Load driving circuit

Abstract

This invention proposes a load driving circuit, including a power supply module, an overshoot protection circuit, a first switching module, and a power supply voltage abnormality protection circuit. The electrical terminals of the power supply module, the load to be driven, and the first switching module are connected in series and then grounded to form a load driving loop. The enable terminal of the first switching module is connected to the control signal output terminal of the main control circuit. When the main control circuit outputs a high-voltage control signal, the electrical terminals of the first switching module are turned on, and the load starts. The overshoot protection circuit is connected between the power supply module and the load to be driven, limiting the current at the moment the load is powered on and canceling the current limiting after the load stabilizes. The voltage abnormality protection circuit is connected between the power supply module and the first switching module. When the output voltage of the power supply module is abnormal, it controls the electrical terminals of the first switching module to open, and the load stops running. This invention can limit the large current at the moment of load startup and avoid damage to the load caused by abnormal power supply voltage.

Description

Technical Field

[0001] This invention belongs to the field of electronic circuit technology, and in particular relates to a load driving circuit. Background Technology

[0002] Today, DC motors are increasingly widely used in household appliances and power tools. A DC motor has fixed main magnetic poles and brushes mounted on its stator, and armature windings and a commutator mounted on its rotor. Electrical energy from a DC power supply enters the armature windings through the brushes and commutator, generating armature current. The magnetic field generated by this armature current interacts with the main magnetic field to produce electromagnetic torque, causing the motor to rotate and drive the load. As people's requirements for the stability and space utilization of control systems in household appliances and power tools increase, the control methods for DC motors are increasingly moving towards integration and modularity to save assembly space for the controller and motor.

[0003] However, the widespread use of integrated drive circuits has also created many situations where they are unsuitable for certain operating environments. For example, with the increasing popularity of lithium batteries, many power supply systems now use battery power. However, due to the inherent characteristics of DC motors, the large current at the moment of motor startup can cause instability in the power supply system. Conversely, voltage instability in the power supply system can also lead to unsatisfactory operation or even damage to the DC motor. Therefore, designing a load drive circuit that can both avoid the instability caused by the large current at the moment of load startup and protect the load in a timely manner when the power supply is unstable is a problem that urgently needs to be solved in the field of DC motor drives. Summary of the Invention

[0004] The present invention provides a load driving circuit to solve the problems mentioned in the background art, such as the instability of the power supply system caused by the large current at the moment of load start-up and the load damage caused by the power supply instability of the power supply system.

[0005] To achieve the above objectives, the specific technical solution of the load driving circuit of the present invention is as follows:

[0006] A load drive circuit includes a power supply module, an overshoot protection circuit, a first switching module, and a power supply voltage abnormality protection circuit.

[0007] The power supply module, the load to be driven, and the electrical terminals of the first switch module are connected in series and then grounded to form a load driving circuit; the enable terminal of the first switch module is connected to the control signal output terminal of the main control circuit. When the control signal output by the main control circuit is high, the electrical terminals of the first switch module are turned on, and the load is powered on and started.

[0008] The overshoot protection circuit is connected between the power module and the load to be driven, and is used to limit the current when the load is powered on and to cancel the current limiting after the load is running stably.

[0009] The voltage abnormality protection circuit is connected between the power supply module and the first switch module. When the output voltage of the power supply module is abnormal, the voltage abnormality protection circuit controls the electrical terminals of the first switch module to disconnect, and the load is de-energized and stops operating.

[0010] Furthermore, the power supply voltage abnormality protection circuit includes an undervoltage protection circuit, which includes a first Zener diode, a first resistor, and a second switching module. The cathode of the first Zener diode is connected to the power supply module, and the anode is connected to the first enable terminal of the second switching module. One end of the first resistor is connected to the power supply module, and the other end is connected to the second enable terminal of the second switching module. The electrical terminals of the second switching module are connected between the control signal output terminal of the main control circuit and ground. When the voltage of the power supply module is lower than a first preset voltage, the first Zener diode is turned off, the first enable terminal of the second switching module receives a low level signal, the second enable terminal of the second switching module receives a high level signal, the electrical terminals of the second switching module are turned on, the enable terminal of the first switching module is pulled down to a low level, and the electrical terminals of the first switching module are turned off.

