Measurement system of TEC device and method for measuring ACR

Abstract

The invention provides a measurement system of a TEC device and a method for measuring ACR, the measurement system comprises a current detection circuit and a driving circuit, the driving circuit comprises a micro-control unit and a TEC controller, the TEC controller generates an excitation voltage pulse based on a driving signal, the voltage under a first pulse of the excitation voltage pulse is a forward voltage, and the voltage under a second pulse of the excitation voltage pulse is a reverse voltage. The voltage under the second pulse is negative voltage; the current detection circuit generates a first sampling signal based on the first pulse and generates a second sampling signal based on the second pulse; the micro-control unit obtains a first working current according to the first sampling signal, obtains a second working current according to the second sampling signal, and obtains the AC resistance of the TEC device based on the positive voltage, the negative voltage, the first working current and the second working current. According to the invention, an LCR tester is not needed, and AC resistance measurement is completed by multiplexing an existing drive circuit and combining excitation voltage pulse and DC check calculation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical modules, and particularly relates to a TEC device measurement system and a method for measuring ACR. BACKGROUND

[0002] TEC devices (also known as thermoelectric coolers or semiconductor coolers) are usually used to control the temperature of precision electronic components or samples due to their small size and ease of use, and are widely used in fields such as optical communication modules, laser radars, medical devices, precision instruments, etc.

[0003] ACR (Alternating Current Resistance) is a key parameter of a TEC device, which mainly represents the impedance characteristics of the stacked PN junction of the TEC device under alternating current, and reflects the PN process defects or aging characteristics of the TEC device. It is crucial for the process and reliability of products. Products configured with TEC devices usually perform ACR tests on TEC devices before assembly to ensure product quality. If a product is configured with a TEC device, ACR testing of the TEC device is also included in the failure detection of the product, and the aging degree of the TEC device can be determined in combination with the ACR test value at the early stage of the product life.

[0004] The current mainstream test scheme is to use a "bench LCR combined with a probe / jig" peripheral, which has inherent defects that are increasingly prominent: a specific test post needs to be built, the test equipment needs to be customized with a probe and a test jig, and the LCR instrument host is not small, which is not simple to arrange with the previous and subsequent processes; probe life, contact pressure and oxidation bring about repeatability drift, which also requires frequent manual calibration and maintenance; the equipment cost is high, and the single measurement time is not short enough.

[0005] Therefore, in view of the above technical problems, it is necessary to provide a TEC device measurement system and a method for measuring ACR. SUMMARY

[0006] The purpose of the present application is to provide a TEC device measurement system and a method for measuring ACR, which can measure the alternating current resistance of the TEC device by multiplexing the existing drive circuit and combining AC excitation-DC calculation without an LCR tester.

[0007] In order to achieve the above-mentioned purpose, the technical scheme provided by an embodiment of the present application is as follows:

[0008] A TEC device measurement system, comprising a drive circuit for driving a TEC device, the drive circuit comprising a micro control unit and a TEC controller, the measurement system further comprising a current detection circuit;

[0009] The micro control unit is configured to generate a driving signal, and the TEC controller is configured to generate an excitation voltage pulse based on the driving signal, the excitation voltage pulse comprising a plurality of periodically alternating first pulses and second pulses, a voltage in the first pulse being a positive voltage , and a voltage in the second pulse being a negative voltage .

[0010] The current detection circuit is configured to generate a first sampling signal based on the first pulse and a second sampling signal based on the second pulse;

[0011] The micro control unit is configured to obtain a first working current based on the first sampling signal, a second working current based on the second sampling signal, and an AC resistance of the TEC device based on the positive voltage , the negative voltage , the first working current , and the second working current . .

[0012] In one or more embodiments of the present application, the current detection circuit comprises a sampling resistor, a filter unit, and an amplifier unit;

[0013] A first end of the sampling resistor is connected to a first end of the TEC device, and a second end of the sampling resistor is connected to a second end of the TEC device, the filter unit is connected between the sampling resistor and the amplifier unit, and is configured to filter out noise, a first input end and a second input end of the amplifier unit are connected to the filter unit, and an output end of the amplifier unit is directly or indirectly connected to the micro control unit.

