Rapid hardware protection circuit with output overvoltage and overcurrent following setting

Abstract

The utility model discloses a rapid hardware protection circuit with output overvoltage and overcurrent following setting, which is characterized in that a bias voltage of Vbias added to a given output voltage Vset is used as a reference voltage for sampling comparison with the output voltage, and a bias voltage of Ibias added to a given output current Iset is used as a reference voltage for sampling comparison with the output current. According to the invention, the reference voltage of the output overvoltage comparator and the reference voltage of the output overcurrent comparator are both larger than the sampling values of the voltage and the current in the normal output state, the output states of the output overvoltage comparator and the output overcurrent comparator are both normal states during normal work, and when an overvoltage threshold value and an overcurrent threshold value exceeding the overvoltage or overcurrent reference are output, the comparator turns over to trigger hardware shutdown.

Description

Technical Field

[0001] The utility model relates to a hardware protection circuit, in particular to a fast hardware protection circuit with output overvoltage and overcurrent following setting. Background Art

[0002] With the rapid development of power electronics technology, DC power supply instruments have been widely used in defense, aerospace, consumer electronics, communications, new energy, inverter and other industries. Some DC power supply equipment is very sensitive to power supply overvoltage. In some use environments, in order to avoid damage to power equipment due to DC power supply instrument failure, the DC power supply instrument can quickly shut down the power supply for protection after the voltage or current exceeds the set value, so as to avoid the power equipment from being damaged by overvoltage or overcurrent after the DC power supply instrument fails. Some power equipment has high requirements for power supply reliability due to its high cost and added value. Existing DC power supply instruments usually use the method of manually setting fixed values ​​on the front panel to perform maximum value protection. Since the software protection has a slow response speed and cannot provide fast protection, it may cause damage to the power equipment and fail to meet the demand for reliable protection.

[0003] At present, it is difficult to find hardware fast protection circuit devices that can achieve overvoltage and overcurrent following settings in the market. The common method is to use the front panel to set the protection threshold to achieve output overvoltage protection by software. The advantage of this protection method is that there is no need to add additional circuits. The original sampling circuit is used to compare the sampled voltage and current with the overvoltage and overcurrent protection thresholds set by the front panel through software. If it is greater than the threshold set by the front panel, it is considered that protection is required and the shutdown operation is performed. Due to the influence of software running speed, it is difficult to achieve fast protection. Some sensitive electrical equipment may be damaged before overvoltage protection and cannot play a reliable protection role. This method can be used when some electrical equipment is not sensitive to overvoltage. Another achievable hardware overvoltage and overcurrent protection circuit uses a fixed protection threshold to achieve fast protection, but the disadvantage is that it cannot follow the set value for protection. When the DC power supply instrument fails, it is very easy to cause damage to the electrical equipment, causing significant economic losses to the user. Therefore, it is necessary to achieve fast hardware protection of overvoltage and overcurrent following settings.

[0004] The so-called output overvoltage and overcurrent follow-up setting fast hardware protection circuit design ensures that the DC power supply instrument can quickly realize shutdown protection when the voltage and current exceed the abnormal setting, avoiding damage to the electrical equipment and causing unnecessary losses to the user. Therefore, the research on both following the set voltage and current values ​​and realizing fast protection has become the key to technical research.

[0005] Existing overvoltage and overcurrent protection implementation scheme 1:

[0006] The user of the DC instrument power supply sets the OVP and OCP protection thresholds through the front panel, and turns on the output overvoltage and overcurrent protection to realize the output overvoltage protection function. The user needs to set the overvoltage and overcurrent protection thresholds according to the input voltage and current of the power load each time. The software compares the output voltage and current with the output overvoltage and overcurrent protection thresholds set on the front panel. When the output voltage and current are higher than the set output overvoltage and overcurrent protection thresholds, the software turns off the output to realize output overvoltage and overcurrent protection. The advantage is that the user can flexibly set the protection threshold.

