CN219496545U - Detection circuit for household appliance, control system and household appliance - Google Patents
Detection circuit for household appliance, control system and household appliance Download PDFInfo
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- CN219496545U CN219496545U CN202320456945.9U CN202320456945U CN219496545U CN 219496545 U CN219496545 U CN 219496545U CN 202320456945 U CN202320456945 U CN 202320456945U CN 219496545 U CN219496545 U CN 219496545U
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Abstract
The present utility model relates to a detection circuit for a household appliance, comprising: a first input terminal to which a first input signal representing a state by turning on and off an alternating current signal of positive-negative conversion is input; a first transistor to which a first input signal at the first input is transmitted and which is non-conductive at least over a half cycle of an alternating current signal; a first resistor connected in series with the first transistor on the dc path; an output terminal led out from between the first transistor and the first resistor; at least one detection module connected to the output terminal, the detection module comprising a voltage dividing resistor capable of dividing a voltage with the first resistor when the first transistor is non-conductive and the detection module forms a path. Furthermore, the utility model relates to a control system for a household appliance and to a household appliance.
Description
Technical Field
The present utility model relates to a detection circuit for a household appliance, a control system for a household appliance and a household appliance having the detection circuit and/or the control system.
Background
Currently, the functions of a Microcontroller (MCU) of a household appliance are becoming more and more abundant. To provide a more intelligent or safer use experience for the user, it is desirable to monitor the status of various switches or sensors. Thus, the number of detection signals is increasing. But in order to input more detection signals into the microcontroller, pins need to be added to the microcontroller. This would result in the microcontroller having to be redesigned and manufactured, with a concomitant significant cost increase.
The problem to be solved is how to receive more detection signals with the existing pin implementation of the microcontroller with little increase in cost.
Disclosure of Invention
The object of the present utility model is to provide a detection circuit for a household appliance, a control system for a household appliance and a household appliance, which enable a plurality of detection signals to be provided on one signal line, i.e. one pin of a microcontroller.
A first aspect of the present utility model relates to a detection circuit for a household appliance, the detection circuit comprising:
a first input terminal to which a first input signal representing a state by turning on and off an alternating current signal of positive-negative conversion is input;
a first transistor to which a first input signal at the first input is transmitted and which is non-conductive at least over a half cycle of an alternating current signal;
a first resistor connected in series with the first transistor on the dc path;
an output terminal led out from between the first transistor and the first resistor;
at least one detection module connected to the output terminal, the detection module comprising a voltage dividing resistor capable of dividing a voltage with the first resistor when the first transistor is non-conductive and the detection module forms a path.
According to the utility model, a detection circuit for a household appliance receives a first input signal at a first input. The first input signal has two states: disconnect or otherwise have no ac signal; and switching on or the presence of an ac signal.
A first input signal on the first input terminal is transferred to a first transistor. The first transistor can be turned on or off depending on whether the first input signal is at the positive half cycle, the negative half cycle, or off of the alternating current signal, depending on the type of the first transistor. When the first transistor is turned on, an output terminal led out from between the first transistor and the first resistor on the direct current path will output a low level or a high level indicating the presence of the turned-on first input signal. In this case, it is provided that the first transistor is arranged in the detection circuit in such a way that it can be switched off or not on at least half the period of the ac signal, whether the first input signal is switched on or not. In addition, at least one detection module is connected to the output terminal, and the detection module further comprises a voltage dividing resistor which can realize voltage division with the first resistor when the first transistor is not conducted and the detection module forms a passage. Therefore, the output end can realize the voltage signal output divided by the first resistor and the divider resistor.
With such an arrangement according to the utility model, the first transistor can be switched off or not on at least half the cycle of the ac signal. And if the detection module forms a channel or is triggered during the non-conduction period of the first transistor, the voltage dividing resistor of the detection module is connected to the output end, and the output end outputs a voltage signal divided by the first resistor and the voltage dividing resistor in the detection module. The detection circuit according to the utility model can thus be used to feed back whether the detection module is switched on or off via the voltage signal at the output on one half of the ac signal, and on the other half of the ac signal the on or off state of the first input signal. This means that the on-off state of the first input signal and the triggering state of the at least one detection module can be superimposed on the output signal of the same output in a time-sharing manner, so that they can be combined into one output signal in a time-resolved manner. It is thus sufficient to provide both detection signals with one signal line or on one pin of the microcontroller without having to add pins to the microcontroller and without having to redesign and manufacture the microcontroller. Furthermore, the detection circuit according to the utility model uses only a small number of conventional and inexpensive electronic components and can be integrated in a household appliance with little increase in production costs.
