Circuit and method for time-sharing detection of current and voltage analog quantity of lamp

Abstract

The invention discloses a circuit and a method for time-sharing detection of analog quantity of current and voltage of a lamp, belongs to the technical field of current and voltage control of a semiconductor process, and aims to carry out whole-course measurement on bulbs powered by AC (Alternating Current) or DC (Direct Current), the number of bulbs connected in series in each loop is not limited, and a single bulb or a plurality of bulbs connected in series can be detected. And current data can be used as a group of parameters to assist in judging process data. The method comprises the following steps: detecting a current value, comparing the detected current value with Spec, and if the detected current value exceeds the Spec, calculating a voltage value in a corresponding loop so as to accurately locate which lamp has a fault. According to the invention, AD two-stage multiplexing is adopted, which loop problem is positioned by current is detected firstly, and then the specific position is positioned by measuring voltage. Current and voltage values in a loop can be detected, two-stage AD sampling is adopted, the sampling efficiency is improved, the workload of an MCU is reduced, and fault positioning of each lamp is more efficient and accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor process fault detection, and relates to a circuit and method for time-sharing detection of lamp current and voltage analog quantities. Background Art

[0002] The Rapid Thermal Processing Furnace (RTP) uses halogen infrared lamps as heat sources to quickly heat wafers or materials to 300°C-1100°C, thereby eliminating stress from the internal structure of the wafer, repairing ion implantation damage, and promoting the rational distribution of impurities, thereby improving product performance.

[0003] In the RTP equipment, the wafer is heated in multiple temperature zones. Each temperature zone consists of multiple lamps. All lamps are placed directly above the wafer and installed in a dedicated lamp room with a reflector. Special tools are required to disassemble and assemble the lamps in each temperature zone. When the lamp is installed abnormally, it will be broken or short-circuited. As the use time increases, the state of the lamp will change, which is manifested as reduced luminous efficiency, thinner tungsten filament, and larger resistance. In short, the brightness of the lamp will change, and the temperature emitted will decrease, which will cause uneven heating of the wafer. Although the wafer rotates during the process, it still manifests as uneven heating at non-concentric locations of the wafer, warping, and even wafer breakage. In order not to affect the process, it is very necessary to detect the state of the lamp in real time.

[0004] In such Figure 1 In the prior art shown, the current in the lamp circuit is detected. When the current in the circuit is lower than a certain value, the comparator output changes to indicate a fault in the lamp circuit. The SCR AC power supply 001 outputs alternating current, and the waveform 002 is shown on the right. The current value in the circuit is read out after passing through the Hall sensor 003, and the waveform 004 after passing through the resistor-capacitor filter circuit is compared with the reference voltage through the comparator 005. When the SCR output is greater than a certain value, the detection circuit alarm function is turned on. When the circuit is normal, the measured value after the resistor-capacitor filter is higher than the threshold, the comparator outputs a low level, and the circuit is normal; when the lamp in the circuit is broken, the measured value after the resistor-capacitor filter is lower than the threshold, and the comparator outputs a high level, and the high level signal is given to the MCU, and an alarm is thrown.

[0005] Figure 1The disadvantages of the prior art shown are: when current flows through the lamp circuit and the measured value is greater than the threshold, the circuit is displayed as normal, and when it is lower than the threshold, an alarm is thrown. This method can only detect whether a current less than the threshold flows through the lamp, and cannot determine whether the lamp is partially short-circuited or short-circuited. It cannot determine when there is overcurrent in the circuit. When there are multiple lamps in series in the circuit, after one lamp is short-circuited, another lamp in the circuit will have overcurrent and overvoltage, and a chain reaction may occur, causing multiple lamps in the circuit to burn out. Only after the filament is burned out and the circuit is disconnected can it be determined that there is an abnormality in this circuit. This solution is not thorough enough and can only reflect the circuit break problem regionally.