[0007] Disadvantages of overvoltage and overcurrent protection scheme 1:

[0008] 1) Software-implemented protection cannot provide protection when the power load is sensitive due to the slow software response speed, and cannot achieve fast output overvoltage and overcurrent protection;

[0009] 2) It is necessary to set the OVP and OCP protection thresholds according to the power load each time, and it is impossible to implement a protection method that follows the set value.

[0010] Existing overvoltage and overcurrent protection implementation scheme 2:

[0011] like Figure 1As shown, the output overvoltage protection reference is given by OV-REF, R226 is used as the RC filter resistor of the output overvoltage protection reference given by OV-REF, C95 is used as the RC filter capacitor of the output overvoltage protection reference, V-back is the output voltage sampling input terminal, R179 is the input RC filter resistor of the output voltage sampling, C69 is the filter capacitor of the output voltage sampling, R182 is the input resistor of the output overvoltage protection comparator inverting input terminal, D6 is the unidirectional hysteresis diode of the unidirectional hysteresis comparator at the inverting input terminal of the output overvoltage protection comparator, R168 is the unidirectional hysteresis resistor, when V-Back detects that the output voltage is greater than the overvoltage threshold of OV-REF, the A5B comparator flips from the original low level to the high level and pulls up the OVOCP protection through D13 to trigger the hardware output overvoltage protection, through OC-REF Given an output overcurrent protection reference, R253 is used as an RC filter resistor for the output overcurrent protection reference given by OC-REF, C111 is used as an RC filter capacitor for the output overcurrent protection reference, I-back is the output current sampling input terminal, R242 is the input RC filter resistor for the output current sampling, C106 is the filter capacitor for the output current sampling, R244 is the input resistor for the output overcurrent protection comparator non-inverting input terminal, D14 is the unidirectional hysteresis diode of the unidirectional hysteresis comparator at the non-inverting input terminal of the output overcurrent protection comparator, R240 is the unidirectional hysteresis resistor, when I-back detects that the output current is greater than the overvoltage threshold of OC-REF, the A5A comparator flips from the original low level to the high level and triggers the hardware output overcurrent protection by pulling up the OVOCP protection through D7. This solution can achieve fast output overvoltage and overcurrent protection.

[0012] Disadvantages of overvoltage and overcurrent protection scheme 2:

[0013] This method can only set a maximum value for output overvoltage and overcurrent protection through hardware, which cannot satisfy the user's ability to arbitrarily set the output voltage and current protection values ​​according to the power supply load.

[0014] In view of this, the present utility model is proposed. Utility Model Content

[0015] The utility model aims to provide a fast hardware protection circuit with output overvoltage and overcurrent following setting, so as to solve the above technical problems existing in the prior art.

[0016] The purpose of this utility model is achieved through the following technical solutions:

[0017] The utility model provides a fast hardware protection circuit for output overvoltage and overcurrent following setting, comprising:

[0018] Vset is the output voltage reference, connected to R221, R221 and C120 form an RC filter and connected to the A6B non-inverting input terminal, the A6B inverting input terminal is connected to the op amp output to form a voltage follower, and the output voltage reference is connected to R224 after passing through the voltage follower;

[0019] R224, R219, R229, R186, and A6A form an adder. R224 is connected to the non-inverting input of A6A and to R219. The other end of R219 is connected to the bias voltage Vbias+, which is used as the output overvoltage protection threshold setting. After summing with Vset, it is used as the reference point for overvoltage protection.

[0020] One end of R229 is grounded, and the other end is connected to the inverting input of A6A. R186 is connected between the inverting input of A6A and the output of the op amp to complete the summation of Vset and Vbias+ as a reference for overvoltage protection. The output of the A6A op amp is connected to R226, and the other end of R226 is connected to C95 and R184.

[0021] R226 and C95 form an RC filter, the other end of C95 is grounded, the other end of R184 is the inverting input of the A5B comparator, V-Back is the output voltage sampling, V-Back is connected to R179 and C69 to form an RC filter, after filtering, the series resistor R182 is connected to the non-inverting input of the A5B comparator and the cathode of the unidirectional hysteresis diode D6, the anode of D6 is connected to one end of R168, the other end of R168 is connected to the output of the A5B op amp, the output of the A5B op amp is connected to the anode of D13, and the cathode of D13 triggers the hardware shutdown.

