CN216621535U

CN216621535U - Temperature calibration device for 5G communication optical module

Info

Publication number: CN216621535U
Application number: CN202122258264.5U
Authority: CN
Inventors: 潘冬
Original assignee: Chengdu Rongbo Communication Technology Co ltd
Current assignee: Chengdu Rongbo Communication Technology Co ltd
Priority date: 2021-09-17
Filing date: 2021-09-17
Publication date: 2022-05-27
Anticipated expiration: 2031-09-17

Abstract

The utility model discloses a temperature calibration device for a 5G communication optical module, which comprises a microprocessor, at least two optical module sockets, a temperature probe array and a sampling shaping circuit. The mode of adopting the temperature probe array can be used for measuring the temperature of different parts on the optical module, can realize the temperature calibration of higher accuracy, and also has certain production efficiency.

Description

Temperature calibration device for 5G communication optical module

Technical Field

The utility model relates to a temperature calibration device for a 5G communication optical module, in particular to a calibration device for the shell temperature of a DSFP optical module for 5G communication, and belongs to the technical field of optical communication.

Background

Whether a core device Laser of the DSFP optical module is a Fabry-perot (FP for short), a Distributed feedback Laser (DFB for short) and a Vertical-Cavity Surface-Emitting Laser (VCSEL for short) are both temperature-dependent, and the wavelength and power of the Laser are affected by the operating temperature.

Five physical quantities for dynamic monitoring of the DSFP optical module include a module Temperature, which generally requires to acquire an optical module shell Temperature as a reported Temperature, in practical application, a Temperature value of a Temperature sensor of a microprocessor inside the optical module is often used as the reported Temperature, but the Temperature sensor is generally built in a core of the microprocessor, so the Temperature is a core Temperature (Die Temperature), in addition, drivers in the optical module generate different heat, Digital Signal Processors (DSPs) generate different heat effects, and the heat distribution in the whole optical module is uneven, if the core Temperature of the Temperature sensor is used as a monitoring quantity reporting system, an error is large, so a DSFP optical module manufacturer needs to calibrate the Temperature of the DSFP optical module in a production process.

There are two methods currently in common use:

firstly, adopting a high-low temperature box: the monitoring temperature of the DSFP optical modules is calibrated by the test temperature of the high-low temperature box, the method has the advantages of low cost and more DSFP optical modules calibrated at one time, and the method has the defects that the high-low temperature box has larger space and different heat distribution, the difference between the display temperature of the high-low temperature box and the actual temperature of each DSFP optical module is larger, the heat distribution of the heat effect is different, and the error is larger.

Secondly, adopting a heat flow meter: the temperature is set by the heat flow meter to calibrate the monitoring temperature of the DSFP optical module, and the heat flow is to align the air flow of the temperature to the DSFP optical module, so the scheme has the advantages of accurately reflecting the shell temperature of the DSFP optical module, and has the defects that the space size of a heat flow cover of the heat flow meter is very small, the calibration of only one DSFP optical module can be ensured, and the calibration efficiency is low.

Among the prior art, for solving the deviation of high and low temperature case collection temperature and optical module actual temperature, utility model patent that publication number is CN207964128U discloses an optical module temperature calibration platform and system, carry out actual measurement to the casing temperature of high and low temperature incasement optical module through the temperature probe and obtain actual measurement temperature, compare and the fitting with the optical module nuclear internal temperature that test platform tested again, thereby realize calibrating the nuclear internal temperature of optical module according to actual measurement casing temperature, improve the detection accuracy of the operating temperature to optical module, thereby reach the mesh of guaranteeing that the optical module is qualified to dispatch from the factory. In addition, the utility model patent with publication number CN109443598A also discloses an optical module temperature calibration method and device, which obtains the average temperature of the optical module to be tested after the temperature is stable through a temperature measurement module and test software, writes the stable average temperature into a corresponding calibration register through the test software to calibrate the temperature, and compares whether the measured average temperature and the calibrated reported temperature meet the specified temperature deviation requirement, so as to quickly realize the automatic calibration of the reported temperature of the optical module, thereby improving the accuracy and reliability of the reported temperature of the optical module.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a temperature calibration device for a 5G communication optical module, which can be used for measuring the temperature of different parts on the optical module by adopting a temperature probe array mode, can realize high-precision temperature calibration and has certain production efficiency.