[0014] In one or more embodiments of the present application, the driving circuit further comprises a digital-to-analog converter, the digital-to-analog converter being connected between the micro control unit and the TEC controller, and being configured to perform digital-to-analog conversion on the driving signal;

[0015] The driving circuit further comprises an analog-to-digital converter, a first end of the analog-to-digital converter being connected to an output end of the TEC controller and the current detection circuit, and a second end of the analog-to-digital converter being connected to the micro control unit, and the analog-to-digital converter being configured to perform analog-to-digital conversion on the first sampling signal, the first sampling signal, the positive voltage , and / or the negative voltage .

[0016] ​In one or more embodiments of the present invention, the TEC device is used to adjust the temperature of the temperature-controlled device, and the driving circuit further includes a temperature detection unit. The temperature detection unit is used to sample the temperature of the temperature-controlled device and acquire a temperature sampling signal. The microcontroller unit is used to determine, based on the temperature sampling signal, whether the temperature change of the temperature-controlled device at several sampling times is less than or equal to a set threshold. If so, the resistance measurement process is started; otherwise, the temperature sampling signal is acquired.

[0017] In one or more embodiments of the present invention, the measurement system further includes a filtering circuit, the input terminal of which is connected to the output terminal of the TEC controller to receive the excitation voltage pulse, and the output terminal is directly or indirectly connected to the microcontroller unit for filtering out the positive voltage. and / or negative voltage ripples.

[0018] Another aspect of the present invention provides a method for measuring ACR, the method comprising:

[0019] The TEC controller generates an excitation voltage pulse based on a drive signal and applies the excitation voltage pulse to both ends of the TEC device. The excitation voltage pulse includes multiple periodically alternating first pulses and second pulses, with the voltage under the first pulse being a positive voltage. The voltage under the second pulse is a negative voltage. ;

[0020] A first sampling signal is generated based on a first pulse by a current detection circuit, and a second sampling signal is generated based on a second pulse.

[0021] The microcontroller obtains the first operating current based on the first sampling signal. The second operating current is obtained based on the second sampling signal. ;

[0022] Based on forward voltage negative voltage First operating current Second operating current Obtain the AC resistance of TEC devices ,in, .

[0023] In one or more embodiments of the present invention, the method for measuring ACR further includes:

[0024] The temperature of the temperature-controlled device is sampled by the temperature detection unit, and the temperature sampling signal is obtained.

[0025] The micro control unit judges whether the temperature change of the temperature controlled device at several sampling time points is less than or equal to a set threshold value based on the temperature sampling signal, if yes, the resistance measurement process is started, if not, the temperature sampling signal is continuously acquired.

[0026] In one or more embodiments of the present application, the method for measuring ACR further comprises: turning off the TEC controller, acquiring a zero current bias voltage Vos_current of the current detection circuit, and calibrating the first sampling signal and / or the second sampling signal based on the zero current bias voltage Vos_current;

[0027] The method further comprises: turning on the TEC controller, generating an actual excitation voltage pulse based on an initial driving signal by the TEC controller, acquiring a gain of the TEC controller based on the initial driving signal and the actual excitation voltage pulse, acquiring an offset error of the TEC controller based on an error between the actual excitation voltage pulse and a target excitation voltage pulse, and acquiring a target driving signal corresponding to the target excitation voltage pulse based on the gain and the offset error.

[0028] In one or more embodiments of the present application, the method for measuring ACR further comprises:

[0029] After the TEC controller generates the excitation voltage pulse based on the driving signal, a stable interval of the excitation voltage pulse is acquired, the excitation voltage pulse frequency in the stable interval is equal, and the amplitude of all positive voltages in the stable interval is equal, and the amplitude of all negative voltages in the stable interval is equal;

[0030] A last group of adjacent and sequentially arranged first pulses and second pulses in the stable interval are selected, and the positive voltage , the negative voltage , the first working current and the second working current corresponding to the selected first pulse and second pulse are used to acquire the alternating current resistance of the TEC device.

[0031] In one or more embodiments of the present application, the positive voltage is equal to the negative voltage , and the pulse width of the excitation voltage pulse under the first pulse is equal to the pulse width under the second pulse.

[0032] The positive voltage is 100-200mV, and the negative voltage is -100--200mV.

[0033] The frequency of the excitation voltage pulse is 10-500Hz.

