A motor drive circuit and a switch tube drive circuit thereof

Abstract

The present invention provides a motor drive circuit and a switch tube drive circuit thereof, wherein the switch tube drive circuit comprises a comparator and a state detection module, wherein the inverting input terminal of each comparator is connected to the state detection module, the non-inverting input terminal is connected to the control signal output interface on the controller, and the output terminal is connected to the control electrode of the switch tube in the H-bridge motor drive circuit; the state detection module is used to detect whether the controller is in a power-on and / or reset state; when the controller is in a power-on and / or reset state, the state detection module sends a high potential signal to the inverting input terminal of the comparator, otherwise it sends a low potential signal to the inverting input terminal of the comparator. According to the technical solution provided by the present invention, when the controller is powered on or reset, the driven switch tube cannot receive the control signal sent by the controller, and the phenomenon of simultaneous conduction of the same-side switch tubes will not occur in the H-bridge drive circuit, so the safety of the H-bridge drive circuit can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and in particular relates to a motor drive circuit and a switch tube drive circuit thereof. Background Art

[0002] The H-bridge drive circuit is a very typical motor drive circuit. Its structure is as follows: Figure 1 As shown, there are four switch tubes, T1, T2, T3 and T4, and the motor is driven by controlling the on and off of each switch tube. Since the shape of the motor drive circuit resembles the letter H, it is called an H-bridge drive circuit.

[0003] When the H-bridge driving circuit is working, one of the switching tubes is turned on to the positive pole to pull up the motor potential, and the other MOS tube is turned on to the negative pole to pull down the motor potential. The motor is driven by switching.

[0004] Each switch tube in the H-bridge drive circuit is usually driven and controlled by a drive signal generated by a controller such as a single-chip microcomputer. However, when the controller is powered on or reset, its pins are generally in an input state. If it is interfered by the outside world at this time, the switch tubes on the same side of the H-bridge drive circuit will be turned on, and the motor will work abnormally. If the switch tubes on the same side of the H-bridge drive circuit are turned on, a short circuit will occur between the positive and negative poles of the power supply, burning out the switch tubes set on the bridge arm, resulting in poor safety of the H-bridge drive circuit. Summary of the invention

[0005] The object of the present invention is to provide a motor drive circuit and a switch tube drive circuit thereof, which are used to solve the problem that in the existing switch tube control circuit, when the controller is powered on or reset, the controller pin is in the input state, causing the switch tube on the same side of the H-bridge drive circuit to be turned on, thereby causing the H-bridge drive circuit to have poor safety.

[0006] To achieve the above purpose, the technical solution provided by the present invention is:

[0007] A motor drive circuit comprises a controller and an H-bridge motor drive circuit composed of a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the control electrode of each switch tube is respectively provided with a corresponding switch tube drive circuit;

[0008] Among the switch tubes on the same side of the H-bridge motor drive circuit, the drive circuit of at least one switch tube is an anti-malfunction switch tube drive circuit;

[0009] Each anti-malfunction switch tube driving circuit includes a corresponding comparator and a state detection module, the inverting input end of each comparator is connected to the corresponding state detection module, the non-phase input end is connected to the corresponding control signal output interface on the controller, and the output end is connected to the control electrode of the corresponding switch tube in the H-bridge motor driving circuit;

[0010] The state detection module is used to detect whether the controller is in a power-on and / or reset state; when the controller is in a power-on and / or reset state, the state detection module sends a high potential signal to the inverting input terminal of the corresponding comparator, otherwise it sends a low potential signal to the inverting input terminal of the corresponding comparator.

[0011] The technical solution provided by the present invention is provided with a comparator in the anti-maloperation switch tube driving circuit. Under the action of the comparator, when the controller is powered on or reset, the driven switch tube cannot receive the control signal sent by the controller, and the phenomenon of the switch tubes on the same side being turned on at the same time will not occur in the H-bridge driving circuit, so the safety of the H-bridge driving circuit can be improved.

