Input DC power reverse connection compatible circuit, power supply circuit and household appliances

Abstract

This invention provides a DC power input reverse connection compatible circuit, a power supply circuit, and a household appliance. The DC power input reverse connection compatible circuit includes a first diode, a second diode, a third diode, and a control switch. The anode of the first diode is electrically connected to the positive input terminal, and the cathode of the first diode is electrically connected to the positive output terminal. The cathode of the second diode is electrically connected to the positive output terminal, and the anode of the second diode is electrically connected to the negative output terminal. The anode of the third diode is electrically connected to the negative output terminal, and the cathode of the third diode is electrically connected to the negative input terminal. The first terminal of the control switch is electrically connected to the negative input terminal, and the second terminal of the control switch is electrically connected to the positive output terminal. A reverse connection detection circuit is used to acquire the reverse connection signal between the positive and negative input terminals, and controls the control switch to turn on or off based on the reverse connection signal. This invention is compatible with both forward and reverse DC power connections and improves circuit safety during reverse connections.

Description

Technical Field

[0001] This utility model relates to the field of power supply circuit technology, specifically to an input DC power supply reverse connection compatible circuit, a power supply circuit using the input DC power supply reverse connection compatible circuit, and a household appliance using the power supply circuit. Background Technology

[0002] Currently, some frequency converters, servo drives and other equipment require DC power supply. When wiring the DC power input, there are often cases where the positive and negative terminals are reversed due to various reasons. If power is applied directly at this time, it may cause the downstream load circuit to malfunction or even burn out the downstream circuit components, which is highly dangerous and causes great losses.

[0003] In existing DC power supply reverse connection circuits, see Figure 1 To prevent circuit damage caused by reverse polarity connection, a diode D0 is connected in series with the positive terminal of the power supply. The anode of diode D0 is electrically connected to the positive terminal of the power supply, and the cathode of diode D0 is electrically connected to the positive output terminal. The positive output terminal of diode D0 is electrically connected to the positive terminal of the load R0, and the negative terminal of the load R0 is electrically connected to the negative terminal of the power supply. When the power supply is connected in the correct orientation, diode D0 conducts in the forward direction, thus providing power normally. For reverse polarity connection, see [link to relevant documentation]. Figure 2 The diode D0 is reverse-biased and cuts off the circuit, thus preventing it from reaching the next stage of the circuit. However, in this design, the circuit cannot function when the power supply is reversed, requiring cumbersome rewiring.

[0004] In a current circuit supporting DC power supply reversibility, a first current blocker is connected between the positive power supply interface and the positive output interface, and a second current blocker is connected between the negative power supply interface and the positive output interface. The line from the positive power supply interface to the first current blocker is sequentially connected to the gate of a first MOSFET and the source of a second MOSFET. The line from the negative power supply interface to the second current blocker is sequentially connected to the source of the first MOSFET and the gate of the second MOSFET. The negative power supply interface is connected to the drain of both the first and second MOSFETs. When the power supply to the electronic device is reversed, the second current blocker conducts in the forward direction, the first current blocker blocks the current, the second MOSFET conducts, and the first MOSFET is cut off. The current flows through the negative power supply interface, the second current blocker, the positive output interface, the load device, the negative output interface, the second MOSFET, and the positive power supply interface. Reversing the power supply changes the voltage potential across the terminals of the appliance, thus achieving the polarity reversal function of the current.

[0005] However, in this scheme, the gate of the MOSFET is connected to the positive power supply interface and the positive output interface only through a resistor. When the voltage is too high, the MOSFET is easily burned out, causing the circuit to malfunction.

[0006] Therefore, a more optimized power supply circuit that is compatible with both positive and negative polarity needs to be considered. Utility Model Content

[0007] The primary objective of this invention is to provide an input DC power supply reverse connection compatible circuit that is compatible with both forward and reverse connections of DC power supply and can improve circuit safety when both connections are reversed.

[0008] The second objective of this invention is to provide an air conditioner that is compatible with both positive and negative DC power supply connections and can improve circuit safety when connected in both directions.

