Laboratory DC power supply fault combined protection circuit and method

Abstract

The invention discloses a laboratory direct-current power supply fault combined protection circuit and method. The circuit comprises a plurality of MOS tubes (Q1, Q2...) which are connected in series to an output positive pole, and a plurality of MOS tubes (Q3, Q4...) which are connected in parallel between the output positive pole and the output negative pole; the four-end current sampling resistor (R1) is connected in series with an output positive electrode; the protective tube (F1) is connected in series between the MOS tubes (Q3, Q4...) and the four-terminal current sampling resistor (R1); the voltage sampling circuit is connected to the direct-current power supply output end; the voltage acquisition signal processing circuit and the current acquisition signal processing circuit are respectively connected with the positive feedback system; an overvoltage and overcurrent set value is set by the single-chip microcomputer through a DA; the over-temperature circuit detects the temperature rise of the MOS tubes (Q3, Q4...) and is used for judging whether the fuse is replaced or not. In order to realize quick response, signal processing and triggering, analog circuit construction is adopted, and software is used for realizing the functions of overvoltage and overcurrent flexible setting, sound and light alarm, fault display and the like.

Description

Technical Field

[0001] The present invention relates to a protection technology for back-end equipment when a laboratory direct current power supply fails, and in particular to a fast-response, multi-mode combined laboratory direct current power supply failure combined protection circuit and method. Background Art

[0002] Power supply is the basis for the operation of electronic equipment. It ensures that the equipment can obtain stable power supply under various load conditions through functions such as voltage and current stabilization. The protection function of the power supply can prevent the equipment from being damaged due to abnormal power and extend the service life of the equipment. In particular, the DC power supply equipment used in the laboratory may cause damage to the back-end equipment due to misoperation or internal failure of the power supply equipment.

[0003] Laboratory DC power supplies generally power some expensive electronic equipment or complex low-voltage circuits. While providing high-quality power supply, it is also necessary to protect the back-end equipment from damage when the power supply fails. Laboratory power supply failures can be manifested in overvoltage, overcurrent, overtemperature, etc., especially in the case of overvoltage, which can easily cause large-scale damage to the back-end equipment and cause huge losses. At present, some laboratory power supplies are equipped with software protection, but the software protection response time is too slow; some laboratory power supplies are equipped with hardware protection, but the protection is not comprehensive enough and can only deal with failures due to certain reasons. In view of this, the present invention is specially proposed. Summary of the invention

[0004] The purpose of the present invention is to provide a laboratory DC power supply fault joint protection circuit and method to solve the above technical problems existing in the prior art.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] The laboratory DC power supply fault joint protection circuit of the present invention is connected between the laboratory DC power supply and the electrical equipment, and comprises:

[0007] Multiple MOS tubes (Q1, Q2...) are connected in series to the positive output, and multiple MOS tubes (Q3, Q4...) are connected in parallel between the positive and negative outputs;

[0008] The four-terminal current sampling resistor (R1) is connected in series with the output positive;

[0009] The fuse (F1) is connected in series between the MOS tubes (Q3, Q4...) and the four-terminal current sampling resistor (R1).

[0010] The method for implementing laboratory DC power supply failure protection by the above laboratory DC power supply failure joint protection circuit includes:

[0011] The laboratory DC power supply is connected to the circuit through the input terminal, the voltage and current sampling circuits start working, and the two sets of switches wait for the switching signal;

[0012] According to the overvoltage information of the voltage sampling circuit, the two groups of MOS tubes are jointly protected according to the timing;

[0013] According to the over-current information of the current sampling circuit, the two groups of MOS tubes are jointly protected according to the timing;

[0014] The fuse is the last line of defense to ensure that subsequent equipment and circuits are not damaged.

[0015] Compared with the prior art, the laboratory DC power supply fault joint protection circuit and method provided by the present invention solves the following difficulties:

[0016] When a fault occurs in the laboratory DC power supply, including overvoltage / overcurrent caused by misoperation, overvoltage / overcurrent output caused by open-loop power supply, and overvoltage / overcurrent output caused by power supply explosion, the fault protection circuit can respond quickly to protect the safety of subsequent equipment and circuits.

