Output protection circuit and output protection device

Abstract

The invention relates to the technical field of electronic circuits, in particular to an output protection circuit and an output protection device.The protection circuit comprises a control unit, a first comparison unit, a driving unit, a second comparison unit and a protection unit; the first comparison unit is respectively connected with the control unit, the driving unit and the protection unit; the second comparison unit is respectively connected with the driving unit and the protection unit; the control unit is used for transmitting a first control signal to the first comparison unit to control the first comparison unit to output a driving signal to the driving unit, so that the driving unit drives a load to operate; the second comparison unit is used for collecting a first sampling signal of the driving unit and outputting a state signal of the load according to the first sampling signal; the protection unit is used for transmitting a second control signal to the first comparison unit according to the state signal to control the first comparison unit to output a stop signal to the driving unit, so that the driving unit stops driving the load to operate. The size and the cost of the circuit can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to an output protection circuit and an output protection device. Background Art

[0002] In existing circuit devices, the driving circuit and the protection circuit are usually independently structured. The driving circuit and the protection circuit are combined through a hardware structure to have both the driving function and the protection function, but this often requires a structure such as multiple chips. Summary of the invention

[0003] In view of this, the embodiments of the present application provide an output protection circuit and an output protection device, which can effectively reduce the number of chips and other structures and reduce costs.

[0004] In a first aspect, an embodiment of the present application provides an output protection circuit, comprising: a control unit, a first comparison unit, a driving unit, a second comparison unit and a protection unit;

[0005] The first comparison unit is respectively connected to the control unit, the driving unit and the protection unit; the second comparison unit is respectively connected to the driving unit and the protection unit;

[0006] The control unit is used to transmit a first control signal to the first comparing unit to control the first comparing unit to output a driving signal to the driving unit, so that the driving unit drives the load to operate;

[0007] The second comparing unit is used to collect a first sampling signal of the driving unit, and output a state signal of the load according to the first sampling signal;

[0008] The protection unit is used to transmit a second control signal to the first comparison unit according to the state signal, so as to control the first comparison unit to output a stop signal to the driving unit, so that the driving unit stops driving the load to operate.

[0009] In some implementations, based on the above output protection circuit, the first comparison unit includes a first operational amplifier and an input resistor;

[0010] A first input terminal of the first operational amplifier is connected to the control unit, a second input terminal of the first operational amplifier is grounded through the input resistor, and an output terminal of the first operational amplifier is connected to the driving unit;

[0011] The first operational amplifier is used to output the driving signal when the voltage of the non-inverting input terminal is higher than the voltage of the inverting input terminal; the first operational amplifier is also used to output a stop signal to shut down the driving unit when the voltage of the non-inverting input terminal is lower than the voltage of the inverting input terminal, so that the load stops running, wherein the non-inverting input terminal and the inverting input terminal of the first operational amplifier are one of the first input terminal and the second input terminal of the first operational amplifier.

[0012] In some embodiments, based on the above output protection circuit, the protection unit includes an energy storage capacitor;

[0013] The protection unit is configured to transmit the second control signal to the first comparison unit when the second comparison unit outputs the first level signal;

[0014] The energy storage capacitor is used to be in a first charging and discharging state when the second comparing unit outputs a first level signal; and to be in a second charging and discharging state when the first level signal output by the second comparing unit changes to a second level signal, so as to extend the second control signal.

[0015] In some embodiments, based on the above-mentioned output protection circuit, when the non-inverting input terminal of the first operational amplifier is the first input terminal, and the inverting input terminal of the first operational amplifier is the second input terminal, the first charge-discharge state is a charging state, and the second charge-discharge state is a discharging state;

[0016] When the inverting input terminal of the first operational amplifier is the first input terminal, and the non-inverting input terminal of the first operational amplifier is the second input terminal, the first charge-discharge state is a discharge state, and the second charge-discharge state is a charge state.

[0017] In some embodiments, based on the above output protection circuit, the protection unit further includes an adjustment resistor and a first diode; the first comparison unit includes a first operational amplifier and an input resistor; the second comparison unit includes a second operational amplifier;

[0018] One end of the regulating resistor is respectively connected to one end of the input resistor and the second input end of the first operational amplifier, and the other end of the regulating resistor is connected to the output end of the second operational amplifier through the first diode; the other end of the input resistor is configured to be connected to the first reference voltage signal;

[0019] One end of the energy storage capacitor is connected to the second input end of the first operational amplifier, and the other end of the energy storage capacitor is grounded;

[0020] The first diode is used to prevent the energy storage capacitor from reversely discharging to the second comparing unit.

