Charging interface protection circuit, circuit board and terminal equipment

Abstract

The present application discloses a charging interface protection circuit, a circuit board and a terminal device, and relates to the field of charging protection technology. The charging interface protection circuit includes: a charging interface, a reverse high-voltage resistant chip, a capacitor filter circuit, an RC suppression circuit and a surge suppression circuit; the charging interface is connected to the output end of the reverse high-voltage resistant chip, and the input end of the reverse high-voltage resistant chip is used to connect to the built-in power supply end of the terminal device. The charging interface and the reverse high-voltage resistant chip are connected to the ground wire through the capacitor filter circuit, the RC suppression circuit and the surge suppression circuit. The capacitor filter circuit, the RC suppression circuit and the surge suppression circuit are arranged in parallel with each other, the capacitor filter circuit is close to the position of the charging interface, the surge suppression circuit is close to the position of the output end of the reverse high-voltage resistant chip, and the RC suppression circuit is located between the capacitor filter circuit and the surge suppression circuit. The present application can protect the built-in power supply end from being burned out during charging and extend the service life of the circuit board.

Description

Technical Field

[0001] The present application relates to the field of charging protection technology, and in particular to a charging interface protection circuit, a circuit board and a terminal device. Background Art

[0002] Terminal devices, especially laptops, often have interfaces that can be connected to external devices. The interface can be used to power the external device and read data information from the external device. The power supply to the external device is achieved by connecting a circuit to the built-in power supply terminal of the terminal device. The interface can also be connected to a charging adapter to charge the built-in battery of the terminal device. However, if the charging adapter has a different protocol from that of the terminal device or has no protocol, the built-in power supply terminal will be directly burned out through the above circuit, thereby causing damage to the circuit board. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a charging interface protection circuit, a circuit board and a terminal device, which can protect the built-in power supply terminal from being burned during charging and extend the service life of the circuit board.

[0004] In a first aspect, the present application provides a charging interface protection circuit, comprising:

[0005] A charging interface, a reverse high-voltage resistant chip, a capacitor filter circuit, an RC suppression circuit and a surge suppression circuit; the charging interface is electrically connected to the output end of the reverse high-voltage resistant chip, the input end of the reverse high-voltage resistant chip is used to connect to the built-in power supply end of the terminal device, the charging interface and the reverse high-voltage resistant chip are connected to a ground wire through the capacitor filter circuit, the RC suppression circuit and the surge suppression circuit, the capacitor filter circuit, the RC suppression circuit and the surge suppression circuit are arranged in parallel with each other, the capacitor filter circuit is close to the charging interface, the surge suppression circuit is close to the output end of the reverse high-voltage resistant chip, and the RC suppression circuit is located between the capacitor filter circuit and the surge suppression circuit.

[0006] The charging interface protection circuit according to the first aspect embodiment of the present application has at least the following beneficial effects: the charging interface protection circuit is a circuit for supplying power to the external device by the built-in power supply terminal of the terminal device when the external device is inserted into the charging interface. At the same time, the charging interface can also charge the built-in battery through another charging conversion circuit. When the charging adapter is inserted into the charging interface, part of the current in the charging adapter charges the built-in battery from the charging conversion circuit. At the same time, part of the current will flow to the charging interface protection circuit of the present application, and the current of the charging adapter cannot flow into the output terminal of the reverse high-voltage resistant chip. The reverse high-voltage resistant chip is provided to prevent the current from flowing from the circuit to the built-in power supply terminal to avoid false adaptation. The device directly acts on the built-in power supply terminal, causing the built-in power supply terminal to burn out. At the same time, in order to protect the reverse high-voltage resistant chip, before the current flows into the output terminal of the reverse high-voltage resistant chip, it first passes through the capacitor filter circuit to filter the voltage of the charging adapter, and then absorbs part of the surge voltage at the moment the charging adapter is inserted through the RC suppression circuit. Finally, the surge voltage is further absorbed through the surge suppression circuit, and at the same time it can withstand high surge power. That is, the capacitor filter circuit, RC suppression circuit and surge suppression circuit play a role in protecting the reverse high-voltage resistant chip, and the reverse high-voltage resistant chip plays a role in protecting the built-in power supply terminal of the terminal device, which can protect the built-in power supply terminal from being burned out during charging and extend the service life of the circuit board.