[0017] The present invention can well solve various faults of laboratory direct current power supply caused by different reasons, and the fault protection circuit can ensure that the subsequent equipment is not damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the principle of a laboratory DC power supply fault joint protection circuit according to an embodiment of the present invention; DETAILED DESCRIPTION

[0019] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, which does not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0020] First, the terms that may be used in this article are explained as follows:

[0021] The term “and / or” means that either or both of them can be realized at the same time. For example, X and / or Y means both “X” or “Y” and “X and Y”.

[0022] The terms "include", "comprises", "contains", "has" or other descriptions with similar semantics should be interpreted as non-exclusive inclusion. For example, including certain technical feature elements (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, procedures, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or products, etc.) should be interpreted as including not only certain technical feature elements explicitly listed, but also other technical feature elements known in the art that are not explicitly listed.

[0023] The term "consisting of..." means excluding any technical feature elements not explicitly listed. If this term is used in a claim, it will make the claim closed, so that it does not contain technical feature elements other than the technical feature elements explicitly listed, except for the conventional impurities related to them. If this term only appears in a clause of a claim, it only limits the elements explicitly listed in the clause, and the elements recorded in other clauses are not excluded from the overall claim.

[0024] The contents not described in detail in the examples of the present invention belong to the prior art known to professionals in the field. If no specific conditions are specified in the examples of the present invention, the conditions are carried out according to the conventional conditions in the field or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used in the examples of the present invention, they are all conventional products that can be purchased commercially.

[0025] The laboratory DC power supply fault joint protection circuit of the present invention is connected between the laboratory DC power supply and the electrical equipment, and comprises:

[0026] Multiple MOS tubes (Q1, Q2...) are connected in series to the positive output, and multiple MOS tubes (Q3, Q4...) are connected in parallel between the positive and negative outputs;

[0027] The four-terminal current sampling resistor (R1) is connected in series with the output positive;

[0028] The fuse (F1) is connected in series between the MOS tubes (Q3, Q4...) and the four-terminal current sampling resistor (R1).

[0029] The voltage detection circuit is connected to the output end of the DC power supply; the current detection circuit is connected to the four-terminal current sampling resistor (R1);

[0030] The voltage and current detection signal processing circuits are respectively connected to the positive feedback circuit;

[0031] The overvoltage and overcurrent setting values ​​are set by the microcontroller through DA;

[0032] The over-temperature detection circuit detects the temperature rise of the MOS tube (Q3, Q4...) to determine whether to replace the fuse.

[0033] Each group of MOS tubes is connected to a driving circuit;

[0034] According to the voltage detection information and the current detection information, the MOS tube is driven or turned off to realize fault protection.

[0035] By controlling MOS tubes (Q1, Q2...) and MOS tubes (Q3, Q4...), the protection of laboratory back-end equipment and circuits is achieved.

[0036] The method for realizing laboratory DC power supply failure protection by the above-mentioned laboratory DC power supply failure joint protection circuit comprises:

[0037] The laboratory DC power supply is connected to the circuit through the input terminal, the voltage and current sampling circuits start working, and the two sets of switches wait for the switching signal;

[0038] According to the overvoltage information of the voltage sampling circuit, the two groups of MOS tubes are jointly protected according to the timing.

[0039] According to the over-current information of the current sampling circuit, the two groups of MOS tubes are jointly protected according to the timing.

[0040] The fuse is the last line of defense to ensure that subsequent equipment and circuits are not damaged.

[0041] In summary, it can be seen that the laboratory DC power supply fault joint protection circuit and method of the embodiment of the present invention can solve the DC power supply used in the laboratory due to overvoltage / overcurrent caused by misoperation, overvoltage / overcurrent output caused by open loop power supply, and overvoltage / overcurrent output caused by power supply damage. The power supply fault joint protection circuit can respond quickly to protect the safety of subsequent equipment and circuits.

[0042] In order to more clearly demonstrate the technical solution and technical effects provided by the present invention, the embodiments of the present invention are described in detail with specific embodiments below.

[0043] Example 1

[0044] like Figure 1 As shown:

[0045] A DC power supply fault joint protection for laboratory use, comprising: a plurality of MOS tubes (Q1, Q2...) connected in series to the output positive, a plurality of MOS tubes (Q3, Q4...) connected in parallel between the output positive and negative; a four-terminal current sampling resistor (R1) connected in series to the output positive; a fuse tube (F1) connected in series between the MOS tubes (Q3, Q4...) and the four-terminal current sampling resistor (R1); a voltage sampling circuit connected to the DC power supply output terminal; a voltage and current acquisition signal processing circuit respectively connected to a positive feedback system; an overvoltage and overcurrent setting value is set by a single-chip microcomputer through a DA; an overtemperature circuit detects the temperature rise of the MOS tubes (Q3, Q4...) to determine whether to replace the fuse. In order to achieve rapid response, the present invention adopts analog circuit construction for signal processing and triggering, and software is used to realize functions such as flexible setting of overvoltage and overcurrent, sound and light alarm, and fault display.