[0021] In some embodiments, based on the above-mentioned output protection circuit, if the first input terminal of the first operational amplifier and the first input terminal of the second operational amplifier are both in-phase input terminals, and the second input terminal of the first operational amplifier and the second input terminal of the second operational amplifier are both inverting input terminals, then the cathode of the first diode is connected to the adjustment resistor, and the anode of the first diode is connected to the output terminal of the second operational amplifier;

[0022] If the first input terminal of the first operational amplifier and the first input terminal of the second operational amplifier are both inverting input terminals, and the second input terminal of the first operational amplifier and the second input terminal of the second operational amplifier are both non-inverting input terminals, the anode of the first diode is connected to the adjustment resistor, and the cathode of the first diode is connected to the output terminal of the second operational amplifier.

[0023] In some implementations, based on the above output protection circuit, the driving unit includes a MOS tube; the second comparison unit includes a second operational amplifier, a filter resistor and a first filter capacitor;

[0024] One end of the filter resistor is connected to the source of the MOS tube, the other end of the filter resistor is respectively connected to one end of the first filter capacitor and the first input end of the second operational amplifier, the other end of the first filter capacitor is grounded, the second input end of the second operational amplifier is configured to receive a second reference voltage signal, and the output end of the second operational amplifier is connected to the protection unit;

[0025] The second operational amplifier is used to compare the first sampling signal and the second reference voltage signal, and output the state signal.

[0026] In some implementations, based on the above output protection circuit, a sampling unit is further included, the second comparison unit includes a second operational amplifier, and the sampling unit includes a second sampling resistor and a third sampling resistor;

[0027] One end of the second sampling resistor is connected to the output end of the second operational amplifier, and the other end of the second sampling resistor is grounded through the third sampling resistor;

[0028] The control unit is connected to the other end of the second sampling resistor, and is used to obtain a second sampling signal through the second sampling resistor, and generate a third control signal according to the second sampling signal, wherein the third control signal is used to disconnect the driving unit to stop the load from working.

[0029] In some implementations, based on the above output protection circuit, the driving unit includes a driving resistor, a first sampling resistor and a MOS tube;

[0030] One end of the driving resistor is connected to the first comparison unit, the other end of the driving resistor is connected to the gate of the MOS tube, the source of the MOS tube is grounded through the first sampling resistor, and the drain of the MOS tube is used to connect to the load;

[0031] The driving unit is used to enable the load to operate when the MOS tube is turned on.

[0032] In some embodiments, based on the above output protection circuit, a freewheeling unit is further included, the freewheeling unit includes a second diode, the anode of the second diode is respectively connected to the drain of the MOS tube and the load, and the cathode of the second diode is configured to be connected to a preset voltage signal;

[0033] The freewheeling unit is used for freewheeling when the load is an inductive load.

[0034] In a second aspect, an embodiment of the present application further provides an output protection device, which includes the above-mentioned output protection circuit.

[0035] The embodiments of the present application have the following beneficial effects:

[0036] The present application proposes an output protection circuit, comprising: a control unit, a first comparison unit, a driving unit, a second comparison unit and a protection unit; the first comparison unit is respectively connected to the control unit, the driving unit and the protection unit; the second comparison unit is respectively connected to the driving unit and the protection unit; the control unit is used to transmit a first control signal to the first comparison unit to control the first comparison unit to output a driving signal to the driving unit, so that the driving unit drives the load to operate; the second comparison unit is used to collect a first sampling signal of the driving unit and output a state signal of the load according to the first sampling signal; the protection unit is used to transmit a second control signal to the first comparison unit according to the state signal to control the first comparison unit to output a stop signal to the driving unit, so that the driving unit stops driving the load to operate. The present application combines the driving unit and the protection unit on the premise of reducing the number of chips, and has both driving function and protection function, effectively reducing the circuit volume and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] 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. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 A first module schematic diagram of the output protection circuit proposed in an embodiment of the present application is shown;

[0039] Figure 2 A second module schematic diagram of the output protection circuit proposed in an embodiment of the present application is shown;

[0040] Figure 3 A third module schematic diagram of the output protection circuit proposed in the embodiment of the present application is shown;

[0041] Figure 4 A fourth module schematic diagram of the output protection circuit proposed in an embodiment of the present application is shown;

[0042] Figure 5 A fifth module schematic diagram of the output protection circuit proposed in the embodiment of the present application is shown.