[0034] Compared with the prior art, the measurement system of the TEC device and the method for measuring ACR of the present application avoid the continuous change of the temperature at both ends of the TEC device by exciting the TEC device with a voltage excitation pulse and performing a thermoelectric current offset calculation on the bidirectional current, while enhancing the current detection accuracy and obtaining high-precision alternating resistance. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments described in the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0036] Figure 1 The figure is a principle block diagram of the measurement system of the TEC device in an embodiment of the present application.

[0037] Figure 2 The figure is a circuit diagram of the current detection circuit in an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the person skilled in the art better understand the technical solutions in the present disclosure, the technical solutions in the embodiments of the present disclosure will be described clearly and completely below in combination with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only some of the embodiments of the present disclosure, not all. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present disclosure.

[0039] In the prior art, the ACR test of the TEC device built-in in the TOSA (transmit optical subassembly) / ROSA (receive optical subassembly) and other devices adopts a four-wire test device built with a high-precision LCR instrument and a clamp such as a probe. The disadvantage is that the cost of the high-precision LCR instrument and the probe is very high, and the mechanical life of the probe is limited. The contact resistance will produce oxidation / wear drift, and needs to be frequently checked. In addition, during the test process, the devices configured with TEC such as OSA (transmit optical subassembly) / ROSA (receive optical subassembly) need to be taken out and placed in the test equipment, which not only greatly increases the single measurement time, but also increases the risk factors such as ESD.

[0040] Another existing TEC device testing scheme is constant current voltage measurement method: using DC constant current step signal combined with voltage sampling to calculate the DC resistance (Rdc) of TEC device, and the DC resistance represents the PN process defects or aging degree of thermoelectric cooler. The disadvantage is that the test time is often limited by the system heat capacity, and the test needs to be completed before the heat is established, which requires high test instruments; the test accuracy of microcracks, interface delamination and other defects is lower than that of ACR test.

[0041] To solve the above technical problems, the present disclosure provides a TEC device measurement system and a corresponding method for measuring ACR, which realizes accurate measurement of the AC resistance of TEC device. The present disclosure can directly use the existing TEC driving board, without removing the TEC device or placing the assembly with the TEC device in the test system, and meets the demand for performance evaluation of TEC and products in the online manufacturing link of TEC device products.

[0042] Reference Figure 1 As shown in the figure, the TEC device measurement system in the present disclosure includes a current detection circuit 21 and a driving circuit for driving the TEC device 10, wherein the driving circuit includes a micro control unit 11 and a TEC controller 12.

[0043] The micro control unit 11 (MCU) is used to generate a driving signal, and the TEC controller 12 is used to generate an excitation voltage pulse based on the driving signal, the excitation voltage pulse including a plurality of periodically alternating first pulses and second pulses, the voltage under the first pulse being a positive voltage , and the voltage under the second pulse being a negative voltage .

[0044] The current detection circuit 21 is used to generate a first sampling signal Vout1 based on the voltage difference across the TEC device 10 under the first pulse, and a second sampling signal Vout2 based on the voltage difference across the TEC device 10 under the second pulse;

[0045] The micro control unit 11 is used to obtain a first working current according to the first sampling signal Vout1, a second working current according to the second sampling signal Vout2, and an AC resistance of the TEC device 10 based on the positive voltage , the negative voltage , the first working current and the second working current , wherein, .

[0046] It can be understood that for the TEC controller 12 integrated with the power stage, the output current can be roughly measured by the direct current resistance of the internal MOSFET. The present disclosure detects the working current of the TEC device 10 with high sensitivity by setting a separate current detection circuit 21 in the measurement system, and the resolution is better than 0.1 mA.

[0047] The present disclosure also proposes a high-precision estimation method for measuring alternating current resistance ACR, which uses excitation voltage pulse to bidirectionally excite both ends of the TEC device 10, avoids the TEC device 10 from generating cumulative temperature difference during testing, and improves the accuracy of the results; by respectively collecting the working current under the positive and negative period voltages, and offsetting the current generated by the TEC device 10 The influence of the temperature difference on the performance of the TEC device 10 is eliminated, and the stable direct current resistance DCR close to the alternating current resistance is obtained. .

[0048] In combination Figure 2 As shown in FIG. 1, the current detection circuit 21 in an embodiment includes a sampling resistor Rse, a filter unit, and an amplifier unit.

[0049] The first end of the sampling resistor Rse is connected to the first end P1 of the TEC device 10, and the second end is connected to the second end P2 of the TEC device 10.

