Motor driving circuit, circuit board and electric tool

Abstract

The invention discloses a motor driving circuit, a circuit board and an electric tool, and relates to the technical field of electronic circuits. The circuit comprises a control module, a level conversion module, a buffer module, a driving module and an H-bridge module, the control module is connected with the level conversion module, the level conversion module is connected with the buffer module, the buffer module is connected with the driving module, and the driving module is connected with the H-bridge module; wherein the buffer module is used for transmitting a control signal to the driving module in a delayed manner; and the driving module is used for determining a driving voltage for the H-bridge module according to the driving signal and avoiding common-state conduction of the H-bridge module. Transmission of the control signal is delayed through the buffer module, and then the control signal is converted into the driving voltage for the H bridge module through the driving module according to the control signal, so that simultaneous conduction of an upper tube and a lower tube of a bridge arm on any side of an H bridge is effectively avoided, short circuit of a power supply is prevented, power transistors serving as the upper tube and the lower tube are protected, and the stability of the motor driving circuit is improved.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a motor drive circuit, circuit board and power tool. Background Technology

[0002] In the field of power tools, the drive control module is a core component, and its performance directly determines the operational stability, efficiency, and energy consumption of the power tool. Traditional drive control devices mostly use N-channel MOSFETs to construct DC motor drive circuits, which have poor stability when achieving bidirectional motor rotation, and are prone to the problem of simultaneous conduction of the upper and lower arms of the H-bridge MOSFETs (common mode conduction), leading to power short circuits, damage to power devices, and affecting the lifespan of the device. On the other hand, the low integration of the device is not conducive to product miniaturization. Summary of the Invention

[0003] To address the problems mentioned in the background section, this application provides the following technical solutions: In a first aspect, a motor drive circuit is provided, comprising: a control module, a level conversion module, a buffer module, a drive module, and an H-bridge module.

[0004] The control module is connected to the level conversion module, the level conversion module is connected to the buffer module, the buffer module is connected to the driver module, and the driver module is connected to the H-bridge module.

[0005] The control module is used to receive control signals for the motor and control the motor to rotate in the direction corresponding to the control signals.

[0006] The level conversion module is used to convert the control signal into the drive signal for the H-bridge module.

[0007] The buffer module is used to delay the transmission of control signals to the drive module.

[0008] The drive module is used to determine the drive voltage for the H-bridge module based on the drive signal, thereby preventing the H-bridge module from being turned on in common mode.

[0009] The H-bridge module is used to drive the motor connected to it.

[0010] In a second aspect, a circuit board is provided, including the motor drive circuit described in the first aspect.

[0011] Thirdly, an electric tool is provided, including the circuit board described in the second aspect.

[0012] This application describes a motor drive circuit, circuit board, and power tool. The control signal is delayed through a buffer module, and then converted into a drive voltage for the H-bridge module based on the control signal by the drive module. This effectively prevents the simultaneous conduction of the upper and lower transistors on either side of the H-bridge, preventing power short circuits, protecting the power transistors used as the upper and lower transistors, and improving the stability of the motor drive circuit. It can drive the motor to rotate bidirectionally according to the control signal. Precise motor speed regulation is achieved by using PWM control of the first and second square waves. The device has high conversion efficiency, a simplified circuit structure, and a small footprint. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of a motor drive circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of the level conversion module circuit provided in an embodiment of this application; Figure 3 This is a schematic diagram of a buffer module circuit provided in an embodiment of this application; Figure 4 This is a schematic diagram of another buffer module circuit provided in an embodiment of this application; Figure 5 This is a schematic diagram of the H-bridge module circuit provided in an embodiment of this application; Figure 6 This is a schematic diagram of the connection relationship of a driver module provided in an embodiment of this application; Figure 7 This is a schematic diagram of a driving module circuit provided in an embodiment of this application; Figure 8 This is another schematic diagram of the connection relationship of the driver modules provided in the embodiments of this application; Figure 9 This is a schematic diagram of another driving module circuit provided in an embodiment of this application; Figure 10 This is another schematic diagram of a driving module circuit provided in the embodiments of this application; Figure 11 This is a schematic diagram of the motor drive circuit provided in an embodiment of this application; Figure 12 This is a schematic diagram of another motor drive circuit module provided in an embodiment of this application; Figure 13This is a schematic diagram of the current detection module circuit provided in an embodiment of this application. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0016] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The numbers in the accompanying drawings are only used to distinguish individual functional parts or modules and do not indicate logical relationships between parts or modules. The terms “comprising,” “including,” or “including,” and similar terms mean that the element or object preceding the term encompasses the element or object listed following the term and its equivalents, without excluding other elements or objects. The terms “connected,” “linked,” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. “Above,” “below,” “left,” “right,” etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0017] The various embodiments according to this disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same reference numerals are assigned to components having substantially the same or similar structure and function, and repeated descriptions of them will be omitted.

[0018] To address the issue of common-mode conduction in the H-bridge of traditional power tool drive devices during operation, this application provides the following technical solution.

[0019] In some embodiments, such as Figure 1 As shown, a motor drive circuit includes: a control module 100, a level conversion module 200, a buffer module 300, a drive module 400, and an H-bridge module 500.

