A power output conversion drive circuit, a DC motor and an electrical appliance

Abstract

An embodiment of the present disclosure provides a power output conversion drive circuit, a DC motor, and an electrical appliance. The drive circuit is used to be electrically connected to the DC motor to provide a drive voltage for it, and includes: a P-channel field-effect transistor, whose gate obtains a control voltage and whose source outputs the drive voltage; an N-channel field-effect transistor, whose gate is connected to an input voltage, whose source is electrically connected to a resistor, and whose drain is electrically connected to the field-effect transistor; a push-pull circuit, which is electrically connected to the field-effect transistor through a zener diode, outputs the control voltage and is electrically connected to the gate of the P-channel field-effect transistor. It can achieve floating drive, enabling the bridge arm output to operate at a 100% duty cycle.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power output driving, and particularly to a power output conversion driving circuit, a DC motor, and an electrical appliance. Background Art

[0002] The power output conversion of a DC motor driving circuit is mainly completed by a half-bridge circuit. The half-bridge circuit uses a field effect transistor for power output conversion. The source of the upper transistor of the half-bridge is the output terminal, and a driving voltage is input to the gate-source of the upper transistor to control the on and off of the field effect transistor, thereby realizing power output conversion.

[0003] The existing half-bridge circuit uses a bootstrap circuit to generate the above driving voltage. The bootstrap circuit requires a dedicated driving circuit and cannot work at a 100% duty cycle; while using an additional charge pump circuit can make it work at a 100% duty cycle, however, it will make the circuit structure complex and the cost high. Summary of the Invention

[0004] Therefore, the embodiments of the present disclosure provide a power output conversion driving circuit, a DC motor, and an electrical appliance, which can achieve floating driving and make the bridge arm output work at a 100% duty cycle.

[0005] On the one hand, the embodiments of the present disclosure provide a power output conversion driving circuit, which is used to be electrically connected to a DC motor and provide a driving voltage for it, including: a P-channel field effect transistor, whose gate obtains a control voltage and whose source output is the driving voltage; an N-channel field effect transistor, whose gate is connected to an input voltage, whose source is electrically connected to a resistor, and whose drain is electrically connected to the field effect transistor; a push-pull circuit, which is electrically connected to the field effect transistor through a zener diode, outputs the control voltage and is electrically connected to the gate of the P-channel field effect transistor.

[0006] In a specific embodiment, the push-pull circuit includes: two triodes connected in parallel, and the gate of the P-channel field effect transistor is electrically connected between the two; the two triodes are used to increase the current of the control voltage.

[0007] In a specific embodiment, the field effect transistor is a junction field effect transistor.

[0008] In a specific embodiment, after the input voltage rises and reaches the turn-on voltage of the N-channel field effect transistor, the N-channel field effect transistor conducts and works in the amplification region; wherein, the drain-source current of the N-channel field effect transistor is greater than or equal to the sum of the drain-source current of the junction field effect transistor and the minimum working current of the zener diode.

[0009] In a specific embodiment, after the input voltage rises and reaches the turn-on voltage of the N-channel field-effect transistor, the N-channel field-effect transistor conducts and operates in the amplification region; the push-pull circuit charges the capacitor between the gate and source electrodes of the P-channel field-effect transistor, and the P-channel field-effect transistor conducts.

[0010] In a specific embodiment, the gate-source voltage V GSQ3 of the P-channel field-effect transistor and the regulated voltage value V Dz1 of the zener diode have the following relationship: V GSQ3 = V Dz1 ; the V Dz1 is greater than the turn-on voltage of the P-channel field-effect transistor.

[0011] In a specific embodiment, when the input voltage decreases, the N-channel field-effect transistor turns off, the gate-source of the P-channel field-effect transistor discharges through the push-pull circuit, the P-channel field-effect transistor turns off, and the drive voltage is 0.

[0012] On the other hand, a DC motor provided by an embodiment of the present disclosure includes: the power output conversion driver circuit described in any one of the above embodiments; a motor body electrically connected to the DC motor.

[0013] In yet another aspect, an electrical appliance provided by an embodiment of the present disclosure has the DC motor described in any one of the above embodiments.

[0014] In summary, each of the above embodiments of the present application may have one or more of the following advantages or beneficial effects: i) Using a push-pull circuit to drive the P-channel field-effect transistor can achieve 100% duty cycle output; ii) No dedicated charge pump circuit is required, and the circuit structure is simple; iii) The circuit can adapt to different bus voltages. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a circuit connection diagram of the power output conversion drive circuit provided by the first embodiment of the present disclosure;

[0017] Figure 2 It is a module connection diagram of the DC motor provided by the second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts belong to the scope of protection of the present disclosure.