[0050] The filter unit in an embodiment is an RC low-pass filter for filtering out high-frequency noise. The filter unit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first capacitor C1. The first end of the first resistor R1 is connected to the first end of the sampling resistor Rse, and the second end is connected to the first end of the second resistor R2 and the first end of the first capacitor C1. The first end of the third resistor R3 is connected to the second end of the sampling resistor Rse, and the second end is connected to the first end of the fourth resistor R4 and the second end of the first capacitor C1. The second end of the second resistor R2 is connected to the first input end of the amplifier Amp, and the second end of the fourth resistor R4 is connected to the second input end of the amplifier Amp.

[0051] The amplifier unit includes an amplifier Amp, an input resistor Rin, and a feedback resistor Rfb. The input resistor Rin is connected between the reference voltage Vref and the first input end of the amplifier Amp. The feedback resistor Rfb is connected between the second input end of the amplifier Amp and the output end of the amplifier Amp. The output end of the amplifier Amp is used to output the first sampling signal Vout1 and the second sampling signal Vout2.

[0052] ​Based on the working principle of the current detection circuit 21, under the first pulse, the amplifier unit generates the first sampling signal Vout1 based on the voltage difference across the sampling resistor Rse, and under the second pulse, the amplifier unit generates the second sampling signal Vout2 based on the voltage difference across the sampling resistor Rse. After the micro-processing unit processes the first sampling signal Vout1 and the second sampling signal Vout2, the corresponding first working current and the second working current Therefore, although the first sampling signal Vout1 and the second sampling signal Vout2 are both voltage signals, they can represent the change of the current.

[0053] It can be understood that the working principle of the amplifier unit and the sampling resistor Rse is well known in the prior art, and therefore will not be described in detail here. Any known or unknown current detection circuit 21 can be used without limitation.

[0054] Further, the driving circuit in an embodiment further comprises a digital-to-analog converter 13 and an analog-to-digital converter 14.

[0055] The digital-to-analog converter 13 is connected between the micro-control unit 11 and the TEC controller 12, and is used to perform digital-to-analog conversion on the driving signal to obtain the corresponding driving voltage Vin. It can be understood that the driving signal generated by the micro-control unit 11 is a Code value, which is a digital signal and cannot directly drive the TEC driver. Therefore, the driving signal needs to be converted into a corresponding analog signal (i.e. the driving voltage Vin) by the digital-to-analog converter 13. Therefore, the essence of the driving signal and the driving voltage Vin is the same.

[0056] The first end of the analog-to-digital converter 14 is connected to the first output end of the TEC controller 12 and the current detection circuit 21, and the second end is connected to the micro-control unit 11, and is used to perform analog-to-digital conversion on the first sampling signal Vout1, the first sampling signal Vout1, the forward voltage and the negative voltage to obtain signals that can be processed by the micro-control unit 11.

[0057] It can be understood that the working principle of the digital-to-analog converter 13 and the analog-to-digital converter 14 is well known in the prior art, and therefore will not be described in detail here. Any known or unknown digital-to-analog converter and analog-to-digital converter can be used without limitation.

[0058] The TEC device 10 transports heat based on the Peltier effect to regulate the temperature of the temperature-controlled device. The driving circuit in an embodiment further comprises a temperature detection unit configured to sample the temperature of the temperature-controlled device 15 and obtain a temperature sampling signal. The micro control unit 11 is configured to determine whether the temperature change of the temperature-controlled device 15 at a plurality of sampling time instants is less than or equal to a set threshold based on the temperature sampling signal. If yes, the resistance measurement process is started. If no, the temperature sampling signal is continuously obtained.

[0059] Optionally, the temperature detection unit 16 comprises a thermistor RTH.

[0060] The TEC controller 12 in an embodiment integrates a power stage, wherein the power stage comprises a Buck step-down converter and a LDO linear voltage regulator. The power stage is configured to supply power to the TEC device 10 and to maximize the voltage difference across the TEC device 10 to 3V.

[0061] Exemplarily, the TEC controller 12 comprises an MP8833 series TEC controller or an ADN8834 series TEC controller.