According to an advantageous embodiment of the utility model, the first transistor is an NPN transistor and the first input is connected to the base of the first transistor, the collector of the first transistor is connected to the dc power supply via a first resistor, the emitter of the first transistor is grounded, and the output is connected between the collector of the first transistor and the first resistor.
Here, if the first input terminal is turned on with a first input signal based on an ac signal, the NPN transistor is turned on a positive half cycle of the ac signal, and thus an output terminal connected between the collector of the first transistor and the first resistor outputs a low level. The NPN transistor is not conductive in the negative half cycle of the ac signal, whereby a high potential occurs between the collector connected to the first transistor and the first resistor: at this time, if one of the at least one detection modules forms a path or is triggered, the voltage dividing resistor of the detection module is connected to the output end and participates in voltage division, and the output end outputs a voltage signal obtained by dividing the voltage dividing resistor in the detection module; if all the detection modules do not form a channel or are not triggered, the voltage dividing resistor of the detection module is not connected to the output end so as not to participate in voltage division, and the output end outputs high level provided by the direct current power supply. In addition, the NPN transistor is also non-conductive when the first input signal is off, whereby a high potential appears between the collector connected to the first transistor and the first resistor: at this time, if one of the at least one detection modules forms a path or is triggered, the voltage dividing resistor of the detection module is connected to the output end and participates in voltage division, and the output end outputs a voltage signal obtained by dividing the voltage dividing resistor in the detection module; if all the detection modules do not form a channel or are not triggered, the voltage dividing resistor of the detection module is not connected to the output end so as not to participate in voltage division, and the output end outputs high level provided by the direct current power supply.
According to one embodiment of the utility model, the first transistor is a PNP transistor, the first input terminal is connected to a base of the first transistor, an emitter of the first transistor is connected to a dc power supply, a collector of the first transistor is grounded via a first resistor, and the output terminal is connected between the collector of the first transistor and the first resistor. In the case that the first transistor is a PNP transistor, the structure of the detection circuit is symmetrical to the circuit structure when an NPN transistor is used, but the detection logic is opposite.
Here, if the first input terminal is turned on with a first input signal based on an ac signal, the PNP transistor is turned on a negative half cycle of the ac signal, and thus the output terminal connected between the collector of the first transistor and the first resistor outputs a high level. The PNP transistor is not conducted in the positive half cycle of the alternating current signal: at this time, if one of the at least one detection modules forms a channel or is triggered, the dc power supply provided in the detection module can connect the voltage dividing resistor in series with the first resistor and participate in voltage division, and the output end outputs the voltage signal obtained by the first resistor, so as to calculate the voltage on the voltage dividing resistor; if all the detection modules do not form a channel or are not triggered, the voltage dividing resistor of the detection module is not connected to the output end so as not to participate in voltage division, and the output end outputs low level. The PNP transistor is also non-conductive when the first input signal is off: at this time, if one of the at least one detection modules forms a channel or is triggered, the voltage dividing resistor of the direct current power supply arranged in the detection module can be connected in series with the first resistor and participate in voltage division, and the output end outputs a voltage signal obtained by dividing the first resistor, so that the voltage on the voltage dividing resistor can be calculated; if all the detection modules do not form a channel or are not triggered, the voltage dividing resistor of the detection module is not connected to the output end so as not to participate in voltage division, and the output end outputs low level.
The first transistor may also be configured as a MOSFET or JFET, not limited to the first two embodiments. The layout of the detection circuit should be adapted accordingly. For transistors, both MOSFETs and JFETs are voltage controlled devices, which reduces current consumption and power loss of the detection circuit.
According to one embodiment of the present utility model, the first input terminal is connected to a fan switch, a door opening/closing sensor, a door lock switch, a strong electric water level detection sensor, a strong electric overflow detection sensor, a strong electric water leakage detection sensor, a strong electric drainage detection sensor, a heating switch, or a refrigerating switch.
According to a preferred embodiment of the present utility model, when a plurality of detection modules are present, the resistance values of the voltage dividing resistors in the respective detection modules may be different from each other. Thus, when different voltage dividing resistors are connected to the output terminal and voltage division with the first resistor is achieved, the output voltages of the output terminals will be different from each other, and thus it is possible to reliably distinguish which detection module is triggered. By this embodiment, the number of detection signals that can be provided on one signal line, i.e. on a pin of one microcontroller, is further increased, whereby a highly integrated detection circuit is realized.