[0006] like Figure 2 In the prior art shown, the voltage at both ends of each bulb is detected, and whether the lamp is faulty is determined based on the voltage value at both ends of each lamp when multiple lamps are connected in series; the voltage signal is collected at both ends of each series lamp, and the value after resistance and capacitance filtering is transmitted to ADC013 using multiplexer MUX010 to read the voltage value into the memory 012 of the MCU. For example, the voltage value of the L29 lamp is |V2-V1|, and the voltage value of the L30 lamp is |V3-V2|. When this circuit is normal, the voltages of L29 and L30 are equal or similar, within a certain Spec range. If one of the lamps has a partial filament short circuit, short circuit, or open circuit, the voltage values ​​of L29 and L30 will deviate. Once the preset Spec value is exceeded, the MCU immediately throws an alarm, thereby detecting the problem point and realizing the failure detection function. This process needs to be detected in real time and displayed on the interface.

[0007] like Figure 2 The disadvantages of the prior art shown are: this solution is only applicable when there are more than or equal to two groups of lamps in the circuit, and the test voltage method can be used. However, if there is only a single lamp in the circuit, the voltage across the lamp is always the SCR output voltage, and the alarm function can only be realized by the test current method. The number of lamps in each chamber of the RTP device is relatively large. If there are 100 lamps connected in series, there are 150 measurement points; if there are 600 lamps, the measurement points reach 900. That is, the measurement points are 1.5 times the number of lamps, which is very demanding for the MCU. The biggest problem with the above solution 2 is that as the lamp is used, the tungsten filament inside the halogen lamp will evaporate and become thinner, resulting in an increase in the internal resistance of the lamp, and the current in the circuit will decrease. The lamps in the series circuit are used synchronously, and their lifespans are reduced at the same time. According to Ohm's law, the voltage |V2-V1| of L29 and the voltage |V3-V2| of L30 remain unchanged. The voltage across the lamp will not change, resulting in test failure. Summary of the invention

[0008] Based on the technical problems existing in the prior art, the present invention provides a circuit and method for time-sharing detection of analog quantities of lamp current and voltage, which solves the problems of too many measuring points in the prior art solution, too high requirements on the MCU and inability to accurately express the complete status of the lamp group pair, thereby reducing the workload of the MCU and locating the fault of each lamp more efficiently and accurately.

[0009] According to the first aspect of the technical solution of the present invention, the present invention provides a circuit for time-sharing detection of analog quantities of lamp current and voltage, which performs full-range measurement on AC or DC powered bulbs, and has no limit on the number of bulbs in series in each circuit, and can detect a single bulb or multiple bulbs in series; and can use current data as a set of parameters to assist in determining process data; first detect the current value and compare it with the set value, and if it exceeds the set value, calculate the voltage value in the corresponding circuit, so as to accurately locate which lamp is faulty at that time.

[0010] The circuit for time-sharing detection of lamp current and voltage analog quantities includes an AC / DC adjustable power supply, a lamp failure detection board and a lamp power supply board; the AC / DC adjustable power supply is used to convert alternating current into direct current and can adjust the output voltage to meet the power supply requirements of subsequent equipment; the lamp failure detection board supplies power to the lamp through an SCR output circuit; and the lamp power supply board is used to provide installation and power supply for the lamp.

[0011] The AC / DC adjustable power supply uses thyristor variable frequency and width modulation technology to perform chopping control on the AC power supply to control the output conversion voltage. The AC / DC adjustable power supply uses a halogen lamp.

[0012] Preferably, the circuit for time-sharing detection of analog lamp current and voltage uses a Hall device to collect the lamp current signal and voltage value.

[0013] Preferably, the circuit for time-sharing detection of lamp current and voltage analog quantity is sent to the MCU through two-stage AD chip selection to judge lamp failure detection. If there is any abnormal alarm information, it is transmitted to the host computer to realize the alarm function of the lamp.