[0011] Furthermore, the second switching module includes a first switching element and a second switching element. The enable terminal of the first switching element serves as the first enable terminal of the second switching module. The current input terminal of the electrical terminal of the first switching element is connected to the enable terminal of the second switching element, serving as the second enable terminal of the second switching module. The current output terminal of the electrical terminal of the first switching element is connected to the current output terminal of the electrical terminal of the second switching element. The electrical terminal of the second switching element serves as the electrical terminal of the second switching module. When the voltage of the power supply module is lower than the first preset voltage, the first Zener diode disconnects, the enable terminal of the first switching element receives a low-level signal, the electrical terminal of the first switching element is disconnected, the enable terminal of the second switching element receives a high-level signal, the electrical terminal of the second switching element is turned on, and the enable terminal of the first switching module is pulled down to a low level.

[0012] Furthermore, the voltage abnormality protection circuit includes an overvoltage protection circuit, which includes a second Zener diode, a second resistor, and a third switching element. The cathode of the second Zener diode is connected to the power module, and the anode is connected to one end of the second resistor and the enable terminal of the third switching element. The other end of the second resistor is grounded. The electrical terminal of the third switching element is connected between the control signal output terminal of the main control circuit and ground. When the voltage of the power module is higher than the second preset voltage, the second Zener diode is turned on, a high-level signal is input to the enable terminal of the third switching element, the electrical terminal of the third switching element is turned on, and the enable terminal of the first switching module is pulled low.

[0013] Furthermore, the load drive circuit also includes an overcurrent protection circuit, which includes a third resistor. One end of the third resistor is connected to the current output terminal of the electrical terminal of the first switching module and the enable terminal of the third switching element, and the other end of the third resistor is grounded. When the current in the load drive circuit is overcurrent, the voltage drop across the third resistor increases, the enable terminal of the third switching element receives a high-level signal, the electrical terminal of the third switching element is turned on, and the enable terminal of the first switching module is pulled low.

[0014] Furthermore, the load drive circuit also includes an overcurrent protection circuit, which includes a fourth resistor and a fourth switching element. One end of the fourth resistor is connected to the current output terminal of the electrical terminal of the first switching module and the enable terminal of the fourth switching element, and the other end of the fourth resistor is grounded. The electrical terminal of the fourth switching element is connected between the control signal output terminal of the control circuit and ground. When the current in the load drive circuit is overcurrent, the voltage drop across the fourth resistor increases, the enable terminal of the fourth switching element receives a high-level signal, the electrical terminal of the fourth switching element is turned on, and the enable terminal of the first switching module is pulled low.

[0015] Furthermore, the overshoot protection circuit includes a fifth resistor, a sixth resistor, a fifth switching element, and a first capacitor. One end of the fifth resistor and the current input terminal of the electrical terminal of the fifth switching element are connected to the power supply module. The other end of the fifth resistor and the current output terminal of the electrical terminal of the fifth switching element are connected to the load to be driven. The enable terminal of the fifth switching element is connected between the sixth resistor and the first capacitor. The other end of the sixth resistor is connected to the power supply module, and the other end of the first capacitor is grounded.

[0016] Furthermore, the undervoltage protection circuit also includes a seventh resistor, which is connected between the anode of the first Zener diode and the first enable terminal of the second switching module.

[0017] Furthermore, the overvoltage protection circuit also includes a third diode, the anode of which is connected to the connection node between the second resistor and the second Zener diode, and the cathode of which is connected to the enable terminal of the third switching element.

[0018] Furthermore, the overvoltage protection circuit also includes an eighth resistor, one end of which is connected to the enable terminal of the third switching element, and the other end is connected to the cathode of the third diode.

[0019] Furthermore, the overcurrent protection circuit also includes a fourth diode, the anode of which is connected to the connection node between the electrical terminal of the first switching module and the third resistor, and the cathode of which is connected to the connection node between the eighth resistor and the cathode of the third diode.

[0020] Furthermore, it also includes a fifth diode, the anode of which is connected to the control signal output terminal of the main control circuit, and the cathode is connected to the enable terminal of the first switching module.

[0021] Furthermore, the first switching module includes a sixth switching element, the enable terminal of the sixth switching element serves as the enable terminal of the first switching module, and the electrical terminal of the sixth switching element serves as the electrical terminal of the first switching module.

[0022] Furthermore, the first switching module also includes a ninth resistor, one end of which is connected to the enable terminal of the sixth switching element, and the other end of which serves as the enable terminal of the first switching module and is connected to the control signal output terminal of the main control circuit.

