Motor control circuit and motor control system

Abstract

The utility model discloses a motor control circuit and a motor control system, the motor control circuit comprises a driving unit, a switch unit, a sampling unit and a control unit, the driving unit is used for generating a driving voltage based on a driving signal; the switch unit is used for controlling the first output node to receive the driving voltage and form a motor working loop, and controlling the second output node to receive the driving voltage and form a motor braking loop; the sampling unit is used for generating a first sampling signal based on the working current of the driving unit, and generating a second sampling signal based on the voltage on the first output node and / or the voltage on the second output node; the control unit is connected with the sampling unit and used for adjusting the driving signal based on the first sampling signal and the second sampling signal. The circuit is simple in structure, a power resistor is not needed, kinetic energy of the motor is converted into heat energy through the multiplexing driving unit, the braking speed is adjusted in a multi-stage mode through the control unit, and the braking time is greatly shortened.

Description

Technical Field

[0001] This utility model belongs to the field of integrated circuit technology, specifically relating to a motor control circuit and a motor control system. Background Technology

[0002] Centrifuges are primarily used in biochemistry laboratories and various research institutions for medical testing and research, enabling the stratification and separation of mixed liquids. During operation, the centrifuge's built-in motor runs at very high speeds, and the centrifugal rotor possesses substantial kinetic energy. When the motor stops, it needs to be braked. Motor braking methods include dynamic braking and static braking. Existing dynamic braking methods require energy feedback devices and have complex circuit designs, resulting in high braking costs. Existing static braking methods have longer braking times.

[0003] Therefore, in order to address the above-mentioned technical problems, it is necessary to provide a motor control circuit and a motor control system. Utility Model Content

[0004] The purpose of this utility model is to provide a motor control circuit and a motor control system that can achieve multi-level speed regulation and braking with low circuit cost, and can reduce braking time through kinetic energy and thermal energy conversion.

[0005] To achieve the above objectives, the technical solution provided by a specific embodiment of this utility model is as follows:

[0006] A motor control circuit includes: a drive unit, a switching unit, a sampling unit, and a control unit;

[0007] The driving unit is used to generate a driving voltage based on a driving signal;

[0008] The switching unit is connected between the power supply voltage and the reference voltage, and is connected to the first output node, the second output node and the first end of the drive unit. The switching unit is used to control the first output node to receive the drive voltage and form a motor working circuit, and to control the second output node to receive the drive voltage and form a motor braking circuit.

[0009] The sampling unit is connected to the second terminal, the first output node and the second output node of the driving unit. The sampling unit is used to generate a first sampling signal based on the operating current of the driving unit, and to generate a second sampling signal based on the voltage on the first output node and / or the voltage on the second output node.

[0010] The control unit is connected to the sampling unit and is used to adjust the drive signal based on the first sampling signal and the second sampling signal.

[0011] In one or more embodiments of the present invention, the driving unit includes a transistor, a first terminal of the transistor is connected to the sampling unit and forms a second terminal of the driving unit, the second terminal of the transistor is connected to the switching unit and forms a first terminal of the driving unit, and the control terminal of the transistor receives the driving signal.

[0012] In one or more embodiments of this utility model, the driving unit further includes a voltage regulator module, which includes a first resistor, a second resistor, a first diode, and a second diode; a first end of the first resistor is connected to the cathode of the first diode to receive the driving signal, a second end of the first resistor is connected to the control terminal of the transistor, the anode of the first diode is connected to the first end of the second resistor, a second end of the second resistor is connected to the control terminal of the transistor, the cathode of the second diode is connected to the control terminal of the transistor, and the anode of the second diode is connected to a reference voltage.

[0013] In one or more embodiments of the present invention, in a first state, the switching unit is used to control the first output node to be connected to the first end of the driving unit, and the second output node is connected to the power supply voltage, wherein the power supply voltage, the second output node, the first output node and the driving unit form a motor working circuit;

[0014] In the second state, the switching unit is used to control the first output node to be connected to the reference voltage, and the second output node to be connected to the first end of the drive unit. The reference voltage, the first output node, the second output node and the drive unit form a motor braking circuit.