[0014] More preferably, in the two-level AD chip selection, the first-level chip selection adopts a multiplexer 8 to 2 chips; the second-level chip selection adopts a multiplexer 8 to 2 chips.

[0015] According to the second aspect of the technical solution of the present invention, the present invention provides a method for time-sharing detection of lamp current and voltage analog quantities, which adopts AD two-stage multiplexing, firstly detects the current to locate which circuit has a problem, and then detects the voltage to locate the specific position, thereby locating which lamp has an abnormality and issuing a relevant alarm.

[0016] Furthermore, the method for time-sharing detection of lamp current and voltage analog quantities includes the following steps: Step W1: Detect the current in the circuit. When the current in the circuit exceeds the set upper and lower limits, determine which circuit has a problem. Step W2: When a circuit is found to be abnormal by step W1, the voltage values ​​of three points of the circuit are detected; Step W3: Calculate the voltage value of each lamp based on the three-point voltage values ​​detected in step W2, so as to determine which lamp has a problem and issue a related alarm.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1. The present invention adopts two-stage AD sampling to optimize the circuit. The present invention reduces the real-time sampling points and reduces the requirements on the MCU.

[0018] 2. The present invention first uses a current Hall sensor to locate which circuit has an abnormality, and then specifically measures the voltage of each lamp to point out the abnormal lamp, thereby improving work efficiency.

[0019] 3. The present invention can perform full-range measurement on AC or DC powered bulbs. There is no limit on the number of bulbs in series in each circuit. A single bulb or multiple bulbs in series can be tested. And the current data can be used as a set of parameters to assist in judging process data. First, the current value is detected and compared with the Spec. If it exceeds this value, the voltage value in the corresponding circuit is calculated to accurately locate which lamp is faulty.

[0020] 4. The present invention adopts two-stage AD multiplexing, first detects the current to locate which circuit is faulty, and then measures the voltage to locate the specific position. The current and voltage values ​​in the circuit can be detected, and two-stage AD sampling is adopted to increase the sampling efficiency, reduce the workload of MCU, and locate the fault of each lamp more efficiently and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a current circuit in a detection lamp circuit in the prior art.

[0022] Figure 2 It is a schematic diagram of a voltage circuit in a detection lamp circuit in the second prior art.

[0023] Figure 3 Schematic diagram of a current detection circuit provided by the present invention.

[0024] Figure 4 It is a schematic diagram of the relationship and connection of the multiplexing circuit provided by the present invention.

[0025] Figure 5 The figure is a schematic diagram of a voltage measurement loop circuit provided by the present invention.

[0026] Description of reference numerals in the accompanying drawings: 001, SCR AC power supply; 002, Hall sensor input voltage waveform; 003, Hall sensor; 004, filtered voltage waveform; 005, comparator; 006, Lamp failure detection board; 007, Lamp power supply board; 010, multiplexer MUX; 011, CPU; 012, storage; 013, ADC; 020, AC / DC Hall sensor; 021, first-stage AD multiplexer; 022, second-stage AD multiplexer; 023, MCU; 025, chip select communication control loop; 026, AC / DC adjustable power supply; 030, first-stage multiplexer 8 to 2 chip; 031, voltage follower; 032, second-stage multiplexer 8 to communication output chip. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0029] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0030] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0031] In the prior art, whether measuring current or voltage alone in the loop, the complete state of the lamp pair cannot be accurately described. When only measuring the loop current, the abnormal state of each lamp cannot be characterized. When only measuring the voltage, there must be more than two groups of lamps in the loop, and when the performance of the lamps decays synchronously, the abnormal state of the lamps cannot be characterized. Since there are a large number of lamp pairs in the RTP device, testing current and voltage requires testing a large number of analog variables, and the amount of detection data is particularly large. When measuring voltage in a dual-lamp loop, the number of measurement points is 1.5 times the number of lamps. For devices with a large number of lamps, the MCU is heavily burdened, or even unable to bear the work. In addition, the requirements for the MCU are particularly high.

