CN105807198B - A kind of device that diode is screened based on reverse recovery time - Google Patents
A kind of device that diode is screened based on reverse recovery time Download PDFInfo
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- CN105807198B CN105807198B CN201610149876.1A CN201610149876A CN105807198B CN 105807198 B CN105807198 B CN 105807198B CN 201610149876 A CN201610149876 A CN 201610149876A CN 105807198 B CN105807198 B CN 105807198B
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- 238000012360 testing method Methods 0.000 claims abstract description 45
- 238000001514 detection method Methods 0.000 claims abstract description 25
- 238000012216 screening Methods 0.000 claims abstract description 17
- 238000012545 processing Methods 0.000 claims abstract description 14
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/26—Testing of individual semiconductor devices
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- G01R31/2632—Circuits therefor for testing diodes
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Abstract
The present invention provides a kind of device that diode is screened based on reverse recovery time, including sequentially connected reverse recovery time test circuit, signal processing circuit, master controller and sorting circuit.When measured diode passes through the loading forward current pulse of reverse recovery time test circuit and reverse voltage pulse, so that during it is changed from forward conduction state to reverse blocking state, the Reverse recovery voltage waveform of measured diode can be got, Reverse recovery voltage peak in the Reverse recovery voltage waveform is then obtained by signal processing circuit, and it is further processed into the voltage pulse signal wide with reverse recovery time, the voltage pulse signal is after master controller digital to analog conversion, calculate reverse recovery time, further after master controller determines classification, command adapted thereto is exported to be screened to sorting circuit.Implement the present invention, its is simple and practical, and change manually detection pattern, automatic detection and the screening of diode are realized, so as to reduce detection time and human cost.
Description
Technical Field
The invention relates to the technical field of industrial automation, in particular to a device for screening diodes based on reverse recovery time.
Background
The diode is widely applied to modern power electronic equipment and is a core device for realizing efficient and rapid electric energy conversion and control of the modern power electronic equipment. The diode needs a certain time from cut-off to conduction and from conduction to cut-off, namely, a switching transient state exists, the existence of the switching transient state can cause electromagnetic interference, increase power loss and the like, the working safety and the running performance of equipment are greatly influenced, and the stability and the reliability of the performance of the diode in the high-power equipment have higher requirements, so that the selection of a proper diode is very important.
In many practical applications, high power loss generally occurs during the reverse recovery process of the diode, so that the testing of the reverse recovery characteristics, especially the reverse recovery time, is crucial when selecting the diode.
In the prior art, two methods for testing the reverse recovery time of the diode are provided: the method is simple and convenient to operate, but manual reading is needed, so that the obtained reverse recovery time error is large; and secondly, a signal generator is used for providing forward current and reverse voltage signals to act on the tested diode, a reverse recovery waveform is obtained through a load resistor, then pulse signals with the same width as the reverse recovery time are obtained through two comparators, and a high-performance, high-frequency and high-precision counter is used for realizing quick and accurate measurement.
The inventor also finds that the two methods not only have the problems, but also have the phenomena that the detection time is too long and the labor cost is too much due to the current situation based on manual detection when the detection number of the diodes is too large.
Disclosure of Invention
The technical problem to be solved by the embodiments of the present invention is to provide a device for screening diodes based on reverse recovery time, which is simple and practical, and changes a manual detection mode to realize automatic detection and screening of diodes, thereby reducing detection time and labor cost.
