Anti-interference low-power dissipation system for multiple spot laser ranging
Technical field
The present invention relates to integrated circuit laser ranging fields, more particularly to one kind to be suitable for the laser ranging of intelligent automobile multiple spot
The low-power consumption of system, strong interference immunity system structure.Concretely relate to the anti-interference low-power consumption system for multiple spot laser ranging
System.
Background technique
In recent years, Development of Laser Technology is rapid, and a series of application of deriving technologies relevant to laser also reaches its maturity,
In most it is representational be laser ranging technique and relative laser radar application.Laser ranging technique benefit
High brightness and strong coherence with laser, can accurately measure object distance.The application of laser radar is in Laser Measuring
Away from technical, the grayscale informations such as profile further integrated relevant information, and then obtain object can be applied to automobile intelligent
In driving, being unmanned.
The range measurement principle that laser ranging technique is widely used is time-of-flight method (TOF, time of flight), and TOF is logical
The time difference for differentiating laser pulse initial signal and echo-signal is spent, the flight time of light beam is obtained, to be calculated in conjunction with the light velocity
Laser emitter is the distance between to object out.The range accuracy of TOF is mainly by range-measurement system for starting (START) and end
Only the discrimination precision of (STOP) timing signal determines.Measurement distance is given by: (wherein c is the light velocity, and t, which is that laser is total, to fly
The row time)
In intelligent automobile application field, intelligence assists driving technology to need in a short time to the multiple angles of vehicle periphery
Barrier that may be present carries out ranging, and then planning travelling line.Utilize mechanical scanning type laser radar or all-solid state laser
This target, but higher cost may be implemented in radar.The light that conventional front-end reading circuit structure usually generates detector simultaneously
It after electric current conversion amplification, is converted through analog-digital converter (ADC), is sent into host computer using related algorithm and carries out data processing, obtain
Range information.The conversion accuracy of ADC directly affects range accuracy, and the power consumption of high-precision adc is generally larger, higher cost.
This patent proposes the laser ranging system structure of a kind of low-power consumption, strong interference immunity, only to being related to several passes of traffic route
Bond angle degree carries out ranging, while in the processing of data, avoids the dependence to ADC, by being followed by comparator and whole in TIA
Shape, direct output difference digital signal, as STOP signal, improve anti-interference energy of the signal in transmission process to host computer
Power.
Summary of the invention
In order to overcome the deficiencies of the prior art, the present invention is directed to propose it is a kind of suitable for intelligent automobile based on time-of-flight method
Low-power consumption, overall power is effectively reduced in the multiple spot laser ranging system structure of strong interference immunity, while having at low cost, resists
The strong advantage of interference.For this reason, the technical scheme adopted by the present invention is that the anti-interference low-power consumption system for multiple spot laser ranging
System, by photocurrent detection device, front end reading circuit, trans-impedance amplifier TIA, comparator, multiple selector, host computer MCU, high pressure
Biasing circuit composition, host computer MCU generate channel enable signal Control, and control HVB high voltage bias circuit is photoelectric current spy first
It surveys device and bias is provided, photocurrent detection device is started to work under the action of HVB high voltage bias module, detects optical signal, generates electric current arteries and veins
It rushes signal to be input in the reading circuit of front end, after being enlarged into voltage signal via TIA, make comparisons with a reference voltage Vref,
It is converted into differential digital signal output by comparator, then is transmitted to multiple selector through M signal transmission line;MCU is sent
Control signal Control synchronously control multiple selector, gate corresponding channel, the data of respective channel read, via MCU
After processing calculates, the range information in channel all the way is exported, and so on, complete the output of the range information in any channel.
The data path in different channels will not work at the same time, and be switched by PC control TIA across resistance, when stopping ranging,
It is in close state.
Control signal is M BITBUS network signal, and specific digit M is determined by required port number, needs to meet:
2M≥N
Wherein N is number of active lanes.
The features of the present invention and beneficial effect are:
Since system uses the operating mode of single channel gating, power consumption is effectively reduced.System is straight using front-end circuit
It connects the progress line transmission of output difference digital signal and improves signals transmission while eliminating by ADC bring power consumption
In anti-interference ability.Multi-direction obstacle detection is realized using multiple point distance measurement scheme, structure is relatively simple, and cost is relatively low, function
Consume low, anti-interference is stronger.
Detailed description of the invention:
Fig. 1 TOF measurement schematic illustration.
Fig. 2 multiple spot laser ranging schematic diagram.
Specific embodiment
Multiple spot laser ranging system structure proposed by the present invention realizes crucial direction first with multiple single-point laser rangings
Distance detection, then by detector front end reading circuit, through trans-impedance amplifier (TIA, transimpedance
Amplifier) and after comparator direct output difference digital signal, the STOP signal as TOF measurement send host computer progress back to
The judgement of echo moment, eliminates analog-digital converter, while effectively reducing the overall power of system.
Fig. 2 is multiple spot laser distance measuring principle schematic diagram proposed by the present invention, and the structure is mainly by photocurrent detection device, across resistance
The modules such as amplifier, comparator, multiple selector, host computer MCU, HVB high voltage bias circuit composition.
System work process is as follows, and host computer MCU generates channel enable signal Control, first control HVB high voltage bias mould
Block provides bias for photocurrent detection device, and photocurrent detection device is started to work under the action of HVB high voltage bias module, detection light letter
Number, it generates current pulse signal and is input in the reading circuit of front end, after being enlarged into voltage signal via TIA, with one with reference to electricity
Pressure Vref makes comparisons, and is converted into differential digital signal output by comparator, then be transmitted to multichannel through M signal transmission line
Selector.The control signal Control synchronously control multiple selector that MCU is sent at this time, gates corresponding channel (Channel)
The data for reading respective channel handle after calculating via MCU, export the range information in channel all the way.And so on, it completes any
The output of the range information in channel.Since the data path in different channels will not work at the same time, system power dissipation further reduced.
By PC control TIA across resistance switch, when stopping ranging, be in close state, prevented TIA mistake output voltage pulse can
Energy property, improves system reliability.Control signal is M BITBUS network signal in schematic diagram, and specific digit M is by required
Port number determines, needs to meet:
2M≥N
Wherein N is number of active lanes.
Single channel adds the structure of comparator to complete detection under PC control adjusting after using TIA, single channel output
Differential signal, to host computer, is further processed through the multi-channel gating device gating output under PC control.TIA, comparator
With detector close to placing, multiple selector should be with host computer MCU close to placement, wherein between comparator and multiple selector
Line is longer, and the anti-interference ability in transmission process is improved using differential transfer.Protection scope of the present invention is not with above-mentioned
Embodiment is limited, and those of ordinary skill in the art's equivalent modification or variation made by disclosure according to the present invention is all answered
It is included in protection scope.