[0043] Explanation of the main component symbols: 110-control unit; 120-first comparison unit; 130-driving unit; 140-second comparison unit; 150-protection unit; 160-sampling unit; 170-freewheeling unit; R1-driving resistor; R2-first sampling resistor; R3-input resistor; R4-adjusting resistor; R5-filtering resistor; R6-second sampling resistor; R7-third sampling resistor; U1-first operational amplifier; U2-second operational amplifier; Q-MOS tube; C1-energy storage capacitor; C2-first filter capacitor; C3-second filter capacitor; D1-first diode; D2-second diode. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0045] The components of the embodiments of the present application generally described and shown in the drawings herein may be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0046] Hereinafter, the terms "including", "having" and their cognates that can be used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or a combination of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or a combination of the foregoing items or increasing the possibility of one or more features, numbers, steps, operations, elements, components or a combination of the foregoing items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0047] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meanings as those generally understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meanings as the contextual meanings in the relevant technical field and will not be interpreted as having idealized meanings or overly formal meanings unless clearly defined in the various embodiments of the present application.

[0048] In conjunction with the accompanying drawings, some embodiments of the present application are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0049] Generally, the circuit formed by combining the driving circuit and the protection circuit not only has many components and a large volume, but also has a high cost.

[0050] Therefore, in order to solve the above problem, the present application proposes an output protection circuit.

[0051] The output protection circuit is described below in conjunction with some specific embodiments.

[0052] Figure 1 A schematic diagram of the structure of an output protection circuit according to an embodiment of the present application is shown. Exemplarily, the output protection circuit includes: a control unit 110 , a first comparison unit 120 , a driving unit 130 , a second comparison unit 140 and a protection unit 150 .

[0053] The first comparing unit 120 is respectively connected to the control unit 110 , the driving unit 130 , and the protecting unit 150 , and the second comparing unit 140 is respectively connected to the driving unit 130 and the protecting unit 150 .

[0054] The control unit 110 in this embodiment transmits a first control signal to the first comparing unit 120 according to the instruction, so as to control the first comparing unit 120 to output a driving signal to the driving unit 130, so that the driving unit 130 drives the load to operate.

[0055] It is understandable that the function of the first control signal is to make the first comparison unit 120 output a driving signal, which enables the driving unit 130 to drive the load to operate. Therefore, the first control signal here can be any level, depending on the specific designed circuit parameters, without limitation.

[0056] Exemplarily, if the first comparison unit 120 is designed such that when the first control signal input to the first comparison unit 120 is not less than 2.5V, the first comparison unit 120 outputs the above-mentioned driving signal, and the driving signal turns on the driving unit 130, thereby driving the load to operate, then the first control signal at this time can be a 3.3V level signal.

[0057] The second comparison unit 140 collects the first sampling signal of the driving unit 130 and outputs a state signal of the load according to the first sampling signal.

[0058] It can be understood that the operating state of the load can change the level of the first sampling signal. When the load is operating normally and when the load is short-circuited, the state signal output by the second comparison unit 140 is different. Among them, the state signal includes a normal state signal and an abnormal state signal. When the load is operating normally, the second comparison unit 140 outputs a normal state signal; when the load is abnormal (short circuit, etc.), the second comparison unit 140 outputs an abnormal state signal. It can be seen that the level of the normal state signal and the abnormal state signal are different.

[0059] Optionally, the normal state signal is a low level signal, and the abnormal state signal is a high level signal.

[0060] The protection unit 150 transmits a second control signal to the first comparison unit 120 according to the state signal, so as to control the first comparison unit 120 to output a stop signal to the driving unit 130 , so that the driving unit 130 stops driving the load to operate.

[0061] It is understandable that the second control signal output by the protection unit 150 can cause the first comparison unit 120 to output a stop signal, and the stop signal can disconnect the driving unit 130, thereby stopping the load from running.

[0062] In some embodiments, Figure 2 As shown, based on the above output protection circuit, the driving unit 130 includes a driving resistor R1, a first sampling resistor R2 and a MOS tube Q.

[0063] One end of the driving resistor R1 is connected to the first comparison unit 120 , the other end of the driving resistor R1 is connected to the gate of the MOS transistor Q, the source of the MOS transistor Q is grounded through the first sampling resistor R2 , and the drain of the MOS transistor Q is used to connect to the load.

[0064] It should be noted that the load has positive and negative terminals. If the load needs to run, the two terminals of the load form a closed loop. The drain of the MOS tube Q is connected to the negative terminal of the load, which is used to control the load to be grounded to form a closed loop. Therefore, when the MOS tube Q is turned on, the load is turned on and runs; when the MOS tube Q is turned off, the load is turned off and stops running. Therefore, the driving unit 130 can control the on and off of the load.

