CN110658882B - Switch control circuit, control method and central control box applying same - Google Patents

Switch control circuit, control method and central control box applying same Download PDF

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Publication number
CN110658882B
CN110658882B CN201910945411.0A CN201910945411A CN110658882B CN 110658882 B CN110658882 B CN 110658882B CN 201910945411 A CN201910945411 A CN 201910945411A CN 110658882 B CN110658882 B CN 110658882B
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electrically connected
load
switch control
control circuit
operational amplifier
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CN110658882A (en
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蒋永玉
李功杰
蒋龙
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Yangzhou Dongbo Electronic Technology Co ltd
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Yangzhou Dongbo Electronic Technology Co ltd
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/625—Regulating voltage or current wherein it is irrelevant whether the variable actually regulated is ac or dc
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
    • H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Electronic Switches (AREA)

Abstract

The invention discloses a switch control circuit, a control method and a central control box applying the circuit, belongs to the technical field of central electric appliance control, and solves the problems of high working current, low safety, easy ignition and damage, low integration level and large occupied space of the traditional central control box. The power supply mainly comprises an input power supply, a load signal input end, an MOS tube switch control circuit module, a load and the like. The circuit has the advantages of simple design, high stability, small working current, weak current environment, high safety performance, low power consumption, environmental protection and energy conservation; the phenomenon of arc striking is avoided, and the service life of the product is long; the occupied space is small, portable and small; the invention changes the design thinking of the traditional central control box and has extremely important significance in the technical field of central electric appliance control.