The embodiment of the invention provides a device for screening diodes based on reverse recovery time, which is matched with the diodes and comprises a reverse recovery time testing circuit, a signal processing circuit, a main controller and a sorting circuit which are sequentially connected; wherein,
the reverse recovery time test circuit comprises a forward current source circuit, a reverse voltage source circuit, a test standard setting circuit and a waveform test circuit, wherein the forward current source circuit is used for loading forward current pulses and modulating on a tested diode, the reverse voltage source circuit is used for loading reverse voltage pulses and modulating on the tested diode, the test standard setting circuit is used for setting a reverse recovery test standard, and the waveform test circuit is used for judging the polarity of the tested diode and acquiring the reverse recovery voltage waveform of the tested diode;
the signal processing circuit comprises a reverse recovery voltage peak detection circuit for acquiring a reverse recovery voltage peak value in a reverse recovery voltage waveform of the tested diode and a signal acquisition circuit for acquiring a voltage pulse signal with the same width as the reverse recovery time through two comparators after the reverse recovery voltage peak value is divided by a load resistor;
the main controller is used for calculating reverse recovery time after converting the voltage pulse signal into a digital signal, determining the type of the diode to be tested according to a preset reverse recovery time range, and further outputting a corresponding instruction to the sorting circuit according to the type; wherein the categories include good and bad;
the sorting circuit comprises a driving circuit and a sorting mechanism; the driving circuit is formed by a plurality of triodes and peripheral circuits thereof and is used for receiving the instruction sent by the main controller and driving the sorting mechanism to act; the sorting mechanism comprises a first channel, a second channel penetrating through the inner wall of one side of the first channel and a cutting and throwing mechanism which is positioned at the joint of the first channel and the second channel and is connected with the driving circuit; the switching mechanism is used for controlling the conduction or the disconnection of the first channel or the second channel according to the current provided by the driving circuit, so that the tested diode can flow out of one of the first channel and the second channel.
The reverse recovery voltage peak detection circuit is realized by a 1N60 type diode, a capacitor, an LM324 type operational amplifier and peripheral circuits thereof.
The signal acquisition circuit is realized by a load, a CD4066 type electronic switch and a two-stage comparison circuit; one of the comparison circuits is a circuit with double-end input and double-end output composed of a voltage feedback operational amplifier, and the other comparison circuit is a circuit with double-end input and single-end output composed of triodes.
The drive circuit in the sorting circuit is formed by a triode, a 74HC373 type temporary storage IC chip and a peripheral circuit thereof; the cutting and throwing mechanism in the sorting circuit is an electromagnet; wherein,
one end of the electromagnet is connected with an internal direct current voltage source, and the other end of the electromagnet is connected with a collector of a triode in the driving circuit.
The drive circuit in the sorting circuit is formed by a triode, a 74HC373 type temporary storage IC chip and a peripheral circuit thereof; the cutting and throwing mechanism in the sorting circuit is a single-knife double-position switch; the single-pole double-position switch is connected with a collector of a triode in the driving circuit.
The device further comprises an alarm circuit connected with the main controller, wherein the alarm circuit is realized through a light-emitting diode, a buzzer and a peripheral circuit connected with the light-emitting diode and the buzzer, and is used for giving out light and/or sounding alarm when the reverse recovery time calculated by the main controller is beyond the preset reverse recovery time range.
The embodiment of the invention has the following beneficial effects:
in the embodiment of the invention, the device can detect the reverse recovery time of the diodes through the reverse recovery time test circuit, the signal processing circuit and the main controller, and then automatically screen the diodes according to the detection structure through the sorting circuit, so that the device is simple and practical, and changes the manual detection mode, so that the detection and screening of a large number of diodes can be carried out, and the detection time and the labor cost are reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is within the scope of the present invention for those skilled in the art to obtain other drawings based on the drawings without inventive exercise.
Fig. 1 is a system structure diagram of an apparatus for screening diodes based on reverse recovery time according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the system architecture of the sorting circuit of FIG. 1;
fig. 3 is an application scenario diagram of a reverse recovery time test circuit in the device for screening diodes based on reverse recovery time according to the embodiment of the present invention;
FIG. 4 is a diagram of a reverse recovery waveform for the reverse recovery time test circuit of FIG. 3 selecting a standard output; wherein the curves (1), (2) and (3) from top to bottom are the waveforms of the cathode of the diode under test DUT and the bases of the transistors TR6 and TR5 in fig. 6, respectively.
