A control circuit and control signal for a brushed motor

Abstract

The utility model discloses a control circuit and control signal of brush motor relates to circuit technical field, include: the sum of first high level signal and second low level signal pulse width is equal to the sum of second low level signal and second high level signal pulse width, the pulse width of first low level signal is greater than the pulse width of second high level signal, and when first low level signal has outputed first short -circuit consumption time, second high level signal starts output, when second high level signal output ends and first low level signal has outputed second short -circuit consumption time, first high level signal starts output. The utility model discloses a method for short -circuit of MOS tube, forms big current in loop, converts electric energy into heat energy and consumes, converts electric energy into heat energy and releases, thereby eliminates the power bus voltage peak that forms in switching process.

Description

Technical Field

[0001] This utility model relates to the field of circuit technology, specifically to a control circuit and control signal for a brushed motor. Background Technology

[0002] Please see Figure 1 , Figure 1 This is a typical DC brushed motor drive circuit (i.e., a typical H-bridge circuit). The DC brushed motor drive circuit consists of four N-type MOSFETs forming an H-bridge circuit. A control circuit constitutes the entire DC brushed motor drive circuit. The H-bridge part of the circuit is powered by a single power supply (powered between V+ and GND). The control circuit has two input signals (IN1 and IN2), which are complementary and symmetrical. The two outputs of this DC brushed motor drive circuit are connected to the two ends of the DC motor respectively.

[0003] Conventional control methods can easily cause voltage spikes on the power bus during the rotation of a brushed DC motor, which can lead to overvoltage breakdown and damage to the MOSFETs in the H-bridge circuit in severe cases. Therefore, it is necessary to improve the control circuit of the brushed motor. Utility Model Content

[0004] In view of this, the present invention provides a control circuit and control signal for a brushed motor, thereby solving the problem in the prior art that the power supply bus voltage is prone to spikes during the rotation of a DC brushed motor, which can lead to overvoltage breakdown and damage of the MOS transistors in the H-bridge circuit in severe cases.

[0005] According to a first aspect, embodiments of the present invention provide a control circuit and control signal for a brushed motor, including:

[0006] Control circuit, H-bridge circuit, and motor;

[0007] The motor is electrically connected to the H-bridge circuit. The two outputs of the H-bridge circuit are electrically connected to the positive and negative terminals of the motor M, respectively. The H-bridge circuit is connected between the power supply terminal and ground.

[0008] The control circuit has a first input terminal IN1, a second input terminal IN2, a first output terminal HO1, a second output terminal LO1, a third output terminal HO2, and a fourth output terminal LO2. The first input terminal IN1 is electrically connected to the first output terminal HO1 and the second output terminal LO1, and the second input terminal IN2 is electrically connected to the third output terminal HO2 and the fourth output terminal LO2. The first output terminal HO1, the second output terminal LO1, the third output terminal HO2, and the fourth output terminal LO2 are respectively electrically connected to the first MOSFET M1, the second MOSFET M2, the third MOSFET M3, and the fourth MOSFET M4 in the H-bridge circuit.

[0009] The first input terminal IN1 is used to receive the first input signal, and the second input terminal IN2 is used to receive the second input signal. The first input signal consists of several segments of cyclically set first high-level signals and second low-level signals. The second input signal consists of several segments of cyclically set second low-level signals and second high-level signals. The sum of the pulse widths of the first high-level signals and the second low-level signals is equal to the sum of the pulse widths of the second low-level signals and the second high-level signals. The pulse width of the first low-level signal is greater than the pulse width of the second high-level signal. When the first low-level signal has been output for the first short-circuit consumption time, the second high-level signal starts to be output. When the second high-level signal output ends and the first low-level signal has been output for the second short-circuit consumption time, the first high-level signal starts to be output.

[0010] When the first input terminal IN1 receives a first high-level signal, the first output terminal HO1 and the second output terminal LO1 are set to high level and low level respectively. When the first input terminal IN1 receives a first low-level signal, the first output terminal HO1 and the second output terminal LO1 are set to low level and high level respectively.

[0011] When the second input terminal IN2 receives a second high-level signal, the third output terminal HO2 and the fourth output terminal LO2 are set to high level and low level, respectively. When the second input terminal IN2 receives a second low-level signal, the third output terminal HO2 and the fourth output terminal LO2 are set to low level and high level, respectively.

[0012] In conjunction with the first aspect, in the first embodiment of the first aspect, the pulse width of the second low-level signal is equal to the pulse width of the second high-level signal.