[0009] The third objective of this invention is to provide a computer-readable storage medium that is compatible with both positive and negative DC power supply connections and can improve circuit safety when connected in both directions.

[0010] To achieve the aforementioned first objective, the DC power input reverse connection compatible circuit provided by this utility model includes a positive input terminal, a negative input terminal, a positive output terminal, a negative output terminal, a reverse connection compatible circuit, and a reverse connection detection circuit. The reverse connection compatible circuit includes a first diode, a second diode, a third diode, and a control switch. The positive terminal of the first diode is electrically connected to the positive input terminal, and the negative terminal of the first diode is electrically connected to the positive output terminal. The negative terminal of the second diode is electrically connected to the positive output terminal, and the positive terminal of the second diode is electrically connected to the negative output terminal. The positive terminal of the third diode is electrically connected to the negative output terminal, and the negative terminal of the third diode is electrically connected to the negative input terminal. The first terminal of the control switch is electrically connected to the negative input terminal, and the second terminal of the control switch is electrically connected to the positive output terminal. The reverse connection detection circuit is used to acquire the reverse connection signal between the positive input terminal and the negative input terminal, and control the control switch to turn on or off according to the reverse connection signal.

[0011] As can be seen from the above scheme, in the DC power input reverse connection compatible circuit of this utility model, the first diode, the second diode, the third diode, and the control switch form a forward and reverse connection compatible circuit. Combined with the forward and reverse connection detection circuit, when the positive and negative terminals of the DC power supply are incorrectly connected, the forward and reverse connection detection circuit can identify the reverse connection signal. Through the switching on and off of the control switch and the unidirectional conductivity of the diodes, it ensures that the output terminal can still provide a voltage of the correct polarity to the load, preventing damage to the load due to reverse power connection. The switching on and off of the diodes and the control switch are both fast-acting. Combined with the real-time signal recognition of the forward and reverse connection detection circuit, the state switch can be completed instantly upon reverse power connection with almost no delay, effectively preventing the load from experiencing reverse voltage at the moment of reverse connection. At the same time, the simple circuit structure reduces potential failure points and improves the reliability and safety of long-term operation.

[0012] In a further embodiment, when the positive or negative signal is a positive signal, the control switch is closed; when the positive or negative signal is a negative signal, the control switch is open.

[0013] Therefore, the switching of the positive and negative working circuits can be achieved by turning the control switch on or off according to the positive and negative connection signals.

[0014] In a further embodiment, the control switch includes a switching transistor, with its first terminal electrically connected to the negative input terminal and its second terminal electrically connected to the positive output terminal. A positive / reverse connection detection circuit sends a control signal to the control terminal of the switching transistor.

[0015] As can be seen, the control switch uses a switching transistor with an extremely short on or off time (usually in the nanosecond to microsecond range). Combined with the signal output of the positive and negative connection detection circuit, it can complete the state switching instantly when the power supply is reversed, thus improving the response speed.

[0016] In a further design, the switching transistor is a low-level on switching transistor.

[0017] In a further embodiment, the positive / reverse connection detection circuit includes a first resistor, a second resistor, and a third resistor. The first end of the first resistor is electrically connected to the negative input terminal, the second end of the first resistor is electrically connected to the first end of the second resistor, the second end of the second resistor is electrically connected to the first end of the third resistor, the second end of the second resistor is also electrically connected to the positive input terminal, the second end of the third resistor is electrically connected to the second electrode of the switching transistor, and the control electrode of the switching transistor is electrically connected to the second end of the first resistor.

[0018] Therefore, the positive / reverse connection detection circuit can divide the input voltage when the circuit is connected in the positive or reverse direction by setting the first resistor and the second resistor, so as to provide voltage to the control electrode of the switching transistor. At the same time, the third resistor pulls up or down the cathode of the switching transistor to ensure that it has a level reference point to meet the conduction conditions of the switching transistor.