[0015] In one or more embodiments of this utility model, the switching unit includes a first switch and a second switch; the first contact of the first switch is connected to the first output node, the second contact of the first switch is connected to a reference voltage, and the third contact of the first switch is connected to the first end of the driving unit; the first contact of the second switch is connected to the second output node, the second contact of the second switch is connected to the first end of the driving unit, and the third contact of the second switch is connected to a power supply voltage.

[0016] In one or more embodiments of the present invention, the sampling unit includes a first sampling unit and a voltage sampling unit; the first sampling unit is connected between the second terminal of the driving unit and the reference voltage, and the output terminal of the first sampling unit is connected to the control unit; the first sampling unit is used to generate the first sampling signal at the output terminal of the first sampling unit based on the operating current of the driving unit.

[0017] The second sampling unit is connected to the first output node and the second output node, and the output terminal of the second sampling unit is connected to the control unit. The second sampling unit is used to generate the second sampling signal at the output terminal of the second sampling unit based on the voltage on the first output node and / or the voltage on the second output node.

[0018] In one or more embodiments of the present invention, the first sampling unit includes at least one first sampling resistor, a second sampling resistor, and a first capacitor; the first end of the first sampling resistor is connected to the second end of the driving unit, and the second end of the first sampling resistor is connected to a reference voltage; the first end of the second sampling resistor is connected to the second end of the first sampling resistor, and the second end of the second sampling resistor is connected to the first end of the first capacitor to form the output terminal of the first sampling unit, and the second end of the first capacitor is connected to the reference voltage.

[0019] In one or more embodiments of this utility model, the second sampling unit includes a third sampling resistor unit, a fourth sampling resistor, and a second capacitor. The third sampling resistor unit includes one or more third sampling resistors connected in series. The first end of the third sampling resistor unit is connected to the first output node and the second output node. The second end of the third sampling resistor unit is connected to the first end of the fourth sampling resistor and the first end of the second capacitor to form the output terminal of the second sampling unit. The second end of the fourth sampling resistor and the second end of the second capacitor are connected to a reference voltage.

[0020] In one or more embodiments of the present invention, the motor control circuit further includes a voltage regulator, the first end of which is connected to the second output node and the first output node.

[0021] In one or more embodiments of this utility model, the driving signal includes a PWM signal, and the control unit includes a comparison module and an adjustment module; the comparison module is connected to the sampling unit, and the comparison module is used to compare a second sampling signal and a threshold signal to generate a comparison result signal; the adjustment module is connected to the comparison module, and is used to generate the PWM signal, and set the initial frequency and initial duty cycle of the PWM signal based on the second sampling signal, and adjust the frequency and duty cycle of the driving signal step by step based on the comparison result signal, the first sampling signal and the second sampling signal.

[0022] The technical solution provided by a specific embodiment of this utility model is as follows: a motor control system includes: a motor control circuit and a motor coil; the motor control circuit is the motor control circuit described in any embodiment; the first end of the motor coil is connected to the first output node, and the second end of the motor coil is connected to the second output node.

[0023] In one or more embodiments of the present invention, the motor control system further includes a heat dissipation device, the two ends of which are respectively connected to a reference voltage, and the heat dissipation device is disposed above or beside the drive unit.

[0024] In one or more embodiments of the present invention, the motor control system further includes a thermally conductive pad disposed between the drive unit and the heat dissipation device.

[0025] Compared with the prior art, the motor control circuit and motor control system of this utility model have a simple circuit structure. The motor working circuit and the motor braking circuit are switched by a switching unit, and the drive unit is reused in the motor working circuit and the motor braking circuit. By converting the motor kinetic energy during the braking process into heat energy on the drive unit, and by adjusting the braking speed in multiple stages through the control unit, the braking time is greatly reduced. 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 recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a system block diagram of the motor control circuit in this utility model;

[0028] Figure 2 This is a circuit diagram of the motor control circuit in Embodiment 1 of this utility model;

[0029] Figure 3 This is a circuit diagram of the motor control system in Embodiment 2 of this utility model.