[0013] In conjunction with the first aspect, in the second embodiment of the first aspect, the pulse width of the second low-level signal is not equal to the pulse width of the second high-level signal.

[0014] In conjunction with the first aspect, in the third embodiment of the first aspect, the pulse width of the first short-circuit consumption time is equal to the pulse width of the second short-circuit consumption time.

[0015] In conjunction with the first aspect, in the fourth embodiment of the first aspect, the pulse width of the first short-circuit consumption time is greater than the pulse width of the second short-circuit consumption time.

[0016] In conjunction with the first aspect, in the fifth embodiment of the first aspect, the pulse width of the first short-circuit consumption time is smaller than the pulse width of the second short-circuit consumption time.

[0017] According to a second aspect, embodiments of the present invention provide a control signal for a brushed motor, including:

[0018] It consists of a first input signal, a second input signal, a first output signal, a second output signal, a third output signal, and a fourth output signal. The first input signal is electrically connected to the first and second output signals, and the second input signal is electrically connected to the third and fourth output signals.

[0019] The first input signal consists of several segments of cyclically set first high-level signals and second low-level signals, and the second input signal consists of several segments of cyclically set second low-level signals and second high-level signals. The sum of the pulse widths of the first high-level signals and the second low-level signals is equal to the sum of the pulse widths of the second low-level signals and the second high-level signals. The pulse width of the first low-level signal is greater than the pulse width of the second high-level signal. When the first low-level signal has been output for the first short-circuit consumption time, the second high-level signal starts to be output. When the output of the second high-level signal ends and the first low-level signal has been output for the second short-circuit consumption time, the first high-level signal starts to be output.

[0020] When the first input signal is set to the first high level signal, the first and second output signals are set to the high level and the low level respectively; when the first input signal is set to the first low level signal, the first and second output signals are set to the low level and the high level respectively.

[0021] When the second input signal is set to the second high level signal, the third and fourth output signals are set to the high level and the low level respectively. When the second input signal is set to the second low level signal, the third and fourth output signals are set to the low level and the high level respectively.

[0022] In conjunction with the second aspect, in the first embodiment of the second aspect, the pulse width of the first short-circuit consumption time is equal to the pulse width of the second short-circuit consumption time.

[0023] In conjunction with the second aspect, in the second embodiment of the second aspect, the pulse width of the first short-circuit consumption time is greater than the pulse width of the second short-circuit consumption time.

[0024] In conjunction with the second aspect, in the third embodiment of the second aspect, the pulse width of the first short-circuit consumption time is smaller than the pulse width of the second short-circuit consumption time.

[0025] The control circuit and control signal of the brushed motor of this utility model adjust the first input signal and the second input signal in the input signal to asymmetrical signals, and then release the electrical energy stored in the motor during the switching process by controlling the MOS transistor in the H-bridge circuit to turn on and off. By using the method of short-circuiting the MOS transistor, a large current is formed in the circuit, which converts the electrical energy into heat energy and consumes it. This eliminates the voltage spikes on the power bus formed during the switching process. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] in:

[0028] Figure 1 A circuit diagram of a brushed motor drive circuit in the prior art is shown;

[0029] Figure 2 It shows Figure 1 Timing diagram of the input signals IN1 and IN2 and the corresponding MOSFETs GS;

[0030] Figure 3 It shows Figure 1 A schematic diagram of the signal flow when operating in state 1;

[0031] Figure 4 It shows Figure 1 A schematic diagram of the signal flow when operating in state 2;

[0032] Figure 5 A circuit diagram of the control circuit for the brushed motor provided by this utility model is shown.

[0033] Figure 6 The timing diagrams of the first and second input signals of the brushed motor provided by this utility model and the corresponding MOSFETs GS are shown.

[0034] Figure 7 The diagram shows the signal flow in state 1 of the brushed motor circuit diagram provided by this utility model;

[0035] Figure 8 The diagram shows the signal flow in state 2 of the brushed motor circuit diagram provided by this utility model;

[0036] Figure 9 The diagram shows the signal flow in state 3 of the brushed motor circuit diagram provided by this utility model;

[0037] Figure 10 The diagram shows the signal flow in state 4 of the brushed motor circuit diagram provided by this utility model; Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0039] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0040] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" 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 application based on the specific circumstances.