[0032] The present invention proposes an improvement plan for the problems existing in the prior art: when detecting the test loop current or lamp voltage respectively, it is not necessary to measure the voltage of each point in real time during operation, and the loop current and the intermediate value of the lamps in the series loop are detected (low-frequency measurement can be performed). When the current or intermediate voltage in the loop changes beyond the set value (Spec) range, it indicates that a lamp in the loop has failed; at this time, the voltage values ​​of other points in the loop are measured, and after each voltage in this loop is measured, calculation is performed to determine which lamp has failed.

[0033] In one embodiment, the present invention provides a method for time-sharing detection of lamp current and voltage analog quantities, which uses two-stage AD multiplexing to first detect the current to locate which circuit is faulty; and then measure the voltage to locate the specific location. Such a technical solution can detect the current and voltage values ​​in the circuit and use two-stage AD sampling to increase sampling efficiency, reduce the workload of the MCU, and locate the fault of each lamp more efficiently and accurately.

[0034] The present invention determines whether the lamp is faulty by detecting the changes in the current and voltage in the lamp circuit. The circuit adopted by the technical solution of the present invention is as follows Figure 3 The current detection circuit shown, the circuit for time-sharing detection of lamp current voltage analog quantity includes an AC / DC adjustable power supply, a lamp failure detection board and a lamp power supply board; An AC / DC adjustable power supply is used to convert alternating current (AC) into direct current (DC) and can adjust the output voltage to meet the power supply requirements of subsequent equipment; the present invention uses an AC / DC adjustable power supply instead of the AC power supply in the prior art. In one embodiment, the AC power supply is chopper-controlled using thyristor variable frequency and width modulation technology to control the output voltage of the conversion; in this embodiment, the halogen lamp is a nonlinear element and cannot be controlled by current or power, but only by voltage control, and the accuracy of voltage control is greatly improved. In another embodiment, the AC mains is first rectified and Buck-stepped (the output voltage is controlled by switching operation) to control the voltage output to the lamp.

[0035] The lamp failure detection board supplies power to the lamp through the SCR output circuit and uses the Hall device to collect the lamp current signal and voltage value. The above are sent to the MCU through two-level AD chip selection to judge the failure detection of the lamp. If there is any abnormal alarm information, it will be transmitted to the host computer to realize the alarm function of the lamp.

[0036] The lamp power supply board is used to install and power the lamp. This board is connected to the failure detection board. The main circuit is first connected to the lamp power supply board through the failure detection board to provide connection and installation between the lamp and the chamber.

[0037] Furthermore, the lamp failure detection board includes multiple AC / DC Hall sensors, two first-stage AD multiplexers 021, a second-stage AD multiplexer 022 and an MCU (microcontroller) 023. Each loop is equipped with a set of AC / DC Hall sensors. The AC / DC Hall sensor is a chip device that is specially used to measure the loop current in a group of chips. It is connected to the 24VDC power supply part and outputs 1-5V DC; the AC / DC Hall sensor is connected to the AD chip select input terminal, and the AC / DC Hall sensor is connected to an external filter circuit.

[0038] The first-stage AD multiplexer 021 is an AD multiplexer with 8 inputs and 2 outputs, that is, it only detects the current or voltage values ​​of two loops at the same time, and detects the current or voltage values ​​of the other two loops at the next moment, so as to collect the voltage or current values ​​of all loops. The output value is an AD analog value, which is transmitted to the voltage follower to isolate the second-stage AC multiplexer and keep the output value stable. The chip select pin is connected to the control output of the MCU.

[0039] The first one of the two first-stage AD multiplexers 021 is connected to the first AC / DC Hall sensor and the second AC / DC Hall sensor.

