H-bridge driving circuit with discharge branch and chip

Abstract

The utility model relates to an H-bridge driving circuit with a discharge branch and a chip, and belongs to the field of motor driving. The driving circuit comprises a driving chip module, a switch control module and a switch misconduction protection module. The switch control module is composed of a triode and MOS tube combined control circuit, it is ensured that grid charges can be rapidly discharged when the IGBT is turned off, and misconduction is prevented. The misconduction protection module enhances the charge discharge capability by providing a low-impedance path, ensures the accurate turn-off of the IGBT, and avoids the influence of surge voltage. The circuit realizes reliability and quick response performance in forward and reverse control and high-frequency switch application of the motor, and is suitable for direct-current motor control, stepping motor control, direct-current-alternating-current converters, direct-current-direct-current converters and other power electronic devices. Through the design, the stability and the safety of the motor control system are effectively improved.

Description

Technical Field

[0001] The utility model relates to the field of motor driving, in particular to an H-bridge driving circuit with a discharge branch and a chip. Background Art

[0002] The H-bridge circuit is a common motor drive circuit used in motor drive circuits. It reverses the voltage or current across the connected load or output terminals. This type of circuit can be used for forward and reverse control of DC motors, speed control, stepper motor control, most DC-AC converters (such as inverters and frequency converters) used in power conversion, some DC-DC converters (push-pull converters), and other power electronic devices. An H-bridge typically consists of four independently controlled switching elements, such as an H-bridge circuit consisting of four IGBTs.

[0003] An H-bridge circuit composed of IGBTs (Integrated Gate Bipolar Transistors) controls the direction of the load current by switching the IGBTs symmetrically. The faster the current direction changes, the higher the circuit's operating frequency and the faster the IGBTs switch. During high-speed switching, the parasitic inductance of the IGBTs, delays in the drive circuit, and load variations can cause the IGBTs to turn on incorrectly or not turn off completely.

[0004] Patent publication number CN110350771A discloses a charge release mechanism using a transistor between the gate and ground, which, to a certain extent, eliminates the risk of mis-turning on or incompletely shutting down the IGBT. This control method offers advantages in circuit simplicity and low cost. However, directly using resistors or transistors to release gate charge in an H-bridge drive circuit limits the charge release rate and poses a risk when surge voltages are present. Utility Model Content

[0005] The utility model provides an H-bridge drive circuit and chip with a discharge branch. The module can more accurately discharge the gate charge and avoid mis-conduction of the switch tube. When applied to high-frequency circuits, it can cooperate with the system to transmit high-speed switching signals, ensuring the reliability of IGBT in high-frequency switching applications.

[0006] In order to achieve the purpose of this utility model, the present invention adopts the following scheme:

[0007] An H-bridge drive circuit with a discharge branch, characterized in that it includes two bridge arms, each of which is provided with two switch units, and the control end of each switch unit is connected to its corresponding independent drive circuit; each drive circuit includes a drive chip module and a switch control module; the switch control module includes a first drive branch and a second drive branch; the first drive branch and the second drive branch are both control circuits composed of a combination of a triode and a MOS transistor, and the first drive branch and the second drive branch are arranged in parallel and connected to the control end of the switch unit, for controlling the switching of the switch unit and discharging the charge at the control end of the switch unit.

[0008] Furthermore, the driver chip module includes a driver chip for receiving and amplifying the control signal and a second resistor;

[0009] The driver chip also includes a power pin VDD connected to the positive pole of the power supply, a power pin GND connected to the negative pole of the power supply, a control signal input end and an output end. The output end of the driver chip is connected to one end of the second resistor, and the other end of the second resistor is the control signal output end of the driver chip module.

[0010] Furthermore, the first driving branch includes a first resistor, a first triode, a first MOS transistor, a first voltage regulator transistor and a fifth resistor;

[0011] The emitter of the first transistor is connected to the positive electrode of the power supply and one end of the first resistor, the base of the first transistor is connected to the other end of the first resistor and the control signal output end of the driver chip module, and the collector of the first transistor is connected to the gate of the first MOS transistor and the positive electrode of the first voltage regulator tube; the source of the first MOS transistor is connected to the positive electrode of the power supply and the negative electrode of the first voltage regulator tube, and the drain is connected to one end of the fifth resistor; the other end of the fifth resistor is connected to the control end of the switch unit.

[0012] Preferably, the first transistor is a PNP transistor; the first MOS transistor is a PMOS transistor.

