CN216433240U

CN216433240U - APD signal processing circuit for space light measuring equipment

Info

Publication number: CN216433240U
Application number: CN202220039852.1U
Authority: CN
Inventors: 刘肃超
Original assignee: Shenzhen Zhongzhijia Electronics Co ltd
Current assignee: Shenzhen Zhongzhijia Electronics Co ltd
Priority date: 2022-01-04
Filing date: 2022-01-04
Publication date: 2022-05-03
Anticipated expiration: 2032-01-04

Abstract

The utility model discloses a APD signal processing circuit for space light measuring equipment, include APD current-limiting protection circuit along APD signal transmission direction in proper order, JFET-TIA transimpedance amplifier circuit, back level collector triode amplifier circuit and impedance matching circuit altogether, APD Sensor signal is through APD current-limiting protection circuit output, at first convert current signal to voltage signal through JFET-TIA transimpedance amplifier circuit, enlarge voltage signal through back level collector triode amplifier circuit altogether, do impedance matching ac coupling output through impedance matching circuit at last. The utility model discloses can be applied to pulse range sensor and laser radar, the photoelectric conversion current signal of mainly handling avalanche diode converts weak current signal into voltage signal, compromises highlight pulse signal and weak light pulse signal simultaneously and can both be effectively discerned, under the prerequisite of guaranteeing the pulse distortionless, reduces circuit consumption, cost, volume.

Description

APD signal processing circuit for space light measuring equipment

Technical Field

The utility model relates to a APD signal processing technology field of space light measuring equipment, concretely relates to APD signal processing circuit for space light measuring equipment.

Background

At present, most APD (avalanche photo diode) signal processing of space optical measurement equipment (laser radar and ranging sensor) adopts an integrated IC (integrated circuit) single-path/multi-path transimpedance operational amplifier/transimpedance operational amplifier, so that the cost is high, the power consumption is large, the circuit volume is advantageous, the single-path cost is about 30RMB approximately, and the power consumption is 5V/14-20 mA. The area of a conventional PCB of a single IC + peripheral circuit is 4x4mm, and the 3x3mm can be achieved by adopting a small package, such as: the power consumption of the OPA855/858 of TI is 60mW, the power consumption of the ADI LTC6561/6563 is 4 paths of 200 mW/equivalent single path of 50mW, and the power consumption of the MAXIM MAX40662 is 90 mW. The few triode radio frequency amplifying circuits have large single-path power consumption, typical power consumption is 7V/30-40 mA and 5V/30-40 mA, a triode scheme with excellent performance can ensure that when input photoelectric pulses are saturated and widened, signals are not trailing and overshot, photoelectric conversion gain is in the magnitude of 105V/W, when input photoelectric pulses with poor performance are saturated and widened, signals are trailing and overshot, the circuit cost is about 10RMB, and the area of a conventional PCB is in the range of 6x6 mm-4 x4mm, such as: a typical bandwidth of a KY-APRM-BW-I-FS APD photoelectric sensor module with photoelectric characteristics is 200 MHz/whole module power consumption 1200mW, and partial APD circuit power consumption 430 mW.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome prior art's not enough, provide a APD signal processing circuit for space light measuring equipment.

The technical scheme of the utility model as follows:

an APD signal processing circuit for space optical measurement equipment sequentially comprises an APD current-limiting protection circuit, a JFET-TIA trans-resistance amplification circuit, a rear-stage common collector triode amplification circuit and an impedance matching circuit along the transmission direction of APD signals, wherein APD Sensor signals are output through the APD current-limiting protection circuit, firstly current signals are converted into voltage signals through the JFET-TIA trans-resistance amplification circuit, then the voltage signals are amplified through the rear-stage common collector triode amplification circuit, and finally impedance matching alternating current coupling output is conducted through the impedance matching circuit.

Further, the APD current-limiting protection circuit comprises an APD bias voltage input interface J3 and a current-limiting resistor R1, wherein the APD bias voltage input interface J3 is connected with the JFET-TIA transimpedance amplifier circuit through the current-limiting resistor R1.

