Reverse electromotive force bleeder circuit

Abstract

The utility model discloses a reverse electromotive force discharge circuit, and the circuit comprises a power supply module which is connected with a motor, and is used for receiving the reverse electromotive force of the motor, and converting the reverse electromotive force into a power supply voltage; and the discharge module is connected with the motor and the power supply module, and is used for receiving the power supply voltage and then starting, converting the power supply voltage into a reference voltage, and receiving the reverse electromotive force of the motor and discharging the reverse electromotive force when detecting that the reverse electromotive force is greater than or equal to the reference voltage. The power supply module converts the reverse electromotive force of the motor into the power supply voltage and supplies power to the discharge module, the discharge module works after receiving the power supply voltage and discharges the reverse electromotive force when it is determined that the reverse electromotive force is larger than or equal to the reference voltage, and therefore the discharge module does not need an additional power source to supply power, and the discharge efficiency is improved. And the back electromotive force of the motor can be discharged without accessing a battery, so that the safety of related circuits of the motor is further improved.

Description

Technical Field

[0001] This application relates to the field of discharge circuit technology, specifically to a reverse electromotive force discharge circuit. Background Technology

[0002] Currently, various devices equipped with motors typically use batteries to receive back electromotive force (EMF), thereby discharging the back EMF and protecting the motor's related circuitry. However, if the battery fails due to over-discharge, or if the battery is removed from the device, the discharge of back EMF will also fail, inevitably damaging the motor's related circuitry. Utility Model Content

[0003] Therefore, this application provides a back electromotive force (EMF) discharge circuit, which can discharge the back EMF of the motor without the need for a battery connection, thereby further improving the safety of the motor's related circuits. The technical solution of this application is as follows:

[0004] The first aspect of this application provides a reverse electromotive force (EMF) discharge circuit, comprising: a power supply module connected to a motor, for receiving the reverse EMF of the motor and converting the reverse EMF into a power supply voltage; and a discharge module connected to the motor and the power supply module, for receiving the power supply voltage and activating it, converting the power supply voltage into a reference voltage, and receiving and discharging the reverse EMF of the motor when the reverse EMF is detected to be greater than or equal to the reference voltage.

[0005] In one embodiment of this application, the power supply module includes: a soft-start unit connected to the motor, configured to receive the back electromotive force, control the back electromotive force to rise at a preset slope, and limit the back electromotive force to a preset amplitude, and output a soft-start voltage; a voltage regulator unit connected to the soft-start unit, configured to receive the soft-start voltage and convert the soft-start voltage into the power supply voltage; and a current limiting unit connected to the voltage regulator unit and the discharge module, configured to perform current limiting processing on the power supply voltage.

[0006] In one embodiment of this application, the soft-start unit includes: a first resistor, a second resistor, a third resistor, a first capacitor, and a switching transistor; a first end of the first resistor is connected to the motor, and a second end of the first resistor is connected to the first end of the switching transistor; a first end of the second resistor is connected to the first end of the switching transistor, and a second end of the second resistor is connected to the control terminal of the switching transistor and grounded through the third resistor; the first capacitor is connected in parallel with the second resistor, and the second end of the switching transistor is connected to the voltage regulator unit.

[0007] In one embodiment of this application, the voltage regulator unit includes: a fourth resistor, a second capacitor, and a voltage regulator chip; the first end of the fourth resistor is connected to the soft-start unit, the second end of the fourth resistor is connected to the input terminal of the voltage regulator chip, and is grounded through the second capacitor; the ground terminal of the voltage regulator chip is used for grounding, and the output terminal of the voltage regulator chip is connected to the current limiting unit.

[0008] In one embodiment of this application, the current limiting unit includes: a third capacitor, a fourth capacitor, a fifth capacitor, and a fifth resistor; the first end of the fifth resistor is connected to the voltage regulating unit, and the second end of the fifth resistor is connected to the discharge module; the first end of the third capacitor is connected to the first end of the fifth resistor, and the second end of the third capacitor is grounded; the fourth capacitor is connected in parallel with the third capacitor; the first end of the fifth capacitor is connected to the second end of the fifth resistor, and the second end of the fifth capacitor is grounded.