[0062] The measurement system in an embodiment further comprises a filter circuit 22, wherein the input of the filter circuit 22 is connected to the output of the TEC controller 12 to receive the excitation voltage pulses, and the output of the filter circuit 22 is indirectly connected to the micro control unit 11 to filter out the ripple of the forward voltage and the backward voltage Exemplarily, the filter circuit 22 is an RC low-pass filter circuit 22.

[0063] It can be understood that the first output and the second output of the TEC controller 12 are respectively connected to the two ends of the TEC device 10, and the filter circuit 22 is also connected to the two ends of the TEC device 10.

[0064] Further, the analog-to-digital converter 14 in an embodiment is configured with a programmable gain amplifier (PGA) to realize gain adjustment based on digital control to adapt to different amplitudes of the first sampling signal Vout1, the second sampling signal Vout2, the forward voltage and the backward voltage The programmable gain amplifier (PGA) realizes far-end differential acquisition of the forward voltage and the backward voltage in combination with the RC low-pass filter circuit.

[0065] The internal resistance of the TEC device 10 is usually small, for example, the internal resistance of the TEC device 10 used in a small optical module is usually about 1.2 ohms. The present disclosure compensates for the line voltage drop by remote differential acquisition for accurate measurement of the voltage on both sides of the TEC device 10. Furthermore, one side of the power stage in the TEC controller 12 is a linear voltage regulation circuit and the other side is a switching voltage reduction circuit, wherein the switching voltage reduction circuit generates ripple, and the present disclosure filters out the voltage ripple by setting the filter circuit 22.

[0066] It can be understood that the existing TEC drive board 100 is usually integrated with a micro control unit 11, a TEC controller 12, a temperature detection unit 16, a digital-to-analog converter 13 and an analog-to-digital converter 14, and the TEC device 10 to be driven is also integrated on the TEC drive board 100. The present disclosure integrates the current detection circuit 21 and the filter circuit 22 on the existing TEC drive board 100, quickly evaluates the ACR index of the TEC device 10, is suitable for online testing of any product with a built-in TEC device, and can trace the performance of the TEC device 10 throughout the life cycle.

[0067] In addition, the present disclosure can integrate the micro control unit 11, the TEC controller 12, the temperature detection unit 16, the current detection circuit 21, the filter circuit 22, the digital-to-analog converter 13 and the analog-to-digital converter 14 and prepare them as an external test instrument to replace the existing test device (such as an LCR instrument) and simplify the TEC drive board 100.

[0068] Another aspect of the present disclosure provides a method for measuring ACR, which is realized based on the above-mentioned measurement system and is used for measuring the AC resistance of the TEC device 10, and specifically includes:

[0069] S101, generating an excitation voltage pulse based on a drive signal by the TEC controller 12 and applying the excitation voltage pulse to both ends of the TEC device 10, wherein the excitation voltage pulse includes a plurality of periodically alternating first pulses and second pulses, the voltage under the first pulse is a positive voltage , and the voltage under the second pulse is a negative voltage ;

[0070] S102, generating a first sampling signal Vout1 based on the voltage difference between both ends of the TEC device 10 by the current detection circuit 21 under the first pulse, and obtaining a first working current by the micro control unit 11 according to the first sampling signal Vout1;

[0071] S103, generating a second sampling signal Vout2 based on the voltage difference between both ends of the TEC device 10 by the current detection circuit 21 under the second pulse, and obtaining a second working current by the micro control unit 11 according to the second sampling signal Vout2;

[0072] S104, obtaining the forward voltage , the negative voltage , the first working current and the second working current obtaining the AC resistance of the TEC device 10 wherein, .

[0073] Further, the method for measuring the ACR in the embodiment further comprises initializing the measurement system, specifically:

[0074] Before the test, the TEC controller 12 is turned off, the digital-to-analog conversion unit 13 and the analog-to-digital conversion unit 14 are initialized;

[0075] The temperature of the temperature-controlled device 15 is sampled by the temperature detection unit 16 and a temperature sampling signal is obtained;

[0076] The micro-control unit 11 judges whether the temperature change of the temperature-controlled device at a plurality of sampling times is less than or equal to a set threshold value based on the temperature sampling signal, if yes, the resistance measurement process is started, if not, the temperature sampling signal is continuously obtained.