[0041] Please see Figure 1 , Figure 1 This is a typical DC brushed motor drive circuit (i.e., a typical H-bridge circuit). The DC brushed motor drive circuit consists of four N-type MOSFETs forming an H-bridge circuit. A control circuit constitutes the entire DC brushed motor drive circuit. The H-bridge part of the circuit is powered by a single power supply (powered between V+ and GND). The control circuit has two input signals (IN1 and IN2), which are complementary and symmetrical. The two outputs of this DC brushed motor drive circuit are connected to the two ends of the DC motor respectively.

[0042] Conventional control methods can easily cause voltage spikes on the power bus during the rotation of a brushed DC motor, which can lead to overvoltage breakdown and damage to the MOSFETs in the H-bridge circuit in severe cases. Therefore, it is necessary to improve the control circuit of the brushed motor.

[0043] For details, please refer to Figure 2 , 3 and Figure 4 Assuming that in the initial state, IN1 and IN2 are input with a high-level signal and a low-level signal respectively, the entire driver circuit will have two operating modes: State 1 and State 2.

[0044] State 1 operating mode: When the IN1 terminal input is a high-level signal and the IN2 terminal input is a low-level signal, the control circuit outputs voltage. At this time, the HO1 and LO2 terminals output high-level signals, and MOSFETs M1 and M4 are turned on. The LO1 and HO2 terminals output low-level signals, and MOSFETs M2 and M3 are turned off. In the State 1 operating mode, the current signal flows from the V+ terminal → MOSFET M1 → motor M (load) → MOSFET M4 → GND terminal, and motor M rotates in the forward direction.

[0045] State 2 operating mode: When the input signal at the IN2 terminal is a high-level signal and the input signal at the IN1 terminal is a low-level signal, the control circuit outputs voltage. At this time, the LO1 and HO2 terminals output high-level signals, and MOSFETs M2 and M3 are turned on. The HO1 and LO2 terminals output low-level signals, and MOSFETs M1 and M4 are turned off. In the State 2 operating mode, the current signal flows from the V+ terminal → MOSFET M3 → motor M (load) → MOSFET M2 → GND terminal, and motor M rotates in the reverse direction.

[0046] Since the IN1 and IN2 terminals are connected to cyclic waveform signals and are completely symmetrical, the system will immediately return to the state 1 operating mode after the state 2 operating mode ends. However, in the state 1 operating mode, the windings of motor M store electrical energy, generating a back electromotive force. When switching from state 1 to state 2 and vice versa, the stored electrical energy in the windings of motor M is applied between the V+ and GND terminals. This causes voltage spikes on the power bus, severely affecting the reliability and stability of the H-bridge circuit. In fact, these voltage spikes may even damage the MOSFETs in the H-bridge circuit.

[0047] That is, due to the input signal, when the drive circuit switches from working mode 1 to working mode 2 and back to working mode 1, the electrical energy stored in the windings of motor M is applied between the V+ terminal and the GND terminal, causing a voltage spike on the power bus.

[0048] In summary, to ensure the overall reliability of the brushed motor drive circuit, it is necessary to provide a brushed motor control circuit with higher reliability and safety.

[0049] To address the aforementioned problems, this specification provides a control circuit for a brushed motor. For example... Figure 5 As shown, the circuit includes:

[0050] The system includes a control circuit, an H-bridge circuit, and a motor. The motor is electrically connected to the H-bridge circuit. The two outputs of the H-bridge circuit are electrically connected to the positive and negative terminals of the motor M, respectively. The H-bridge circuit is connected between the power supply terminal and ground, i.e., between V+ and GND. The H-bridge circuit still partially uses a single power supply. The control circuit has a first input terminal IN1, a second input terminal IN2, a first output terminal HO1, a second output terminal LO1, a third output terminal HO2, and a fourth output terminal LO2. The first input terminal IN1 is electrically connected to the first output terminal HO1 and the second output terminal LO1. The second input terminal IN2 is electrically connected to the third output terminal HO2 and the fourth output terminal LO2. The first output terminal HO1, the second output terminal LO1, the third output terminal HO2, and the fourth output terminal LO2 are electrically connected to the first MOSFET M1, the second MOSFET M2, the third MOSFET M3, and the fourth MOSFET M4 in the H-bridge circuit, respectively.

[0051] It can be seen that the circuit structure of this circuit is consistent with that of the driving circuit in the prior art, and no additional components are required. The overall circuit structure is simple and easy to debug.

[0052] It is understandable that the motor mentioned above is a brushed motor.