The utility model is realized by the following technical scheme: a temperature calibrating device for 5G communication optical module, including microprocessor, two at least optical module sockets, temperature probe array and sampling shaping circuit, microprocessor is equipped with the interface circuit who is connected with the host computer, and the optical module passes through the optical module socket and connects microprocessor, and the temperature probe array comprises two at least temperature probes of locating on every optical module, and temperature probe passes through sampling shaping circuit and connects microprocessor.

The sampling shaping circuit comprises a sampling holding circuit, a filter circuit and a voltage conditioning circuit which are connected in sequence, and analog signals collected by the temperature probe are sent to an ADC port of the microprocessor through the sampling holding circuit, the filter circuit and the voltage conditioning circuit in sequence.

The sampling shaping circuit also comprises a plurality of precision resistors with different resistance values, which are connected in parallel between the temperature probe and the sampling holding circuit, and a change-over switch controlled by a microprocessor is arranged between each precision resistor and the temperature probe.

And two temperature probes arranged on each optical module are respectively and correspondingly arranged at the positions of the laser and the working chip in the optical module.

The working chip is a driver or a digital signal processor.

The number of the optical module sockets is four, and the temperature probe array is composed of 4 multiplied by 2 temperature probes.

The Temperature probe is an NTC (Negative Temperature Coefficient, NTC for short) probe.

Compared with the prior art, the utility model has the following advantages and beneficial effects:

(1) aiming at the DSFP optical module, the PAM4 technology is used, the requirement on temperature precision is higher than that of the traditional low-rate SFP, SFP + and XFP, meanwhile, the working temperature range of the DSFP optical module is large, the working in the whole temperature range is ensured, the temperature must be calibrated in the production process, particularly, the internal temperature of the DSFP optical module has the condition of different heat distribution, and the problems of precision and production efficiency exist no matter a heat flow meter or a high-low temperature box is used for calibrating the temperature in the production of the current DSFP optical module. In order to solve the technical problems, the NTC probe array mode is adopted, the temperature of a plurality of optical modules and main heat distribution positions (a laser, a digital signal processor and a laser driving chip) on the optical modules can be sampled, the temperature value is averaged by a microprocessor, high-precision temperature calibration can be realized, and certain production efficiency can be considered.

(2) In order to meet the calibration work of the DSFP optical module in the full temperature range, the utility model needs to adopt a sampling shaping circuit to ensure that the analog signal conversion sampled by the NTC probe is more accurate, and the method comprises the following steps:

A. connecting high-precision resistors, and enabling the microprocessor to select different high-precision resistors to be connected into the holding circuit according to the temperature so as to ensure the sampling accuracy of each temperature section and the ADC sampling accuracy of the whole temperature range;

B. by adopting a filter circuit such as a low-pass filter, various interference sources such as power frequency interference of the temperature cycle box and DC/DC high-frequency interference of a power supply of the calibration device when the NTC probe samples in the temperature cycle box can be avoided;

C. and a voltage conditioning circuit is adopted for isolating signals and reducing interference so as to protect the function of an ADC (analog to digital converter) port of the microprocessor.

Drawings

Fig. 1 is a schematic diagram of the circuit structure of the present invention.

Fig. 2 is a schematic sampling diagram of an NTC probe of the present invention.

Fig. 3 is a schematic diagram of a sample shaping circuit of the present invention.

Fig. 4 is a partial schematic diagram of a sample and hold circuit of the present invention.

FIG. 5 is a graph of ADC value versus temperature according to the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.

Example (b):

the embodiment is a temperature calibration device of a DSFP optical module for 5G communication.