[0022] Compared with the prior art, the output overvoltage and overcurrent fast hardware protection circuit provided by the utility model follows the settings, and implements a fast hardware protection solution that follows the settings by using the existing voltage and current setting method and the hardware increasing bias method. There is no need for the user to repeatedly set the protection threshold; it can achieve the output overvoltage and overcurrent fast protection function that follows the settings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the second overvoltage and overcurrent protection implementation scheme of the prior art;

[0024] Figure 2 A schematic diagram of the structure of a fast hardware protection circuit for output overvoltage and overcurrent following settings provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the utility model in conjunction with the drawings in the embodiments of the utility model; it is obvious that the described embodiments are only part of the embodiments of the utility model, not all of the embodiments, which does not constitute a limitation of the utility model. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the utility model.

[0026] First, the terms that may be used in this article are explained as follows:

[0027] 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”.

[0028] The contents not described in detail in the examples of the present utility model belong to the prior art known to professionals in the field. If no specific conditions are specified in the examples of the present utility model, the conditions are carried out according to the conventional conditions in the field or the conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments used in the examples of the present utility model are not specified, they are all conventional products that can be purchased commercially.

[0029] The utility model provides a fast hardware protection circuit for output overvoltage and overcurrent following setting, comprising:

[0030] Vset is the output voltage reference, connected to R221, R221 and C120 form an RC filter and connected to the A6B non-inverting input terminal, the A6B inverting input terminal is connected to the op amp output to form a voltage follower, and the output voltage reference is connected to R224 after passing through the voltage follower;

[0031] R224, R219, R229, R186, and A6A form an adder. R224 is connected to the non-inverting input of A6A and to R219. The other end of R219 is connected to the bias voltage Vbias+, which is used as the output overvoltage protection threshold setting. After summing with Vset, it is used as the reference point for overvoltage protection.

[0032] One end of R229 is grounded, and the other end is connected to the inverting input of A6A. R186 is connected between the inverting input of A6A and the output of the op amp to complete the summation of Vset and Vbias+ as a reference for overvoltage protection. The output of the A6A op amp is connected to R226, and the other end of R226 is connected to C95 and R184.

[0033] R226 and C95 form an RC filter, the other end of C95 is grounded, the other end of R184 is the inverting input of the A5B comparator, V-Back is the output voltage sampling, V-Back is connected to R179 and C69 to form an RC filter, after filtering, the series resistor R182 is connected to the non-inverting input of the A5B comparator and the cathode of the unidirectional hysteresis diode D6, the anode of D6 is connected to one end of R168, the other end of R168 is connected to the output of the A5B op amp, the output of the A5B op amp is connected to the anode of D13, and the cathode of D13 triggers the hardware shutdown.

[0034] Iset is the output current reference, connected to R251. R251 and C121 form an RC filter and are connected to the A9B non-inverting input terminal. The A9B inverting input terminal is connected to the op amp output to form a voltage follower. The output current reference is connected to R252 after passing through the voltage follower.

[0035] R252, R250, R254, R257, and A9A form an adder. R252 is connected to the non-inverting input of A9A and to R250. The other end of R250 is connected to the bias voltage Ibias+, which is used as the output over-current protection threshold setting. After summing with Iset, it is used as the reference point for over-current protection.

[0036] One end of R254 is grounded, and the other end is connected to the inverting input of A9A. R257 is connected between the inverting input of A9A and the output of the op amp to complete the summation of Iset and Ibias+ as a reference for overcurrent protection. The output of the A9A op amp is connected to R253, and the other end of R253 is connected to C111 and R249.

[0037] R253 and C111 form an RC filter, the other end of C111 is grounded, the other end of R249 is the inverting input of the A5A comparator, I-Back is the output current sampling, I-Back is connected to R242 and C106 to form an RC filter, after filtering, the series resistor R244 is connected to the non-inverting input of the A5A comparator and the cathode of the unidirectional hysteresis diode D14, the anode of D14 is connected to one end of R240, the other end of R240 is connected to the output of the A5A op amp, the output of the A5A op amp is connected to the anode of D7, and the cathode of D7 triggers the hardware shutdown.