[0013] Furthermore, the charge discharge branch includes a second voltage regulator tube, a third resistor, a second triode, a second MOS tube, a fourth resistor, a sixth resistor, an eighth resistor, a TVS tube and a switch mis-conduction protection module;

[0014] The emitter of the second triode is connected to the positive electrode of the power supply and the negative electrode of the second voltage regulator tube, the base of the second triode is connected to the positive electrode of the second voltage regulator tube, one end of the third resistor and the control signal output end of the driving chip module, the collector of the second triode is connected to one end of the eighth resistor, one end of the fourth resistor, the gate of the second MOS tube and one end of the TVS tube; the other end of the third resistor is connected to the negative electrode of the power supply; the other end of the fourth resistor is connected to the negative electrode of the power supply; the other end of the eighth resistor is grounded; the source of the second MOS tube is connected to the negative electrode of the power supply, the drain of the second MOS tube is connected to the other end of the TVS tube and one end of the sixth resistor; the other end of the sixth resistor is connected to the control end of the switch unit; the switch misconduct protection module is connected to the control end of the switch unit.

[0015] Preferably, the second transistor is a PNP transistor; the second MOS transistor; and the TVS transistor is a bidirectional TVS transistor.

[0016] Furthermore, the IGBT mis-conduction protection module includes a first diode, a second diode, and a seventh resistor;

[0017] One end of the seventh resistor is connected to the control end of the switch unit and the positive electrode of the first diode, and the other end of the seventh resistor is connected to the negative electrode of the power supply; the negative electrode of the second diode is connected to the negative electrode of the first diode, and the positive electrode of the second diode is connected to the negative electrode of the power supply.

[0018] Preferably, the bridge arm includes a first bridge arm and a second bridge arm, and each bridge arm is provided with two switch units, and the switch unit includes an upper bridge arm switch unit and a lower bridge arm switch unit connected in series; one end of the upper bridge arm switch unit of the first bridge arm is connected to the positive pole of the power supply, and the other end is connected to one end of the lower bridge arm switch unit of the first bridge arm and one end of the inductor; the other end of the inductor is connected to one end of the load resistor; the other end of the lower bridge arm switch unit of the first bridge arm is connected to the negative pole of the power supply; one end of the upper bridge arm switch unit of the second bridge arm is connected to the positive pole of the power supply, and the other end is connected to one end of the lower bridge arm switch unit of the second bridge arm and the other end of the load resistor; the other end of the lower bridge arm switch unit of the second bridge arm is connected to the negative pole of the power supply.

[0019] Preferably, the switch unit includes a fast thyristor, a gate turn-off thyristor (GTO), a power transistor (GTR), a power field effect transistor (MOSFET) or an insulated gate transistor (IGBT).

[0020] The utility model also discloses a chip integrated with the motor controller with the discharge branch.

[0021] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0022] The utility model can quickly discharge the gate charge when the IGBT is turned off, and even if there is a surge voltage on the gate, the gate will be quickly lowered to protect the gate from breakdown, thereby enhancing the stability and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an H-bridge driving circuit diagram of an embodiment of the present utility model;

[0024] Figure 2 A circuit diagram of the drive circuit being turned on when the IGBT tube of the embodiment of the utility model is turned off;

[0025] Figure 3 This is a circuit diagram of the drive circuit when the IGBT tube is turned on in an embodiment of the utility model. DETAILED DESCRIPTION

[0026] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings. The exemplary embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein. On the contrary, these embodiments are provided to make the present invention more comprehensive and complete and to fully convey the concepts of the exemplary embodiments to those skilled in the art. The same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In this embodiment, the circuit diagram of the motor controller with the discharge branch is as follows: Figure 1 As shown, the first bridge arm and the second bridge arm of the H-bridge driving circuit respectively include two switching units. The MCU sends a control signal to the driving circuit through a PWM signal. By adjusting the control signal, the switching tubes in the symmetrical direction are turned on to control the direction of the load current.

[0029] In this embodiment, the switching units used in the bridge arms of the H-bridge drive circuit are insulated gate transistors (IGBTs). The upper arm switch unit of the first bridge arm is IGBT Q2, and the lower arm switch unit of the first bridge arm is IGBT Q1. The collector of IGBT Q2 is connected to the positive power supply VCC, and the emitter is connected to the collector of IGBT Q1; the emitter of IGBT Q1 is connected to the negative power supply. The upper arm switch unit of the second bridge arm is IGBT Q3, and the lower arm switch unit of the second bridge arm is IGBT Q4. The collector of IGBT Q3 is connected to the positive power supply VCC, and the emitter is connected to the collector of IGBT Q4; the emitter of IGBT Q4 is connected to the negative power supply. The emitter of IGBT Q2 is connected in series with inductor L1, then in series with load resistor RL, and then connected to the collector of IGBT Q4.