[0030] Key reference numerals:

[0031] 10-Drive unit, 11-Voltage regulator module, 20-Switching unit, 21-First switch, 22-Second switch

[0032] 30 - Sampling unit, 31 - First sampling unit, 32 - Second sampling unit, 40 - Control unit

[0033] 41-Comparison module, 42-Adjustment module, 50-Power supply voltage, 60-Heat dissipation device, 70-Motor coil,

[0034] 71 - Resonant unit. Detailed Implementation

[0035] To enable those skilled in the art to better understand the technical solutions of this utility model, 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, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0036] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0037] The terms "coupled," "connected," or "linked" in this specification include both direct and indirect connections. An indirect connection is a connection made through an intermediate medium, such as an electrical conduction medium, which may have parasitic inductance or capacitance. Indirect connections may also include connections made through other active or passive devices to achieve the same or similar functional purpose, such as connections through switches, follower circuits, or other circuits or components. Furthermore, in this invention, terms such as "first" and "second" are primarily used to distinguish one technical feature from another, and do not necessarily require or imply any actual relationship, quantity, or order between these technical features.

[0038] In the detailed description of this specification, reference is made to the accompanying drawings, which form a part thereof, wherein like reference numerals always denote like parts, and wherein exemplary embodiments are shown by way of example that may be implemented. It should be understood that other embodiments may be utilized, and structural or logical changes may be made, without departing from the scope of this application. Therefore, the following detailed description should not be considered limiting.

[0039] The various operations in the specification may be described sequentially as multiple discrete actions or operations in a manner most conducive to understanding the claimed subject matter. However, the order of description should not be construed as implying that these operations must be sequentially related. Specifically, these operations may not be performed in the order presented. The described operations may be performed in a different order than in the described embodiments. Various additional operations may be performed in additional embodiments and / or the described operations may be omitted.

[0040] For the purposes of this application, the phrase "A and / or B" means (A), (B), or (A and B). For the purposes of this application, the phrase "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0041] Various components and devices may be referred to or shown in the singular (e.g., “MOS transistor”, “transistor”, “switch”, etc.) in this document, but only for the convenience of discussion, and any element referred to in the singular may include multiple such elements as taught herein.

[0042] The description uses the phrases "in this embodiment," "in other embodiments," or "in some embodiments," each of which may refer to one or more of the same or different embodiments. Furthermore, the terms "comprising," "including," "having," etc., used in relation to embodiments of this application are synonymous.

[0043] like Figure 1 As shown, a motor control circuit of this utility model includes: a drive unit 10, a switch unit 20, a sampling unit 30, and a control unit 40.

[0044] The drive unit 10 is used to generate a drive voltage V1 based on the drive signal Control;

[0045] The switching unit 20 is connected between the power supply voltage 50 and the reference voltage DGND, and is connected to the first output node P1, the second output node P2 and the first end of the drive unit 10. The switching unit 20 is used to control the first output node P1 to receive the drive voltage V1 and form a motor working circuit, and to control the second output node P2 to receive the drive voltage V1 and form a motor braking circuit.

[0046] The sampling unit 30 is connected to the second terminal of the driving unit 10, the first output node P1 and the second output node P2. The sampling unit 30 is used to generate a first sampling signal S1 based on the operating current of the driving unit 10, and to generate a second sampling signal S2 based on the voltage on the first output node P1 and / or the voltage on the second output node P2.

[0047] The control unit 40 is connected to the sampling unit 30 and is used to adjust the drive signal Control based on the first sampling signal S1 and the second sampling signal S2.

[0048] This utility model also discloses a motor control system, including the above-mentioned motor control circuit and motor coil, wherein the first end of the motor coil is connected to the first output node P1, and the second end of the motor coil is connected to the second output node P2.

[0049] This invention achieves static braking without the need for a power resistor, converting the rotor kinetic energy of the motor into heat energy on the drive unit 10, and using the control unit 40 to adjust the braking speed in multiple stages, thus greatly reducing braking time.

[0050] The present invention will be further described below with reference to specific embodiments.

[0051] Example 1:

[0052] like Figure 2 As shown, a motor control circuit in this embodiment includes: a drive unit 10, a switch unit 20, a sampling unit 30, and a control unit 40.

[0053] The drive unit 10 is used to generate a drive voltage V1 based on the drive signal Control.

[0054] Switching unit 20 is connected between power supply voltage 50 and reference voltage DGND, and is connected to the first output node P1, the second output node P2, and the first terminal of drive unit 10. Switching unit 20 is used to control the first output node P1 to receive drive voltage V1 and form a motor working circuit, and to control the second output node P2 to receive drive voltage V1 and form a motor braking circuit. For example, the reference voltage DGND is ground voltage DGND.