Further, the transimpedance gain of the JFET-TIA transimpedance amplification circuit is 1-20K omega.

Further, the JFET-TIA transimpedance amplification circuit sequentially comprises an APD, an avalanche diode D1, an alternating current signal coupler C22 and a current-to-voltage negative feedback amplification circuit along the transmission direction of the APD signal.

Further, the current-to-voltage negative feedback amplifying circuit is composed of a triode Q4, a triode Q1 and a cross-over resistor R9, the alternating current signal coupler C22 is connected with the B-stage of the triode Q4, the C-stage of the triode Q4 is connected with the B-stage of the triode Q1, and the cross-over resistor R9 is connected between the E-stage of the triode Q4 and the E-stage of the triode Q1.

Furthermore, the rear-stage common collector triode amplifying circuit is connected with a voltage signal in an input alternating current signal coupling mode.

Further, the rear-stage common-collector triode amplifying circuit sequentially comprises an alternating current coupler C61, a first-stage amplifying triode Q9, an alternating current coupler C62 and a second-stage amplifying triode Q10 along the voltage signal transmission direction.

Further, after the voltage signal is amplified, the voltage signal is output by 50 omega impedance matching alternating current coupling through the impedance matching circuit.

Compared with the prior art, the beneficial effects of the utility model reside in that: the utility model discloses can be applied to pulse range sensor and laser radar, mainly handle the photoelectric conversion current signal of avalanche diode (APD), convert weak current signal into voltage signal, compromise highlight pulse signal and weak light pulse signal simultaneously and can both be effectively discerned, under the prerequisite of guaranteeing the pulse distortionless, reduce circuit consumption, cost, volume.

1. The utility model ensures the excellent performance of the preceding stage amplifying circuit, 400MHz/2K transimpedance gain;

2. the utility model solves the problem of large single-stage power consumption of TIA, the single-stage TIA is only 17.5mW, the total power consumption of post-amplification is 87.5mWmax, the key performance index can be aligned with the integrated IC scheme, and the low power consumption is beneficial to the miniaturization of the multi-line radar;

3. the utility model has the advantages that the occupied area of the circuit is almost the same as that of the integrated IC scheme, but the circuit has great advantages compared with other triode schemes in the market, and the circuit can be considered to be integrated into a multi-channel transimpedance amplifier IC flow sheet after being stabilized, thereby being beneficial to the technical optimization of the laser radar industry;

4. the utility model provides an integrated IC scheme problem with high costs, the low cost is favorable to multi-thread laser radar scheme to promote scanning line number and image point cloud density, further promotes laser radar technical upgrade, does super high line number, super high point cloud density product.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a circuit block diagram of an APD signal processing circuit for a spatial light measuring device provided by the present invention;

fig. 2 is a schematic circuit diagram of an APD current limiting protection circuit according to the present invention;

fig. 3 is a schematic circuit diagram of the JFET-TIA transimpedance amplifier circuit of the present invention;

fig. 4 is a schematic circuit diagram of the rear-stage common-collector triode amplifier circuit according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention.

In order to explain the technical solution of the present invention, the following description is made by using specific examples.

Examples

Referring to fig. 1, the present embodiment provides an APD signal processing circuit for spatial light measurement equipment, which sequentially includes an APD current-limiting protection circuit, a JFET-TIA transimpedance amplifier circuit, a post-stage common-collector triode amplifier circuit, and an impedance matching circuit along an APD signal transmission direction. The circuit principle is as follows: the APD Sensor signal is output through an APD current-limiting protection circuit, firstly a current signal is converted into a voltage signal through a JFET-TIA trans-resistance amplifying circuit, then the voltage signal is amplified through a rear-stage common collector triode amplifying circuit, and finally 50 omega impedance matching alternating current coupling output is carried out through an impedance matching circuit, the output signal can be directly identified by an ADC analog-to-digital signal chip of a ranging system and converted into a digital time domain signal, or can be directly converted into a TTL level through a first-stage comparator and identified by an FPGA or a TDC time measurement chip.