[0030] The power pin VDD of the driver chip U6 is connected to a 15V power supply, and the power pin GND is grounded. Driver chip U6 uses a differential input method to enhance the signal's anti-interference ability. In the differential signal input, the positive-phase input terminal IN+ and the negative-phase input terminal IN- together form a differential signal pair. The negative-phase input terminal IN- is grounded, and the positive-phase input terminal IN+ is connected to the control signal output port, forming a single-ended input. The function of driver chip U6 is to amplify the driving capability. The output terminal OUT of driver chip U6 is connected to a second resistor R2 for current limiting.

[0031] In this embodiment, since the driving circuits of the four IGBT tubes are the same, the driving circuit implementation of the IGBT tube Q1 is shown here, and the IGBT shutdown process is controlled as follows: Figure 2 As shown, the PWM signal input signal of the MCU is limited by the IO port level. The high-level output is generally within 1.8-5V, and the low-level output is around 0V.

[0032] The first driving branch and the second driving branch respectively include a triode switching circuit and a MOS tube switching circuit, and the triode switching circuit and the MOS tube switching circuit are cascaded to drive the output; the first driving branch and the second driving branch are arranged in parallel and connected to the control end of the switch unit; the first driving branch is used to control the conduction of the switch unit; the second driving branch is used to control the shutdown of the switch unit and is used to quickly discharge the charge at the control end of the switch unit when the switch switches from the on state to the off state.

[0033] In the first driving branch, when the PWM signal is at a low level, the output OUT of the driving chip U6 is at a low level, and after passing through the second resistor R2, it reaches the first transistor U1. The first transistor U1 is a PNP transistor. At this time, its emitter voltage is 15V and the base voltage is 0V. The first transistor U1 is turned on, and the power supply voltage of 15V is applied to the gate of the first MOS transistor U2. The first MOS transistor U2 is a P-type MOS transistor with a gate voltage of 15V and a source voltage of 15V. The first MOS transistor U2 is not turned on. At this time, in the second driving branch, the gate of the second transistor U3 is at a low level, the second transistor U3 is turned on, and the gate of the second MOS transistor U4 is 15V, and the second MOS transistor U4 is turned on. The MOS transistor is at V DS Under the condition of no change, V GS The higher the R DS The smaller it is, the smaller the time constant RC is. C is the equivalent capacitance of the IGBT gate and emitter. Through the transistor switching circuit, the gate voltage of the MOS tube switching circuit can be increased, thereby further reducing the on-resistance and accelerating the discharge.

[0034] Therefore, the negative voltage of the power supply -5V is connected to the gate of the IGBT tube Q1 through the second MOS tube U4 and the sixth resistor R6, forming a low-impedance path. The voltage at the gate of the IGBT tube Q1 is quickly pulled down to close to -5V. The IGBT tube Q1 is turned off, and its gate charge is quickly discharged to ground. The charge discharge branch ensures that the IGBT will not be mis-turned on or incompletely turned off when it is turned off, ensuring the reliability of the IGBT in high-frequency switching applications.

[0035] The process of controlling IGBT conduction is as follows Figure 3 As shown, when the PWM signal of the MCU is at a high level, the output OUT of the driver chip U6 is 15V. In the charge discharge branch, the gate voltage of the second transistor U3 is 15V, U3 is turned off, the gate voltage of the second MOS transistor U4 is 0V, and the second MOS transistor U4 is not conducting.

[0036] In the first drive branch, the base voltage of the first transistor U1 is 15V, and the emitter voltage is 15V, making the first transistor U1 non-conductive. The gate voltage of the first MOS transistor U2 is 0V, and the emitter voltage is 15V. Therefore, the second MOS transistor U4 is conductive, and the positive voltage of the power supply (15V) is connected to the gate of the IGBT Q1 via the fifth resistor R5. The gate voltage of the IGBT Q1 is 15V, and the IGBT Q1 is conductive.

[0037] In this embodiment, the switch mis-conduction protection module includes a first diode D1, a second diode D2, and a seventh resistor R7. One end of the seventh resistor R7 is connected to the gate of the IGBT Q1, and the other end is grounded. The anode of the first diode D1 is connected to the gate of the IGBT Q1, and the cathode is connected to the cathode of the second diode D2. The anode of the second diode D2 is connected to the negative terminal of the power supply. The switch mis-conduction protection module enhances charge discharge capability by providing a low-impedance path, ensuring rapid IGBT shutdown. The first and second diodes prevent current backflow and voltage rebound, protecting the IGBT Q1 from surge voltages.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An H-bridge drive circuit with a discharge branch, characterized in that: It includes two bridge arms, each of which is provided with two switch units, and the control end of each switch unit is connected to its corresponding independent driving circuit; each driving circuit includes a driving chip module and a switch control module; The switch control module includes a first driving branch and a second driving branch; The first driving branch and the second driving branch respectively include a triode switch circuit and a MOS tube switch circuit, and the triode switch circuit and the MOS tube switch circuit are cascaded to drive the output; the first driving branch and the second driving branch are arranged in parallel and connected to the control end of the switch unit; The first driving branch is used to control the conduction of the switch unit; the second driving branch is used to control the turn-off of the switch unit and to quickly discharge the charge at the control end of the switch unit when the switch switches from the on state to the off state.

