and current integration module 14 constitute a unit gain amplifying unit, i.e. error amplifier U2 output end
Voltage is equal with the voltage of two input terminals, is equal to reference voltage Vcm.At this point, the current potential of two pole plates of integrating capacitor Cf
Respectively equal (being equal to reference voltage Vcm), to achieve the purpose that reset integrating capacitor Cf.
Then, circuit can be made to carry out current integration phase by disconnecting the first control switch S1 and the second control switch S2
(as shown in Figure 4).As described above, since the flip-flop in 15 background photo current of photodiode is by sampling electronic switch M0
The electric current Id of output is offset.Therefore, in this phase, high fdrequency component only in 15 background photo current of photodiode and apart from biography
The photosignal that light emitting diode (LED) in sensor emission part issues enters in integrating capacitor Cf.In order to further eliminate
High fdrequency component in the background photo current, the present embodiment, can be to the high frequency divisions in background photo current in lumination of light emitting diode
The photosignal of amount and light emitting diode is once integrated, then when light emitting diode extinguishes, then in background photo current
High fdrequency component once integrated, the result integrated twice is subtracted each other in numeric field later, to obtain light emitting diode
Photosignal.
It is carried out specifically, timing diagram as shown in Figure 5 can be used in the current integration phase of the present embodiment.Wherein, sh is to apply
The control signal (when sh is high ordinary mail, the first control switch closure) of the first control switch S1 is added to, rst is to be applied to second
Control signal (when rst is high ordinary mail, the second control switch S2 closure), the led_clk of control switch S2 is luminous to be applied to
Control signal (when led_clk is high ordinary mail, lumination of light emitting diode), the oe of diode are to be applied to third control switch S3
Control signal (oe be high ordinary mail when, third control switch disconnect), dout be analog-to-digital conversion module output signal.This reality
Apply in example, the second end of current integration module 14 for connecting ADC, the ADC can sample rate current integration module 14 integrate twice
Value, and analog-to-digital conversion is carried out to the value of sampling.
As can be seen that the timing diagram is largely divided into two stages, i.e. sh is high flat signal phase and sh is low electric signal
Stage.When sh is high flat signal phase, circuit is in current sample phase, and sampling is 15 background photo current of photodiode
In DC component Ipd.When sh is the low electric signal stage, in a cycle T: first making rst high ordinary mail number, and keep led_
Clk, oe are low level signal, at this point, circuit enters reset phase, integrating capacitor Cf is reset (two pole plates of integrating capacitor Cf
Current potential all be reference voltage Vcm).Then, keeping oe is low level signal, and rst is made to become low ordinary mail from high ordinary mail number
Number, led_clk becomes high ordinary mail number from LOW signal, at this point, circuit enters current integration phase, lumination of light emitting diode, electricity
It flows integration module 14 and carries out first time integral (i.e. the corresponding position A in figure).Then, keeping rst is LOW signal, and makes led_
Clk becomes LOW signal from high ordinary mail number, and oe becomes high ordinary mail number from low level signal, at this point, light emitting diode extinguishes, third
Control switch S3 disconnects (as shown in Figure 6), and circuit enters analog-to-digital conversion phase, and ADC carries out first time sampling, i.e. reading electric current product
Sub-module 14 first time principal value of integral, and the value is subjected to analog-to-digital conversion.When oe is dragged down (failing edge), ADC output is for the first time
Value (i.e. D0) after analog-to-digital conversion.In ADC sampling, third control switch S3 is disconnected, so that current integration module 14 is not appointed
What signal input, keeps output state to be sampled to ADC, advantageously ensures that the accuracy of sampling.
Later, when oe becomes low electric signal, rst changes high ordinary mail number by LOW signal, and circuit is again introduced into reset phase,
Integrating capacitor Cf is reset.After reset, rst is become into LOW signal from high ordinary mail number, and it is low flat for keeping led_clk and oe
Signal, at this point, circuit is again introduced into current integration phase, current integration module 14 carries out second of integral, and (i.e. B is corresponding in figure
Position).Since the two pipe pipes that shine at this time extinguish, current integration module 14 only has the high frequency in 15 background photo current of photodiode
Component input, therefore, second of integral is integrated to the high fdrequency component.After second integrates, oe is again by low level
Become high level, circuit is again introduced into analog-to-digital conversion phase, and ADC carries out second and samples, i.e. reading current integration module 14 the
The value of quadratic integral, and the value is subjected to analog-to-digital conversion.When oe is dragged down, the value after ADC second of analog-to-digital conversion of output is (i.e.