[0019] Compared with the existing method of generating a floating drive voltage using a bootstrap circuit, which requires a dedicated drive circuit, the embodiment of the present disclosure uses a small number of discrete devices to form a power output conversion drive circuit for driving the P-channel field effect transistor of the half-bridge output circuit, which can operate at a 100% duty cycle, has a simple circuit structure, and good measured effects, and is worthy of popularization and application.

[0020]

First Embodiment

[0021] See Figure 1 , which is a power output conversion drive circuit provided by the first embodiment of the present disclosure. Among them, the P-channel field effect transistor Q3 is the power output part of the half-bridge output circuit, and its front-stage connection is the drive circuit.

[0022] The drive circuit includes a plurality of discrete devices. Specifically, it includes an N-channel field effect transistor Q1 for boosting, which is connected to a push-pull circuit through a voltage regulator diode D Z1 connection push-pull circuit.

[0023] Among them, the gate of the N-channel field effect transistor Q1 is connected to the input voltage V IN , the drain of the N-channel field effect transistor Q1 is electrically connected to the push-pull circuit through a voltage regulator diode D Z1 ; the push-pull circuit outputs a control voltage and is electrically connected to the gate of the P-channel field effect transistor, and the source of the P-channel field effect transistor is electrically connected to the DC motor. The P-channel field effect transistor is connected to the control voltage and outputs a corresponding drive voltage at the source according to the control voltage to drive the DC motor.

[0024] Among them, a field effect transistor, specifically a junction field effect transistor, is also connected between the drain of the N-channel field effect transistor Q1 and the voltage regulator diode DZ1 to achieve constant current. The source of the N-channel field effect transistor Q1 is also electrically connected to a resistor R1.

[0025] Combined with Figure 1 It can be known that the gate-source voltage of the N-channel field effect transistor Q1 satisfies the formula: V GSQ1 =V IN -I DSQ1 *R1; where I DSQ1 is the drain-source current of the N-channel field effect transistor Q1.

[0026] Among them, the push-pull circuit includes two triodes, and the gate of the P-channel field-effect transistor is electrically connected between the two; the two triodes are used to increase the current of the control voltage; the bases of the two triodes are both electrically connected to the drain of the N-channel. The collector of the first triode T1 is electrically connected to the positive power supply and the drain of the P-channel field-effect transistor, the emitter of the first triode T1 is connected to the emitter of the second triode T2, and the collector of the second triode T2 is electrically connected to the resistor R1 and the negative power supply; the output between the emitter of the first triode T1 and the emitter of the second triode T2 is the control voltage and is electrically connected to the gate of the P-channel field-effect transistor Q3.

[0027] The working principle of this drive circuit is as follows:

[0028] When the input voltage V IN rises to a high level, as V IN rises, before the N-channel field-effect transistor Q1 is turned on, its drain-source current I DSQ1 is 0. According to the above formula, its gate-source voltage V GSQ1 = V IN , and V GSQ1 rises as V IN rises.

[0029] When V GSQ1 rises to the turn-on voltage of the N-channel field-effect transistor Q1 as V IN rises, the field-effect transistor Q1 starts to conduct, and the current I DSQ1 of the drain-source of Q1 starts to increase, and the voltage of R1 starts to increase. According to the above formula, V GSQ1 cannot follow V IN and keep increasing, but makes the field-effect transistor Q1 work in the amplification region to reach dynamic equilibrium. At this time, the drain-source current of the field-effect transistor Q1 is: I DSQ1 = (V IN - V GSON ) / R1.

[0030] When the field-effect transistor Q1 is conducting, the gate-source voltage V GSQ2 of the junction field-effect transistor Q2 is 0, so the current passing through the drain-source of the transistor Q2 is a constant value. Therefore, the transistor Q2 can achieve the function of constant current.

[0031] Among them, the drain-source current of the field-effect transistor Q1 is at least equal to the sum of the drain-source current of the transistor Q2 and the minimum current of the voltage regulator diode DZ1 working; otherwise, it will cause the working current of the voltage regulator diode DZ1 to be insufficient and the voltage regulator diode DZ1 cannot regulate the voltage normally. At this time, the voltage of the base of the first triode T1 is V HSubtracting the regulated voltage value of the voltage regulator diode DZ1, the capacitor between the gate and source of the P-channel field-effect transistor Q3 is charged through the push-pull circuit composed of two triodes T1 and T2. The voltage between the gate and source of the P-channel field-effect transistor Q3 is: V GSQ3 = -V DZ1 .