[0040] In the preferred embodiment, only two AC / DC Hall sensors and two first-stage AD multiplexers are illustrated, but the number is far more than that. Each lamp circuit needs to be equipped with an AC / DC Hall sensor for circuit current detection. A chamber contains hundreds of circuits, that is, hundreds of AC / DC Hall sensors. Since the first-stage AD multiplexer uses 8-way input to 2-way output, 8 AC / DC Hall sensors correspond to one first-stage AD multiplexer.

[0041] The second-stage AD multiplexer 022 is used to further reduce the number of AD output pins to the MCU.

[0042] Although the first-stage AD multiplexer has reduced the loop output by 4 times, the number is still large compared to the MCU, so it passes through the second-stage AD multiplexer to further reduce the AD output pins to the MCU. The input of the second-stage AD multiplexer is the value of the output of the first-stage AD multiplexer through the voltage follower output. The second-stage AD multiplexer uses 8 inputs to 2 outputs, and the communication output is sent to the MCU, which can reduce the use of MCU pins. It is equivalent to 64 AC / DC Hall sensors corresponding to one second-stage AD multiplexer.

[0043] MCU (microcontroller) 023, which is used for the output of the second-level AD multiplexer is directly connected to the input of the MCU through communication, and is used to collect the analog voltage and analog current values ​​of each circuit, and is used to detect which lamp is faulty. For a large number of first- and second-level AD multiplexers, communication is used to each AD multiplexer chip for accurate AD multiplexer function; further, the alarm function is output to the host computer in a timely manner to prompt the operator.

[0044] The present invention adopts a chip select communication control loop 025 for selecting analog quantities of the AD multiplexer. Since the first-stage AD multiplexer 021 converts 8 channels to 2 channels, a large number of channels are required and the GPIO port of the MCU cannot be used, communication is selected to control the first-stage AD multiplexer 021.

[0045] There are multiple groups of lamps installed on the lamp power supply board, such as the first group of lamps L1 and L2, the second group of lamps L3 and L4, ..., the nth group of lamps L(2n-1) and L2n, ..., the 15th group of lamps L29 and L30. Inside a chamber device, a large number of lamps will be used to make the wafer heat more evenly. Each chamber will be divided into 15 groups of lamps, and the number of lamps in each group is 8-30. Each group of lamps has an AC / DC adjustable power supply. The power, voltage and current of all the multiple groups of lamps installed on the lamp power supply board are consistent under normal conditions. Each group of lamps is distributed on the radius circle of the wafer to apply the same heat to the wafer. Each group of lamps can be controlled separately to adjust the power output.

[0046] The following further explains Figure 3 Signal flow of the circuit shown: like Figure 3 As shown, the current value in each loop is detected. No matter how many lamps are in the loop, the AC / DC adjustable power supply 026 outputs, and the AC / DC Hall sensor 020 is used to read the current value in the loop, and then filtered and rectified, and sent to the first-level AD multiplexer 021. 8 AD inputs and 2 AD outputs can be selected. Through the common enable input control bit, the corresponding AD input bit is selected to be valid. After the first-level output, it is sent to the second-level multiplexer 022 through 1Z and 2Z. AD8 inputs can be selected, and the communication output is sent to MCU023 without occupying the AD channel. After the first level continuously switches the control bit, the loop current is collected cyclically. If the number of all lamps (Lamp) in a single chamber is 600 lamps, they are used in series in pairs, divided into 20 zones, each zone has 30 lamps, 15 loops, and the number of first-level chips required is 38, and the number of chips required for the second level is 8. The second-level chip uses communication output, so that the multiplexing will reduce the resource requirements for the MCU.