[0007] According to some embodiments of the first aspect of the present application, the capacitor filtering circuit includes a first capacitor and a second capacitor, one end of the first capacitor and the second capacitor are respectively connected to the charging interface and the output end of the reverse high-voltage resistant chip, and the other end of the first capacitor and the second capacitor are connected to the ground wire.

[0008] According to some embodiments of the first aspect of the present application, the RC suppression circuit includes a first resistor, a third capacitor and a fourth capacitor, one end of the first resistor is connected between the charging interface and the output end of the reverse high-voltage resistant chip, one end of the third capacitor and the fourth capacitor are connected to the other end of the first resistor, and the other ends of the third capacitor and the fourth capacitor are connected to the ground wire.

[0009] According to some embodiments of the first aspect of the present application, the surge suppression circuit includes a unidirectional TVS tube, the cathode of which is connected between the charging interface and the output end of the reverse high-voltage resistant chip, and the anode of which is connected to the ground wire.

[0010] According to some embodiments of the first aspect of the present application, a voltage stabilizing protection circuit is further included, and a ground line is connected between the input end of the reverse high-voltage resistant chip and the built-in power supply end of the terminal device through the voltage stabilizing protection circuit.

[0011] According to some embodiments of the first aspect of the present application, the voltage regulator protection circuit includes a voltage regulator diode, the cathode of the voltage regulator diode is connected between the input end of the reverse high-voltage resistant chip and the built-in power supply end of the terminal device, and the anode of the voltage regulator diode is connected to the ground wire.

[0012] According to some embodiments of the first aspect of the present application, a fifth capacitor and a sixth capacitor are also included, one end of the fifth capacitor and the sixth capacitor is connected to the input end of the reverse high-voltage resistant chip and the voltage regulator diode, and the other end of the fifth capacitor and the sixth capacitor is connected to the ground line.

[0013] According to some embodiments of the first aspect of the present application, a second resistor is also included, and the reverse high-voltage resistant chip is also provided with a current limiting setting pin and a switch input pin, the current limiting setting pin is connected to the ground wire through the second resistor, the current limiting setting pin is used to set the overcurrent threshold, and the switch input pin is used to send a work suspension signal.

[0014] In a second aspect, the present application also provides a circuit board, comprising a charging interface protection circuit as described in any embodiment of the first aspect.

[0015] The circuit board according to the embodiment of the second aspect of the present application has at least the following beneficial effects: a charging interface protection circuit in the circuit board, the charging interface protection circuit is a circuit for powering the external device by the built-in power supply end of the terminal device when the external device is inserted into the charging interface, and at the same time, the charging interface can also charge the built-in power supply end through another charging conversion circuit, and when the charging adapter is inserted into the charging interface, part of the current in the charging adapter charges the built-in power supply end from the charging conversion circuit, and at the same time, part of the current will flow to the charging interface protection circuit of the present application, and the current of the charging adapter cannot flow into the output end of the reverse high-voltage resistant chip, and the reverse high-voltage resistant chip is provided to prevent the current from flowing from the circuit to the built-in power supply end. , so as to prevent the fake adapter from directly acting on the built-in power supply terminal and causing the built-in power supply terminal to burn out. At the same time, in order to protect the reverse high-voltage resistant chip, before the current flows into the output end of the reverse high-voltage resistant chip, it first passes through the capacitor filter circuit to filter the voltage of the charging adapter, and then absorbs part of the surge voltage at the moment of the charging adapter being inserted through the RC suppression circuit. Finally, the surge voltage is further absorbed through the surge suppression circuit, and at the same time, it can withstand high surge power. That is, the capacitor filter circuit, RC suppression circuit and surge suppression circuit play a role in protecting the reverse high-voltage resistant chip, and the reverse high-voltage resistant chip plays a role in protecting the built-in power supply terminal of the terminal device, which can protect the built-in power supply terminal from being burned out during charging and extend the service life of the circuit board.

