Disclosure of Invention
The invention mainly aims to provide a short-circuit protection circuit and a short-circuit protection system, and aims to solve the technical problem that the existing short-circuit protection circuit is too high in maintenance cost.
In order to achieve the above object, the present invention provides a short circuit protection circuit, which includes a switch circuit, a control unit and a sampling circuit;
the first input end of the switch circuit is connected with the output end of a load, the second input end of the switch circuit is connected with the output end of the control unit, and the output end of the switch circuit is connected with the input end of the sampling circuit;
the input end of the control unit is connected with the sampling end of the sampling circuit, and the output end of the sampling circuit is connected with the battery;
the sampling circuit is used for sending a high-voltage sampling signal to the control unit when the circuit is short-circuited;
and the control unit is used for controlling the switch circuit to be switched off after receiving the high-voltage sampling signal.
Optionally, the short-circuit protection circuit further comprises a charging protection circuit;
the first input end of the charging protection circuit is connected with a power supply, and the first output end of the charging protection circuit is connected with the input end of the battery;
and a second input end of the charging protection circuit is connected with the output end of the battery, and a second output end of the charging protection circuit is connected with the input end of the load.
Optionally, the charge protection circuit comprises a constant current charging sub-circuit;
the input end of the constant current charging sub-circuit is connected with the power supply, and the output end of the constant current charging sub-circuit is connected with the input end of the battery.
Optionally, the charge protection circuit further comprises a first diode;
the anode of the first diode is connected with the output end of the battery, and the cathode of the first diode is connected with the input end of the load.
Optionally, the switching circuit includes a second diode, an inductor, and a switching tube;
the first end of the inductor is connected with the output end of the load, the second end of the inductor is respectively connected with the anode of the second diode and the first end of the switch tube, and the cathode of the second diode is connected with the cathode of the first diode;
the second end of the switch tube is connected with the output end of the control unit, and the third end of the switch tube is connected with the input end of the sampling circuit.
Optionally, the sampling circuit comprises a differential amplification sub-circuit;
the first end of the differential amplification sub-circuit is connected with the input end of the control unit, and the second end and the third end of the differential amplification sub-circuit are connected with the third end of the switch tube.
Optionally, the sampling circuit further comprises a resistor;
the first end of the resistor is connected with the second end of the differential amplification sub-circuit, and the second end of the resistor is connected with the third end of the differential amplification sub-circuit.
Optionally, the short-circuit protection circuit further comprises a capacitor;
the first end of the capacitor is connected with the cathode of the second diode, and the second end of the capacitor is connected with the first end of the inductor.
Optionally, the switching tube is an N-channel MOS tube.
Further, to achieve the above object, the present invention also provides a short-circuit protection system including a short-circuit protection circuit configured as the short-circuit protection circuit described above.
The invention provides a short-circuit protection circuit and a short-circuit protection system, wherein the short-circuit protection circuit comprises a switch circuit, a control unit and a sampling circuit; the first input end of the switch circuit is connected with the output end of the load, the second input end of the switch circuit is connected with the output end of the control unit, and the output end of the switch circuit is connected with the input end of the sampling circuit; the input end of the control unit is connected with the sampling end of the sampling circuit, and the output end of the sampling circuit is connected with the battery. The sampling circuit is used for sampling input current, converting the sampled current into sampling voltage and outputting the sampling voltage to the control unit, when the circuit is short-circuited and the input current reaches a preset current value, the sampling circuit converts a high current signal obtained by sampling into a high voltage signal and outputs the high voltage signal to the control unit, and the control unit outputs a corresponding PWM signal to control the switch circuit to be switched off, so that the short-circuit is protected. When the short circuit phenomenon appears in the circuit, only need control switch circuit to turn off can play the guard action, need not to change internal components and parts, the effectual maintenance cost who reduces the circuit.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a short-circuit protection circuit according to an embodiment of the present invention, where the short-circuit protection circuit includes a switch circuit 10, a control unit 20, and a sampling circuit 30; a first input end of the switch circuit 10 is connected with an output end of the load, a second input end of the switch circuit 10 is connected with an output end of the control unit 20, and an output end of the switch circuit 10 is connected with an input end of the sampling circuit 30; the input end of the control unit 20 is connected to the sampling end of the sampling circuit 30, and the output end of the sampling circuit 30 is connected to the battery.