FIG. 5 is a diagram of a reverse recovery waveform for the reverse recovery time test circuit of FIG. 3 selecting another standard output; wherein the curves (1), (2) and (3) from top to bottom are the waveforms of the cathode of the diode under test DUT and the bases of the transistors TR6 and TR5 in fig. 6, respectively.
Fig. 6 is a diagram of an application scenario of a signal processing circuit in an apparatus for screening diodes based on reverse recovery time according to an embodiment of the present invention;
fig. 7 is an application scenario diagram of a main controller in an apparatus for screening diodes based on reverse recovery time according to an embodiment of the present invention;
fig. 8 is a diagram illustrating an application scenario of a sorting circuit in an apparatus for screening diodes based on reverse recovery time according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.
As shown in fig. 1 and fig. 2, in an embodiment of the present invention, an apparatus for screening diodes based on reverse recovery time is provided, which is matched with a diode, and includes a reverse recovery time testing circuit 1, a signal processing circuit 2, a main controller 3, and a sorting circuit 4, which are connected in sequence; wherein,
the reverse recovery time test circuit 1 comprises a forward current source circuit 11 for loading forward current pulses and modulating on a diode to be tested, a reverse voltage source circuit 12 for loading reverse voltage pulses and modulating on the diode to be tested, a test standard setting circuit 13 for setting a reverse recovery test standard and a waveform test circuit 14 for judging the polarity of the diode to be tested and acquiring the reverse recovery voltage waveform of the diode to be tested, which are connected in sequence;
the signal processing circuit 2 comprises a reverse recovery voltage peak detection circuit 21 for acquiring a reverse recovery voltage peak value in a reverse recovery voltage waveform of the diode to be detected and a signal acquisition circuit 22 for acquiring a voltage pulse signal with the same width as the reverse recovery time through a two-stage comparator after the reverse recovery voltage peak value is divided by a load resistor;
the main controller 3 is used for calculating reverse recovery time after converting the voltage pulse signal into a digital signal, determining the type of the diode to be tested according to a preset reverse recovery time range, and further outputting a corresponding instruction to the sorting circuit 4 according to the type; wherein the categories include good and bad;
the sorting circuit 4 includes a drive circuit 41 and a sorting mechanism 42; the driving circuit 41 is formed by a plurality of triodes and peripheral circuits thereof, and is used for receiving an instruction sent by the main controller 3 and driving the sorting mechanism 42 to act; the sorting mechanism 42 comprises a first channel a1, a second channel a2 penetrating through the inner wall of one side of the first channel a1, and a cutting mechanism K which is positioned at the connection part of the first channel a1 and the second channel a2 and is connected with the driving circuit 41; the switching mechanism K is configured to control the first channel a1 or the second channel a2 to be turned on or off according to the current provided by the driving circuit 41, so that the diode to be tested can flow out of one of the first channel a1 and the second channel a 2.
It should be noted that the first channel a1 and the second channel a2 correspond to the class of the diode under test, respectively, so that the purpose of fast screening the diode is achieved according to the diode under test flowing out channel.
In the embodiment of the present invention, the reverse recovery voltage peak detector circuit 21 is implemented by a 1N60 type diode, a capacitor, an LM324 type operational amplifier, and peripheral circuits thereof. The signal acquisition circuit 22 is realized by a load, a CD4066 type electronic switch and a two-stage comparison circuit; one of the comparison circuits is a circuit with double-end input and double-end output composed of a voltage feedback operational amplifier, and the other comparison circuit is a circuit with double-end input and single-end output composed of triodes.
In the embodiment of the present invention, the driving circuit 41 in the sorting circuit 4 is formed by a triode, a 74HC373 type register IC chip and its peripheral circuits; the cutting and throwing mechanism in the sorting circuit 4 is an electromagnet or a single-pole double-set switch. When the switching mechanism is an electromagnet, one end of the electromagnet is connected with an internal direct current voltage source, and the other end of the electromagnet is connected with a collector of a triode in the driving circuit 41; when the switching mechanism is a single-pole double-position switch, the single-pole double-position switch is connected with the collector of the triode in the driving circuit 41.
