Contactless range hood control circuit

Abstract

The utility model relates to the technical field of range hood control, and discloses a stable contactless range hood control circuit with higher reliability, which comprises a first bistable circuit (101) for receiving a first level signal, a speed switching circuit (104) and a second bistable circuit (102) for receiving a second level signal, when the input first level signal and the second level signal are both low levels, the first bistable circuit (101) and the second bistable circuit (102) are turned over, the output is both low levels, and the low levels are used for triggering the speed switching circuit (104) to control the motor to operate at a high speed or a low speed.

Description

Technical Field

[0001] The utility model relates to the technical field of range hood control, and more specifically to a contactless range hood control circuit. Background Art

[0002] Range hoods are commonly used household appliances in daily life. They can discharge the fumes, exhaust gases and other harmful gases generated in the kitchen / indoors to the outside during cooking. At present, the existing range hoods are mainly composed of a housing, a fan, a filter and an oil collection device. In order to cope with the size of fumes in different cooking situations, a multi-speed motor is generally used to adjust the air volume. Two relays are usually used to connect the high-speed gear line and the low-speed gear line of the multi-speed motor respectively, and the motor speed is controlled by switching the relays.

[0003] However, when the motor switches from low speed to high speed or vice versa, the relay needs to switch quickly to control the motor to start or slow down quickly. If the relay fails to operate in time, it may cause damage caused by excessive current due to the motor's inability to quickly reach the rated speed. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a contactless range hood control circuit with high reliability and stability, in view of the defect of the prior art that when the relay fails to operate in time, the motor may not be able to quickly reach the rated speed, thereby causing harm caused by excessive current.

[0005] The technical solution adopted by the utility model to solve the technical problem is to construct a contactless range hood control circuit, which has:

[0006] A first bistable circuit is configured in the control circuit, and an input end thereof is connected to one end of a capacitor module for receiving a first level signal;

[0007] a speed switching circuit, an input end of which is connected to the first output end of the first bistable circuit;

[0008] The second bistable circuit has an input end connected to one end of another capacitor module and is used to receive a second level signal.

[0009] The output terminal of the second bistable circuit is connected to the second output terminal of the first bistable circuit,

[0010] When the first level signal and the second level signal input are both low level, the first bistable circuit and the second bistable circuit flip, and the outputs are both low level, and the low level is used to trigger the speed switching circuit to control the motor to run at high or low speed.

[0011] In some embodiments, the speed switching circuit includes a second thyristor and a third thyristor.

[0012] The control end of the second thyristor is connected to the first output end of the first bistable circuit.

[0013] The control end of the third thyristor is connected to the second output end of the first bistable circuit.

[0014] In some embodiments, the first transistor, the second transistor and the third transistor are also included.

[0015] The base of the first transistor is connected to the first output terminal of the first bistable circuit.

[0016] The emitter of the first transistor is coupled to the control terminal of the second thyristor.

[0017] The base of the second transistor is connected to the second output terminal of the first bistable circuit.

[0018] The emitter of the second transistor is coupled to the control terminal of the third thyristor.

[0019] The base of the third transistor is connected to the output end of the second bistable circuit.

[0020] The emitter of the third transistor is connected to the collectors of the first transistor and the second transistor respectively.

[0021] The collector of the third transistor is connected to the common terminal,

[0022] When the bases of the first transistor and the third transistor are at a low level, the second thyristor is controlled to be turned on to control the motor to run at a low speed;

[0023] When the bases of the second transistor and the third transistor are at a low level, the transistors are controlled to be turned on, and the third thyristor is controlled to be turned on, so as to control the motor to run at a high speed.

[0024] In some implementations, the first transistor, the second transistor, and the third transistor are selected as PNP transistors.

[0025] In some embodiments, the first bistable circuit includes a first inverter and a second inverter.

[0026] The input terminal of the first inverter is connected to one end of the first capacitor,

[0027] The output terminal of the first inverter is connected to the input terminal of the second inverter and the control terminal of the second thyristor.