[0020] The control module 100 is connected to the level conversion module 200, the level conversion module 200 is connected to the buffer module 300, the buffer module 300 is connected to the drive module 400, and the drive module 400 is connected to the H-bridge module 500.

[0021] The control module 100 is used to receive control signals for the motor M and control the motor M to rotate in a direction corresponding to the control signals.

[0022] The level conversion module 200 is used to convert the control signal into a drive signal for the H-bridge module 500.

[0023] The buffer module 300 is used to delay the transmission of control signals to the drive module 400.

[0024] The drive module 400 is used to determine the drive voltage for the H-bridge module 500 based on the drive signal, so as to prevent the H-bridge module 500 from being turned on in common mode.

[0025] H-bridge module 500 is used to drive the motor M connected to it.

[0026] The motor drive circuit described in this application delays the transmission of control signals through a buffer module, and then converts the control signals into drive voltages for the H-bridge module through a drive module. This effectively prevents the simultaneous conduction of the upper and lower transistors on either side of the H-bridge arm, prevents power short circuits, protects the power transistors that serve as the upper and lower transistors, and improves the stability of the motor drive circuit.

[0027] Specifically, such as Figure 1 As shown, the control module 100 has: an external signal receiving port 100a, a first output port 100b of the control module, and a second output port 100c of the control module.

[0028] The level conversion module 200 has: a first input port 200a, a second input port 200b, a first output port 200c, and a second output port 200d.

[0029] The buffer module 300 has: a first input port 300a, a second input port 300b, a first output port 300c, and a second output port 400d.

[0030] The driver module 400 has a first input port 400a and a second input port 400b.

[0031] The H-bridge module 500 has: a first input port 500a, a second input port 500b, a third input port 500c, a fourth output port 500d, a first motor output port 500e, and a second motor output port 500f.

[0032] External signal receiving port 100a is used to receive control signals. The first output port 100b of the control module is connected to the first input port 200a of the level conversion module. The second output port 100c of the control module is connected to the second input port 200b of the level conversion module. The first output port 200c of the level conversion module is connected to the first input port 300a of the buffer module. The second output port 200d of the level conversion module is connected to the second input port 300b of the buffer module. The first output port 300c of the buffer module is connected to the first input port 400a of the drive module. The second output port 400d of the buffer module is connected to the second input port 400b of the drive module. The first input port 500a, the second input port 500b, the third input port 500c, and the fourth output port 500d of the H-bridge are connected to the drive module 400. The first motor output port 500e and the second motor output port 500f are used to connect to the two ports of the motor M, respectively.

[0033] Specifically, such as Figure 2 As shown, the level conversion module 200 includes: a first comparator 210, a second comparator 220, a first diode D1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6.

[0034] The non-inverting input of the first comparator 210 is connected to one end of the third resistor R3 and one end of the fourth resistor R4. The other end of the third resistor R3 serves as the first input port 200a of the level conversion module, and the other end of the fourth resistor R4 is grounded. The inverting input of the first comparator 210 is connected to the inverting input of the second comparator 220, the cathode of the first diode D1, one end of the first resistor R1, and one end of the second resistor R2. The other end of the first resistor R1 is connected to the first operating voltage V. CC1 The other end of the second resistor R2 is connected to the anode of the first diode D1 and then grounded. The non-inverting input of the second comparator 220 is connected to one end of the fifth resistor R5 and one end of the sixth resistor R6. The other end of the fifth resistor R5 serves as the second input port 200b of the level conversion module, and the other end of the sixth resistor R6 is grounded. The output of the first comparator 210 serves as the first output port 200c of the level conversion module, and the output of the second comparator 220 serves as the second output port 200d of the level conversion module.

[0035] First operating voltage V CC1 And the second operating voltage V, which will be discussed below.CC2 and the third working voltage V CC3 This is used to provide the voltage necessary for the normal operation of the electronic components within the corresponding module. This application does not limit the first operating voltage V. CC1 For, the second working voltage V CC2 And the specific value of the third operating voltage. Those skilled in the art can select the specific value of the above operating voltage according to the actual situation to enable the circuit to function normally. Schematic, the first operating voltage V... CC1 The second operating voltage is 5V. CC2 It is 12V, the third working voltage V CC3 It is 24V.

[0036] To save space in the circuit, the first and second comparators can be multi-channel comparator chips to compare multiple sets of voltages. Optionally, the multi-channel comparator chip can be the KF347 (FAIRCHILD).

[0037] First operating voltage V CC1 A reference voltage is obtained by voltage division using the first resistor R1 and the second resistor R2, and is connected to the inverting input terminals of the first comparator 210 and the second comparator 220 as a voltage reference. The first diode D1 is a Zener diode. The control signal is input through the first input port 200a of the level conversion module, and after voltage division by the third resistor R3 and the fourth resistor R4, it is input to the non-inverting input terminal of the first comparator 210. The first comparator 210 generates a first square wave signal based on the input voltages at its non-inverting and inverting input terminals, and outputs the first square wave signal through the first output port 200c of the level conversion module.

[0038] A signal, generated based on the control signal and complementary in phase to the control signal, is input through the second input port 200b of the level conversion module. After being divided by the fifth resistor R5 and the sixth resistor R6, it is input to the non-inverting input of the second comparator 220. The second comparator 220 generates a second square wave signal, complementary in phase to the first square wave signal, based on the input voltages at its non-inverting and inverting inputs, and outputs the second square wave signal through the second output port 200d of the level conversion module.