According to one embodiment of the utility model, the detection module is configured as a series circuit of a second transistor, which is controlled by a second input signal at a second input, in series with the voltage divider resistor. In this way, the detection module is configured as a series circuit of the second transistor and the voltage dividing resistor. The second transistor may be controlled to be turned on or off by a second input signal at the second input terminal. When the second transistor is connected, the detection module forms a channel or is triggered, and the voltage dividing resistor can be correspondingly connected to the output end and timely participate in voltage division. It goes without saying that the use of electronic components can continue in this way when more detection modules are present, for example a further detection module being configured as a series circuit of a third transistor controlled by a third input signal at a third input terminal in series with the voltage dividing resistor, and so on.
According to one embodiment of the utility model, the second transistor is provided for driving a component of the household appliance or for detecting a switching signal or a sensor signal that is characteristic of a switching value based on a second input signal. For this purpose, in addition to the voltage dividing resistor being connected to the input, the second transistor can be used at the same time for driving components of the household appliance. The second input signal may be a drive signal from the microcontroller, which can switch on the second transistor and drive the components of the household appliance in operation. In addition, the second transistor may be configured to be triggered to turn on or off by a sensor signal characterized by a switching value.
According to one embodiment of the utility model, the components of the household appliance relate to a door lock relay, a heating pipe relay, a thyristor drive circuit or a pump drive circuit; and/or the sensing signal is provided by a water turbidity sensor, a water hardness sensor, a weak current type water level detection sensor, a weak current type overflow detection sensor, a weak current type water leakage detection sensor or a weak current type water drainage detection sensor.
According to one embodiment of the utility model, when the second transistor of the detection module is turned on or broken down, the voltage dividing resistor and the first resistor realize voltage division, so that the voltage of the output terminal changes. In this case, the detection module can likewise form a path not only when the second transistor is switched on by the second input signal, but also when the second transistor breaks down by damage, so that the voltage divider resistor is connected to the output and takes part in the voltage division. Therefore, whether the second transistor easy to damage is in fault or not can be effectively monitored through the detection module, corresponding processing can be timely carried out, and the use risk of the household appliance is avoided.
According to one embodiment of the utility model, the voltage divider resistor is embodied as a thermistor, gas sensor, force sensor, moisture sensor, light sensor or magnetic sensor, wherein the thermistor is in particular a negative temperature coefficient thermistor or a positive temperature coefficient thermistor. The detection circuit may here comprise only these sensitive components connected to ground or to a direct current power supply. The resistance of these sensitive components may vary with certain external conditions. In case that the resistance value of the first resistor is known, it is possible to determine what kind of change of external conditions, such as temperature, composition and concentration of gas, external force, humidity, illumination or magnetic field, etc., occurs through the output voltage of the output terminal. Thus, the detection circuit according to this embodiment can detect not only the switching value but also the numerical value, and further, the detection range of the detection circuit is expanded.
According to one embodiment of the utility model, the first input is provided as a door opening and closing sensor, a door lock switch, a water level detection sensor, an overflow detection sensor, a water leakage detection sensor, a water drainage detection sensor, a heating switch, a cooling switch or a fan switch for connecting a household appliance.
According to one embodiment of the utility model, the alternating current signal is a sine wave signal, a square wave signal, a sawtooth wave signal or a triangle wave signal. Preferably, the alternating current signal is 220V alternating current commercial electric signal. In this way, a household appliance operating on ac mains can simply provide a first input signal representing a state by switching on and off an ac signal, which is switched positive and negative, to the detection signal by means of its switch or sensor.
A second aspect of the utility model relates to a control system for a household appliance, comprising the aforementioned detection circuit and a microcontroller, wherein the output of the detection circuit is connected to one pin of the microcontroller.
By means of such a control system, it is possible to provide at least two detection signals on one pin of the microcontroller without having to add pins to the microcontroller, without having to redesign and manufacture the microcontroller, and with little increase in production costs.
According to one embodiment of the utility model, the control system further comprises a line synchronization circuit connected to the other pin of the microcontroller, which line synchronization circuit is able to inform at a high-low level whether the ac signal is currently in the positive half-cycle or in the negative half-cycle, in particular in the half-cycle when the first transistor is non-conductive. The first input signal input to the detection circuit is based on the alternating current signal. The line synchronization circuit can provide a clock signal to the microcontroller, by means of which it can be determined whether the ac signal is currently in the positive half-cycle or in the negative half-cycle, in particular in the half-cycle in which the first transistor is non-conductive, and the states of the different detection signals of the first input and of the detection module can then be clearly distinguished from the time-division-superimposed output signal of the detection circuit.