[0065] In some embodiments, reference Figure 2 or Figure 3 On the basis of the above output protection circuit, the first comparison unit 120 includes a first operational amplifier U1 and an input resistor R3. The first input terminal of the first operational amplifier U1 is connected to the control unit 110, the second input terminal of the first operational amplifier U1 is grounded through the input resistor R3, and the output terminal of the first operational amplifier U1 is connected to the driving unit 130.

[0066] When the voltage at the non-inverting input terminal of the first operational amplifier U1 is higher than the voltage at the inverting input terminal, the first operational amplifier U1 outputs a driving signal. When the voltage at the non-inverting input terminal of the first operational amplifier U1 is lower than the voltage at the inverting input terminal, the first operational amplifier U1 outputs a stop signal to turn off the driving unit 130, so that the load stops running. The non-inverting input terminal and the inverting input terminal of the first operational amplifier U1 are one of the first input terminal and the second input terminal of the first operational amplifier U1.

[0067] For example, Figure 2 As shown, the non-inverting input terminal of the first operational amplifier U1 is the first input terminal of the first operational amplifier U1 , and the inverting input terminal of the first operational amplifier U1 is the second input terminal of the first operational amplifier U1 .

[0068] For example, Figure 3 As shown, the inverting input terminal of the first operational amplifier U1 is the first input terminal of the first operational amplifier U1 , and the non-inverting input terminal of the first operational amplifier U1 is the second input terminal of the first operational amplifier U1 .

[0069] The non-inverting input terminal of the first operational amplifier U1 is used to receive a control signal of the control unit 110 , where the control signal includes the first control signal mentioned above.

[0070] Optionally, the first input terminal of the first operational amplifier U1 is further connected to a resistor to improve signal stability.

[0071] In some embodiments, reference Figure 2 or Figure 3 , based on the above output protection circuit, the protection unit 150 includes an energy storage capacitor C1.

[0072] When the second comparison unit 140 outputs a first level signal, the protection unit 150 transmits the above-mentioned second control signal to the first comparison unit 120, so that the first comparison unit 120 outputs the above-mentioned stop signal. When the second comparison unit 140 outputs a first level signal, the energy storage capacitor C1 is in a first charge-discharge state. When the first level signal output by the second comparison unit 140 becomes a second level signal, the energy storage capacitor C1 is in a second charge-discharge state to extend the second control signal. Among them, the first charge-discharge state and the second charge-discharge state are different, and the first charge-discharge state and the second charge-discharge state can be a charging state or a discharging state, which is not limited here.

[0073] For example, Figure 2 As shown, in this circuit, when the non-inverting input terminal of the first operational amplifier U1 is the first input terminal and the inverting input terminal of the first operational amplifier U1 is the second input terminal, the first charge-discharge state is the charging state, and the second charge-discharge state is the discharging state. The first level signal is a level signal greater than the voltage threshold (can be used as a high level signal), and the second level signal is a level signal not greater than the voltage threshold (can be used as a low level signal). In this circuit, the low level signal output by the second comparison unit 140 is normal state information, and the high level signal output by the second comparison unit 140 is abnormal state information.

[0074] It should be noted that the state signal includes a first level signal and a second level signal. The second comparison unit 140 is used to output the second level signal after the driving unit 130 receives the stop signal.

[0075] exist Figure 2 In the circuit, when the second comparison unit 140 outputs the first level signal (high level signal), the energy storage capacitor C1 is charged, and the protection unit 150 transmits the above-mentioned second control signal to the first comparison unit 120. At this time, the first comparison unit 120 outputs a stop signal to stop the driving unit 130 from driving the load to operate, and the first sampling signal collected by the second comparison unit 140 is a low level signal, and the second comparison unit 140 outputs a second level signal (low level signal). After the protection unit 150 receives the second level signal output by the second comparison unit 140, the energy storage capacitor C1 stops charging and starts discharging, and continues to maintain the high level of the inverting input terminal of the first operational amplifier U1, so that the protection unit 150 continues to transmit the second control signal to the first comparison unit 120 to extend the duration of the second control signal.

[0076] It is known that in Figure 2In the circuit, when the second comparison unit 140 outputs the first level signal, the protection unit 150 directly transmits the second control signal to the first comparison unit 120, so that the energy storage capacitor C1 can be quickly charged. When the first level signal output by the second comparison unit 140 is converted into the second level signal, the protection unit 150 cannot directly transmit the second control signal to the first comparison unit 120. At this time, the energy storage capacitor C1 is used to discharge to continue to transmit the second control signal. Therefore, the role of the energy storage capacitor C1 can extend the duration of the second control signal, which can effectively reduce the heating problem of the device caused by the short-circuit current of the circuit, delay the duration of the driving unit 130 closing (that is, driving the load to start running), and give the device time to dissipate heat.