[0016] In a third aspect, the present application also provides a terminal device, comprising the circuit board as described in the embodiment of the second aspect.

[0017] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0019] Figure 1 A circuit block diagram of a charging interface protection circuit of some embodiments of the first aspect of the present application;

[0020] Figure 2 A circuit diagram of a charging interface protection circuit according to some embodiments of the first aspect of the present application;

[0021] Figure 3 This is an internal circuit diagram of a reverse high-voltage resistant chip according to some embodiments of the first aspect of the present application.

[0022] The figures are as follows:

[0023] Reverse high voltage resistant chip 110 ; charging interface 120 ; capacitor filter circuit 130 ; RC suppression circuit 140 ; ​​surge suppression circuit 150 ; voltage stabilization protection circuit 160 ; built-in power supply terminal 170 . DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0025] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0026] In the description of this application, if there is a description of first or second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0027] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0028] First, refer to Figure 1 The present application provides a charging interface protection circuit, which is applied to a terminal device, including: a charging interface 120, a reverse high voltage resistant chip 110, a capacitor filter circuit 130, an RC suppression circuit 140 and a surge suppression circuit 150; the charging interface 120 is electrically connected to the output end of the reverse high voltage resistant chip 110, and the input end of the reverse high voltage resistant chip 110 is used to connect to the built-in power supply end 170 of the terminal device, and the charging interface 120 and the reverse high voltage resistant chip 110 are connected to the ground wire through the capacitor filter circuit 130, the RC suppression circuit 140 and the surge suppression circuit 150, and the capacitor filter circuit 130, the RC suppression circuit 140 and the surge suppression circuit 150 are arranged in parallel with each other, the capacitor filter circuit 130 is close to the position of the charging interface 120, the surge suppression circuit 150 is close to the position of the output end of the reverse high voltage resistant chip 110, and the RC suppression circuit 140 is located between the capacitor filter circuit 130 and the surge suppression circuit 150, and at the same time, the RC suppression circuit 140 is also close to one side of the reverse high voltage resistant chip 110.

[0029] The charging interface protection circuit is a circuit for supplying power to the external device through the built-in power supply terminal 170 of the terminal device when the external device is inserted into the charging interface 120. At the same time, the charging interface 120 can also charge the built-in battery through another charging conversion circuit. When the charging adapter is inserted into the charging interface 120, part of the current in the charging adapter charges the built-in power supply terminal 170 from the charging conversion circuit. At the same time, part of the current will flow to the charging interface protection circuit of the present application, and the current of the charging adapter cannot flow into the output terminal of the reverse high-voltage resistant chip 110. The reverse high-voltage resistant chip 110 is provided to prevent the current from flowing from the circuit to the built-in power supply terminal 170, so as to prevent the fake adapter from directly acting on the built-in power supply terminal 170, causing the built-in power supply terminal 170 to Burned, at the same time, in order to protect the reverse high-voltage resistant chip 110, before the current flows into the output end of the reverse high-voltage resistant chip 110, it first passes through the capacitor filter circuit 130 to filter the voltage of the charging adapter, and then absorbs a part of the surge voltage at the moment of the charging adapter being inserted through the RC suppression circuit 140, and finally further absorbs the surge voltage through the surge suppression circuit 150, and can withstand high surge power at the same time, that is, the capacitor filter circuit 130, the RC suppression circuit 140 and the surge suppression circuit 150 play a role in protecting the reverse high-voltage resistant chip 110, and the reverse high-voltage resistant chip 110 plays a role in protecting the built-in power supply terminal 170 of the terminal device, which can protect the built-in power supply terminal 170 from being burned out during charging, thereby extending the service life of the circuit board.