[0009] In one embodiment of this application, the discharge module includes: a filtering unit connected to the motor, used to receive the back electromotive force and perform filtering processing; a voltage divider unit connected to the power supply module, used to divide the power supply voltage to obtain the reference voltage; a comparison unit connected to the filtering unit and the voltage divider unit, used to output a discharge signal when the filtered back electromotive force is greater than or equal to the reference voltage; and a discharge unit connected to the comparison unit and the motor, used to receive the back electromotive force of the motor and discharge it when the discharge signal is received.

[0010] In one embodiment of this application, the filtering unit includes: a sixth resistor, a seventh resistor, and a sixth capacitor; the first end of the sixth resistor is connected to the positive terminal of the motor, the second end of the sixth resistor is connected to the first input terminal of the comparison unit, and is grounded through the seventh resistor; the sixth capacitor is connected in parallel with the seventh resistor.

[0011] In one embodiment of this application, the voltage divider unit includes: an eighth resistor, a ninth resistor, and a seventh capacitor; the first end of the eighth resistor is connected to the power supply module, the second end of the eighth resistor is connected to the second input terminal of the comparator unit, and is grounded through the ninth resistor; the seventh capacitor is connected in parallel with the ninth resistor.

[0012] In one embodiment of this application, the comparison unit includes: an operational amplifier, a tenth resistor, an eleventh resistor, and an eighth capacitor; the positive input terminal of the operational amplifier is connected to the filtering unit, the negative input terminal of the operational amplifier is connected to the voltage divider unit, the power supply terminal of the operational amplifier is connected to the power supply module, and the output terminal of the operational amplifier is connected to the bleeder unit through the tenth resistor; the first terminal of the eleventh resistor is connected between the tenth resistor and the bleeder unit, and the second terminal of the eleventh resistor is grounded; the eighth capacitor is connected in parallel with the eleventh resistor.

[0013] In one embodiment of this application, the discharge unit includes: a discharge resistor and a switching chip; the control terminal of the switching chip is connected to the comparison unit, the first terminal of the switching chip is connected to the positive terminal of the motor through the discharge resistor, and the second terminal of the switching chip is grounded.

[0014] This application embodiment converts the motor's back electromotive force into a supply voltage by setting a power supply module to power the discharge module. After receiving the supply voltage, the discharge module operates and discharges the back electromotive force when it determines that the back electromotive force is greater than or equal to the reference voltage. This allows the discharge module to discharge the motor's back electromotive force without the need for an external power supply and without the need for a battery connection, thereby further improving the safety of the motor's related circuits. Attached Figure Description

[0015] Figure 1 This is a schematic block diagram of a reverse electromotive force discharge circuit provided in an embodiment of this application.

[0016] Figure 2 This is a schematic block diagram of a power supply module provided in an embodiment of this application.

[0017] Figure 3 This is a circuit diagram of a power supply module provided in an embodiment of this application.

[0018] Figure 4 This is a schematic block diagram of a discharge module provided in an embodiment of this application.

[0019] Figure 5 This is a circuit diagram of a discharge module provided in an embodiment of this application.

[0020] Figure 6 This is a schematic block diagram of a lawnmower provided in an embodiment of this application. Detailed Implementation

[0021] It should be noted that in the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence.

[0022] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0023] Please refer to Figure 1 , Figure 1 This is a schematic block diagram of a reverse electromotive force (EMF) discharge circuit provided in an embodiment of this application. The reverse EMF discharge circuit 100 includes a power supply module 110 and a discharge module 120.

[0024] In this embodiment, the power supply module 110 is connected to the motor 101 and is used to receive the reverse electromotive force of the motor 101 and convert the reverse electromotive force into a power supply voltage.