[0053] The first and second input signals in this circuit are asymmetrical, whereas existing technologies use completely symmetrical input waveforms. Therefore, the first output terminal HO1 (connected to the first input terminal IN1), the second output terminal LO1, and the third output terminal HO2 and the fourth output terminal LO2 (connected to the second input terminal IN2) also output four asymmetrical control voltages. These control voltages turn the corresponding MOSFETs on and off, releasing the electrical energy stored in the motor during switching. By short-circuiting the MOSFETs, a large current is generated in the circuit, converting the electrical energy into heat and dissipating it. This eliminates the voltage spikes on the power bus generated during switching.

[0054] Specifically, the first input terminal IN1 is used to receive the first input signal, and the second input terminal IN2 is used to receive the second input signal. The first input signal consists of several segments of a first high-level signal and a second low-level signal that are cyclically set. The second input signal consists of several segments of a second low-level signal and a second high-level signal that are cyclically set. The sum of the pulse widths of the first high-level signal and the second low-level signal is equal to the sum of the pulse widths of the second low-level signal and the second high-level signal. That is, the first period corresponding to the first input signal is equal to the second period corresponding to the second input signal (each period contains a high-level segment and a low-level segment).

[0055] When the first input terminal IN1 receives a first high-level signal, the first output terminal HO1 and the second output terminal LO1 are set to high and low levels, respectively. When the first input terminal IN1 receives a first low-level signal, the first output terminal HO1 and the second output terminal LO1 are set to low and high levels, respectively. When the second input terminal IN2 receives a second high-level signal, the third output terminal HO2 and the fourth output terminal LO2 are set to high and low levels, respectively. When the second input terminal IN2 receives a second low-level signal, the third output terminal HO2 and the fourth output terminal LO2 are set to low and high levels, respectively.

[0056] Unlike the control signals in the prior art, the pulse width of the first low-level signal is greater than the pulse width of the second high-level signal (i.e., the pulse width of the first high-level signal is less than the pulse width of the second low-level signal). The second high-level signal starts to be output when the first low-level signal has been output for the first short-circuit consumption time, and the first high-level signal starts to be output when the second high-level signal has finished outputting and the first low-level signal has been output for the second short-circuit consumption time.

[0057] It can be seen that the control signal composed of the first input signal and the second input signal is asymmetrical. The turn-on and turn-off sequence of the four MOS transistors in the H-bridge circuit can be controlled by the corresponding output signal to release electrical energy in the motor windings, thereby eliminating voltage spikes on the power supply bus.

[0058] For more details, please see Figures 6 to 10 Assuming that in the initial state, the first input terminal IN1 and the second input terminal IN2 are respectively input with a first high-level signal and a second low-level signal, the entire driving circuit will have four operating modes: state 1, state 2, state 3, and state 4.

[0059] State 1 operating mode: When the first input terminal IN1 receives a first high-level signal and the second input terminal IN2 receives a second low-level signal, the control circuit outputs voltage. At this time, the first output terminal HO1 and the fourth output terminal LO2 output high level, and MOSFETs M1 and M4 are turned on. The second output terminal LO1 and the third output terminal HO2 output low level, and MOSFETs M2 and M3 are turned off. In State 1 operating mode, the current signal flows from V+ terminal → MOSFET M1 → motor M (load) → MOSFET M4 → GND terminal, and motor M rotates in the forward direction.

[0060] State 2 Operating Mode: Since the first and second input signals are asymmetrical, the second input terminal IN2 remains at a low level. The control circuit output voltage maintains a low level at the first output terminal HO1 and the third output terminal HO2. MOSFETs M1 and M3 are turned off, while the second output terminal LO1 and the fourth output terminal LO2 are turned high. MOSFETs M2 and M4 are turned on. At this time, the electrical energy stored in the motor windings in the previous stage is released through the short circuit of MOSFETs M2 and M4. The first short circuit consumption time corresponding to the simultaneous on-time of MOSFETs M2 and M4 is the energy release time of the motor windings. Current signal flow direction in State 1 operating mode;

[0061] State 3 working mode: When the first input terminal IN1 receives a first low-level signal and the second input terminal IN2 receives a second high-level signal, the control circuit outputs voltage. The first output terminal HO1 and the fourth output terminal LO2 output low level, and MOSFETs M2 and M3 are turned on. The second output terminal LO1 and the third output terminal HO2 output high level, and MOSFETs M1 and M4 are turned off. In the state 1 working mode, the current signal flows from V+ terminal → MOSFET M3 → motor M (load) → M2 → GND terminal, and motor M rotates in reverse.