[0077] For example, Figure 3 In the circuit, when the inverting input terminal of the first operational amplifier U1 is the first input terminal and the non-inverting input terminal of the first operational amplifier U1 is the second input terminal, the first charge-discharge state is the discharge state, and the second charge-discharge state is the charge state. The first level signal is a level signal not greater than the voltage threshold (can be used as a low level signal), and the second level signal is a level signal greater than the voltage threshold (can be used as a high level signal). In the circuit, the high level signal output by the second comparison unit 140 is normal state information, and the low level signal output by the second comparison unit 140 is abnormal state information.

[0078] exist Figure 3 In the circuit, when the second comparison unit 140 outputs the first level signal (low level signal), the energy storage capacitor C1 is discharged, and the protection unit 150 transmits the above-mentioned second control signal to the first comparison unit 120. At this time, the first comparison unit 120 outputs a stop signal to stop the driving unit 130 from driving the load to operate, and the first sampling signal collected by the second comparison unit 140 is a low level signal, and the second comparison unit 140 outputs a second level signal (high level signal). After the protection unit 150 receives the second level signal output by the second comparison unit 140, the energy storage capacitor C1 stops discharging and starts charging, maintaining the low level of the non-inverting input terminal of the first operational amplifier U1, so that the protection unit 150 continues to transmit the second control signal to the first comparison unit 120 to extend the duration of the second control signal.

[0079] It is known that in Figure 3In the circuit, when the second comparison unit 140 outputs the first level signal, the protection unit 150 directly transmits the second control signal to the first comparison unit 120, so that the energy storage capacitor C1 can be quickly charged. When the first level signal output by the second comparison unit 140 is converted into the second level signal, the protection unit 150 cannot directly transmit the second control signal to the first comparison unit 120. At this time, the energy storage capacitor C1 is used to charge to continue to transmit the second control signal. Therefore, the role of the energy storage capacitor C1 can extend the duration of the second control signal, which can effectively reduce the heating problem of the device caused by the short-circuit current of the circuit, delay the duration of the driving unit 130 closing (that is, driving the load to start running), and give the device time to dissipate heat.

[0080] In some embodiments, reference Figure 2 On the basis of the above output protection circuit, the protection unit 150 includes an adjustment resistor R4; the first comparison unit 120 includes a first operational amplifier U1 and an input resistor R3. One end of the adjustment resistor R4 is respectively connected to one end of the input resistor R3 and the second input end of the first operational amplifier U1, and the other end of the adjustment resistor R4 is connected to the second comparison unit 140; the other end of the input resistor R3 is configured to be connected to the first reference voltage, one end of the energy storage capacitor C1 is connected to the second input end of the first operational amplifier, and the other end of the energy storage capacitor C1 is grounded.

[0081] The first reference voltage is configured according to different circuit structures, and can be a high level signal or a low level signal without limitation.

[0082] For example, Figure 2 As shown, in the circuit, the first reference voltage is at a low level, and the other end of the input resistor R3 is grounded.

[0083] For example, Figure 3 As shown, in this circuit, the first reference voltage is a high level, such as 3.3V, etc., which is not limited here.

[0084] It should be noted that the adjustment resistor R4 is used to adjust the charging speed of the energy storage capacitor C1, and the input resistor R3 is also used to adjust the discharge time of the energy storage capacitor C1. When the adjustment resistor R4 is smaller, the charging time of the energy storage capacitor C1 is shorter and the speed is faster. The larger the input resistor R3 is, the longer the discharge time of the energy storage capacitor C1 is.

[0085] Exemplarily, if the input resistor R3 is 100k ohms and the adjustment resistor R4 is 1k ohms, the charging time of the energy storage capacitor C1 is much shorter than the discharging time. It should be understood that 100k and 1k here are only examples to emphasize that the resistance values ​​of the input resistor R3 and the adjustment resistor R4 should differ by different orders of magnitude, thereby ensuring that the charging time and discharging time of the energy storage capacitor C1 should differ significantly.

[0086] In the above solution, optionally, the charging current of the capacitor is greater than the discharging current of the capacitor.

[0087] It should be noted that during the discharging process of the energy storage capacitor C1, when the voltage at the inverting input terminal of the first operational amplifier U1 is lower than the voltage at the non-inverting input terminal of the first operational amplifier U1, the first comparison unit 120 outputs the above driving signal.