[0025] The aforementioned motor 101 includes various electric motors with electromagnetic coils. When the motor 101 rotates under the action of force without being electrically driven, it generates the aforementioned back electromotive force (EMF). To prevent the back EMF from affecting other circuits in the device equipped with the motor 101, it is necessary to release the back EMF in a timely manner. For example, in an electric lawnmower equipped with motor 101, when the lawnmower is not started, if the user pushes the lawnmower, causing the motor 101 to rotate under the thrust, the motor 101 will generate a back EMF. In addition, the back EMF release circuit 100 of this application can also be applied to intelligent robot devices equipped with motor 101, such as sweeping robots, snow removal robots, and swimming pool robots, without limitation.

[0026] In some embodiments, the power supply module 110 can be connected to the positive terminal of the motor 101. When the motor 101 is subjected to force and rotates to generate a reverse electromotive force, the positive terminal of the motor 101 can generate a voltage. The power supply module 110 receives the voltage and converts it into the power supply voltage described above.

[0027] The discharge module 120 is connected to the motor 101 and the power supply module 110. The discharge module 120 is used to start after receiving the power supply voltage, convert the power supply voltage into a reference voltage, and receive the back electromotive force of the motor 101 and discharge it when the back electromotive force is detected to be greater than or equal to the reference voltage.

[0028] It is understood that in this embodiment of the application, the power supply module 110 is set to convert the reverse electromotive force of the motor 101 into a power supply voltage to power the discharge module 120. After receiving the power supply voltage, the discharge module 120 operates and discharges the reverse electromotive force when it is determined that the reverse electromotive force is greater than or equal to the reference voltage. This allows the discharge module 120 to discharge the reverse electromotive force of the motor 101 without the need for an additional power supply and without the need for a battery connection, thereby further improving the safety of the related circuits of the motor 101.

[0029] Please refer to Figure 2 , Figure 2 This is a schematic block diagram of a power supply module 110 provided in an embodiment of this application. The power supply module 110 includes a soft start unit 111, a voltage stabilizing unit 112, and a current limiting unit 113.

[0030] In this embodiment, the soft-start unit 111 is connected to the motor 101 and is used to receive the back electromotive force, control the back electromotive force to rise according to a preset slope, limit the back electromotive force to a preset amplitude, and output a soft-start voltage.

[0031] The voltage regulator unit 112 is connected to the soft-start unit 111 and is used to receive the soft-start voltage and convert the soft-start voltage into the power supply voltage.

[0032] The current limiting unit 113 is connected to the voltage regulating unit 112 and the discharge module 120, and is used to limit the current of the power supply voltage.

[0033] It is understood that, in this embodiment of the application, by setting a soft-start unit 111 to control the back electromotive force to rise at a preset slope and limit it to a preset amplitude, damage to the subsequent voltage regulator unit 112 caused by excessively high back electromotive force can be effectively avoided. In some embodiments, the soft-start unit 111 can control the voltage in the back electromotive force to rise at a preset slope and limit the maximum current of the back electromotive force to a preset amplitude.

[0034] Please refer to Figure 3 , Figure 3 This is a circuit diagram of a power supply module 110 provided in an embodiment of this application. The power supply module 110 includes: a soft-start unit 111, a voltage regulator unit 112, and a current limiting unit 113.

[0035] In this embodiment, the soft-start unit 111 includes: a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1, and a switching transistor Q1. The first end of the first resistor R1 is connected to the motor 101, and the second end of the first resistor R1 is connected to the first end of the switching transistor Q1. The first end of the second resistor R2 is connected to the first end of the switching transistor Q1, and the second end of the second resistor R2 is connected to the control terminal of the switching transistor Q1 and grounded through the third resistor R3. The first capacitor C1 is connected in parallel with the second resistor R2, and the second end of the switching transistor Q1 is connected to the voltage regulator unit 112.