Because the utility model discloses mainly apply to open space optical measurement, any open space optical measurement can't guarantee that input light intensity does not exceed measuring range, and the highlight is amazing to the damage of APD is permanent, consequently can avoid when the highlight is incident through APD current-limiting protection circuit, and the APD electric current transships, is damaged by the heavy current, as shown in fig. 2, APD current-limiting protection circuit includes APD bias voltage input interface J3 and current-limiting resistor R1, and APD bias voltage input interface J3 passes through current-limiting resistor R1 and connects JFET-TIA transimpedance amplifier circuit.

The transimpedance gain of the JFET-TIA transimpedance amplifier circuit is 1-20K omega adjustable, the typical bandwidth is 400MHz (2K omega gain), the practical application can be adjusted according to the laser intensity received by an APD (avalanche photo diode) and the APD light-sensitive surface, and the larger the transimpedance gain is, the better the transimpedance gain is on the premise of not influencing the bandwidth of the amplifier circuit in principle. As shown in fig. 3, the JFET-TIA transimpedance amplifier circuit sequentially includes an APD, an avalanche diode D1, an ac signal coupler C22, and a current-to-voltage negative feedback amplifier circuit along the APD signal transmission direction, the transistor Q4, the transistor Q1, and the bridge resistor R9 form the current-to-voltage negative feedback amplifier circuit, the ac signal coupler C22 is connected to the B-stage of the transistor Q4, the C-stage of the transistor Q4 is connected to the B-stage of the transistor Q1, and the bridge resistor R9 is connected between the E-stage of the transistor Q4 and the E-stage of the transistor Q1. Weak space pulse optical signals are converted into narrow pulse current signals through APDs, a direct current path is provided for an avalanche diode D1, the current signals are input into a B level of a triode Q4, current amplification is carried out, and then the current signals are sent into a triode Q1, the larger the transimpedance of a bridging resistor R9 is, the higher the circuit gain is, the larger the amplitude of signals output by an E level of a triode Q1 is, but the bandwidth of the passing frequency can be reduced in an equal proportion. After the model of the triode Q4 and the model of the triode Q1 are selected, the frequency characteristic is basically fixed, and the circuit bandwidth can be calculated according to the model selection parameters. The TIA signal at the output end is a converted voltage signal which can be used for subsequent circuit processing, and can also be directly measured by being connected into a 50 omega impedance matching channel of an oscilloscope in an alternating current coupling mode. When the signal is processed to this step, the photoelectric gain is not large enough, and the signal can be continuously amplified, so as to achieve better signal-to-noise ratio and signal resolution.

Because the circuit is applied to space light measuring equipment (laser radar and a distance measuring sensor), distance measuring laser lights are irradiated on a measured object, the measured object has different laser reflectivity, the optical pulse signals input each time cannot be ensured to be in a normal receiving range, in order to avoid overlarge APD current signals caused by strong light signal saturation, a high-speed MOS tube M2 is introduced, when the APD current signals are increased and pass through a R50/R51 direct current path, a voltage difference is generated, a G stage of the M2 tube is rapidly opened, large current is rapidly discharged into a signal ground from the M2 until the voltage drop of R51 is not enough to open the M2 tube, and the tube is automatically closed, so that the small signal amplification capability of the circuit is ensured.

The partial circuit is applied to laser radar space light detection for the first time, the occupied area is about 5x5mm, and the power consumption is 5V/2.5-3.5 mA and 17.5 mWmax. The material cost is less than 2RMB without the photodiode APD.

Further, as shown in fig. 4, the rear-stage common-collector triode amplifying circuit is coupled to a voltage signal in an input ac signal coupling manner, and the rear-stage common-collector triode amplifying circuit sequentially includes an ac coupler C61, a first-stage amplifying triode Q9, an ac coupler C62, and a second-stage amplifying triode Q10 along a voltage signal transmission direction. The input signal is coupled through an AC coupler C61, amplified through a first-stage amplifying triode Q9, coupled through an AC coupler C62 and amplified through a second-stage amplifying triode Q10, and finally subjected to photoelectric conversionGain is about 9x10⁵The detailed calculation is the basic calculation of the electronic circuit and is not described in detail here. The area of the circuit occupying board is about 3x7mm, and the power consumption is 5V/13-14 mA, 70 mWmax. The material cost is less than 2 RMB.

