Relay type leakage protection device, electrical connection device and electrical appliance

Abstract

The present application discloses a relay type leakage protection device, an electrical connection device and an electrical appliance. The relay type leakage protection device includes: a switch module configured to control the electrical connection on the power supply line; a relay module coupled to the switch module, the relay module includes: a relay configured to control the switching action of the switch module based on the working current; a transistor group including at least one transistor configured to control the working current of the relay; and a pulse width modulation unit configured to provide a pulse width modulation signal with a specified duty cycle to drive the transistor group so that the switch module maintains the electrical connection; a leakage detection module coupled to the power supply line and configured to generate a leakage fault signal based on the detected leakage current signal. When the leakage current signal is a true leakage current signal, the leakage fault signal causes the transistor group to turn off, thereby disconnecting the electrical connection.

Description

Technical Field

[0001] The present application relates to the electrical field, and particularly to a relay type leakage protection device, an electrical connection device, and an electrical appliance. Background Art

[0002] With the continuous improvement of people's awareness of electrical safety, the use of leakage protection devices is becoming more and more widespread, and various electrical appliances will adopt leakage protection devices to connect to the power supply signal. When there is a leakage current signal on the power supply line, the leakage protection device can cut off the power connection. However, the currently used leakage protection devices still have some defects. For example, under long-term operation, the leakage protection device will be burned out, thus generating potential safety hazards, and the power consumption is also relatively high, resulting in a waste of energy. Summary of the Invention

[0003] Based on the above problems, the present application proposes a relay type leakage protection device, which overcomes the above problems by making the relay work under a periodic pulse width modulation signal.

[0004] On the one hand, the present application proposes a relay type leakage protection device, which is characterized in that it includes: a switch module configured to control the power connection on the power supply line; a relay module coupled to the switch module, the relay module including: a relay configured to control the switching action of the switch module based on the working current; a transistor group including at least one transistor configured to control the working current of the relay; and a pulse width modulation unit configured to provide a pulse width modulation signal with a specified duty cycle to drive the transistor group so that the switch module maintains the power connection; a leakage detection module coupled to the power supply line and configured to generate a leakage fault signal based on the detected leakage current signal. When the leakage current signal is a real leakage current signal, the leakage fault signal causes the transistor group to turn off, thereby disconnecting the power connection.

[0005] In one embodiment, the relay type leakage protection device further includes: a first power supply module configured to provide a power supply signal to at least the pulse width modulation unit; the pulse width modulation unit includes: a voltage dividing resistor string including at least two resistors, wherein one end of the voltage dividing resistor string is used to receive the power supply signal, and the other end is coupled to the ground potential to output a voltage dividing signal; a first comparator, whose first input terminal is coupled to a first reference potential, the second input terminal is coupled to the voltage dividing signal, and the output terminal is coupled to the control terminal of the transistor group.

[0006] In one embodiment, the relay type leakage protection device further includes: a reset module, which includes: a reset switch; a first capacitor; a first transistor, whose first anode is coupled to the first capacitor, and the second anode is coupled to the control end of the transistor group. Wherein, when the reset switch is closed, the first transistor pulls down the potential of the control end of the transistor group to make the transistor group cut off, thereby making the switch module disconnect the power connection and discharge the first capacitor. When the reset switch is opened, the reset module provides a reset signal to the control end of the transistor group via the first capacitor, so that the switch module restores the power connection under the control of the relay. Wherein, the voltage value of the reset signal is greater than or equal to the voltage value of the pulse width modulation signal, and / or the duration of the reset signal is greater than or equal to the duration of the pulse width modulation signal within a unit cycle.

[0007] In one embodiment, the relay type leakage protection device further includes: a self-check module, which is configured to provide a periodic simulated leakage current signal to the leakage detection module. Wherein, the self-check module includes: a second comparator, whose first input terminal is coupled to a self-check period timing circuit, and the second input terminal is coupled to a second reference potential; a second transistor, whose first pole is coupled to the first input terminal of the second comparator, the second pole is coupled to the ground potential, and the control pole is used to receive the leakage fault signal; a third transistor, whose first pole is coupled to the leakage detection module, the second pole is coupled to the ground potential, and the control pole is coupled to the output terminal of the second comparator to generate the simulated leakage current signal based on the output signal of the second comparator; a second power supply module, which is configured to provide at least a power supply signal to the self-check module.