[0030] It should be noted that the above-mentioned built-in power supply terminal 170 can be directly connected to the built-in battery, or the built-in battery can be connected to the built-in power supply terminal 170 after voltage reduction and voltage regulation, which is not limited in this application. In this application, the voltage of the built-in power supply terminal 170 is 5V. Figure 2 In the figure, +VBUS_TYPEC indicates the charging interface 120, and +5V indicates the built-in power supply.

[0031] It should be noted that the above-mentioned fake adapter represents a charging adapter that does not conform to the charging protocol of the corresponding terminal device or has no charging protocol. At the same time, the charging interface 120 can be a Micro USB interface, a Type-C interface, a lighting interface, etc., which is not limited in this application.

[0032] Specifically, the reverse high-voltage resistant chip 110 can allow current to flow in from the input end and flow out from the output end, and within the reverse cut-off voltage threshold, current is not allowed to flow in from the output end and flow out from the output end. In another case, when the charging interface 120 is connected to an external device, the external device can be a USB flash drive, etc. The current of the built-in power supply terminal 170 flows in from the input end of the reverse high-voltage resistant chip 110 and flows out from the output end, so that the external device is powered on, thereby powering the external device and reading the data information of the external device. Furthermore, when the charging interface 120 is connected to a charging adapter, the built-in power supply terminal 170 will not work, and the current of the charging adapter cannot pass through the reverse high-voltage resistant chip 110.

[0033] It should be noted that the terminal devices mentioned above can be mobile terminal devices or non-mobile terminal devices. Mobile terminal devices can be mobile phones, tablet computers, laptop computers, PDAs, vehicle-mounted terminal devices, wearable devices, ultra-mobile personal computers, netbooks, personal digital assistants, CPE, UFI (wireless hotspot devices), etc.; non-mobile terminal devices can be personal computers, televisions, ATMs or self-service machines, etc.; the embodiments of the present invention are not specifically limited.

[0034] Reference Figure 2 It can be understood that the capacitor filter circuit 130 includes a first capacitor C1 and a second capacitor C2, one end of the first capacitor C1 and the second capacitor C2 are respectively connected to the charging interface 120 and the output end of the reverse high-voltage resistant chip 110, and the other end of the first capacitor C1 and the second capacitor C2 are connected to the ground wire. Through the cooperation of the first capacitor C1 and the second capacitor C2, the voltage output by the charging adapter is filtered, and the output voltage of the charging adapter is more stable. In one embodiment of the present application, the capacity of the first capacitor C1 and the second capacitor C2 are both 10μF, and the rated voltage is 25V.

[0035] Continue to refer to Figure 2 It can be understood that the RC suppression circuit 140 includes a first resistor R1, a third capacitor C3 and a fourth capacitor C4, one end of the first resistor R1 is connected between the charging interface 120 and the output end of the reverse high-voltage resistant chip 110, one end of the third capacitor C3 and the fourth capacitor C4 is connected to the other end of the first resistor R1, and the other ends of the third capacitor C3 and the fourth capacitor C4 are connected to the ground wire. After the dummy adapter is inserted into the charging interface 120, the RC circuit can absorb part of the surge voltage. In one embodiment of the present application, the first resistor R1 is 1Ω, the third capacitor C3 and the fourth capacitor C4 are both 10μF, and the rated voltage is 25V.

[0036] Continue to refer to Figure 2It can be understood that the surge suppression circuit 150 includes a unidirectional TVS tube D1, the cathode of the unidirectional TVS tube D1 is connected between the charging interface 120 and the output end of the reverse high-voltage resistant chip 110, and the anode of the unidirectional TVS tube D1 is connected to the ground wire. The unidirectional TVS tube D1 has the properties of low reverse voltage and high peak pulse current. In one embodiment, the model of the unidirectional TVS tube D1 is SEP2011P1, which is not limited in this application.