[0047] The specific multiplexing circuit relationship and connection are as follows Figure 4As shown, it includes multiple groups of AD multiplexers U1, U2, ... U75, preferably the first-stage multiplexer 8 to 2 chip 030. Figure 4 The current signal shown is the current signal AD1-AD4 output by the Hall sensor after rectification and filtering. The current signal AD1-AD4 is input to 1Y0-2Y3 of the first-stage AD multiplexer (preferably the first-stage multiplexer 8 to 2 chip, using an 8-way to 2-way multiplexer, which functions to convert 8-way analog input into 2-way analog input, reducing the number of ways in the loop). S0 and S1 are chip select pins, 1Z and 2Z are output analog values, and / E is the chip select pin of the entire AD chip. The entire AD multiplexer workflow is to select different inputs according to the values ​​of S0 and S1, convert and lead to the corresponding output pins. A voltage follower 031 is set after the AD multiplexer, and after passing through the voltage follower, it is output to the input pins IN0-IN7 of the AD multiplexer U100 (preferably the second-stage multiplexer 8 to communication output chip 032), and the AD multiplexer pin SDO is the output pin of the communication SPI to the MCU. The above is the signal output process of the two-stage AD multiplexer. In this embodiment, multiple groups of corresponding second-stage AD multiplexers U100, U101, ..., U108 are set. The voltage follower 031 is used to isolate the signal interference between the two stages. The second-stage AD multiplexer 032 uses an 8-way communication output chip, which is also used to reduce the analog quantity in the loop, reduce the number of channels, and reduce the use of MCU.

[0048] For the circuit connection and measurement points of voltage measurement, two-level reset is used, the first level AD to AD, the second level AD to communication, and directly sent to the MCU. In the voltage measurement circuit, in the application of the double lamp series circuit, the voltage measurement point is 1.5 times the number of lamps, but there is no need to measure the value of each point in real time, such as Figure 5 As shown, the intermediate voltage values ​​such as V2, V5 ... V44 can be detected at a low frequency, and this voltage value is near the intermediate value of the SCR output voltage.

[0049] Figure 5 The series circuit of each group of lamps output by the SCR AC / DC power supply is shown. Voltage collection points V1, V2, V3, ..., V43, V44, V45 are set at both ends of each lamp L1, L2, L3, ..., L29, L30. Each collection point is transmitted to the first-stage AD multiplexer after voltage reduction sampling and resistance-capacitance filtering. Figure 5 The subsequent circuit and Figure 4 The same, but the voltage signal is collected.

[0050] Figure 5 It means that voltage values ​​are collected at both ends of each lamp, and the voltage of each lamp can be calculated by subtracting the voltage values ​​at both ends.

[0051] When there is a short circuit, partial short circuit, open circuit, or the overall resistance of the lamp is too large, or even an open circuit, the current will be abnormal and will exceed the upper and lower limits of the Spec value (set value), which can determine which circuit has a problem. When a certain circuit is located to be abnormal, the voltage values ​​of three points of this circuit are detected, namely, the voltages of V1, V2, V3 or V4, V5, V6 or V43, V44, V45, etc. The voltage values ​​of the three points are used to calculate the voltage value of each lamp, so as to determine which lamp has a problem and throw a relevant alarm.

[0052] In summary, first use the current transformer in the circuit to detect whether there is any abnormality in the circuit. When an abnormality occurs, locate it in this circuit, and then detect the voltage value of each point to locate which lamp has the abnormality and throw out the relevant alarm.

[0053] The main improvement of the present invention is that the method can perform full-range measurement on AC or DC powered bulbs. There is no limit on the number of bulbs in series in each circuit. A single bulb or multiple bulbs in series can be tested. And the current data can be used as a set of parameters to assist in judging the process data. First, the current value is detected and compared with the Spec. If it exceeds this value, the voltage value in the corresponding circuit is calculated, so as to accurately locate which lamp is faulty.