[0055] The sampling unit 30 is connected to the second terminal of the driving unit 10, the first output node P1 and the second output node P2. The sampling unit 30 is used to generate a first sampling signal S1 based on the operating current of the driving unit 10, and to generate a second sampling signal S2 based on the voltage on the first output node P1 and / or the voltage on the second output node P2.

[0056] The control unit 40 is connected to the sampling unit 30 and is used to adjust the drive signal Control based on the first sampling signal S1 and the second sampling signal S2.

[0057] Specifically, the driving unit 10 includes a transistor Q1 and a voltage regulator module 11. The first terminal of transistor Q1 is connected to the sampling unit 30 and forms the second terminal of the driving unit 10. The second terminal of transistor Q1 is connected to the switching unit 20 and forms the first terminal of the driving unit 10. The control terminal of transistor Q1 receives the driving signal Control.

[0058] For example, transistor Q1 is an N-channel insulated-gate bipolar transistor (IGBT) or an N-channel MOSFET. The first terminal of transistor Q1 is the emitter, the second terminal is the collector, and the control terminal is the base. Further, the rated voltage (i.e., the maximum collector-emitter voltage) of transistor Q1 is greater than or equal to 650V, and the continuous current (i.e., the maximum collector current that transistor Q1 can continuously pass under normal operating conditions) is greater than or equal to 30A.

[0059] For example, the voltage regulator module 11 includes a first resistor R1, a second resistor R2, a first diode D1, and a second diode D2. The first terminal of the first resistor R1 is connected to the cathode of the first diode D1 to receive a drive signal Control. The second terminal of the first resistor R1 is connected to the control terminal of the transistor Q1. The anode of the first diode D1 is connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is connected to the control terminal of the transistor Q1. The cathode of the second diode D2 is connected to the control terminal of the transistor Q1. The anode of the second diode D2 is connected to the reference voltage DGND.

[0060] In the first state, the switching unit 20 is used to control the first output node P1 to be connected to the first end of the drive unit 10, and the second output node P2 to be connected to the power supply voltage 50. The power supply voltage 50, the second output node P2, the first output node P1 and the drive unit 10 form a motor working circuit.

[0061] In the second state, the switching unit 20 is used to control the first output node P1 to be connected to the reference voltage DGND, and the second output node P2 to be connected to the first terminal of the drive unit 10. The reference voltage DGND, the first output node P1, the second output node P2 and the drive unit 10 form a motor braking circuit.

[0062] Furthermore, the switching unit 20 includes a first switch 21 and a second switch 22. The first contact 6 of the first switch 21 is connected to the first output node P1, the second contact 7 of the first switch 21 is connected to the reference voltage DGND, and the third contact 5 of the first switch 21 is connected to the first terminal of the driving unit 10. The first contact 3 of the second switch 22 is connected to the second output node P2, the second contact 2 of the second switch 22 is connected to the first terminal of the driving unit 10, and the third contact 4 of the second switch 22 is connected to the power supply voltage 50.

[0063] like Figure 2 As shown, the sampling unit 30 includes a first sampling unit 31 and a voltage sampling unit 32.

[0064] The first sampling unit 31 is connected between the second terminal of the driving unit 10 and the reference voltage, and the output terminal of the first sampling unit 31 is connected to the control unit 40. The first sampling unit 31 is used to generate a first sampling signal S1 at the output terminal of the first sampling unit 31 based on the operating current of the driving unit 10 (i.e., the operating current of transistor Q1). It should be noted that the reference voltage in this embodiment includes the digital ground potential DGND and the power ground potential PGND, thereby avoiding signal crosstalk and improving circuit reliability.

[0065] The second sampling unit 32 is connected to the first output node P1 and the second output node P2, and the output terminal of the second sampling unit 32 is connected to the control unit 40. The second sampling unit 32 is used to generate a second sampling signal S2 based on the voltage on the first output node P1 or the voltage on the second output node P2 at the output terminal of the second sampling unit 3230.