[0046] The output end of the laboratory DC power supply is connected to this circuit, and the output of this circuit is connected to the subsequent equipment or circuit. The auxiliary power supply supplies power to the low-voltage circuit of the entire circuit, and the fault joint protection circuit starts to work. The following will describe the circuit working process in three cases: overvoltage / overcurrent caused by misoperation, overvoltage / overcurrent output caused by open-loop power supply, and overvoltage / overcurrent output caused by power failure.

[0047] The DC power supply used in the laboratory generally has the function of constant voltage / constant current output. If the output voltage is overvoltage due to misoperation, it means that the output current is within the controllable range. Then the voltage detection circuit detects the overvoltage signal, and generates an error signal by comparing it with the overvoltage setting value. After the positive feedback circuit and the timing circuit, the MOS tube (Q3, Q4...) is driven first, and the MOS tube (Q3, Q4...) changes from the off state to the on state, the output is short-circuited, and the laboratory DC power supply enters the constant current state, and the subsequent equipment and circuits will not be damaged due to overvoltage. Then the drive of the MOS tube (Q1, Q2...) is turned off, and the MOS tube (Q1, Q2...) changes from the on state to the off state, disconnecting the laboratory DC power supply output from the subsequent equipment or circuit, jointly ensuring the safety of the subsequent equipment and circuit, and transmitting the fault signal to the single-chip microcomputer to trigger the overvoltage alarm.

[0048] If the output overcurrent is caused by misoperation, the current detection circuit detects the overcurrent signal through the four-terminal current sampling resistor (R1), and generates an error signal by comparing it with the overcurrent setting value. After the positive feedback circuit and the timing circuit, the MOS tube (Q3, Q4...) is driven first, and the MOS tube (Q3, Q4...) changes from the off state to the on state, the output is short-circuited, and the output current flowing into the subsequent equipment or circuit is bypassed. Then the drive of the MOS tube (Q1, Q2...) is turned off, and the MOS tube (Q1, Q2...) changes from the on state to the off state, disconnecting the laboratory DC power supply output from the subsequent equipment or circuit, jointly ensuring the safety of the subsequent equipment and circuit, and transmitting the fault signal to the microcontroller to trigger the overcurrent alarm.

[0049] If the laboratory DC power supply output is overvoltage due to open loop power supply, it means that the power supply output current is in an uncontrollable range. Then the voltage detection circuit detects the overvoltage signal, and generates an error signal by comparing it with the overvoltage setting value. After the positive feedback circuit and the timing circuit, the MOS tube (Q3, Q4...) is driven first, and the MOS tube (Q3, Q4...) changes from the off state to the on state, and the output is short-circuited, and the subsequent equipment and circuit will not be damaged due to overvoltage. Then the drive of the MOS tube (Q1, Q2...) is turned off, and the MOS tube (Q1, Q2...) changes from the on state to the off state, disconnecting the laboratory DC power supply output from the subsequent equipment or circuit, jointly ensuring the safety of the subsequent equipment and circuit. And transmit the fault signal to the microcontroller, triggering the overcurrent alarm. Although the on / off time of the MOS tubes (Q3, Q4...) and MOS tubes (Q1, Q2...) is very short, the output current is uncontrollable and may cause the MOS tubes (Q3, Q4...) to overheat and be damaged. At this time, the fuse (F1) will melt before the MOS tubes (Q3, Q4...), which not only disconnects the laboratory DC power supply output from the subsequent equipment or circuit, but also protects the MOS tubes (Q3, Q4...) from damage, and prompts to replace the fuse through temperature detection.