[0054] Furthermore, the present invention provides a method for time-sharing detection of lamp current and voltage analog quantities, which comprises the following steps: Step S1, after the SCR power supply is powered on, the analog signal is transmitted to the MCU through two-stage AD multiplexing at different time periods after being filtered and absorbed by the Hall sensor; Step S2, taking the SCR output voltage and current as reference, the lamp currents in the same group are not much different, and are compared and judged after calculation and displayed on the host computer; Step S3, if the upper and lower differences are within the Spec range, the group of lamps is considered normal; if any current in the same group exceeds the Spec range, the lamps in this circuit are considered abnormal; Step S4, according to the abnormal lamp circuit, if there is only one lamp in this circuit, then this lamp has an abnormality; if there are two lamps in this circuit in series, it is necessary to enable the voltage test circuit in this circuit to determine which lamp has a problem; Step S5, after locating the circuit with the problem, the MCU uses the correct chip select pin according to the position of the circuit in the circuit to collect the voltage value at both ends of each lamp in the circuit, and calculates the voltage value of the lamp using the difference between the two ends of the lamp; Step S6, if the series circuit is open, the loop current value will become 0, the value across the disconnected lamp will become the SCR input voltage value, and the voltage value of the intact lamp will be 0.

[0055] If this series circuit is short-circuited, the current value of this loop will increase, the voltage across the short-circuited lamp will drop to 0, and the voltage of the normal lamp will increase to the SCR output voltage; If the series circuit is partially short-circuited, the current value of this loop will increase, the voltage across the short-circuited lamp will drop beyond the Spec, and the voltage of the normal lamp will slightly increase, locating the lamp with reduced voltage as faulty; If the resistance wire in the circuit becomes thinner due to long-term use of the lamp, resulting in increased circuit resistance and smaller circuit current value, when it exceeds the Spec based on the comparison with the SCR output current, it is considered that the lamp in this circuit needs to be replaced.

[0056] The above can accurately locate which circuit and which lamp has failed for various lamp faults, thereby realizing the lamp group failure detection function.

[0057] In another embodiment, a method for time-sharing detection of lamp current and voltage analog quantities is provided, comprising the following steps: Step W1: Detect the current in the circuit. When the current in the circuit exceeds the upper and lower limits of the Spec value (set value), determine which circuit has a problem; Detect the current value in each circuit, no matter how many lamps are in the circuit, the AC / DC adjustable power supply 026 outputs, uses the AC / DC Hall sensor 020 to read the current value in the circuit, and then filters and rectifies it, and sends it to the first-level AD multiplexer 021. It can select 8 AD inputs and 2 AD outputs. Through the common enable input control bit, the corresponding AD input bit is selected to be valid.

[0058] After the first-stage output, it is sent to the second-stage multiplexer 022 through 1Z and 2Z. AD8 input is optional, and the communication output is sent to MCU023 without occupying the AD channel. After the first stage, the control bit is continuously switched to collect the current of each loop in a cycle. If the number of all lamps (Lamp) in a single chamber is 600, they are used in series in pairs, divided into 20 zones, each zone has 30 lamps, and 15 loops, the number of first-stage chips required is 38, and the number of chips required for the second stage is 8. The second-stage chip uses communication output, so the multiplexing will reduce the resource requirements for the MCU. The specific multiplexing circuit relationship and connection are as follows: Figure 4 shown.

[0059] Furthermore, in the voltage measurement circuit, in the application of the double lamp series circuit, the voltage measurement points are 1.5 times the number of lamps, but it is not necessary to measure the value of each point in real time, such as Figure 5 As shown, the intermediate voltage values ​​such as V2, V5 ... V44 can be detected at a low frequency, and this voltage value is near the intermediate value of the SCR output voltage.

[0060] When there is a short circuit, partial short circuit, open circuit, or the overall resistance of the lamp is too large, or even an open circuit, the current will be abnormal and show a Spec value that exceeds the upper and lower limits, which can be used to determine which circuit has a problem.

[0061] Step W2: When a circuit is abnormally located by step W1, the voltage values ​​at three points of the circuit are detected; in the embodiment, the voltage values ​​at the three points of the circuit are detected as point voltages such as V1, V2, V3 or V4, V5, V6 or V43, V44, V45.

