Driving control circuit and household appliance

Abstract

The utility model provides a drive control circuit and a household electrical appliance, and the drive control circuit comprises a drive chip, the grounding end of which is connected with a first grounding point; a micro-control unit, wherein the grounding end of the micro-control unit is connected with the second grounding point; the first optical isolation circuit is located between the first connecting end of the micro-control unit and the first connecting end of the driving chip; the second optical isolation circuit is located between the second connecting end of the micro-control unit and the second connecting end of the driving chip; the first end of the temperature sensor is connected with the signal connection end of the micro-control unit, and the second end of the temperature sensor is connected with the second grounding point. Due to the existence of the first optical isolation circuit and the second optical isolation circuit, the first connecting end and the second connecting end are isolated, and the risk of electric shock can be reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to circuit technical field, specifically, relate to a drive control circuit and household electrical appliance. BACKGROUND

[0002] The related technical scheme, taking the household electrical appliance such as dishwasher as an example, includes temperature sensor, the temperature sensor is soaked in the water cup of dishwasher long-term, to detect the liquid temperature in water cup.

[0003] When the temperature sensor is broken, the reference ground of temperature sensor will be short-circuited with the metal shell of dishwasher through liquid.

[0004] Among them, the dishwasher adopts the rectification scheme of full-wave rectification, the grounding point of busbar after full-wave rectification will be directly connected together with the grounding point of weak current control, and the grounding point of weak current control is the reference ground of temperature sensor in the foregoing, and the grounding point of busbar after full-wave rectification has a large pressure difference relative to the ground, so when the temperature sensor is broken, the metal shell of dishwasher will be electrified, and there is the risk of electric shock. UTILITY MODEL CONTENTS

[0005] The utility model aims at at least solving the technical problem that the metal shell of dishwasher will be electrified and there is the risk of electric shock when the temperature sensor is broken in prior art or related art.

[0006] Therefore, the first aspect of the utility model is to provide a drive control circuit.

[0007] The second aspect of the utility model is to provide a household electrical appliance.

[0008] According to the first aspect of the utility model, the utility model provides a drive control circuit, which comprises: a drive chip, a grounding end of the drive chip is connected with a first grounding point; a micro control unit, a grounding end of the micro control unit is connected with a second grounding point; a first optical isolation circuit is located between the first connection end of the micro control unit and the first connection end of the drive chip; a second optical isolation circuit is located between the second connection end of the micro control unit and the second connection end of the drive chip; a temperature sensor, a first end of the temperature sensor is connected with the signal connection end of the micro control unit, and a second end of the temperature sensor is connected with the second grounding point.

[0009] The utility model provides a kind of drive control circuit, in the drive control circuit, utilize first optical isolation circuit and second optical isolation circuit connection driving chip and micro control unit, in this process, driving chip is connected with first ground point, and the ground end of micro control unit is connected with second ground point, due to the existence of first optical isolation circuit and second optical isolation circuit, so that first connecting end and second connecting end are isolated, at this time, when temperature sensor breakdown and damage, the reference ground of temperature sensor can be short-circuited with the metal shell of household appliance by liquid, there is no larger voltage difference between the metal shell of household appliance and ground, therefore, the risk of electric shock can be reduced.

[0010] In addition, the drive control circuit provided by the utility model also has the following additional technical features.

[0011] In some technical solutions, optionally, the drive control circuit further includes: a first resistor connected in series between the signal connection end of the micro control unit and the first end of the temperature sensor; and a first capacitor, with a first end of the first capacitor connected to the signal connection end of the micro control unit and a second end of the first capacitor connected to the second ground point.

[0012] In this technical solution, the first resistor and the first capacitor are arranged to form an RC circuit, and the RC circuit is used for filtering.

[0013] Specifically, the signal output by the temperature sensor is a low-frequency signal, and when the signal is transmitted or interfered externally, high-frequency interference is formed between the first end of the temperature sensor and the micro control unit, which affects the operation of the micro control unit.

[0014] By arranging the RC circuit formed by the first capacitor and the first resistor, the above-mentioned high-frequency interference can be filtered out, and the RC circuit serves as a low-pass filter circuit to improve the reliability of the drive control circuit.

[0015] In some technical solutions, optionally, the drive control circuit further includes: a live wire connection end; a neutral wire connection end; a rectifier circuit, with a first input end of the rectifier circuit connected to the live wire connection end, a second input end of the rectifier circuit connected to the neutral wire connection end, and a second output end of the rectifier circuit connected to the first ground point; a switching power supply, with a first end of the switching power supply connected to a first output end of the rectifier circuit, a second end of the switching power supply connected to the first ground point, a third end of the switching power supply connected to the power supply end of the micro control unit, and a fourth end of the switching power supply connected to the second ground point; and a second resistor connected in series between the first end of the temperature sensor and the third end of the switching power supply.

[0016] In the technical scheme, the live wire connecting end can be understood as a connecting end for connecting a live wire, and the zero line connecting end can be understood as a connecting end for connecting a zero line, the live wire connecting end and the zero line connecting end are arranged to connect the live wire and the zero line, and then the rectifier circuit is connected with the alternating current power grid, so that alternating current is taken from the alternating current power grid to supply the driving control circuit.

[0017] In the technical scheme, the switching power supply can be understood as a power supply capable of controlling whether to output power supply, in the utility model, the switching power supply can be used to take power from the rectifier circuit and supply power to the temperature sensor.

[0018] In the technical scheme, the first grounding point refers to an area directly or indirectly connected with the alternating current power grid, which can also be called hot ground, and there is a voltage difference between the hot ground and the ground, so that there is a risk of electric shock if a human body stands on the ground directly.

[0019] In the technical scheme, the second grounding point refers to a ground not connected with the alternating current power grid, which is isolated from the transformer or components and does not cause harm to the human body, or only exists in a local loop, which is generally not dangerous to the human body, and can also be called cold ground.

[0020] In the technical scheme, the second resistance is arranged to limit the current flowing through the first end of the temperature sensor, which can reduce the working circuit of the temperature sensor and reduce the probability of damage of the temperature sensor due to overcurrent, thereby improving the reliability of the driving control circuit.

[0021] In the technical scheme, the resistance value of the second resistance can be selected according to actual use, and the specific value is not described here.

[0022] In some technical schemes, the rectifier circuit comprises: a first diode, an anode of the first diode being connected with the live wire connecting end; and a first electrolytic capacitor, a first end of the first electrolytic capacitor being connected with a cathode of the first diode and a first end of the switching power supply respectively, and a second end of the first electrolytic capacitor being connected with the zero line connecting end and the first grounding point respectively.

[0023] In the technical scheme, the first diode and the first electrolytic capacitor constitute a rectifier circuit, so that the first grounding point connected with the rectifier circuit and the zero line connecting end can be directly or indirectly connected. In this process, the zero line connected with the zero line connecting end can be used as a system reference ground, and when the temperature sensor is damaged due to breakdown, the reference ground of the temperature sensor is short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground, so that the risk of electric shock can be reduced.

[0024] The first diode is arranged between the live wire connection end and the first end of the switching power supply, so as to limit the signal of the negative half cycle of the alternating current provided by the alternating current network to pass through, at this time, the zero line connection end can be directly connected with the first grounding point, so that the zero line connected by the zero line connection end can be used as the system reference ground, at this time, when the temperature sensor is damaged due to breakdown, the reference ground of the temperature sensor is short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground, so that the risk of electric shock can be reduced.

[0025] In the above technical solution, the first electrolytic capacitor is connected with the cathode of the first diode and the first grounding point, at this time, the alternating current rectified by the first diode can form a stable voltage on the first electrolytic capacitor, and the switching power supply can be supplied with more stable power supply when the power supply is supplied to the switching power supply, so as to ensure the stable output of the switching power supply.

[0026] In the above technical solution, the first diode can allow the signal of the positive half cycle of the alternating current to pass through, and filter out the signal of the negative half cycle of the alternating current.