[0023] The present invention provides a load drive circuit that limits the large current at the moment of load start-up through an overshoot protection circuit and controls the electrical terminals of the first switching module to disconnect when the power supply voltage of the power module is abnormal through a power supply voltage abnormal protection circuit, thereby cutting off the load drive circuit and causing the load to stop running due to power failure, thus avoiding damage to the load caused by abnormal power supply voltage of the power module.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0025] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0026] Figure 1 A structural block diagram of a load driving circuit provided in one embodiment of the present invention;

[0027] Figure 2 A circuit diagram of a load driving circuit provided in one embodiment of the present invention;

[0028] Figure 3 A circuit diagram of a load driving circuit provided in another embodiment of the present invention;

[0029] Figure 4 A circuit diagram of a load driving circuit provided in another embodiment of the present invention;

[0030] 101. Power supply module; 102. Overshoot protection circuit; 103. Load; 104. First switch module; 105. Power supply voltage abnormality protection circuit; 106. Second switch module. Detailed Implementation

[0031] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0034] Figure 1 A schematic diagram illustrates a structural block diagram of a load drive circuit according to an embodiment, such as... Figure 1As shown, the load driving circuit of this embodiment includes a power supply module 101, an overshoot protection circuit 102, a first switch module 104, and a power supply voltage abnormality protection circuit 105. The electrical terminals of the power supply module 101, the load to be driven 103, and the first switch module 104 are connected in series and then grounded to form a load driving loop. The enable terminal of the first switch module 104 is connected to the control signal output terminal IO of the main control circuit. When the control signal output by the main control circuit is high, the electrical terminals of the first switch module 104 are turned on, and the load 103 is powered on and started. It is understood that the load 103 in this embodiment can be a DC motor or other types of loads; this invention does not limit the type of load.

[0035] The overshoot protection circuit 102 is connected between the power module 101 and the load 103 to be driven. It limits the current when the load 103 is powered on and cancels the current limiting after the load 103 is running stably. The power supply voltage abnormality protection circuit 105 is connected between the power module 101 and the first switch module 104. When the output voltage of the power module 101 is abnormal, the power supply voltage abnormality protection circuit 105 controls the electrical terminals of the first switch module 104 to open, and the load stops running. Specifically, the power supply voltage abnormality protection circuit 105 is connected between the control signal output terminal IO of the main control circuit and the enable terminal of the first switch module 104. When the output voltage of the power module 101 is abnormal, the power supply voltage abnormality protection circuit 105 pulls down the high-level signal of the control signal output terminal IO of the main control circuit, so that the enable terminal of the first switch module 104 inputs a low-level signal, the electrical terminals of the first switch module 104 are opened, and the load stops running.

[0036] Furthermore, since the abnormal power supply voltage of the power module 101 includes both undervoltage and overvoltage conditions, the power supply voltage abnormality protection circuit 105 of this embodiment of the invention also specifically includes an undervoltage protection circuit and an overvoltage protection circuit. In practical applications, the power supply voltage abnormality protection circuit 105 can be configured to include one or both of the undervoltage protection circuit and the overvoltage protection circuit as needed, and the present invention does not limit this.

[0037] To more clearly describe the circuit structure of the load drive circuit in the embodiments of the present invention, see attached... Figure 2 A schematic circuit diagram of a load drive circuit according to another embodiment of the present invention is shown. Figure 2As can be seen, the undervoltage protection circuit of the power supply voltage abnormality protection circuit 105 in this embodiment of the invention includes a first Zener diode D1, a first resistor R1, and a second switching module 106. The cathode of the first Zener diode D1 is connected to the power supply module 101, and the anode is connected to the first enable terminal of the second switching module 106. One end of the first resistor R1 is connected to the power supply module 101, and the other end is connected to the second enable terminal of the second switching module 106. The electrical terminals of the second switching module 106 are connected between the control signal output terminal IO of the main control circuit and ground. When the voltage of the power supply module 101 is lower than the first preset voltage, the first Zener diode D1 is turned off, the first enable terminal of the second switching module 106 receives a low level signal, the second enable terminal of the second switching module 106 receives a high level signal, the electrical terminals of the second switching module 106 are turned on, the enable terminal of the first switching module 104 is pulled down to a low level, and the electrical terminals of the first switching module 104 are turned off. When the voltage of power module 101 is higher than or equal to the first preset voltage, the first Zener diode D1 conducts, and the first enable terminal of the second switch module 106 receives a high level input. At this time, the second enable terminal of the second switch module 106 is pulled low, and the electrical terminals of the second switch module 106 are disconnected. Under the premise of no other abnormal conditions, the load operates normally. It should be noted that the first preset voltage is a preset undervoltage voltage, and the voltage value of the first preset voltage can be adjusted by replacing the first Zener diode D1 with different parameters.

