KR102184000B1 - Charge system and interface apparatus - Google Patents

Abstract

The present invention relates to a charging system and an interface device, comprising a first pin connected to a reference resistance to form a first output voltage in an initial state separated from an external device, and defined according to a voltage change formed on the first pin A charging unit that controls the supply of charging power based on the charged sequence, and operates to supply charging power when a third output voltage is formed on the first pin, and a link node connected to the first pin, and the first Electric drive charging power from the charging unit by lowering the voltage of the link node from the first output voltage to the third output voltage through one or more resistors and one or more switches branched and connected from the link node while the pin and link node are connected And an interface circuit for interfacing with the device.

Description

Charging system and interface device {CHARGE SYSTEM AND INTERFACE APPARATUS}

The present invention relates to a charging system and an interface device, and more particularly, to a charging system and an interface device for charging an electric drive device.

Recently, the development of automobiles that generate power using eco-friendly alternative energy is actively progressing at home and abroad, and automobiles using such eco-friendly alternative energy include pure electric vehicles (EVs), fossil fuels and electric energy. And a hybrid electric vehicle (HEV) and a fuel cell electric vehicle (FCEV). Furthermore, the development of electric vehicles is in the trend of expanding to various means of transportation such as micro electric vehicles for one person, electric scooters, and electric bicycles.

In general, an electric vehicle includes a battery charged with electric power to drive a three-phase motor, a three-phase motor driven by the electric power charged in the battery to drive the electric vehicle, and an inverter for driving the three-phase motor. Are doing. At this time, if the power remaining in the battery falls below a predetermined amount, it is necessary to charge the battery because the three-phase motor can no longer be driven. To this end, the electric vehicle is charged through a charging infrastructure that rectifies a commercial 220V AC voltage from the power grid to charge the battery, and as a charging method through the charging infrastructure, a 5-pin connector or a 7-pin connector as shown in FIG. A method of charging an electric vehicle through a slow charger is widely applied.

In the case of charging an electric vehicle through the charging infrastructure, the voltage of the CP (Control Pilot) pin must be reduced to 6V according to the J1772 international standard, and for this purpose, the voltage of the CP pin must be reduced when designing an OBC (On-Board Charger). Since a microcontroller unit (MCU) that drops to 6V is required, there is a problem of increasing the volume and cost according to the application of the MCU.

In addition, while electric vehicles can be charged using a slow charger having a 5-pin connector or a 7-pin connector, the above-described charging infrastructure is used for micro-electric driving devices that charge through a charging plug such as an electric scooter or an electric bicycle. There are limitations that cannot be used.

Background art of the present invention is disclosed in Korean Patent Application Publication No. 10-2015-0140920 (published on December 17, 2015).

The present invention was invented to solve the above-described problem, and an object according to an aspect of the present invention is to implement a charging sequence without the application of the MCU, which was required to lower the voltage of the CP pin to 6V according to the J1772 international standard. Accordingly, a charging system and an interface device are provided to solve the problem of increasing the volume and cost due to the application of the MCU by charging the electric driving device.

Another object of the present invention is to provide a charging system and an interface device capable of charging a micro electric drive device such as an electric scooter or an electric bicycle by utilizing the existing charging infrastructure.

The charging system according to an aspect of the present invention includes a first pin connected to a reference resistance to form a first output voltage in an initial state separated from an external device, and defined according to a voltage change formed on the first pin. A charging unit that controls the supply of charging power based on a charging sequence and operates to supply the charging power when a third output voltage is formed on the first pin, and a link node connected to the first pin, By lowering the voltage of the link node from the first output voltage to the third output voltage through one or more resistors and one or more switches branched and connected from the link node while the first pin and the link node are connected, And an interface circuit unit for interfacing the charging power from the charging unit to the electric driving device.

In the present invention, the interface circuit unit is connected to a first branch node branching from the link node, and divides the first output voltage with the reference resistor according to the connection of the first pin and the link node. A first resistor for dropping to form a second output voltage at the link node, a first switch for exciting a current flowing through the first resistor to ground, a second connected to a second branch node branching from the link node A resistor, a third resistor connected to a third branch node branching from the link node, to form the third output voltage at the link node by dropping the second output voltage, and a node connected to the second resistor It characterized in that it further comprises a second switch for on-off operation through the voltage supplied from the ground to excite the current flowing through the third resistor to the ground.