[0027] In some technical solutions, the rectifier circuit comprises: a first diode, the anode of the first diode is connected with the live wire connection end, and the cathode of the first diode is connected with the first end of the switching power supply; a second diode, the cathode of the second diode is connected with the zero line connection end, and the anode of the second diode is connected with the first grounding point; a first electrolytic capacitor, the first end of the first electrolytic capacitor is connected with the cathode of the first diode, and the second end of the first electrolytic capacitor is connected with the anode of the second diode.

[0028] In the above technical solution, the first diode and the second diode can be used in cooperation to limit the signal of the negative half cycle of the alternating current provided by the alternating current network to pass through, at this time, the zero line connection end can be indirectly connected with the first grounding point, so that the zero line connected by the zero line connection end can be used as the system reference ground, at this time, when the temperature sensor is damaged due to breakdown, the reference ground of the temperature sensor is short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground, so that the risk of electric shock can be reduced.

[0029] Generally, the voltage withstand level of the diode is relatively low, and the single diode is used for rectifying the alternating current, the diode is easy to be broken down, and only the diode with high voltage withstand level can be selected, which increases the manufacturing cost of the drive control circuit.

[0030] In the technical scheme of the utility model, the first diode and the second diode are used in cooperation to share the voltage withstand, the voltage withstand level of the single diode can be reduced, and the risk of diode breakdown can be reduced.

[0031] Meanwhile, the cost of a diode with a higher voltage resistance level is much higher than that of a diode with a lower voltage resistance level, and therefore, in the case of rectification using two diodes, the manufacturing cost of the drive control circuit can be reduced.

[0032] It is worth pointing out that in the case of using two diodes with a moderate voltage resistance level, the manufacturing cost of the drive control circuit can be reduced, and the voltage resistance level of the diode can be improved, and the reliability of the drive control circuit can be improved.

[0033] In the above technical solution, the first electrolytic capacitor is connected to the cathode of the first diode and the anode of the second diode, at this time, the alternating current rectified by the first diode can form a stable voltage on the first electrolytic capacitor, and in the case of supplying power to the switching power supply through the first electrolytic capacitor, the switching power supply can be supplied with more stable power supply, so as to ensure the stable output of the switching power supply.

[0034] In the above technical solution, the first diode and the second diode can allow the signal of the positive half cycle of the alternating current to pass through, and filter out the signal of the negative half cycle of the alternating current.

[0035] In some technical solutions, the rectifier circuit further comprises a first filter capacitor connected in parallel with the first electrolytic capacitor.

[0036] In this technical solution, there may be a clapping-shaped interference on the input side of the rectifier circuit, and the above interference may cause the voltage on the first electrolytic capacitor to fluctuate, thereby affecting the stability of the switching power supply.

[0037] The first filter capacitor provided can filter out the interference on the side of the alternating current network, so as to improve the stability of the drive control circuit.

[0038] In some technical solutions, the drive control circuit further comprises an electric reactor arranged between the first input end of the rectifier circuit and the live wire connection end, and between the second input end of the rectifier circuit and the zero wire connection end; wherein the first end of the electric reactor is connected to the live wire connection end, the second end of the electric reactor is connected to the first input end of the rectifier circuit, the third end of the electric reactor is connected to the second input end of the rectifier circuit, and the fourth end of the electric reactor is connected to the zero wire connection end.

[0039] In this technical solution, the electric reactor provided can filter out the noise from the side of the alternating current network, and by filtering out the noise from the side of the alternating current network, the rectified alternating current after filtering out the noise can be provided to the rectifier circuit, so as to improve the stability of the pulsating direct current after rectification.

[0040] In addition, the electric reactor provided can also filter out the noise from the side of the rectifier circuit to the alternating current network.

[0041] In some embodiments, the drive control circuit further comprises a second filter capacitor, a first end of the second filter capacitor is connected with the live wire connection end, and a second end of the second filter capacitor is connected with the zero wire connection end.

[0042] In the embodiments, the second filter capacitor is arranged to eliminate the differential mode interference by using the second filter capacitor, and in the process, the power supply quality of the alternating current input to the rectifier circuit is improved, so that the switching power supply is provided with less interference power supply, thereby ensuring the stable operation of the temperature sensor.

[0043] In the embodiments, the capacitance value of the second filter capacitor can be determined according to actual needs, and the specific value is not described herein.

[0044] In some embodiments, the drive control circuit further comprises a third filter capacitor, a first end of the third filter capacitor is connected with the second end of the reactor, and a second end of the third filter capacitor is connected with the third grounding point; and a fourth filter capacitor, a first end of the fourth filter capacitor is connected with the third end of the reactor, and a second end of the fourth filter capacitor is connected with the third grounding point; wherein the third grounding point is a grounding point connected with the ground.

[0045] In the embodiments, the third filter capacitor and the fourth filter capacitor are arranged to be connected with the second end of the reactor and the third end of the reactor respectively, and the second end of the reactor and the third end of the reactor are used to be connected with the first input end of the rectifier circuit and the second input end of the rectifier circuit, so that the third filter capacitor and the fourth filter capacitor are used to filter the common mode interference at the first input end of the rectifier circuit and the second input end of the rectifier circuit, and in the process, the power supply quality of the alternating current input to the rectifier circuit is improved, so that the switching power supply is provided with less interference power supply, thereby ensuring the stable operation of the temperature sensor.

[0046] In the embodiments, the capacitance value of the third filter capacitor and the fourth filter capacitor can be determined according to actual needs, and the specific value is not described herein.

[0047] In some embodiments, the switching power supply comprises a transformer, a first end of a first primary coil of the transformer is connected with the first output end of the rectifier circuit, a first end of a first secondary coil of the transformer is connected with the first end of the temperature sensor, a second end of the first secondary coil is connected with the second grounding point, and a first end of a second primary coil of the transformer is connected with the power supply end of the drive chip; and a first switch tube, a first end of the first switch tube is connected with a second end of the first primary coil, and a second end of the first switch tube is connected with the first grounding point.

[0048] In the technical scheme, the switching power supply comprises a transformer and a first switch tube, wherein the first switch tube is arranged in a loop in which the first primary coil is located, so that whether the loop in which the first primary coil is located is connected or not can be controlled through the first switch tube, and in the process, the on-off frequency of the first switch tube can be controlled according to actual power supply needs, so as to provide power supply adapted to the temperature sensor.

[0049] In the process, the switching power supply can provide corresponding power supply according to actual use needs, so as to meet the working needs of different devices.

[0050] In the above technical scheme, the transformer is used to realize the transformation of voltage, so that the first primary coil side can be isolated from the first secondary coil side, thereby improving the safety of power supply.

[0051] In the above technical scheme, the second end of the first switch tube is connected with the first grounding point, that is, the second end of the first switch tube and the rectifier circuit are connected to the same grounding point.

[0052] In some technical schemes, optionally, the switching power supply further comprises a third diode located between the first end of the first secondary coil and the first end of the temperature sensor, wherein the anode of the third diode is connected with the first end of the first secondary coil, and the cathode of the third diode is connected with the first end of the temperature sensor.

[0053] In the technical scheme, the third diode arranged can limit the current flow direction of the first secondary coil, and obviously, the transformer can only supply power from the first primary coil to the first secondary coil, but cannot supply power from the first secondary coil to the first primary coil, thereby ensuring that the switching power supply can provide stable power supply to the temperature sensor.

[0054] In some technical schemes, optionally, the rectifier circuit comprises a fourth diode, wherein the anode of the fourth diode is connected with the zero line connection end; a fifth diode, wherein the anode of the fifth diode is connected with the live wire connection end, the cathode of the fifth diode is connected with the cathode of the fourth diode and the first end of the switching power supply respectively; a sixth diode, wherein the cathode of the sixth diode is connected with the live wire connection end; a seventh diode, wherein the cathode of the seventh diode is connected with the zero line connection end, and the anode of the seventh diode is connected with the anode of the sixth diode and the first grounding point respectively; and a first electrolytic capacitor, wherein the first end of the first electrolytic capacitor is connected with the cathode of the fifth diode, and the second end of the first electrolytic capacitor is connected with the anode of the seventh diode.