[0038] Specifically, the second switching module 106 includes a first switching element Q1 and a second switching element Q2. In this embodiment, the switching element can be a transistor or a MOSFET, or other semiconductor switching device, as long as it can perform the switching function. The following explanation uses a transistor as an example. The enable terminal (i.e., base) of the first switching element Q1 serves as the first enable terminal of the second switching module 106. The current input terminal (i.e., collector) of the electrical terminal of the first switching element Q1 is connected to the enable terminal (i.e., base) of the second switching element Q2, serving as the second enable terminal of the second switching module 106. The current output terminal (i.e., emitter) of the electrical terminal of the first switching element Q1 is connected to the current output terminal (i.e., emitter) of the electrical terminal of the second switching element Q2. The electrical terminal of the second switching element Q2 serves as the electrical terminal of the second switching module 106, that is, the current input terminal (i.e., emitter) of the electrical terminal of the second switching element Q2. The collector of the first switching element Q1 is connected to the control signal output terminal IO of the main control circuit. The current output terminal (emitter) of the electrical terminal of the second switching element Q2 is grounded. When the voltage of the power module 101 is lower than the first preset voltage, the first Zener diode D1 is turned off, the enable terminal (base) of the first switching element Q1 is input with a low level, and the electrical terminal of the first switching element Q1 is turned off. At this time, the enable terminal (base) of the second switching element Q2 is input with a high level signal, and the electrical terminal of the second switching element Q2 is turned on. The enable terminal of the first switching module 104 is pulled down to a low level by the second switching element Q2, and the electrical terminal of the first switching module 104 is turned off. The load 103 is de-energized and stops running. When the voltage of the power module 101 is higher than or equal to the first preset voltage, the first Zener diode D1 is turned on, the enable terminal (i.e., base) of the first switching element Q1 is input with a high level, and the electrical terminal of the first switching element Q1 is turned on. At this time, the enable terminal (i.e., base) of the second switching element Q2 is pulled low by the electrical terminal of the first switching element Q1 and input with a low level signal. The electrical terminal of the second switching element Q2 is turned off. Under the premise that there are no other abnormal conditions, the electrical terminal of the first switching module 104 is turned on, and the load 103 operates normally.

[0039] Furthermore, the overvoltage protection circuit of the power supply voltage abnormality protection circuit 105 in this embodiment of the invention includes a second Zener diode D2, a second resistor R2, and a third switching element Q3. The cathode of the second Zener diode D2 is connected to the power module 101, and the anode is connected to one end of the second resistor R2 and the enable terminal of the third switching element Q3. The other end of the second resistor R2 is grounded. The electrical terminal of the third switching element Q3 is connected between the control signal output terminal IO of the control circuit and ground. When the voltage of the power module 101 is higher than the second preset voltage, the second Zener diode D2 is turned on, the enable terminal (i.e., the base) of the third switching element Q3 receives a high-level signal, the electrical terminal of the third switching element Q3 is turned on, the enable terminal of the first switching module 104 is pulled low, the electrical terminal of the first switching module 104 is disconnected, and the load is de-energized and stops operating. When the voltage of the power module 101 is lower than or equal to the second preset voltage, the second Zener diode D2 is disconnected, and a low-level signal is input to the enable terminal (i.e., base) of the third switching element Q3. Under normal circumstances, the electrical terminals of the third switching element Q3 are disconnected, the electrical terminals of the first switching module 104 are turned on, and the load 103 operates normally. It should be noted that the second preset voltage is a preset overvoltage, and its value can be adjusted by replacing the second Zener diode D2 and the second resistor R2 with different parameters.