Description

Switch control circuit, control method and central control box applying same
Technical Field
The invention belongs to the technical field of central electric appliance control, and particularly relates to a switch control circuit, a control method and a central control box using the circuit, wherein the switch control circuit has the advantages of small working current, high safety, low power consumption, environmental protection, energy conservation, no sparking phenomenon and long service life of a product.
Background
The central control box is widely applied to electrical appliances such as tractors, automobiles and the like, and mainly has the functions of reducing the number of loop linear speeds and carrying out centralized control on the electrical appliances. The conventional central control box electric part mainly includes a relay switch circuit, a flasher circuit, a fuse, and the like. That is, the traditional central control box utilizes a relay switch circuit to realize the switching function of electric equipment and utilizes a fuse to realize the overload protection function. However, the central control box has the following disadvantages: 1. the relay circuit design has large working current, and the phenomenon of arc ignition is easy to generate in the attracting process, so that on one hand, the safety performance is poor, and on the other hand, the service life of the product is seriously influenced; 2. a plurality of relays are arranged on one central control box, so that the occupied space is large, and the integration and miniaturization of a circuit board are not facilitated.
Disclosure of Invention
The invention aims to provide a switch control circuit, a control method and a central control box applying the circuit, wherein the switch control circuit has the advantages of small working current, high safety, low power consumption, environmental protection, energy conservation, no sparking phenomenon and long service life of products, and aims to overcome the defects of the prior art.
The invention is realized by the following technical scheme:
a switch control circuit comprises an input power supply, a load signal input end, an MOS tube switch control circuit module and a load; the input power supply provides a working power supply for the MOS tube switch control circuit module; the output end of the MOS tube switch control circuit module is electrically connected with the load, and the MOS tube switch control circuit module controls the on and off of a load loop according to an input signal of the load signal input end.
Preferably, the MOS transistor switch control circuit module includes a load signal input terminal, an NMOS transistor, a PMOS transistor, and a sub-switch circuit; the load signal input end is electrically connected with the PMOS tube through a sub-switch circuit, and the sub-switch circuit controls the PMOS tube to be switched on and off; the PMOS tube is electrically connected with the NMOS tube and is used for controlling the connection and disconnection of the NMOS tube; the input power supply, the NMOS tube and the load form the load loop, and the on and off of the NMOS tube determine the on and off of the load loop.
Preferably, the sub-switch circuit comprises a transistor Q13, and the b pole of the transistor Q13 is electrically connected with the load signal input end through a resistor R51; the e pole of the triode Q13 is grounded; the c electrode of the triode Q13 is electrically connected with the G electrode of the PMOS tube and one end of the resistor R47 through the resistor R49, the other end of the resistor R47 is electrically connected with the S electrode of the PMOS tube, and the S electrode of the PMOS tube is also electrically connected with a power supply end; the D electrode of the PMOS tube is electrically connected with one end of a resistor R44, and the other end of the resistor R44 is grounded and is electrically connected with the G end of the NMOS tube; the NMOS tube S end is connected with the load 4, and the NMOS tube S end and the end G are electrically connected with a voltage regulator tube D9; and the end D of the NMOS tube is electrically connected with the input power supply 1.
Preferably, a capacitor C10 for filtering is electrically connected between the resistor R44 and the ground, and a resistor R46 for voltage division is connected in parallel across the capacitor C10.
Preferably, the switch control circuit further comprises a main control module, wherein the main control module comprises a state tracking circuit unit and a protection execution circuit unit; the state tracking circuit unit collects sampling voltage on the MOS tube switch control circuit module, the input end of the state tracking circuit unit is electrically connected with the MOS tube switch control circuit module, the output end of the state tracking circuit unit is electrically connected with the protection execution circuit unit, the MOS tube switch control circuit module is switched off by the protection execution circuit unit, and the MOS tube switch control circuit module is controlled to be in a state of keeping switching off.
Preferably, the state tracking circuit unit takes a general operational amplifier as a core, and the protection execution circuit unit takes a logic and gate as a core; the positive end and the negative end of the general operational amplifier respectively collect the voltage at two ends of a sampling resistor on the MOS tube switch control circuit module; the output end of the general operational amplifier is electrically connected with one input end of the logic AND gate, and the other input end of the logic AND gate is electrically connected with the load signal input end; the output end of the logic AND gate is electrically connected with the MOS tube switch control circuit module to control the turn-off of the MOS tube switch control circuit module; the output end of the logic AND gate also feeds back an electric signal to the state tracking circuit unit through a feedback circuit, and the MOS tube switch control circuit module is kept in a turn-off state all the time through the state tracking circuit unit and the protection execution circuit unit.
Preferably, the switch control circuit further includes an alarm unit controlled by the protection execution circuit unit.
Preferably, the alarm unit comprises an alarm sub-switch circuit and a light emitting diode, and the alarm sub-switch circuit is electrically connected with the output end of the logic and gate.
A method for controlling the switch control circuit, the method comprising:
the load signal input end inputs an effective level, the sub-switch circuit is conducted, the PMOS tube is conducted due to the fact that the conduction condition is met, the NMOS tube is conducted due to the fact that the conduction condition is met after the PMOS tube is conducted, the NMOS tube is conducted, the load circuit is conducted, and the load normally does work;
the load circuit is electrically connected with a sampling resistor, and the positive input end and the negative input end of the general operational amplifier respectively collect the voltages at the two ends of the sampling resistor; judging according to the acquired voltage value, wherein the voltage value acquired by the negative end of the general operational amplifier is larger than the voltage value acquired by the positive end of the general operational amplifier, and the output end of the general operational amplifier outputs an invalid level; the logic AND gate electrically connected with the output end of the general operational amplifier is in a turn-off state because the logic AND gate does not meet the turn-on condition; at the moment, the load on the load loop is in a normal acting state;
when the overload condition appears in the load circuit because of the fault, the voltage at the two ends of the sampling resistor is abnormal, the voltage value collected by the negative end of the general operational amplifier is smaller than the voltage value collected by the positive end of the general operational amplifier, and at the moment, the effective level is output by the output end of the general operational amplifier. One input end of the logic AND gate is electrically connected with the output end of the general operational amplifier and is in an effective level, the other input end of the logic AND gate is electrically connected with the load signal input end and is also in an effective level, and the logic AND gate outputs the effective level at the moment; the effective level output by the logic AND gate turns off the sub-switch circuit, the PMOS tube is turned off because the PMOS tube does not meet the conduction condition, the NMOS tube is turned off because the PMOS tube does not meet the conduction condition after being turned off, and the NMOS tube is turned off to turn off the load loop; meanwhile, the effective level output by the logic AND gate is also fed back to the negative terminal of the general operational amplifier, so that the voltage value of the negative terminal of the general operational amplifier is kept in a state of being smaller than the voltage value of the positive terminal of the general operational amplifier, and the output end of the general operational amplifier keeps outputting the effective level, thereby keeping the load loop in a turn-off state.