[0037] Reference Figure 1 It can be understood that the charging interface protection circuit provided by the present application also includes a voltage stabilizing protection circuit 160. The input end of the reverse high-voltage resistant chip 110 is connected to the ground line through the voltage stabilizing protection circuit 160. In extreme cases, when the previous capacitor filter circuit 130, RC suppression circuit 140 and surge suppression circuit 150 all fail, the voltage stabilizing protection circuit 160 serves as the last line of protection for the built-in power supply terminal 170, further preventing the built-in power supply terminal 170 from being burned out during charging.

[0038] Reference Figure 2 It can be understood that the voltage stabilizing protection circuit 160 includes a voltage stabilizing diode D2, the cathode of the voltage stabilizing diode D2 is connected between the input end of the reverse high-voltage resistant chip 110 and the built-in power supply end 170 of the terminal device, and the anode of the voltage stabilizing diode D2 is connected to the ground wire.

[0039] Continue to refer to Figure 2 It can be understood that the charging interface protection circuit provided by the present application also includes a fifth capacitor C5 and a sixth capacitor C6, one end of the fifth capacitor C5 and the sixth capacitor C6 is connected to the input end of the reverse high-voltage resistant chip 110 and the voltage regulator diode D2, and the other end of the fifth capacitor C5 and the sixth capacitor C6 is connected to the ground line. The fifth capacitor C5 and the sixth capacitor C6 can play a filtering role. Specifically, the capacity of the fifth capacitor C5 is 1μF, the capacity of the sixth capacitor C6 is 22μF, and the rated voltage of the fifth capacitor C5 and the sixth capacitor C6 are both 6.3V, which is not limited by the present application.

[0040] Reference Figure 2 It can be understood that the charging interface protection circuit provided by the present application also includes a second resistor R2, and the reverse high-voltage resistant chip 110 is also provided with a current limit setting pin and a switch input pin. The current limit setting pin is connected to the ground wire through the second resistor R2, and the current limit setting pin is used to set the overcurrent threshold, and the switch input pin is used to send a work pause signal. The overcurrent threshold of the reverse high-voltage resistant chip 110 is determined by the blocking of the second resistor R2. When the charging connector is connected to an external device, when the current exceeds the overcurrent threshold, there may be a risk of burning the external device, and the current is cut off through the switch input pin.

[0041] Reference Figure 3 , Figure 3 The internal structure diagram of a directional high-voltage resistant chip. In this application, the model of the reverse high-voltage resistant chip 110 is FA7616AA6R, which has 6 pins, pin 1 is an output pin, pin 2 is a ground pin, pin 3 is a switch input pin, pin 4 is an enable pin, pin 5 is a current limit setting pin, and pin 6 is an input pin. Its reverse maximum cutoff voltage is 28V, which can effectively block the current from the power adapter from pin 1 through pin 6. The overcurrent threshold set for pin 5 is 6800÷the resistance value of the second resistor R2. If the resistance value of the second resistor R2 is 2.2k, the overcurrent threshold is 3A.

[0042] In the second aspect, the present application also provides a circuit board, including a charging interface protection circuit of any one of the embodiments of the first aspect. The charging interface protection circuit in the circuit board is a circuit for powering the external device by the built-in power supply terminal 170 of the terminal device when the external device is inserted into the charging interface 120. At the same time, the charging interface 120 can also charge the built-in power supply terminal 170 through another charging conversion circuit. When the charging adapter is inserted into the charging interface 120, part of the current in the charging adapter charges the built-in power supply terminal 170 from the charging conversion circuit. At the same time, part of the current will flow to the charging interface protection circuit of the present application, and the current of the charging adapter cannot flow into the output terminal of the reverse high-voltage resistant chip 110. The reverse high-voltage resistant chip 110 is provided to prevent the current from flowing from the circuit to the built-in power supply terminal 170, so as to prevent the fake adapter from directly acting on the built-in power supply terminal 170, resulting in Causes the built-in power supply terminal 170 to burn out. At the same time, in order to protect the reverse high-voltage resistant chip 110, before the current flows into the output terminal of the reverse high-voltage resistant chip 110, it first passes through the capacitor filter circuit 130 to filter the voltage of the charging adapter, and then absorbs a part of the surge voltage at the moment of the charging adapter being inserted through the RC suppression circuit 140. Finally, the surge voltage is further absorbed through the surge suppression circuit 150, and at the same time, it can withstand high surge power. That is, the capacitor filter circuit 130, the RC suppression circuit 140 and the surge suppression circuit 150 play a role in protecting the reverse high-voltage resistant chip 110, and the reverse high-voltage resistant chip 110 plays a role in protecting the built-in power supply terminal 170 of the terminal device, which can protect the built-in power supply terminal 170 from being burned out during charging, thereby extending the service life of the circuit board.