[0088] In some embodiments, reference Figure 2 On the basis of the above output protection circuit, the protection unit 150 further includes a first diode D1. The other end of the regulating resistor R4 is connected to the output end of the second operational amplifier U2 through the first diode D1. The first diode D1 is used to prevent the energy storage capacitor C1 from reversely discharging and protect the second comparison unit 140.

[0089] The specific connection condition with the first diode D1 needs to be set according to the structure of the output protection circuit, and is not limited here.

[0090] For example, Figure 2 As shown, if the first input terminal of the first operational amplifier U1 and the first input terminal of the second operational amplifier U2 are both in-phase input terminals, and the second input terminal of the first operational amplifier U1 and the second input terminal of the second operational amplifier U2 are both inverting input terminals, then the cathode of the first diode D1 is connected to the adjustment resistor R4, and the anode of the first diode D1 is connected to the output terminal of the second operational amplifier U2.

[0091] For example, Figure 3 As shown, if the first input terminal of the first operational amplifier U1 and the first input terminal of the second operational amplifier U2 are both inverting input terminals, and the second input terminal of the first operational amplifier U1 and the second input terminal of the second operational amplifier U2 are both non-inverting input terminals, then the anode of the first diode D1 is connected to the adjustment resistor R4, and the cathode of the first diode D1 is connected to the output terminal of the second operational amplifier U2.

[0092] In some embodiments, reference Figure 2 On the basis of the above output protection circuit, the driving unit 130 includes a MOS tube Q; the second comparing unit 140 includes a second operational amplifier U2, a filter resistor R5 and a first filter capacitor C2.

[0093] One end of the filter resistor R5 is connected to the source of the MOS tube Q, and the other end of the filter resistor R5 is respectively connected to one end of the first filter capacitor C2 and the first input end of the second operational amplifier U2, the other end of the first filter capacitor C2 is grounded, the second input end of the second operational amplifier U2 is configured to access the second reference voltage signal, and the output end of the second operational amplifier U2 is connected to the protection unit 150. The filter resistor R5 and the first filter capacitor C2 constitute an RC filter subunit, which is used for filtering and eliminating interference signals.

[0094] The second operational amplifier U2 is used to compare the first sampling signal with the second reference voltage signal and output a state signal, wherein the first sampling signal includes an abnormal level signal and a normal level signal.

[0095] Understandably, when the load operates abnormally and causes the current to rise, the first sampling signal is an abnormal level signal, and the second operational amplifier U2 outputs a first level signal. When the load operates normally and the first sampling signal is a normal level signal, the second operational amplifier U2 outputs a second level signal. When the load is abnormal and causes the current to rise, the first sampling signal will gradually rise until it is greater than the second reference voltage signal.

[0096] It should be noted that when the first sampling signal is lower than the second reference voltage signal, the first sampling signal is regarded as a normal level signal; when the first sampling signal is not lower than the second reference voltage signal, the first sampling signal is regarded as an abnormal level signal.

[0097] For example, Figure 2 As shown, when the first input terminal of the second operational amplifier U2 is a non-inverting input terminal and the second input terminal is an inverting input terminal, if the load works normally and the first sampling signal is 3.3 V, the second reference voltage signal can be 3.3 V. The second reference voltage signal is the same as or higher than the first sampling signal when the load works normally, so that when the load works normally, the second comparison unit 140 outputs a low level signal.

[0098] For example, Figure 3 As shown, when the first input terminal of the second operational amplifier U2 is an inverting input terminal and the second input terminal is a non-inverting input terminal, if the load is working normally and the first sampling signal is 3.3 V, the second reference voltage signal can be 3.8 V. The second reference voltage signal is higher than the first sampling signal when the load is working normally, so that when the load is working normally, the second comparison unit 140 outputs a high level signal.

[0099] In some embodiments, Figure 2 As shown, on the basis of the above output protection circuit, the second comparison unit 140 further includes a second filter capacitor C3, one end of which is connected to the inverting input end of the second operational amplifier U2 for filtering.

[0100] In some embodiments, Figure 4 As shown, based on the above output protection circuit, a sampling unit 160 is further included. The sampling unit 160 includes a second sampling resistor R6 and a third sampling resistor R7.

[0101] One end of the second sampling resistor R6 is connected to the second comparing unit 140 , and the other end of the second sampling resistor R6 is grounded through the third sampling resistor R7 .