According to one embodiment of the utility model, the line synchronization circuit controls the output dc voltage by inputting an ac signal to the transistor. For example, in the line synchronization circuit, an ac signal may be input via a current limiting resistor to, for example, the base of an NPN transistor, with its emitter grounded. The collector of the NPN transistor is connected to the dc power supply via a resistor on the one hand and to the output of the line synchronisation circuit on the other hand. Thus, in the positive half cycle of the ac signal, the NPN transistor is turned on and the output terminal outputs a low level. In the negative half cycle of the alternating current signal, the NPN transistor is cut off, and the output end outputs high level. Thus, the line synchronization circuit can convert the alternating current signal into a square wave signal with a duty cycle of 50%.
A third aspect of the utility model relates to a household appliance comprising a washing machine, dryer, dishwasher, oven, steam box, microwave oven, refrigerator, air conditioner or food processor, with the aforementioned detection circuit and/or the aforementioned control system.
It should be noted that features, functions, effects, advantages and the like according to one aspect of the present utility model can be referred to the above description of other aspects of the present utility model as well. Furthermore, the various aspects described in the present utility model may be combined with each other in various ways.
Drawings
Fig. 1 shows a schematic circuit diagram of a detection circuit according to an embodiment of the utility model, in which an NPN transistor is used as a first transistor;
fig. 2 shows a circuit schematic of a detection circuit according to another embodiment of the present utility model, in which a PNP transistor is used as a first transistor;
fig. 3 shows a circuit diagram of a detection circuit according to a first embodiment of the utility model;
fig. 4 shows a circuit diagram of a detection circuit according to a second embodiment of the utility model;
fig. 5 shows a circuit diagram of a detection circuit according to a third embodiment of the utility model;
FIG. 6 shows a circuit diagram of an exemplary line synchronization circuit;
fig. 7 shows a block diagram of a control system according to the utility model.
Detailed Description
Fig. 1 shows a schematic circuit diagram of a detection circuit according to an embodiment of the utility model. The detection circuit for a household appliance as shown in fig. 1 comprises at least:
a first input terminal V in A first input signal representing a state by switching on and off an alternating current signal of positive-negative conversion is input to the first input terminal;
first transistor Q 1 The first input terminal V in The first input signal is transmitted to the first transistor Q 1 And the first transistor Q 1 Non-conductive at least over half a cycle of the ac signal;
on the direct current path with the first transistor Q 1 First resistor R connected in series 3 ；
One slave first transistor Q 1 And a first resistor R 3 Output terminal V led out from the middle out ；
Connected to the output terminal V out At least one detection module DM1 … DMn respectively included in the first transistor Q 1 Non-conduction and detection module DM1 … DMn can form a passage with first resistor R 3 Voltage dividing resistor R for realizing voltage division Q2 …R Qn 。
As shown, the detection circuit can be roughly divided into three parts: a first input part 1 comprising a first input and a first transistor, a second input part 2 comprising detection modules and an output part 3.
In particular, fig. 1 shows a circuit configuration using an NPN transistor as the first transistor. The first input V here in Connected to the first transistor Q 1 The base of the first transistor Q 1 Via a first resistor R 3 Connected to a DC power supply VCC, the first transistor Q 1 Is grounded and the output terminal V out Connected to the first transistor Q 1 Collector of (a) and a first resistor R 3 Between them.
In addition, fig. 1 also shows a current limiting resistor R 1 And bias resistor R 2 。
In this case, if the first input V in When the first input signal based on the alternating current signal is turned on, the NPN transistor is turned on at the positive half cycle of the alternating current signal, and is connected to the first transistor Q 1 Collector of (a) and a first resistor R 3 Output terminal V between out A low level is output. While the NPN transistor is non-conductive in the negative half cycle of the AC signal, thereby being connected to the first transistor Q 1 Collector of (a) and a first resistor R 3 A high potential appears in between: at this time, if one of the at least one detection modules DM1 … DMn forms a path or is triggered, the corresponding voltage dividing resistor of that detection module is connected to the output V out And participate in voltage division, output terminal V out Dividing the voltage signals obtained by the corresponding dividing resistors output in the detection module; if all the detection modules DM1 … DMn do not form a path or are not triggered, the voltage dividing resistor of the detection module is not connected to the output terminal V out Thus not taking part in voltage division, output terminal V out The high voltage supplied by the dc power supply VCC will be output. The NPN transistor is not turned on when the first input signal is turned off, and is connected to the first transistor Q 1 Collector of (a) and a first resistor R 3 A high potential appears in between: at this time, if the at least one detection moduleOne detection module in DM1 … DMn forms a path or is triggered, and the corresponding voltage dividing resistor of the detection module is connected to the output terminal V out And participate in voltage division, output terminal V out Dividing the voltage signals obtained by the corresponding voltage dividing resistors output in the detection module; if all the detection modules do not form a path or are not triggered, the corresponding voltage dividing resistors of the detection modules are not connected to the output terminal V out And thus does not participate in the voltage division, the output will output a high level provided by the dc supply VCC.