[0039] The first square wave signal and the second square wave signal are used as driving signals. By modulating the duty cycle of the first square wave signal and the second square wave signal, the motor speed can be controlled.

[0040] In some embodiments, such as Figure 3 As shown, the buffer module 300 includes: a first inverter 310, a second inverter 320, a third inverter 330, a fourth inverter 340, a second diode D2, a third diode D3, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and a tenth resistor R10. 10The first capacitor C1 and the second capacitor C2.

[0041] The input terminal of the first inverter 310 serves as the first input port 300a of the buffer module. The output terminal of the first inverter 310 is connected to one end of the seventh resistor R7, one end of the eighth resistor R8, and the anode of the second diode D2. The other end of the eighth resistor R8 is grounded. The cathode of the second diode D2 is connected to the other end of the seventh resistor R7, one end of the first capacitor C1, and the input terminal of the second inverter 320. The other end of the first capacitor C1 is grounded. The output terminal of the second inverter 320 serves as the first output port 300c of the buffer module.

[0042] The input terminal of the third inverter 330 serves as the second input port 300b of the buffer module. The output terminal of the third inverter 330 is connected to one end of the ninth resistor R9 and the tenth resistor R 10 One end of the diode is connected to the anode of the third diode D3, and the tenth resistor R is connected to the anode of the third diode D3. 10 The other end is grounded. The cathode of the third diode D3 is connected to the other end of the ninth resistor R9, one end of the second capacitor C2, and the input of the fourth inverter 340. The other end of the second capacitor C2 is grounded. The output of the fourth inverter 340 serves as the second output port 400d of the buffer module.

[0043] The first square wave signal input from the first input port 300a of the buffer module is delayed and output in phase from the first output port 300c of the buffer module; the second square wave signal input from the second input port 300b of the buffer module is delayed and output in phase from the second output port 300d of the buffer module. This signal delay prevents the H-bridge module from engaging in common mode.

[0044] In other embodiments, such as Figure 4 As shown, the buffer module 300 includes: a fifth inverter 350, a sixth inverter 360, a seventh inverter 370, an eighth inverter 380, a fourth diode D4, a fifth diode D5, and an eleventh resistor R. 11 and the twelfth resistor R 12 .

[0045] The input terminal of the fifth inverter 350 serves as the first input port 300a of the buffer module. The output terminal of the fifth inverter 350 is connected to the cathode of the fourth diode D4 and the eleventh resistor R. 11 One end of the diode is connected to the control module 100 (not shown in the figure) to transmit a signal with the opposite phase to the signal received at the input of the fifth inverter 350. When the output of the fifth inverter 350 is high, a high-potential-to-ground branch can be formed through the pin of the connected control module 100, saving the need to construct a high-potential-to-ground current branch using discrete components. The anode of the fourth diode D4 is connected to the eleventh resistor R.11 The other end of the capacitor is connected to one end of the third capacitor C3 and the input of the sixth inverter 360. The other end of the third capacitor C3 is grounded. The output of the sixth inverter 360 serves as the first output port 300c of the buffer module.

[0046] The input terminal of the seventh inverter 370 serves as the second input port 300b of the buffer module. The output terminal of the seventh inverter 370 is connected to the cathode of the fifth diode D5 and the twelfth resistor R. 12 One end of the diode is connected to the control module 100 (not shown in the figure) to transmit a signal with the opposite phase to the signal received at the input of the seventh inverter 370. When the output of the seventh inverter 370 is high, a high-potential-to-ground branch can be formed through the pin of the connected control module 100, saving the need to construct a high-potential-to-ground current branch using discrete components. The anode of the fifth diode D5 is connected to the twelfth resistor R. 12 The other end of the fourth capacitor C4 is connected to the input of the eighth inverter 380. The other end of the fourth capacitor C4 is grounded. The output of the eighth inverter 380 serves as the second output port 400d of the buffer module.

[0047] like Figure 5 As shown, the H-bridge module 500 includes: a first transistor T1, a second transistor T2, a third transistor T3, a fourth transistor T4, and a thirteenth resistor R. 13 .

[0048] The gate of the first transistor T1 serves as the first input port 500a of the H-bridge. The source of the first transistor T1 is connected to the source of the third transistor T3 and then connected to the second operating voltage V. CC2 The drain of the first transistor T1 is connected to the drain of the second transistor T2 to serve as the first motor output port 500e. The gate of the second transistor T2 serves as the second input port 500b of the H-bridge. The source of the second transistor T2 is connected to the source of the fourth transistor T4 and then to the thirteenth resistor R. 13 One end is connected to the thirteenth resistor R. 13 The other end is grounded. The gate of the third transistor T3 serves as the third input port 500c of the H-bridge. The drain of the third transistor T3 is connected to the drain of the fourth transistor T4 to serve as the second motor output port 500f. The gate of the fourth transistor T4 serves as the fourth output port 500d of the H-bridge.

[0049] Among them, the first transistor T1 and the third transistor T3 are P-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors); the second transistor T2 and the fourth transistor T4 are N-channel MOSFETs.