In the present invention, the first and second switches are NPN Bipolar Junction Transistor (BJT), the first resistor is connected between the first branch node and the base terminal of the first switch, and the second A resistor is connected between the second branch node and a collector terminal of the first switch, and the third resistor is connected between the third branch node and a collector terminal of the second switch, and the first switch The collector terminal of and the base terminal of the second switch are connected in common, and each emitter terminal of the first and second switches is connected to a ground.

In the present invention, the charging unit is opened and closed according to a user's operation, a second pin connected to the base terminal of the first switch, fourth and fifth resistors connected in series between the second pin and the ground, and In a state, both terminals of the fifth resistor are short-circuited, and in an open state, a charge control switch electrically connecting the fifth resistor to the fourth resistor is further included.

In the present invention, the interface circuit unit, when the charging control switch is opened according to the user's operation, the voltage applied to the base terminal of the first switch is increased so that the first switch is turned on, and the first As the switch is turned on, the voltage applied to the base terminal of the second switch decreases and the second switch is turned off, so that the third resistor floats, and the third resistor floats, the link node The second output voltage is formed at, and thus the supply of charging power from the charging unit is stopped.

An interface device according to an aspect of the present invention includes a link node connected to a CP pin of a charging unit, and includes at least one resistor and at least one switch branched from and connected from the link node when the CP pin and the link node are connected. As an interface circuit unit for interfacing the charging power from the charging unit to an electric driving device by sequentially lowering the voltage of the link node through the charging unit, the charging unit is the CP (Control Pilot) pin to which the reference resistance is connected by applying the J1772 standard protocol. The interface circuit unit, which controls the supply of the charging power based on the charging sequence according to the output voltage formed in the, and accommodates the board on which the interface circuit unit is mounted, and from the charging unit through the operation of the interface circuit unit And a body part for electrically connecting the connector of the charging part and the charging plug of the electric driving device so that charging power of the electric driving device can be supplied to the electric driving device.

In the present invention, the interface circuit unit is connected to a first branch node branching from the link node, and 12V initially formed on the CP pin through voltage distribution with the reference resistance according to the connection of the CP pin and the link node. A first resistor for reducing a voltage to form a 9V voltage at the link node, a first switch for exciting a current flowing through the first resistor to ground, a second connected to a second branch node branching from the link node A resistor, a third resistor connected to a third branch node branching from the link node, to form a 6V output voltage at the link node by dropping the 9V voltage, and a voltage supplied from the node connected to the second resistor It characterized in that it comprises a second switch for on-off operation through the excitation of the current flowing through the third resistor to the ground.

According to an aspect of the present invention, the present invention is essentially to lower the voltage of the CP pin to 6V by implementing a charging sequence according to the J1772 international standard through an interface circuit implemented through a predetermined resistance element and a switch element. By excluding the application of the required MCU, it is possible to solve the problem of increasing the volume and cost of the application of the MCU.

In addition, by electrically connecting the connector of the charger and the charging plug of the electric drive device based on the interface circuit, it is possible to charge micro electric drive devices such as electric scooters or electric bicycles using the existing charging infrastructure. It is possible to improve the ease of charging the device.

1 is an exemplary view showing a 5-pin connector and a 7-pin connector applied to a conventional slow charger.
2 is a block diagram illustrating a charging system according to an embodiment of the present invention.
3 is an exemplary view showing an output voltage formed on a first pin in a charging system according to an embodiment of the present invention.
4 is a circuit diagram showing a circuit configuration of a charging system according to an embodiment of the present invention.
5 is a block diagram illustrating an interface device according to an embodiment of the present invention.
6 is an exemplary diagram showing an example of implementing an interface device according to an embodiment of the present invention.

Hereinafter, embodiments of a charging system and an interface device according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention and may vary according to the intention or custom of users or operators. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

2 is a block diagram illustrating a charging system according to an embodiment of the present invention, and FIG. 3 is an exemplary view showing an output voltage formed on a first pin in a charging system according to an embodiment of the present invention. , Figure 4 is a circuit diagram showing a circuit configuration of a charging system according to an embodiment of the present invention.

Referring to FIG. 2, the charging system 1 according to an embodiment of the present invention may include a charging unit 100 and an interface circuit unit 200.

First, the operation of the charging unit 100 according to the present embodiment will be described as an example of charging the electric vehicle.