[0019] In a further embodiment, the positive / reverse connection detection circuit includes a comparator circuit. The first input terminal of the comparator circuit is electrically connected to the positive input terminal, the second input terminal of the comparator circuit is electrically connected to the negative input terminal, and the output terminal of the comparator circuit is electrically connected to the control electrode of the switching transistor.

[0020] Therefore, it can be seen that the positive and negative connection detection circuit uses a comparator circuit to detect the positive and negative connection states of the positive and negative input terminals. It can more accurately detect voltage changes near the voltage threshold, making it suitable for situations with small input voltages and improving control accuracy.

[0021] In a further embodiment, the switching transistor is a low-level conducting switching transistor; the non-inverting input terminal of the comparator circuit is electrically connected to the positive input terminal, the inverting input terminal of the comparator circuit is electrically connected to the negative input terminal, and the output terminal of the comparator circuit is electrically connected to the control electrode of the switching transistor.

[0022] Therefore, the comparator circuit can be connected to the positive and negative input terminals according to the conduction conditions of the switching transistor, thereby satisfying the control requirements of the switching transistor.

[0023] To achieve the second objective of this utility model, this utility model provides a power supply circuit, including an input DC power supply reverse connection compatible circuit, wherein the input DC power supply reverse connection compatible circuit adopts the above-mentioned input DC power supply reverse connection compatible circuit.

[0024] To achieve the third objective of this utility model, the household appliance provided by this utility model is equipped with a power supply circuit, which adopts the power supply circuit described above. Attached Figure Description

[0025] Figure 1 This is the circuit diagram of an existing DC power supply reverse connection circuit when it is connected in the forward direction.

[0026] Figure 2 This is the circuit diagram of an existing DC power supply reverse connection circuit when reversed.

[0027] Figure 3 This is a circuit diagram of the first embodiment of the DC power input reverse connection compatible circuit of this utility model.

[0028] Figure 4 This is a circuit diagram of the first embodiment of the DC power input reverse connection compatible circuit of this utility model when it is connected in the forward connection.

[0029] Figure 5 This is a circuit diagram of the first embodiment of the DC power input reverse connection compatible circuit of this utility model when reverse connection is applied.

[0030] Figure 6 This is a circuit diagram of the second embodiment of the DC power input reverse connection compatible circuit of this utility model.

[0031] Figure 7 This is a circuit diagram of the second embodiment of the DC power input reverse connection compatible circuit of this utility model when it is connected in the forward connection.

[0032] Figure 8 This is a circuit diagram of the second embodiment of the DC power input reverse connection compatible circuit of this utility model when reverse connection is applied.

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0034] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present invention or its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention thorough and complete, and to fully express the scope of the present invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0035] The terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] In this invention, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not exist between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may not be directly connected to the other devices but may have an intermediary device.

[0037] All terms used in this invention (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0038] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0039] First embodiment of the DC power supply reverse connection compatible circuit:

[0040] like Figure 3 As shown, in this embodiment, the DC power supply reverse connection compatibility circuit includes a positive input terminal 1, a negative input terminal 2, a positive output terminal 3, a negative output terminal 4, a reverse connection compatibility circuit 5, and a reverse connection detection circuit 6.

[0041] The reversible circuit 5 includes a first diode D1, a second diode D2, a third diode D3, and a control switch. The anode of the first diode D1 is electrically connected to the positive input terminal 1, and the cathode of the first diode D1 is electrically connected to the positive output terminal 3. The cathode of the second diode D2 is electrically connected to the positive output terminal 3, and the anode of the second diode D2 is electrically connected to the negative output terminal 4. The anode of the third diode D3 is electrically connected to the negative output terminal 4, and the cathode of the third diode D3 is electrically connected to the negative input terminal 2. The first terminal of the control switch is electrically connected to the negative input terminal 2, and the second terminal of the control switch is electrically connected to the positive output terminal 3.

[0042] The positive / reverse connection detection circuit 6 is used to acquire the positive / reverse connection signal between the positive input terminal 1 and the negative input terminal 2, and controls the control switch to be turned on or off according to the positive / reverse connection signal. In this embodiment, when the positive / reverse connection signal is a positive signal, the control switch is off. When the positive / reverse connection signal is a reverse signal, the control switch is on.