A central control box is internally applied with the switch control circuit.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention skillfully utilizes the MOS tube to realize the on-off of the load loop, and has the advantages of simple and non-redundant circuit design, high circuit stability, small working current, weak current environment, high safety performance, low power consumption, environmental protection and energy conservation; the phenomenon of arc striking is avoided, and the service life of the product is long;
2. the electronic device has small volume, high integration degree and small occupied space, and meets the miniaturization requirement of the central control box;
3. the invention has powerful functions, monitors the loop state in real time in the process of load doing work, automatically cuts off the loop if the overload is abnormal, and keeps the loop in the cut-off state before maintenance; the circuit for realizing the function is ingenious and concise in design, and the function of the product is realized and the stability of the circuit is ensured by using the least components;
4. the invention also has the alarm function, which side has a fault is clear at a glance, and the alarm circuit can be realized by a small number of components;
5. the invention has less integral components and parts, has no special requirements on the model, is a common chip in the market, and effectively controls the production cost;
6. the invention changes the design thinking of the traditional central control box and has extremely important significance in the technical field of central electric appliance control.
Drawings
FIG. 1 is a system block diagram of embodiment 1 of the present invention;
FIG. 2 is a schematic circuit diagram of embodiment 1 of the present invention;
FIG. 3 is a schematic circuit diagram according to embodiment 2 of the present invention;
FIG. 4 is a system block diagram of embodiment 3 of the present invention;
FIG. 5 is a first schematic circuit diagram according to embodiment 3 of the present invention;
FIG. 6 is a second schematic circuit diagram according to embodiment 3 of the present invention;
FIG. 7 is a first schematic circuit diagram according to embodiment 4 of the present invention;
fig. 8 is a second schematic circuit diagram according to embodiment 4 of the present invention.
In the figure: 1. inputting a power supply; 2. a load signal input; 3, an MOS tube switch control circuit module; 4. a load; 5. a main control module; 6. a state tracking circuit unit; 7. and protecting the execution circuit unit.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
a switch control circuit comprises an input power supply 1, a load signal input end 2, an MOS tube switch control circuit module 3 and a load 4; the input power supply 1 provides a working power supply for the MOS tube switch control circuit module 3; the output end of the MOS tube switch control circuit module 3 is electrically connected with the load 4, and the conduction and the disconnection of a load loop are controlled according to the input signal of the load signal input end 2.
Preferably, the MOS transistor switch control circuit module 3 includes a load signal input terminal 2, an NMOS transistor, a PMOS transistor, and a sub-switch circuit; the load signal input end 2 is electrically connected with the PMOS tube through a sub-switch circuit, and the sub-switch circuit controls the PMOS tube to be switched on and off; the PMOS tube is electrically connected with the NMOS tube and is used for controlling the connection and disconnection of the NMOS tube; the input power supply 1, the NMOS tube and the load 4 form the load loop, and the on and off of the NMOS tube determine the on and off of the load loop. The MOS tube is skillfully utilized to realize the on-off of a load loop, the circuit design is simple and not long, the circuit stability is high, the working current is small, the weak current environment is high, the safety performance is high, the power consumption is low, and the environment is protected and energy is saved; the phenomenon of arc striking is not worried, and the service life of the product is long.
Preferably, the sub-switch circuit comprises a transistor Q13, and the b pole of the transistor Q13 is electrically connected with the load signal input terminal 2 through a resistor R51; the e pole of the triode Q13 is grounded; the c electrode of the triode Q13 is electrically connected with the G electrode of the PMOS tube and one end of the resistor R47 through the resistor R49, the other end of the resistor R47 is electrically connected with the S electrode of the PMOS tube, and the S electrode of the PMOS tube is also electrically connected with a power supply end; the D electrode of the PMOS tube is electrically connected with one end of a resistor R44, and the other end of the resistor R44 is grounded and is electrically connected with the G end of the NMOS tube; the NMOS tube S end is connected with the load 4, and the NMOS tube S end and the end G are electrically connected with a voltage regulator tube D9; and the end D of the NMOS tube is electrically connected with the input power supply 1. The circuit design is simple and not long, the circuit stability is high, the environment is protected, the energy is saved, the size of the related electronic device is small, the integration degree is high, the occupied space is small, and the miniaturization requirement of the central control box is met.
Preferably, a capacitor C10 for filtering is electrically connected between the resistor R44 and the ground, and a resistor R46 for voltage division is connected in parallel across the capacitor C10. The circuit design can improve the circuit precision and the stability of the circuit, and the capacitor C10 has a filtering effect. The voltage difference between the NMOS tubes G and S is ensured not to exceed 12V through the voltage division of R46 and R44, and the conduction NMOS tube is ensured to meet the conduction condition under the effective level.
Preferably, the switch control circuit further includes a main control module 5, and the main control module 5 includes a state tracking circuit unit 6 and a protection execution circuit unit 7; the state tracking circuit unit 6 collects sampling voltage on the MOS transistor switch control circuit module 3, an input end of the state tracking circuit unit is electrically connected with the MOS transistor switch control circuit module 3, an output end of the state tracking circuit unit is electrically connected with the protection execution circuit unit 7, the MOS transistor switch control circuit module 3 is turned off by the protection execution circuit unit 7, and the MOS transistor switch control circuit module 3 is controlled to be in a state of keeping being turned off. On the basis of the basic switch function, the main control module is designed to realize the overload protection function of the whole circuit. The function is powerful, the loop state is monitored in real time in the process of acting by a load, if the overload is abnormal, the loop is automatically cut off, and the loop is kept in the cut-off state before maintenance; the circuit is ingenious and concise in design, and the functions of the product are realized and the stability of the circuit is ensured by using the least components.