[0008] In one embodiment, the first reference potential and the second reference potential are generated by the same or different reference potential circuits. For example, when the first reference potential and the second reference potential are equal, they can be coupled to the first comparator and the second comparator by the same reference potential circuit to provide reference potential to the two comparators; similarly, they can also be provided to the two comparators by two independent reference potential circuits respectively. In another embodiment, the first reference potential and the second reference potential can also be different. Similarly, they can also be provided by one or two independent reference potential circuits.

[0009] In one embodiment, the leakage detection module includes: a fourth transistor, whose first pole is coupled to the output terminal of the first comparator, the second pole is coupled to the ground potential, and the control pole receives the leakage fault signal via a first resistor and is coupled to the ground potential via a second capacitor.

[0010] In one embodiment, the relay module includes: a fusible element, which is connected in series to the relay working circuit. When the effective working current in the relay circuit is abnormal, that is, when the working current in the relay is greater than or equal to a first threshold and the duration is greater than or equal to a second threshold, the fusible element melts to disconnect the power connection.

[0011] In one embodiment, it includes a fuse, an enameled wire, or other fuse devices of the same type.

[0012] In one embodiment, the transistor group includes: a fifth transistor, whose first pole is connected in series and coupled to the relay, and the control pole is coupled to the output terminal of the pulse width modulation unit via a second resistor; a sixth transistor, whose first pole is connected in series and coupled to the second pole of the fifth transistor, the control pole is coupled to the output terminal of the pulse width modulation unit via a third resistor, and the second pole is coupled to the ground potential.

[0013] In one embodiment, at least one of the second to sixth transistors is selected from: a field effect transistor; a thyristor; and a bipolar transistor; and other controllable switching elements.

[0014] On the other hand, this application also discloses an electrical connection device, including: a housing; a leakage protection device, which is accommodated in the housing and includes: a switch module, which is configured to control the power connection on the power supply line; a relay module, which is coupled to the switch module, and the relay module includes: a relay, which is configured to control the switching action of the switch module based on the working current; a transistor group, which includes at least one transistor, which is configured to control the relay to provide the working current; and a pulse width modulation unit, which is configured to provide a pulse width modulation signal with a specified duty cycle to drive the transistor group, so that the switch module maintains the power connection; a leakage detection module, which is coupled to the power supply line and is configured to generate a leakage fault signal based on the detected leakage current signal. When the leakage current signal is a real leakage current signal, the leakage fault signal causes the transistor group to turn off, thereby disconnecting the power connection.

[0015] In one embodiment, the electrical connection device further includes: a first power module, which is configured to rectify the AC voltage signal on the power supply line to generate a first power signal and convert the first power signal into a DC second power signal; the pulse width modulation unit includes: a voltage dividing resistor string, which includes at least two resistors, wherein one end of the voltage dividing resistor string is used to receive the first power signal, and the other end is coupled to the ground potential to output a voltage dividing signal; a first comparator, whose first input terminal is coupled to a first reference potential, the second input terminal is coupled to the voltage dividing signal, and the output terminal is coupled to the control terminal of the transistor group.

[0016] In one embodiment, the electrical connection device further includes a reset module, which includes: a reset switch; a first capacitor; a first transistor, whose first anode is coupled to the first capacitor, and whose second anode is coupled to the control terminal of the transistor group. When the reset switch is closed, the first transistor pulls down the potential of the control terminal of the transistor group so that the transistor group is turned off, thereby causing the switch module to disconnect the power connection and discharge the first capacitor. When the reset switch is opened, the reset module provides a reset signal to the control terminal of the transistor group via the first capacitor, so that the switch module restores the power connection under the control of the relay. Wherein, the voltage value of the reset signal is greater than or equal to the voltage value of the pulse width modulation signal, and / or the duration of the reset signal is greater than or equal to the duration of the pulse width modulation signal within a unit period.