[0050] When motor M is operating normally, the first transistor T1 and the fourth transistor T4 in the H-bridge module 500 are simultaneously turned on. When they are on, the second transistor T2 and the third transistor T3 are turned off, causing the motor rotor to rotate in the first direction. When the second transistor T2 and the third transistor T3 are simultaneously turned on, the first transistor T1 and the fourth transistor T4 are simultaneously turned off, causing the motor rotor to rotate in the second direction. The first and second directions of rotation are opposite. The load current flows through the thirteenth resistor R. 13 .

[0051] In some embodiments, such as Figure 6 As shown, the driver module 400 also has: a first output port 400c, a second output port 400d, a third output port 400e, and a fourth output port 400f.

[0052] The first output port 400c of the driver module is connected to the first input port 500a of the H-bridge, the second output port 400d of the driver module is connected to the second input port 500b of the H-bridge, the third output port 400e of the driver module is connected to the third input port 500c of the H-bridge, and the fourth output port 400f of the driver module is connected to the fourth output port 500d of the H-bridge.

[0053] Specifically, such as Figure 7 As shown, the drive module 400 includes: a sixth diode D6, a seventh diode D7, an eighth diode D8, a ninth diode D9, and a fourteenth resistor R. 14 The fifteenth resistor R 15 The sixteenth resistor R 16 The seventeenth resistor R 17 The eighteenth resistor R 18 and the nineteenth resistor R 19 .

[0054] The fourteenth resistor R 14 One end serves as the first input port 400a of the driver module, and the fourteenth resistor R 14 The other end is connected to the anode of the sixth diode D6 and the fifteenth resistor R. 15 One end, the cathode of the seventh diode D7, and the sixteenth resistor R 16 One end is connected, and the cathode of the sixth diode D6 is connected to the fifteenth resistor R. 15 The other end, after being connected, serves as the first output port 400c of the drive module. The anode of the seventh diode D7 is connected to the sixteenth resistor R. 16 The other end is connected and serves as the second output port 400d of the driver module.

[0055] The seventeenth resistor R 17One end serves as the second input port 400b of the driver module, and the seventeenth resistor R 17 The other end is connected to the anode of the eighth diode D8 and the eighteenth resistor R. 18 One end, the cathode of the ninth diode D9, and the nineteenth resistor R 19 One end is connected, and the cathode of the eighth diode D8 is connected to the eighteenth resistor R. 18 The other end, after being connected, serves as the third output port 400e of the drive module. The anode of the ninth diode D2 is connected to the nineteenth resistor R. 19 The other end is connected and serves as the fourth output port 400f of the driver module.

[0056] When the first input port 400a of the driver module receives a low potential, it outputs a low potential at the first output port 400c and the second output port 400d of the driver module, thereby driving the first transistor T1 to turn on through the first input port 500a of the H-bridge and driving the second transistor T2 to turn off through the second input port 500b of the H-bridge. When the first input port 400a of the driver module receives a high potential, it outputs a high potential at the first output port 400c and the second output port 400d of the driver module, thereby driving the first transistor T1 to turn off through the first input port 500a of the H-bridge and driving the second transistor T2 to turn on through the second input port 500b of the H-bridge.

[0057] The potential received by the second input port 400b of the drive module is output at the third output port 400e and the fourth output port 400f of the drive module. This is similar to the situation described above where the potential received by the first input port 400a of the drive module is output at the first output port 400c and the second output port 400d of the drive module, and will not be repeated here.

[0058] Using the sixth diode D6, the seventh diode D7, the eighth diode D8, and the ninth diode D9 can improve the circuit's response speed.

[0059] In other embodiments, such as Figure 8 As shown, the driver module 400 also has: a first output port 400c and a second output port 400d.

[0060] The first output port 400c of the driver module is connected to the first input port 500a and the second input port 500b of the H-bridge, and the second output port 400d of the driver module is connected to the third input port 500c and the fourth output port 500d of the H-bridge.

[0061] As another implementation of the driver module 400, such as Figure 9As shown, the drive module 400 includes: a first transistor Q1, a second transistor Q2, and a twentieth resistor R. 20 The twenty-first resistor R 21 The twenty-second resistor R 22 The twenty-third resistor R 23 The twenty-fourth resistor R 24 And the twenty-fifth resistor R 25 .

[0062] The twentieth resistor R 20 One end serves as the first input port 400a of the driver module, and the twentieth resistor R 20 The other end is connected to the base of the first transistor Q1, and the collector of the first transistor Q1 is connected to the twenty-first resistor R. 21 One end and the twenty-second resistor R 22 One end is connected and serves as the first output port 400c of the driver module, and the twenty-first resistor R 21 The other end is connected to the third working voltage V CC3 The emitter of the first transistor Q1 is connected to the twenty-second resistor R. 22 The other end is connected to ground.

[0063] The twenty-third resistor R 23 One end serves as the second input port 400b of the driver module, and the twenty-third resistor R 23 The other end is connected to the base of the second transistor Q2, and the collector of the second transistor Q2 is connected to the twenty-fourth resistor R. 24 One end and the twenty-fifth resistor R 25 One end is connected and serves as the second output port 400d of the driver module, and the twenty-fourth resistor R 24 The other end is connected to the third working voltage V CC3 The emitter of the second transistor Q2 is connected to the twenty-fifth resistor R. 25 The other end is connected to ground.