[0062] State 4 working mode: Similarly, since the first input signal and the second input signal are asymmetrical signals, the second input terminal IN2 signal is continuously at a low level. The output voltage of the control circuit is maintained at a low level at the first output terminal HO1 and the third output terminal HO2. MOSFETs M1 and M3 are turned off, the second output terminal LO1 and the fourth output terminal LO2 are at a high level, and MOSFETs M2 and M4 are turned on. At this time, the electrical energy stored in the motor winding in the previous stage is released through the short circuit of MOSFETs M2 and M4. The second short circuit consumption time corresponding to the time when M2 and M4 are turned on at the same time is the time when the electrical energy of the motor winding is released.

[0063] When the working mode of state 4 ends, it immediately returns to the working mode of state 1, and so on in a cycle.

[0064] Based on the above analysis of the working principle, the control circuit outputs a voltage signal to control the switching on and off of the four MOSFETs in the H-bridge circuit, thereby converting the electrical energy stored in the motor windings. The operating modes in states 2 and 4 consume the electrical energy of the motor windings. Therefore, in states 1 and 3, the motor windings will not generate voltage spikes to the power bus V+, improving the reliability of the entire circuit.

[0065] In this embodiment, the pulse width of the second low-level signal is equal to the pulse width of the second high-level signal. Alternatively, the pulse width of the second low-level signal can be set to be different from the pulse width of the second high-level signal, as long as the asymmetry between the first input signal and the second input signal is maintained.

[0066] Similarly, the pulse width of the first short-circuit consumption time can be equal to the pulse width of the second short-circuit consumption time, or the two times can be different. For example, the pulse width of the first short-circuit consumption time can be greater than the pulse width of the second short-circuit consumption time, or the pulse width of the first short-circuit consumption time can be less than the pulse width of the second short-circuit consumption time.

[0067] The first short-circuit consumption time and the second short-circuit consumption time correspond to the time when the motor releases the stored electrical energy in the operating modes of state 2 and state 4, respectively.

[0068] To address the aforementioned issues, this specification also provides a control signal for a brushed motor. This control signal comprises a first input signal, a second input signal, a first output signal, a second output signal, a third output signal, and a fourth output signal. The first input signal is electrically connected to the first and second output signals, and the second input signal is electrically connected to the third and fourth output signals. The first input signal consists of several cyclically configured segments of a first high-level signal and a second low-level signal, and the second input signal consists of several cyclically configured segments of a second low-level signal and a second high-level signal. The sum of the pulse widths of the first high-level signal and the second low-level signal is equal to the sum of the pulse widths of the second low-level signal and the second high-level signal, and the pulse width of the first low-level signal is greater than that of the second high-level signal. The pulse width is specified, and when the first low-level signal has been output for the first short-circuit consumption time, the second high-level signal starts to be output; when the second high-level signal output ends and the first low-level signal has been output for the second short-circuit consumption time, the first high-level signal starts to be output; when the first input signal is set to the first high-level signal, the first and second output signals are set to high and low levels respectively; when the first input signal is set to the first low-level signal, the first and second output signals are set to low and high levels respectively; when the second input signal is set to the second high-level signal, the third and fourth output signals are set to high and low levels respectively; when the second input signal is set to the second low-level signal, the third and fourth output signals are set to low and high levels respectively.

[0069] For details on how this control signal works, please refer to [reference needed]. Figures 5 to 10 The control circuit described above will not be repeated here.

[0070] The control circuit and control signal of the brushed motor of this utility model adjust the first input signal and the second input signal in the input signal to asymmetrical signals, and then release the electrical energy stored in the motor during the switching process by controlling the MOS transistor in the H-bridge circuit to turn on and off. By using the method of short-circuiting the MOS transistor, a large current is formed in the circuit, which converts the electrical energy into heat energy and consumes it. This eliminates the voltage spikes on the power bus formed during the switching process.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model 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. Such 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 this utility model.