It can be seen that due to the first transistor Q 1 Can be turned off or not at least for half the cycle of the ac signal, and thus in the first transistor Q 1 During the non-conduction period, if the detection module forms a passage or is triggered, the voltage dividing resistor of the detection module is connected to the output end V out Output terminal V out The voltage signal divided by the voltage dividing resistor in the first resistor and the detection module is output. The detection circuit shown in fig. 1 can thus be used to feed back whether the detection module is switched on or off via the voltage signal at the output over one half of the ac signal, and the on or off state of the first input signal over the other half of the ac signal. This means that the on-off state of the first input signal and the triggering state of the at least one detection module can be superimposed on the output signal of the same output in a time-sharing manner, so that they can be combined into one output signal in a time-resolved manner. It is thus sufficient to provide both detection signals with one signal line or on one pin of the microcontroller without having to add pins to the microcontroller and without having to redesign and manufacture the microcontroller. And can be integrated in a home appliance with little increase in production cost due to the use of a small number of conventional and inexpensive electronic components.
Fig. 1 also shows the case where there are a plurality of detection modules DM1 … DMn, in which case it can also preferably be provided that: the resistance values of the voltage dividing resistors in the detection modules are different. Thus, when different voltage dividing resistors are connected to the output terminal and voltage division with the first resistor is achieved, the output terminal V out Will be different from each other and in turn can reliably distinguish which detection module is triggered. By this embodiment, the number of detection signals that can be provided on one signal line, i.e. on a pin of one microcontroller, is further increased, whereby a highly integrated detection circuit is realized.
The ac signal may be a sine wave signal, a square wave signal, a sawtooth wave signal, or a triangle wave signal. Preferably, the alternating current signal is 220V alternating current commercial electric signal.
Fig. 2 shows a schematic circuit diagram of a detection circuit according to another embodiment of the present utility model, in which a PNP transistor is used as the first transistor. At the first transistor Q 1 In the case of a PNP transistor, the structure of the detection circuit is substantially symmetrical to the circuit structure shown in fig. 1, but the detection logic is reversed.
The first input V here in Connected to the first transistor Q 1 The base of the first transistor Q 1 The emitter of the first transistor Q is connected to a DC power supply VCC 1 Via a first resistor R 3 Grounded and the output terminal V out Connected to the first transistor Q 1 Collector of (a) and a first resistor R 3 Between them. In addition, a current limiting resistor R1 and a bias resistor R2 are also shown in fig. 2.
In this case, if the first input V in When the first input signal based on the AC signal is turned on, the PNP transistor is turned on at the negative half cycle of the AC signal, thereby being connected to the first transistor Q 1 Collector of (a) and a first resistor R 3 The output terminal of the same outputs a high level. The PNP transistor is not conducted in the positive half cycle of the alternating current signal: at this time, if one of the at least one detection module forms a path or is triggered, the dc power supply provided in the detection module can make its voltage dividing resistance and the first resistance R 3 Connected in series and participate in voltage division, output terminal V out Will output a first resistor R 3 The voltage signal obtained by the upper division can be further calculated to obtain the corresponding voltage dividing resistanceA voltage on; if all the detection modules do not form a passage or are not triggered, the voltage dividing resistor of the detection module is not connected to the output end so as not to participate in voltage division, and the output end V out A low level is output. The PNP transistor is also non-conductive when the first input signal is off: at this time, if one of the at least one detection modules forms a channel or is triggered, the voltage dividing resistor of the dc power VCC provided in the detection module can be connected in series with the first resistor R3 and participate in voltage division, and the output terminal will output the voltage signal divided by the first resistor R3, so as to calculate the voltage on the voltage dividing resistor; if all the detection modules do not form a channel or are not triggered, the voltage dividing resistor of the detection module is not connected to the output end so as not to participate in voltage division, and the output end outputs low level.