[0066] In this embodiment, the first sampling unit 31 includes at least one first sampling resistor R11, a second sampling resistor R12, and a first capacitor C1. The first terminal of the first sampling resistor R11 is connected to the second terminal of the driving unit 10, and the second terminal of the first sampling resistor R11 is connected to the reference voltage PGND. The first terminal of the second sampling resistor R12 is connected to the second terminal of the first sampling resistor R11, and the second terminal of the second sampling resistor R12 is connected to the first terminal of the first capacitor C1 to form the output terminal of the first sampling unit 31. The second terminal of the first capacitor C1 is connected to the reference voltage DGND.

[0067] For example, the first sampling unit 31 includes four first sampling resistors R11 connected in parallel. Further, in this embodiment, the first sampling unit 31 also includes a third resistor R3, the first end of which is connected to the first end of the first capacitor C1, and the second end of which is connected to the reference voltage DGND.

[0068] In this embodiment, the second sampling unit 32 includes a third sampling resistor unit, a fourth sampling resistor R14, and a second capacitor C2. The third sampling resistor unit includes one or more third sampling resistors R13 connected in series. The first terminal of the third sampling resistor unit is connected to the first output node P1 and the second output node P2. The second terminal of the third sampling resistor unit is connected to the first terminal of the fourth sampling resistor R14 and the first terminal of the second capacitor C2 to form the output terminal of the second sampling unit 32. The second terminal of the fourth sampling resistor R14 and the second terminal of the second capacitor C2 are connected to the reference voltage DGND. Exemplarily, the third sampling resistor R13 unit includes four third sampling resistors R13 connected in series.

[0069] Furthermore, the motor control circuit also includes a voltage regulator, with one terminal connected to the second output node P2 and the other terminal connected to the first output node P1. For example, the voltage regulator includes a Zener diode Z1, with the anode of Z1 connected to the first output node P1 and the cathode of Z1 connected to the second output node P2.

[0070] In this embodiment, the drive signal Control includes a PWM signal, and the control unit 40 includes a comparison module 41 and an adjustment module 42.

[0071] The comparison module 41 is connected to the sampling unit 30. The comparison module 41 is used to compare the second sampling signal S2 and the threshold signal to generate a comparison result signal.

[0072] The adjustment module 42 is connected to the comparison module 41 and is used to generate a PWM signal. It sets the initial frequency and initial duty cycle of the PWM signal based on the second sampling signal S2, and adjusts the frequency and duty cycle of the drive signal Control step by step based on the comparison result signal, the first sampling signal S1 and the second sampling signal S2.

[0073] In the first state, the first contact 6 and the third contact 5 of the first switch 21 are engaged to connect the first output node P1 to the first end of the drive unit 10. The first contact 3 and the third contact 4 of the second switch 22 are engaged to connect the second output node P2 to the power supply voltage 50. The power supply voltage 50, the second output node P2, the first output node P1, and the drive unit 10 form a motor operating circuit. For example, the power supply voltage 50 is a 48V power supply, and both the first output node P1 and the second output node P2 are connected to the motor coil 70. The drive signal Control controls the switching on and off of the transistor Q1 in the drive unit 10, thereby adjusting the motor speed.

[0074] In the second state (i.e., when rapid braking of the motor is required), the first contact 3 and the second contact 7 of the first switch 21 are engaged to connect the first output node P1 to the reference voltage DGND. The first contact 3 and the second contact 2 of the second switch 22 are engaged to connect the second output node P2 to the first terminal of the drive unit 10. The reference voltage DGND, the first output node P1, the second output node P2, and the drive unit 10 form a motor braking circuit. At this time, the motor braking speed is still controlled by turning the transistor Q1 in the drive unit 10 on and off via the drive signal Control.

[0075] It should be noted that, compared to existing static braking methods, this embodiment does not require a power resistor. Instead, it uses a drive signal Control to control the short-circuit time of transistor Q1, converting the rotor's kinetic energy into heat energy on transistor Q1. The motor braking strategy in this embodiment balances braking speed control with the temperature rise of transistor Q1, satisfying the need for rapid braking while ensuring that transistor Q1 is not damaged due to overheating.

[0076] This embodiment can set a multi-level braking strategy through the control unit 40, adjusting the braking speed step by step, thus greatly reducing the braking time. For example, when braking begins, the current user braking level is first read, and the initial frequency f and initial duty cycle D of the drive signal Control are set based on the second sampling signal S2. Then, based on the first sampling signal S1 (i.e., the magnitude I of the current discharge current of transistor Q1), the total discharge energy I is calculated. 2 Based on the second sampled signal S2 and the total discharge energy, the frequency f and duty cycle D of the drive signal Control are adjusted in steps again until the second sampled signal S2 is less than the threshold signal.