[0055] In the technical scheme, the fourth diode, the fifth diode, the sixth diode and the seventh diode constitute a full-wave rectifier circuit, which can convert alternating current provided by an alternating current power grid into direct current, thereby supplying power to the switching power supply.

[0056] Wherein, the voltage at the anode of the sixth diode is changeable after the full-wave rectifier circuit rectifies the alternating current output by the alternating current power grid, so that the first grounding point forms a hot ground. As known from the above, the hot ground refers to an area directly or indirectly connected with the alternating current power grid, and there is a voltage difference between the hot ground and the ground. The voltage difference may be greater than or equal to the human safety voltage of 36 volts, and if a human directly touches the ground while standing on the ground, there is a risk of electric shock.

[0057] Due to the presence of the first optical isolation circuit and the second optical isolation circuit, the first connection end and the second connection end are isolated. In this case, when the temperature sensor is damaged due to breakdown, the reference ground of the temperature sensor will be short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground. Therefore, the risk of electric shock can be reduced.

[0058] In some technical solutions, the drive control circuit further includes a frequency conversion circuit, a first input end of the frequency conversion circuit is connected with the first output end of the rectifier circuit, and a second input end of the frequency conversion circuit is connected with the second output end of the rectifier circuit; and a motor, a first input end of the motor is connected with a first output end of the frequency conversion circuit, and a second input end of the motor is connected with a second output end of the frequency conversion circuit.

[0059] In the technical solution, the drive control circuit further includes the frequency conversion circuit and the motor. Since the frequency conversion circuit is connected between the rectifier circuit and the motor, the frequency conversion circuit can be used to realize the variable frequency driving of the motor. In this process, it can be ensured that the motor can output the required power, thereby meeting the power requirements of the motor in different scenarios.

[0060] In some embodiments, the first optical isolation circuit comprises: a third resistor, a first end of the third resistor being connected to the first connection end of the driving chip; a third capacitor, a first end of the third capacitor being connected to the first end of the third resistor, and a second end of the third capacitor being connected to the first grounding point; a first optocoupler, a first end of the first optocoupler being connected to a second end of the third resistor, a second end of the first optocoupler being connected to the second end of the third capacitor, a third end of the first optocoupler being connected to the first connection end of the micro control unit, and a fourth end of the first optocoupler being connected to the first power supply; a first current-limiting resistor, a first end of the first current-limiting resistor being connected to the first end of the second primary coil of the transformer, and a second end of the first current-limiting resistor being connected to the first end of the first optocoupler; a second current-limiting resistor, being connected in series between the third end of the first optocoupler and the first connection end of the micro control unit; the second optical isolation circuit comprises: a fourth resistor, a second end of the fourth resistor being connected to the second connection end of the micro control unit; a fourth capacitor, a first end of the fourth capacitor being connected to the second end of the fourth resistor, and a second end of the fourth capacitor being connected to the second grounding point; a second optocoupler, a first end of the second optocoupler being connected to a first end of the fourth resistor, a second end of the second optocoupler being connected to the second end of the fourth capacitor, a third end of the second optocoupler being connected to the second connection end of the driving chip, and a fourth end of the second optocoupler being connected to the first end of the second primary coil of the transformer; a third current-limiting resistor, a first end of the third current-limiting resistor being connected to the first power supply, and a second end of the third current-limiting resistor being connected to the first end of the second optocoupler; and a fourth current-limiting resistor, being connected in series between the third end of the second optocoupler and the second connection end of the driving chip.

[0061] In the technical solution, the first optocoupler is arranged to realize data transmission and isolate the first grounding point and the second grounding point, thereby avoiding direct connection between the first grounding point and the second grounding point, and when the reference ground of the temperature sensor is short-circuited with the metal shell of the household appliance through the liquid in the case of breakdown of the temperature sensor, there is no large voltage difference between the metal shell of the household appliance and the ground, and thus the risk of electric shock is reduced.

[0062] In the above technical solution, the third resistor and the third capacitor form an RC filter circuit, which can filter out high-frequency interference and allow low-frequency signals to pass through, thereby eliminating signal disturbance caused by high-frequency interference when the driving chip and the micro control unit transmit data, and affecting the accuracy of the transmitted data.

[0063] In the technical scheme, the first current-limiting resistor is arranged to increase the resistance value of the loop in which the second primary coil of the transformer and the first end of the first optocoupler are located, thereby reducing the current value flowing through the loop, so as to limit the working current flowing through the first optocoupler, and in the case of limiting the working current flowing through the first optocoupler, the probability of damage of the first optocoupler due to overcurrent is reduced, thereby improving the reliability of the drive control circuit.

[0064] In addition, the second current-limiting resistor is arranged to limit the current input by the first connection end of the micro control unit, thereby protecting the micro control unit, and in this process, the probability of damage of the micro control unit due to overcurrent is reduced, thereby improving the reliability of the drive control circuit.

[0065] In the technical scheme, the second optocoupler is arranged to isolate the first grounding point and the second grounding point while realizing data transmission, thereby avoiding the direct connection between the first grounding point and the second grounding point, and in this process, when the temperature sensor is damaged due to breakdown, the reference ground of the temperature sensor is short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground, so the risk of electric shock is reduced.

[0066] In the technical scheme, the fourth resistor and the fourth capacitor are arranged to form an RC filter circuit, which can filter out high-frequency interference and allow low-frequency signals to pass through, so that the signal disturbance caused by high-frequency interference during data transmission between the drive chip and the micro control unit is eliminated, and the accuracy of the transmitted data is affected.

[0067] In the technical scheme, the third current-limiting resistor is arranged to increase the resistance value of the loop in which the first end of the first optocoupler and the first power supply are located, thereby reducing the current value flowing through the loop, so as to limit the working current flowing through the second optocoupler, and in the case of limiting the working current flowing through the second optocoupler, the probability of damage of the second optocoupler due to overcurrent is reduced, thereby improving the reliability of the drive control circuit.

[0068] In addition, the fourth current-limiting resistor is arranged to limit the current input by the second connection end of the drive chip, thereby protecting the drive chip, and in this process, the probability of damage of the drive chip due to overcurrent is reduced, thereby improving the reliability of the drive control circuit.

[0069] According to a second aspect of the present application, the present application provides a household appliance, comprising: the drive control circuit according to any one of the first aspect.

[0070] Additional aspects and advantages of the present application will be given in part in the following description and part will become apparent to those skilled in the art from the following description, or can be learned by the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0071] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the following drawings, in which:

[0072] Figure 1 A topological schematic diagram of a drive control circuit in an embodiment of the present application is shown;

[0073] Figure 2 A topological schematic diagram of a drive control circuit in an embodiment of the present application is shown;

[0074] Figure 3 A structure schematic diagram of a dishwasher in an embodiment of the present application is shown;

[0075] Figure 4 A connection schematic diagram of a first grounding point and a second grounding point in an embodiment of the present application is shown;

[0076] Figure 5 A connection schematic diagram of a distribution box in an embodiment of the present application is shown;

[0077] Figure 6 A topological schematic diagram of a full-wave rectification in an embodiment of the present application is shown;

[0078] Figure 7 A topological schematic diagram of a half-wave rectification in an embodiment of the present application is shown;

[0079] Figure 8 An input / output schematic diagram of a full-wave rectification in an embodiment of the present application is shown;

[0080] Figure 9 An input / output schematic diagram of a half-wave rectification in an embodiment of the present application is shown;

[0081] Figure 10 A topological schematic diagram of a drive control circuit in an embodiment of the present application is shown;

[0082] Figure 11 A topological schematic diagram of a drive control circuit in an embodiment of the present application is shown.