[0036] It is understood that the soft start unit 111 receives the reverse electromotive force of the motor 101 through the first resistor R1, and charges the first capacitor C1 after being divided by the second resistor R2 and the third resistor R3, thereby achieving a delayed power-on effect. After the voltage of the first capacitor C1 reaches the conduction voltage of the switch Q1, the switch Q1 conducts its first and second terminals. The voltage of the second terminal of the switch Q1 gradually rises and eventually matches the voltage of the first terminal, thereby preventing the voltage of the instantaneous jump of the reverse electromotive force from being directly transmitted to the voltage regulator unit 112.

[0037] Among them, the aforementioned switch Q1 can be a P-MOS type switch Q1, with the first terminal being the source, the second terminal being the drain, and the control terminal being the gate.

[0038] The voltage regulator unit 112 includes a fourth resistor R4, a second capacitor C2, and a voltage regulator chip U1. The first end of the fourth resistor R4 is connected to the soft-start unit 111, and the second end of the fourth resistor R4 is connected to the input terminal of the voltage regulator chip U1 and grounded through the second capacitor C2. The ground terminal of the voltage regulator chip U1 is used for grounding, and the output terminal of the voltage regulator chip U1 is connected to the current limiting unit.

[0039] The current limiting unit includes: a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a fifth resistor R5. The first terminal of the fifth resistor R5 is connected to the voltage regulator unit 112, and the second terminal of the fifth resistor R5 is connected to the discharge module 120. The first terminal of the third capacitor C3 is connected to the first terminal of the fifth resistor R5, and the second terminal of the third capacitor C3 is grounded. The fourth capacitor C4 is connected in parallel with the third capacitor C3. The first terminal of the fifth capacitor C5 is connected to the second terminal of the fifth resistor R5, and the second terminal of the fifth capacitor C5 is grounded.

[0040] Please refer to Figure 4 , Figure 4 This is a schematic block diagram of a discharge module 120 provided in an embodiment of this application. The discharge module 120 includes: a filtering unit 121, a voltage divider unit 122, a comparison unit 123, and a discharge unit 124.

[0041] In this embodiment, the filter unit 121 is connected to the motor 101 and is used to receive the back electromotive force and perform filtering.

[0042] The voltage divider unit 122 is connected to the power supply module 110 and is used to divide the power supply voltage to obtain a reference voltage.

[0043] The comparison unit 123 is connected to the filter unit 121 and the voltage divider unit 122, and is used to output a discharge signal when the back electromotive force after filtering is greater than or equal to the reference voltage.

[0044] The discharge unit 124 is connected to the comparison unit 123 and the motor 101, and is used to receive the reverse electromotive force of the motor 101 and discharge it when a discharge signal is received.

[0045] It is understood that in this embodiment, the discharge circuit uses a voltage divider unit 122 to divide the supply voltage to obtain a reference voltage, thus eliminating the need for an external power supply to generate the reference voltage. The power supply terminal of the comparison unit 123 is also connected to the power supply module 110 to receive the supply voltage and operate accordingly. When it determines that the back electromotive force is greater than or equal to the reference voltage, i.e., when the current back electromotive force is too large and may damage the relevant control circuitry of the motor 101, a discharge signal is generated to control the discharge unit 124 to receive the back electromotive force and discharge it.

[0046] Please refer to Figure 5 , Figure 5 This is a circuit diagram of a discharge module 120 provided in an embodiment of this application. The discharge module 120 includes: a filtering unit 121, a voltage divider unit 122, a comparison unit 123, and a discharge unit 124.

[0047] In this embodiment, the filter unit 121 includes a sixth resistor R6, a seventh resistor R7, and a sixth capacitor C6. The first end of the sixth resistor R6 is connected to the positive terminal of the motor 101, and the second end of the sixth resistor R6 is connected to the first input terminal of the comparator unit 123 and grounded through the seventh resistor R7. The sixth capacitor C6 is connected in parallel with the seventh resistor R7.