[0017] In one embodiment, the electrical connection device further includes: a self-check module configured to provide a periodic simulated leakage current signal to the leakage detection module. The self-check module includes: a second comparator, whose first input terminal is coupled to a timing circuit, and whose second input terminal is coupled to a second reference potential; a second transistor, whose first pole is coupled to the first input terminal of the second comparator, whose second pole is coupled to the ground potential, and whose control pole is used to receive the leakage fault signal; a third transistor, whose first pole is coupled to the leakage detection module, whose second pole is coupled to the ground potential, and whose control pole is coupled to the output terminal of the second comparator to generate the simulated leakage current signal based on the output signal of the second comparator; a second power supply module configured to provide at least a power supply signal to the self-check module.

[0018] On the other hand, the present application also discloses an electrical appliance, including: a load electrical appliance; an electrical connection device coupled between the power supply line and the load electrical appliance to supply power to the load electrical appliance, wherein the electrical connection device includes the relay-type leakage protection device as described in any one of the foregoing.

[0019] By implementing the technical solutions of the present application, the energization time of the relay can be reduced, thereby reducing the heat generated by the relay and related components, and reducing the power consumption of the product. Description of the Drawings

[0020] The embodiments are illustrated and explained with reference to the accompanying drawings. These drawings are used to illustrate the basic principles and thus only show the aspects necessary for understanding the basic principles. These drawings are not to scale. In the drawings, the same reference numerals represent similar features. Additionally, the connection lines between each block in the architecture diagram indicate an electrical or magnetic coupling between two blocks, and the absence of a connection line between two blocks does not mean that the two blocks are not coupled.

[0021] Figure 1 The architecture diagram of the relay-type leakage protection device according to an embodiment of the present application;

[0022] Figure 2 The schematic diagram of the relay-type leakage protection device according to an embodiment of the present application. Detailed implementation manners

[0023] In the following detailed description of the preferred embodiments, reference will be made to the accompanying drawings that form a part of the present application. The accompanying drawings illustrate, by way of example, specific embodiments that can be implemented in the present application. The example embodiments are not intended to exhaust all embodiments according to the present application. It can be understood that other embodiments can be utilized without departing from the scope of the present application, and structural or logical modifications can also be made. Therefore, the following detailed description is not restrictive, and the scope of the present application is defined by the appended claims.

[0024] First, the terms involved in the present application are elaborated. A transistor can refer to a transistor of any structure, such as a field-effect transistor (FET), a bipolar junction transistor (BJT), or a thyristor. When the transistor is a field-effect transistor, its control electrode refers to the gate of the field-effect transistor, the first electrode can be the drain or source of the field-effect transistor, and the corresponding second electrode can be the source or drain of the field-effect transistor; when the transistor is a bipolar junction transistor, its control electrode refers to the base of the bipolar junction transistor, the first electrode can be the collector or emitter of the bipolar junction transistor, and the corresponding second electrode can be the emitter or collector of the bipolar junction transistor; when the transistor is a thyristor, its control electrode refers to the control electrode G of the thyristor, the first electrode is the anode, and the second electrode is the cathode. It can be understood that transistors with control electrodes are not limited to the above types, and can also be other controllable switching elements.

[0025] In addition, the present application also relates to a transistor with dual input terminals (i.e., Figure 2 Q3 in), which has two anodes. The simulated leakage current signal is a periodic pulse signal generated by the self-check module, and the real leakage current signal is an aperiodic signal generated by the power supply line. When the real leakage current signal occurs, the leakage protection device needs to disconnect the power connection.

[0026] The inventor found through practice that the relay and the electronic components connected in series with it in the traditional relay-type leakage protection device are always in a working state, which is likely to cause damage to the components. For example, when the transistor controlling the relay is short-circuited, the relay is continuously powered on, resulting in an increase in heat and also a high power consumption.

[0027] In view of the above problems, the present application aims to provide a relay-type leakage protection device, which reduces the energization time of the relay, reduces the generated heat, and reduces the power consumption of the product by operating the relay under a periodic pulse width modulation signal.

[0028] Figure 1 It is a schematic diagram of the architecture of the leakage protection device according to an embodiment of the present application.

[0029] As Figure 1 shown, the leakage protection device 100 includes a power supply module 1, a leakage detection module 2, a self-check module 3, a switch module 4, a relay module 5, and a reset module 6.