The charging unit 100 of this embodiment may mean a slow or fast charger provided in a charging station for charging a battery of an electric driving device such as an electric vehicle, and may be connected to the vehicle through a connector including first to fifth pins. I can. According to the international standard J1772, the first to fifth pins may be CP pins, PP pins, PE pins, L pins, and N pins, respectively. The charging unit 100 may supply charging AC power (AC 220V) to the vehicle's OBC (On-Board Charger) through the fourth and fifth pins, and the third pin may form a ground terminal while connected to the vehicle. I can.

The first pin is provided to apply a charging control pilot (PWM) voltage signal to the vehicle. 3 illustrates an example of a charging control pilot (PWM) voltage signal formed on a first pin. As the output voltage of the first pin, the first to third output voltages indicated below refer to a charge control pilot (PWM) voltage signal, and to aid in understanding of the embodiment, the first to third output voltages are each charge control pilot ( It will be described as referring to a high-level voltage signal among the PWM) voltage signals. That is, according to FIG. 3, the first to third output voltages may mean +12V, +9V, and +6V, respectively, according to international standard J1772.

When the first pin is described in detail, as shown in FIG. 2, a reference resistor R_ref and a PWM voltage control transistor TR_PWM are connected to the first pin, so that the first output voltage ( In other words, a PWM voltage, feq.: 1 kHz) with 0V and the first output voltage as Low-Level and High-Level, respectively, is formed. When the charging unit 100 and the vehicle (electric drive device) are connected, the first pin is connected to a resistor provided on the vehicle side to form a second output voltage from which the first output voltage is lowered. The OBC of the vehicle detects a second output voltage formed on the first pin using an equipped MCU, and causes a third output voltage in which the second output voltage is lowered to be formed on the first pin through a predetermined switch control. The charging unit 100 senses a third output voltage formed on the first pin and supplies charging AC power to the OBC of the vehicle through the fourth and fifth pins. Accordingly, the OBC may charge the battery of the vehicle by converting the charged AC power supplied through the fourth and fifth pins into DC power through the power converter.

In order to control the operation of the above-described charging sequence, an MCU is required in the OBC of the vehicle, and accordingly, the problem of increasing the volume and cost according to the application of the MCU occurs. present. Hereinafter, the present embodiment will be described in detail with reference to FIGS. 2 to 4.

First, the charging unit 100 may include a first pin connected to the reference resistor R_ref to form a first output voltage in an initial state separated from an external device. The charging unit 100 controls the supply of charging power based on a charging sequence defined according to a voltage change formed on the first pin, and may operate to supply charging power when a third output voltage is formed on the first pin. have. According to the international standard J1772, the first pin means the CP pin, the first to third output voltages mean 12V, 9V, 6V, respectively, and the charging sequence is the first to third output voltages on the first pin. This may mean a sequence formed sequentially.

The interface circuit unit 200 includes a link node N_LINK connected to the first pin of the charging unit 100, and is connected by branching from the link node N_LINK while the first pin and the link node N_LINK are connected. By lowering the voltage of the link node N_LINK from the first output voltage to the third output voltage through the above resistors and one or more switches, the charging power from the charging unit 100 may be interfaced to the electric driving device.

That is, in the present embodiment, by forming a third output voltage on the first pin through one or more resistors and one or more switches branched and connected from the link node N_LINK connected to the first pin of the charging unit 100, the MCU A configuration in which a charging sequence for supplying charging power from the charging unit 100 is implemented in a circuit manner is adopted without a separate control operation due to this.

The circuit configuration of the interface circuit unit 200 will be described in detail with reference to FIG. 4.

As illustrated in FIG. 4, the interface circuit unit 200 may include first to third resistors R1, R2, and R3, and first and second switches TR1 and TR2.

The first resistor R1 is connected to the first branch node N1 branching from the link node N_LINK, and through voltage distribution with the reference resistor R_ref according to the connection of the first pin and the link node N_LINK. The first output voltage may be lowered to form a second output voltage at the link node N_LINK. The first switch TR1 may operate to excite the current flowing through the first resistor R1 to the ground. The second resistor R2 is connected to the second branch node N2 branching from the link node N_LINK. The third resistor R3 is connected to the third branch node N3 branching from the link node N_LINK, and may form a third output voltage at the link node N_LINK by lowering the second output voltage. The second switch TR2 may operate on and off through a voltage supplied from a node connected to the second resistor R2 to excite a current flowing through the third resistor R3 to ground.