The control unit 20 in this embodiment is preferably a PWM control chip, and the switching circuit 10 is turned on or off by sending PWM signals with different duty ratios to the switching circuit 10; the switch circuit 10 in the present embodiment is preferably a BUCK circuit, which is a kind of BUCK conversion circuit; the sampling circuit 30 in this embodiment is configured to sample an input current to obtain a sampling current, convert the sampling current into a sampling voltage signal, and output the sampling voltage signal to the control unit 20, so that the control unit 20 outputs a corresponding PWM signal according to the sampling voltage signal, thereby achieving the purpose of controlling the switching circuit 10 to be turned on or off.
When the load normally works, the sampling current obtained by sampling by the sampling circuit 30 is converted into sampling voltage and is sent to the control unit 20, the control unit 20 outputs a PWM signal with a duty ratio close to 100% to the switch circuit 10, the switch circuit 10 is controlled to be turned on, and meanwhile, the load in the embodiment is also connected with a power supply (not shown in the figure), and a complete discharge loop is formed by turning on the switch circuit 10.
When the load is short-circuited or heavy-loaded, the sampling circuit 30 samples to obtain a sampling current with a higher current value, as an implementation manner, the current value 10A may be preset, that is, when the sampling circuit 30 is higher than 10A, it is determined that the load is short-circuited or heavy-loaded at this time, the sampling circuit 30 converts a high current signal into a high voltage signal and sends the high voltage signal to the control unit 20, and the control unit 20 adjusts the duty ratio of the output PWM signal accordingly, and limits the duty ratio of the PWM signal within a safe range, thereby implementing periodic peak current control.
The sampling circuit 30 in this embodiment is configured to sample an input current, convert the sampled current into a sampling voltage, and output the sampling voltage to the control unit 20, when a short circuit occurs in the circuit and the input current reaches a preset current value, the sampling circuit 30 converts a sampled high current signal into a high voltage signal and outputs the high voltage signal to the control unit 20, and the control unit 20 outputs a corresponding PWM signal to control the switching circuit 10 to turn off, thereby protecting the short circuit. When the short circuit phenomenon appears in the circuit, only need control switch circuit 10 to turn off can play the guard action, need not to change internal components and parts, the effectual maintenance cost who reduces the circuit.
Further, referring to fig. 2, fig. 2 is a schematic structural diagram of another embodiment of the short-circuit protection circuit of the present invention. The short-circuit protection circuit further includes a charge protection circuit 40; a first input end of the charging protection circuit 40 is connected with a power supply, and a first output end of the charging protection circuit 40 is connected with an input end of a battery; a second input terminal of the charging protection circuit 40 is connected to the output terminal of the battery, and a second output terminal of the charging protection circuit 40 is connected to the input terminal of the load.
Further, the charge protection circuit 40 includes a constant current charge circuit 41; the input end of the constant current charging sub-circuit 41 is connected with a power supply, and the output end of the constant current charging sub-circuit 41 is connected with the input end of the battery.
Further, the charge protection circuit 40 further includes a first diode D1; the anode of the first diode D1 is connected to the output terminal of the battery, and the cathode of the first diode D1 is connected to the input terminal of the load.
A charge protection circuit 40 is further provided in the present embodiment, wherein the charge protection circuit 40 includes a constant-range charge sub-circuit and a first diode D1. As shown in fig. 2, the input terminal of the constant current charging sub-circuit 41 is connected to a power supply, and the output terminal of the constant current charging sub-circuit 41 is connected to the battery, so that the power supply can stably charge the battery through the constant current charging sub-circuit 41. Meanwhile, a first diode D1 is connected with the battery, the anode of the first diode D1 is connected with the output end of the battery, and the cathode of the first diode D1 is connected with the input end of the load, so that the unidirectional circulation of the output current of the battery is ensured.