[0102] The control unit 110 is connected to the other end of the second sampling resistor R6, and is used to obtain a second sampling signal through the second sampling resistor R6, and generate a third control signal according to the second sampling signal, wherein the third control signal is used to disconnect the driving unit 130 to stop the load from working.

[0103] It can be understood that, if the operating conditions of the load are different, the signal output by the second comparison unit 140 will be different, and the second sampling signal sampled by the control unit 110 will be different.

[0104] For example, Figure 2 As shown, when the second comparison unit 140 outputs a high level signal, the second sampling signal acquired by the control unit 110 is a high level signal. When the second comparison unit 140 outputs a low level signal, the second sampling signal acquired by the control unit 110 is a low level signal.

[0105] The effect of this embodiment is that, at the software level, when the current caused by the abnormal load is too large, the driving unit 130 can be turned off, thereby stopping the load operation.

[0106] The protection unit 150 in this embodiment protects the entire circuit at the hardware level. At the hardware level, when the load abnormality causes excessive current, the drive circuit can be quickly shut down to achieve load shutdown more quickly. In addition, the protection unit 150 can also effectively delay the state of load shutdown to increase the time for hardware heat dissipation.

[0107] By adding software-level protection on the basis of the protection unit 150, double protection can be achieved.

[0108] In some embodiments, Figure 5 As shown, on the basis of the above output protection circuit, a freewheeling unit 170 is further included, and the freewheeling unit 170 includes a second diode D2, the anode of the second diode D2 is respectively connected to the drain of the MOS tube Q and the load, and the cathode of the second diode D2 is configured to be connected to a preset voltage. The freewheeling unit 170 is used to perform freewheeling when the load is an inductive load to protect the MOS tube Q in the driving unit 130.

[0109] Exemplarily, the preset voltage may be 5V, etc., which is not limited here and is set according to the specific application scenario.

[0110] Under the premise of reducing the number of chips, the present application combines the structures of the driving unit 130 and the protection unit 150, and has both driving function and protection function, thereby effectively reducing the circuit volume and cost.

[0111] Another embodiment of the present application further provides an output protection device, which includes the above-mentioned output protection circuit.

[0112] It can be understood that the device of this embodiment corresponds to the protection circuit of the above embodiment, and the options in the above embodiment are also applicable to this embodiment, so they will not be described repeatedly here.

[0113] The control unit 110 of the present application includes a processor and a memory, wherein the memory stores a computer program, and the processor runs the computer program, thereby enabling the control unit 110 to perform the above-mentioned functions such as sending the first control signal and the third control signal to the first comparison unit 120.

[0114] Among them, the processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, including a central processing unit (CPU), a graphics processing unit (GPU) and a network processor (NP), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or at least one of other programmable logic devices, discrete gates or transistor logic devices, and discrete hardware components. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc., which can implement or execute the disclosed methods, steps and logic block diagrams in the embodiments of the present application.

[0115] The memory can be, but is not limited to, random access memory (RAM), read only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable read-only memory (EEPROM), etc.

[0116] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely schematic. For example, the flowcharts and structure diagrams in the accompanying drawings show the possible architecture, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in an alternative implementation, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the structure diagram and / or the flow diagram, and the combination of boxes in the structure diagram and / or the flow diagram, can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0117] In addition, the functional modules or units in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0118] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a smart phone, a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application.

[0119] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. An output protection circuit, characterized in that: include: A control unit, a first comparing unit, a driving unit, a second comparing unit and a protecting unit; The first comparison unit is respectively connected to the control unit, the driving unit and the protection unit; the second comparison unit is respectively connected to the driving unit and the protection unit; The control unit is used to transmit a first control signal to the first comparison unit to control the first comparison unit to output a driving signal to the driving unit, so that the driving unit drives the load to operate; The second comparing unit is used to collect a first sampling signal of the driving unit, and output a state signal of the load according to the first sampling signal; The protection unit is used to transmit a second control signal to the first comparison unit according to the state signal, so as to control the first comparison unit to output a stop signal to the driving unit, so that the driving unit stops driving the load to operate.

2. The output protection circuit according to claim 1, characterized in that: The first comparison unit includes a first operational amplifier and an input resistor; A first input terminal of the first operational amplifier is connected to the control unit, a second input terminal of the first operational amplifier is grounded through the input resistor, and an output terminal of the first operational amplifier is connected to the driving unit; The first operational amplifier is used to output the driving signal when the voltage of the non-inverting input terminal is higher than the voltage of the inverting input terminal; the first operational amplifier is also used to output a stop signal to shut down the driving unit when the voltage of the non-inverting input terminal is lower than the voltage of the inverting input terminal, so that the load stops running, wherein the non-inverting input terminal and the inverting input terminal of the first operational amplifier are one of the first input terminal and the second input terminal of the first operational amplifier.