[0030] The switch module 4 is coupled between the input terminal IN and the output terminal OUT to control the electrical connection therebetween. The power supply module 1 is used to obtain power from the power supply line and supply power to the leakage detection module 2, the self-check module 3, the relay module 5, and the reset module 6. The leakage detection module 2 is coupled to the power supply line to generate a leakage fault signal based on the detected leakage current signal. When the leakage current signal is a real leakage current signal, the leakage fault signal causes the relay module 5 to stop working, and further causes the switch module 4 to disconnect the electrical connection.

[0031] The relay module 5 includes a relay unit 51 (which includes a relay and a transistor group) and a pulse width modulation unit 52. Among them, the relay is configured to control the switching action of the switch module 4 based on the working current, and the transistor group is configured to control the working current of the relay; and the pulse width modulation unit 52 is configured to provide a driving signal (i.e., a PWM signal) with a specified duty cycle to the transistor group to maintain the electrical connection of the switch module. Therefore, when there is no real leakage current signal, the working current in the relay will exist discontinuously under the influence of the driving signal, thereby reducing the effective value of the working current, reducing the heat generated by the relay circuit, and reducing the power consumption of the product.

[0032] Figure 2 It is a circuit schematic diagram of the leakage protection device according to an embodiment of the present application.

[0033] The leakage protection device includes a power supply module 1, a leakage detection module 2, a self-check module 3, a switch module 4, a relay module 5, and a reset module 6. The operation between each module will be described below.

[0034] The power supply module 1 includes a first sub-power supply 11 and a second sub-power supply 12. Among them, the first sub-power supply 11 is used to supply power to the leakage detection module 2 and the relay module 5, and the second sub-power supply 12 is used to supply power to the self-check module 3. Specifically, the first sub-power supply 11 includes a rectifier bridge DB, a diode D1, a capacitor C6 and a resistor R6. Among them, the rectifier bridge DB takes power from the power supply line and outputs a first power signal, and converts the first power signal through the resistor R6 and the capacitor C6 to provide a DC second power signal to the processor U1 in the leakage detection module 2. Similarly, the second sub-power supply 12 takes power from the power supply line and is coupled to the comparator U2A in the self-check module 3 through the resistor R10 to supply power to the comparator U2A.

[0035] The self-check module 3 is used to perform periodic functional checks on the leakage detection module 2. The self-check module 3 includes a self-check cycle timing circuit and a self-check signal circuit for generating an analog leakage current signal. See Figure 2 , the self-check cycle timing circuit includes a resistor R16 and a capacitor C10 connected in series, which are used to generate the interval of the self-check pulse signal; the self-check signal circuit includes electronic components such as a transistor Q2, a comparator U2A, a capacitor C14, a resistor R18, and resistors R7 and R20 respectively coupled to the transistor Q2. The self-check module 3 periodically applies an analog leakage current signal with a duration of a predetermined time to the detection loop CT1.

[0036] The leakage detection module 2 includes a detection loop CT1, a detection loop CT2 passing through the power supply line, and a leakage processing unit coupled to the two detection loops. Among them, the leakage processing unit includes a processor U1 and its associated coupled electronic components, such as capacitors C2, C3, etc. When there is a current imbalance longer than a predetermined time in the power supply line passing through the detection loop CT1 (i.e., there is a real leakage current signal), a corresponding voltage signal will be generated on the detection loop CT1. The processor U1 generates a leakage fault signal by detecting the voltage change generated on the detection loop CT1, so that the transistor Q4 conducts and the transistor Q1 cuts off, thereby causing the relay RELAY to lose power and the switch module 4 to disconnect.

[0037] The relay module 5 includes a relay unit 51 and a pulse width modulation unit 52. Among them, the relay unit 51 includes a relay RELAY and a transistor Q1 connected in series. The output of the pulse width modulation unit 52 is coupled to the control electrode of the transistor Q1 to provide a driving signal (i.e., a pulse width modulation signal) with a specified duty cycle to the transistor Q1. This pulse width modulation signal is configured to make the relay RELAY conduct and disconnect at a specified frequency without affecting the operation of the switch module 4, thereby reducing the power of the relay RELAY. In other words, when the relay RELAY conducts and disconnects at this specified frequency, the switch module 4 maintains the electrical connection. It can be understood that this specified frequency can be adjusted according to the application scenario. For example, the on-time of the relay RELAY can be adjusted by adjusting the value of the reference voltage Vref1 or the voltage dividing resistor string.