[0083] Wherein, Figures 1 to 7 , Figure 10 and Figure 11 The correspondence between the reference signs and the component names in the drawings is as follows:

[0084] 100 drive control circuit, 102 drive chip, 104 micro control unit, 106 first optical isolation circuit, 108 second optical isolation circuit, 110 temperature sensor, 112 live wire connection end, 114 zero line connection end, 116 rectifier circuit, 118 switching power supply, PGND first ground point, GND second ground point, D1 first diode, EC1 first electrolytic capacitor, D2 second diode, GC1 first filter capacitor, L1 reactor, GC2 second filter capacitor, GC3 third filter capacitor, GC4 fourth filter capacitor, PE third ground point, T transformer, Q1 first switch tube, D3 third diode, R1 first resistor, C1 first capacitor, R2 second resistor, D4 fourth diode, D5 fifth diode, D6 sixth diode, D7 seventh diode, R3 third resistor, C3 third capacitor, G1 first optocoupler, XR1 first current limiting resistor, XR2 second current limiting resistor, R4 fourth resistor, C4 fourth capacitor, G2 second optocoupler, XR3 third current limiting resistor, XR4 fourth current limiting resistor, 300 dish washing machine, 301 metal shell, 302 metal inner container, 303 upper spray arm, 304 lower spray arm, 305 water inlet pipe, 306 water inlet valve, 307 water cup, 308 circulating pump, 309 drain pump, 310 power line, 311 water faucet, 500 distribution box, 502 electrical equipment, VCC first power supply, 120 frequency conversion circuit, M motor. DETAILED DESCRIPTION

[0085] In order to enable the above aspects, features and advantages of the present application to be clearer, the following further describes the present application with reference to the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0086] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be implemented in other manners different from those described herein, therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0087] In one embodiment of the present application, as Figure 1 , Figure 2 , Figure 10 and Figure 11As shown, a driving control circuit 100 is provided, comprising: a driving chip 102, a ground end of the driving chip 102 being connected with a first grounding point PGND; a micro control unit 104, a ground end of the micro control unit 104 being connected with a second grounding point GND; a first optical isolation circuit 106, located between a first connection end of the micro control unit 104 and a first connection end of the driving chip 102; a second optical isolation circuit 108, located between a second connection end of the micro control unit 104 and a second connection end of the driving chip 102; and a temperature sensor 110, a first end of the temperature sensor 110 being connected with a signal connection end of the micro control unit 104, and a second end of the temperature sensor 110 being connected with the second grounding point GND.

[0088] The utility model provides a kind of driving control circuit, in the driving control circuit, first optical isolation circuit 106 and second optical isolation circuit 108 are connected driving chip 102 and micro control unit 104, in this process, driving chip 102 is connected with first grounding point PGND, and the ground end of micro control unit 104 is connected with second grounding point GND, due to the existence of first optical isolation circuit 106 and second optical isolation circuit 108, so that first connection end and second connection end are isolated, at this time, when temperature sensor 110 breakdown and damage, the reference ground of temperature sensor 110 can be short-circuited by liquid and the metal shell of household appliance, there is no larger voltage difference between the metal shell of household appliance and ground, therefore, the risk of electric shock can be reduced.

[0089] In some embodiments, optionally, the driving control circuit 100 further comprises: a first resistor R1, which is connected in series between the signal connection end of the micro control unit 104 and the first end of the temperature sensor 110; and a first capacitor C1, a first end of the first capacitor C1 being connected with the signal connection end of the micro control unit 104, and a second end of the first capacitor C1 being connected with the second grounding point GND.

[0090] In this embodiment, the first resistor R1 and the first capacitor C1 form an RC circuit, and the RC circuit is used for filtering.

[0091] Specifically, the signal output by the temperature sensor 110 is a low-frequency signal, and when the signal is transmitted or interfered by an external interference, a high-frequency interference is formed between the first end of the temperature sensor 110 and the micro control unit 104, which affects the operation of the micro control unit 104.

[0092] By setting the RC circuit composed of the first capacitor C1 and the first resistor R1, the above-mentioned high-frequency interference can be filtered out, and the RC circuit is used as a low-pass filter circuit to improve the reliability of the driving control circuit.

[0093] In some embodiments, optionally, the drive control circuit further comprises: a live wire connection end 112; a zero wire connection end 114; a rectifier circuit 116, a first input end of the rectifier circuit 116 is connected with the live wire connection end 112, a second input end of the rectifier circuit 116 is connected with the zero wire connection end 114, a second output end of the rectifier circuit 116 is connected with the first grounding point PGND; a switching power supply 118, a first end of the switching power supply 118 is connected with a first output end of the rectifier circuit 116, a second end of the switching power supply 118 is connected with the first grounding point PGND, a third end of the switching power supply 118 is connected with a power supply end of the micro control unit 104, a fourth end of the switching power supply 118 is connected with the second grounding point GND; a second resistor R2, which is connected in series between a first end of the temperature sensor 110 and the third end of the switching power supply 118.

[0094] In the above embodiment, the live wire connection end 112 can be understood as a connection end for connecting a live wire, at the same time, the zero wire connection end 114 can be understood as a connection end for connecting a zero wire, the set live wire connection end 112 and zero wire connection end 114 can connect the live wire and the zero wire, and then connect the rectifier circuit 116 with the alternating current power grid, so as to take alternating current from the alternating current power grid for the drive control circuit.

[0095] In the above embodiment, the switching power supply 118 can be understood as a power supply which can control whether to output power supply, in the utility model, the switching power supply 118 can be used to take power from the rectifier circuit 116 and supply power to the temperature sensor 110.

[0096] In the above embodiment, the first grounding point PGND refers to an area directly or indirectly connected with the alternating current power grid, which can also be called hot ground, and there is a voltage difference between the hot ground and the ground, so if a human body stands on the ground and directly triggers, there is a risk of electric shock.

[0097] In the above embodiment, the second grounding point GND refers to a ground without connection with the alternating current power grid, which is an isolated ground for human body or a local loop, and is generally not dangerous to human body, which can also be called cold ground.

[0098] In the above embodiment, by setting the second resistor R2, the second resistor R2 is used to limit the current flowing through the first end of the temperature sensor 110, in this process, the working circuit of the temperature sensor 110 can be reduced, the probability of damage of the temperature sensor 110 due to overcurrent is reduced, and the reliability of the drive control circuit is improved.

[0099] In the above embodiment, the resistance value of the second resistor R2 can be valued according to actual use needs, and the specific value is not described here.

[0100] Wherein, the connection position between the rectifier circuit 116 and the switching power supply 118 is denoted as VBUS, RX denotes receiving data, and TX denotes transmitting data.

[0101] In some embodiments, the rectifier circuit 116 comprises a first diode D1, an anode of the first diode D1 is connected with the live wire connection end 112; a first electrolytic capacitor EC1, a first end of the first electrolytic capacitor EC1 is connected with a cathode of the first diode D1 and a first end of the switching power supply 118 respectively, and a second end of the first electrolytic capacitor EC1 is connected with the zero line connection end 114 and the first grounding point PGND respectively.

[0102] In this embodiment, the first diode D1 and the first electrolytic capacitor EC1 constitute a half-wave rectifier circuit, so that the first grounding point PGND connected with the half-wave rectifier circuit and the zero line connection end 114 can be directly or indirectly connected. In this process, the zero line connected with the zero line connection end 114 can be used as the system reference ground. At this time, when the temperature sensor 110 is damaged due to breakdown, the reference ground of the temperature sensor 110 will be short-circuited through the liquid and the metal shell of the household appliance, and there is also no large voltage difference between the metal shell of the household appliance and the ground, so the risk of electric shock can be reduced.

[0103] In this embodiment, the first diode D1 is arranged between the live wire connection end 112 and the first end of the switching power supply 118, so as to limit the signal of the negative half cycle of the alternating current provided by the alternating current grid to pass through. At this time, the zero line connection end 114 can be directly connected with the first grounding point PGND, so the zero line connected with the zero line connection end 114 can be used as the system reference ground. At this time, when the temperature sensor 110 is damaged due to breakdown, the reference ground of the temperature sensor 110 will be short-circuited through the liquid and the metal shell of the household appliance, and there is also no large voltage difference between the metal shell of the household appliance and the ground, so the risk of electric shock can be reduced.