As shown in the structure of fig. 1, the temperature calibration device mainly comprises the following firmware: a microprocessor STM32G473 (hereinafter referred to as STM32G 473), USB/UART interface circuit, 4 DSFP sockets, temperature probe array (4 x2 NTC probes) and acquisition shaping circuit. STM32G473 passes through USB/UART interface circuit and is connected with the host computer, and the NTC probe of temperature probe array corresponds and locates DSFP socket department, and after DSFP inserted the DSFP socket, the DSFP was connected STM32G473, and two NTC probes passed through the probe briquetting and are pressed on the DSFP optical module simultaneously. For example, in one specific embodiment, as shown in fig. 2, two NTC probes are pressed against the laser (as indicated by the arrows) and the critical operating chip (e.g., DRIVER or DSP) in the corresponding optical module, respectively. The corresponding NTC probes on the four DSFPs form a temperature probe array, namely a 4 x2 NTC probe array.

The working principle is as follows:

the traditional NTC temperature sensor realizes temperature test, the essence of which is that the temperature test is realized by the change of the resistance value of the thermistor with negative temperature coefficient, and the empirical formula of the resistance value and the temperature change is as follows:

RT = RN expB(1/T–1/TN)

wherein RT is the resistance value of the NTC at the temperature T (K temperature);

RN: resistance value at rated temperature TN (K's temperature);

t: specifying a temperature value;

b: the material constant of the NTC thermistor is also called thermal sensitivity index;

exp: an index based on the natural number e (e = 2.71828 …).

In general, the nominal temperatures TN, B, RN are all provided by the NTC manufacturer. According to the voltage dividing value of the sampling resistor of the sampling shaping circuit of the microprocessor, the voltage dividing value is converted into a resistance value, and the specific value of the current temperature can be obtained according to the formula.

When monitoring the temperature of the DSFP optical module, a general user requires that the temperature monitoring of the DSFP optical module refers to the shell temperature of the DSFP optical module, and a test point is the position of a maximum power consumption component in the DSFP optical module. However, due to the influence of the distribution and structure of each device of the DSFP optical module, the position of the component with the largest power consumption may be different, and in order to ensure the accuracy of temperature calibration to the maximum, the embodiment adopts the method shown in fig. 2, two NTC probes are arranged at positions on the DSFP optical module, 2 NTC probes are arranged at a socket of the DSFP optical module to be measured, and after the DSFP optical module is inserted into the DSFP socket, the NTC probes are pressed into the DSP optical module. As shown in fig. 2, a dot indicated by a blue arrow symbol is a laser part of the DSFP optical module, and another dot is a part of a critical operating chip of the DSFP optical module, such as a DSP or DRIVER.

The NTC probe collects the temperature of the DSFP optical module and sends an analog signal to the STM32G473 through the sampling shaping circuit. The sampling and shaping circuit is shown in fig. 3, and comprises a sampling and holding circuit, a filter circuit and a voltage conditioning circuit which are connected in sequence, and the analog signal of the NTC probe is sent to an ADC port of the microprocessor through the sampling and holding circuit, the filter circuit and the voltage conditioning circuit in sequence. Meanwhile, in order to improve the sampling precision of the analog signal, a plurality of precise resistors with different resistance values can be arranged in parallel between the NTC probe and the sampling and holding circuit, a change-over switch is arranged between each precise resistor and the NTC probe, and STM32G473 selects different precise resistors to be connected into the sampling and holding circuit according to the temperature so as to ensure the sampling precision of each temperature section and the ADC sampling precision of the whole temperature range.