Furthermore, the device also comprises an alarm circuit 5 connected with the main controller 3, wherein the alarm circuit 5 is realized by a light-emitting diode, a buzzer and a peripheral circuit connected with the light-emitting diode and the buzzer and is used for emitting light and/or sounding alarm when the reverse recovery time calculated by the main controller 3 is beyond the preset reverse recovery time range.
As shown in fig. 3 to fig. 8, application scenarios of the apparatus based on reverse recovery time screening diode in the embodiment of the present invention are further described:
in FIG. 3, the reverse recovery time test circuit is mainly divided into forward current pulses IFGenerating, reversing voltage pulses VRSeveral parts are generated, regulated, selected by test standard and identified by the polarity of the tested diode. The front pulse output by the P13 pin in the sub CPU chip IC6 is used for triggering an analog oscilloscope, which is not needed when the oscilloscope is digital.
The pulse with the frequency of 10kHz and the width of 2 mus from the P14 pin in an 89C2051 type auxiliary CPU chip IC6 is sent to a TC4420 type field effect tube current driver IC10 to drive an IRF511 type field effect tube TR10 to work, the driving current of the IC10 can reach 2A, and simultaneously, the output impedance of a pulse signal can be effectively reduced so as to enhance the anti-interference capability of the signal in a subsequent circuit. Output of TR10The input capacitance reaches 700pF, and can be driven when the current is more than or equal to 300 mA. The output of the drain of TR10 is the reverse voltage pulse VRAnd then sent to the anode of the diode to be tested.
The pulse from P17 pin of 89C2051 type sub CPU chip IC6 is sent to A3 pin of UNL2003 type large current Darlington array IC5, and the output end Q4 of IC5 controls the output drain current when the J306 type P channel field effect transistor TR12 is conducted, and the output drain current is sent to the anode of the tested diode. Simultaneous forward current pulse IFShould precede the reverse voltage pulse VRSufficient time to ensure that the diode under test is loaded with a reverse voltage pulse VRIs already in a forward steady state.
The high and low states of Q1 identify the positive and negative polarities of diode Dx under test. When the Q1 is in a low level state, the placing polarity of the tested diode is correct, and the measurement can be carried out; when Q1 is in high state, the polarity of diode Dx is reversed, and it is impossible to measure. The high and low state of Q2 is used to select either criterion 2 or criterion 1. When the Q2 is in low level state, the JRC19F type relay J2 selects 'Standard 2' when it is sucked, when the field effect transistor TR12 is conducted, the output drain current is loaded to the anode of the tested diode via the resistor R16, and the 'Standard 2' forward current pulse IFFor reverse voltage pulse V of 0.5ARWithout di/dt requirement, reverse pulse VRThe current is sent to the anode of the diode to be tested through a resistor R19; when the Q2 is in high level state, the relay J2 is not sucked, the 'standard 1' is selected, when the field effect transistor TR12 is conducted, the output drain current is loaded to the anode of the tested diode through the resistor R49, and the 'standard 1' forward current pulse IF1A, reverse voltage pulse VRThe leading edge of the pulse is regulated via inductors L2 and L3 (V)RDi/dt of 50A/mus or 100A/mus) and sent to the anode of the diode under test. High-low state of Q3 can select reverse voltage pulse V of' standard 1RThe di/dt speed of (J) and the high-low state of Q3 are used to control the switching state of the relay J3, and the switching state of J3 determines the reverse voltage pulse VRThe di/dt is regulated by the action of electromagnetic induction through different inductors, and the JRC19F type relay J3 is sucked and selected when the Q3 is in a low level stateSelecting 100A/mu s; when Q3 is high, J3 does not actuate selection for 50A/. mu.s. Q4 controls a J306P-channel fet TR12 (acting as an electronic switch). When Q4 is in the low state, TR12 is turned on, and R15 can act as a load for Q4. R18 can increase the leakage current of TR12, and determine the positive and negative polarity of the diode Dx to be tested. Load resistance RL-R26-1 Ω, VRV. (R19+ RL) — 30/(19+1) — 1.5A, for "standard 2", by IF0.5A offsets some, still leaving-1.0A; for "Standard 1", by IF1.0A offsets a portion, and also-0.5A.