[0028] One end of the second capacitor is connected to the input end of the second inverter,

[0029] The output terminal of the second inverter is connected to the control terminal of the third thyristor,

[0030] The other ends of the first capacitor and the second capacitor are connected to a common end.

[0031] In some embodiments, a second touch switch is connected between the input terminals of the first inverter and the second inverter.

[0032] In some embodiments, the second bistable circuit includes a third inverter and a fourth inverter.

[0033] The input terminal of the third inverter is connected to one end of the third capacitor,

[0034] The output terminal of the third inverter is connected to the input terminal of the fourth inverter,

[0035] One end of the fourth capacitor is connected to the input end of the fourth inverter,

[0036] The other ends of the third capacitor and the fourth capacitor are connected to a common end.

[0037] In some embodiments, a third touch switch is connected between the input terminals of the third inverter and the fourth inverter.

[0038] In some embodiments, a voltage stabilizing filter circuit is also included.

[0039] The input end of the voltage stabilizing filter circuit is connected to the mains output side, and is used to receive a power signal, and perform voltage reduction and voltage stabilization processing on the power signal, and output a voltage signal.

[0040] Anodes of the second thyristor and the third thyristor are connected to the output end of the voltage stabilizing and filtering circuit for receiving the voltage signal.

[0041] In the contactless range hood control circuit described in the utility model, a first bistable circuit for receiving a first level signal, a speed switching circuit and a second bistable circuit are included, wherein the second bistable circuit is used to receive a second level signal, when the input first level signal and the second level signal are both low level, the first bistable circuit and the second bistable circuit are flipped, and the output is both low level, and the low level is used to trigger the speed switching circuit to control the motor to run at high speed or low speed. Compared with the prior art, the first bistable circuit and the second bistable circuit are used to flip the input level, that is, when the input is low level, the process is low-high-low, thereby controlling the speed switching circuit to operate, so as to control the motor to run at low speed or high speed; controlling the motor to run at high speed, or switching from high speed to low speed, or controlling it to stop running at low speed can effectively solve the problem that when the relay cannot act in time during the speed switching process of the motor, the motor may not be able to quickly reach the rated speed, causing the harm caused by excessive current, thereby affecting the service life of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0043] Figure 1 The utility model provides a circuit principle diagram of a contactless range hood control circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the specific implementation methods of the present utility model are now described in detail with reference to the accompanying drawings.

[0045] like Figure 1 As shown, in the first embodiment of the contactless range hood control circuit of the present invention, the contactless range hood control circuit 10 includes a first bistable circuit 101, a second bistable circuit 102, a third bistable circuit 103, a speed switching circuit 104 and a voltage stabilizing filter circuit 105.

[0046] Wherein, the bistable circuit (101-103) is always in the original stable state without the action of an external trigger signal; under the action of an external input trigger signal, it flips from one stable state to another stable state;

[0047] The speed switching circuit 104 is used to receive a level signal (such as a high level or a low level) input by the bistable circuit (102-103) to control the on or off state of any switch tube inside it, thereby controlling the working state of the motor M;

[0048] The voltage stabilizing and filtering circuit 105 is used to receive the power signal from the mains side (~220V), and to step down, stabilize and filter the input power signal, and output a +8.5V DC voltage signal as the working power signal of the bistable circuit (101-103) and the speed switching circuit 104.

[0049] Specifically, the first bistable circuit 101 is configured in the control circuit, and its input end is connected to one end of a capacitor module for receiving a first level signal.

[0050] When the first level signal is at a high level, the signal processing process of the first bistable circuit 101 is high-low-high;

[0051] When the first level signal is at a low level, the signal processing process of the first bistable circuit 101 is low-high-low;

[0052] The input end of the speed switching circuit 104 is connected to the first output end of the first bistable circuit 101, and is used to receive the trigger signal input by the first bistable circuit 101.