[0062] Step W3: Calculate the voltage value of each lamp based on the three-point voltage values ​​detected in step W2, so as to determine which lamp has a problem and issue a related alarm.

[0063] like Figure 5 As shown, the voltage value of lamp L1 is: U L1 = |V2-V1|, UL2 = |V3-V2| … UL30 = |V45-V43|. The specific voltage value depends on the number of lamps in each group.

[0064] In summary, the present invention adopts two-stage AD multiplexing, first detects the current to locate which circuit is faulty, and then measures the voltage to locate the specific position. The current and voltage values ​​in the circuit can be detected, and two-stage AD sampling is adopted to increase the sampling efficiency, reduce the workload of the MCU, and locate the fault of each lamp more efficiently and accurately.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A circuit for detecting the analog quantity of lamp current and voltage in time division, characterized in that: For AC or DC powered bulbs, there is no limit on the number of bulbs in series in each circuit. A single bulb or multiple bulbs in series can be tested. The current data can be used as a set of parameters to assist in judging process data. The current value is first tested and compared with the set value. If it exceeds the set value, the voltage value in the corresponding circuit is calculated to accurately locate which lamp is faulty.

2. The circuit for detecting the analog quantity of lamp current and voltage in time-sharing manner according to claim 1, characterized in that: It includes an AC / DC adjustable power supply, a lamp failure detection board and a lamp power supply board; AC / DC adjustable power supply, which is used to convert AC power into DC power and can adjust the output voltage to meet the power supply requirements of subsequent equipment; A lamp failure detection board, which supplies power to the lamp through the SCR output circuit; The lamp power supply panel is used to provide installation and power supply for the lamp.

3. The circuit for detecting the analog quantity of lamp current and voltage in time-sharing manner according to claim 2, characterized in that: The AC / DC adjustable power supply uses thyristor variable frequency and width modulation technology to perform chopping control on the AC power supply to control the output conversion voltage.

4. The circuit for detecting the analog quantity of lamp current and voltage in time-sharing manner according to claim 3 is characterized in that: AC / DC adjustable power supply adopts halogen lamp.

5. The circuit for detecting the analog quantity of lamp current and voltage in time-sharing manner according to claim 3, characterized in that: Use Hall devices to collect the current signal and voltage value of the lamp.

6. The circuit for detecting the analog quantity of lamp current and voltage in time-sharing manner according to claim 3, characterized in that: After two-level AD chip selection, it is sent to the MCU for judging the failure detection of the lamp. If there is any abnormal alarm information, it will be transmitted to the host computer to realize the alarm function of the lamp.

7. The circuit for detecting the analog quantity of lamp current and voltage in time-sharing manner according to claim 6, characterized in that: In the two-level AD chip selection, the first level chip selection uses a multiplexer 8 to 2 chips.

8. The circuit for detecting the analog quantity of lamp current and voltage in time-sharing manner according to claim 6, characterized in that: In the two-level AD chip selection, the second-level chip selection uses a multiplexer 8 to 2 chip.

9. A method for time-sharing detection of lamp current and voltage analog quantity, characterized in that: Adopting two-level AD multiplexing, the current is detected first to locate which circuit has a problem, and then the voltage is detected to locate the specific position, so as to locate which lamp has an abnormality and issue a relevant alarm.

10. The method for time-sharing detection of lamp current and voltage analog quantities according to claim 9, characterized in that: It further comprises the following steps: Step W1: Detect the current in the circuit. When the current in the circuit exceeds the set upper and lower limits, determine which circuit has a problem. Step W2: When a circuit is found to be abnormal by step W1, the voltage values ​​of three points of the circuit are detected; Step W3: Calculate the voltage value of each lamp based on the three-point voltage values ​​detected in step W2, so as to determine which lamp has a problem and issue a related alarm.

Images