Preferably, the state tracking circuit unit 6 takes a general operational amplifier U1B as a core, and the protection execution circuit unit 7 takes a logic and gate as a core; the positive end and the negative end of the universal operational amplifier U1B respectively collect voltages at two ends of a sampling resistor on the MOS transistor switch control circuit module 3; the output end of the general operational amplifier U1B is electrically connected with one input end of a logic AND gate, and the other input end of the logic AND gate is electrically connected with the load signal input end 2; the output end of the logic AND gate is electrically connected with the MOS tube switch control circuit module 3 to control the turn-off of the MOS tube switch control circuit module 3; the output end of the logic and gate also feeds back an electric signal to the state tracking circuit unit 6 through a feedback circuit, and the MOS transistor switch control circuit module 3 is kept in a turn-off state all the time through the state tracking circuit unit 6 and the protection execution circuit unit 7. The universal operational amplifier U1B and the logic AND gate are used as core chips, the whole circuit is ingenious and simple in design, and the functions of the product and the stability of the circuit are guaranteed by the least components; the types of components are not required to a large extent, and the universal operational amplifier U1B and a common logic AND gate circuit are only required; therefore, the circuit design of the application also has the advantages of low cost and easy production.
Preferably, the switch control circuit further comprises an alarm unit controlled by the protection execution circuit unit 7. The invention also has the alarm function, which side has a fault is clear at a glance, and the alarm circuit can be realized by only using a small number of components, so the cost is low;
preferably, the alarm unit comprises an alarm sub-switch circuit and a light emitting diode, and the alarm sub-switch circuit is electrically connected with the output end of the logic and gate.
A method for controlling the switch control circuit, the method comprising:
the load signal input end 2 inputs an effective level, the sub-switch circuit is conducted, the PMOS tube is conducted due to the fact that the conduction condition is met, the NMOS tube is conducted due to the fact that the conduction condition is met after the PMOS tube is conducted, the NMOS tube is conducted to enable a load loop to be conducted, and the load 4 normally does work;
the load circuit is electrically connected with a sampling resistor, and the positive input end and the negative input end of the universal operational amplifier U1B respectively collect the voltages at the two ends of the sampling resistor; judging according to the acquired voltage value, wherein the voltage value acquired by the negative end of the universal operational amplifier U1B is larger than the voltage value acquired by the positive end of the universal operational amplifier U1B, and the output end of the universal operational amplifier U1B outputs an invalid level; the logic AND gate electrically connected with the output end of the general operational amplifier U1B is in an OFF state because the logic AND gate does not meet the opening condition; at this time, the load 4 on the load loop is in a normal acting state;
when the overload condition appears in the load circuit because of the fault, the voltage at the two ends of the sampling resistor is abnormal, the voltage value collected by the negative end of the universal operational amplifier U1B is smaller than the voltage value collected by the positive end of the universal operational amplifier U1B, and at the moment, the effective level is output by the output end of the universal operational amplifier U1B. One input end of the logic AND gate is electrically connected with the output end of the general operational amplifier U1B and is at an effective level, the other input end of the logic AND gate is electrically connected with the load signal input end 2 and is also at an effective level, and the logic AND gate outputs the effective level at the moment; the effective level output by the logic AND gate turns off the sub-switch circuit, the PMOS tube is turned off because the PMOS tube does not meet the conduction condition, the NMOS tube is turned off because the PMOS tube does not meet the conduction condition after being turned off, and the NMOS tube is turned off to turn off the load loop; meanwhile, the effective level output by the logic AND gate is also fed back to the negative terminal of the general operational amplifier U1B, so that the voltage value of the negative terminal of the general operational amplifier U1B is kept to be smaller than the voltage value of the positive terminal of the general operational amplifier U1B, the output end of the general operational amplifier U1B is kept to output the effective level, and a load loop is kept to be in a turn-off state.
The circuit control method is novel, the load loop is monitored in real time by using the sampling resistor, the universal operational amplifier U1B and the logic AND gate, the load loop can be cut off when abnormality is detected, and the loop is kept in a cut-off state before maintenance.
A central control box is internally applied with the switch control circuit. The electronic device related to the switch control circuit of the application has the advantages of small volume, high integration degree and small occupied space, and the miniaturization requirement of the central control box is met; and the components are common components in the market, so that the cost of the central control box is effectively controlled.
Example 1:
as shown in fig. 1 and fig. 2 of the attached drawings of the specification, the present embodiment includes an input power supply 1, a load signal input terminal 2, a MOS transistor switch control circuit module 3, and a load 4; the input power supply 1 provides a working power supply for the MOS tube switch control circuit module 3; the MOS tube switch control circuit module 3 comprises a load signal input end 2, an NMOS tube, a PMOS tube and a sub-switch circuit; the load signal input end 2 is electrically connected with the PMOS tube through a sub-switch circuit, and the sub-switch circuit controls the PMOS tube to be switched on and off; the PMOS tube is electrically connected with the NMOS tube and is used for controlling the connection and disconnection of the NMOS tube; the input power supply 1, the NMOS tube and the load 4 form a load loop, and the on and off of the NMOS tube determine the on and off of the load loop; the output end of the MOS tube switch control circuit module 3 is electrically connected with a load 4, and the load circuit is controlled to be switched on and off according to the input signal of the load signal input end 2.
Further, the input power source 1 is powered by an appliance level, such as a tractor power level. The sub-switch circuit comprises a resistor R51, a resistor R49 and a transistor Q13. The load loop comprises an input power supply 1, an NMOS tube and a load, and the on and off of the NMOS tube determines whether the load does work. The load refers to electric equipment on the electric appliance, such as a high beam, a regulator, an instrument power supply, a wiper and the like.
The specific connection relationship of the circuit of this embodiment is: the b pole of the triode Q13 is electrically connected with the load signal input end 2 through a resistor R51; the e pole of the triode Q13 is grounded; the c electrode of the triode Q13 is electrically connected with the G electrode of the PMOS tube and one end of the resistor R47 through the resistor R49, the other end of the resistor R47 is electrically connected with the S electrode of the PMOS tube, and the S electrode of the PMOS tube is also electrically connected with a power supply end; the D electrode of the PMOS tube is electrically connected with one end of a resistor R44, and the other end of the resistor R44 is grounded and is electrically connected with the G end of the NMOS tube; the end S of the NMOS tube is connected with the load 4, and the end S of the NMOS tube and the end G of the NMOS tube are electrically connected with a voltage regulator tube D9; the end D of the NMOS tube is electrically connected with an input power supply 1.
The working principle of the circuit is as follows: when the load is needed to do work, the effective level is input at the signal input end, for the convenience of expression, the triode Q13 adopts an NPN type triode, namely the effective level is the high level. The signal input end inputs high level, the triode Q13 is conducted, conducting voltage is generated at the two ends S and G of the PMOS tube, the PMOS tube is conducted, the voltage of the power supply end is transmitted to the NMOS tube, the two ends G and S of the NMOS tube generate conducting voltage, the NMOS tube is conducted, the load loop is conducted, and the load is electrified to do work; the voltage regulator tube D9 stabilizes the voltage at 12V, making the NMOS tube work stably.