[0038] In summary, it can be seen that the output overvoltage and overcurrent follow-up setting fast hardware protection circuit of the embodiment of the utility model uses the existing voltage and current setting method plus the hardware bias increase method to implement the follow-up setting fast hardware protection solution, without the user having to repeatedly set the protection threshold; it can realize the follow-up setting output overvoltage and overcurrent fast protection function.

[0039] 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.

[0040] Example 1

[0041] The fast hardware protection circuit for output overvoltage and overcurrent following setting is based on the circuit scheme 2 of the prior art by simply changing the circuit principle. The output voltage given Vset is increased by the bias voltage of Vbias as the reference voltage for comparison with the output voltage sampling, and the output current given Iset is increased by the bias voltage of Ibias as the reference voltage for comparison with the output current sampling. The reference voltages of the output overvoltage and overcurrent comparators are both greater than the sampling values ​​of the voltage and current under the normal output state, ensuring that the output states of the output overvoltage and overcurrent comparators are both normal during normal operation. When the output exceeds the overvoltage or overcurrent threshold of the overvoltage or overcurrent reference, the comparator flips to trigger the hardware shutdown.

[0042] The output overvoltage and overcurrent follow-up fast hardware protection circuit is shown in Figure 2 As shown:

[0043] Vset is the output voltage reference, connected to R221. R221 and C120 form an RC filter and are connected to the A6B non-inverting input. The A6B inverting input is connected to the op amp output to form a voltage follower. The output voltage reference is connected to R224 after the voltage follower. R224, R219, R229, R186, and A6A form an adder. R224 is connected to the A6A non-inverting input and is also connected to R219. The other end of R219 is connected to the bias voltage Vbias+ as the output overvoltage protection threshold setting. After summing with Vset, it is used as the reference point for overvoltage protection. One end of R229 is grounded and the other end is connected to the reverse input of A6A. R186 is connected across the reverse input of A6A and the op amp. Between the outputs, the summation of Vset and Vbias+ is completed as a reference for overvoltage protection. The output of the A6A op amp is connected to R226, and the other end of R226 is connected to C95 and R184. R226 and C95 form an RC filter. The other end of C95 is grounded, and the other end of R184 is the inverting input of the A5B comparator. V-Back is the output voltage sampling, and V-Back is connected to R179 and C69 to form an RC filter. After filtering, the series resistor R182 is connected to the non-inverting input of the A5B comparator and the cathode of the unidirectional hysteresis diode D6. The anode is connected to pin 1 of R168, and pin 2 of R168 is connected to the output of the A5B op amp. The output of the A5B op amp is connected to the anode of D13, and the cathode of D13 triggers the hardware shutdown.

[0044] Iset is the output current reference, connected to R251. R251 and C121 form an RC filter and are connected to the A9B non-inverting input. The A9B inverting input is connected to the op amp output to form a voltage follower. The output current reference is connected to R252 after the voltage follower. R252, R250, R254, R257, and A9A form an adder. R252 is connected to the A9A non-inverting input and is also connected to R250. The other end of R250 is connected to the bias voltage Ibias+ as the output over-current protection threshold setting. After summing with Iset, it is used as the reference point for over-current protection. One end of R254 is grounded and the other end is connected to the A9A reverse input. R257 is connected across the A9A reverse input and the op amp output. The summation of Iset and Ibias+ is used as a reference for overcurrent protection. The output of the A9A op amp is connected to R253, and the other end of R253 is connected to C111 and R249. R253 and C111 form an RC filter. The other end of C111 is grounded, and the other end of R249 is the inverting input of the A5A comparator. I-Back is the output current sampling. I-Back is connected to R242 and C106 to form an RC filter. After filtering, the series resistor R244 is connected to the non-inverting input of the A5A comparator and the cathode of the unidirectional hysteresis diode D14. The anode is connected to pin 1 of R240, and pin 2 of R240 is connected to the output of the A5A op amp. The output of the A5A op amp is connected to the anode of D7, and the cathode of D7 triggers the hardware shutdown.