[0038] Specifically, the pulse width modulation unit 52 includes: a voltage dividing resistor string, which includes at least two resistors, such as resistors R8 and R14. One end of the voltage dividing resistor string is used to receive a first power signal (i.e., a periodically changing signal output by the rectifier bridge DB), and the other end is coupled to the ground potential to output a voltage dividing signal at the node between the resistors R8 and R14; the positive input terminal of the comparator U2B is coupled to the reference potential Vref1, the negative input terminal is coupled to the voltage dividing signal, and the output terminal is coupled to the control electrode of the transistor Q1 via the resistor R11.

[0039] If the transistor Q1 is disconnected for a long enough time (greater than or equal to the first time threshold), that is, the time when the relay RELAY coil remains de-energized is greater than or equal to the first time threshold, the relay RELAY cannot keep the switch module 4 in the conducting state, thereby disconnecting the electrical connection between the input terminal and the output terminal.

[0040] In another embodiment, the leakage protection device may further include a fusing element P1. When the working current in the relay is abnormal, the fusing element P1 will fuse and disconnect the electrical connection. Specifically, the fusing element P1 is connected in series at any position in the working circuit of the relay RELAY. This working circuit refers to DB - D1 - Relay - Q1 - ground potential. For example, in addition to Figure 2 the position shown in, the fusing element P1 can also be connected in series between the rectifier bridge DB and the diode D1. When the transistor Q1 is in a short - circuit state, the voltage generated by the processor U2B cannot effectively drive the transistor Q1. The relay RELAY coil and the fusing element P1 will be in a conducting state for a long time. Therefore, the current flowing through the fusing element P1 increases and the heat rises, causing the fusing element P1 to fuse, cutting off the current of the relay RELAY coil, and then disconnecting the electrical connection between the input terminal and the output terminal. It can be understood that the fusing element P1 can be any fusing (i.e., disconnecting) device, such as a fuse or the enameled wire of a relay.

[0041] In another embodiment, the relay unit 51 includes a transistor group, which includes a plurality of transistors connected in series in sequence. For example, when the transistor group includes transistors Q1 and Q1', the first pole of transistor Q1 is coupled to one end of the coil, the second pole is coupled to the first pole of transistor Q1', and the second pole of transistor Q1' is coupled to the ground potential. Among them, the control poles of the two transistors are both coupled to the output terminal of the processor U2B. In one embodiment, the control poles of the two transistors are respectively coupled to the output terminal of the processor U2B through resistors. In other words, the control terminals of the transistor group are respectively coupled to the control poles of each transistor via resistors and / or diodes.

[0042] The reset module 6 includes transistor Q3, reset switch RESET, capacitors C8, C11, resistor R21, and diode D5. When the reset switch RESET is closed, transistor Q3 conducts, and at the same time, pulls down the potentials of nodes A and B, causing transistor Q1 to turn off. After RESET is disconnected, the first sub-power supply 11 charges capacitor C8 and provides a reset signal to transistor Q to cause transistor Q1 to conduct. It can be understood that this reset signal is a temporary signal, and the voltage value of this voltage signal is greater than the output voltage of the comparator U2B, so that the relay is attracted. In one embodiment, the duration of this voltage signal is also greater than the width of the pulse width modulation signal output by U2B to further ensure reliable attraction of the relay.

[0043] In other words, when the reset switch RESET is closed, transistor Q3 pulls down the control pole potential of transistor Q1 to cause transistor Q1 to turn off, thereby causing the switch module to disconnect the power connection and discharge capacitor C8; when the reset switch RESET is disconnected, the DC signal provided by the first sub-power module 11 provides a reset signal to the control pole of transistor Q1 via capacitor C8, so that the switch module 4 restores the power connection under the control of the relay module 5. In one embodiment, the voltage value of the reset signal is greater than or equal to the voltage value of the pulse width modulation signal, and / or the duration of the reset signal is greater than or equal to the duration of the pulse width modulation signal within a unit period.