[0032] At this time, the P-channel field-effect transistor Q3 is turned on, and the output control voltage V OUT is the bus voltage minus the conduction voltage drop of the field-effect transistor Q3. Since V GSQ3 has to be greater than the conduction voltage of the field-effect transistor Q3, the voltage regulator diode DZ1 is generally selected as a 12V voltage regulator diode. Among them, the bus voltage is Figure 1 the voltage output by the power supply in

[0033] When the input voltage VIN drops to a low level, the field-effect transistor Q1 is turned off. At this time, the charge on the gate-source of the field-effect transistor Q3 discharges through the first triode T1 until the voltage between the gate-source of the field-effect transistor Q3 is less than its turn-on voltage, then the field-effect transistor Q3 is turned off, and no drive voltage is output, or the drive voltage V OUT is 0.

[0034] Next, the constant current function of the junction field-effect transistor in the above drive circuit will be described in detail.

[0035] Connect the gate and source of the transistor Q2 together to be used as a constant current source, that is, when V GSQ2 = 0, the current flowing through the drain-source of the transistor Q2 is constant; at this time, the drain-source current of the transistor Q2 cannot be too large. If the drain-source current is too large, under the condition of satisfying the conduction of the field-effect transistor Q1, the resistance value of R1 needs to be reduced, which will lead to an increase in the power consumption of the resistor R1. When the field-effect transistor Q1 is working, the voltage of the resistor R1 is constant, and this voltage is the input voltage V IN minus the turn-on voltage of the transistor Q2. Then the power consumption of the resistor R1 is: P1 = (V IN - V GSINQ1 ) 2 / R1.

[0036] Therefore, while satisfying the power consumption of the resistor R1, the transistor Q2 should be selected with a larger current model, so as to ensure that there is enough current at the base of the first triode T1, and through the amplification of the first triode TI, to ensure that the gate-source of the field-effect transistor Q3 can discharge quickly to reduce the turn-off loss.

[0037] This drive circuit uses a push-pull circuit to drive the P-channel field-effect transistor Q3, simplifies the structure of the drive circuit, and does not require a dedicated charge pump circuit, capable of achieving 100% duty cycle output. Specifically, when the input voltage VIN rises to turn on the field-effect transistor Q1, the zener diode DZ1 works normally, and the gate of the field-effect transistor Q3 is charged through the second triode T2. When the gate-source voltage of Q3 reaches -V DZ1 , the field-effect transistor Q3 conducts, and the output drive voltage V OUT is the bus voltage. Therefore, as long as the control input voltage V IN is at a high level, it can ensure that the above drive voltage V OUT is maintained at the bus voltage, that is, 100% duty cycle output.

[0038] The current passing through the drain-source of the junction field-effect transistor Q2 is used to control the base current of the triode in the push-pull circuit. After amplification by the triode, it is ensured that the gate-source of the P-channel field-effect transistor Q3 can be charged and discharged quickly to reduce the switching loss. The charging circuit of the gate-source of the field-effect transistor Q3 is: the gate of the field-effect transistor Q3, the emitter of the second triode T2, the collector of the first triode T1, and the ground. Therefore, to accelerate the charging speed of the gate-source of the field-effect transistor Q3, the following means are included: 1) The base current of the second triode T2 can be increased, that is, a larger constant-current junction field-effect transistor is selected for the transistor Q2; 2) The amplification factor of the second triode T2 is increased.

[0039] The discharge circuit of the gate-source of the field-effect transistor Q3 is: the gate of the field-effect transistor Q3, the emitter of the first triode T1, and the voltage VH. The same as the above charging principle, to accelerate the discharge of the gate-source of the field-effect transistor Q3, the following means are included: 1) Increase the base current of the first triode T1, 2) Increase the amplification factor of the first triode T1.

[0040] Through the resistor R1 connected to the source of the field-effect transistor Q1, the field-effect transistor Q1 works in the amplification region, can dynamically adjust the voltage drop across its own drain-source, and can adapt to different bus voltages. However, the bus voltage needs to be greater than or equal to the sum of the regulated voltage value of the voltage regulator DZ1 and the voltage drop across the resistor R1. For example, when VH increases from low to high, since the regulated voltage value of the voltage regulator DZ1 remains unchanged, the drain-source voltage drop of the field-effect transistor Q1 increases, so the current flowing through the drain-source of the MOS switch Q1 starts to increase, and the voltage drop across the resistor R1 starts to increase; this will cause the gate-source voltage of the field-effect transistor Q1 to decrease, and the on-resistance of the field-effect transistor Q1 to increase, until it reaches a stable state, that is:

[0041]

[0042] Among them, when the bus voltage is relatively high, the voltage drop across the drain-source of the field-effect transistor Q1 is relatively large, resulting in relatively large losses. Therefore, a field-effect transistor Q1 with a relatively large dissipation power should be selected to improve the reliability of the circuit.