The constant current charging electronic circuit 41 is arranged in the embodiment to ensure that the power supply stably supplies power to the battery and ensure the safety of the battery in the charging process; the first diode D1 is provided to ensure unidirectional output current of the battery and protect the battery during the output process of the battery. That is, the present embodiment plays a role of protecting the safety of the battery during the charging and discharging processes by providing the charge protection circuit 40.
Further, with reference to fig. 2, the switch circuit 10 includes a second diode D2, an inductor L1, and a switch Q1; a first end of the inductor L1 is connected to an output end of the load, a second end of the inductor L1 is connected to an anode of the second diode D2 and a first end of the switching tube Q1, respectively, and a cathode of the second diode D2 is connected to a cathode of the first diode D1; the second terminal of the switch Q1 is connected to the output terminal of the control unit 20, and the third terminal of the switch Q1 is connected to the input terminal of the sampling circuit 30.
In the embodiment, a second diode D2, an inductor L1 and a switching tube Q1 are arranged to jointly form a common positive BUCK circuit, in the common positive BUCK circuit, when the switching tube Q1 is driven to be at a high level, the switching tube Q1 is turned on, the inductor L1 is magnetized, and the current flowing through the inductor L1 is increased linearly; when the switch Q1 is driven low, the switch Q1 turns off, the inductor L1 discharges through the second diode D2, and the inductor L1 current decreases linearly. The switching tube Q1 may be an N-channel MOS tube, a gate of the MOS tube is connected to the control unit 20, a source of the MOS tube is connected to the sampling circuit 30, and a drain of the MOS tube is connected to the second end of the inductor L1.
In the present embodiment, the second diode D2, the inductor L1, and the switching tube Q1 are provided, and the entire components are configured as a common positive BUCK circuit, and the input of the load is adjusted when the load is short-circuited by using the characteristics of the BUCK circuit, thereby performing a short-circuit protection function.
Further, the sampling circuit 30 includes a differential amplification sub-circuit 31; a first terminal of the differential amplifier sub-circuit 31 is connected to the input terminal of the control unit 20, and a second terminal and a third terminal of the differential amplifier sub-circuit 31 are connected to a third terminal of the switch Q1.
Further, the sampling circuit 30 further includes a resistor R1; the first end of the resistor R1 is connected to the second end of the differential amplifier sub-circuit 31, and the second end of the resistor R1 is connected to the third end of the differential amplifier sub-circuit 31.
Further, the short-circuit protection circuit further comprises a capacitor C1; a first terminal of the capacitor C1 is connected to the cathode of the second diode D2, and a second terminal of the capacitor C1 is connected to a first terminal of the inductor L1.
The sampling circuit 30 in this embodiment includes a differential amplification sub-circuit 31 and a resistor R1, it is easily understood that the resistor R1 is used as the sampling resistor R1, as a preferred mode, the differential amplification sub-circuit 31 includes an operational amplifier, the differential amplification sub-circuit 31 converts the current of the sampling resistor R1 into a sampling voltage and transmits the sampling voltage to the control unit 20, and the control unit 20 determines whether the load is short-circuited according to the obtained value of the sampling voltage. In addition, in the present embodiment, a capacitor C1 functioning as a filter is also provided. It is easy to understand that when the load is short-circuited, the current on the resistor R1 increases, the corresponding sampling voltage output by the differential amplifier sub-circuit 31 also increases, and when the current exceeds a certain value, the control unit 20 adjusts the duty ratio of the output PWM signal to realize protection of the load.
Further, the present invention also protects a short-circuit protection system, which includes a short-circuit protection circuit, and the structure of the short-circuit protection circuit can refer to the above embodiments, and is not described herein again. It should be noted that, since the short-circuit protection system of the present embodiment adopts the technical solution of the short-circuit protection circuit, the short-circuit protection system has all the beneficial effects of the short-circuit protection circuit.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.