D1)。
Value D1 after subtracting second of analog-to-digital conversion with the value D0 after first time analog-to-digital conversion, can be obtained light emitting diode
It is luminous when photosignal.
As seen in Figure 5, before carrying out analog-to-digital conversion for several times, the present embodiment only needs to carry out primary current and adopts
Sample, when carrying out analog-to-digital conversion, a required signal (i.e. hair for light emitting diode can just be obtained by subtracting each other per the value converted twice
The photosignal of light time).
The present embodiment in terms of existing technologies, firstly, connecting between the first end and second end of current integration module
Reseting module is connect, the reseting module and one unit gain amplifying unit of current integration module composition, in this way, the output of reseting module
The voltage at end is just equal with the voltage of two input terminal, i.e. the first end of current integration module and the voltage of second end is equal
(being equal to the reference voltage), to achieve the purpose that reset current integration module.This reset mode avoids existing
Have by the connection switch between the first end and second end of current integration module in technology, and using the switch to current integration
The process that module is resetted, to reduce switch, bring is non-linear and noise problem.Secondly, an electric current product is only arranged
Sub-module simplifies the structure of range sensor, is also conducive to reduce the area of range sensor receiving front-end and reduces cost.
The second embodiment of the application is related to a kind of range sensor reception analog front circuit.Second embodiment is
The further improvement done on the basis of one embodiment, mainly thes improvement is that, second embodiment provides a kind of mutual conductance amplification
The implementation of device, broad band amplifier and error amplifier.
As shown in fig. 7, trsanscondutance amplifier U3 may particularly include: the first electronic switch M1 and the second electronic switch M2,
In, the control terminal of the first electronic switch M1 is for inputting the first bias voltage (Vbp1)；The input terminal of first electronic switch M1 connects
Connect power supply vdd terminal；The output end of first electronic switch M1 and the input terminal of the second electronic switch M2 link together, as mutual conductance
The output end (Vout1) of amplifier U3；Input terminal (Vin1) of the control terminal of second electronic switch M2 as trsanscondutance amplifier U3；
The output end of second electronic switch M2 is grounded.
As shown in figure 8, broad band amplifier may particularly include: third electronic switch M3 and the 4th electronic switch M4, wherein the
The input terminal of three electronic switch M3 connects power supply vdd terminal；Control terminal, output end and the 4th electronic switch of third electronic switch M3
The input terminal of M4 links together, the output end (Vout2) as broad band amplifier；The control terminal conduct of 4th electronic switch M4
The input terminal (Vin2) of broad band amplifier；The output end of 4th electronic switch M4 is grounded.
As shown in figure 9, error amplifier U2 specifically includes the 5th electronic switch M5, the 6th electronic switch M6, the 7th electronics
Switch M7, the 8th electronic switch M8 and the 9th electronic switch M9；Wherein, the input terminal of the 5th electronic switch M5 connects power vd D
End；The control terminal of 5th electronic switch M5 is for inputting the second bias voltage (Vbp2)；The output end of 5th electronic switch M5 point
It Lian Jie not the input terminal of the 6th electronic switch M6 and the input terminal of the 7th electronic switch M7；The control terminal of 6th electronic switch M6,
As the forward signal input terminal (Vin3+) of error amplifier U2, the output end of the 6th electronic switch M6 is separately connected the 8th electricity
The control terminal of the input terminal of sub switch M8, control terminal and nine electronic switch M9；The control terminal of 7th electronic switch M7, as error
The non-inverting signal input thereof (Vin3-) of amplifier U2；The input of the output end and the 9th electronic switch M9 of 7th electronic switch M7
End links together, the output end (Vout3) as error amplifier U2；The 9th electricity of control terminal connection of 8th electronic switch M8
The control terminal of sub switch M9, the output end of the 8th electronic switch M8 and the output end of the 9th electronic switch M9 are grounded.
It should be noted that being with the first electronic switch M1, third electronic switch M3, the 5th electronic switch in Fig. 7 to 9
M5, the 6th electronic switch M6 and the 7th electronic switch M7 are PMOS tube, the second electronic switch M2, the 4th electronic switch M4, the 8th
Electronic switch M8 and the 9th electronic switch M9 is illustrated for NMOS tube.But in practical application, the first electronic switch M1,
Second electronic switch M2, the 9th electronic switch M9 of third electronic switch M3 ..., can be by field effect transistor or other electronics
Pipe is constituted, which can be PMOS tube or NMOS tube.
In addition, the implementation of trsanscondutance amplifier, broad band amplifier and error amplifier is not limited to the present embodiment and is provided
, in practical applications, it can be put according to the trsanscondutance amplifier, broad band amplifier and the error that need to select other way to realize is realized
Big device, the present embodiment are without limitation.