[0040] Furthermore, the load drive circuit of this embodiment also includes an overcurrent protection circuit. The overcurrent protection circuit includes a third resistor R3. One end of the third resistor R3 is connected to the current output terminal of the electrical terminal of the first switch module 104 and the enable terminal (i.e., base) of the third switch element Q3. The other end of the third resistor R3 is grounded. When the current in the load drive circuit is excessive, the voltage drop across the third resistor R3 increases, the enable terminal (i.e., base) of the third switch element Q3 receives a high-level signal, the electrical terminal of the third switch element is turned on, the enable terminal of the first switch module 104 is pulled low, the electrical terminal of the first switch module 104 is turned off, and the load is de-energized and stops operating. When the current in the load drive circuit is lower than the overcurrent value, the voltage drop across the third resistor R3 is less than the trigger voltage of the third switch element Q3, the electrical terminal of the third switch element Q3 is turned off, the electrical terminal of the first switch module 104 is turned on, and the load 103 operates normally. It should be noted that, in this embodiment of the invention, the overcurrent protection current value can be adjusted by adjusting the resistance value of the third resistor R3.

[0041] Furthermore, the overshoot protection circuit of this embodiment includes a fifth resistor R5, a sixth resistor R6, a fifth switching element Q5, and a first capacitor C1. One end of the fifth resistor R5 and the current input terminal (i.e., collector) of the electrical terminal of the fifth switching element Q5 are connected to the power module 101. The other end of the fifth resistor R5 and the current output terminal (i.e., emitter) of the electrical terminal of the fifth switching element Q5 are connected to the load to be driven 103. The enable terminal (i.e., base) of the fifth switching element Q5 is connected between the sixth resistor R6 and the first capacitor C1. The other end of the sixth resistor R6 is connected to the power module 101, and the other end of the first capacitor C1 is grounded. At the moment the load is powered on, the power module 101 supplies power to the load through the fifth resistor R5, which acts as a current limiter. During the load startup process, the first capacitor C1 is charged through the sixth resistor R6. When the load is running stably, the voltage drop across the first capacitor C1 reaches the trigger voltage of the fifth switching element Q5. The electrical terminals of the fifth switching element Q5 bypass the fifth resistor R5. Since the fifth resistor R5 is no longer connected to the load circuit, the current limiting function is canceled.

[0042] In the load drive circuit of this embodiment, to improve the stability of the drive circuit and avoid interference from one branch to another, some protective resistors can be connected as needed to limit the magnitude of the current and protective diodes to limit the direction of the current. Specifically, the undervoltage protection circuit also includes a seventh resistor R7, which is connected between the anode of the first Zener diode D1 and the first enable terminal of the second switching module 106. The seventh resistor R7 limits the current of this branch when the power supply voltage is overvoltage. The overvoltage protection circuit also includes a third diode D3, which is connected to the connection node between the second resistor R2 and the second Zener diode D2. The cathode of the third diode D3 is connected to the enable terminal (i.e., the base) of the third switching element Q3. The third diode D3 defines the current direction and avoids interference from the current in the overcurrent protection circuit and the input current of the enable terminal of the first switching module 104 to the overvoltage protection circuit. The overvoltage protection circuit also includes an eighth resistor R8. One end of the eighth resistor R8 is connected to the enable terminal (i.e., base) of the third switching element Q3, and the other end is connected to the cathode of the third diode D3. This resistor limits the input current to the enable terminal (i.e., base) of the third switching element Q3 when the power supply voltage is too high. It can be understood that the eighth resistor R8 can also limit the input current to the enable terminal (i.e., base) of the third switching element Q3 when the load return current is too high. The overcurrent protection circuit also includes a fourth diode D4. The anode of the fourth diode D4 is connected to the connection node between the electrical terminal of the first switching module 104 and the third resistor R3, and the cathode of the fourth diode D4 is connected to the connection node between the ninth resistor and the cathode of the third diode D3. The fourth diode D4 avoids interference caused by the current in the overvoltage protection circuit and the input current of the enable terminal of the first switching module 104 to the overcurrent protection circuit. In addition, the load driving circuit of this embodiment of the invention also includes a fifth diode D5. The anode of the fifth diode D5 is connected to the control signal output terminal IO of the main control circuit, and the cathode is connected to the enable terminal of the first switch module 104. The fifth diode D5 avoids the interference caused by the current in the overvoltage protection circuit and the current in the overcurrent protection circuit to the current of the signal input terminal.