In this case, the first and second switches TR1 and TR2 may be implemented as an NPN Bipolar Junction Transistor (BJT). Accordingly, the first resistor R1 is connected between the first branch node N1 and the base terminal of the first switch TR1. The second resistor R2 is connected between the second branch node N2 and the collector terminal of the first switch TR1. The third resistor R3 is connected between the third branch node N3 and the collector terminal of the second switch TR2. The collector terminal of the first switch TR1 and the base terminal of the second switch TR2 are connected in common, and the emitter terminals of the first and second switches TR1 and TR2 are connected to the ground.

When the operation of the above-described circuit configuration is described, when the charging unit 100 and the interface circuit unit 200 are connected to each other and the first pin and the link node N_LINK on which the first output voltage is formed are connected, the first pin and the link node A current path leading to (N_LINK), the first resistor R1, the base terminal of the first switch TR1, and the emitter terminal of the first switch TR1 is formed, and the reference resistance R_ref and the first resistance ( A second output voltage from which the first output voltage is dropped is formed at the link node N_LINK by voltage distribution between R1).

At this time, a current path leading to the first pin, the link node N_LINK, the second resistor R2, the base terminal of the second switch TR2, and the emitter terminal of the second switch TR2 is also formed. According to the turn-on operation of the switch TR2, the current flowing to the third resistor R3 (that is, the collector current of the second switch TR2) is excited to the ground (that is, the third resistor R3 is floating from the floating state). It is converted into an active state), and a third output voltage from which the second output voltage is dropped is formed at the link node N_LINK by the third resistor R3.

Accordingly, the charging unit 100 senses a third output voltage (ie, a third output voltage formed on the first pin) formed at the link node N_LINK and supplies charging power through the fourth and fifth pins ( The charging unit 100 senses the third output voltage formed on the first pin through an equipped control unit (MCU), and closes the relay element that regulates the commercial AC power (AC 220V) from the system, thereby Charging power can be supplied through the pin).

On the other hand, a normal slow charger is provided with a predetermined charge control switch that can be operated by the user to stop charging in the charging state for the electric vehicle, and thus the interface circuit unit 200 of this embodiment is also compatible with the operation of the charge control switch. There is a need to be.

As a configuration for this, the charging unit 100 according to the present embodiment may further include a second pin, fourth and fifth resistors R4 and R5, and a charge control switch SW, along with the first pin. The second pin may be connected to the base terminal of the first switch TR1, and may be implemented as a PP pin according to the international standard of J1772. The fourth and fifth resistors R4 and R5 are connected in series between the second pin and the ground. The charging control switch (SW) is opened and closed according to the user's operation, and in the closed state, both terminals of the fifth resistor (R5) are short-circuited, and in the open state, the fifth resistor (R5) is electrically connected to the fourth resistor (R4). Operate to connect.

Accordingly, when the charging control switch SW is opened according to a user's manipulation, the interface circuit unit 200 increases the voltage applied to the base terminal of the first switch TR1 to turn on the first switch TR1. When the first switch TR1 is turned on, the voltage applied to the base terminal of the second switch TR2 decreases, and the second switch TR2 is turned off, so that the third resistor R3 is floating. As the third resistor R3 floats, a second output voltage is formed in the link node N_LINK, so that the supply of charging power from the charging unit 100 may be stopped.

Specifically, when the charge control switch SW is closed, both terminals of the fifth resistor R5 are short-circuited and only the fourth resistor R4 is connected to the first pin, so that the second pin (that is, the first switch ( A low voltage (eg 0.3V) is formed at the base terminal of TR1). Accordingly, the first switch TR1 is maintained in the off state, the second switch TR2 is maintained in the on state, and the third output voltage is maintained at the link node N_LINK by the third resistor R3, thereby charging. The state of power supply is maintained.

When the charging control switch SW is opened according to the user's manipulation, the fifth resistor R5 is electrically connected to the fourth resistor R4, thereby causing the second pin (that is, the base terminal of the first switch TR1). A high voltage (eg, 0.7V or more) is formed in the. Accordingly, the first switch TR1 is turned on, the second switch TR2 is turned off, so that the third resistor R3 is floating, and as the third resistor R3 is floating, the link node N_LINK is As the second output voltage is formed, the supply of charging power from the charging unit 100 is stopped.

