CN114759649A

CN114759649A - Power adapter and charging monitoring method

Info

Publication number: CN114759649A
Application number: CN202210343314.6A
Authority: CN
Inventors: 杨博圳; 杨悦
Original assignee: Shenzhen Pengshengye Electronics Co ltd
Current assignee: Shenzhen Pengshengye Electronics Co ltd
Priority date: 2022-04-02
Filing date: 2022-04-02
Publication date: 2022-07-15

Abstract

The application relates to a power adapter and a charging monitoring method, which belong to the technical field of adapters, and comprise an adapter main body and a plug, wherein the adapter main body is provided with a slot, the plug is provided with a connecting block, the connecting block is spliced with the slot, and an opening of the slot is provided with a limiting piece which is used for abutting against the connecting block; the adapter is characterized in that a circuit board is arranged in the adapter body, a wire is arranged on the plug and electrically connected with the circuit board, a containing groove is formed in the adapter body and connected with the slot, and the containing groove is used for containing the wire. The method and the device can improve the situation that the battery is difficult to charge due to insufficient space position, and can detect the abnormal charging state so as to prolong the service life of the battery.

Description

Power adapter and charging monitoring method

Technical Field

The application relates to the technical field of adapters, in particular to a power adapter and a charging monitoring method.

Background

As the frequency of use of mobile terminals increases, the mobile terminals need to be charged frequently to meet the needs of users, and the mobile terminals are generally charged by using a power adapter. The power adapter generally comprises components such as a shell, a transformer, a rectifier, a control IC (integrated circuit), a circuit board and the like, wherein the power adapter can be divided into a wall-plugging type and a desktop type according to a connection mode.

In view of the above-described related art, the inventors found the following drawbacks: in the case of a wall-mounted power adapter, when a plurality of electric appliances are powered, the spatial position of a socket may be insufficient, and it is difficult to plug the power adapter into the socket for charging.

Disclosure of Invention

In order to improve the situation that the space position of a socket is insufficient and a power adapter is difficult to plug in the socket, the application provides the power adapter and a charging monitoring method.

In a first aspect, the present application provides a power adapter, which adopts the following technical solutions:

a power adapter comprises an adapter body and a plug, wherein the adapter body is provided with a slot, the plug is provided with a connecting block, the connecting block is inserted into the slot, an opening of the slot is provided with a limiting piece, and the limiting piece is used for abutting against the connecting block; the adapter is characterized in that a circuit board is arranged in the adapter body, a wire is arranged on the plug and electrically connected with the circuit board, a containing groove is formed in the adapter body and connected with the slot, and the containing groove is used for containing the wire.

By adopting the technical scheme, in normal times, the plug is fixed in the slot through the limiting piece, and the adapter main body can be inserted into the socket; when the space of the position is not enough, the plug is detached from the adapter body, the volume of the plug is smaller than that of the adapter body, and the situation that the power adapter is difficult to plug in the socket due to the fact that the space of the socket is not enough can be improved.

Preferably, the locating part includes joint piece and compression spring, be equipped with the spout in the adapter main part, spout and slot intercommunication, joint piece and spout sliding connection, compression spring is located the spout, compression spring's one end and the lateral wall butt of spout, compression spring's the other end and joint piece butt, be equipped with the draw-in groove on the connecting block, joint piece and draw-in groove joint.

Through adopting above-mentioned technical scheme, the connecting block is pegged graft in the slot, and the joint piece is just to the draw-in groove, and at this moment, compression spring's elasticity makes joint piece joint in the draw-in groove, makes the connecting block can fix in the slot, and simultaneously, when promoting the connecting block hard, compression spring is collapsible, and then is convenient for pull down the plug from the adapter.

Preferably, be equipped with the recess in the adapter main part, recess and holding tank intercommunication, and the recess is located the holding tank and keeps away from one side of slot, be equipped with the connection piece on the wire, connection piece and recess sliding connection, the recess is close to the lateral wall of holding tank and is equipped with pressure sensor, be equipped with the monitoring module that charges on the circuit board, the monitoring module that charges includes supply circuit and MCU, supply circuit is connected with the MCU electricity, pressure sensor is connected with supply circuit, MCU electricity, be equipped with the speaker in the adapter main part, the speaker is connected with supply circuit, MCU electricity, be equipped with the piece that resets on the connection piece, the piece that resets is used for providing the elasticity of keeping away from the pressure sensor direction for the connection piece.