[0043] The control switch can be a relay switch or a switching transistor. In this embodiment, the control switch includes a switching transistor Q1. The first terminal of the switching transistor Q1 is electrically connected to the negative input terminal 2, and the second terminal of the switching transistor Q1 is electrically connected to the positive output terminal 3. The positive / reverse connection detection circuit 6 sends a control signal to the control terminal of the switching transistor Q1. The control switch uses a switching transistor Q1, which has extremely short conduction and cutoff times (typically in the nanosecond to microsecond range). Combined with the signal output of the positive / reverse connection detection circuit 6, it can complete the state switching instantly when the power supply is reversed, improving the response speed. The switching transistor Q1 can be one of a MOSFET, thyristor, or transistor. In this embodiment, the switching transistor Q1 is a low-level conduction switching transistor.

[0044] In this embodiment, the positive / reverse connection detection circuit 6 includes a first resistor R1, a second resistor R2, and a third resistor R3. The first end of the first resistor R1 is electrically connected to the negative input terminal 2, the second end of the first resistor R1 is electrically connected to the first end of the second resistor R2, the second end of the second resistor R2 is electrically connected to the first end of the third resistor R3, the second end of the second resistor R2 is also electrically connected to the positive input terminal 1, and the second end of the third resistor R3 is electrically connected to the second electrode of the switching transistor Q1. The control electrode of the switching transistor Q1 is electrically connected to the second end of the first resistor R1. By setting the first resistor R1 and the second resistor R2, the positive / reverse connection detection circuit 6 can divide the input voltage when the circuit is connected in the positive direction and then in the reverse direction to provide a voltage to the control electrode of the switching transistor Q1. At the same time, the third resistor R3 pulls up or down the cathode of the switching transistor Q1 to ensure that it has a level reference point to meet the conduction condition of the switching transistor Q1.

[0045] In this embodiment, when the DC power supply S1 is connected to the input DC power supply reverse connection compatibility circuit, the switch Q1 is in the off state. After the voltage is divided by the first resistor R1 and the second resistor R2, the intermediate point voltage is connected to the control electrode of the switch Q1. The input DC power supply S1 is determined to be reversed based on the voltage between the control electrode and the second electrode of the switch Q1.

[0046] If the DC power supply S1 is connected in reverse to the input DC power supply and the compatible circuit is connected in the correct direction, such as Figure 4 As shown, at this time, the potential of the second terminal of the switching transistor Q1 is pulled up by the third resistor R3, approaching the positive voltage of the DC power supply S1. However, the potential obtained by the voltage divider through the first resistor R1 and the second resistor R2 is lower than that of the positive terminal of the DC power supply S1. Therefore, the control terminal of the switching transistor Q1 is at a low level relative to the second terminal, and the switching transistor Q1 will turn off. At this time, the current loop is: positive terminal of DC power supply S1 - first diode D1 - load R - third diode D3 - negative terminal of DC power supply S1. Of course, a voltage divider loop also exists in this process, such as... Figure 4 The part indicated by the dashed arrow.

[0047] If the DC power supply S1 is reverse-connected to the input DC power supply, the compatibility circuit is reverse-connected, such as Figure 5 As shown, at this time, the potential of the second terminal of the switching transistor Q1 is pulled down by the third resistor R3, approaching the negative voltage of the DC power supply S1. However, the potential obtained by the voltage divider through the first resistor R1 and the second resistor R2 is much higher than the negative voltage of the DC power supply S1. Therefore, the control terminal of the switching transistor Q1 is at a high level relative to the second terminal, and the switching transistor Q1 will conduct. At this time, the current loop is: positive terminal of DC power supply S1 - switching transistor Q1 - load R - second diode D2 - negative terminal of DC power supply S1. Of course, a voltage divider loop also exists in this process, such as... Figure 5 The part indicated by the dashed arrow.