The working principle of each circuit structure in the sampling shaping circuit is as follows:

a sample-and-hold circuit: in the AD conversion of the analog signal, a certain conversion time is required, and the conversion accuracy can be ensured only if the analog signal is kept unchanged during the conversion time, so the sample-and-hold circuit is adopted in the present embodiment, and a high-precision resistor is arranged between the NTC probe and the sample-and-hold circuit, and a partial schematic diagram of the sample-and-hold circuit is shown in fig. 4. In the practical use process, the working temperature of the DSFP optical module can be industrial grade (-40-80 ℃) or commercial grade (0-70 ℃), the resistance change of the NTC in the whole temperature range can be changed from hundreds of ohms to hundreds of K ohms, namely the resistance value of the NTC is hundreds of K ohms at low temperature, at the moment, the precision resistor is 10K, the resistance value of the NTC at a normal temperature point is tens of K ohms, so the precision resistor is 4.7K ohms, and the voltage of the NTC is hundreds of ohms at high temperature, so the precision resistor is 1K ohm. Sampling precision resistors of different temperature points are different, 3 precision resistors are adopted in the calibration device, the STM32G473 of the calibration device controls the selector switch according to the temperature to select different precision resistors to be connected into the sampling and holding circuit, and therefore the accuracy of each temperature section is guaranteed, and meanwhile the ADC sampling precision of the whole temperature range is guaranteed.

A filter circuit: since the operating temperature range of the DSFP optical module is industrial grade and commercial grade, the temperature range is large, various interference sources such as power frequency interference of a temperature cycle box, DC/DC high frequency interference of a power supply of a calibration device and the like are inevitably introduced in the temperature cycle box by sampling of the NTC probe, and the ADC which is sampled is expected to be a direct current signal, a low-pass filter is necessary, for example, in one possible embodiment, an active low-pass filter built by a simple operational amplifier can be adopted.

The voltage conditioning circuit: because we's high accuracy reference source is 5V, but the reference source of STM32G473 on the calibrating device is 2.5V so the ADC sampling range is 2.5V, just so there is the voltage range of sampling to have the value that exceeds the scope, so need voltage conditioning circuit to input signal conditioning in order to satisfy the input voltage requirement, in addition except the voltage range of microprocessor STM32G473 in the conditioning input calibrating device, conditioning circuit can keep apart the signal and reduce the effect of disturbing in order to protect the ADC mouth of STM32G 473.

The workflow of this embodiment is as follows:

(1) temperature cycle is very important in the production process of the DSFP optical module, and the DSFP optical module is subjected to the change from-40 ℃ to 80 ℃ in the production process.

(2) The calibration device can calibrate 4 DSFP optical modules at a time, 4 DSFP optical modules are inserted into 4 DSFP sockets of the calibration device, and 2 spring NTC probes beside each DSFP socket are pressed on the positions of circular points in FIG. 2;

(3) and placing the calibration device in a temperature cycle box, and starting temperature cycle, wherein the temperature cycle range is-40-80 ℃.

(4) The upper computer controls temperature to circulate three temperature control points, namely, the low temperature is-40 ℃, the normal temperature is 25 ℃ and the high temperature is 80 ℃. The cooling rate is 1 ℃/min, and the heating rate is 5 ℃/min. STM32G473 started ADC sampling of each NTC probe in the NTC array 5 minutes after the temperature reached the three temperature control points when the temperature stabilized.

(5) After receiving an ADC sampling start command sent by the upper computer through the interface circuit, the STM32G473 of the calibration apparatus starts to sample the NTC probe arrays of the 4 sets of DSFP optical modules in sequence, and records the sampling commands as: two groups of temperature probes of the first DSFP are sampled 16 times respectively and are subjected to arithmetic filtering to obtain ADC1_1 and ADC1_2, two groups of temperature probes of the second DSFP are sampled 16 times respectively and are subjected to arithmetic filtering to obtain ADC2_1 and ADC2_2, two groups of temperature probes of the third DSFP are sampled 16 times respectively and are subjected to arithmetic filtering to obtain ADC3_1 and ADC3_2, and two groups of temperature probes of the fourth DSFP are sampled 16 times respectively and are subjected to arithmetic filtering to obtain ADC4_1 and ADC4_ 2.