Fig. 2 also shows that the detection module can be configured as a series circuit in which a second transistor is connected in series with the voltage divider resistor. Thus, the detection module is configured as a second transistor Q 2 And a second voltage-dividing resistor R Q2 Is provided. Second transistor Q 2 Can be switched on or off by a second input signal at a second input terminal connected to its base. At the second transistor Q 2 When the voltage divider is connected, the detection module forms a channel or is triggered, so that the voltage divider resistor can be correspondingly connected to the output end and timely participate in voltage division. It goes without saying that when there are more detection modules, and so on, the nth transistor Q n And the nth voltage dividing resistor R Qn And (3) connecting in series.
Fig. 3 shows a circuit diagram of a detection circuit according to a first embodiment of the utility model. Here, two detection modules are connected to the input VOUT of the detection circuit (see lower left part of fig. 3 and lower right part of fig. 3). The two detection modules can each detect the operating state of a different heating tube relay in the household appliance. The on-off signals of the different heating pipe relays are respectively input to the detection modules from the second input end VIN2 and the third input end VIN 3. In the detection module shown at the lower left, a second voltage dividing resistor R24 is connected in series with the second transistor Q2. The second transistor Q2 may be turned on or off under control of a second input signal at the second input terminal VIN 2. When the second transistor Q2 is switched on, the detection module forms a path or is triggered, and its second voltage dividing resistor R24 can be connected to the output terminal VOUT accordingly, and divided by the first resistor R18 over the non-conductive half-cycle of the first transistor Q1, in this case the negative half-cycle of the ac signal, so that the output terminal VOUT outputs a voltage signal of V7 (r24/(r18+r24)). Similarly, in the detection module shown at the lower right, the third voltage dividing resistor R25 is connected in series with the third transistor Q3, so that when the third transistor Q3 is turned on, the third voltage dividing resistor R25 divides the first resistor R18 over a half cycle in which the first transistor Q1 is non-conductive, so that the output terminal VOUT outputs a voltage signal of V7 (R25/(r18+r25)).
In this detection circuit, a fan switching signal, which characterizes the state by the switching of an ac signal, for example, can be fed to the first input VIN 1. The fan switching signal based on the ac signal turns on the first transistor Q1 at its positive half cycle, so that the output terminal outputs a low level on the positive half cycle of the ac signal to indicate the fan operation.
The above-described combination of detection signals is particularly important for a washing machine or dryer, since it is necessary to ensure that the fan must be operated when either heating pipe is switched on, otherwise the dry burning of the heating pipe would possibly cause a fire risk. By means of the detection circuit shown in fig. 3, these three detection signals can be combined in a time-sharing manner into an analog voltage signal which is output at the output VOUT and supplied to a microcontroller MCU of a household appliance, in particular a washing or drying machine. In this case, since no special distinction is required as to which heating tube relay has a signal input, the voltage dividing resistors R24 and R25 can also have the same resistance value. If both heating tube relays are on, the following voltage signal is output at output VOUT during the negative half cycle of the ac signal:
V7*(0.5*R24/(R18+0.5*R24))。
fig. 4 shows a circuit diagram of a detection circuit according to a second embodiment of the utility model. In this figure, the lower left detection module is configured as a water turbidity detection module. The second input VIN2 may be connected to a water turbidity sensor. When the water is cloudy to a certain degree, the sensing signal of the sensor triggers the second transistor Q2 to be conducted, so that the voltage dividing resistor R8 of the sensor can be connected into the output end VOUT, and is divided with the first resistor R4 during the negative half period of the alternating current signal, so that the output end VOUT outputs a voltage VCC1 (R8/(R8+R 4)).
The detection module itself in the lower right part of fig. 4 is formed as a relay drive module, such as a door lock relay drive module, a heating pipe relay drive module, or the like. Here, the third output terminal VIN3 may control the third transistor Q3 to be turned on or off, thereby driving the relay coil connected to the collector thereof to be conductive or nonconductive. When the third transistor Q3 is turned on, a voltage dividing resistor R13, which is also connected to its collector, is connected to the output terminal VOUT, and is divided by the first resistor R4 during the negative half cycle of the ac signal, so that the output terminal VOUT outputs a voltage VCC1 (R13/(r13+r4)).
The second transistor may be provided, without being limited to the above-described embodiment, as a component for driving the household appliance based on the second input signal (or the third input signal … … nth input signal) or as a sensing signal detecting a switching signal or characterized by a switching value. Illustratively, the components of the household appliance relate to a door lock relay, a heating pipe relay, a thyristor drive circuit or a pump drive circuit; and/or the sensing signal is provided by a water turbidity sensor, a water hardness sensor, a weak current type water level detection sensor, a weak current type overflow detection sensor, a weak current type water leakage detection sensor or a weak current type water drainage detection sensor.