Claims

1. A control circuit for a brushed motor, characterized in that, include: Control circuit, H-bridge circuit, and motor; The motor is electrically connected to the H-bridge circuit. The two outputs of the H-bridge circuit are electrically connected to the positive and negative terminals of the motor M, respectively. The H-bridge circuit is connected between the power supply terminal and ground. The control circuit has a first input terminal IN1, a second input terminal IN2, a first output terminal HO1, a second output terminal LO1, a third output terminal HO2, and a fourth output terminal LO2. The first input terminal IN1 is electrically connected to the first output terminal HO1 and the second output terminal LO1, and the second input terminal IN2 is electrically connected to the third output terminal HO2 and the fourth output terminal LO2. The first output terminal HO1, the second output terminal LO1, the third output terminal HO2, and the fourth output terminal LO2 are respectively electrically connected to the first MOSFET M1, the second MOSFET M2, the third MOSFET M3, and the fourth MOSFET M4 in the H-bridge circuit. The first input terminal IN1 is used to receive the first input signal, and the second input terminal IN2 is used to receive the second input signal. The first input signal consists of several segments of cyclically set first high-level signals and second low-level signals. The second input signal consists of several segments of cyclically set second low-level signals and second high-level signals. The sum of the pulse widths of the first high-level signals and the second low-level signals is equal to the sum of the pulse widths of the second low-level signals and the second high-level signals. The pulse width of the first low-level signal is greater than the pulse width of the second high-level signal. When the first low-level signal has been output for the first short-circuit consumption time, the second high-level signal starts to be output. When the second high-level signal output ends and the first low-level signal has been output for the second short-circuit consumption time, the first high-level signal starts to be output. When the first input terminal IN1 receives a first high-level signal, the first output terminal HO1 and the second output terminal LO1 are set to high level and low level respectively. When the first input terminal IN1 receives a first low-level signal, the first output terminal HO1 and the second output terminal LO1 are set to low level and high level respectively. When the second input terminal IN2 receives a second high-level signal, the third output terminal HO2 and the fourth output terminal LO2 are set to high level and low level, respectively. When the second input terminal IN2 receives a second low-level signal, the third output terminal HO2 and the fourth output terminal LO2 are set to low level and high level, respectively.

2. The control circuit for a brushed motor according to claim 1, characterized in that, The pulse width of the second low-level signal is equal to the pulse width of the second high-level signal.

3. The control circuit for a brushed motor according to claim 1, characterized in that, The pulse width of the second low-level signal is not equal to the pulse width of the second high-level signal.

4. The control circuit for a brushed motor according to claim 1, characterized in that, The pulse width of the first short circuit duration is equal to the pulse width of the second short circuit duration.

5. The control circuit for a brushed motor according to claim 1, characterized in that, The pulse width of the first short-circuit consumption time is greater than the pulse width of the second short-circuit consumption time.

6. The control circuit for a brushed motor according to claim 1, characterized in that, The pulse width of the first short-circuit consumption time is less than the pulse width of the second short-circuit consumption time.

7. A control signal for a brushed motor, characterized in that, include: It consists of a first input signal, a second input signal, a first output signal, a second output signal, a third output signal, and a fourth output signal. The first input signal is electrically connected to the first and second output signals, and the second input signal is electrically connected to the third and fourth output signals. The first input signal consists of several segments of cyclically set first high-level signals and second low-level signals, and the second input signal consists of several segments of cyclically set second low-level signals and second high-level signals. The sum of the pulse widths of the first high-level signals and the second low-level signals is equal to the sum of the pulse widths of the second low-level signals and the second high-level signals. The pulse width of the first low-level signal is greater than the pulse width of the second high-level signal. When the first low-level signal has been output for the first short-circuit consumption time, the second high-level signal starts to be output. When the output of the second high-level signal ends and the first low-level signal has been output for the second short-circuit consumption time, the first high-level signal starts to be output. When the first input signal is set to the first high level signal, the first and second output signals are set to the high level and the low level respectively; when the first input signal is set to the first low level signal, the first and second output signals are set to the low level and the high level respectively. When the second input signal is set to the second high level signal, the third and fourth output signals are set to the high level and the low level respectively. When the second input signal is set to the second low level signal, the third and fourth output signals are set to the low level and the high level respectively.

8. The control signal for the brushed motor according to claim 7, characterized in that, The pulse width of the first short circuit duration is equal to the pulse width of the second short circuit duration.

9. The control signal for a brushed motor according to claim 7, characterized in that, The pulse width of the first short-circuit consumption time is greater than the pulse width of the second short-circuit consumption time.

10. The control signal for a brushed motor according to claim 7, characterized in that, The pulse width of the first short-circuit consumption time is less than the pulse width of the second short-circuit consumption time.

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