[0043] In a third aspect, the present application also provides a terminal device, comprising the circuit board of the embodiment of the first aspect.

[0044] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A charging interface protection circuit, characterized in that: Applied to terminal equipment, comprising: a charging interface, a reverse high-voltage resistant chip, a capacitor filter circuit, an RC suppression circuit and a surge suppression circuit; the charging interface is electrically connected to the output end of the reverse high-voltage resistant chip, the input end of the reverse high-voltage resistant chip is used to connect to the built-in power supply end of the terminal equipment, the charging interface and the reverse high-voltage resistant chip are connected to a ground wire through the capacitor filter circuit, the RC suppression circuit and the surge suppression circuit, the capacitor filter circuit, the RC suppression circuit and the surge suppression circuit are arranged in parallel with each other, the capacitor filter circuit is close to the position of the charging interface, the surge suppression circuit is close to the position of the output end of the reverse high-voltage resistant chip, and the RC suppression circuit is located between the capacitor filter circuit and the surge suppression circuit; Among them, the charging interface protection circuit also includes a second resistor, and the reverse high-voltage resistant chip is also provided with a current limiting setting pin and a switch input pin, the current limiting setting pin is connected to the ground wire through the second resistor, the current limiting setting pin is used to set the overcurrent threshold, and the switch input pin is used to send a work pause signal.

2. The charging port protection circuit according to claim 1, characterized in that: The capacitor filter circuit includes a first capacitor and a second capacitor, one end of the first capacitor and the second capacitor are respectively connected to the charging interface and the output end of the reverse high-voltage resistant chip, and the other end of the first capacitor and the second capacitor are connected to the ground line.

3. The charging port protection circuit according to claim 1, characterized in that: The RC suppression circuit includes a first resistor, a third capacitor and a fourth capacitor, one end of the first resistor is connected between the charging interface and the output end of the reverse high-voltage resistant chip, one end of the third capacitor and the fourth capacitor are connected to the other end of the first resistor, and the other ends of the third capacitor and the fourth capacitor are connected to the ground wire.

4. The charging port protection circuit according to claim 1, characterized in that: The surge suppression circuit includes a unidirectional TVS tube, a cathode of the unidirectional TVS tube is connected between the charging interface and the output end of the reverse high-voltage resistant chip, and a cathode of the unidirectional TVS tube is connected to a ground wire.

5. The charging port protection circuit according to claim 1, characterized in that: It also includes a voltage stabilizing protection circuit, and a ground line is connected between the input end of the reverse high-voltage resistant chip and the built-in power supply end of the terminal device through the voltage stabilizing protection circuit.

6. The charging port protection circuit according to claim 5, characterized in that: The voltage stabilizing protection circuit includes a voltage stabilizing diode, the cathode of the voltage stabilizing diode is connected between the input end of the reverse high voltage resistant chip and the built-in power supply end of the terminal device, and the anode of the voltage stabilizing diode is connected to the ground wire.

7. The charging port protection circuit according to claim 6, characterized in that: It also includes a fifth capacitor and a sixth capacitor, one end of the fifth capacitor and the sixth capacitor is connected to the input end of the reverse high-voltage resistant chip and the voltage regulator diode, and the other end of the fifth capacitor and the sixth capacitor is connected to the ground line.

8. A circuit board, characterized in that: A charging interface protection circuit comprising any one of claims 1 to 7.

9. A terminal device, characterized in that: Including the circuit board described in claim 8.

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