[0044] Therefore, the pulse width modulation signal output by the comparator U2B can cause transistor Q1 to conduct or turn off periodically while maintaining the switch module 4 from disconnecting the power supply connection. After the reset switch is closed, transistor Q1 turns off and the switch module 4 disconnects the power supply connection. Therefore, in order to enable the relay RELAY to re-adsorb and close the already disconnected switch, a higher operating current and / or conduction time need to be provided to the relay RELAY.

[0045] The working principle of this embodiment is as follows:

[0046] When powered, the capacitor C10 is charged through the resistor R16 in the self-check unit 4. When the potential of the capacitor C10 is charged to be higher than the threshold voltage Vref2, the output signal of the comparator U2A flips and outputs a high potential, causing the transistor Q2 to conduct. In one embodiment, the threshold voltage adopted by the self-check unit 4 can be equal to the reference voltage in the pulse width modulation unit 52, i.e., Vref1 = Vref2. It can be seen from Figure 2 that the reference potential Vref2 is generated by the reference potential circuit R17 - R22. It can be understood that Vref1 can also be generated by this reference potential circuit R17 - R22, or can be generated by other independent reference potential circuits.

[0047] After the transistor Q2 conducts, a current flows through the resistor R7, that is, an analog leakage current signal is provided to the detection coil CT1. The processor U1 collects the voltage change of the capacitor C2 and will output a leakage fault signal. After the transistor Q5 gets this leakage fault signal, the transistor Q5 conducts, while the transistor Q4 does not conduct due to the limitation of the resistor R19 and the capacitor C13. After the transistor Q5 conducts, it will discharge the capacitor C10, thereby causing the potential on C10 to rapidly decrease, and further causing the comparator U2A to turn off or output a low level, then the transistor Q2 cuts off, and stops providing the analog leakage current to the leakage detection module 3. Since the analog leakage current disappears, at this time, the processor U1 also stops outputting the leakage fault signal, the control pole voltage of the transistor Q5 drops, and then it cuts off. The second sub-power supply module 12 starts to charge the capacitor C10 again, thus realizing the next cycle of self-check. It can be understood that the analog leakage current is a periodic signal.

[0048] It can be understood that when there is a real leakage current signal on the power supply line, the duration of this real leakage current signal is longer than the duration of the analog leakage current signal generated by the self-check module 3. When a real leakage current signal appears, the detection coil CT1 detects this leakage current signal, and the processor U1 outputs a leakage fault signal. Similarly, the transistor Q5 conducts before the transistor Q4. If both the analog leakage current signal and the real leakage current signal exist at this time, the prior conduction of the transistor Q5 can remove the analog leakage current signal to avoid the influence of the analog leakage current signal on the real leakage current signal. Since the real leakage current signal still exists, therefore, the leakage fault signal also exists correspondingly, causing the transistor Q4 to conduct, and then pulling down the potential of the node B, causing the transistor Q1 to cut off, and the relay RELAY loses power, and the switch module 4 disconnects.

[0049] When a self-check fault (i.e., a fault affecting the self-check process) occurs, the leakage protection device in the present application can disconnect the power supply connection. Take the short circuit of the capacitor C2 or the detection coil CT1 as an example.

[0050] As described above, during the self-check cycle, the second sub-power supply 12 charges the capacitor C10 through the resistors R10 and R16. When the positive potential of the comparator U2A is higher than Vref2, the processor U2A outputs a high potential, causing the transistor Q2 to conduct. However, due to the short circuit of the capacitor C1 or the detection coil CT1, the detection coil CT1 cannot detect the analog leakage current signal. Therefore, the processor U1 cannot generate a leakage fault signal for this analog leakage current signal, and thus the transistor Q5 cannot conduct. At this time, the potential of the capacitor C10 is higher than the negative pole of the comparator U2A, and the comparator U2A continuously outputs a high potential (i.e., the self-check fault signal), and then charges the capacitor C14 through the resistor R20. When the diode D7 conducts, it triggers the transistor Q4 to conduct; when the transistor Q4 conducts, it pulls down the potential of the node A, causing the transistor Q1 not to conduct, so that the relay RELAY loses power and the switch module 4 disconnects.