(6) The memory of STM32G473 of the calibration apparatus holds a look-up table of sampled ADC values for 8 NTC probes, 4 x2 in total. The lookup table is generated into 3 lookup tables according to typical value design (temperature resistance corresponding table R-T curve) provided by each NTC manufacturer and different resistance values of precise resistors in the sampling protection circuit, and ADC sampling values of 1 ℃ are stored in the lookup tables from-40 ℃ to 100 ℃. And (4) selecting different lookup tables according to the precision resistance of the sampling and holding circuit selected by the STM32G473, and obtaining the corresponding temperature value of each group of NTC probes according to the ADC value obtained in the step (5) according to the corresponding lookup tables.

(7) Interpolation processing: during data acquisition of the ADC, each ADC data cannot be on an ADC value corresponding to an integer temperature point, so that the ADC data is generally accurately positioned if the two data are in the middle. And obtaining the final NTC accurate temperature value by interpolation calculation, as shown in FIG. 5.

In fig. 5, the X-axis is temperature and the Y-axis is ADC value. Knowing the point (X1, Y1) and the point (X2, Y2), the agenda for finding the actual (Xi, Yi) from the two points to obtain the straight line L is as follows:

since the point (X1, Y1) and the point (X2, Y2) are two adjacent temperature points, X2-X1=1, the following formula is obtained:

therefore, the real temperature value of each NTC probe of each DSFP optical module can be calculated.

(8) The reporting temperature of the DSFP optical module generally requires that the temperature refers to the shell temperature of the optical module, and a test point is a component with the largest power consumption in the module. The internal temperature and heat distribution of the DSFP optical module are different, and the high-power heating device comprises a laser, a Digital Signal Processor (DSP), a laser driving chip and the like, so that two NTC probes are adopted for accurate sampling in the embodiment. The STM32G473 averages the temperature values obtained by the two NTC probes of each group of DSFP optical modules, and the value is used as a real calibration temperature value reported by the DSFP optical module. The STM32G473 reports the true calibration temperature value to the host computer.

(9) And the upper computer compares the difference value of the real calibration temperature value of the DSFP optical module with the temperature value read by the temperature sensor in the DSFP optical module in the full temperature range, performs linear fitting in the full temperature range in a segmented manner to obtain a temperature difference value lookup table of the DSFP optical module, and writes the temperature difference value lookup table into a storage of the DSFP optical module through an STM32G473 and an I2C bus of the DSFP optical module, so that the temperature calibration of the DSFP optical module is completed. And (4) performing the same treatment on the 4 DSFP optical modules to finish the temperature calibration of the 4 DSFP optical modules.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.

Claims

1. A temperature calibrating device for 5G communication optical module characterized in that: the temperature probe array is composed of at least two temperature probes arranged on each optical module, and the temperature probes are connected with the microprocessor through the sampling shaping circuit.

2. The temperature calibration device for the 5G communication optical module according to claim 1, wherein: the sampling shaping circuit comprises a sampling holding circuit, a filter circuit and a voltage conditioning circuit which are connected in sequence, and analog signals collected by the temperature probe are sent to an ADC port of the microprocessor through the sampling holding circuit, the filter circuit and the voltage conditioning circuit in sequence.

3. The temperature calibration device for the 5G communication optical module according to claim 2, wherein: the sampling shaping circuit also comprises a plurality of precision resistors with different resistance values, which are connected in parallel between the temperature probe and the sampling holding circuit, and a change-over switch controlled by a microprocessor is arranged between each precision resistor and the temperature probe.

4. The temperature calibration device for the 5G communication optical module according to claim 1, wherein: and two temperature probes are arranged on each optical module and are respectively and correspondingly arranged at the positions of the laser and the working chip in the optical module.

5. The temperature calibration device for the 5G communication optical module according to claim 4, wherein: the working chip is a driver or a digital signal processor.

6. The temperature calibration device for the 5G communication optical module according to claim 4, wherein: the number of the optical module sockets is four, and the temperature probe array is composed of 4 multiplied by 2 temperature probes.

7. The temperature calibration device for 5G communication optical module according to claim 1, wherein: the temperature probe is an NTC probe.