[0048] Voltage divider unit 122 includes an eighth resistor R8, a ninth resistor R9, and a seventh capacitor C7. The first end of the eighth resistor R8 is connected to the power supply module 110, and the second end of the eighth resistor R8 is connected to the second input terminal of the comparator unit 123, and grounded through the ninth resistor R9. The seventh capacitor C7 is connected in parallel with the ninth resistor R9.

[0049] The comparator unit 123 includes: an operational amplifier K1, a tenth resistor R10, an eleventh resistor R11, and an eighth capacitor C8. The positive input terminal of operational amplifier K1 is connected to the filter unit 121, the negative input terminal of operational amplifier K1 is connected to the voltage divider unit 122, the power supply terminal of operational amplifier K1 is connected to the power supply module 110, and the output terminal of operational amplifier K1 is connected to the bleeder unit 124 through the tenth resistor R10. The first terminal of the eleventh resistor R11 is connected between the tenth resistor R10 and the bleeder unit 124, and the second terminal of the eleventh resistor R11 is grounded. The eighth capacitor C8 is connected in parallel with the eleventh resistor R11.

[0050] For example, if the standard supply voltage of the operational amplifier K1 is 5V, then the supply voltage provided by the soft-start unit 111 is also 5V. After being stepped down by the voltage divider unit 122, a reference voltage of 3.3V is obtained and input to the negative input terminal of the operational amplifier K1. When the reverse electromotive force at the positive input terminal of the operational amplifier K1 is greater than 3.3V, the operational amplifier K1 outputs a discharge signal. In some embodiments, the discharge signal includes a high-level signal.

[0051] The bleedering unit 124 includes a bleedering resistor R12 and a switching chip U2. The control terminal of the switching chip U2 is connected to the comparator unit 123. The first terminal of the switching chip U2 is connected to the positive terminal of the motor 101 through the bleedering resistor R12, and the second terminal of the switching chip U2 is grounded. When the bleedering signal is high, the switching chip U2 can be an N-MOS (Negative-channel Metal-Oxide-Semiconductor) switching chip U2, with the first terminal being the drain, the second terminal being the source, and the control terminal being the gate. When the bleedering signal is low, the switching chip U2 can be a P-MOS (positive-channel Metal-Oxide-Semiconductor) switching chip U2, with the first terminal being the source, the second terminal being the drain, and the control terminal being the gate.

[0052] In some embodiments, the aforementioned discharge resistor R12 can also be replaced by various devices that rapidly absorb and discharge energy, such as high-power LEDs (LEDs, light-emitting diodes) and high-power fuses, etc., without limitation.

[0053] Please refer to Figure 6 , Figure 6This is a schematic block diagram of a lawnmower provided in an embodiment of this application. The lawnmower 10 includes a motor 101 and a back electromotive force discharge circuit 100 of any of the above embodiments. It is understood that the beneficial effects achieved by the lawnmower in this embodiment can be referred to the beneficial effects of the back electromotive force discharge circuit 100 in the foregoing embodiments, and will not be repeated here.

[0054] The above embodiments are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.

Claims

1. A reverse electromotive force discharge circuit, characterized in that, include: A power supply module, connected to the motor, is used to receive the back electromotive force of the motor and convert the back electromotive force into a power supply voltage; The discharge module is connected to the motor and the power supply module. It is used to start after receiving the power supply voltage, convert the power supply voltage into a reference voltage, and receive the back electromotive force of the motor and discharge it when the back electromotive force is detected to be greater than or equal to the reference voltage.

2. The reverse electromotive force discharge circuit as described in claim 1, characterized in that, The power supply module includes: A soft-start unit, connected to the motor, is used to receive the back electromotive force, control the back electromotive force to rise at a preset slope, limit the back electromotive force to a preset amplitude, and output a soft-start voltage. A voltage regulator unit, connected to the soft-start unit, is used to receive the soft-start voltage and convert the soft-start voltage into the supply voltage; The current limiting unit is connected to the voltage regulating unit and the discharge module, and is used to limit the current of the power supply voltage.