[0053] When the trigger signal output by the first bistable circuit 101 is at a high level, the speed switching circuit 104 is in a cut-off state;

[0054] When the trigger signal output by the first bistable circuit 101 is at a low level, the speed switching circuit 104 is controlled to be turned on to control the motor M to work;

[0055] Furthermore, the input end of the second bistable circuit 102 is connected to one end of another capacitor module for receiving a second level signal.

[0056] When the second level signal is at a high level, the signal processing process of the second bistable circuit 102 is high-low-high;

[0057] When the second level signal is at a low level, the signal processing process of the second bistable circuit 102 is low-high-low;

[0058] The output end of the second bistable circuit 102 is connected to the second output end of the first bistable circuit 101.

[0059] When the input first level signal and the second level signal are both at low level, the first bistable circuit 101 and the second bistable circuit 102 flip, and the outputs are both at low level, which is used to trigger the speed switching circuit 104 to control the motor M to run at high speed or low speed.

[0060] By using the present technical solution, the first bistable circuit 101 and the second bistable circuit 102 are used to flip the input level, that is, when the input is at a low level, the process is low level-high level-low level, thereby controlling the speed switching circuit 104 to control the motor to run at high or low speed, or

[0061] Control the motor to run at high speed, or

[0062] Control the motor to switch from high speed to low speed, or

[0063] Stopping the motor at a low speed can effectively solve the problem that when the relay fails to operate in time during the speed switching process, the motor may not be able to quickly reach the rated speed, causing damage caused by excessive current, thereby affecting the service life of the motor.

[0064] In some implementations, in order to ensure the reliability of the switching of the motor working state, the speed switching circuit 104 may include a second thyristor T102 and a third thyristor T103 which have a switching function.

[0065] Specifically, the control end of the second thyristor T102 is connected to the first output end (corresponding to pin 2) of the first bistable circuit 101, and is used to receive the trigger level output by the first output end of the first bistable circuit 101, so as to control the second thyristor T102 to switch on or off;

[0066] The control end of the third thyristor T103 is connected to the second output end (corresponding to pin 4) of the first bistable circuit 101 for receiving the trigger level outputted by the second output end of the first bistable circuit 101 to control the third thyristor T103 to switch on or off.

[0067] In some embodiments, in order to ensure the reliability of switching the motor working state, a first transistor VT101, a second transistor VT102 and a third transistor VT103 may be set in the control circuit, wherein the first transistor VT101, the second transistor VT102 and the third transistor VT103 are selected as PNP transistors, which have a switching function.

[0068] Specifically, the base of the first transistor VT101 is connected to the first output terminal (corresponding to pin 2) of the first bistable circuit 101 through the second resistor R102.

[0069] The emitter of the first transistor VT101 is connected to the control terminal of the second thyristor T102 through the seventh resistor R107.

[0070] The base of the second transistor VT102 is connected to the second output terminal (corresponding to pin 4) of the first bistable circuit 101 through the third resistor R103.

[0071] The emitter of the second transistor VT102 is connected to the control terminal of the third thyristor T103 through the eighth resistor R108.

[0072] The base of the third transistor VT103 is connected to the output end of the second bistable circuit 102 through the eleventh resistor R111.

[0073] The emitter of the third transistor VT103 is connected to the collectors of the first transistor VT101 and the second transistor VT102 respectively.

[0074] The collector of the third transistor VT103 is connected to the common terminal.

[0075] When the input terminals of the first bistable circuit 101 and the second bistable circuit 102 are at a high level, the first output terminal (corresponding to pin 2) of the first bistable circuit 101 and the first output terminal (corresponding to pin 6) of the second bistable circuit 102 output a low level.

[0076] When the bases of the first transistor VT101 and the third transistor VT103 are at a low level, the second thyristor T102 is controlled to be turned on to control the motor to run at a low speed;

[0077] When the input terminal (corresponding to pin 1) of the first bistable circuit 101 is at a low level, the second output terminal (corresponding to pin 4) of the first bistable circuit 101 is at a low level.