[0104] In the above embodiment, the first electrolytic capacitor EC1 is connected with the cathode of the first diode D1 and the first grounding point PGND respectively. At this time, the alternating current rectified by the first diode D1 can form a stable voltage on the first electrolytic capacitor EC1. When the first electrolytic capacitor EC1 supplies power to the switching power supply 118, the switching power supply 118 can be supplied with more stable power, so as to ensure that the switching power supply 118 stably outputs power.

[0105] In the above embodiment, the first diode D1 can allow the signal of the positive half cycle of the alternating current to pass through, and filter out the signal of the negative half cycle of the alternating current.

[0106] In some embodiments, optionally, the rectifier circuit 116 comprises: a first diode D1, an anode of the first diode D1 is connected with the live wire connection end 112, and a cathode of the first diode D1 is connected with a first end of the switching power supply 118; a second diode D2, a cathode of the second diode D2 is connected with the zero wire connection end 114, and an anode of the second diode D2 is connected with the first grounding point PGND; and a first electrolytic capacitor EC1, a first end of the first electrolytic capacitor EC1 is connected with the cathode of the first diode D1, and a second end of the first electrolytic capacitor EC1 is connected with the anode of the second diode D2.

[0107] In this embodiment, the first diode D1, the second diode D2 and the first electrolytic capacitor EC1 constitute a half-wave rectifier circuit, and the first diode D1 and the second diode D2 can be used in combination to limit the passage of signals of the negative half cycle of the alternating current provided by the alternating current grid, at this time, the zero wire connection end 114 can be indirectly connected with the first grounding point PGND, and thus the zero wire connected with the zero wire connection end 114 can be used as the system reference ground, at this time, when the temperature sensor 110 is damaged due to breakdown, the reference ground of the temperature sensor 110 can be short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground, and thus the risk of electric shock can be reduced.

[0108] Generally, the voltage withstand level of a diode is relatively low, and when a single diode is used for rectification, the diode is easily broken down, and only a diode with a high voltage withstand level can be selected, which increases the manufacturing cost of the drive control circuit.

[0109] In the embodiment of the utility model, the first diode D1 and the second diode D2 are used in combination to share the voltage withstand, the voltage withstand level of a single diode can be reduced, and thus the risk of breakdown of the diode can be reduced.

[0110] Meanwhile, the cost of a diode with a high voltage withstand level is much higher than that of a diode with a low voltage withstand level, and thus when two diodes are used for rectification, the manufacturing cost of the drive control circuit can be reduced.

[0111] It is worth pointing out that when two diodes with a moderate voltage withstand level are selected and used in combination, the manufacturing cost of the drive control circuit can be reduced, and the voltage withstand level of the diode can be improved, and the reliability of the drive control circuit can be improved.

[0112] In the above embodiment, the first electrolytic capacitor EC1 is connected to the cathode of the first diode D1 and the anode of the second diode D2, respectively. At this time, the alternating current rectified by the first diode D1 can form a stable voltage on the first electrolytic capacitor EC1. In the case of supplying power to the switching power supply 118 through the first electrolytic capacitor EC1, more stable power supply can be provided to the switching power supply 118, so as to ensure the stable output of the switching power supply 118.

[0113] In the above embodiment, the first diode D1 and the second diode D2 can allow the signal of the positive half cycle of the alternating current to pass through, and filter out the signal of the negative half cycle of the alternating current.

[0114] In some embodiments, optionally, the rectifier circuit 116 further comprises a first filter capacitor GC1, and the first filter capacitor GC1 is connected in parallel with the first electrolytic capacitor EC1.

[0115] In this embodiment, there may be a clapper-shaped interference on the input side of the rectifier circuit 116. The above interference can cause the voltage on the first electrolytic capacitor EC1 to fluctuate, thereby affecting the stability of the switching power supply 118.

[0116] The first filter capacitor GC1 can filter out the interference on the alternating current grid side, so as to improve the stability of the driving control circuit.

[0117] In some embodiments, optionally, the driving control circuit further comprises an inductor L1, which is arranged between the first input end of the rectifier circuit 116 and the live wire connection end 112, and between the second input end of the rectifier circuit 116 and the zero line connection end 114. The first end of the inductor L1 is connected to the live wire connection end 112, the second end of the inductor L1 is connected to the first input end of the rectifier circuit 116, the third end of the inductor L1 is connected to the second input end of the rectifier circuit 116, and the fourth end of the inductor L1 is connected to the zero line connection end 114.

[0118] In this embodiment, the inductor L1 can filter out the noise from the alternating current grid side. By filtering out the noise from the alternating current grid side, the rectified pulsating direct current can be provided to the rectifier circuit 116, so as to improve the stability of the rectified pulsating direct current.

[0119] In addition, the inductor L1 can also filter out the noise from the rectifier circuit 116 side to the alternating current grid.

[0120] In some embodiments, optionally, the driving control circuit further comprises a second filter capacitor GC2, and the first end of the second filter capacitor GC2 is connected to the live wire connection end 112, and the second end of the second filter capacitor GC2 is connected to the zero line connection end 114.

[0121] In the embodiment, the second filter capacitor GC2 is arranged to eliminate the differential mode interference by using the second filter capacitor GC2, in the process, the power supply quality of the AC power input to the rectifier circuit 116 can be improved, so as to provide less interference power supply for the switching power supply 118, thereby ensuring the stable operation of the temperature sensor 110.

[0122] In the above embodiment, the capacitance value of the second filter capacitor GC2 can be valued according to actual use, and the specific value is not described here.

[0123] In some embodiments, optionally, the drive control circuit further comprises: a third filter capacitor GC3, a first end of the third filter capacitor GC3 is connected with the second end of the reactor L1, and a second end of the third filter capacitor GC3 is connected with the third grounding point PE; a fourth filter capacitor GC4, a first end of the fourth filter capacitor GC4 is connected with the third end of the reactor L1, and a second end of the fourth filter capacitor GC4 is connected with the third grounding point PE; wherein the third grounding point PE is a grounding point connected with the ground.

[0124] In the embodiment, the third filter capacitor GC3 and the fourth filter capacitor GC4 are arranged to be connected with the second end of the reactor L1 and the third end of the reactor L1 respectively, and the second end of the reactor L1 and the third end of the reactor L1 are used to be connected with the first input end of the rectifier circuit 116 and the second input end of the rectifier circuit 116, therefore, the third filter capacitor GC3 and the fourth filter capacitor GC4 can be used to filter the common mode interference at the first input end of the rectifier circuit 116 and the second input end of the rectifier circuit 116, in the process, the power supply quality of the AC power input to the rectifier circuit 116 can be improved, so as to provide less interference power supply for the switching power supply 118, thereby ensuring the stable operation of the temperature sensor 110.

[0125] In the above embodiment, the capacitance value of the third filter capacitor GC3 and the fourth filter capacitor GC4 can be valued according to actual use, and the specific value is not described here.

[0126] In some embodiments, optionally, the switching power supply 118 comprises: a transformer T, a first end of a first primary coil of the transformer T is connected with the first output end of the rectifier circuit 116, a first end of a first secondary coil of the transformer T is connected with the first end of the temperature sensor 110, a second end of the first secondary coil is connected with the second grounding point GND, and a first end of a second primary coil of the transformer T is connected with the power supply end of the drive chip 102; a first switch tube Q1, a first end of the first switch tube Q1 is connected with a second end of the first primary coil, and a second end of the first switch tube Q1 is connected with the first grounding point PGND.

[0127] In the embodiment, the switching power supply 118 comprises the transformer T and the first switch tube Q1, wherein the first switch tube Q1 is arranged in the loop where the first primary coil is located, so that whether the loop where the first primary coil is located is connected can be controlled by the first switch tube Q1, and in the process, the on-off frequency of the first switch tube Q1 can be controlled according to the actual power supply requirement, thereby providing the temperature sensor 110 with power supply adapted to the temperature sensor 110.