[0012] As a further improvement to the status detection module, each status detection module includes a corresponding fifth switch tube; the anode of each fifth switch tube is connected to the inverting input terminal of the corresponding comparator, the cathode and the control electrode are used for grounding, and corresponding pull-down resistors are respectively arranged on the line used for grounding of the control electrode of each switch tube; the control electrode of each fifth switch tube is also connected to the corresponding enable output terminal on the controller, and when the controller is powered on, each enable output port of the controller outputs a high-level signal.

[0013] As a further improvement to the inverting input terminal of each comparator, a corresponding first pull-up resistor is provided on a line of the inverting output terminal of each comparator for connecting to a power supply.

[0014] As a further improvement to the output end of each comparator, the output end of each comparator is also used to connect to a power supply, and corresponding second pull-up resistors are respectively arranged on corresponding lines of the output end of each comparator used to connect to the power supply.

[0015] As a further improvement to the fifth switch tubes, each of the fifth switch tubes is a triode.

[0016] As a further improvement to the switch tubes in the H-bridge motor driving circuit, the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are all MOS tubes.

[0017] A switch tube driving circuit includes a controller, a comparator and a state detection module; the inverting input end of the comparator is connected to the state detection module, the non-phase input end is connected to the control signal output interface of the controller, and the output end is used to connect to the control electrode of the driven switch tube;

[0018] The state detection module is used to detect whether the controller is in a power-on and / or reset state. When the controller is in a power-on and / or reset state, the state detection module sends a high potential signal to the inverting input terminal of the comparator, otherwise it sends a low potential signal to the inverting input terminal of the comparator.

[0019] As a further improvement to the status detection module, the status detection module includes a switch tube; the anode of the switch tube is connected to the inverting input terminal of the comparator, the cathode and the control electrode are used for grounding, and a pull-down resistor is respectively arranged on the line of the switch tube control electrode used for grounding; the control electrode of the switch tube is also connected to the enable output terminal of the controller, and when the controller is powered on, the enable output port of the controller outputs a high-level signal.

[0020] As a further improvement to the comparator, a first pull-up resistor is provided on a line of the inverting input terminal of the comparator for connecting to a power supply.

[0021] As a further improvement to the comparator, the output end of the comparator is also used to connect to a power supply, and a second pull-up resistor is provided on a corresponding line of the comparator output end for connecting to the power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural principle diagram of an H-bridge driving circuit in the prior art;

[0023] Figure 2 It is a structural principle diagram of an H-bridge driving circuit in an embodiment of a motor driving circuit;

[0024] Figure 3 4 is a driving circuit diagram of the first MOS tube Q1 in the H-bridge driving circuit in the motor driving circuit embodiment. DETAILED DESCRIPTION

[0025] The object of the present invention is to provide a motor drive circuit and a switch tube drive circuit thereof, which are used to solve the problem that in the existing switch tube control circuit, when the controller is powered on or reset, the controller pin is in the input state, causing the switch tube on the same side of the H-bridge drive circuit to be turned on, thereby causing the H-bridge drive circuit to have poor safety.

[0026] To achieve the above purpose, the technical solution provided by the present invention is:

[0027] A motor drive circuit comprises a controller and an H-bridge motor drive circuit composed of a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the control electrode of each switch tube is respectively provided with a corresponding switch tube drive circuit;

[0028] Among the switch tubes on the same side of the H-bridge motor drive circuit, the drive circuit of at least one switch tube is an anti-malfunction switch tube drive circuit;

[0029] Each anti-malfunction switch tube driving circuit includes a corresponding comparator and a state detection module, the inverting input end of each comparator is connected to the corresponding state detection module, the non-phase input end is connected to the corresponding control signal output interface on the controller, and the output end is connected to the control electrode of the corresponding switch tube in the H-bridge motor driving circuit;

[0030] The state detection module is used to detect whether the controller is in a power-on and / or reset state; when the controller is in a power-on and / or reset state, the state detection module sends a high potential signal to the inverting input terminal of the corresponding comparator, otherwise it sends a low potential signal to the inverting input terminal of the corresponding comparator.

[0031] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0032] Motor drive circuit embodiment:

[0033] This embodiment provides a motor drive circuit, which uses an H-bridge drive circuit composed of MOS tubes to drive the motor, and when the controller is powered on or reset, the MOS tubes on the same side will not be turned on at the same time due to the influence of interference signals.

