Overcurrent protection circuit of airborne computer product

Abstract

The invention provides an over-current protection circuit of an airborne computer product, which belongs to the technical field of airborne computer power supply and distribution management and comprises a power switch and an isolation circuit used for controlling a power supply output switch of a power supply. The current sampling detection circuit is used for establishing a linear relation between the detected current and the output voltage; the signal conditioning circuit is used for conditioning an output signal of the current sampling detection circuit, and when the flowing current is 0A, the output voltage of the signal conditioning circuit is 0V; the comparison circuit is used for comparing the voltage output by the signal conditioning circuit with a preset reference voltage, judging whether overcurrent occurs or not, and outputting an overcurrent signal and closing a power output channel when overcurrent occurs; the level maintaining circuit is used for maintaining the over-current signal and preventing the over-current signal from losing efficacy; after the overcurrent fault is eliminated, the overcurrent protection signal is reset through the overcurrent protection reset signal, and the power output channel is opened again. According to the invention, the safety and reliability of airborne computer products are improved.

Description

Technical Field

[0001] The present application relates to the technical field of power supply and distribution management of airborne computer power supplies, and in particular to an overcurrent protection circuit for airborne computer products. Background Art

[0002] In airborne computer power supply products, it is usually necessary to design an overcurrent protection circuit to meet the airborne computer power supply overcurrent protection requirements, to prevent the aircraft bus from being short-circuited, the fault from spreading, and affecting the operation of other airborne equipment. Traditional overcurrent protection designs usually use fuses, which are irreversible protection measures. When the fault is eliminated, the short-circuit protection cannot be released. In actual applications, the fuse blows slowly, which may cause abnormalities in the onboard power supply bus before the fuse blows, affecting the safety of airborne computer products. Summary of the invention

[0003] In view of this, an embodiment of the present application provides an overcurrent protection circuit for an airborne computer product, which at least partially solves the problem in the prior art that overcurrent protection often uses fuses, which have a slow melting time and may cause abnormalities in the onboard power supply bus before the fuse blows, thereby affecting the safety of the airborne computer product.

[0004] The embodiment of the present application provides an overcurrent protection circuit of an airborne computer product, the circuit comprising a power switch and an isolation circuit, a current sampling detection circuit, a signal conditioning circuit, a comparison circuit and a level maintaining circuit connected in sequence, wherein the output end of the level maintaining circuit is connected to the power switch and the isolation circuit;

[0005] The power switch and the isolation circuit are used to control the power supply output switch;

[0006] The current sampling detection circuit is used to establish a linear relationship between the measured current output by the power switch and the isolation circuit and the output voltage of the current sampling detection circuit;

[0007] The signal conditioning circuit is used to perform signal conditioning on the output voltage signal of the current sampling detection circuit, so that when the flowing current is 0A, the output voltage of the signal conditioning circuit is 0V;

[0008] The comparison circuit is used to compare the voltage output by the signal conditioning circuit with a preset reference voltage to determine whether the measured current is overcurrent, and when overcurrent occurs, output an overcurrent signal to close the power output channel;

[0009] The level maintaining circuit is used to maintain the overcurrent signal to prevent the overcurrent signal from becoming ineffective due to the current being zero after the power output channel is closed; when the overcurrent fault is eliminated, the overcurrent protection signal is reset through the overcurrent protection reset signal to reopen the power output channel.

[0010] According to a specific implementation of the embodiment of the present application, the power switch and the isolation circuit include an isolation diode and a BTS6163D chip connected to each other, and the input V IN Grounded, the driving current is 2.4mA; the switch of the power output channel is controlled by floating or grounding the enable pin level of the BTS6163D chip.

[0011] According to a specific implementation of the embodiment of the present application, the current sampling detection circuit is configured as a Hall current sensor.

[0012] According to a specific implementation of the embodiment of the present application, the model of the Hall current sensor is ACS712ELCTR-20A-T, and the linear relationship between the output voltage of the Hall current sensor and the measured current is:

[0013] V OUT =2.5+I SENSE ×A V ,

[0014] Among them, I SENSE is the measured current flowing through, A V is the proportionality coefficient between current and voltage, V OUT is the output voltage of the Hall current sensor.

[0015] According to a specific implementation method of the embodiment of the present application, the signal conditioning circuit uses an operational amplifier LF147 to form a proportional amplifier, so that the output voltage signal of the current sampling detection circuit is zeroed after operational amplification.