The embodiment skillfully utilizes the MOS tube to realize the on-off of the load loop, and has the advantages of simple and non-redundant circuit design, high circuit stability, small working current, weak current environment, high safety performance, low power consumption, environmental protection and energy conservation; the phenomenon of arc striking is avoided, and the service life of the product is long; the circuit design is simple and not long, the circuit stability is high, the environment is protected, the energy is saved, the size of the related electronic device is small, the integration degree is high, the occupied space is small, and the miniaturization requirement of the central control box is met.
Example 2:
as shown in fig. 3 of the drawings attached to the specification, in this embodiment, a capacitor C10 functioning as a filter is electrically connected between the resistor R44 and the ground in addition to embodiment 1, and a resistor R46 functioning as a voltage divider is connected in parallel to both ends of the capacitor C10. The circuit design can improve the circuit precision and the stability of the circuit, and the capacitor C10 has a filtering effect. The voltage difference between the NMOS tubes G and S is ensured not to exceed 12V through the voltage division of R46 and R44, and the smooth conduction of the conduction NMOS tube under the effective level is ensured.
Example 3:
as shown in fig. 4 to fig. 6 of the accompanying drawings of the specification, this embodiment further includes a main control module 5 on the basis of the embodiments 1 and 2, where the main control module 5 includes a state tracking circuit unit 6 and a protection execution circuit unit 7; the state tracking circuit unit 6 collects sampling voltage on the MOS tube switch control circuit module 3, the input end of the state tracking circuit unit is electrically connected with the MOS tube switch control circuit module 3, the output end of the state tracking circuit unit is electrically connected with the protection execution circuit unit 7, the MOS tube switch control circuit module 3 is switched off by the protection execution circuit unit 7, and the MOS tube switch control circuit module 3 is controlled to be in a state of keeping switching off. On the basis of the basic switch function, the main control module is designed to realize the overload protection function of the whole circuit. The function is powerful, the loop state is monitored in real time in the process of acting by a load, if the overload is abnormal, the loop is automatically cut off, and the loop is kept in the cut-off state before maintenance; the circuit is ingenious and concise in design, and the functions of the product are realized and the stability of the circuit is ensured by using the least components.
The state tracking circuit unit 6 takes a universal operational amplifier U1B as a core, and the protection execution circuit unit 7 takes a logic AND gate as a core; the positive end and the negative end of the universal operational amplifier U1B respectively collect the voltage at two ends of a sampling resistor on the MOS transistor switch control circuit module 3; the output end of the general operational amplifier U1B is electrically connected with one input end of the logic AND gate, and the other input end of the logic AND gate is electrically connected with the load signal input end 2; the output end of the logic AND gate is electrically connected with the MOS tube switch control circuit module 3 to control the turn-off of the MOS tube switch control circuit module 3; the output end of the logic and gate also feeds back the electric signal to the state tracking circuit unit 6 through a feedback circuit, and the MOS tube switch control circuit module 3 is kept in a turn-off state all the time through the state tracking circuit unit 6 and the protection execution circuit unit 7. The universal operational amplifier U1B and the logic AND gate are used as core chips, the whole circuit is ingenious and simple in design, and the functions of the product and the stability of the circuit are guaranteed by the least components; the types of components are not required to a large extent, and the universal operational amplifier U1B and a common logic AND gate circuit are only required; therefore, the circuit design of the application also has the advantages of low cost and easy production.
The load signal input end 2 inputs an effective level, the sub-switch circuit is conducted, the PMOS tube is conducted due to the fact that the conduction condition is met, the NMOS tube is conducted due to the fact that the conduction condition is met after the PMOS tube is conducted, the NMOS tube is conducted to enable a load loop to be conducted, and the load 4 normally does work;
the load circuit is electrically connected with a sampling resistor, and the positive input end and the negative input end of the universal operational amplifier U1B respectively collect voltages at two ends of the sampling resistor; judging according to the acquired voltage value, wherein the voltage value acquired by the negative end of the universal operational amplifier U1B is larger than the voltage value acquired by the positive end of the universal operational amplifier U1B, and the output end of the universal operational amplifier U1B outputs an invalid level; the logic AND gate electrically connected with the output end of the general operational amplifier U1B is in an OFF state because the logic AND gate does not meet the opening condition; at this time, the load 4 on the load loop is in a normal acting state;
when the overload condition appears in the load circuit because of the fault, the voltage at the two ends of the sampling resistor is abnormal, the voltage value collected by the negative end of the universal operational amplifier U1B is smaller than the voltage value collected by the positive end of the universal operational amplifier U1B, and at the moment, the effective level is output by the output end of the universal operational amplifier U1B. One input end of the logic AND gate is electrically connected with the output end of the general operational amplifier U1B and is at an effective level, the other input end of the logic AND gate is electrically connected with the load signal input end 2 and is also at an effective level, and the logic AND gate outputs the effective level at the moment; the effective level output by the logic AND gate turns off the sub-switch circuit, the PMOS tube is turned off because the PMOS tube does not meet the conduction condition, the NMOS tube is turned off because the PMOS tube does not meet the conduction condition after being turned off, and the NMOS tube is turned off to turn off the load loop; meanwhile, the effective level output by the logic AND gate is also fed back to the negative terminal of the general operational amplifier U1B, so that the voltage value of the negative terminal of the general operational amplifier U1B is kept to be smaller than the voltage value of the positive terminal of the general operational amplifier U1B, the output end of the general operational amplifier U1B is kept to output the effective level, and a load loop is kept to be in a turn-off state. The circuit control method is novel, the load loop is monitored in real time by using the sampling resistor, the universal operational amplifier U1B and the logic AND gate, the load loop can be cut off when abnormality is detected, and the loop is kept in a cut-off state before maintenance.
The specific circuit connection relationship of this embodiment is: the b pole of the triode Q13 is electrically connected with the load signal input end 2 through a resistor R51; the e pole of the triode Q13 is grounded; the c electrode of the triode Q13 is electrically connected with the G electrode of the PMOS tube and one end of the resistor R47 through the resistor R49, the other end of the resistor R47 is electrically connected with the S electrode of the PMOS tube, and the S electrode of the PMOS tube is also electrically connected with a power supply end; the D electrode of the PMOS tube is electrically connected with one end of a resistor R44, and the other end of the resistor R44 is grounded and is electrically connected with the G end of the NMOS tube; the end S of the NMOS tube is connected with the load 4, and the end S of the NMOS tube and the end G of the NMOS tube are electrically connected with a voltage regulator tube D9; the D end of the NMOS tube is electrically connected with the input power supply 1 through a sampling resistor R27. The general operational amplifier U1B, the resistor R34, the resistor R35, the sampling resistor R27, the resistor R31 and the resistor R39 form a state tracking circuit unit 6; the positive input end of the general operational amplifier U1B is electrically connected with one end of the sampling resistor R27 through a resistor R34 and a resistor R35, and the positive input end is