[0034] The motor drive circuit provided in this embodiment has a structure as follows: Figure 2 As shown, it includes a controller U1 and an H-bridge driving circuit composed of a first MOS transistor Q1, a second MOS transistor Q2, a third MOS transistor Q3 and a fourth MOS transistor Q4. The H-bridge driving circuit is connected to the motor M1 to drive the motor M1.

[0035] Each MOS tube is provided with a corresponding MOS tube driving circuit. The driving circuit of at least one switch tube on the same side of the H-bridge motor driving circuit is an anti-malfunction switch tube driving circuit. Figure 2 In the embodiment, the first MOS tube Q1 and the third MOS tube Q3 are on the same side, and the second MOS tube Q2 and the fourth MOS tube Q4 are on the same side, then at least one of the first MOS tube Q1 and the third MOS tube Q3 has a driving circuit that is an anti-malfunction switch tube driving circuit, and at least one of the second MOS tube Q2 and the fourth MOS tube Q4 has a driving circuit that is an anti-malfunction switch tube driving circuit. In this embodiment, the driving circuit of the first MOS tube Q1 is described as an anti-malfunction switch tube driving circuit.

[0036] The driving circuit of the first MOS tube Q1 is as follows Figure 3 As shown, it includes a transistor Q5 and a comparator U2, the first enable terminal on the controller U1 is connected to the base of the transistor Q5 through a resistor R1, and the base of the transistor Q5 is also grounded through a pull-down resistor R2; the emitter of the transistor Q5 is grounded, the collector is connected to the power supply Vbat, and resistors R3 and R4 are arranged in series on the line where the collector of the transistor Q5 is connected to the power supply Vbat. The non-phase input terminal of the comparator U2 is connected to the first control signal output terminal of the controller, the inverting input terminal is connected to the connection point of the resistor R3 and the resistor R4, the output terminal is connected to the control electrode of the first MOS tube Q1, and in order to ensure the driving effect of the first MOS tube Q1, the output terminal of the comparator U2 is also connected to the power supply Vbat through a pull-up resistor R5.

[0037] The first enable terminal of the controller U1 refers to a port on the controller U1 for sending an enable signal for driving the first MOS tube Q1. When the controller U1 is powered on and / or reset, the potential of the port is pulled down by the resistor R1 and the resistor R2 to a low potential. When the controller U1 is powered on and / or reset, a high potential signal is output.

[0038] The first control signal output terminal of the controller U1 refers to a port on the controller U1 for sending a control signal for driving the first MOS transistor Q1. In this embodiment, the first control signal output terminal of the controller U1 outputs a PWM wave signal.

[0039] In this embodiment, the method for the controller U1 to drive the first MOS transistor Q1 is:

[0040] When the controller U1 is in a power-on and / or reset state, under the action of the resistor R1 and the resistor R2, the potential of the first enable terminal of the controller U1 is pulled down, at this time, the potential of the base of the transistor Q5 is low, the transistor Q5 is in a turned-off state, and the inverting input terminal of the comparator U2 is high level. Even if the non-inverting input terminal of the comparator U2 is high level, the signal output by its output terminal is also a low level signal, and the first MOS transistor Q1 will not be triggered to turn on, thereby avoiding the phenomenon that the MOS transistors on the same side are turned on at the same time in the H-bridge drive circuit when the controller U1 is powered on and / or reset;

[0041] When the controller U1 is powered on and / or reset and is in normal working state, the first enable terminal outputs a high potential signal. At this time, the base of the transistor Q5 is at a high potential, the transistor Q5 is triggered to be turned on, and the potential of the inverting input terminal of the comparator U2 is pulled low. At this time, the signal output by the output terminal of the comparator U2 is the same as the control signal output by the first control signal output terminal of the controller U1. Under the action of the pull-up resistor R5, the first MOS tube Q1 works according to the control signal output by the first control signal output terminal of the controller U1.

[0042] In this embodiment, the switch tube in the H-bridge driving circuit is a MOS tube; as other implementations, the switch tube in the H-bridge driving circuit can be other fully controlled switch devices such as triodes, field effect tubes, etc.