[0016] According to a specific implementation method of the embodiment of the present application, the level maintaining circuit includes an NPN transistor, a PNP transistor, a first NMOS transistor and a second NMOS transistor, the output end of the comparison circuit is respectively connected to the base of the NPN transistor, the emitter of the PNP transistor and the gate of the second NMOS transistor, the emitter of the NPN transistor is grounded, the collector of the NPN transistor is connected to the base of the PNP transistor through a resistor, the collector of the PNP transistor is connected to the power supply VCC through a resistor, the emitter of the PNP transistor is also connected to the source and gate of the first NMOS transistor, the drain of the first NMOS transistor is connected to the PROTECT signal output end, the source of the second NMOS transistor is grounded, the drain of the second NMOS transistor is connected to the base of the NPN transistor, and the gate of the second NMOS transistor is connected to the overcurrent protection reset signal.

[0017] According to a specific implementation of the embodiment of the present application, the comparison circuit includes an operational amplifier LM193.

[0018] Beneficial effects:

[0019] The overcurrent protection circuit of the airborne computer product in the embodiment of the present application provides an overcurrent protection circuit to realize power supply current detection and overcurrent protection. When overcurrent occurs, the overcurrent protection circuit sends an overcurrent protection signal to turn off the power output switch, and the level maintenance circuit maintains the validity of the overcurrent protection signal. When the overcurrent fault is eliminated, the overcurrent protection can be released through the overcurrent reset signal, and the power output switch can be turned on to improve the safety of the airborne computer product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a general block diagram of an overcurrent protection circuit of an onboard computer product according to an embodiment of the present invention;

[0022] Figure 2 A structural diagram of a power switch and an isolation circuit according to an embodiment of the present invention;

[0023] Figure 3 is a structural diagram of a current sampling detection circuit according to an embodiment of the present invention;

[0024] Figure 4 is a structural diagram of a signal conditioning circuit according to an embodiment of the present invention;

[0025] Figure 5 A structural diagram of a comparison circuit and a level maintaining circuit according to an embodiment of the present invention;

[0026] Figure 6 FIG. 4 is a general structural diagram of an overcurrent protection circuit of an onboard computer product according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0028] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0029] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0030] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0031] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0032] Based on the current technical problems, this application hopes to design an overcurrent protection circuit for airborne computer power products through technical research to realize power supply current detection and overcurrent protection. When overcurrent occurs, the overcurrent protection circuit sends an overcurrent protection signal to turn off the power output switch, and the level maintenance circuit maintains the validity of the overcurrent protection signal. When the overcurrent fault is eliminated, the overcurrent protection can be released through the overcurrent reset signal to turn on the power output switch.

[0033] In one embodiment, the present application provides an overcurrent protection circuit for an onboard computer product. Figures 1 to 6Specifically, the circuit includes a power switch and an isolation circuit, a current sampling detection circuit, a signal conditioning circuit, a comparison circuit and a level maintenance circuit connected in sequence, and the output end of the level maintenance circuit is connected to the power switch and the isolation circuit;

[0034] The power switch and the isolation circuit are used to control the power supply output switch;

[0035] The current sampling detection circuit is used to establish a linear relationship between the measured current output by the power switch and the isolation circuit and the output voltage of the current sampling detection circuit;

[0036] The signal conditioning circuit is used to perform signal conditioning on the output voltage signal of the current sampling detection circuit, so that when the flowing current is 0A, the output voltage of the signal conditioning circuit is 0V;

[0037] The comparison circuit is used to compare the voltage output by the signal conditioning circuit with a preset reference voltage to determine whether the measured current is overcurrent, and when overcurrent occurs, output an overcurrent signal to close the power output channel;

[0038] The level maintaining circuit is used to maintain the overcurrent signal to prevent the overcurrent signal from becoming ineffective due to the current being zero after the power output channel is closed; when the overcurrent fault is eliminated, the overcurrent protection signal is reset through the overcurrent protection reset signal to reopen the power output channel.

[0039] In this embodiment, an overcurrent protection circuit is provided to realize power supply current detection and overcurrent protection. When overcurrent occurs, the overcurrent protection circuit sends an overcurrent protection signal to turn off the power output switch, and the level maintenance circuit maintains the validity of the overcurrent protection signal. When the overcurrent fault is eliminated, the overcurrent protection can be released through the overcurrent reset signal, and the power output switch can be turned on, thereby improving the safety of the airborne computer product.

[0040] Specifically, refer to Figure 2 The power switch and isolation circuit include an isolation diode and a BTS6163D chip connected to each other. The input V IN Grounded, the driving current is 2.4mA; the switch of the power output channel is controlled by floating or grounding the enable pin level of the BTS6163D chip. The on / off function of the power switch and the main power output of the isolation circuit is controlled by the BTS6163D.