grounded through a resistor R31; the negative input end of the general operational amplifier U1B is electrically connected with the other end of the sampling resistor R27 through a resistor R39, and the negative input end is grounded through a resistor R42; the output end of the general operational amplifier U1B is electrically connected with the input end of the 1 pin of the logic AND gate through a resistor R35, and the input end of the 2 pin of the logic AND gate is electrically connected with the input end 2 of the load signal through a resistor R50; a voltage regulator tube D10, a voltage regulator tube D12, a capacitor C7 and a 5V power supply provide working conditions for the logic AND gate, and the output end of the logic AND gate is electrically connected with a b electrode of a triode Q13 through a resistor R37 and a triode Q10, so that the switching-off of the sub-switching circuit is controlled; the output end of the logic AND gate is also electrically connected with the negative electrode input end of the universal operational amplifier U1B through a resistor R34, a triode Q11 and a resistor R41, and the function of feeding back a signal at the output end of the logic AND gate to the universal operational amplifier U1B is realized; the logic and gate and its peripheral circuits constitute a protection execution circuit unit 7.
The working principle of the circuit of the embodiment is as follows: when the load is needed to do work, the effective level is input at the signal input end, for the convenience of expression, the triode Q13 adopts an NPN type triode, namely the effective level is the high level. The signal input end inputs high level, the triode Q13 is conducted, conducting voltage is generated at the two ends S and G of the PMOS tube, the PMOS tube is conducted, the voltage of the power supply end is transmitted to the NMOS tube, the two ends G and S of the NMOS tube generate conducting voltage, the NMOS tube is conducted, the load loop is conducted, and the load is electrified to do work;
in the process of load work doing, the universal operational amplifier U1B tracks the state of a load loop in real time, and the positive input end and the negative input end of the universal operational amplifier U1B respectively collect the voltages at two ends of a sampling resistor; by setting the resistance values of the resistor R33, the resistor R34 and the resistor R39, the voltage value acquired by the negative input end of the universal operational amplifier U1B in the normal state of a load circuit is larger than the voltage value acquired by the positive input end of the universal operational amplifier U1B, and at the moment, the universal operational amplifier U1B inputs a low level; the low level is input to the 1 pin input end of the logic AND gate, the 2 pin input end of the logic AND gate is electrically connected with the load signal input end, and at the moment, the logic AND gate is in a high level state, one high input end and one low input end do not meet the conducting condition of the logic AND gate, and the logic AND gate is in a turn-off state.
When the overload condition occurs to the load loop due to faults, the voltage division of the sampling resistor R27 is overlarge, the voltage value acquired by the negative electrode input end of the universal operational amplifier U1B is lower than the voltage value acquired by the positive electrode input end, and at the moment, the output end of the universal operational amplifier U1B outputs high level; the two input ends of the logic AND gate are both high level, the logic AND gate meets the conduction condition and outputs high level, the high level is transmitted to the b pole of the triode Q10, the triode Q10 is conducted, the e pole of the triode Q10 is grounded, the b pole of the triode Q13 is pulled to be low level after the triode Q10 is conducted, the triode Q13 does not meet the conduction condition and is turned off, the PMOS tube and the NMOS tube are sequentially turned off by the disconnection of the sub-switch circuit, and accordingly, the load loop is turned off;
in synchronization, the high level output by the logic and gate is also transmitted to the triode Q11, the triode Q11 is turned on to pull the negative input terminal of the general operational amplifier U1B low, so that the voltage value collected by the negative input terminal of the general operational amplifier U1B is always lower than the voltage value collected by the positive input terminal, and therefore the output terminal of the general operational amplifier U1B keeps outputting the high level state, and accordingly, the load loop is kept in the off state. Thereby realizing the overload protection function.
The embodiment skillfully utilizes the MOS tube to realize the on-off of the load loop, and has the advantages of simple and non-redundant circuit design, high circuit stability, small working current, weak current environment, high safety performance, low power consumption, environmental protection and energy conservation; the phenomenon of arc striking is avoided, and the service life of the product is long; the related electronic devices are common chips in the market, so that the production cost is effectively controlled, the integration degree is high, the occupied space is small, and the miniaturization requirement of the central control box is met; the embodiment has powerful functions, monitors the loop state in real time in the process of acting by a load, automatically cuts off the loop if the overload is abnormal, and keeps the loop in the cut-off state before maintenance; the circuit for realizing the function is ingenious and concise in design, and the function of the product is realized and the stability of the circuit is ensured by using the least components; the embodiment breaks through the design thinking of the traditional central control box based on relay design and has extremely important significance in the technical field of central electric appliance control.
Example 4:
as shown in fig. 7 to 8 of the attached drawings of the specification, in addition to embodiment 3, the present embodiment is further designed with an alarm unit, and the alarm unit is controlled by the protection execution circuit unit 7. The alarm unit comprises an alarm sub-switch circuit and a light-emitting diode, and the alarm sub-switch circuit is electrically connected with the output end of the logic AND gate.
The specific circuit of the embodiment is as follows: the LED driving circuit comprises a light emitting diode D7, a resistor R28, a triode Q9 and a resistor 30, wherein the output end of a logic AND gate is electrically connected with the b pole of the triode Q9 through the resistor 30, the e pole of the triode Q9 is grounded, the c pole of the triode Q9 is electrically connected with the cathode of the light emitting diode D7 through the resistor R28, and the anode of the light emitting diode D7 is connected with a working power supply.
When the overload condition occurs in the load loop, the high level output by the output end of the logic AND gate is transmitted to the b electrode of the triode Q9, the triode Q9 is conducted, the light-emitting diode D7 and the resistor R28 form a conducting loop, and the light-emitting diode D7 emits light to play a role in alarming.
The alarm circuit has an alarm function, which side has a fault is clear at a glance, and the alarm circuit can be realized by using a small number of components, so that the cost is low;
example 5:
a central control box can be used in electrical equipment such as tractors, automobiles and the like. The central control box of the present embodiment applies the switch control circuit of the present application. The electronic device related to the switch control circuit of the application has the advantages of small volume, high integration degree and small occupied space, and the miniaturization requirement of the central control box is met; and the components are common components in the market, so that the cost of the central control box is effectively controlled. The whole components are few in number and have no special requirements on models, and the components are common chips in the market, so that the production cost is effectively controlled; the design thinking of the traditional central control box is changed, and the central control box has extremely important significance in the technical field of central electric appliance control.
Therefore, the invention is not to be limited to the specific embodiments, but rather, all equivalent changes and modifications in the shapes, structures, characteristics and spirit of the invention are intended to be included within the scope of the appended claims.