3. The reverse electromotive force discharge circuit as described in claim 2, characterized in that, The soft-start unit includes: a first resistor, a second resistor, a third resistor, a first capacitor, and a switching transistor; The first end of the first resistor is connected to the motor, and the second end of the first resistor is connected to the first end of the switching transistor; the first end of the second resistor is connected to the first end of the switching transistor, and the second end of the second resistor is connected to the control terminal of the switching transistor and grounded through the third resistor; the first capacitor is connected in parallel with the second resistor, and the second end of the switching transistor is connected to the voltage regulator unit.

4. The reverse electromotive force discharge circuit as described in claim 2, characterized in that, The voltage regulator unit includes: a fourth resistor, a second capacitor, and a voltage regulator chip; The first end of the fourth resistor is connected to the soft-start unit, the second end of the fourth resistor is connected to the input terminal of the voltage regulator chip, and is grounded through the second capacitor; the ground terminal of the voltage regulator chip is used for grounding, and the output terminal of the voltage regulator chip is connected to the current limiting unit.

5. The reverse electromotive force discharge circuit as described in claim 2, characterized in that, The current limiting unit includes: a third capacitor, a fourth capacitor, a fifth capacitor, and a fifth resistor; The first end of the fifth resistor is connected to the voltage regulator unit, and the second end of the fifth resistor is connected to the discharge module; the first end of the third capacitor is connected to the first end of the fifth resistor, and the second end of the third capacitor is grounded; the fourth capacitor is connected in parallel with the third capacitor; the first end of the fifth capacitor is connected to the second end of the fifth resistor, and the second end of the fifth capacitor is grounded.

6. The reverse electromotive force discharge circuit as described in claim 1, characterized in that, The discharge module includes: A filtering unit, connected to the motor, is used to receive the back electromotive force and perform filtering processing; A voltage divider unit, connected to the power supply module, is used to divide the power supply voltage to obtain the reference voltage. A comparison unit, connected to the filtering unit and the voltage divider unit, is used to output a discharge signal when the filtered reverse electromotive force is greater than or equal to the reference voltage. The discharge unit, connected to the comparison unit and the motor, is used to receive the reverse electromotive force of the motor and discharge it when the discharge signal is received.

7. The reverse electromotive force discharge circuit as described in claim 6, characterized in that, The filtering unit includes: a sixth resistor, a seventh resistor, and a sixth capacitor; The first end of the sixth resistor is connected to the positive terminal of the motor, the second end of the sixth resistor is connected to the first input terminal of the comparator unit, and is grounded through the seventh resistor; the sixth capacitor is connected in parallel with the seventh resistor.

8. The reverse electromotive force discharge circuit as described in claim 6, characterized in that, The voltage divider unit includes: an eighth resistor, a ninth resistor, and a seventh capacitor; The first end of the eighth resistor is connected to the power supply module, the second end of the eighth resistor is connected to the second input terminal of the comparator unit, and is grounded through the ninth resistor; the seventh capacitor is connected in parallel with the ninth resistor.

9. The reverse electromotive force discharge circuit as described in claim 7, characterized in that, The comparison unit includes: an operational amplifier, a tenth resistor, an eleventh resistor, and an eighth capacitor; The positive input terminal of the operational amplifier is connected to the filter unit, the negative input terminal of the operational amplifier is connected to the voltage divider unit, the power supply terminal of the operational amplifier is connected to the power supply module, and the output terminal of the operational amplifier is connected to the bleeder unit through the tenth resistor; the first terminal of the eleventh resistor is connected between the tenth resistor and the bleeder unit, and the second terminal of the eleventh resistor is grounded; the eighth capacitor is connected in parallel with the eleventh resistor.

10. The reverse electromotive force discharge circuit as described in claim 7, characterized in that, The discharge unit includes: a discharge resistor and a switching chip; The control terminal of the switching chip is connected to the comparator unit, the first terminal of the switching chip is connected to the positive terminal of the motor through the bleeder resistor, and the second terminal of the switching chip is grounded.

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