[0077] Example 2:

[0078] like Figure 3 As shown, a motor control system includes a motor control circuit and a motor coil 70. The motor control circuit includes a drive unit 10, a switching unit 20, a sampling unit 30, and a control unit 40. The drive unit 10 generates a drive voltage V1 based on a drive signal Control. The switching unit 20 is connected between a power supply voltage 50 and a reference voltage DGND, and is connected to a first output node P1, a second output node P2, and a first terminal of the drive unit 10. The switching unit 20 controls the first output node P1 to receive the drive voltage V1 and form a motor operating circuit, and controls the second output node P2 to receive the drive voltage V1 and form a motor braking circuit. The sampling unit 30 is connected to a second terminal of the drive unit 10, the first output node P1, and the second output node P2. The sampling unit 30 generates a first sampling signal S1 based on the operating current of the drive unit 10, and generates a second sampling signal S2 based on the voltage on the first output node P1 and / or the voltage on the second output node P2. The control unit 40 is connected to the sampling unit 30 and adjusts the drive signal Control based on the first sampling signal S1 and the second sampling signal S2.

[0079] The circuit structure and working principle of the motor control circuit in this embodiment are the same as those described in Embodiment 1, and will not be repeated here. The first end of the motor coil 70 is connected to the first output node P1, and the second end of the motor coil 70 is connected to the second output node P2.

[0080] The motor control system in this embodiment also includes a heat sink 60. The two ends of the heat sink 60 are connected to the reference voltage DGND, and the heat sink 60 is disposed above or beside the drive unit 10. For example, the heat dissipation area of ​​the heat sink is greater than or equal to 17065 mm². 2 The thermal resistance of the heat dissipation device is less than or equal to 3.5℃ / W.

[0081] The motor control system in this embodiment also includes a thermally conductive pad, which is disposed between the drive unit 10 and the heat dissipation device. The thermally conductive pad is a dielectric phase change thermally conductive material, used to insulate the transistor Q1 and the heat dissipation device, and to ensure the thermal conductivity between the transistor Q1 and the heat dissipation device.

[0082] like Figure 3 As shown, the motor control system in this embodiment also includes a resonant unit 71. The resonant unit 71 includes a third capacitor C3 and a fourth resistor R4. The first end of the third capacitor C3 is connected to the second end of the motor coil 70, the second end of the third capacitor C3 is connected to the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is connected to the first end of the motor coil 70.

[0083] As can be seen from the above technical solutions, this utility model has the following beneficial effects:

[0084] Compared with existing static braking methods, the circuit structure of this invention is simple, does not require the setting of power resistors, reuses the drive unit 10 during motor operation and braking, and switches the motor operation circuit and motor braking circuit through the switch unit 20, thus saving circuit costs.

[0085] The kinetic energy of the motor rotor is converted into heat energy on the drive unit 10, and the braking speed is adjusted in multiple stages through the control unit 40, which greatly reduces the braking time.

[0086] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0087] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A motor control circuit, characterized in that, include: Drive unit, switching unit, sampling unit, and control unit; The driving unit is used to generate a driving voltage based on a driving signal; The switching unit is connected between the power supply voltage and the reference voltage, and is connected to the first output node, the second output node and the first end of the drive unit. The switching unit is used to control the first output node to receive the drive voltage and form a motor working circuit, and to control the second output node to receive the drive voltage and form a motor braking circuit. The sampling unit is connected to the second terminal, the first output node and the second output node of the driving unit. The sampling unit is used to generate a first sampling signal based on the operating current of the driving unit, and to generate a second sampling signal based on the voltage on the first output node and / or the voltage on the second output node. The control unit is connected to the sampling unit and is used to adjust the drive signal based on the first sampling signal and the second sampling signal.

2. The motor control circuit according to claim 1, characterized in that, The driving unit includes a transistor. The first terminal of the transistor is connected to the sampling unit and forms the second terminal of the driving unit. The second terminal of the transistor is connected to the switching unit and forms the first terminal of the driving unit. The control terminal of the transistor receives the driving signal.