[0064] In this embodiment, both the first transistor Q1 and the second transistor Q2 are NPN transistors. In this embodiment, the first transistor Q1 and the second transistor Q2 receive signals through their respective bases and output drive voltages at their respective collectors.

[0065] In some other embodiments, such as Figure 10 As shown, the drive module 400 includes: a third transistor Q3, a fourth transistor Q4, and a twenty-sixth resistor R. 26 The twenty-seventh resistor R 27 The twenty-eighth resistor R 28 And the twenty-ninth resistor R 29 .

[0066] The base of the third transistor Q3 serves as the first input port 400a of the driver module, and the collector of the third transistor Q3 is connected to the twenty-sixth resistor R. 26 One end is connected to the twenty-sixth resistor R. 26 The other end is connected to the twenty-seventh resistor R 27 One end is connected and serves as the first output port 400c of the driver module, and the twenty-seventh resistor R 27 The other end is connected to the third working voltage V CC3 The emitter of the third transistor Q3 is grounded.

[0067] The base of the fourth transistor Q4 serves as the second input port 400b of the driver module, and the collector of the fourth transistor Q4 is connected to the twenty-eighth resistor R. 28 One end is connected to the twenty-eighth resistor R. 28 The other end is connected to the twenty-ninth resistor R 29 One end is connected and serves as the second output port 400d of the driver module, and the twenty-ninth resistor R 29 The other end is connected to the third working voltage V CC3 The emitter of the fourth transistor Q4 is grounded.

[0068] In this embodiment, both transistor Q3 (third transistor) and transistor Q4 (fourth transistor) are NPN transistors. Transistor Q3 receives the signal through its base and through the twenty-sixth resistor R. 26 and the twenty-seventh resistor R 27 The output drive voltage is located at the connection point; the fourth transistor Q4 receives the signal through its base and through the twenty-eighth resistor R. 28 And the twenty-ninth resistor R 29 The output drive voltage is located at the connection point.

[0069] Second operating voltage V CC2 It is 12V, the third working voltage V CC3 With a voltage of 24V, the twenty-sixth resistor R 26 The resistance value is the same as that of the twenty-seventh resistor R. 27 The resistance values ​​are set to be equal, and the twenty-eighth resistor R is... 28 The resistance value and the twenty-ninth resistor R 29 The resistance values ​​are set to be equal, which enables the H-bridge module to drive normally. This application specifies the twenty-sixth resistor R... 26 The twenty-seventh resistor R 27 The twenty-eighth resistor R 28 And the twenty-ninth resistor R 29 The specific value of the resistance is not limited.

[0070] Figure 11 A motor drive circuit diagram according to an embodiment of this application is shown.

[0071] Preferably, such as Figure 12 As shown, the motor drive circuit also includes a current detection module 600.

[0072] The current detection module 600 has: a first port 600a and a second port 600b.

[0073] The control module 100 also has an overcurrent detection port 100d.

[0074] The first port 600a of the current detection module is connected to the thirteenth resistor R in the H-bridge module 500. 13 One end is connected (not shown in the figure) to collect the flow through the thirteenth resistor R. 13 The load current is measured, and the second port 600b of the current detection module is connected to the overcurrent detection port 100d.

[0075] The second port 600b of the current detection module transmits the load current detection result to the overcurrent detection port 100d. When the load current exceeds the preset current value, the control module 100 sets the output signals of the first output port 100b and the second output port 100c of the control module to low level at the same time, so that the motor M stops working.

[0076] Specifically, such as Figure 13 As shown, the current detection module 600 includes: an operational amplifier OP, a thirtieth resistor R 30 The thirty-first resistor R 31 The thirty-second resistor R 32 The thirty-third resistor R 33 The thirty-fourth resistor R 34 The fifth capacitor C5, the sixth capacitor C6, and the seventh capacitor C7.

[0077] The non-inverting input of the operational amplifier OP is connected to one end of the fifth capacitor C5 and the thirtieth resistor R. 30 One end and the thirty-first resistor R 31 One end is connected to the inverting input of the operational amplifier OP and the thirty-second resistor R. 32 One end, the thirty-third resistor R 33 One end of the capacitor is connected to one end of the sixth capacitor C6, and the thirtieth resistor R is connected to the other end of the capacitor C6. 30 The other end is connected to the first working voltage V CC1 The thirty-first resistor R 31 The other end serves as the first port 600a of the current detection module, and the other end of the fifth capacitor C5 is connected to the thirty-second resistor R. 32 The other end is connected to ground, and the output of the operational amplifier OP is connected to the thirty-third resistor R. 33 The other end, the other end of the sixth capacitor C6, and the thirty-fourth resistor R34 One end is connected to the 34th resistor R. 34 The other end is connected to one end of the seventh capacitor C7 and serves as the second port 600b of the current detection module. The other end of the seventh capacitor C7 is grounded.

[0078] The current received by the current detection module at its first port 600a is converted into a voltage signal and output by the second port 600b of the current detection module. The control module 100 then compares the voltages to determine whether the load is overcurrent. If an overcurrent occurs, the control module M stops working.

[0079] In other embodiments, a circuit board includes the motor drive circuit described above.

[0080] In other embodiments, a power tool includes the circuit board described above.

