CN209823402U - Motor reverse electromotive force switch protection circuit - Google Patents
Motor reverse electromotive force switch protection circuit Download PDFInfo
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- CN209823402U CN209823402U CN201921054031.XU CN201921054031U CN209823402U CN 209823402 U CN209823402 U CN 209823402U CN 201921054031 U CN201921054031 U CN 201921054031U CN 209823402 U CN209823402 U CN 209823402U
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Abstract
The utility model discloses a motor back electromotive force switch protection circuit, which comprises a MOS tube Q1, a triode Q2 and an amplifier U1; the drain of the MOS transistor Q1 is connected to the first power input terminal, the source of the MOS transistor Q1 is used as the first output terminal of the protection circuit, the source of the MOS transistor Q1 is further connected to the collector of the transistor Q2 through the series connection of the resistor R1 and the resistor R3, the emitter of the transistor Q2 is connected to the second power input terminal, the drain of the MOS transistor Q1 is further connected to the cathode of the diode D2 through the resistor R2, and the anode of the diode D2 is connected to the second power input terminal; the inverting input of the amplifier U1 is connected to the first output of the protection circuit through a resistor R5, and the inverting input of the amplifier U1 is also connected to the second output of the protection circuit through a resistor R7. The utility model discloses a protection circuit can be external alone, need not to integrate inside the motor power supply, flexibility greatly increased when selecting motor power supply.
Description
Technical Field
The utility model belongs to the technical field of the motor protection, concretely relates to reverse electromotive force switch protection circuit of motor.
Background
The power supply of the motor is usually a switching power supply, and when the motor works normally, the motor is a normal inductive load. When the motor encounters a specific condition and generates a deceleration or reverse running signal, a reverse electromotive force can be generated, and the electromotive force can cause the voltage at the power supply position of the motor to exceed the output voltage of the switching power supply at the moment, and can cause the damages of an output rectifier diode, an output filter electric kiln and the like of the switching power supply.
SUMMERY OF THE UTILITY MODEL
In view of this, the present invention provides a protection circuit that can be externally installed alone without being integrated into the power supply of the motor.
In order to achieve the above purpose, the utility model provides a following technical scheme:
the motor back electromotive force switch protection circuit comprises a MOS (metal oxide semiconductor) tube Q1, a triode Q2 and an amplifier U1;
the drain of the MOS transistor Q1 is connected to a first power input terminal, the source of the MOS transistor Q1 serves as a first output terminal of the protection circuit, the source of the MOS transistor Q1 is further connected to the collector of the transistor Q2 through the series connection of a resistor R1 and a resistor R3, the emitter of the transistor Q2 is connected to a second power input terminal, the drain of the MOS transistor Q1 is further connected to the cathode of a diode D2 through a resistor R2, and the anode of the diode D2 is connected to the second power input terminal;
the output end of the amplifier U1 is connected with the base of the triode Q2 through a resistor R6, the non-inverting input end of the amplifier U1 is connected with the cathode of a diode D2 through a resistor R4, the non-inverting input end of the amplifier U1 is also connected with the cathode of a diode D3, and the anode of the diode D3 is connected with a second power supply input end;
the inverting input of the amplifier U1 is connected to the first output of the protection circuit through a resistor R5, and the inverting input of the amplifier U1 is also connected to the second output of the protection circuit through a resistor R7.
Optionally, the protection circuit further includes a diode D1, and a cathode of the diode D1 is connected to the source of the MOS transistor Q1.
Optionally, the diode D1, the diode D2, and the diode D3 are all zener diodes.
Optionally, the protection circuit further includes a capacitor C, one end of the capacitor C is connected to the cathode of the diode D2, and the other end of the capacitor C is connected to the second power input end.
Optionally, a power supply terminal of the amplifier U1 is connected to the cathode of the diode D2, and a ground terminal of the amplifier U1 is connected to the second power supply input terminal.
Optionally, the MOS transistor Q1 is a P-channel MOS transistor.
The beneficial effects of the utility model reside in that: compare with traditional motor back electromotive force protection circuit, the utility model discloses a protection circuit can be external alone, need not to integrate inside the motor power supply, flexibility greatly increased when selecting the motor power supply, and output voltage, the suitable switching power supply of power are increasing the utility model discloses a can directly regard as the motor power supply to use behind the protection circuit.
Drawings
In order to make the purpose, technical scheme and beneficial effect of the utility model clearer, the utility model provides a following figure explains:
fig. 1 is a circuit diagram of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
As shown in fig. 1, the utility model discloses a motor back electromotive force switch protection circuit, protection circuit contains MOS pipe Q1, triode Q2 and amplifier U1.
The drain electrode of MOS pipe Q1 is connected to first power input end, the source electrode of MOS pipe Q1 is as the first output end of protection circuit, the source electrode of MOS pipe Q1 is still connected to the collecting electrode of triode Q2 through the series connection of resistance R1 and resistance R3, the emitter of triode Q2 is connected to second power input end, the drain electrode of MOS pipe Q1 is still connected to the negative pole of diode D2 through resistance R2, the positive pole of diode D2 is connected to the second power input end.
The output end of the amplifier U1 is connected with the base of the triode Q2 through a resistor R6, the non-inverting input end of the amplifier U1 is connected with the cathode of a diode D2 through a resistor R4, the non-inverting input end of the amplifier U1 is also connected with the cathode of a diode D3, and the anode of the diode D3 is connected with a second power supply input end.
The inverting input of the amplifier U1 is connected to the first output of the protection circuit through a resistor R5, and the inverting input of the amplifier U1 is also connected to the second output of the protection circuit through a resistor R7.