[0128] In the process, the switching power supply 118 can provide corresponding power supply according to the actual use requirement, so as to meet the working requirement of different devices.

[0129] In the above embodiment, the transformer T is used to realize the transformation of voltage, and the first primary coil side can be isolated from the first secondary coil side, thereby improving the safety of power supply.

[0130] In the above embodiment, the second end of the first switch tube Q1 is connected with the first grounding point PGND, that is, the second end of the first switch tube Q1 and the rectifier circuit 116 are connected to the same grounding point.

[0131] In the above embodiment, the motor represents the voltage provided by the second primary coil of the transformer T, the Inverter RX of the driving chip 102 is connected with the Inverter RX of the first optical isolation circuit 106, the Inverter TX of the driving chip 102 is connected with the Inverter TX of the second optical isolation circuit 108, and the MCU RX of the micro control unit 104 is connected with the MCU RX of the second optical isolation circuit 108, and the MCU TX of the micro control unit 104 is connected with the MCU TX of the first optical isolation circuit 106.

[0132] In the above embodiment, the cold ground is not connected with the AC power grid, and after the optical coupling isolation, it will not cause harm to the human body, and when the breakdown occurs in the temperature sensor, the reference ground of the temperature sensor is directly short-circuited with the metal shell (ground) in the dishwasher through water, and since there is no large pressure difference (less than 36V) between the cold ground and the ground, it is relatively safe. At this time, even if the power line ground is in poor contact, the user directly touches the dishwasher shell, which is equivalent to touching the cold ground, and there is no risk of electric shock.

[0133] In some embodiments, optionally, the switching power supply 118 further comprises a third diode D3 located between the first end of the first secondary coil and the first end of the temperature sensor 110, wherein the anode of the third diode D3 is connected with the first end of the first secondary coil, and the cathode of the third diode D3 is connected with the first end of the temperature sensor 110.

[0134] In this embodiment, the third diode D3 is arranged to limit the current flow direction of the first secondary coil, and obviously, the transformer T can only supply power from the first primary coil to the first secondary coil, but cannot supply power from the first secondary coil to the first primary coil, thereby ensuring that the switching power supply 118 can provide stable power supply to the temperature sensor 110.

[0135] In some embodiments, optionally, the rectifier circuit 116 comprises: a fourth diode D4, an anode of the fourth diode D4 being connected with the zero line connection end 114; a fifth diode D5, an anode of the fifth diode D5 being connected with the live line connection end 112, a cathode of the fifth diode D5 being connected with a cathode of the fourth diode D4 and a first end of the switching power supply 118 respectively; a sixth diode D6, a cathode of the sixth diode D6 being connected with the live line connection end 112; a seventh diode D7, a cathode of the seventh diode D7 being connected with the zero line connection end 114, an anode of the seventh diode D7 being connected with an anode of the sixth diode D6 and the first ground point PGND respectively; and a first electrolytic capacitor EC1, a first end of the first electrolytic capacitor EC1 being connected with the cathode of the fifth diode D5, a second end of the first electrolytic capacitor EC1 being connected with the anode of the seventh diode D7.

[0136] In this embodiment, the fourth diode D4, the fifth diode D5, the sixth diode D6 and the seventh diode D7 constitute a full-wave rectifier circuit, which can convert the alternating current provided by the alternating current power grid into direct current, thereby supplying power to the switching power supply 118.

[0137] Among them, after the full-wave rectifier circuit rectifies the alternating current output by the alternating current power grid, the voltage at the anode of the sixth diode D6 is variable, so that the first ground point PGND forms a hot ground. As known from the above, the hot ground refers to an area directly or indirectly connected with the alternating current power grid, and there is a voltage difference between the hot ground and the ground. The above-mentioned voltage difference may be greater than or equal to the human body safety voltage of 36 volts, and if a human body stands on the ground and directly touches it, there is a risk of electric shock.

[0138] Due to the existence of the first optical isolation circuit 106 and the second optical isolation circuit 108, the first connection end and the second connection end are isolated. At this time, when the temperature sensor 110 is damaged due to breakdown, the reference ground of the temperature sensor 110 will be short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground. Therefore, the risk of electric shock can be reduced.

[0139] In some embodiments, optionally, the drive control circuit further comprises: a frequency conversion circuit 120, a first input end of the frequency conversion circuit 120 is connected with the first output end of the rectifier circuit 116, and a second input end of the frequency conversion circuit 120 is connected with the second output end of the rectifier circuit 116; and a motor M, a first input end of the motor M is connected with a first output end of the frequency conversion circuit 120, and a second input end of the motor M is connected with a second output end of the frequency conversion circuit 120.

[0140] In this embodiment, the drive control circuit further comprises the frequency conversion circuit 120 and the motor M, since the frequency conversion circuit 120 is connected between the rectifier circuit 116 and the motor M, the frequency conversion circuit 120 can be used to realize the frequency conversion driving of the motor M, and in this process, it can be ensured that the motor M can output the required power, thereby meeting the power requirements of the motor M in different scenarios.

[0141] In some embodiments, optionally, the first optical isolation circuit 106 comprises: a third resistor R3, a first end of the third resistor R3 is connected with the first connection end of the drive chip 102; a third capacitor C3, a first end of the third capacitor C3 is connected with the first end of the third resistor R3, and a second end of the third capacitor C3 is connected with the first grounding point PGND; a first optocoupler G1, a first end of the first optocoupler G1 is connected with a second end of the third resistor R3, a second end of the first optocoupler G1 is connected with a second end of the third capacitor C3, a third end of the first optocoupler G1 is connected with the first connection end of the micro control unit 104, and a fourth end of the first optocoupler G1 is connected with the first power supply VCC; a first current limiting resistor XR1, a first end of the first current limiting resistor XR1 is connected with the first end of the second primary coil of the transformer T, and a second end of the first current limiting resistor XR1 is connected with the first end of the first optocoupler G1; a second current limiting resistor XR2, which is connected in series between the third end of the first optocoupler G1 and the first connection end of the micro control unit 104; the second optical isolation circuit 108 comprises: a fourth resistor R4, a second end of the fourth resistor R4 is connected with the second connection end of the micro control unit 104; a fourth capacitor C4, a first end of the fourth capacitor C4 is connected with the second end of the fourth resistor R4, and a second end of the fourth capacitor C4 is connected with the second grounding point GND; a second optocoupler G2, a first end of the second optocoupler G2 is connected with a first end of the fourth resistor R4, a second end of the second optocoupler G2 is connected with a second end of the fourth capacitor C4, a third end of the second optocoupler G2 is connected with the second connection end of the drive chip 102, and a fourth end of the second optocoupler G2 is connected with the first end of the second primary coil of the transformer T; a third current limiting resistor XR3, a first end of the third current limiting resistor XR3 is connected with the first power supply VCC, and a second end of the third current limiting resistor XR3 is connected with the first end of the second optocoupler G2; a fourth current limiting resistor XR4, which is connected in series between the third end of the second optocoupler G2 and the second connection end of the drive chip 102.

[0142] In the embodiment, the first optical coupler G1 is arranged to realize data transmission, and meanwhile, the first grounding point PGND and the second grounding point GND are isolated, thereby avoiding direct connection between the first grounding point PGND and the second grounding point GND. In this process, when the temperature sensor 110 is damaged due to breakdown, the reference ground of the temperature sensor 110 is short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground, so that the risk of electric shock can be reduced.

[0143] In the above embodiment, the third resistor R3 and the third capacitor C3 are arranged to form an RC filter circuit, which can filter out high-frequency interference and allow low-frequency signals to pass through, so that the signal disturbance caused by high-frequency interference when the driving chip 102 and the micro control unit 104 transmit data can be eliminated, and the accuracy of the transmitted data can be affected.