[0041] In one embodiment, the current sampling detection circuit is configured as a Hall current sensor. The output voltage of the Hall current sensor is "zeroed" after passing through a signal conditioning circuit. According to the characteristics of the Hall current sensor, when the current flowing through is 0, the output is 2V. The signal conditioning circuit is used to condition the output voltage signal of the Hall current sensor, so that when the current flowing through is 0A, the signal conditioning circuit outputs 0V.

[0042] Preferably, the model of the Hall current sensor is ACS712ELCTR-20A-T, and the linear relationship between the output voltage of the Hall current sensor and the measured current is:

[0043] V OUT =2.5+I SENSE ×A V ,

[0044] Among them, I SENSE is the measured current flowing through, A V is the proportionality coefficient between current and voltage, V OUT is the output voltage of the Hall current sensor.

[0045] The 12V voltage output channel current passes through the Hall current sensor and converts the current flowing through it into a voltage signal. The Hall current sensor uses ACS712ELCTR-20A-T. For the specific circuit diagram, refer to Figure 3 .

[0046] In one embodiment, the signal conditioning circuit uses an operational amplifier LF147 to form a proportional amplifier, so that the output voltage signal of the current sampling detection circuit is amplified by the operation to achieve zero adjustment of the output voltage signal.

[0047] Specifically, the current sampling detection circuit has a zero current corresponding to a 2V output voltage. Since the AD sampling voltage range of DSP or MCU is generally 0-3.3V, in order to be compatible with the AD sampling of DSP or MCU and facilitate current calculation, the signal conditioning circuit uses a general-purpose operational amplifier LF147 to form a proportional amplifier to implement the subtraction operation of the current detection signal, so that the output voltage signal of the Hall current sampling circuit is amplified by the operation to achieve "zero adjustment" of the output voltage signal, so that when the current flowing through is 0A, the signal conditioning circuit outputs 0V, as shown in the attached figure. Figure 4 The relationship between the input and output of the signal conditioning circuit is:

[0048] 12V_I_ADJ=12V_I-2.5,

[0049] The Hall current sampling enters the comparison circuit after passing through the signal conditioning circuit.

[0050] In one embodiment, the comparison circuit includes an operational amplifier LM193. After the Hall current sampling passes through the signal conditioning circuit, it is compared with the reference voltage (2V) through the comparator. When the output voltage of the conditioning circuit is greater than 2V, the comparison circuit outputs a high level of 5V, and when it is less than 2V, the comparison circuit outputs a low level of 0V. The output end of the comparison circuit is connected to the input end of the level maintaining circuit.

[0051] In one embodiment, the level maintaining circuit includes an NPN transistor, a PNP transistor, a first NMOS transistor and a second NMOS transistor, the output end of the comparison circuit is respectively connected to the base of the NPN transistor, the emitter of the PNP transistor and the gate of the second NMOS transistor, the emitter of the NPN transistor is grounded, the collector of the NPN transistor is connected to the base of the PNP transistor through a resistor, the collector of the PNP transistor is connected to the power supply VCC through a resistor, the emitter of the PNP transistor is also connected to the source and gate of the first NMOS transistor, the drain of the first NMOS transistor is connected to the PROTECT signal output end, the source of the second NMOS transistor is grounded, the drain of the second NMOS transistor is connected to the base of the NPN transistor, and the gate of the second NMOS transistor is connected to the overcurrent protection reset signal.

[0052] In this embodiment, the characteristics of NPN transistor 2N222 and PNP transistor 2N2907 are used to design a level maintenance circuit to maintain the overcurrent signal to prevent the overcurrent signal from becoming invalid due to the current being zero after the output channel (power switch) is turned off. When the comparison circuit outputs a high level of 5V (overcurrent occurs when the voltage of 12V_I_ADJ is greater than 2V), NPN transistor Q1 (2N222) is turned on, and after NPN transistor Q1 is turned on, it drives PNP transistor Q2 (2N2907) to be turned on. The emitter of PNP transistor Q2 is connected to the base of NPN transistor Q1, which can maintain the stable conduction of NPN transistor Q1, and finally turn on the first NMOS transistor Q4, and the PROTECT signal remains low for a long time, and the PROTECT signal is connected to the control signal output terminal, thereby turning off the power switch.