[0043] Furthermore, the first switching module 104 of the load driving circuit in this embodiment of the invention includes a sixth switching element Q6. The enable terminal (i.e., base) of the sixth switching element Q6 serves as the enable terminal of the first switching module 104, and the electrical terminals of the sixth switching element serve as the electrical terminals of the first switching module. To limit the input current of the enable terminal (i.e., base) of the sixth switching element Q6, the first switching module 104 also includes a ninth resistor R9. One end of the ninth resistor R9 is connected to the enable terminal (i.e., base) of the sixth switching element Q6, and the other end of the ninth resistor R9 serves as the enable terminal of the first switching module 104 and is connected to the control signal output terminal IO of the main control circuit.

[0044] This invention also includes alternative embodiments of overcurrent protection circuits, see attached. Figure 3 A schematic circuit diagram of a load driving circuit according to another embodiment of the present invention is shown. Figure 3 It is understood that the load drive circuit of this embodiment of the invention also includes an overcurrent protection circuit. The overcurrent protection circuit includes a fourth resistor R4 and a fourth switching element Q3. One end of the fourth resistor R4 is connected to the current output terminal of the electrical terminal of the first switching module 104 and the enable terminal (i.e., base) of the fourth switching element Q4. The other end of the fourth resistor R4 is grounded. The electrical terminal of the fourth switching element Q4 is connected between the control signal output terminal IO of the control circuit and ground. When the current in the load drive circuit is overcurrent, the voltage drop across the fourth resistor R4 increases, the enable terminal (i.e., base) of the fourth switching element Q4 receives a high-level signal, the electrical terminal of the fourth switching element is turned on, the enable terminal of the first switching module 104 is pulled low, the electrical terminal of the first switching module 104 is disconnected, and the load is de-energized and stops running. When the current in the load drive circuit is lower than the overcurrent value, the voltage drop across the fourth resistor R4 is less than the trigger voltage of the fourth switching element Q4, the electrical terminal of the fourth switching element Q4 is disconnected, the electrical terminal of the first switching module 104 is turned on, and the load 103 operates normally.

[0045] This embodiment provides a load drive circuit that limits the large current at the moment of load startup through an overshoot protection circuit, and controls the electrical terminals of the first switching module to disconnect when the power supply voltage of the power module is abnormal through a power supply voltage abnormal protection circuit, thereby cutting off the load drive circuit and causing the load to stop running due to power failure, thus avoiding damage to the load caused by abnormal power supply voltage of the power module.

[0046] Those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the claims, any of the claimed embodiments can be used in any combination.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A load driving circuit, characterized in that, Includes a power module, an overshoot protection circuit, a first switch module, and a power supply voltage abnormality protection circuit; The power supply module, the load to be driven, and the electrical terminals of the first switch module are connected in series and then grounded to form a load driving circuit; the enable terminal of the first switch module is connected to the control signal output terminal of the main control circuit. When the control signal output by the main control circuit is high, the electrical terminals of the first switch module are turned on, and the load is powered on and started. The overshoot protection circuit is connected between the power module and the load to be driven, and is used to limit the current when the load is powered on and to cancel the current limiting after the load is running stably. The voltage abnormality protection circuit is connected between the power supply module and the first switch module. When the output voltage of the power supply module is abnormal, the voltage abnormality protection circuit controls the electrical terminals of the first switch module to disconnect, and the load is de-energized and stops operating. The load drive circuit further includes an overcurrent protection circuit, which includes a fourth resistor and a fourth switching element. One end of the fourth resistor is connected to the current output terminal of the electrical terminal of the first switching module and the enable terminal of the fourth switching element. The other end of the fourth resistor is grounded. The electrical terminal of the fourth switching element is connected between the control signal output terminal of the control circuit and ground. When the current in the load drive circuit is overcurrent, the voltage drop across the fourth resistor increases, the enable terminal of the fourth switching element receives a high-level signal, the electrical terminal of the fourth switching element is turned on, and the enable terminal of the first switching module is pulled low.

2. The load drive circuit according to claim 1, characterized in that, The power supply voltage abnormality protection circuit includes an undervoltage protection circuit, which includes a first Zener diode, a first resistor, and a second switching module. The cathode of the first Zener diode is connected to the power supply module, and the anode is connected to the first enable terminal of the second switching module. One end of the first resistor is connected to the power supply module, and the other end is connected to the second enable terminal of the second switching module. The electrical terminals of the second switching module are connected between the control signal output terminal of the main control circuit and ground. When the voltage of the power supply module is lower than a first preset voltage, the first Zener diode is turned off, the first enable terminal of the second switching module receives a low level signal, the second enable terminal of the second switching module receives a high level signal, the electrical terminals of the second switching module are turned on, the enable terminal of the first switching module is pulled down to a low level, and the electrical terminals of the first switching module are turned off.