In one embodiment, as shown in FIG. 4, at IF＝50mA，VRThe reverse recovery waveform Vrr waveform measured under the standard condition of 10V, RL-75 Ω, the waveform of the base of TR10, and the waveform of the base of TR 9;
in another embodiment, as shown in FIG. 5, at IF＝0.5A，IRThe reverse recovery waveform Vrr waveform measured under the standard condition of 75 Ω, the waveform of TR10 base, and the waveform of TR9 base are 1A.
In fig. 6, the signal processing circuit is divided into a reverse recovery voltage peak Vrrm detection circuit and a signal acquisition circuit.
The diode D2 of the 1N60 type, the capacitor C28, the LM324 type operational amplifier IC15A and the peripheral devices form a detection circuit of the reverse recovery voltage peak value of the tested diode. The interior of the LM324 type operational amplifier IC15A is a PNP transistor, and when the PNP transistor works, the current at the same phase terminal is output to the outside, so that the D2 can work, and the output impedance of the signal can be reduced. Positive pulse current IFApplying the voltage pulse V to the anode of the diode to be tested through R16 (standard 2) or R49 (standard 1), and then applying a reverse voltage pulse VRSince the reverse recovery current outputted from the negative electrode of the diode under test is also applied to the same position, the reverse recovery voltage waveform Vrr is generated as Irr · RL by flowing the reverse recovery current through the relay J1 to the load resistor R26. After the reverse recovery voltage waveform Vrr removes forward voltage through the diode D2, the small capacitor C28 performs peak detection on the reverse recovery voltage waveform to obtain reverse peak voltage Vrrm. Since the diode is charged by itself in forward conductionThe voltage is reduced, so the voltage compensation is needed before the signal is sent to a signal acquisition circuit, the output of the IC15A with the reverse recovery voltage peak value is subjected to voltage division by R13 and R14, then a potentiometer W2 is used for calibration to counteract the forward voltage drop of D2 to obtain a divided voltage of-0.1 Vrmm, then a voltage value of +0.1 Vrmm is obtained after the voltage is subjected to an inverter circuit consisting of an LM324 type operational amplifier IC15B and resistors R27 and R41, and the voltage value is sent to an IN1 pin of a TLC2543CN type A/D conversion chip IC2 of a main control circuit.