[0043] The fifth switch tube in this embodiment is a transistor Q5. As other implementations, the fifth switch tube may be other fully-controlled switch devices such as a MOS tube, a field effect tube, etc.

[0044] Switch tube driving circuit embodiment:

[0045] This embodiment provides a switch tube driving circuit, which is the same as the MOS tube driving circuit of the H-bridge driving circuit in the above motor driving circuit embodiment. The driving circuit has been described in detail in the above motor driving circuit embodiment and will not be further described here.

Claims

1. A motor drive circuit, comprising a controller, and an H-bridge motor drive circuit composed of a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the control electrode of each switch tube is respectively provided with a corresponding switch tube drive circuit; It is characterized in that Among the switch tubes on the same side of the H-bridge motor drive circuit, the drive circuit of at least one switch tube is an anti-malfunction switch tube drive circuit; the anti-malfunction switch tube drive circuit is used to prevent the switch tubes on the same side from being turned on at the same time due to the influence of interference signals when the controller is powered on or reset; Each anti-malfunction switch tube driving circuit includes a corresponding comparator and a state detection module, the inverting input end of each comparator is connected to the corresponding state detection module, the non-phase input end is connected to the corresponding control signal output interface on the controller, and the output end is connected to the control electrode of the corresponding switch tube in the H-bridge motor driving circuit; Each state detection module includes a corresponding fifth switch tube; the fifth switch tube is a triode, the collector of each fifth switch tube is connected to the inverting input terminal of the corresponding comparator, the emitter and the base are used for grounding, and a corresponding pull-down resistor is respectively arranged on the line of the base of each fifth switch tube for grounding; the base of each fifth switch tube is also connected to the corresponding enable output terminal of the controller, and when the controller is powered on, each enable output port of the controller outputs a high level signal; The state detection module is used to detect whether the controller is in a power-on and / or reset state; when the controller is in a power-on and / or reset state, the state detection module sends a high potential signal to the inverting input terminal of the corresponding comparator, otherwise it sends a low potential signal to the inverting input terminal of the corresponding comparator.

2. A motor drive circuit according to claim 1, It is characterized in that A corresponding first pull-up resistor is arranged on a line of the inverting input terminal of each comparator for connecting to a power supply.

3. A motor drive circuit according to claim 2, It is characterized in that The output end of each comparator is also used to connect to a power supply, and corresponding second pull-up resistors are respectively arranged on corresponding lines of the output end of each comparator used to connect to the power supply.

4. The motor drive circuit according to claim 1, It is characterized in that The first switch tube, the second switch tube, the third switch tube and the fourth switch tube are all MOS tubes.

5. A switch tube driving circuit, used to drive at least one switch tube on the same side of an H-bridge motor driving circuit, It is characterized in that The switch tube driving circuit includes a controller, a comparator and a state detection module; the switch tube driving circuit is used to avoid the simultaneous conduction of the same-side switches due to the influence of interference signals when the controller is powered on or reset; the inverting input end of the comparator is connected to the state detection module, the non-phase input end is connected to the control signal output interface of the controller, and the output end is used to connect the control electrode of the driven switch tube; the state detection module includes a corresponding switch tube; the switch tube is a triode, the collector of the switch tube is connected to the inverting input end of the corresponding comparator, the emitter and the base are used for grounding, and corresponding pull-down resistors are respectively arranged on the line of the switch tube base for grounding; the base of the switch tube is also connected to the corresponding enable output end of the controller, and when the controller is powered on, each enable output port of the controller outputs a high-level signal; The state detection module is used to detect whether the controller is in a power-on and / or reset state. When the controller is in a power-on and / or reset state, the state detection module sends a high potential signal to the inverting input terminal of the comparator, otherwise it sends a low potential signal to the inverting input terminal of the comparator.

6. A switch tube driving circuit according to claim 5, It is characterized in that The inverting input terminal of the comparator is used to connect the power supply line and is provided with a first pull-up resistor.

7. The switch tube driving circuit according to claim 6, It is characterized in that The output terminal of the comparator is also used to connect to a power supply, and a second pull-up resistor is arranged on a corresponding line of the comparator output terminal for connecting to the power supply.

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