[0144] In the above embodiment, the first current limiting resistor XR1 is arranged to increase the resistance value of the loop in which the second primary coil of the transformer T and the first end of the first optical coupler G1 are located, thereby reducing the current value flowing through the loop, so as to limit the working current flowing through the first optical coupler G1. In the case of limiting the working current flowing through the first optical coupler G1, the probability of damage of the first optical coupler G1 due to overcurrent can be reduced, thereby improving the reliability of the driving control circuit.

[0145] In addition, the second current limiting resistor XR2 is arranged to limit the current input by the first connection end of the micro control unit 104 by using the second current limiting resistor XR2, thereby protecting the micro control unit 104. In this process, the probability of damage of the micro control unit 104 due to overcurrent can be reduced, thereby improving the reliability of the driving control circuit.

[0146] In the above embodiment, the second optical coupler G2 is arranged to realize data transmission, and meanwhile, the first grounding point PGND and the second grounding point GND are isolated, thereby avoiding direct connection between the first grounding point PGND and the second grounding point GND. In this process, when the temperature sensor 110 is damaged due to breakdown, the reference ground of the temperature sensor 110 is short-circuited with the metal shell of the household appliance through the liquid, and there is no large voltage difference between the metal shell of the household appliance and the ground, so that the risk of electric shock can be reduced.

[0147] In the above embodiment, the fourth resistor R4 and the fourth capacitor C4 are arranged to form an RC filter circuit, which can filter out high-frequency interference and allow low-frequency signals to pass through, so that the signal disturbance caused by high-frequency interference when the driving chip 102 and the micro control unit 104 transmit data can be eliminated, and the accuracy of the transmitted data can be affected.

[0148] In the above embodiment, by setting the third current limiting resistor XR3, the resistance value of the loop in which the first power supply and the first end of the second optocoupler G2 are located can be reduced, thereby reducing the current flowing through the above-mentioned loop, so as to limit the working current flowing through the second optocoupler G2, and in the case of limiting the working current flowing through the second optocoupler G2, the probability of damage of the second optocoupler G2 due to overcurrent can be reduced, thereby improving the reliability of the drive control circuit.

[0149] In addition, by setting the fourth current limiting resistor XR4, the current input to the second connection end of the drive chip 102 is limited by the fourth current limiting resistor XR4, thereby playing a role in protecting the drive chip 102, and in this process, the probability of damage of the drive chip 102 due to overcurrent can be reduced, thereby improving the reliability of the drive control circuit.

[0150] In some embodiments of the present application, the household appliance is a dishwasher, as shown in the accompanying drawings, the dishwasher 300 includes a metal shell 301, a metal inner container 302, an upper spray arm 303, a lower spray arm 304, a water inlet pipe 305, a water inlet valve 306, a water cup 307, a circulating pump 308, a drain pump 309, a power cord 310 and a water faucet 311. Figure 3

[0151] Among them, the water faucet 311 is stored in the water cup 307 after water inlet, and the water cup 307 has water, because the temperature sensor 110 in the water cup 307 is immersed in water for a long time to detect the water temperature, specifically, the temperature sensor 110 has two lead wires, one of which is a reference ground, that is, the second grounding point GND in the present application. When the temperature sensor 110 is broken, its reference ground will be directly connected with the metal inner container 302 of the dishwasher 300 through the water in the water cup 307, and the metal inner container 302 and the metal shell 301 are directly connected together, belonging to the same conductor.

[0152] And the power cord 310 of the dishwasher 300 generally adopts single-phase three-wire system, one of which is a grounding wire, but some users' sockets do not have a real ground or have problems such as poor grounding during use, which will cause the grounding effect to fail, because most household appliances use non-isolation scheme, as shown in the accompanying drawings, the non-isolation scheme, that is, the "hot ground" PGND and the "cold ground" GND are connected through a 0Ω resistor, which belongs to one ground and does not play a role in isolation protection. Figure 4

[0153] And the "hot ground" is the bus ground after full-wave rectification, which is indirectly connected with alternating current, and there is a voltage difference between the hot ground and the ground, if the user directly triggers the dishwasher metal shell standing on the ground, there is a risk of electric shock.

[0154] Figure 5 ​​The utility model discloses a connection diagram of distribution box, wherein, the connection diagram between the connection between the zero line, the fire line, the ground wire in distribution box and the electric equipment is shown, such as Figure 5 The zero line N, the fire line L, the ground wire in distribution box 500 are connected with the electric equipment 502 respectively, wherein, the electric equipment 502 can be the household appliance mentioned in the utility model, the zero line N is connected to the ground after being connected with the ground.

[0155] Figure 6 The utility model discloses a topology schematic diagram of rectifying alternating current by full wave rectifier circuit, Figure 7 The utility model discloses a topology schematic diagram of rectifying alternating current by half wave rectifier circuit, Figure 8 The utility model discloses a schematic diagram of input and output signal when rectifying alternating current by full wave rectifier circuit, Figure 9 The utility model discloses a schematic diagram of input and output signal when rectifying alternating current by half wave rectifier circuit.

[0156] As Figure 6 , Figure 7 , Figure 8 And Figure 9 Show, full wave rectification is the alternating voltage on zero fire line through four rectifier diodes or rectifier bridge stack, full wave rectification into direct current, again through bus capacitor filtering.Due to the bus ground after full wave rectification belongs to hot ground, indirectly and the alternating current grid is connected, and there is voltage difference between the real ground, sometimes voltage difference is greater than the human body safety voltage 36V.

[0157] And the reference ground hot ground and cold ground of the common electric control board of dishwasher 300 are the same ground, often directly connected together, or through 0Ω resistance single-point grounding, equivalent to the cold ground also exists the problem of large voltage difference to the ground.

[0158] Because of the special function of dishwasher 300, there is a water cup 307 in the water inlet system to store water, and a temperature sensor 110 exists in the water cup 307 for water temperature detection in the system, and the reference ground of the temperature sensor 110 is directly short-circuited with the internal metal shell (ground) of the dishwasher through water when breakdown occurs inside the temperature sensor 110.Because the common dishwasher system is a non-isolation scheme, the hot ground and the cold ground are directly connected, equivalent to the cold ground also exists voltage difference to the ground, if the human body stands on the ground and directly triggers, there is the risk of electric shock.

[0159] Because the ground wire in the dishwasher 300 is connected with the metal shell 301 of the dishwasher, the shell belongs to grounding, at this time, if the shell grounding is good, the leakage current will flow away through the ground wire of the shell through the ground, but some power line sockets do not have ground wire, or the ground wire is loose or the ground resistance is too large during long-term use, if the user touches the metal shell of the dishwasher with hand, there is the risk of electric shock.

[0160] In this embodiment, if Figure 5 As shown, a half-wave rectifier circuit is used to set the grid's neutral line (N) as the reference ground for the electronic control board. Since the grid's neutral point (N) line and the ground line are directly connected, there's no significant voltage difference between the N line and the ground; ideally, the voltage difference is 0V. In this case, the inverter ground and the main control ground in dishwasher 300's electronic control system both use the neutral line (N) as the reference ground. In the event of a short circuit in temperature sensor 110, even if the dishwasher's power cord ground is disconnected or the grounding resistance is excessive, the voltage difference remains at 0V due to the equipotentiality of the metal housing and the reference ground of the electronic control board. In this case, a user standing on the ground and touching the dishwasher's metal housing directly poses no risk of electric shock.

[0161] Therefore, changing the rectifier circuit 116 from full-wave rectification to half-wave rectification and using the neutral line N of the power grid system as the reference ground of the electronic control system can help meet the leakage safety regulations.

[0162] In the above embodiment, the full-wave rectification is changed to half-wave rectification, and the efficiency η of the switching power supply 118 is reduced from about 70% to 48.5%. Therefore, the current and voltage of the rectifier diode and the bus capacitor need to be reselected as follows:

[0163] 1) Rectifier diode withstand voltage selection:

[0164] When selecting rectifier diodes, you should choose according to the maximum operating voltage. After adding filter capacitors, the bus voltage is not much different from full-wave rectification, and the voltage fluctuation value increases.