3. The output protection circuit according to claim 2, characterized in that: The protection unit includes an energy storage capacitor; The protection unit is configured to transmit the second control signal to the first comparison unit when the second comparison unit outputs the first level signal; The energy storage capacitor is used to be in a first charging and discharging state when the second comparing unit outputs a first level signal; and to be in a second charging and discharging state when the first level signal output by the second comparing unit changes to a second level signal, so as to extend the second control signal.

4. The output protection circuit according to claim 3, characterized in that: When the non-inverting input terminal of the first operational amplifier is the first input terminal, and the inverting input terminal of the first operational amplifier is the second input terminal, the first charge-discharge state is a charging state, and the second charge-discharge state is a discharging state; When the inverting input terminal of the first operational amplifier is the first input terminal, and the non-inverting input terminal of the first operational amplifier is the second input terminal, the first charge-discharge state is a discharge state, and the second charge-discharge state is a charge state.

5. The output protection circuit according to claim 3, characterized in that: The protection unit further includes an adjustment resistor and a first diode; the first comparison unit includes a first operational amplifier and an input resistor; the second comparison unit includes a second operational amplifier; One end of the regulating resistor is respectively connected to one end of the input resistor and the second input end of the first operational amplifier, and the other end of the regulating resistor is connected to the output end of the second operational amplifier through the first diode; the other end of the input resistor is configured to be connected to the first reference voltage signal; One end of the energy storage capacitor is connected to the second input end of the first operational amplifier, and the other end of the energy storage capacitor is grounded; The first diode is used to prevent the energy storage capacitor from reversely discharging to the second comparing unit.

6. The output protection circuit according to claim 5, characterized in that: If the first input terminal of the first operational amplifier and the first input terminal of the second operational amplifier are both in-phase input terminals, and the second input terminal of the first operational amplifier and the second input terminal of the second operational amplifier are both inverting input terminals, the cathode of the first diode is connected to the regulating resistor, and the anode of the first diode is connected to the output terminal of the second operational amplifier; If the first input terminal of the first operational amplifier and the first input terminal of the second operational amplifier are both inverting input terminals, and the second input terminal of the first operational amplifier and the second input terminal of the second operational amplifier are both non-inverting input terminals, the anode of the first diode is connected to the adjustment resistor, and the cathode of the first diode is connected to the output terminal of the second operational amplifier.

7. The output protection circuit according to claim 2, characterized in that: The driving unit includes a MOS tube; the second comparing unit includes a second operational amplifier, a filter resistor and a first filter capacitor; One end of the filter resistor is connected to the source of the MOS tube, the other end of the filter resistor is respectively connected to one end of the first filter capacitor and the first input end of the second operational amplifier, the other end of the first filter capacitor is grounded, the second input end of the second operational amplifier is configured to receive a second reference voltage signal, and the output end of the second operational amplifier is connected to the protection unit; The second operational amplifier is used to compare the first sampling signal and the second reference voltage signal, and output the state signal.

8. The output protection circuit according to claim 1, characterized in that: It also includes a sampling unit, the second comparison unit includes a second operational amplifier, and the sampling unit includes a second sampling resistor and a third sampling resistor; One end of the second sampling resistor is connected to the output end of the second operational amplifier, and the other end of the second sampling resistor is grounded through the third sampling resistor; The control unit is connected to the other end of the second sampling resistor, and is used to obtain a second sampling signal through the second sampling resistor, and generate a third control signal according to the second sampling signal, wherein the third control signal is used to disconnect the driving unit to stop the load from working.

9. The output protection circuit according to claim 1, characterized in that: The driving unit includes a driving resistor, a first sampling resistor and a MOS tube; One end of the driving resistor is connected to the first comparison unit, the other end of the driving resistor is connected to the gate of the MOS tube, the source of the MOS tube is grounded through the first sampling resistor, and the drain of the MOS tube is used to connect to the load; The driving unit is used to enable the load to operate when the MOS tube is turned on.

10. The output protection circuit according to claim 9, characterized in that: It also includes a freewheeling unit, the freewheeling unit includes a second diode, the anode of the second diode is respectively connected to the drain of the MOS tube and the load, and the cathode of the second diode is configured to be connected to a preset voltage signal; The freewheeling unit is used for freewheeling when the load is an inductive load.

11. An output protection device, characterized in that: The output protection device comprises the output protection circuit according to any one of claims 1 to 10.

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