3. The motor control circuit according to claim 2, characterized in that, The driving unit further includes a voltage regulator module, which includes a first resistor, a second resistor, a first diode, and a second diode. The first end of the first resistor is connected to the cathode of the first diode to receive the drive signal, the second end of the first resistor is connected to the control terminal of the transistor, the anode of the first diode is connected to the first end of the second resistor, the second end of the second resistor is connected to the control terminal of the transistor, the cathode of the second diode is connected to the control terminal of the transistor, and the anode of the second diode is connected to a reference voltage.

4. The motor control circuit according to claim 1, characterized in that, In the first state, the switching unit is used to control the first output node to be connected to the first end of the driving unit, and the second output node is connected to the power supply voltage. The power supply voltage, the second output node, the first output node and the driving unit form a motor working circuit. In the second state, the switching unit is used to control the first output node to be connected to the reference voltage, and the second output node to be connected to the first end of the drive unit. The reference voltage, the first output node, the second output node and the drive unit form a motor braking circuit.

5. The motor control circuit according to claim 1, characterized in that, The switching unit includes a first switch and a second switch; The first contact of the first switch is connected to the first output node, the second contact of the first switch is connected to the reference voltage, and the third contact of the first switch is connected to the first end of the drive unit. The first contact of the second switch is connected to the second output node, the second contact of the second switch is connected to the first end of the drive unit, and the third contact of the second switch is connected to the power supply voltage.

6. The motor control circuit according to claim 1, characterized in that, The sampling unit includes a first sampling unit and a second sampling unit; The first sampling unit is connected between the second terminal of the driving unit and the reference voltage, and the output terminal of the first sampling unit is connected to the control unit. The first sampling unit is used to generate the first sampling signal at the output terminal of the first sampling unit based on the operating current of the driving unit. The second sampling unit is connected to the first output node and the second output node, and the output terminal of the second sampling unit is connected to the control unit. The second sampling unit is used to generate the second sampling signal at the output terminal of the second sampling unit based on the voltage on the first output node and / or the voltage on the second output node.

7. The motor control circuit according to claim 6, characterized in that, The first sampling unit includes at least one first sampling resistor, a second sampling resistor, and a first capacitor; The first end of the first sampling resistor is connected to the second end of the driving unit, and the second end of the first sampling resistor is connected to the reference voltage. The first end of the second sampling resistor is connected to the second end of the first sampling resistor, the second end of the second sampling resistor is connected to the first end of the first capacitor to form the output terminal of the first sampling unit, and the second end of the first capacitor is connected to the reference voltage.

8. The motor control circuit according to claim 6, characterized in that, The second sampling unit includes a third sampling resistor unit, a fourth sampling resistor, and a second capacitor. The third sampling resistor unit includes one or more third sampling resistors connected in series. The first end of the third sampling resistor unit is connected to the first output node and the second output node. The second end of the third sampling resistor unit is connected to the first end of the fourth sampling resistor and the first end of the second capacitor to form the output terminal of the second sampling unit. The second end of the fourth sampling resistor and the second end of the second capacitor are connected to the reference voltage.

9. The motor control circuit according to claim 1, characterized in that, The motor control circuit also includes a voltage regulator, the first end of which is connected to the second output node and the first output node.

10. The motor control circuit according to claim 1, characterized in that, The drive signal includes a PWM signal, and the control unit includes a comparison module and an adjustment module; The comparison module is connected to the sampling unit, and the comparison module is used to compare the second sampling signal and the threshold signal to generate a comparison result signal. The adjustment module is connected to the comparison module and is used to generate the PWM signal, and set the initial frequency and initial duty cycle of the PWM signal based on the second sampling signal, and adjust the frequency and duty cycle of the drive signal step by step based on the comparison result signal, the first sampling signal and the second sampling signal.

11. A motor control system, characterized in that, include: Motor control circuit and motor coil; The motor control circuit is the motor control circuit according to any one of claims 1 to 10; The first end of the motor coil is connected to the first output node, and the second end of the motor coil is connected to the second output node.

12. The motor control system according to claim 11, characterized in that, The motor control system also includes a heat dissipation device, the two ends of which are connected to a reference voltage, and the heat dissipation device is disposed above or beside the drive unit.

13. The motor control system according to claim 12, characterized in that, The motor control system also includes a thermally conductive pad, which is disposed between the drive unit and the heat dissipation device.

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