[0053] Due to the existence of the level maintenance circuit, when the power switch is turned off, the current flowing is 0, the comparison circuit output is 0, and the first NMOS transistor Q4 can still be kept in the on state, so that the PROTECT signal will not be unable to be maintained after the power switch is turned off. When the overcurrent fault is eliminated, the overcurrent protection signal can be reset through the overcurrent protection reset signal (PROTECT_RESET). When PROTECT_RESET is a high level (5V), the first NMOS transistor Q3 is turned on, the base of the NPN transistor Q1 is grounded, and the NPN transistor Q1 is turned off, thereby causing the PNP transistor Q2 to be turned off, and the gate of the first NMOS transistor Q4 is suspended. The first NMOS transistor Q4 is turned off, which eventually causes the PROTECT signal to be suspended and the power output channel to be reopened. The application circuit diagram is as attached Figure 5 .

[0054] The embodiment provided by the present invention realizes power supply current detection and overcurrent protection. When overcurrent occurs, the overcurrent protection circuit sends an overcurrent protection signal to close the power output switch, and the level maintenance circuit maintains the validity of the overcurrent protection signal. When the overcurrent fault is eliminated, the overcurrent protection can be released through the overcurrent reset signal, and the power output switch can be opened, thereby improving the safety and reliability of airborne computer products.

[0055] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An overcurrent protection circuit for an airborne computer product, characterized in that: The circuit comprises a power switch and an isolation circuit, a current sampling detection circuit, a signal conditioning circuit, a comparison circuit and a level maintaining circuit which are connected in sequence, and the output end of the level maintaining circuit is connected to the power switch and the isolation circuit; The power switch and the isolation circuit are used to control the power supply output switch; The current sampling detection circuit is used to establish a linear relationship between the measured current output by the power switch and the isolation circuit and the output voltage of the current sampling detection circuit; The signal conditioning circuit is used to perform signal conditioning on the output voltage signal of the current sampling detection circuit, so that when the flowing current is 0A, the output voltage of the signal conditioning circuit is 0V; The comparison circuit is used to compare the voltage output by the signal conditioning circuit with a preset reference voltage to determine whether the measured current is overcurrent, and when overcurrent occurs, output an overcurrent signal to close the power output channel; The level maintaining circuit is used to maintain the overcurrent signal to prevent the overcurrent signal from becoming ineffective due to the current being zero after the power output channel is closed; when the overcurrent fault is eliminated, the overcurrent protection signal is reset through the overcurrent protection reset signal to reopen the power output channel.

2. The overcurrent protection circuit of the onboard computer product according to claim 1, characterized in that: The power switch and isolation circuit include an isolation diode and a BTS6163D chip connected to each other. The input V IN Grounded, the driving current is 2.4mA; The switch of the power output channel is controlled by floating or grounding the enable pin level of the BTS6163D chip.

3. The overcurrent protection circuit of the onboard computer product according to claim 1, characterized in that: The current sampling detection circuit is configured as a Hall current sensor.

4. The overcurrent protection circuit of the onboard computer product according to claim 3, characterized in that: The model of the Hall current sensor is ACS712ELCTR-20A-T, and the linear relationship between the output voltage of the Hall current sensor and the measured current is: V OUT =2.5+I SENSE ×A V , Among them, I SENSE is the measured current flowing through, A V is the proportionality coefficient between current and voltage, V OUT is the output voltage of the Hall current sensor.

5. The overcurrent protection circuit of the onboard computer product according to claim 1, characterized in that: The signal conditioning circuit uses an operational amplifier LF147 to form a proportional amplifier, so that the output voltage signal of the current sampling detection circuit is amplified by operation to achieve zero adjustment of the output voltage signal.

6. The overcurrent protection circuit of the onboard computer product according to claim 1, characterized in that: The level maintaining circuit includes an NPN transistor, a PNP transistor, a first NMOS transistor and a second NMOS transistor. The output end of the comparison circuit is respectively connected to the base of the NPN transistor, the emitter of the PNP transistor and the gate of the second NMOS transistor. The emitter of the NPN transistor is grounded, the collector of the NPN transistor is connected to the base of the PNP transistor through a resistor, the collector of the PNP transistor is connected to the power supply VCC through a resistor, the emitter of the PNP transistor is also connected to the source and gate of the first NMOS transistor, the drain of the first NMOS transistor is connected to the PROTECT signal output end, the source of the second NMOS transistor is grounded, the drain of the second NMOS transistor is connected to the base of the NPN transistor, and the gate of the second NMOS transistor is connected to the overcurrent protection reset signal.

7. The overcurrent protection circuit of the onboard computer product according to claim 6, characterized in that: The comparison circuit includes an operational amplifier LM193.

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