[0077] It can be understood that the TEC device 10 transports heat based on the Peltier effect to adjust the temperature of the temperature-controlled device 15, that is, whether the temperature of the temperature-controlled device 15 is stable, which reflects whether the state of the TEC device 10 is stable. Therefore, before the formal test, the disclosure first judges whether the temperature of the temperature-controlled device 15 is stable by sampling, ensures that the TEC device 10 is in a stable state to improve the test precision, and at the same time avoids the influence of temperature change on the test accuracy.

[0078] Further, the disclosure also calibrates the TEC controller 12 and the current detection circuit 21 before the test, specifically including:

[0079] S201, turning off the TEC controller 12, obtaining the zero-current bias voltage Vos_current of the current detection circuit 21, and calibrating the first sampling signal Vout1 and the second sampling signal Vout2 based on the zero-current bias voltage Vos_current.

[0080] S202, turning on the TEC controller 12, generating an actual excitation voltage pulse based on the initial driving signal by the TEC controller 12, obtaining the gain Gain of the TEC controller 12 based on the initial driving signal and the actual excitation voltage pulse, obtaining the offset error Offset of the TEC controller 12 based on the error between the actual excitation voltage pulse and the target excitation voltage pulse, and obtaining the target driving signal corresponding to the target excitation voltage pulse based on the gain Gain and the offset error Offset.

[0081] The gain of the TEC controller 12 is obtained based on the initial driving signal and the actual excitation voltage pulse, and the offset error of the TEC controller 12 is obtained based on the error between the actual excitation voltage pulse and the target excitation voltage pulse.

[0082] Exemplarily, the TEC controller 12 has a preset gain (but it is not determined whether the preset gain is accurate), and the micro control unit 11 generates the initial driving signal based on the preset gain and the target excitation voltage pulse (for example, the target excitation voltage pulse is a pulse voltage of 100 mV around the reference zero point voltage, and the pulse width ratio is 1:1);

[0083] The initial driving signal is applied to the TEC controller 12, the actual excitation voltage pulse generated by the TEC controller 12 is obtained through the analog-to-digital conversion unit 14, and the offset error Offset of the TEC controller 12 is obtained based on the error between the actual excitation voltage pulse and the target excitation voltage pulse;

[0084] Based on the gain Gain and the offset error Offset, the target driving signal output by the micro control unit 11 when the TEC controller 12 is expected to output the target excitation voltage pulse is calculated reversely.

[0085] The method for measuring the ACR in an embodiment further comprises:

[0086] After the TEC controller 12 generates the excitation voltage pulse based on the driving signal, the excitation voltage pulse period occurs, and after a plurality of periods are continuously generated, a stable interval of the excitation voltage pulse is obtained (generally after 7-8 periods of starting generation), the excitation voltage pulse frequency in the stable interval is equal, and the amplitudes of all positive voltages in the stable interval are equal, and the amplitudes of all negative voltages in the stable interval are equal; the stable interval is substantially a period interval; the excitation voltage pulse includes a first pulse and a second pulse, which periodically and alternately appear;

[0087] Optionally, the first pulse has a first period, and the second pulse has a second period, and preferably, the ratio of the first period to the second period is 1:1.

[0088] A last group of adjacent and sequentially arranged first pulses and second pulses in the stable interval are selected, and the positive voltage , the negative voltage , the first working current , and the second working current corresponding to the selected first pulse and the second pulse are obtained to obtain the alternating resistance of the TEC device 10.

[0089] Exemplarily, the excitation voltage pulse includes 10 first pulses and 10 second pulses, which can also be understood as that the excitation voltage pulse contains 10 cycle lengths, wherein the stable interval of the excitation voltage pulse is the fifth first pulse~the tenth second pulse, and the positive voltage corresponding to the tenth first pulse is taken as the positive voltage V+ of the excitation voltage pulse and the negative voltage corresponding to the tenth second pulse is taken as the negative voltage V- of the excitation voltage pulse The AC resistance of the TEC device 10 is obtained .

[0090] Further, in an embodiment, the positive voltage V+ is equal to the negative voltage V-, and the pulse width of the excitation voltage pulse under the first pulse is equal to the pulse width under the second pulse. The positive voltage V+ is equal to the negative voltage V-.

[0091] The positive voltage V+ is 100~200 mV, and the negative voltage V- is -100~-200 mV.

[0092] The frequency of the excitation voltage pulse is 10~500 Hz.