[0081] This application describes a motor drive circuit, circuit board, and power tool. The control signal is delayed through a buffer module, and then converted into a drive voltage for the H-bridge module based on the control signal by the drive module. This effectively prevents simultaneous conduction of the upper and lower transistors on either side of the H-bridge, preventing power short circuits, protecting the power transistors used as the upper and lower transistors, and improving the stability of the motor drive circuit. It can drive the motor to rotate bidirectionally according to the control signal. Precise motor speed regulation is achieved by using PWM control of the first and second square wave signals. The device has high conversion efficiency, a simplified circuit structure, and a small footprint.

[0082] All of the above-mentioned optional technical solutions can be combined in any way to form the optional embodiments of this application, and will not be described in detail here.

[0083] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An electric motor drive circuit, characterized by The application relates to a motor control system, which comprises a control module (100), a level conversion module (200), a buffer module (300), a driving module (400) and an H-bridge module (500). The control module (100) is connected with the level conversion module (200), the level conversion module (200) is connected with the buffer module (300), the buffer module (300) is connected with the driving module (400), and the driving module (400) is connected with the H-bridge module (500). The control module (100) is used for receiving a control signal of a motor (M) and controlling the motor (M) to rotate in a direction corresponding to the control signal according to the control signal. The level conversion module (200) is used for converting the control signal to obtain a driving signal of the H-bridge module (500). The buffer module (300) is used for delaying transmission of the control signal to the driving module (400). The driving module (400) is used for determining a driving voltage of the H-bridge module (500) according to the driving signal, so as to avoid common-state conduction of the H-bridge module (500). The H-bridge module (500) is used for driving the motor (M) connected therewith. The control module (100) has an external signal receiving port (100a), a control module first output port (100b) and a control module second output port (100c).

2. The motor drive circuit of claim 1, wherein, The level conversion module (200) has a level conversion module first input port (200a), a level conversion module second input port (200b), a level conversion module first output port (200c) and a level conversion module second output port (200d). The buffer module (300) has a buffer module first input port (300a), a buffer module second input port (300b), a buffer module first output port (300c) and a buffer module second output port (400d). The driving module (400) has a driving module first input port (400a) and a driving module second input port (400b). The H-bridge module (500) has an H-bridge first input port (500a), an H-bridge second input port (500b), an H-bridge third input port (500c), an H-bridge fourth output port (500d), a first motor output port (500e) and a second motor output port (500f). ​ The external signal receiving port (100a) is used for receiving the control signal, the control module first output port (100b) is connected with the level conversion module first input port (200a), the control module second output port (100c) is connected with the level conversion module second input port (200b), the level conversion module first output port (200c) is connected with the buffer module first input port (300a), the level conversion module second output port (200d) is connected with the buffer module second input port (300b), the buffer module first output port (300c) is connected with the drive module first input port (400a), the buffer module second output port (400d) is connected with the drive module second input port (400b), the H bridge first input port (500a), the H bridge second input port (500b), the H bridge third input port (500c) and the H bridge fourth output port (500d) are connected with the drive module (400), and the first motor output port (500e) and the second motor output port (500f) are used for being connected with two ports of the motor (M) respectively.

3. The motor drive circuit of claim 2, wherein, The level conversion module (200) comprises: a first comparator (210), a second comparator (220), a first diode (D1), a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5) and a sixth resistor (R6); The non-inverting input terminal of the first comparator (210) is connected with one end of the third resistor (R3) and one end of the fourth resistor (R4), the other end of the third resistor (R3) is the first input port (200a) of the level conversion module, the other end of the fourth resistor (R4) is grounded, the inverting input terminal of the first comparator (210) is connected with the inverting input terminal of the second comparator (220), the cathode of the first diode (D1), one end of the first resistor (R1) and one end of the second resistor (R2), the other end of the first resistor (R1) is connected with the first working voltage (V CC1 ), the other end of the second resistor (R2) is connected with the anode of the first diode (D1) and then grounded, the non-inverting input terminal of the second comparator (220) is connected with one end of the fifth resistor (R5) and one end of the sixth resistor (R6), the other end of the fifth resistor (R5) is the second input port (200b) of the level conversion module, the other end of the sixth resistor (R6) is grounded, the output terminal of the first comparator (210) is the first output port (200c) of the level conversion module, and the output terminal of the second comparator (220) is the second output port (200d) of the level conversion module.

4. The motor drive circuit of claim 2, wherein, The buffer module (300) comprises a first inverter (310), a second inverter (320), a third inverter (330), a fourth inverter (340), a second diode (D2), a third diode (D3), a seventh resistor (R7), an eighth resistor (R8), a ninth resistor (R9), a tenth resistor (R 10 ), a first capacitor (C1), and a second capacitor (C2). The input end of the first inverter (310) is used as the buffer module first input port (300a), the output end of the first inverter (310) is connected with one end of the seventh resistor (R7), one end of the eighth resistor (R8) and the anode of the second diode (D2), the other end of the eighth resistor (R8) is grounded, the cathode of the second diode (D2) is connected with the other end of the seventh resistor (R7), one end of the first capacitor (C1) and the input end of the second inverter (320), the other end of the first capacitor (C1) is grounded, and the output end of the second inverter (320) is used as the buffer module first output port (300c); The input end of the third inverter (330) is the second input port (300b) of the buffer module, the output end of the third inverter (330) is connected with one end of the ninth resistor (R9), one end of the tenth resistor (R 10 ), and the anode of the third diode (D3), the other end of the tenth resistor (R 10 ) is grounded, the cathode of the third diode (D3) is connected with the other end of the ninth resistor (R9), one end of the second capacitor (C2), and the input end of the fourth inverter (340), the other end of the second capacitor (C2) is grounded, and the output end of the fourth inverter (340) is the second output port (400d) of the buffer module.