[0051] The present application also proposes an electrical connection device, which includes a leakage protection device and a housing. Among them, the leakage protection device includes: a switch module configured to control the electrical connection on the power supply line; a relay module coupled to the switch module, and the relay module includes: a relay configured to control the switching action of the switch module based on the working current; a transistor group including at least one transistor configured to control the working current of the relay; and a pulse width modulation unit configured to provide a pulse width modulation signal with a specified duty cycle to the transistor group to drive the transistor group so that the switch module maintains the electrical connection; a leakage detection module coupled to the power supply line, configured to generate a leakage fault signal based on the detected leakage current signal. When the leakage current signal is a real leakage current signal, the leakage fault signal causes the transistor group to cut off, and then the electrical connection is disconnected.

[0052] It can be understood that the leakage protection device in this electrical connection device may include some or all of the technical features in the embodiments described in Figure 1 , Figure 2 . The present application also proposes an electrical appliance, which includes: a load electrical appliance and the electrical connection device as described above.

[0053] By adopting the technical solution of the present application, the energization time of the relay can be reduced, thereby reducing the heat generated by the relay and related components, and reducing the power consumption of the product.

[0054] Therefore, although the present application is described with reference to specific examples, and these specific examples are only illustrative and do not limit the present application, it is obvious to those of ordinary skill in the art that changes, additions or deletions can be made to the disclosed embodiments without departing from the spirit and protection scope of the present application.

Claims

1. A relay type leakage protection device, characterized in that, Comprising: A switch module configured to control the power connection on the power supply line; A relay module coupled to the switch module, the relay module comprising: A relay configured to control the switching action of the switch module based on the operating current; A transistor group including at least one transistor configured to control the operating current of the relay; and A pulse width modulation unit configured to provide a pulse width modulation signal with a specified duty cycle to the transistor group to drive the transistor group so that the switch module maintains the power connection; A leakage detection module coupled to the power supply line, configured to generate a leakage fault signal based on the detected leakage current signal. When the leakage current signal is a real leakage current signal, the leakage fault signal causes the transistor group to turn off, thereby causing the power connection to be disconnected; and A reset module, the reset module comprising: A reset switch; A first capacitor; and A first transistor, whose first anode is coupled to the first capacitor and the second anode is coupled to the control terminal of the transistor group, wherein When the reset switch is closed, the first transistor pulls down the potential of the control terminal of the transistor group to cause the transistor group to turn off, thereby causing the switch module to disconnect the power connection and discharge the first capacitor, When the reset switch is opened, the reset module provides a reset signal to the control terminal of the transistor group via the first capacitor so that the switch module restores the power connection under the control of the relay, wherein the voltage value of the reset signal is greater than or equal to the voltage value of the pulse width modulation signal, and / or the duration of the reset signal is greater than or equal to the duration of the pulse width modulation signal within a unit period.

2. The relay type leakage protection device according to claim 1, characterized in that, Further comprising: A first power supply module configured to provide at least a power supply signal to the pulse width modulation unit; The pulse width modulation unit comprises: A voltage dividing resistor string including at least two resistors, wherein one end of the voltage dividing resistor string is used to receive the power supply signal and the other end is coupled to the ground potential to output a voltage dividing signal; A first comparator, whose first input terminal is coupled to a first reference potential, the second input terminal is coupled to the voltage dividing signal, and the output terminal is coupled to the control terminal of the transistor group.

3. The relay type leakage protection device according to claim 1, characterized in that, Further comprising: A self-check module configured to provide a periodic analog leakage current signal to the leakage detection module, wherein the self-check module comprises: A second comparator, whose first input terminal is coupled to a self-check cycle timing circuit and the second input terminal is coupled to a second reference potential; A second transistor, whose first pole is coupled to the first input terminal of the second comparator, the second pole is coupled to the ground potential, and the control pole is used to receive the leakage fault signal; A third transistor, whose first pole is coupled to the leakage detection module, the second pole is coupled to the ground potential, and the control pole is coupled to the output terminal of the second comparator to generate the analog leakage current signal based on the output signal of the second comparator; A second power supply module configured to provide at least a power supply signal to the self-check module.