[0093] It can be understood that the inside of the TEC device 10 is a series-parallel array composed of a large number of PN junction semiconductor particles, which is packaged between the upper and lower ceramic substrates. When there is a temperature difference between the upper and lower ceramic surfaces of the TEC device 10, heat will flow through each PN junction. Under the action of the Seebeck effect, each independent PN junction will generate a small induced potential. Through the internal series design, all the small induced potentials are added up, and finally a measurable Seebeck voltage is output at the electrode lead end of the TEC. If the cold-hot end temperature difference is ΔT and the Seebeck coefficient is S, then the Seebeck voltage is .

[0094] The Seebeck voltage will be superimposed on the excitation voltage pulse generated by the TEC controller 12, resulting in that the actual current contains a static bias current Iseebeck, which deviates from the calculated value of the pure Ohm's law.

[0095] Assuming that there is a certain temperature difference between the two sides of the TEC device 10, a unidirectional Seebeck voltage is formed, under the first pulse, the actual current applied to the PN junction (i.e., the first working current ) , DCR represents the DC resistance of the TEC device 10, and under the second pulse, the actual current applied to the PN junction (i.e., the second working current ) , then .

[0096] ​​​Because of the existence of positive and negative voltage excitation, and the actual working current under the first pulse and the second pulse is obtained respectively, the current caused by external temperature difference is unidirectional, the influence of static bias current Iseebeck is eliminated by operation, and therefore the alternating current resistance ACR is approximately equal to the direct current resistance DCR.

[0097] The present disclosure designs a contrast test to verify the measurement system and the method for measuring ACR: the alternating current resistance of the small optical module TEC device 10 is obtained by the present disclosure and the LCR bridge test respectively, and the test results are all about 1.13~1.14 ohms, reaching 10 milliohm accuracy.

[0098] The present disclosure uses low-frequency alternating small-amplitude excitation voltage pulse to excite the TEC device, avoids the continuous change of the temperature at both ends of the TEC device, enhances the current detection accuracy, and performs temperature difference current offset calculation on the bidirectional current, so the measurement result is very close to the true ACR.

[0099] From the above technical solutions, the present application has the following beneficial effects:

[0100] It can be integrated on the existing TEC driving circuit board, without the need to build a test device, and without the need to take down the TEC device during the test process, and without the need to take and place the component configured with the TEC device in the test system, only through AC excitation-DC calculation, the test is completed in seconds, greatly saving the single measurement time;

[0101] The test precision is greatly improved through the current detection circuit and the filter circuit;

[0102] The performance of the TEC device can be traced throughout the life cycle: for example, by setting the ACR of the self-test on startup and recording it in the local system, forming an ACR use aging time curve data for analysis.

[0103] It is obvious for those skilled in the art that the present disclosure is not limited to the details of the above exemplary embodiments, and the present disclosure can be implemented in other specific forms without departing from the spirit or essential characteristics of the present disclosure. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present disclosure is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present disclosure. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0104] Furthermore, it should be understood that although the specification is described in terms of embodiments, not every embodiment includes every feature described. The specification can include implicit combinations of explicitly mentioned features and / or explicit combinations of implicitely mentioned features. Each embodiment depends on the explicit combinations of features and / or the implicit combinations of features made specifically within that embodiment, and each such embodiment can be combined with every other such embodiment to create further embodiments.

Claims

1. A measurement system for a TEC device, comprising a drive circuit for driving the TEC device, said drive circuit including a microcontroller unit and a TEC controller, characterized in that, The measurement system also includes a current detection circuit; The microcontroller unit is used to generate a drive signal, and the TEC controller is used to generate an excitation voltage pulse based on the drive signal. The excitation voltage pulse includes multiple periodically alternating first pulses and second pulses, and the voltage under the first pulse is a positive voltage. The voltage under the second pulse is a negative voltage. ; The current detection circuit is used to generate a first sampling signal based on a first pulse and a second sampling signal based on a second pulse. The microcontroller unit is used to obtain the first operating current based on the first sampling signal. The second operating current is obtained based on the second sampling signal. And based on positive voltage negative voltage First operating current Second operating current Obtain the AC resistance of TEC devices ,in, .

2. The measurement system for the TEC device according to claim 1, characterized in that, The current detection circuit includes a sampling resistor, a filtering unit, and an amplifier unit; The first end of the sampling resistor is connected to the first end of the TEC device, and the second end is connected to the second end of the TEC device. The filtering unit is connected between the sampling resistor and the amplifier unit to filter out noise. The first input end and the second input end of the amplifier unit are connected to the filtering unit, and the output end is directly or indirectly connected to the microcontroller unit.