[0050] If the laboratory DC power supply output overcurrent is caused by the open loop of the power supply, the current detection circuit detects the overcurrent signal through the four-terminal current sampling resistor (R1), and generates an error signal by comparing it with the overcurrent setting value. After the positive feedback circuit and the timing circuit, the MOS tube (Q3, Q4...) is driven preferentially, and the MOS tube (Q3, Q4...) changes from the off state to the on state, the output is short-circuited, and the output current flowing into the subsequent equipment or circuit is bypassed, and then the drive of the MOS tube (Q1, Q2...) is turned off, and the MOS tube (Q1, Q2...) changes from the on state to the off state, disconnecting the laboratory DC power supply output from the subsequent equipment or circuit, jointly ensuring the safety of the subsequent equipment and circuit, and transmitting the fault signal to the microcontroller to trigger the overcurrent alarm. Although the on / off time of the MOS tubes (Q3, Q4...) and MOS tubes (Q1, Q2...) is very short, the output current is too large, which may cause the MOS tubes (Q3, Q4...) to overheat and be damaged. At this time, the fuse (F1) will melt before the MOS tubes (Q3, Q4...), which not only disconnects the laboratory DC power supply output from the subsequent equipment or circuit, but also protects the MOS tubes (Q3, Q4...) from damage, and prompts to replace the fuse through temperature detection.

[0051] The overvoltage / overcurrent output caused by the explosion of the laboratory DC power supply. At this time, the DC output voltage and output current are uncontrollable and may far exceed the overvoltage / overcurrent output value caused by the open loop. The voltage detection circuit and the current detection circuit generate an error signal by comparing with the voltage and current set values. After the positive feedback circuit and the timing circuit, the MOS tube (Q3, Q4...) is driven first. The MOS tube (Q3, Q4...) changes from the off state to the on state, the output is short-circuited, and the output current flowing into the subsequent equipment or circuit is bypassed. Then the drive of the MOS tube (Q1, Q2...) is turned off, and the MOS tube (Q1, Q2...) changes from the on state to the off state, disconnecting the laboratory DC power supply output from the subsequent equipment or circuit, jointly ensuring the safety of the subsequent equipment and circuit, and transmitting the fault signal to the microcontroller to trigger the fault alarm. Since the output voltage and output current may far exceed the overvoltage / overcurrent output value caused by the open loop, the driver of the MOS tube (Q1, Q2...), the MOS tube (Q3, Q4...) and the fuse may be damaged. However, the joint protection mechanism can effectively protect the subsequent equipment or circuit from damage. At this time, the entire fault joint protection module needs to be replaced.

[0052] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims. The information disclosed in the background technology section of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or in any form that the information constitutes prior art known to those skilled in the art.

Claims

1. A laboratory DC power supply fault joint protection circuit, which is connected between the laboratory DC power supply and the electrical equipment, characterized in that: include: Multiple MOS tubes (Q1, Q2...) are connected in series to the positive output, and multiple MOS tubes (Q3, Q4...) are connected in parallel between the positive and negative outputs; The four-terminal current sampling resistor (R1) is connected in series with the output positive; The fuse (F1) is connected in series between the MOS tubes (Q3, Q4...) and the four-terminal current sampling resistor (R1).

2. The laboratory DC power supply fault joint protection circuit according to claim 1 is characterized in that: The voltage detection circuit is connected to the output end of the DC power supply; the current detection circuit is connected to the four-terminal current sampling resistor (R1); The voltage and current detection signal processing circuits are respectively connected to the positive feedback circuit; The overvoltage and overcurrent setting values ​​are set by the microcontroller through DA; The over-temperature detection circuit detects the temperature rise of the MOS tube (Q3, Q4...) to determine whether to replace the fuse.

3. The laboratory DC power supply fault joint protection circuit according to claim 2 is characterized in that: Each group of MOS tubes is connected to a driving circuit; According to the voltage detection information and the current detection information, the MOS tube is driven or turned off to realize fault protection.

4. The laboratory DC power supply fault joint protection circuit according to claim 3 is characterized in that: By controlling MOS tubes (Q1, Q2...) and MOS tubes (Q3, Q4...), the protection of laboratory back-end equipment and circuits is achieved.

5. A method for implementing laboratory DC power supply failure protection by using the laboratory DC power supply failure joint protection circuit according to any one of claims 1 to 4, characterized in that: The laboratory DC power supply is connected to the circuit through the input terminal, the voltage and current sampling circuits start working, and the two sets of switches wait for the switching signal; According to the overvoltage information of the voltage sampling circuit, the two groups of MOS tubes are jointly protected according to the timing. According to the over-current information of the current sampling circuit, the two groups of MOS tubes are jointly protected according to the timing. The fuse is the last line of defense to ensure that subsequent equipment and circuits are not damaged.

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