Present embodiment provides a kind of trsanscondutance amplifier, broad band amplifier and mistake for first embodiment
The implementation of poor amplifier.
The third embodiment of the application is related to a kind of range sensor.As shown in Figure 10, which includes hair
Penetrate portion 101 and receiving unit 102；The emission part 101 includes light emitting diode 1011 and the driving for driving the light emitting diode
Circuit 1012；Receiving unit 102 includes before the range sensor as described in first embodiment or second embodiment receives simulation
The input terminal connection range sensor of terminal circuit 1021 and analog-digital converter 1022, the analog-digital converter 1022 receives AFE(analog front end)
The second end of current integration module in circuit 1021.
Present embodiment in terms of existing technologies, firstly, between the first end and second end of current integration module
Reseting module, the reseting module and one unit gain amplifying unit of current integration module composition are connected, in this way, reseting module is defeated
The voltage of outlet is just equal with the voltage of two input terminal, i.e. the first end of current integration module and the voltage of second end is equal
(being equal to the reference voltage), to achieve the purpose that reset current integration module.This reset mode avoids existing
Have by the connection switch between the first end and second end of current integration module in technology, and using the switch to current integration
The process that module is resetted, to reduce switch, bring is non-linear and noise problem.Secondly, an electric current product is only arranged
Sub-module simplifies the structure of range sensor, is also conducive to reduce the area of range sensor receiving front-end and reduces cost.
It will be understood by those skilled in the art that the various embodiments described above are the specific embodiments of realization the application, and
In practical applications, can to it, various changes can be made in the form and details, without departing from spirit and scope.
Claims (12)
1. a kind of range sensor receives analog front circuit characterized by comprising photodiode, current integration module,
Reverse phase amplification module, reseting module and the counteracting mould for offsetting the DC component in the photodiode background photo current
Block；
The first end of the cancellation module connects power end；The second end of the cancellation module is separately connected photosensitive two pole
The output end of pipe, the first end of the current integration module and the reseting module；The third end of the cancellation module connects institute
State the first end of reverse phase amplification module；The second end of the reverse phase amplification module is separately connected the second of the current integration module
The first input end of end and the reseting module, the second input terminal input reference voltage of the reseting module；
Wherein, the voltage of the first input end of the reseting module is equal with the voltage of the second input terminal of the reseting module,
And the reseting module and the one unit gain amplifying unit of current integration module composition.
2. range sensor according to claim 1 receives analog front circuit, which is characterized in that the cancellation module packet
Include sampling capacitance and sampling electronic switch；
One end of the input terminal and the sampling capacitance of the sampling electronic switch links together, as the cancellation module
The first end；The second end of the output end of the sampling electronic switch as the cancellation module；The sampling electronics
The control terminal of switch and the other end of the sampling capacitance link together, the third end as the cancellation module.
3. range sensor according to claim 1 receives analog front circuit, which is characterized in that the current integration mould
Block includes trsanscondutance amplifier and integrating capacitor；
The input terminal of the trsanscondutance amplifier and one end of the integrating capacitor link together, as the current integration module
The first end, the output end of the trsanscondutance amplifier and the other end of the integrating capacitor link together, as described
The second end of current integration module.
4. range sensor according to claim 3 receives analog front circuit, which is characterized in that the trsanscondutance amplifier
It specifically includes: the first electronic switch and the second electronic switch；
The control terminal of first electronic switch inputs the first bias voltage, described in the input terminal connection of first electronic switch
Power end, the output end of first electronic switch and the input terminal of second electronic switch link together, as described
The output end of trsanscondutance amplifier, the input of the control terminal of second electronic switch as the trsanscondutance amplifier
End, the output end ground connection of second electronic switch.
5. range sensor according to claim 1 receives analog front circuit, which is characterized in that the reverse phase amplifies mould
Block includes reverse phase amplifying unit and the first control switch；
The first end of the one end of first control switch as the reverse phase amplification module, first control switch
The other end connects the output end of the reverse phase amplifying unit, and the input terminal of the reverse phase amplifying unit amplifies mould as the reverse phase
The second end of block.
6. range sensor according to claim 5 receives analog front circuit, which is characterized in that the reverse phase amplification is single
Member is inverting amplifier or broad band amplifier.
7. range sensor according to claim 6 receives analog front circuit, which is characterized in that the broad band amplifier
Bandwidth be at least and sample 2 times of gain bandwidth product that keep loop；Wherein, it is the counteracting mould that the sampling, which keeps loop,
The loop that block, the reverse phase amplification module, the current integration module and the photodiode form.