Through the above-described configuration, it is possible to implement a charging sequence for supplying charging power from the charging unit 100 as a circuit without a separate control operation by the MCU, while maintaining compatibility with a conventional slow charger.

As described above, there is a limitation in that charging cannot be performed using a slow charger having a 5-pin connector or a 7-pin connector in a micro electric driving device such as an electric scooter or an electric bicycle. By electrically connecting the connector of the slow charger (that is, the charging unit 100) and the charging plug of the electric driving device through the interface circuit unit 200, a configuration capable of charging a micro electric driving device through the slow charger is proposed.

5 is a block diagram illustrating an interface device according to an embodiment of the present invention, and FIG. 6 is an exemplary view illustrating an example of implementing an interface device according to an embodiment of the present invention.

5 and 6, the interface device 2 according to the second embodiment may include an interface circuit unit 200 and a body unit 300.

The charging unit 100 and the interface circuit unit 200 are the same as those of the first embodiment, and will be described below as an embodiment to which the J1772 standard protocol is applied.

First, the charging unit 100 may control the supply of charging power based on a charging sequence according to an output voltage formed on a CP pin to which the reference resistor R_ref is connected by applying the J1772 standard protocol.

The interface circuit unit 200 includes a link node (N_LINK) connected to the CP pin of the charging unit 100, and one or more resistors branched from and connected from the link node (N_LINK) while the CP pin and the link node (N_LINK) are connected. And by sequentially lowering the voltage of the link node (N_LINK) through one or more switches, it is possible to interface the charging power from the charging unit 100 to the electric driving device.

The interface circuit unit 200 is connected to the first branch node N1 branching from the link node N_LINK, as described in the first embodiment, and a reference resistance R_ref according to the connection of the CP pin and the link node N_LINK The first resistor (R1) and the current flowing through the first resistor (R1) to form a 9V voltage at the link node (N_LINK) by dropping the 12V voltage initially formed on the CP pin through voltage distribution of A first switch TR1 for, a second resistor R2 connected to a second branch node N2 branching from the link node N_LINK, and a third branch node N3 branching from the link node N_LINK It is connected to and operates on and off through a voltage supplied from a node connected to the third resistor R3 and a node connected to the second resistor R2 to form a 6V output voltage at the link node N_LINK by dropping the 9V voltage. A second switch TR2 may be included to excite the current flowing through the third resistor R3 to the ground.

The body part 300 may accommodate a board on which the interface circuit part 200 is mounted therein, and the charging part 100 so that the charging power from the charger can be supplied to the electric driving device through the operation of the interface circuit part 200. ) Connector and the charging plug of the electric drive device can be electrically connected.

That is, as shown in FIG. 6, the body part 300 is formed of a synthetic resin material, so that the connector of the charging part 100 is coupled to one end, and the charging plug of the electric driving device may be coupled to the other end. A conductive material (eg, copper) for connecting the L pin and N pin of the connector of the charging unit 100 to the charging plug of the electric driving device, together with the board on which the interface circuit unit 200 is mounted inside the body unit 300 Can be provided.

Through the interface device 2 according to the second embodiment, it is possible to charge a micro electric driving device such as an electric scooter or an electric bicycle using a slow charger having a 5-pin connector or a 7-pin connector.

Meanwhile, the reference resistance (R_ref) described above and the resistance values of the first to fifth resistors (R1, R2, R3, R4, R5) are designed based on the experimental results of the designer within the range in which the above-described operation can be implemented. It can be (e.g. R_ref: 1kΩ, R1: 3.3kΩ, R2: 100kΩ, R3: 1.3kΩ, R4: 150Ω, R5: 330Ω).

As described above, this embodiment implements a charging sequence according to the J1772 international standard through an interface circuit implemented through a predetermined resistance element and a switch element, so that the application of the MCU, which was required to drop the voltage of the CP pin to 6V. By excluding, it is possible to solve the problem of volume and cost increase caused by MCU application.

In addition, by electrically connecting the connector of the charger and the charging plug of the electric drive device based on the interface circuit, it is possible to charge micro electric drive devices such as electric scooters or electric bicycles using the existing charging infrastructure. It is possible to improve the ease of charging the device.

The present invention has been described with reference to the embodiments shown in the drawings, but these are only exemplary, and those of ordinary skill in the art to which the present technology pertains, various modifications and other equivalent embodiments are possible. I will understand. Therefore, the true technical protection scope of the present invention should be determined by the following claims.