It is also advantageous that the first input may be provided as a door opening and closing sensor, a door lock switch, a water level detection sensor, an overflow detection sensor, a water leakage detection sensor, a drain detection sensor, a heating switch, a cooling switch or a fan switch for connecting the household appliance.
Fig. 5 shows a circuit diagram of a detection circuit according to a third embodiment of the present utility model. In the detection circuit, the detection module only comprises a thermistor (such as negative temperature coefficient thermistor, positive temperature coefficient thermistor), a gas sensor, a force sensor, a humidity sensor, and a photosensitive resistorA voltage dividing resistor of a resistor or a magneto resistor. This is illustrated in fig. 5 by way of example with a negative temperature coefficient thermistor NTC. The resistance of the thermistor NTC may vary with temperature. In the half-cycle when the first transistor is non-conductive, the thermistor NTC will divide the voltage with the first resistor R4, thereby outputting VCC1 (R NTC /(R4+R NTC ) A) voltage signal. The currently sensed temperature can thus be calculated from the output voltage of the output terminal VOUT. Thus, the detection circuit according to this embodiment can detect not only the switching value but also the numerical value, and further, the detection range of the detection circuit is expanded.
Although the detection mode of the detection module is described here with a thermistor NTC having a negative temperature coefficient, other sensitive resistors may be used instead of the thermistor NTC in fig. 5, such as a gas sensor, a force sensor, a humidity sensor, a light sensor or a magneto sensor. Accordingly, and the output voltage can be used to determine the composition and concentration of the gas, external forces, humidity, illumination, or magnetic field.
Fig. 6 shows a circuit diagram of an exemplary line synchronization circuit. The line synchronization circuit may control the output dc voltage by inputting an ac signal to the transistor. For example, the input Valt of the line synchronization circuit may input an ac signal to, for example, the base of NPN transistor Q via current limiting resistors R1 and R2. The emitter of the NPN transistor Q is grounded. A bias resistor R3 is connected between the base and emitter of NPN transistor Q, and a bypass capacitor C1 and a reverse biased diode D1 are also connected between the base and ground. The collector of NPN transistor Q is connected to the dc power supply via resistor R4 on the one hand and to the output Vsyn of the line synchronization circuit via current limiting resistor R5 on the other hand. Thus, in the positive half cycle of the ac signal, NPN transistor Q is turned on, and output terminal Vsyn outputs a low level. In the negative half cycle of the ac signal, the NPN transistor Q is turned off, and the output terminal Vsyn outputs a high level. Thus, the line synchronization circuit can convert the alternating current signal into a square wave signal with a duty cycle of 50%.
The output Vsyn of the line synchronization circuit is connected to one pin of the microcontroller for informing at a high-low level whether the ac signal is currently in the positive half cycle or the negative half cycle. The line synchronisation circuit can be said to be able to supply a clock signal to the microcontroller, with which clock signal it can be determined whether the ac signal is currently in the positive half-cycle or in the negative half-cycle, in particular the half-cycle in which the first transistor should be non-conductive, and then the state of the different detection signals from the first input of the detection circuit and the detection module is clearly resolved from the output signal of the detection circuit.
Fig. 7 shows a block diagram of a control system according to the utility model. The control system shown in fig. 6 comprises a microcontroller MCU and a detection circuit DC, wherein the output of the detection circuit DC is connected to one pin of the microcontroller MCU.
The control system also comprises, particularly advantageously, a line synchronization circuit SYN connected to another pin of the microcontroller MCU, in particular as shown in fig. 6, in order to be able to inform at high and low levels whether the ac signal is currently in the positive half-cycle or in the negative half-cycle, in particular the half-cycle, in which the first transistor is not conductive.
The utility model is not limited to the embodiments shown, but includes or extends to all technical equivalents which fall within the effective scope of the appended claims. The positional references selected in the description, such as, for example, up, down, left, right, etc., refer to the direct description and the drawings shown and can be transferred to new positions in the sense of a change in position.
The features disclosed in this document can be essential for the implementation of the embodiments in different embodiments and can be implemented not only individually but also in any combination.
Although the present utility model has been described in terms of the preferred embodiments, it is not intended to be limited to the embodiments, and any person skilled in the art can make any possible variations and modifications to the technical solution of the present utility model by using the methods and technical matters disclosed above without departing from the spirit and scope of the present utility model, so any simple modifications, equivalent variations and modifications to the embodiments described above according to the technical matters of the present utility model are within the scope of the technical matters of the present utility model.