Preferably, the reset piece adopts a reset spring, one end of the reset spring is fixedly connected with the connecting piece, and the other end of the reset spring is fixedly connected with the side wall of the groove.

By adopting the technical scheme, the length of the charging wire of the adapter main body is limited, and the charging wire can be in a straightened state due to the limitation of distance during charging, at the moment, when a user gets up and moves again, the mobile terminal is easily pulled off, or the wire is damaged due to pulling; through set up pressure sensor in the recess, when the wire was in the state of tightening, the connection piece can extrude pressure sensor, and pressure sensor sends pressure data for MCU, and when pressure was greater than preset pressure, MCU output alarm signal, speaker sound was reported to the police, and then reducible mobile terminal was dragged and is fallen, or the condition of damage appears in the wire.

Preferably, the charging monitoring module further comprises a temperature detection circuit and an adjusting circuit, the temperature detection circuit is electrically connected with the power supply circuit and the MCU, an indicator lamp is arranged on the adapter body and electrically connected with the power supply circuit and the MCU, the adjusting circuit is electrically connected with the power supply circuit and the MCU, and the adjusting circuit is used for controlling the conduction of the charging circuit.

Preferably, the charging monitoring module further comprises a voltage detection circuit and a current detection circuit, the voltage detection circuit is electrically connected with the power supply circuit and the MCU, and the current detection circuit is electrically connected with the power supply circuit and the MCU.

Through adopting above-mentioned technical scheme, detect temperature, voltage and the electric current when charging, appear when unusual in the aspect of temperature, voltage and electric current, can be convenient for discover and in time break charging circuit.

In a second aspect, the present application provides a charging monitoring method for a power adapter, which adopts the following technical scheme:

a charging monitoring method of a power adapter is suitable for the power adapter, and comprises the following steps:

acquiring a pressure signal from a pressure sensor in real time;

judging whether the pressure signal is greater than a preset pressure or not;

if yes, an alarm signal is output to the loudspeaker.

Preferably, if yes, after outputting the alarm signal to the speaker, the method further includes:

acquiring a charging temperature in real time, and judging whether the charging temperature is greater than a preset temperature or not;

if yes, outputting a first early warning signal to the indicator light, and outputting a regulating signal to the regulating circuit.

acquiring a battery voltage in real time, and judging whether the battery voltage is higher than a first voltage and lower than a second voltage;

if so, detecting the charging current and judging whether the charging current is larger than the first current or not;

if yes, outputting a second early warning signal to the indicator lamp;

if not, outputting a third early warning signal to the indicator lamp, and outputting an adjusting signal to the adjusting circuit.

In summary, the present application includes at least one of the following beneficial technical effects:

1. when the space of the position is not enough, the plug is detached from the adapter main body, and the volume of the plug is smaller than that of the adapter main body, so that the condition that the power adapter is difficult to plug in the socket due to the fact that the space of the socket is not enough can be improved;

2. the pressure data is sent to the MCU through the pressure sensor, when the pressure is greater than the preset pressure, the MCU outputs an alarm signal to the loudspeaker, the loudspeaker gives out a sound to alarm, and therefore the situation that the mobile terminal is pulled off or a lead is damaged can be reduced;

3. through detecting temperature, voltage and the electric current when charging, appear when unusual in the aspect of temperature, voltage and electric current, can be convenient for discover and in time break charging circuit, the condition that reducible adapter main part damaged.

Drawings

FIG. 1 is a schematic structural diagram of a power adapter in an embodiment of the present application;

FIG. 2 is a top view of a power adapter in an embodiment of the present application;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2;

fig. 5 is a circuit diagram of a charge monitoring module in an embodiment of the present application.

Description of reference numerals: 10. a dispenser body; 11. a charging wire; 12. a circuit board; 13. a slot; 14. a chute; 15. accommodating grooves; 16. a groove; 17. a pressure sensor; 18. a speaker; 19. an indicator light; 20. a plug; 21. a connecting portion; 22. a conductive post; 23. connecting blocks; 24. a wire; 25. a card slot; 26. connecting sheets; 30. a limiting member; 31. a clamping block; 32. a compression spring; 40. a reset member; 50. a power supply circuit; 51. a first voltage stabilization unit; 52. a second voltage stabilization unit; 53. a temperature detection circuit; 54. a regulating circuit; 55. a voltage detection circuit; 56. a current detection circuit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is further described in detail below with reference to fig. 1-5 and the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of and not restrictive on the broad application.