[0078] When the bases of the second transistor VT102 and the third transistor VT103 are at a low level, the second transistor VT102 and the third transistor VT103 are controlled to be turned on, and the third thyristor T103 is controlled to be turned on to control the high-speed operation of the motor.

[0079] In some embodiments, the first bistable circuit 101 includes a first inverter U1A and a second inverter U1B, wherein the inverter can invert the phase of an input signal by 180 degrees and output the signal.

[0080] Specifically, the input end (corresponding to pin 1) of the first inverter U1A is connected to one end of the first capacitor C101.

[0081] The output end (corresponding to pin 2) of the first inverter U1A is connected to the input end (corresponding to pin 3) of the second inverter U1B and the control end of the second thyristor T102.

[0082] One end of the second capacitor C102 is connected to the input end (corresponding to pin 3) of the second inverter U1B through the first resistor R101.

[0083] The output end of the second inverter U1B (corresponding to pin 4) is connected to the control end of the third thyristor T103.

[0084] The other ends of the first capacitor C101 and the second capacitor C102 are connected to the common end.

[0085] The first capacitor C101 and the second capacitor C102 input a trigger signal to the first inverter U1A and the second inverter U1B, so that the first inverter U1A and the second inverter U1B perform flipping control on the input trigger signal.

[0086] It should be noted that the first capacitor C101 and the second capacitor C102 serve as a capacitor module.

[0087] In some embodiments, a second touch switch K2 is connected between the input terminals of the first inverter U1A and the second inverter U1B.

[0088] When the input terminal (corresponding to pin 1) of the first inverter U1A is at a high level, the first output terminal (corresponding to pin 2) of the first inverter U1A outputs a low level, and when the base of the first transistor VT101 is at a low level, the second thyristor T102 is controlled to be turned on to control the motor to run at a low speed;

[0089] When the second touch switch K2 is pressed, the first capacitor C101 and the second capacitor C102 charge the input end (corresponding to pin 3) of the second inverter U1B, the output end (corresponding to pin 4) of the second inverter U1B is at a low level, the base of the first transistor VT101 is at a high level, the base of the second transistor VT102 is at a low level, the second transistor VT102 is controlled to be turned on, and the third thyristor T103 is controlled to be turned on to control the motor to switch from low speed to high speed.

[0090] In some embodiments, the second bistable circuit 102 includes a third inverter U1C and a fourth inverter U1D, wherein the inverter can invert the phase of the input signal by 180 degrees and output it.

[0091] Specifically, the input end (corresponding to pin 5) of the third inverter U1C is connected to one end of the third capacitor C103.

[0092] The output end of the third inverter U1C (corresponding to pin 6) is connected to the input end of the fourth inverter U1D (corresponding to pin 7).

[0093] One end of the fourth capacitor C104 is connected to the input end (corresponding to pin 7) of the fourth inverter U1D through the twelfth resistor R112, and the output end (corresponding to pin 8) of the fourth inverter U1D is connected to the input end (corresponding to pin 5) of the third inverter U1C.

[0094] The other ends of the third capacitor C103 and the fourth capacitor C104 are connected to the common end.

[0095] In some embodiments, a third touch switch K3 is connected between the input terminals of the third inverter U1C and the fourth inverter U1D.

[0096] In some embodiments, a voltage stabilizing filter circuit 105 is further included, wherein the input end of the voltage stabilizing filter circuit 105 is connected to the output side of the 220V power supply, and is used to receive a power supply signal, and perform voltage reduction and voltage stabilization on the power supply signal, and output a +8.5V DC voltage signal.

[0097] Anodes of the second thyristor T102 and the third thyristor T103 are connected to the output end of the voltage stabilizing and filtering circuit 105 for receiving voltage signals.

[0098] In some embodiments, a third bistable circuit 103 is further included, wherein the third bistable circuit 103 includes a fifth inverter U1E and a sixth inverter U1F.