[0043]

Second Embodiment

[0044] The second embodiment of the present disclosure provides a DC motor driver. The driver has the power output conversion drive circuit as described in the first embodiment above, which is used to electrically connect to a DC motor and drive the DC motor to operate, specifically for driving the DC motor to convert power output.

[0045]

Third Embodiment

[0046] Refer to Figure 2 , which is a DC motor provided by the third embodiment of the present disclosure. The DC motor includes, for example, a motor body and the driver as described in the second embodiment or the power output conversion drive circuit as described in the first embodiment. Among them, the driver is electrically connected to the motor body to control its output of different powers.

[0047]

Fourth Embodiment

[0048] The fourth embodiment provides an electrical appliance, which has the DC motor as described in the third embodiment above. It can be a common household electrical appliance or an industrial electrical appliance.

[0049] On the other hand, the electrical appliance can also be a controller or a remote control with the driver as described in the second embodiment above, which is used to drive the target DC motor to perform power conversion actions.

[0050] In several embodiments provided by the present disclosure, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the couplings or direct couplings or communication connections shown or discussed with each other can be indirect couplings or communication connections through some interfaces, devices, or units, and can be in electrical, mechanical, or other forms.

[0051] The units described as separate components may or may not be physically separated. The components shown as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0052] In addition, in each embodiment of the present disclosure, each functional unit can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware, or in the form of a combination of hardware and software functional units.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present disclosure.

Claims

1. A power output conversion driving circuit, characterized in that The driving circuit is used for electrically connecting a DC motor and providing a driving voltage thereto, and includes an N-channel field effect transistor, a field effect transistor, a zener diode, a push-pull circuit, a P-channel field effect transistor, and a power supply; For the P-channel field effect transistor, its gate obtains a control voltage; the source of the P-channel field effect transistor is connected to the DC motor, and the output is the driving voltage; For the N-channel field effect transistor, its gate is connected to an input voltage, its source is electrically connected to one end of a resistor, and its drain is electrically connected to the field effect transistor; the other end of the resistor is connected to the negative electrode of the power supply and grounded; The push-pull circuit is electrically connected to the field effect transistor through the zener diode, outputs the control voltage and is electrically connected to the gate of the P-channel field effect transistor; The push-pull circuit includes a first triode and a second triode. The bases of the first triode and the second triode are both connected to the drain of the N-channel field effect transistor; the emitters of the first triode and the second triode are both connected to the gate of the P-channel field effect transistor; the collector of the first triode is connected to the drain of the P-channel field effect transistor and the positive electrode of the power supply, and the collector of the second triode is connected to the negative electrode of the power supply; The gate and the source of the field effect transistor are connected and connected to the drain of the N-channel field effect transistor. The negative electrode of the zener diode is connected to the drain of the field effect transistor and the collector of the first triode. The positive electrode of the zener diode is connected to the drain of the N-channel field effect transistor and the base of the first triode; The gate-source voltage V of the P-channel field effect transistor GSQ3 and the regulated voltage value V of the zener diode Dz1 have the relationship: V GSQ3 = V Dz1 ; The V Dz1 is greater than the turn-on voltage of the P-channel field effect transistor.

2. The power output conversion driving circuit according to claim 1, characterized in that The field effect transistor is a junction field effect transistor.

3. The power output conversion driving circuit according to claim 2, wherein After the input voltage rises and reaches the turn-on voltage of the N-channel field effect transistor, the N-channel field effect transistor conducts and operates in the amplification region; Wherein, the drain-source current of the N-channel field effect transistor is greater than or equal to the sum of the drain-source current of the junction field effect transistor and the minimum operating current of the zener diode.

4. The power output conversion driving circuit according to claim 2, wherein After the input voltage rises and reaches the turn-on voltage of the N-channel field effect transistor, the N-channel field effect transistor conducts and operates in the amplification region; The push-pull circuit charges the capacitor between the gate and the source of the P-channel field effect transistor, and the P-channel field effect transistor conducts.

5. The power output conversion driving circuit according to claim 2, characterized in that, When the input voltage decreases, the N-channel field effect transistor turns off, the gate-source of the P-channel field effect transistor discharges through the push-pull circuit, the P-channel field effect transistor turns off, and the driving voltage is 0.

6. A DC motor, characterized in that, Comprising: The power output conversion driving circuit according to any one of claims 1-5; A motor body, electrically connected to the power output conversion driving circuit.

7. An electrical appliance, characterized in that, Having a DC motor as claimed in claim 6.

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