3. The load drive circuit according to claim 2, characterized in that, The second switching module includes a first switching element and a second switching element. The enable terminal of the first switching element serves as the first enable terminal of the second switching module. The current input terminal of the electrical terminal of the first switching element is connected to the enable terminal of the second switching element, serving as the second enable terminal of the second switching module. The current output terminal of the electrical terminal of the first switching element is connected to the current output terminal of the electrical terminal of the second switching element. The electrical terminal of the second switching element serves as the electrical terminal of the second switching module. When the voltage of the power supply module is lower than a first preset voltage, the first Zener diode disconnects, the enable terminal of the first switching element receives a low-level signal, the electrical terminal of the first switching element is disconnected, the enable terminal of the second switching element receives a high-level signal, the electrical terminal of the second switching element is turned on, and the enable terminal of the first switching module is pulled down to a low level.

4. The load drive circuit according to claim 1 or 2, characterized in that, The voltage abnormality protection circuit includes an overvoltage protection circuit, which includes a second Zener diode, a second resistor, and a third switching element. The cathode of the second Zener diode is connected to the power module, and the anode is connected to one end of the second resistor and the enable terminal of the third switching element. The other end of the second resistor is grounded. The electrical terminal of the third switching element is connected between the control signal output terminal of the main control circuit and ground. When the voltage of the power module is higher than the second preset voltage, the second Zener diode is turned on, a high-level signal is input to the enable terminal of the third switching element, the electrical terminal of the third switching element is turned on, and the enable terminal of the first switching module is pulled low.

5. The load drive circuit according to claim 4, characterized in that, The load drive circuit also includes an overcurrent protection circuit, which includes a third resistor. One end of the third resistor is connected to the current output terminal of the electrical terminal of the first switching module and the enable terminal of the third switching element. The other end of the third resistor is grounded. When the current in the load drive circuit is overcurrent, the voltage drop across the third resistor increases, the enable terminal of the third switching element receives a high-level signal, the electrical terminal of the third switching element is turned on, and the enable terminal of the first switching module is pulled low.

6. The load drive circuit according to claim 1, characterized in that, The overshoot protection circuit includes a fifth resistor, a sixth resistor, a fifth switching element, and a first capacitor. One end of the fifth resistor and the current input terminal of the electrical terminal of the fifth switching element are connected to the power supply module. The other end of the fifth resistor and the current output terminal of the electrical terminal of the fifth switching element are connected to the load to be driven. The enable terminal of the fifth switching element is connected between the sixth resistor and the first capacitor. The other end of the sixth resistor is connected to the power supply module, and the other end of the first capacitor is grounded.

7. The load drive circuit according to claim 2, characterized in that, The undervoltage protection circuit also includes a seventh resistor, which is connected between the anode of the first Zener diode and the first enable terminal of the second switching module.

8. The load drive circuit according to claim 5, characterized in that, The overvoltage protection circuit further includes a third diode, the anode of which is connected to the connection node between the second resistor and the second Zener diode, and the cathode of which is connected to the enable terminal of the third switching element.

9. The load drive circuit according to claim 8, characterized in that, The overvoltage protection circuit also includes an eighth resistor, one end of which is connected to the enable terminal of the third switching element, and the other end is connected to the cathode of the third diode.

10. The load drive circuit according to claim 9, characterized in that, The overcurrent protection circuit further includes a fourth diode, the anode of which is connected to the connection node between the electrical terminal of the first switching module and the third resistor, and the cathode of which is connected to the connection node between the eighth resistor and the cathode of the third diode.

11. The load drive circuit according to claim 1, characterized in that, It also includes a fifth diode, the anode of which is connected to the control signal output terminal of the main control circuit, and the cathode is connected to the enable terminal of the first switching module.

12. The load drive circuit according to claim 1, characterized in that, The first switching module includes a sixth switching element, the enable terminal of the sixth switching element serves as the enable terminal of the first switching module, and the electrical terminal of the sixth switching element serves as the electrical terminal of the first switching module.

13. The load drive circuit according to claim 12, characterized in that, The first switching module further includes a ninth resistor, one end of which is connected to the enable terminal of the sixth switching element, and the other end of which serves as the enable terminal of the first switching module and is connected to the control signal output terminal of the main control circuit.

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