In the signal acquisition circuit, 4 switches are arranged in a CD4066 type electronic switch IC9 chip, and 5 pins of the 4 switches control 3 pins and 4 pins, and 6 pins of the 4 switches control 8 pins and 9 pins. If there is no tested diode, the 6 feet of IC9 are set to high level by the sub-CPU chip IC6, the 8 and 9 feet are connected in parallel and then grounded, so that the emitters of the output stages TR5 and TR6 of the sampling circuit are grounded and stop working, when the tested diode is placed normally, the reverse recovery voltage waveform Vrr of the tested diode is passed through two stages of comparison circuits to obtain a voltage pulse signal proportional to the reverse recovery time. The first stage is a circuit with double-end input and double-end output, and the second stage is a circuit with double-end input and single-end output. When measured using "Standard 2", the R39 voltage division yields-0.25V, which is fed from the 2 pin input of IC9, from the 1 pin output to the inverting terminal of the OPA699 type voltage feedback operational amplifier IC6A in the first stage comparator. When the voltage is measured by the standard 1, the output of the IC15A of the reverse recovery peak current detection circuit of the tested diode is divided by R13 and R14, then the divided voltage is sent to the 4 pins of the IC9, and the output is sent to the inverting terminal of an OPA699 type voltage feedback operational amplifier IC6A in the first-stage comparator of the sampling circuit from the 3 pins. In Standard 2, the fixed 30V voltage generated by TR10 is current limited via R19, canceling out the positive IFAfter 0.5A, the remaining 1A flows through the load resistor R26 to generate the reverse recovery voltage waveform Vrr. DC voltage with-0.25V voltage is distributed by R40, R38, differential comparison is carried out between the DC voltage and recovery voltage waveform Vrr in first stage comparators IC6A, IC6B through electronic switch IC9, output ends of IC6A, IC6B are amplified and input to bases of second stage comparators TR5, TR6 through common collector BJT transistors TR1, TR13 respectively, and voltage pulse proportional to reverse recovery time of the tested diode is output from loads C6, R35 of collector of TR5A signal. Since the obtained voltage pulse signal is small, if the voltage pulse signal is directly transmitted to an A/D converter chip for A/D conversion, the generated error is large, so that the voltage pulse signal needs to be amplified and output by a negative feedback amplifier consisting of an OP-07 type operational amplifier chip IC8 and peripheral devices thereof, then sent to a TLC2543CN type A/D conversion chip IC2 to be converted into a digital signal, and then sent to a 89C52 type main CPU for processing. Potentiometer W5 is used for adjusting 0, and C31 can suppress oscillation.
In fig. 7, a CPU chip IC1 of type 89C52 undertakes complex logic control and digital operation tasks of the whole machine. The main CPU chip IC1 recognizes and receives the input of the keyboard; the test and stop signals output by the main CPU chip IC1 control the sub-CPU (89C2051) chip IC6 to generate a forward pulse current IFReverse voltage pulse VRThe front pulse controls the switch of the relay to complete the diode test to obtain reverse recovery voltage Vrr; the main CPU chip IC1 controls IC2(A/D conversion chip) to test data such as power supply, reverse recovery time trr, reverse peak voltage Vrrm and the like of each part, and sends signals to the LCD for display; the 27-pin Q9 signal of the IC1 (main CPU) is connected with a diode D1 and a resistor R23, so that whether a device to be tested exists or not can be judged, and the high level is realized when the device to be tested does not exist; AN AN of a 28-pin IC1 (main CPU) is connected with AN automatic test button of AN automatic device selection circuit through a resistor R21, and when the AN is pressed, the system tests the devices one by one; when the AN is not pressed, the mechanical part continuously rotates to automatically test the pipe; the relay switching signal is also sent to UNL2003 high voltage and high current darlington array IC5 by 74HC373 type register chip IC4 to control the relay and the rotary electromagnet, so as to achieve the purpose of cooperative testing.
The input ends IN 0-IN 9 of the TLC2543CN A/D converter IC2 can detect the potential condition of each circuit and reflect the potential condition on the RT12032-1 LCD display, so that the fault can be positioned IN time and processed quickly; receiving pulse signals with the same width as the reverse recovery time trr and a reverse recovery voltage peak value Vrrm transmitted by a reverse recovery time trr processing circuit of the tested diode, completing conversion of trr pulses and Vrrm from an analog state to a digital state, then sending a conversion result to a main CPU, obtaining reverse recovery charges Qr of the tested diode through operation of a main CPU chip IC1, judging grading of the tested diode according to the reverse recovery time trr, finally sending the result to an LCD for displaying, and finally realizing automatic display of the reverse recovery time.
The TL431C type variable voltage regulator diode IC7 chip is a reference power supply of 4.095V. The operational amplifiers IC15B, IC15C, IC15D and their respective surrounding devices constitute inverters. The IC15B sends the reverse recovery voltage peak signal Vrrm ═ IrrmRL to the a/D converter IC 2; IC15C sends the +15V signal to A/D converter IC 2; IC15D sends a-30V signal to A/D converter IC 2.