8. range sensor according to claim 6 or 7 receives analog front circuit, which is characterized in that put in the broadband
Big implement body includes: third electronic switch and the 4th electronic switch；
The input terminal of the third electronic switch connects the power end, the control terminal of the third electronic switch, output end and
The input terminal of 4th electronic switch links together, as the output end of the broad band amplifier, the 4th electronic cutting
Input terminal of the control terminal of pass as the broad band amplifier, the output end ground connection of the 4th electronic switch.
9. range sensor according to claim 1 receives analog front circuit, which is characterized in that the reseting module packet
Include error amplifier and the second control switch；
The first input end of the forward signal input terminal of the error amplifier as the reseting module；The error is put
Second input terminal of the non-inverting signal input thereof of big device as the reseting module；The output end of the error amplifier connects
Connect one end of second control switch, the output of the other end of second control switch as the reseting module
End.
10. range sensor according to claim 8 receives analog front circuit, which is characterized in that the error amplification
Implement body includes the 5th electronic switch, the 6th electronic switch, the 7th electronic switch, the 8th electronic switch and the 9th electronic switch；
The input terminal of 5th electronic switch connects the power end, and the control terminal input second of the 5th electronic switch is partially
Voltage is set, the output end of the 5th electronic switch is separately connected the input terminal and the 7th electronics of the 6th electronic switch
The input terminal of switch；The forward signal input terminal of the control terminal of 6th electronic switch as the error amplifier,
The output end of 6th electronic switch is separately connected input terminal, control terminal and nine electronic cutting of the 8th electronic switch
The control terminal of pass；The non-inverting signal input thereof of the control terminal of 7th electronic switch as the error amplifier, institute
The input terminal for stating the output end and the 9th electronic switch of the 7th electronic switch links together, as the error amplifier
The output end, the control terminal of the 8th electronic switch connects the control terminal of the 9th electronic switch, the 8th electricity
The output end of the output end of sub switch and the 9th electronic switch is grounded.
11. range sensor according to claim 1 receives analog front circuit, which is characterized in that the circuit also wraps
Include third control switch；
The second end of the cancellation module connects described the of the current integration module by the third control switch
The output end of one end and the reseting module.
12. a kind of range sensor, which is characterized in that including emission part and receiving unit；The emission part includes light emitting diode
And the driving circuit for driving the light emitting diode；The receiving unit includes such as any one of claim 1 to 11 institute
The range sensor stated receives analog front circuit and analog-digital converter；The analog-digital converter is connected to current integration module
Second end.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/CN2018/097880 WO2020024122A1 (en) | 2018-08-01 | 2018-08-01 | Proximity sensor receiving analog front-end circuit and proximity sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109075755A true CN109075755A (en) | 2018-12-21 |
| CN109075755B CN109075755B (en) | 2020-05-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201880001032.XA Active CN109075755B (en) | 2018-08-01 | 2018-08-01 | Distance sensor receiving analog front-end circuit and distance sensor |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN109075755B (en) |
| WO (1) | WO2020024122A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2020024122A1 (en) * | 2018-08-01 | 2020-02-06 | 深圳市汇顶科技股份有限公司 | Proximity sensor receiving analog front-end circuit and proximity sensor |
| CN117110692A (en) * | 2023-10-24 | 2023-11-24 | 武汉市聚芯微电子有限责任公司 | Current integrating circuit, photo-generated current reading circuit and chip |
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| CN102645451A (en) * | 2012-04-26 | 2012-08-22 | 中国科学院微电子研究所 | Current type signal detection analog front-end circuit |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2020024122A1 (en) * | 2018-08-01 | 2020-02-06 | 深圳市汇顶科技股份有限公司 | Proximity sensor receiving analog front-end circuit and proximity sensor |
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- 2018-08-01 CN CN201880001032.XA patent/CN109075755B/en active Active
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| CN102645451A (en) * | 2012-04-26 | 2012-08-22 | 中国科学院微电子研究所 | Current type signal detection analog front-end circuit |
| CN104545873A (en) * | 2014-12-31 | 2015-04-29 | 中国科学院深圳先进技术研究院 | Photocurrent processing analog front-end circuit for photoelectric volume description signals |
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| CN117110692B (en) * | 2023-10-24 | 2024-01-12 | 武汉市聚芯微电子有限责任公司 | Current integrating circuit, photo-generated current reading circuit and chip |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2020024122A1 (en) | 2020-02-06 |
| CN109075755B (en) | 2020-05-12 |
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