[0165] (Reserve 1.5 times the withstand voltage)

[0166] Therefore, the bus capacitor voltage resistance value and the rectifier diode voltage resistance value are 1.5×Vbusmax.

[0167] Wherein, Vbusmax is the voltage at the first output terminal of the rectifier circuit, and Vacmax is the maximum voltage of the alternating current.

[0168] (2) Rectifier diode current selection:

[0169] Input power: Pint = Pout × working efficiency η (η is taken as 0.485). The system output power Pout can be calculated based on the maximum load.

[0170] Iacmax=Pint / Vacmin (Vacmin is 85V), and 1.5 times is also reserved.

[0171] Among them, Iacmax is the maximum current of AC, Pint is the input power, Pout is the output power, and Vacmin is the minimum voltage of AC.

[0172] In one embodiment of the present application, the utility model provides a kind of household appliance, comprising: the drive control circuit 100 of any one of embodiment.

[0173] The terms "first", "second" in the description and claims of the present application can explicitly or implicitly include one or more of the features. In the literal description of the utility model, unless otherwise specified, the meaning of "multiple" is two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in a "or" relationship.

[0174] In the literal description of the utility model, it can be understood that, except for explicit provisions and limitations, the terms "mounting", "connection", "connection" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected;It can be mechanical structure connection, or electrical connection;It can be that the two are directly connected, or the two are indirectly connected through intermediate medium, or it can be the communication inside two elements.For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to specific circumstances.

[0175] In the claims, description and drawings of the specification of the utility model, the description of the terms "one embodiment", "some embodiments", "specific embodiment" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In the claims, description and drawings of the specification of the utility model, the illustrative expression of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0176] The above is only the preferred embodiment of the utility model, and is not used to limit the utility model. For those skilled in the art, the utility model can have various changes and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the utility model shall be included in the protection scope of the utility model.

Claims

1. A drive control circuit, characterized by comprising: The drive chip is connected with the first grounding point; The micro control unit is connected with the second grounding point; The first optical isolation circuit is located between the first connection end of the micro control unit and the first connection end of the drive chip; The second optical isolation circuit is located between the second connection end of the micro control unit and the second connection end of the drive chip; The temperature sensor is connected with the signal connection end of the micro control unit at the first end, and is connected with the second grounding point at the second end. The drive control circuit further comprises:

2. The drive control circuit according to claim 1, characterized by The first resistance is connected in series between the signal connection end of the micro control unit and the first end of the temperature sensor; The first capacitor is connected with the signal connection end of the micro control unit at the first end, and is connected with the second grounding point at the second end. The drive control circuit further comprises:

3. The drive control circuit according to claim 1, characterized by The live connection end; The zero connection end; The first input end of the rectifier circuit is connected with the live connection end, the second input end of the rectifier circuit is connected with the zero connection end, and the second output end of the rectifier circuit is connected with the first grounding point; The first end of the switching power supply is connected with the first output end of the rectifier circuit, the second end of the switching power supply is connected with the first grounding point, the third end of the switching power supply is connected with the power supply end of the micro control unit, and the fourth end of the switching power supply is connected with the second grounding point; The second resistance is connected in series between the first end of the temperature sensor and the third end of the switching power supply. The rectifier circuit comprises:

4. The drive control circuit according to claim 3, characterized by The anode of the first diode is connected with the live connection end; The first end of the first electrolytic capacitor is connected with the cathode of the first diode and the first end of the switching power supply respectively, and the second end of the first electrolytic capacitor is connected with the zero connection end and the first grounding point respectively. The rectifier circuit comprises:

5. The drive control circuit according to claim 3, wherein The anode of the first diode is connected with the live connection end, and the cathode of the first diode is connected with the first end of the switching power supply; The cathode of the second diode is connected with the zero connection end, and the anode of the second diode is connected with the first grounding point; The first end of the first electrolytic capacitor is connected with the cathode of the first diode, and the second end of the first electrolytic capacitor is connected with the anode of the second diode. The rectifier circuit further comprises:

6. The drive control circuit according to claim 4, characterized by The first filter capacitor is connected with the first electrolytic capacitor in parallel. The switching power supply comprises:

7. The drive control circuit according to claim 3, characterized by The first end of the first primary coil of the transformer is connected with the first output end of the rectifier circuit, the first end of the first secondary coil of the transformer is connected with the first end of the temperature sensor, the second end of the first secondary coil is connected with the second grounding point, and the first end of the second primary coil of the transformer is connected with the power supply end of the drive chip; ​ A first switch tube, a first end of the first switch tube is connected with a second end of the first primary coil, and a second end of the first switch tube is connected with the first grounding point.

8. The drive control circuit according to claim 7, characterized by The switching power supply further comprises: A third diode is located between a first end of the first secondary coil and a first end of the temperature sensor, an anode of the third diode is connected with the first end of the first secondary coil, and a cathode of the third diode is connected with the first end of the temperature sensor.

9. The drive control circuit according to claim 3, characterized by The rectifier circuit comprises: A fourth diode, an anode of the fourth diode is connected with the neutral connection end; A fifth diode, an anode of the fifth diode is connected with the live connection end, and a cathode of the fifth diode is connected with the cathode of the fourth diode and the first end of the switching power supply respectively; A sixth diode, a cathode of the sixth diode is connected with the live connection end; A seventh diode, a cathode of the seventh diode is connected with the neutral connection end, and an anode of the seventh diode is connected with the anode of the sixth diode and the first grounding point respectively; A first electrolytic capacitor, a first end of the first electrolytic capacitor is connected with the cathode of the fifth diode, and a second end of the first electrolytic capacitor is connected with the anode of the seventh diode.

10. The drive control circuit according to claim 3, characterized by The drive control circuit further comprises: A frequency conversion circuit, a first input end of the frequency conversion circuit is connected with a first output end of the rectifier circuit, and a second input end of the frequency conversion circuit is connected with a second output end of the rectifier circuit; A motor, a first input end of the motor is connected with a first output end of the frequency conversion circuit, and a second input end of the motor is connected with a second output end of the frequency conversion circuit.

11. The drive control circuit according to claim 8, characterized by The first optical isolation circuit comprises: A third resistor, a first end of the third resistor is connected with a first connection end of the drive chip; A third capacitor, a first end of the third capacitor is connected with the first end of the third resistor, and a second end of the third capacitor is connected with the first grounding point; A first optocoupler, a first end of the first optocoupler is connected with a second end of the third resistor, a second end of the first optocoupler is connected with a second end of the third capacitor, a third end of the first optocoupler is connected with a first connection end of the micro control unit, and a fourth end of the first optocoupler is connected with a first power supply; A first current-limiting resistor, a first end of the first current-limiting resistor is connected with a first end of the second primary coil of the transformer, and a second end of the first current-limiting resistor is connected with the first end of the first optocoupler; A second current-limiting resistor is connected in series between the third end of the first optocoupler and the first connection end of the micro control unit; The second optical isolation circuit comprises: A fourth resistor, a second end of the fourth resistor is connected with a second connection end of the micro control unit; A fourth capacitor, a first end of the fourth capacitor is connected with the second end of the fourth resistor, and a second end of the fourth capacitor is connected with the second grounding point; a second optocoupler, a first end of the second optocoupler is connected with a first end of the fourth resistor, a second end of the second optocoupler is connected with a second end of the fourth capacitor, a third end of the second optocoupler is connected with the second connection end of the driving chip, and a fourth end of the second optocoupler is connected with a first end of the second primary coil of the transformer; a third current-limiting resistor, a first end of the third current-limiting resistor is connected with the first power supply, and a second end of the third current-limiting resistor is connected with the first end of the second optocoupler; a fourth current-limiting resistor, which is connected in series between the third end of the second optocoupler and the second connection end of the driving chip.

12. A domestic appliance characterized in that, The application further provides a driving control circuit. The driving control circuit according to any one of claims 1 to 11.

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