Claims (15)
1. A detection circuit for a household appliance, the detection circuit comprising:
a first input terminal to which a first input signal representing a state by turning on and off an alternating current signal of positive-negative conversion is input;
a first transistor to which a first input signal at the first input is transmitted and which is non-conductive at least over a half cycle of an alternating current signal;
a first resistor connected in series with the first transistor on the dc path;
an output terminal led out from between the first transistor and the first resistor;
at least one detection module connected to the output terminal, the detection module comprising a voltage dividing resistor capable of dividing a voltage with the first resistor when the first transistor is non-conductive and the detection module forms a path.
2. The detection circuit of claim 1, wherein the first transistor is an NPN transistor, and the first input terminal is connected to a base of the first transistor, a collector of the first transistor is connected to a dc power supply via a first resistor, an emitter of the first transistor is grounded, and the output terminal is connected between the collector of the first transistor and the first resistor.
3. The detection circuit of claim 1, wherein the first transistor is a PNP transistor, the first input is connected to a base of the first transistor, an emitter of the first transistor is connected to a dc power source, a collector of the first transistor is grounded via a first resistor, and the output is connected between the collector of the first transistor and the first resistor.
4. A detection circuit according to any one of claims 1 to 3, wherein the first input is arranged for connection to a fan switch, a door opening and closing sensor, a door lock switch, a high-current water level detection sensor, a high-current overflow detection sensor, a high-current water leakage detection sensor, a high-current water drainage detection sensor, a heating switch or a cooling switch.
5. A detection circuit according to any one of claims 1 to 3, wherein when a plurality of detection modules are present, the resistance values of the voltage dividing resistors in the respective detection modules are different.
6. A detection circuit according to any one of claims 1 to 3, wherein the detection module is configured as a series circuit of a second transistor controlled by a second input signal at the second input terminal in series with the voltage dividing resistor.
7. The detection circuit according to claim 6, wherein the second transistor is arranged for driving a component of the household appliance or for detecting a switching signal or a sensing signal characterized by a switching value based on the second input signal.
8. The detection circuit of claim 7, wherein the component of the household appliance relates to a door lock relay, a heating pipe relay, a thyristor drive circuit, or a pump drive circuit; and/or the sensing signal is provided by a water turbidity sensor, a water hardness sensor, a weak current type water level detection sensor, a weak current type overflow detection sensor, a weak current type water leakage detection sensor or a weak current type water drainage detection sensor.
9. The sensing circuit of claim 6, wherein the voltage dividing resistor divides the first resistor when the second transistor of the sensing module is turned on or breaks down, such that the voltage at the output terminal varies.
10. A detection circuit according to one of claims 1 to 3, characterized in that the voltage dividing resistor is configured as a thermistor, gas sensor, force sensor, humidity sensor, light sensor or magneto sensor.
11. A detection circuit according to any one of claims 1 to 3, wherein the alternating current signal is a sine wave signal, a square wave signal, a sawtooth wave signal or a triangular wave signal with positive-negative conversion.
12. A control system for a household appliance, characterized in that it comprises:
detection circuit according to one of claims 1 to 11; and
the microcontroller is configured to control the operation of the microcontroller,
wherein the output of the detection circuit is connected to one pin of the microcontroller.
13. The control system of claim 12, further comprising a line synchronization circuit connected to another pin of the microcontroller, the line synchronization circuit being capable of informing at a high-low level whether the ac signal is currently in a positive half cycle or a negative half cycle.
14. The control system of claim 13, wherein the line synchronization circuit controls the output dc voltage by inputting an ac signal to the transistor.
15. Household appliance with a detection circuit according to one of claims 1 to 11 and/or a control system according to one of claims 12 to 14, characterized in that the household appliance comprises a washing machine, dryer, dishwasher, oven, steam box, microwave oven, refrigerator, air conditioner or food processor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320456945.9U CN219496545U (en) | 2023-03-10 | 2023-03-10 | Detection circuit for household appliance, control system and household appliance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320456945.9U CN219496545U (en) | 2023-03-10 | 2023-03-10 | Detection circuit for household appliance, control system and household appliance |
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| Publication Number | Publication Date |
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| CN219496545U true CN219496545U (en) | 2023-08-08 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202320456945.9U Active CN219496545U (en) | 2023-03-10 | 2023-03-10 | Detection circuit for household appliance, control system and household appliance |
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| Country | Link |
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| CN (1) | CN219496545U (en) |
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- 2023-03-10 CN CN202320456945.9U patent/CN219496545U/en active Active
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