[0099] The input end (corresponding to pin 9) of the fifth inverter U1E is connected to one end of the fifth capacitor C105.

[0100] The input end (corresponding to pin 11) of the sixth inverter U1F is connected to the output end (corresponding to pin 10) of the fifth inverter U1E and one end of the sixth capacitor C106.

[0101] A first touch switch K1 is provided between the output end (corresponding to pin 10) of the fifth inverter U1E and the input end (corresponding to pin 11) of the sixth inverter U1F.

[0102] Its working principle is:

[0103] When the control circuit is instantly connected to the mains, the mains is stepped down by the fifteenth resistor R115 and the eleventh capacitor C111, and full-wave rectified by the first diode D101 and the second diode D102, and then stabilized by the first voltage stabilizing diode Z101 and the second voltage stabilizing diode Z102, and then filtered by the eighth capacitor C108, and then outputs a DC voltage of about +8.5V;

[0104] Because the voltages across the first capacitor C101, the third capacitor C103, and the fifth capacitor C105 cannot change suddenly, the input end of the first inverter U1A (corresponding to pin 1), the input end of the third inverter U1C5 (corresponding to pin 5), and the input end of the fifth inverter U1E (corresponding to pin 9) are at a low level, and the output ends of the corresponding inverters, pins 2, 6, and 10, are at a high level, so the output ends of each bistable circuit, pins 4, 8, and 12, are at a low level, therefore, the bases of the first transistor VT101, the third transistor VT103, and the fourth transistor VT104 are at a high level, the first transistor VT101, the third transistor VT103, and the fourth transistor VT104 are cut off, then the base of the second transistor VT102 is at a low level, and the transistor VT102 is turned on;

[0105] Since the third transistor VT103 is cut off, the second transistor VT102 also has no collector current. Therefore, the thyristor T101-T103 has no trigger current and is cut off. The lighting lamp HL does not light up and the motor M does not rotate.

[0106] At this time, the second capacitor C102, the fifth capacitor C105, and the sixth capacitor C106 are charged via the first resistor R01, the fourth resistor R104, and the twelfth resistor R112, and can be charged to the power supply voltage +8.5V in about 0.1 seconds.

[0107] When the first touch switch K1 is pressed instantaneously, the charge of the sixth capacitor C106 is rapidly discharged through the first touch switch K1, and the voltage on the sixth capacitor C106 rises rapidly. Under the positive feedback of the fifth inverter U1E and the sixth inverter U1F, pin 10 is inverted to a low level, and pin 14 is inverted to a high level, the fourth transistor VT104 is turned on, the first thyristor T011 is triggered and turned on, and the indicator light LED1 and the lighting lamp HL are lit.

[0108] At this time, the remaining charge of the sixth capacitor C106 becomes a low level after being discharged by the fourth resistor R104, preparing for the next reversal;

[0109] When the first touch switch K1 is pressed again, pins 10 and 12 are reversed to the original level, the indicator light and the lighting lamp are turned off, and contactless control of the lighting lamp is realized.

[0110] The high-speed operation and low-speed operation of the motor are controlled by the second touch switch K2 and the third touch switch K3. When the third touch switch K3 is pressed instantaneously, the third transistor VT103 changes from cut-off to conduction. Due to the conduction of the third transistor VT103, the collector current of the second transistor VT102 flows, the indicator lights LED4 and LED3 are lit, the third thyristor T103 is triggered and turned on, and the motor is powered to run at a high speed, so that the motor M can start quickly, avoiding the damage caused by excessive current when the motor M cannot quickly reach the rated speed when starting at a low speed;

[0111] If it is switched to low speed, just press the second touch switch K2 again, the indicator LED2 is lit, the second thyristor T102 is triggered to conduct, and the motor switches to low speed gear;

[0112] If you want to stop the motor M, just press the third touch switch K3 again;

[0113] The above process can realize the separate control of the lighting lamp HL and the motor M.