In this embodiment, the first power input terminal may be an anode of a power input, the second power input terminal may be a cathode or a ground terminal of the power input, and the first output terminal and the second output terminal of the corresponding protection circuit are respectively an anode and a cathode of an output or an anode or a ground terminal of an output, as shown in fig. 1, the second power input terminal may be directly connected to the second output terminal, so as to form a protection path.
Optionally, the protection circuit further includes a diode D1, a cathode of the diode D1 is connected to a source of the MOS transistor Q1, and the diode D1, the diode D2, and the diode D3 are all voltage regulator diodes. The protection circuit further comprises a capacitor C, one end of the capacitor C is connected to the cathode of the diode D2, and the other end of the capacitor C is connected to the second power input end. A power supply terminal VCC of the amplifier U1 is connected to the cathode of the diode D2, a ground terminal GND of the amplifier U1 is connected to the second power supply input terminal, and the MOS transistor Q1 is a P-channel MOS transistor.
Introduction of the working principle:
as shown in fig. 1, for the external back electromotive force switch protection circuit of the present invention, this protection circuit can be connected in series between the motor power supply and the motor, i.e. the Input end in fig. 1 is connected to the motor power supply, and the Output end is connected to the motor. When the Output voltage of the power supply of the motor is greater than the voltage value of the motor, a parasitic diode inside the P-channel MOS tube Q1 is conducted in the forward direction, and the motor at the Output end is driven to work. At the moment, the power supply voltage at the motor is collected by the R5 and the R7. D3 is a voltage regulator tube, through connecting in series with R4, choose the appropriate steady voltage value of D3, can produce the voltage signal that the fixed benchmark threshold level and motor sampled and carry on the comparison, when the motor voltage sampling signal is lower than the benchmark threshold level (namely the motor does not produce the back electromotive force), the operational amplifier U1 outputs the high level, drive the triode Q2 to turn on, the partial pressure of R1, R3 at this moment acts on, produce the drive level of P channel MOS pipe Q1, drive Q1 to turn on, the voltage regulator tube D1 plays the role in protecting the grid source voltage of Q1 not to exceed its rated maximum value.
The utility model discloses a reverse electromotive force switch protection circuit of motor is through taking a sample to motor supply voltage to use operational amplifier to take a sample voltage and predetermine threshold voltage and carry out logic comparison, when sample voltage less than or equal to power supply output voltage, protection circuit is out of work, switching power supply supplies power for the motor, when sample voltage is higher than predetermineeing threshold voltage, operational amplifier output control signal, the switch MOS pipe of turn-off, the power supply line between switch power output and the motor cuts off, play the effect of protection power supply switching power supply.
Compared with the traditional motor reverse electromotive force protection circuit, the switch protection circuit can be externally arranged independently, the motor power supply is not required to be integrated, the flexibility during selection of the motor power supply is greatly increased, and the switch power supply with proper output voltage and power can be used as the motor power supply after the reverse electromotive force external switch protection circuit is added.
Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.
Claims (6)
1. Motor back electromotive force switch protection circuit, its characterized in that: the protection circuit comprises a MOS transistor Q1, a triode Q2 and an amplifier U1;
the drain of the MOS transistor Q1 is connected to a first power input terminal, the source of the MOS transistor Q1 serves as a first output terminal of the protection circuit, the source of the MOS transistor Q1 is further connected to the collector of the transistor Q2 through the series connection of a resistor R1 and a resistor R3, the emitter of the transistor Q2 is connected to a second power input terminal, the drain of the MOS transistor Q1 is further connected to the cathode of a diode D2 through a resistor R2, and the anode of the diode D2 is connected to the second power input terminal;
the output end of the amplifier U1 is connected with the base of the triode Q2 through a resistor R6, the non-inverting input end of the amplifier U1 is connected with the cathode of a diode D2 through a resistor R4, the non-inverting input end of the amplifier U1 is also connected with the cathode of a diode D3, and the anode of the diode D3 is connected with a second power supply input end;
the inverting input of the amplifier U1 is connected to the first output of the protection circuit through a resistor R5, and the inverting input of the amplifier U1 is also connected to the second output of the protection circuit through a resistor R7.
2. The motor back emf switch protection circuit of claim 1, wherein: the protection circuit also comprises a diode D1, and the cathode of the diode D1 is connected to the source of the MOS transistor Q1.
3. The protection circuit of claim 2, wherein: the diode D1, the diode D2 and the diode D3 are all voltage-stabilizing diodes.
4. The protection circuit of claim 1, wherein: the protection circuit further comprises a capacitor C, one end of the capacitor C is connected to the cathode of the diode D2, and the other end of the capacitor C is connected to the second power input end.
5. The protection circuit of claim 1, wherein: a power supply terminal of the amplifier U1 is connected to the cathode of the diode D2, and a ground terminal of the amplifier U1 is connected to the second power supply input terminal.
6. The protection circuit of claim 1, wherein: the MOS transistor Q1 is a P-channel MOS transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921054031.XU CN209823402U (en) | 2019-07-08 | 2019-07-08 | Motor reverse electromotive force switch protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921054031.XU CN209823402U (en) | 2019-07-08 | 2019-07-08 | Motor reverse electromotive force switch protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209823402U true CN209823402U (en) | 2019-12-20 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921054031.XU Active CN209823402U (en) | 2019-07-08 | 2019-07-08 | Motor reverse electromotive force switch protection circuit |
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| Country | Link |
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| CN (1) | CN209823402U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114597882A (en) * | 2022-03-18 | 2022-06-07 | 乐歌人体工学科技股份有限公司 | Motor drive circuit for preventing reverse electromotive force |
-
2019
- 2019-07-08 CN CN201921054031.XU patent/CN209823402U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114597882A (en) * | 2022-03-18 | 2022-06-07 | 乐歌人体工学科技股份有限公司 | Motor drive circuit for preventing reverse electromotive force |
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