[0045] Beneficial effects of the utility model:

[0046] 1) When the user has high requirements on power supply reliability, this circuit can quickly and reliably avoid overvoltage and overcurrent damage to electrical equipment caused by DC power supply instrument failure, and avoid economic losses and time waste caused by the use of equipment.

[0047] 2) The space waste caused by adding external protection devices and the disadvantage of being unable to follow the changes of set values ​​can be omitted.

[0048] The key technical points of the utility model are:

[0049] The voltage and current given references and the increase of bias are used as the references for judging output overvoltage and overcurrent to realize the hardware fast output overvoltage and overcurrent protection method that follows the set values, which simply and conveniently realizes the protection method that follows the set voltage and current.

[0050] This circuit uses the existing voltage and current setting method and the hardware to increase the bias to achieve a fast hardware protection solution that follows the setting, without the user having to repeatedly set the protection threshold;

[0051] The above is only a preferred specific implementation of the utility model, but the protection scope of the utility model 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 utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model 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 utility model, 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 fast hardware protection circuit with output overvoltage and overcurrent following setting, characterized in that: include: Vset is the output voltage reference, connected to R221, R221 and C120 form an RC filter and connected to the A6B non-inverting input terminal, the A6B inverting input terminal is connected to the op amp output to form a voltage follower, and the output voltage reference is connected to R224 after passing through the voltage follower; R224, R219, R229, R186, and A6A form an adder. R224 is connected to the non-inverting input of A6A and to R219. The other end of R219 is connected to the bias voltage Vbias+, which is used as the output overvoltage protection threshold setting. After summing with Vset, it is used as the reference point for overvoltage protection. One end of R229 is grounded, and the other end is connected to the inverting input of A6A. R186 is connected between the inverting input of A6A and the output of the op amp to complete the summation of Vset and Vbias+ as a reference for overvoltage protection. The output of the A6A op amp is connected to R226, and the other end of R226 is connected to C95 and R184. R226 and C95 form an RC filter, the other end of C95 is grounded, the other end of R184 is the inverting input of the A5B comparator, V-Back is the output voltage sampling, V-Back is connected to R179 and C69 to form an RC filter, after filtering, the series resistor R182 is connected to the non-inverting input of the A5B comparator and the cathode of the unidirectional hysteresis diode D6, the anode of D6 is connected to one end of R168, the other end of R168 is connected to the output of the A5B op amp, the output of the A5B op amp is connected to the anode of D13, and the cathode of D13 triggers the hardware shutdown.

2. The fast hardware protection circuit with output overvoltage and overcurrent following setting according to claim 1, characterized in that: include: Iset is the output current reference, connected to R251. R251 and C121 form an RC filter and are connected to the A9B non-inverting input terminal. The A9B inverting input terminal is connected to the op amp output to form a voltage follower. The output current reference is connected to R252 after passing through the voltage follower. R252, R250, R254, R257, and A9A form an adder. R252 is connected to the non-inverting input of A9A and to R250. The other end of R250 is connected to the bias voltage Ibias+, which is used as the output over-current protection threshold setting. After summing with Iset, it is used as the reference point for over-current protection. One end of R254 is grounded, and the other end is connected to the inverting input of A9A. R257 is connected between the inverting input of A9A and the output of the op amp to complete the summation of Iset and Ibias+ as a reference for overcurrent protection. The output of the A9A op amp is connected to R253, and the other end of R253 is connected to C111 and R249. R253 and C111 form an RC filter, the other end of C111 is grounded, the other end of R249 is the inverting input of the A5A comparator, I-Back is the output current sampling, I-Back is connected to R242 and C106 to form an RC filter, after filtering, the series resistor R244 is connected to the non-inverting input of the A5A comparator and the cathode of the unidirectional hysteresis diode D14, the anode of D14 is connected to one end of R240, the other end of R240 is connected to the output of the A5A op amp, the output of the A5A op amp is connected to the anode of D7, and the cathode of D7 triggers the hardware shutdown.

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