[0048] Second embodiment of the DC power supply reverse connection compatible circuit:

[0049] The difference between the input DC power supply reverse connection compatible circuit of this embodiment and the first embodiment lies only in the specific circuit structure of the positive and negative connection detection circuit 6. The following description focuses on the differences, and the reference numerals are the same as those of the first embodiment.

[0050] See Figure 6 In this embodiment, the positive / reverse connection detection circuit 6 includes a comparator circuit U1. The first input terminal of the comparator circuit U1 is electrically connected to the positive input terminal 1, the second input terminal of the comparator circuit U1 is electrically connected to the negative input terminal 2, and the output terminal of the comparator circuit U1 is electrically connected to the control electrode of the switching transistor Q1. The positive / reverse connection detection circuit 6 uses the comparator circuit U1 to detect the positive / reverse connection status of the positive input terminal 1 and the negative input terminal 2, which can more accurately detect voltage changes near the voltage threshold, making it suitable for situations with small input voltages and improving control accuracy.

[0051] The comparator circuit U1 can be connected to the positive input terminal 1 and the negative input terminal 2 according to the conduction condition of the switching transistor Q1, thereby satisfying the control requirements of the switching transistor Q1. In this embodiment, the switching transistor Q1 is a low-level conducting switching transistor Q1. The non-inverting input terminal of the comparator circuit U1 is electrically connected to the positive input terminal 1, the inverting input terminal of the comparator circuit U1 is electrically connected to the negative input terminal 2, and the output terminal of the comparator circuit U1 is electrically connected to the control electrode of the switching transistor Q1.

[0052] In this embodiment, when the DC power supply S1 is connected to the DC power supply reverse connection compatibility circuit, the switching transistor Q1 is in the off state. The comparator circuit U1 detects the voltage of the positive input terminal 1 and the negative input terminal 2 to determine whether the connection is reversed. The output terminal of the comparator circuit U1 sends a control signal to the control terminal of the switching transistor Q1.

[0053] If the DC power supply S1 is connected in reverse to the input DC power supply and the compatible circuit is connected in the correct direction, such as Figure 7 As shown, at this time, the non-inverting input terminal of comparator circuit U1 is input with a high level, the inverting input terminal of comparator circuit U1 is input with a low level, and the output terminal of comparator circuit U1 outputs a high level to the control electrode of switching transistor Q1. At this time, switching transistor Q1 will be turned off. At this time, the current loop is: positive terminal of DC power supply S1 - first diode D1 - load R - third diode D3 - negative terminal of DC power supply S1.

[0054] If the DC power supply S1 is reverse-connected to the input DC power supply, the compatibility circuit is reverse-connected, such as Figure 8 As shown, at this time, the non-inverting input terminal of comparator circuit U1 is input with a low level, the inverting input terminal of comparator circuit U1 is input with a high level, and the output terminal of comparator circuit U1 outputs a low level to the control electrode of switching transistor Q1, so switching transistor Q1 will conduct. At this time, the current loop is: positive terminal of DC power supply S1 - switching transistor Q1 - load R - second diode D2 - negative terminal of DC power supply S1.

[0055] Power supply circuit example:

[0056] In this embodiment, the power supply circuit includes an input DC power supply reverse connection compatibility circuit, which adopts the input DC power supply reverse connection compatibility circuit of the above embodiment.

[0057] Example of household appliances:

[0058] In this embodiment, the household appliance is equipped with a power supply circuit, which adopts the power supply circuit of the above embodiment.

[0059] Household appliances include air conditioners, washing machines, televisions, fans, range hoods, air purifiers, humidifiers, dehumidifiers, and other household appliances.

[0060] As described above, in the DC power input reverse connection compatible circuit of this utility model, the first diode D1, the second diode D2, the third diode D3, and the control switch form the forward and reverse connection compatible circuit 5. Combined with the forward and reverse connection detection circuit, when the positive and negative terminals of the DC power supply are incorrectly connected, the forward and reverse connection detection circuit 6 can identify the reverse connection signal. Through the switching on and off of the control switch and the unidirectional conductivity of the diodes, it ensures that the output terminal can still provide the correct polarity voltage to the load, preventing damage to the load due to reverse power connection. The switching on and off of the diodes and the control switch are both fast-acting. Combined with the real-time signal recognition of the forward and reverse connection detection circuit 6, the state switch can be completed instantly upon reverse power connection with almost no delay, effectively preventing the load from experiencing reverse voltage at the moment of reverse connection. At the same time, the simple circuit structure reduces potential failure points and improves the reliability and safety of long-term operation.