3. The measurement system for the TEC device according to claim 1, characterized in that, The drive circuit further includes a digital-to-analog converter (DAC), which is connected between the microcontroller and the TEC controller, for performing digital-to-analog conversion on the drive signal; and / or, The driving circuit further includes an analog-to-digital converter. A first terminal of the analog-to-digital converter is connected to the output terminal of the TEC controller and the current detection circuit, and a second terminal is connected to the microcontroller unit. It is used to process the first sampling signal, the first sampling signal, and the positive voltage. and / or negative voltage Perform analog-to-digital conversion.

4. The measurement system for the TEC device according to claim 1, characterized in that, The TEC device is used to regulate the temperature of the controlled temperature device. The driving circuit also includes a temperature detection unit, which is used to sample the temperature of the controlled temperature device and acquire a temperature sampling signal. The microcontroller unit is used to determine, based on the temperature sampling signal, whether the temperature change of the controlled temperature device at several sampling times is less than or equal to a set threshold. If so, the resistance measurement process is started; otherwise, the temperature sampling signal is acquired.

5. The measurement system for the TEC device according to claim 1, characterized in that, The measurement system further includes a filtering circuit. The input terminal of the filtering circuit is connected to the output terminal of the TEC controller to receive the excitation voltage pulse, and the output terminal is directly or indirectly connected to the microcontroller unit to filter out the positive voltage. and / or negative voltage ripples.

6. A method for measuring ACR, characterized in that, The method includes: The TEC controller generates an excitation voltage pulse based on a drive signal and applies the excitation voltage pulse to both ends of the TEC device. The excitation voltage pulse includes multiple periodically alternating first pulses and second pulses, with the voltage under the first pulse being a positive voltage. The voltage under the second pulse is a negative voltage. ; A first sampling signal is generated based on a first pulse by a current detection circuit, and a second sampling signal is generated based on a second pulse. The microcontroller obtains the first operating current based on the first sampling signal. The second operating current is obtained based on the second sampling signal. ; Based on forward voltage negative voltage First operating current Second operating current Obtain the AC resistance of TEC devices ,in, .

7. The method for measuring ACR according to claim 6, characterized in that, The method further includes: The temperature of the temperature-controlled device is sampled by the temperature detection unit, and the temperature sampling signal is obtained. The microcontroller determines whether the temperature change of the controlled device at several sampling times is less than or equal to a set threshold based on the temperature sampling signal. If yes, the measurement process is started; otherwise, the temperature sampling signal is acquired again.

8. The method for measuring ACR according to claim 6, characterized in that, The method further includes: turning off the TEC controller, acquiring the zero-current bias voltage Vos_current of the current sensing circuit, and calibrating the first sampling signal and / or the second sampling signal based on the zero-current bias voltage Vos_current; and / or, The method further includes: activating the TEC controller, generating an actual excitation voltage pulse based on an initial drive signal through the TEC controller, obtaining the gain of the TEC controller based on the initial drive signal and the actual excitation voltage pulse, obtaining the offset error of the TEC controller based on the error between the actual excitation voltage pulse and the target excitation voltage pulse, and obtaining the target drive signal corresponding to the target excitation voltage pulse based on the gain and the offset error.

9. The method for measuring ACR according to claim 6, characterized in that, The method further includes: After the TEC controller generates an excitation voltage pulse based on the drive signal, the stable range of the excitation voltage pulse is obtained. The frequency of the excitation voltage pulse within the stable range is equal, and all positive voltages within the stable range are... The amplitudes are equal, and all negative voltages The amplitudes are equal; Select the last pair of adjacent and sequentially arranged first and second pulses within the stable interval, and use the positive voltage corresponding to the selected first and second pulses. negative voltage First operating current Second operating current Obtain the AC resistance of TEC devices .

10. The method for measuring ACR according to claim 6, characterized in that, The positive voltage With the negative voltage They are equal, and the pulse width of the first pulse is equal to the pulse width of the second pulse; And / or, The positive voltage 100~200mV, negative voltage -100 to -200 mV; and / or, The frequency of the excitation voltage pulse is 10~500Hz.

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