The 24C02 electrically erasable PROM IC3 records the set parameters for the next boot call.
W1 is trr conversion voltage correction, W2 is Vrrm correction, W3 is reference voltage correction, W4 is LCD display clarity fine adjustment, and W5 is trr amplifier zeroing.
The 74HC373 type register IC4 not only expands the pin count of the main CPU, but also isolates the vulnerable part of the whole machine from the bus, protecting the safety of the bus information. The pin Q1 of the IC4 is connected to pins 12 and 13 (internal switches 1 and 4) of the electronic switch IC9 chip, and determines the level of the trr signal. IC5 is an amplifier/driver circuit for each relay and rotary magnet.
In fig. 8, the sorting circuit sorts the tested diodes into good and bad grades and screens the diodes by using the rotary electromagnet K. The triodes TR8 and TR15, a 74HC373 type temporary storage chip IC4 of the main controller in FIG. 5 and a UNL2003 type high-voltage-resistance and large-current Darlington array IC5 chip form a driving circuit together, and an electromagnet K is driven to rotate to select different ranges of the reverse recovery time of the tested diode; wherein, one end of the rotary electromagnet A is connected to a common power supply 24V, the +24V heavy current for the rotary electromagnet is rectified by D13 and D14, and filtered by C25 and C27; the other end of the electromagnet a is connected to the collector of the transistor TR15 via a thermistor R48.
When the reverse recovery time of the tested diode is within the preset reverse recovery time range, the electromagnet A is turned over, so that the first channel a1 is conducted, the second channel a2 is turned off, and the tested diode in a good state is automatically screened out and flows out of the first channel a 1; on the contrary, the electromagnet a is static, so that the first channel a1 is turned off, the second channel a2 is turned on, and the tested diode with the damaged state is automatically screened out to flow out of the second channel a 2.
The embodiment of the invention has the following beneficial effects:
in the embodiment of the invention, the device can detect the reverse recovery time of the diodes through the reverse recovery time test circuit, the signal processing circuit and the main controller, and then automatically screen the diodes according to the detection structure through the sorting circuit, so that the device is simple and practical, and changes the manual detection mode, so that the detection and screening of a large number of diodes can be carried out, and the detection time and the labor cost are reduced.
It will be understood by those skilled in the art that all or part of the steps in the method for implementing the above embodiments may be implemented by relevant hardware instructed by a program, and the program may be stored in a computer-readable storage medium, such as ROM/RAM, magnetic disk, optical disk, etc.
The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.
Claims (5)
1. A device for screening diodes based on reverse recovery time is matched with a tested diode and is characterized by comprising a reverse recovery time testing circuit, a signal processing circuit, a main controller and a sorting circuit which are sequentially connected; wherein,
the reverse recovery time test circuit comprises a forward current source circuit, a reverse voltage source circuit, a test standard setting circuit and a waveform test circuit, wherein the forward current source circuit is used for loading forward current pulses and modulating on a tested diode, the reverse voltage source circuit is used for loading reverse voltage pulses and modulating on the tested diode, the test standard setting circuit is used for setting a reverse recovery test standard, and the waveform test circuit is used for judging the polarity of the current diode and acquiring the reverse recovery voltage waveform of the tested diode;