[0061] It should be noted that the above are only preferred embodiments of the present utility model, but the design concept of the utility model is not limited thereto. Any non-substantial modifications made to the present utility model using this concept shall also fall within the protection scope of the present utility model.

Claims

1. A DC power input reverse connection compatible circuit, characterized in that, It includes a positive input terminal, a negative input terminal, a positive output terminal, a negative output terminal, a positive / reverse connection compatibility circuit, and a positive / reverse connection detection circuit; The reversible circuit includes a first diode, a second diode, a third diode, and a control switch. The anode of the first diode is electrically connected to the positive input terminal, and the cathode of the first diode is electrically connected to the positive output terminal. The cathode of the second diode is electrically connected to the positive output terminal, and the anode of the second diode is electrically connected to the negative output terminal. The anode of the third diode is electrically connected to the negative output terminal, and the cathode of the third diode is electrically connected to the negative input terminal. The first terminal of the control switch is electrically connected to the negative input terminal, and the second terminal of the control switch is electrically connected to the positive output terminal. The positive / reverse connection detection circuit is used to obtain the positive / reverse connection signal between the positive input terminal and the negative input terminal, and to control the control switch to be turned on or off according to the positive / reverse connection signal.

2. The input DC power supply reverse connection compatible circuit according to claim 1, characterized in that: When the positive / negative connection signal is a positive connection signal, the control switch is closed; When the positive and negative connection signals are reversed, the control switch is turned on.

3. The input DC power supply reverse connection compatible circuit according to claim 1 or 2, characterized in that: The control switch includes a switching transistor, the first terminal of which is electrically connected to the negative input terminal, and the second terminal of which is electrically connected to the positive output terminal. The positive / reverse connection detection circuit sends a control signal to the control terminal of the switching transistor.

4. The input DC power supply reverse connection compatible circuit according to claim 3, characterized in that: The switching transistor is a low-level conducting switching transistor.

5. The input DC power supply reverse connection compatible circuit according to claim 4, characterized in that: The positive / reverse connection detection circuit includes a first resistor, a second resistor, and a third resistor. The first end of the first resistor is electrically connected to the negative input terminal. The second end of the first resistor is electrically connected to the first end of the second resistor. The second end of the second resistor is electrically connected to the first end of the third resistor. The second end of the second resistor is also electrically connected to the positive input terminal. The second end of the third resistor is electrically connected to the second electrode of the switching transistor. The control electrode of the switching transistor is electrically connected to the second end of the first resistor.

6. The input DC power supply reverse connection compatible circuit according to claim 3, characterized in that: The positive / reverse connection detection circuit includes a comparator circuit. The first input terminal of the comparator circuit is electrically connected to the positive input terminal, the second input terminal of the comparator circuit is electrically connected to the negative input terminal, and the output terminal of the comparator circuit is electrically connected to the control electrode of the switching transistor.

7. The input DC power supply reverse connection compatible circuit according to claim 6, characterized in that: The switching transistor is a low-level conducting switching transistor; The non-inverting input terminal of the comparator circuit is electrically connected to the positive input terminal, the inverting input terminal of the comparator circuit is electrically connected to the negative input terminal, and the output terminal of the comparator circuit is electrically connected to the control electrode of the switching transistor.

8. A power supply circuit, comprising an input DC power supply reverse compatibility circuit, characterized in that: The input DC power supply reverse connection compatibility circuit adopts the input DC power supply reverse connection compatibility circuit as described in any one of claims 1 to 7.

9. A household appliance, comprising a power supply circuit, characterized in that: The power supply circuit adopts the power supply circuit described in claim 8.

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