[0114] The control circuit adopts a thyristor without mechanical contacts as a large current control switch, so the control circuit is safe, reliable and has a long service life.

[0115] The embodiments of the utility model are described above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the utility model, ordinary technicians in this field can also make many forms without departing from the scope of protection of the utility model and the claims, which all fall within the protection of the utility model.

Claims

1. A contactless range hood control circuit, characterized in that: have: A first bistable circuit is configured in the control circuit, and an input end thereof is connected to one end of a capacitor module for receiving a first level signal; a speed switching circuit, an input end of which is connected to the first output end of the first bistable circuit; The second bistable circuit has an input end connected to one end of another capacitor module and is used to receive a second level signal. The output terminal of the second bistable circuit is connected to the second output terminal of the first bistable circuit, When the first level signal and the second level signal input are both low level, the first bistable circuit and the second bistable circuit flip, and the outputs are both low level, and the low level is used to trigger the speed switching circuit to control the motor to run at high or low speed.

2. The contactless range hood control circuit according to claim 1, characterized in that: The speed switching circuit includes a second thyristor and a third thyristor, The control end of the second thyristor is connected to the first output end of the first bistable circuit. The control end of the third thyristor is connected to the second output end of the first bistable circuit.

3. The contactless range hood control circuit according to claim 2, characterized in that: It also includes a first triode, a second triode and a third triode, The base of the first transistor is connected to the first output terminal of the first bistable circuit. The emitter of the first transistor is coupled to the control terminal of the second thyristor. The base of the second transistor is connected to the second output terminal of the first bistable circuit. The emitter of the second transistor is coupled to the control terminal of the third thyristor. The base of the third transistor is connected to the output end of the second bistable circuit. The emitter of the third transistor is connected to the collectors of the first transistor and the second transistor respectively. The collector of the third transistor is connected to the common terminal, When the bases of the first transistor and the third transistor are at a low level, the second thyristor is controlled to be turned on to control the motor to run at a low speed; When the bases of the second transistor and the third transistor are at a low level, the transistors are controlled to be turned on, and the third thyristor is controlled to be turned on, so as to control the motor to run at a high speed.

4. The contactless range hood control circuit according to claim 3, characterized in that: The first transistor, the second transistor and the third transistor are selected as PNP transistors.

5. The contactless range hood control circuit according to claim 2, characterized in that: The first bistable circuit includes a first inverter and a second inverter. The input terminal of the first inverter is connected to one end of the first capacitor, The output terminal of the first inverter is connected to the input terminal of the second inverter and the control terminal of the second thyristor. One end of the second capacitor is connected to the input end of the second inverter, The output terminal of the second inverter is connected to the control terminal of the third thyristor, The other ends of the first capacitor and the second capacitor are connected to a common end.

6. The contactless range hood control circuit according to claim 5, characterized in that: A second touch switch is connected between the input terminals of the first inverter and the second inverter.

7. The contactless range hood control circuit according to claim 2, characterized in that: The second bistable circuit includes a third inverter and a fourth inverter. The input terminal of the third inverter is connected to one end of the third capacitor, The output terminal of the third inverter is connected to the input terminal of the fourth inverter, One end of the fourth capacitor is connected to the input end of the fourth inverter, The other ends of the third capacitor and the fourth capacitor are connected to a common end.

8. The contactless range hood control circuit according to claim 7, characterized in that: A third touch switch is connected between the input terminals of the third inverter and the fourth inverter.

9. The contactless range hood control circuit according to claim 3, characterized in that: It also includes voltage stabilization and filtering circuits. The input end of the voltage stabilizing filter circuit is connected to the mains output side, and is used to receive a power signal, and perform voltage reduction and voltage stabilization processing on the power signal, and output a voltage signal. Anodes of the second thyristor and the third thyristor are connected to the output end of the voltage stabilizing and filtering circuit for receiving the voltage signal.

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