the signal processing circuit comprises a reverse recovery voltage peak detection circuit for acquiring a reverse recovery voltage peak value in a reverse recovery voltage waveform of the tested diode and a signal acquisition circuit for acquiring a voltage pulse signal with the same width as the reverse recovery time through two comparators after the reverse recovery voltage peak value is divided by a load resistor; the signal acquisition circuit is realized by a load, a CD4066 type electronic switch and a two-stage comparison circuit; in the signal acquisition circuit, 4 switches are arranged in a CD4066 type electronic switch IC9 chip, 5 pins of the chip control 3 pins and 4 pins, 6 pins control 8 pins and 9 pins, if no tested diode exists, 6 pins of an IC9 are set to be high level by a sub-CPU chip IC6, the insides of the 8 pins and the 9 pins are connected in parallel and then grounded, so that emitting electrodes of output stages TR5 and TR6 of the sampling circuit are grounded and stop working, and when the tested diode is normally placed, a reverse recovery voltage waveform Vrr of the tested diode obtains a voltage pulse signal which is in direct proportion to reverse recovery time through two stages of comparison circuits;
the main controller is used for calculating reverse recovery time after converting the voltage pulse signal into a digital signal, determining the type of the diode to be tested according to a preset reverse recovery time range, and further outputting a corresponding instruction to the sorting circuit according to the type; wherein the categories include good and bad;
the sorting circuit comprises a driving circuit and a sorting mechanism; the driving circuit is formed by a plurality of triodes and peripheral circuits thereof and is used for receiving the instruction sent by the main controller and driving the sorting mechanism to act; the sorting mechanism comprises a first channel, a second channel penetrating through the inner wall of one side of the first channel and a cutting and throwing mechanism which is positioned at the joint of the first channel and the second channel and is connected with the driving circuit; the switching mechanism is used for controlling the conduction or the disconnection of the first channel or the second channel according to the current provided by the driving circuit, so that the tested diode can flow out of one of the first channel and the second channel.
2. The apparatus of claim 1, wherein the reverse recovery voltage peak detector circuit is implemented by a type 1N60 diode, a capacitor, a type LM324 operational amplifier, and their peripheral circuits.
3. The apparatus of claim 1, wherein the driving circuit of the sorting circuit is formed by a transistor, 74HC373 type register IC chip and its peripheral circuit; the cutting and throwing mechanism in the sorting circuit is an electromagnet; wherein,
one end of the electromagnet is connected with an internal direct current voltage source, and the other end of the electromagnet is connected with a collector of a triode in the driving circuit.
4. The apparatus of claim 1, wherein the driving circuit of the sorting circuit is formed by a transistor, 74HC373 type register IC chip and its peripheral circuit; the cutting and throwing mechanism in the sorting circuit is a single-knife double-position switch; the single-pole double-position switch is connected with a collector of a triode in the driving circuit.
5. The apparatus of claim 1, further comprising an alarm circuit connected to the main controller, the alarm circuit being implemented by a light emitting diode, a buzzer, and a peripheral circuit connected thereto, for emitting light and/or sounding an alarm when the reverse recovery time calculated by the main controller is outside the preset reverse recovery time range.
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| CN201610149876.1A CN105807198B (en) | 2016-03-16 | 2016-03-16 | A kind of device that diode is screened based on reverse recovery time |
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| CN105807198B true CN105807198B (en) | 2017-07-18 |
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| US3648168A (en) * | 1970-12-16 | 1972-03-07 | Honeywell Inf Systems | Apparatus for measuring reverse recovery characteristics of diodes |
| JP4663930B2 (en) * | 2001-09-12 | 2011-04-06 | 日本インター株式会社 | Reverse recovery time characteristic measuring device |
| CN101118273A (en) * | 2006-07-31 | 2008-02-06 | 中国科学院微电子研究所 | Method for measuring reverse recovery time of PIN diode |
| CN201399437Y (en) * | 2009-03-10 | 2010-02-10 | 钱卫卫 | Automatic feeding detection and classification device for high-power light-emitting diodes |
| CN201607513U (en) * | 2010-01-15 | 2010-10-13 | 深圳市瑞凌实业股份有限公司 | Simple circuit for testing reverse recovery time of diode |
| CN103264019B (en) * | 2013-04-25 | 2014-06-11 | 洛阳久德轴承模具技术有限公司 | Tapered roller surface defect detection system |
| CN104267328A (en) * | 2014-09-17 | 2015-01-07 | 哈尔滨理大晟源科技开发有限公司 | Diode reverse recovery time testing method |
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