5. The motor drive circuit of claim 2, wherein, The buffer module (300) comprises a fifth inverter (350), a sixth inverter (360), a seventh inverter (370), an eighth inverter (380), a fourth diode (D4), a fifth diode (D5), an eleventh resistor (R 11 ) and a twelfth resistor (R 12 ). The input end of the fifth inverter (350) is the first input port (300a) of the buffer module, the output end of the fifth inverter (350) is connected with the cathode of the fourth diode (D4) and one end of the eleventh resistor (R 11 ), and then connected with the control module (100) for transmitting a signal opposite in phase to the signal received by the input end of the fifth inverter (350); the anode of the fourth diode (D4) is connected with the other end of the eleventh resistor (R 11 ), one end of the third capacitor (C3) and the input end of the sixth inverter (360), the other end of the third capacitor (C3) is grounded, and the output end of the sixth inverter (360) is the first output port (300c) of the buffer module; The input end of the seventh inverter (370) is the second input port (300b) of the buffer module, the output end of the seventh inverter (370) is connected with the cathode of the fifth diode (D5) and one end of the twelfth resistor (R 12 ), and then connected with the control module (100) for transmitting a signal opposite to the phase of the signal received by the input end of the seventh inverter (370), the anode of the fifth diode (D5) is connected with the other end of the twelfth resistor (R 12 ), one end of the fourth capacitor (C4) and the input end of the eighth inverter (380), the other end of the fourth capacitor (C4) is grounded, and the output end of the eighth inverter (380) is the second output port (400d) of the buffer module.

6. The motor drive circuit of claim 2, wherein, The H-bridge module (500) comprises a first transistor (T1), a second transistor (T2), a third transistor (T3), a fourth transistor (T4), and a thirteenth resistor (R 13 ) The gate of the first transistor (T1) is the first input port (500a) of the H-bridge, the source of the first transistor (T1) is connected with the source of the third transistor (T3) and then connected with the second working voltage (V CC2 ), the drain of the first transistor (T1) is connected with the drain of the second transistor (T2) and then is the first motor output port (500e), the gate of the second transistor (T2) is the second input port (500b) of the H-bridge, the source of the second transistor (T2) is connected with the source of the fourth transistor (T4) and then is connected with one end of the thirteenth resistor (R 13 ), the other end of the thirteenth resistor (R 13 ) is grounded, the gate of the third transistor (T3) is the third input port (500c) of the H-bridge, the drain of the third transistor (T3) is connected with the drain of the fourth transistor (T4) and then is the second motor output port (500f), and the gate of the fourth transistor (T4) is the fourth output port (500d) of the H-bridge.

7. The motor drive circuit of claim 2, wherein, The drive module (400) further has: a drive module first output port (400c), a drive module second output port (400d), a drive module third output port (400e) and a drive module fourth output port (400f); The drive module first output port (400c) is connected with the H bridge first input port (500a), the drive module second output port (400d) is connected with the H bridge second input port (500b), the drive module third output port (400e) is connected with the H bridge third input port (500c), and the drive module fourth output port (400f) is connected with the H bridge fourth output port (500d).

8. The motor drive circuit of claim 7, wherein, The driving module (400) comprises a sixth diode (D6), a seventh diode (D7), an eighth diode (D8), a ninth diode (D9), a fourteenth resistor (R 14 ), a fifteenth resistor (R 15 ), a sixteenth resistor (R 16 ), a seventeenth resistor (R 17 ), an eighteenth resistor (R 18 ) and a nineteenth resistor (R 19 ). one end of the fourteenth resistor (R 14 ) as the first input port (400a) of the driving module, the other end of the fourteenth resistor (R 14 ) is connected with the anode of the sixth diode (D6), one end of the fifteenth resistor (R 15 ), the cathode of the seventh diode (D7) and one end of the sixteenth resistor (R 16 ), the cathode of the sixth diode (D6) is connected with the other end of the fifteenth resistor (R 15 ) and then as the first output port (400c) of the driving module, the anode of the seventh diode (D7) is connected with the other end of the sixteenth resistor (R 16 ) and then as the second output port (400d) of the driving module; one end of the seventeenth resistor (R 17 ) as the second input port (400b) of the driving module, the other end of the seventeenth resistor (R 17 ) is connected with the anode of the eighth diode (D8), one end of the eighteenth resistor (R 18 ), the cathode of the ninth diode (D9) and one end of the nineteenth resistor (R 19 ), the cathode of the eighth diode (D8) is connected with the other end of the eighteenth resistor (R 18 ) and then as the third output port (400e) of the driving module, the anode of the ninth diode (D2) is connected with the other end of the nineteenth resistor (R 19 ) and then as the fourth output port (400f) of the driving module.