The utility model discloses a triode transimpedance amplifier circuit, preceding stage transimpedance gain are 1K omega ~ 20K omega adjustable, and the back level is two collecting electrode triode amplifier circuits altogether, and every level of gain is 7V/V, and maximum gain is 48V/V, and final photoelectric gain can accomplish 9x10⁵V/W, the final voltage noise is 40 mVpp. The following problems are mainly solved:

1. referring to the prior TIA technical performance, on the premise of ensuring 400MHz bandwidth, the front-stage transimpedance gain is not lower than 2K omega, and the rear-stage amplification gain is not lower than 48 times;

2. the problem of large power consumption of a triode amplifying circuit is solved, and the power consumption is in the same power consumption level as TIA (integrated operational amplifier), and is not more than 90 mW;

3. the problem that the current triode amplifying circuit occupies a large area of a panel is solved;

4. the problem that the cost of the current TIA scheme including an integrated IC and a triode is high is solved.

The above description is only exemplary of the present invention and should not be construed as limiting the present invention, and any modifications, equivalents and improvements made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

1. An APD signal processing circuit for a spatial light measurement device, characterized by: the APD current-limiting protection circuit, the JFET-TIA transimpedance amplifier circuit, the rear-stage common collector triode amplifier circuit and the impedance matching circuit are sequentially arranged along the APD signal transmission direction, an APD Sensor signal is output through the APD current-limiting protection circuit, the current signal is converted into a voltage signal through the JFET-TIA transimpedance amplifier circuit, the voltage signal is amplified through the rear-stage common collector triode amplifier circuit, and finally impedance matching alternating current coupling output is conducted through the impedance matching circuit.

2. The APD signal processing circuit for an aerial optical measurement device of claim 1, wherein: the APD current-limiting protection circuit comprises an APD bias voltage input interface J3 and a current-limiting resistor R1, wherein the APD bias voltage input interface J3 is connected with a JFET-TIA transimpedance amplification circuit through the current-limiting resistor R1.

3. The APD signal processing circuit for an aerial optical measurement device of claim 1 or 2, wherein: the transimpedance gain of the JFET-TIA transimpedance amplification circuit is 1-20K omega.

4. The APD signal processing circuit for a spatial light measurement device of claim 3, wherein: the JFET-TIA transimpedance amplification circuit sequentially comprises an APD, an avalanche diode D1, an alternating current signal coupler C22 and a current-to-voltage negative feedback amplification circuit along the transmission direction of an APD signal.

5. The APD signal processing circuit for an aerial optical measurement device of claim 4, wherein: the current-to-voltage negative feedback amplifying circuit is composed of a triode Q4, a triode Q1 and a cross-over resistor R9, the alternating current signal coupler C22 is connected with the B level of the triode Q4, the C level of the triode Q4 is connected with the B level of the triode Q1, and the cross-over resistor R9 is connected between the E level of the triode Q4 and the E level of the triode Q1.

6. The APD signal processing circuit for an aerial optical measurement device of claim 1, wherein: the rear-stage common collector triode amplifying circuit is connected with a voltage signal in an input alternating current signal coupling mode.

7. The APD signal processing circuit for an aerial optical measurement device of claim 6, wherein: the rear-stage common-collector triode amplifying circuit sequentially comprises an alternating current coupler C61, a first-stage amplifying triode Q9, an alternating current coupler C62 and a second-stage amplifying triode Q10 along the voltage signal transmission direction.

8. The APD signal processing circuit for an aerial optical measurement device of claim 1, wherein: and after the voltage signal is amplified, the 50-omega impedance matching alternating current coupling output is carried out through the impedance matching circuit.