2. The H-bridge driving circuit with a discharge branch according to claim 1, characterized in that: The driver chip module includes a driver chip for receiving and amplifying a control signal and a second resistor; The driver chip also includes a power pin connected to the positive pole of the power supply, a grounded power pin, a control signal input end and an output end. The output end of the driver chip is connected to one end of the second resistor, and the other end of the second resistor is the control signal output end of the driver chip module.

3. The H-bridge driving circuit with a discharge branch according to claim 1, characterized in that: The first driving branch includes a first resistor, a first triode, a first MOS transistor, a first voltage regulator transistor and a fifth resistor; The emitter of the first transistor is connected to the positive electrode of the power supply and one end of the first resistor, the base of the first transistor is connected to the other end of the first resistor and the control signal output end of the driver chip module, and the collector of the first transistor is connected to the gate of the first MOS transistor and the positive electrode of the first voltage regulator tube; The source of the first MOS tube is connected to the positive electrode of the power supply and the negative electrode of the first voltage regulator tube, and the drain is connected to one end of the fifth resistor; The other end of the fifth resistor is connected to the control end of the switch unit.

4. The H-bridge driving circuit with a discharge branch according to claim 3, characterized in that: The first transistor is a PNP transistor; the first MOS transistor is a PMOS transistor.

5. The H-bridge driving circuit with a discharge branch according to claim 1, characterized in that: The second driving branch includes a second voltage regulator tube, a third resistor, a second triode, a second MOS tube, a fourth resistor, a sixth resistor, an eighth resistor, a TVS tube and a switch mis-conduction protection module; The emitter of the second triode is connected to the positive electrode of the power supply and the negative electrode of the second voltage regulator tube, the base of the second triode is connected to the positive electrode of the second voltage regulator tube, one end of the third resistor and the control signal output end of the driver chip module, and the collector of the second triode is connected to one end of the eighth resistor, one end of the fourth resistor, one end of the TVS tube and the gate of the second MOS tube; The other end of the third resistor is connected to the negative electrode of the power supply; the other end of the fourth resistor is connected to the negative electrode of the power supply; the other end of the eighth resistor is grounded; The source of the second MOS tube is connected to the negative electrode of the power supply, and the drain of the second MOS tube is connected to the other end of the TVS tube and one end of the sixth resistor; The other end of the sixth resistor is connected to the control end of the switch unit; The switch mis-conduction protection module is connected to the control end of the switch unit.

6. The H-bridge driving circuit with a discharge branch according to claim 5, characterized in that: The second transistor is a PNP transistor; the second MOS transistor; and the TVS transistor is a bidirectional TVS transistor.

7. The H-bridge driving circuit with a discharge branch according to claim 5, characterized in that: The switch mis-conduction protection module includes a bidirectional TVS tube and a seventh resistor; One end of the seventh resistor is connected to the control end of the switch unit and one end of the bidirectional TVS tube, and the other end of the seventh resistor is connected to the negative electrode of the power supply; The other end of the bidirectional TVS tube is connected to the negative electrode of the power supply.

8. The H-bridge driving circuit with a discharge branch according to claim 1, characterized in that: The bridge arm includes a first bridge arm and a second bridge arm, each bridge arm is provided with two switch units, and the switch unit includes an upper bridge arm switch unit and a lower bridge arm switch unit connected in series; One end of the upper bridge arm switch unit of the first bridge arm is connected to the positive electrode of the power supply, and the other end is connected to one end of the lower bridge arm switch unit of the first bridge arm and one end of the inductor; the other end of the inductor is connected to one end of the load resistor; The other end of the lower bridge arm switch unit of the first bridge arm is connected to the negative electrode of the power supply; One end of the upper bridge arm switch unit of the second bridge arm is connected to the positive electrode of the power supply, and the other end is connected to one end of the lower bridge arm switch unit of the second bridge arm and the other end of the load resistor; The other end of the lower bridge arm switch unit of the second bridge arm is connected to the negative electrode of the power supply.

9. The H-bridge driving circuit with a discharge branch according to claim 8, characterized in that: The switch unit includes a fast thyristor, a gate turn-off thyristor (GTO), a power transistor (GTR), a power field effect transistor (MOSFET) or an insulated gate transistor (IGBT).

10. A chip, characterized in that: An H-bridge driving circuit with a discharge branch as claimed in any one of claims 1 to 9 is integrated.

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