Claims (7)

1. A switch control circuit comprising an input power supply (1), characterized in that: the device also comprises a load signal input end (2), an MOS tube switch control circuit module (3) and a load (4); the input power supply (1) provides a working power supply for the MOS tube switch control circuit module (3); the output end of the MOS tube switch control circuit module (3) is electrically connected with the load (4), and the output end of the MOS tube switch control circuit module controls the on and off of a load loop according to an input signal of the load signal input end (2);
the MOS tube switch control circuit module (3) comprises a load signal input end (2), an NMOS tube, a PMOS tube and a sub-switch circuit; the load signal input end (2) is electrically connected with the PMOS tube through a sub-switch circuit, and the sub-switch circuit controls the PMOS tube to be switched on and off; the PMOS tube is electrically connected with the NMOS tube and is used for controlling the connection and disconnection of the NMOS tube; the input power supply (1), the NMOS tube and the load (4) form the load loop, and the on and off of the NMOS tube determine the on and off of the load loop;
the sub-switch circuit comprises a triode Q13, and the b pole of the triode Q13 is electrically connected with the load signal input end (2) through a resistor R51; the e pole of the triode Q13 is grounded; the c electrode of the triode Q13 is electrically connected with the G electrode of the PMOS tube and one end of the resistor R47 through the resistor R49, the other end of the resistor R47 is electrically connected with the S electrode of the PMOS tube, and the S electrode of the PMOS tube is also electrically connected with a power supply end; the D electrode of the PMOS tube is electrically connected with one end of a resistor R44, and the other end of the resistor R44 is grounded and is electrically connected with the G end of the NMOS tube; the NMOS tube S is connected with the load (4), and the end S of the NMOS tube and the end G of the NMOS tube are electrically connected with a voltage stabilizing tube D9; the end D of the NMOS tube is electrically connected with the input power supply (1);
a capacitor C10 for filtering is electrically connected between the resistor R44 and the ground, and a resistor R46 for voltage division is connected in parallel at two ends of the capacitor C10.
2. The switch control circuit of claim 1, wherein: the switch control circuit also comprises a main control module (5), wherein the main control module (5) comprises a state tracking circuit unit (6) and a protection execution circuit unit (7); the state tracking circuit unit (6) collects sampling voltage on the MOS tube switch control circuit module (3), the input end of the state tracking circuit unit is electrically connected with the MOS tube switch control circuit module (3), the output end of the state tracking circuit unit is electrically connected with the protection execution circuit unit (7), and the protection execution circuit unit (7) is used for switching off the MOS tube switch control circuit module (3) and controlling the MOS tube switch control circuit module (3) to be in a state of keeping switching off.
3. The switch control circuit of claim 2, wherein: the state tracking circuit unit (6) takes a general operational amplifier as a core, and the protection execution circuit unit (7) takes a logic AND gate as a core; the positive end and the negative end of the general operational amplifier respectively collect the voltage at two ends of a sampling resistor on the MOS tube switch control circuit module (3); the output end of the general operational amplifier is electrically connected with one input end of the logic AND gate, and the other input end of the logic AND gate is electrically connected with the load signal input end (2); the output end of the logic AND gate is electrically connected with the MOS tube switch control circuit module (3) to control the turn-off of the MOS tube switch control circuit module (3); the output end of the logic AND gate also feeds back an electric signal to the state tracking circuit unit (6) through a feedback circuit, and the MOS tube switch control circuit module (3) is kept in a turn-off state all the time through the state tracking circuit unit (6) and the protection execution circuit unit (7).
4. The switch control circuit of claim 3, wherein: the switch control circuit also comprises an alarm unit which is controlled by the protection execution circuit unit (7).
5. The switch control circuit of claim 4, wherein: the alarm unit comprises an alarm sub-switch circuit and a light-emitting diode, and the alarm sub-switch circuit is electrically connected with the output end of the logic AND gate.
6. A method of controlling a switch control circuit according to any one of claims 1 to 5, the method comprising:
the load signal input end (2) inputs an effective level, the sub-switch circuit is conducted, the PMOS tube is conducted due to the fact that the conduction condition is met, the NMOS tube is conducted due to the fact that the conduction condition is met after the PMOS tube is conducted, the NMOS tube is conducted to enable a load loop to be conducted, and the load (4) normally does work;
the load circuit is electrically connected with a sampling resistor, and the positive input end and the negative input end of the general operational amplifier respectively collect the voltages at the two ends of the sampling resistor; judging according to the acquired voltage value, wherein the voltage value acquired by the negative end of the general operational amplifier is larger than the voltage value acquired by the positive end of the general operational amplifier, and the output end of the general operational amplifier outputs an invalid level; the logic AND gate electrically connected with the output end of the general operational amplifier is in a turn-off state because the logic AND gate does not meet the turn-on condition; at the moment, the load (4) on the load circuit is in a normal work-doing state;
when the overload condition of the load loop occurs due to faults, voltages at two ends of the sampling resistor are abnormal, the voltage value acquired by the negative end of the general operational amplifier is smaller than the voltage value acquired by the positive end of the general operational amplifier, and at the moment, the output end of the general operational amplifier outputs an effective level; one input end of the logic AND gate is electrically connected with the output end of the general operational amplifier and is in an effective level, the other input end of the logic AND gate is electrically connected with the load signal input end (2) and is also in an effective level, and the logic AND gate outputs the effective level at the moment; the effective level output by the logic AND gate turns off the sub-switch circuit, the PMOS tube is turned off because the PMOS tube does not meet the conduction condition, the NMOS tube is turned off because the PMOS tube does not meet the conduction condition after being turned off, and the NMOS tube is turned off to turn off the load loop; meanwhile, the effective level output by the logic AND gate is also fed back to the negative terminal of the general operational amplifier, so that the voltage value of the negative terminal of the general operational amplifier is kept in a state of being smaller than the voltage value of the positive terminal of the general operational amplifier, and the output end of the general operational amplifier keeps outputting the effective level, thereby keeping the load loop in a turn-off state.
7. A central control box, its characterized in that: the switch control circuit of any one of claims 1-6 is applied in the central control box.
CN201910945411.0A 2019-09-30 2019-09-30 Switch control circuit, control method and central control box applying same Active CN110658882B (en)