9. The motor drive circuit of claim 2, wherein, The drive module (400) further has a drive module first output port (400c) and a drive module second output port (400d); The drive module first output port (400c) is connected with the H-bridge first input port (500a) and the H-bridge second input port (500b), and the drive module second output port (400d) is connected with the H-bridge third input port (500c) and the H-bridge fourth output port (500d).

10. The motor drive circuit of claim 9, wherein, The driving module (400) comprises a first triode (Q1), a second triode (Q2), a twentieth resistor (R 20 ), a twenty-first resistor (R 21 ), a twenty-second resistor (R 22 ), a twenty-third resistor (R 23 ), a twenty-fourth resistor (R 24 ) and a twenty-fifth resistor (R 25 ). one end of the twentieth resistor (R 20 ) as the first input port (400a) of the driving module, the other end of the twentieth resistor (R 20 ) is connected with the base of the first triode (Q1), the collector of the first triode (Q1) is connected with one end of the twenty-first resistor (R 21 ) and one end of the twenty-second resistor (R 22 ), and then the first output port (400c) of the driving module, the other end of the twenty-first resistor (R 21 ) is connected with the third working voltage (V CC3 ), and the emitter of the first triode (Q1) is connected with the other end of the twenty-second resistor (R 22 ) and then grounded; one end of the twenty-third resistor (R 23 ) is the second input port (400b) of the driving module, the other end of the twenty-third resistor (R 23 ) is connected with the base of the second triode (Q2), the collector of the second triode (Q2) is connected with one end of the twenty-fourth resistor (R 24 ) and one end of the twenty-fifth resistor (R 25 ), and then the second output port (400d) of the driving module, the other end of the twenty-fourth resistor (R 24 ) is connected with the third working voltage (V CC3 ), and the emitter of the second triode (Q2) is connected with the other end of the twenty-fifth resistor (R 25 ) and then grounded.

11. The motor drive circuit of claim 9, wherein, The driving module (400) comprises a third transistor (Q3), a fourth transistor (Q4), a twenty-sixth resistor (R 26 ), a twenty-seventh resistor (R 27 ), a twenty-eighth resistor (R 28 ) and a twenty-ninth resistor (R 29 ). The base of the third triode (Q3) is the first input port (400a) of the driving module, the collector of the third triode (Q3) is connected with one end of the twenty-sixth resistor (R 26 ), the other end of the twenty-sixth resistor (R 26 ) is connected with one end of the twenty-seventh resistor (R 27 ) and then is the first output port (400c) of the driving module, the other end of the twenty-seventh resistor (R 27 ) is connected with the third working voltage (V CC3 ), and the emitter of the third triode (Q3) is grounded. The base of the fourth triode (Q4) is the second input port (400b) of the driving module, one end of the twenty-eighth resistor (R 28 ) is connected with the collector of the fourth triode (Q4), the other end of the twenty-eighth resistor (R 28 ) is connected with one end of the twenty-ninth resistor (R 29 ) and then is the second output port (400d) of the driving module, the other end of the twenty-ninth resistor (R 29 ) is connected with the third working voltage (V CC3 ), and the emitter of the fourth triode (Q4) is grounded.

12. The motor drive circuit of claim 1, wherein, The motor drive circuit further comprises a current detection module (600); The current detection module (600) has a current detection module first port (600a) and a current detection module second port (600b); The control module (100) further has an overcurrent detection port (100d). The first port (600a) of the current detection module is connected with one end of the thirteenth resistor (R 13 ) in the H-bridge module (500), and the second port (600b) of the current detection module is connected with the overcurrent detection port (100d).

13. The motor drive circuit of claim 12, wherein, The current detection module (600) comprises an operational amplifier (OP), a thirtieth resistor (R 30 ), a thirty-first resistor (R 31 ), a thirty-second resistor (R 32 ), a thirty-third resistor (R 33 ), a thirty-fourth resistor (R 34 ), a fifth capacitor (C5), a sixth capacitor (C6), and a seventh capacitor (C7). An in-phase input end of the operational amplifier (OP) is connected with one end of the fifth capacitor (C5), one end of the thirtieth resistor (R 30 ) and one end of the thirty-first resistor (R 31 ), an inverse input end of the operational amplifier (OP) is connected with one end of the thirty-second resistor (R 32 ), one end of the thirty-third resistor (R 33 ) and one end of the sixth capacitor (C6), the other end of the thirtieth resistor (R 30 ) is connected with a first working voltage (V CC1 ), the other end of the thirty-first resistor (R 31 ) is used as a first port (600a) of the current detection module, the other end of the fifth capacitor (C5) is connected with the other end of the thirty-second resistor (R 32 ) and then grounded, the output end of the operational amplifier (OP) is connected with the other end of the thirty-third resistor (R 33 ), the other end of the sixth capacitor (C6) and one end of the thirty-fourth resistor (R 34 ), the other end of the thirty-fourth resistor (R 34 ) is connected with one end of the seventh capacitor (C7) and then used as a second port (600b) of the current detection module, and the other end of the seventh capacitor (C7) is grounded.

14. A circuit board, characterized by The motor drive circuit comprises the circuit board.

15. An electric power tool characterized by comprising: The circuit board comprises the motor drive circuit.

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