1: charging system
2: interface device
100: live part
200: interface circuit unit
300: body part
R_ref: reference resistance
TR_PWM: PWM voltage control transistor
R1, R2, R3, R4, R5: first to fifth resistors
N_LINK: Link node
N1, N2, N3: first to third branch nodes
TR1, TR2: first and second switches
SW: charge control switch

Claims (7)

It includes a first pin connected to a reference resistance to form a first output voltage in an initial state separated from an external device, and supplying charging power based on a charging sequence defined according to a voltage change formed on the first pin. A charging unit that controls and operates to supply the charging power when a third output voltage is formed on the first pin; And
And a link node connected to the first pin, and the voltage of the link node is controlled through at least one resistor and at least one switch branched from and connected from the link node while the first pin and the link node are connected. An interface circuit unit for interfacing charging power from the charging unit to an electric driving device by dropping from one output voltage to the third output voltage;
Including,
The interface circuit unit,
It is connected to a first branch node branching from the link node, and decreases the first output voltage through voltage distribution with the reference resistance according to the connection of the first pin and the link node to output a second output to the link node. A first resistor for forming a voltage;
A first switch configured to excite the current flowing through the first resistor to ground;
A second resistor connected to a second branch node branching from the link node;
A third resistor connected to a third branch node branching from the link node, and configured to form the third output voltage at the link node by dropping the second output voltage; And
A second switch configured to operate on and off through a voltage supplied from a node connected to the second resistor to excite a current flowing through the third resistor to ground;
Charging system, characterized in that it further comprises.
delete The method of claim 1,
The first and second switches are NPN Bipolar Junction Transistor (BJT),
The first resistor is connected between the first branch node and a base terminal of the first switch, and the second resistor is connected between the second branch node and a collector terminal of the first switch The third resistor is connected between the third branch node and the collector terminal of the second switch, the collector terminal of the first switch and the base terminal of the second switch are commonly connected, and the first and second 2 Charging system, characterized in that each emitter terminal of the switch is connected to ground.
The method of claim 3,
The charging unit,
A second pin connected to the base terminal of the first switch;
Fourth and fifth resistors connected in series between the second pin and the ground; And
A charge control switch that opens and closes according to a user's manipulation, shorting both terminals of the fifth resistor in a closed state, and electrically connecting the fifth resistor to the fourth resistor in an open state;
Charging system, characterized in that it further comprises.
The method of claim 4,
When the charging control switch is opened according to the user's manipulation, the interface circuit unit is configured to increase the voltage applied to the base terminal of the first switch to turn on the first switch, and to turn on the first switch. As a result, the voltage applied to the base terminal of the second switch is lowered and the second switch is turned off to cause the third resistor to float, and to the link node as the third resistor floats. Charging system, characterized in that the operation to stop the supply of charging power from the charging unit by the output voltage is formed.
Includes a link node connected to the CP pin of the charging unit, and sequentially lowers the voltage of the link node through at least one resistor and at least one switch branched and connected from the link node while the CP pin and the link node are connected By doing so, as an interface circuit unit for interfacing the charging power from the charging unit to the electric driving device, the charging unit is applied to the J1772 standard protocol and performs a charging sequence according to an output voltage formed on the CP (Control Pilot) pin to which a reference resistance is connected. To control the supply of the charging power based on the interface circuit unit; And
The connector of the charging unit and the charging plug of the electric driving device are electrically connected to accommodate a substrate on which the interface circuit unit is mounted therein, and to supply charging power from the charging unit to the electric driving device through the operation of the interface circuit unit. A body portion for connecting to;
Including,
The interface circuit unit,
It is connected to a first branch node branching from the link node, and a 12V voltage initially formed on the CP pin is dropped through a voltage distribution with the reference resistance according to the connection of the CP pin and the link node to 9V to the link node. A first resistor for forming a voltage;
A first switch configured to excite the current flowing through the first resistor to ground;
A second resistor connected to a second branch node branching from the link node;
A third resistor connected to a third branch node branching from the link node, and configured to drop the 9V voltage to form a 6V output voltage at the link node; And
A second switch configured to operate on and off through a voltage supplied from a node connected to the second resistor to excite a current flowing through the third resistor to ground;
Interface device comprising a. delete

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