4. The relay type leakage protection device according to claim 3, characterized in that, The leakage detection module comprises: A fourth transistor, having a first pole coupled to the control terminal of the transistor group, a second pole coupled to the ground potential, and a control pole receiving the leakage fault signal and / or the self-check fault signal via a first resistor and coupled to the ground potential via a second capacitor.

5. The relay type leakage protection device according to claim 1, characterized in that, Comprising: A fusible element, which is connected in series in the working circuit of the relay and is configured to fuse to disconnect the power connection when the working current in the relay is greater than or equal to a first threshold and the duration is greater than or equal to a second threshold.

6. The relay type leakage protection device according to claim 5, characterized in that, The fusible element is a fuse or an enameled wire.

7. The relay type leakage protection device according to claim 4, characterized in that, The transistor group includes: A fifth transistor, having a first pole connected in series to the relay and a control pole coupled to the output terminal of the pulse width modulation unit via a second resistor; A sixth transistor, having a first pole connected in series to the second pole of the fifth transistor, a control pole coupled to the output terminal of the pulse width modulation unit via a third resistor, and a second pole coupled to the ground potential.

8. The relay type leakage protection device according to claim 7, characterized in that, At least one of the second to sixth transistors is selected from: A field effect transistor; A thyristor; and A bipolar transistor.

9. An electrical connection device, characterized in that, Comprising: A housing; A leakage protection device, which is accommodated in the housing and includes: A switch module, which is configured to control the power connection on the power supply line; A relay module, which is coupled to the switch module, and the relay module includes: A relay, which is configured to control the switching action of the switch module based on the working current; A transistor group, which includes at least one transistor and is configured to control the working current of the relay; and A pulse width modulation unit, which is configured to provide a pulse width modulation signal with a specified duty cycle to drive the transistor group so that the switch module maintains the power connection; A leakage detection module, which is coupled to the power supply line and is configured to generate a leakage fault signal based on the detected leakage current signal. When the leakage current signal is a real leakage current signal, the leakage fault signal causes the transistor group to turn off, thereby causing the power connection to be disconnected; and A reset module, and the reset module includes: A reset switch; A first capacitor; A first transistor, having a first anode coupled to the first capacitor and a second anode coupled to the control terminal of the transistor group, wherein When the reset switch is closed, the first transistor pulls down the potential of the control terminal of the transistor group to cause the transistor group to turn off, thereby causing the switch module to disconnect the power connection and discharge the first capacitor, When the reset switch is open, the reset module provides a reset signal to the control terminal of the transistor group via the first capacitor so that the switch module restores the power connection under the control of the relay, wherein the voltage value of the reset signal is greater than or equal to the voltage value of the pulse width modulation signal, and / or the duration of the reset signal is greater than or equal to the duration of the pulse width modulation signal in a unit cycle.

10. The electrical connection device according to claim 9, characterized in that, Further comprising: A first power supply module, which is configured to provide a power signal to at least the pulse width modulation unit; The pulse width modulation unit includes: A voltage-dividing resistor string, which includes at least two resistors. One end of the voltage-dividing resistor string is used to receive the power signal, and the other end is coupled to the ground potential to output a voltage-dividing signal; A first comparator, whose first input terminal is coupled to a first reference potential, the second input terminal is coupled to the voltage-dividing signal, and the output terminal is coupled to the control terminal of the transistor group.

11. The electrical connection device according to claim 9, wherein, It further includes: A self-checking module, which is configured to provide a periodic analog leakage current signal to the leakage detection module. The self-checking module includes: A second comparator, whose first input terminal is coupled to a timing circuit, and the second input terminal is coupled to a second reference potential; A second transistor, whose first pole is coupled to the first input terminal of the second comparator, the second pole is coupled to the ground potential, and the control pole is used to receive the leakage fault signal; A third transistor, whose first pole is coupled to the leakage detection module, the second pole is coupled to the ground potential, and the control pole is coupled to the output terminal of the second comparator to generate the analog leakage current signal based on the output signal of the second comparator; A second power supply module, which is configured to supply at least a power signal to the self-checking module.

12. An electrical appliance, characterized in that, It includes: A load electrical appliance; An electrical connection device, which is coupled between the power supply line and the load electrical appliance to supply power to the load electrical appliance. The electrical connection device includes the relay-type leakage protection device according to any one of claims 1 to 8.

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