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CN204290283U (en) * 2013-12-11 2015-04-22 成都芯源系统有限公司 Short-circuit protection circuit and switching power supply thereof
JP2016192866A (en) * 2015-03-31 2016-11-10 株式会社豊田自動織機 Drive device
CN206164702U (en) * 2016-10-28 2017-05-10 广州视源电子科技股份有限公司 Current switching circuit, TV power board, TV mainboard and TV
CN207251571U (en) * 2017-07-18 2018-04-17 深圳市航天新源科技有限公司 Possesses the current limliting time delayed turn-off on-off circuit of the repeatable triggering of overcurrent memory function
CN108963986A (en) * 2018-06-06 2018-12-07 北京平高清大科技发展有限公司 A kind of energy supply protection circuit

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN203027228U (en) * 2012-12-20 2013-06-26 深圳Tcl新技术有限公司 Soft start electronic switch and direct current power supply
CN204290283U (en) * 2013-12-11 2015-04-22 成都芯源系统有限公司 Short-circuit protection circuit and switching power supply thereof
CN103885382A (en) * 2014-03-18 2014-06-25 深圳市汇川控制技术有限公司 PLC output circuit with overcurrent protection
JP2016192866A (en) * 2015-03-31 2016-11-10 株式会社豊田自動織機 Drive device
CN206164702U (en) * 2016-10-28 2017-05-10 广州视源电子科技股份有限公司 Current switching circuit, TV power board, TV mainboard and TV
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Inventor after: Jiang Yongyu

Inventor after: Li Gongjie

Inventor after: Xue Long

Inventor before: Jiang Yongyu

Inventor before: Li Gongjie

Inventor before: Jiang Long