The embodiment of the application discloses a power adapter, referring to fig. 1 and 2, the power adapter includes an adapter main body 10 and a plug 20, one end of the adapter main body 10 is connected with a charging wire 11, a circuit board 12 is arranged inside the adapter main body 10, and the charging wire 11 is electrically connected with the circuit board 12. The end face of the adapter body 10 far away from the charging wire 11 is provided with a slot 13, the slot 13 is provided with an opening, and the plug 20 is inserted into the slot 13.

The plug 20 comprises a connecting portion 21, a conductive column 22 and a connecting block 23, the connecting portion 21 and the connecting block 23 are integrally formed, the area of the cross section of the connecting portion 21 is smaller than that of the cross section of the connecting block 23, when the plug 20 is plugged into the slot 13, the connecting block 23 is located in the slot 13, and the connecting portion 21 extends out of the opening of the slot 13. The conductive column 22 is fixed on the connecting portion 21, a conductive line 24 is disposed on the connecting block 23, one end of the conductive line 24 is electrically connected to the conductive column 22, and the other end of the conductive line 24 is electrically connected to the circuit board 12.

When the adapter is normal, the plug 20 is fixed in the slot 13 through the limiting piece 30, and the adapter main body 10 can be plugged in the socket; when the space is not enough, the plug 20 is detached from the adapter body 10, so that the plug 20 has a small volume, and the situation that the plug is difficult to be inserted into the socket due to the insufficient space of the socket can be improved.

Referring to fig. 2 and 3, a sliding groove 14 is formed in the adapter main body 10, the sliding groove 14 is communicated with the insertion groove 13, and a limiting member 30 is disposed in the sliding groove 14, wherein the limiting member 30 includes a clamping block 31 and a compression spring 32, the clamping block 31 is in a spherical shape, and the clamping block 31 is slidably connected with the sliding groove 14. The compression spring 32 is located in the chute 14, one end of the compression spring 32 abuts against the side wall of the chute 14, and the other end of the compression spring 32 abuts against the clamping block 31. The connecting block 23 is provided with a clamping groove 25 corresponding to the clamping block 31, the section of the clamping groove 25 is arc-shaped, and the clamping block 31 is clamped with the clamping groove 25. In this embodiment, the number of the limiting members 30 is 4, and the 4 limiting members 30 are respectively located on two sides of the connecting block 23.

The connecting block 23 is inserted into the slot 13, the clamping block 31 is opposite to the clamping groove 25, and at the moment, the elastic force of the compression spring 32 enables the clamping block 31 to be clamped in the clamping groove 25, so that the connecting block 23 can be fixed in the slot 13. Meanwhile, when the connecting block 23 is pushed by force, the compression spring 32 can be contracted, so that the plug 20 can be conveniently detached from the adapter.

Referring to fig. 3 and 4, the adapter body 10 is provided with a receiving groove 15, the receiving groove 15 is communicated with the slot 13, and the receiving groove 15 is located on one side of the slot 13 close to the circuit board 12. When the plug 20 is plugged into the socket 13, the wires 24 can be flexibly received in the receiving slots 15. The adapter main body 10 is further provided with a groove 16, the groove 16 is communicated with the accommodating groove 15 through a through hole, and the groove 16 is located on one side of the accommodating groove 15 close to the circuit board 12.

The lead 24 is connected with the circuit board 12 after passing through the groove 16, a connecting sheet 26 is fixed on the lead 24, the connecting sheet 26 is connected with the groove 16 in a sliding manner, a reset piece 40 is arranged on the connecting sheet 26, in the embodiment, the reset piece 40 is a reset spring, one end of the reset spring is fixedly connected with the connecting sheet 26, and the other end of the reset spring is fixedly connected with the side wall of the groove 16. In other embodiments, return members 40 may be rubber pads. In the present embodiment, the number of the return springs is 2, and the 2 return springs are symmetrically arranged on the connecting piece 26.

Referring to fig. 4 and 5, in this embodiment, a pressure sensor 17 is disposed on a side wall of the groove 16 close to the accommodating groove 15, and a charging monitoring module is disposed on the circuit board 12, wherein the charging monitoring module includes a power supply circuit 50 and an MCU, the power supply circuit 50 is electrically connected to the MCU, and the pressure sensor 17 is electrically connected to the power supply circuit 50 and the MCU. The adapter body 10 is provided with a speaker 18, and the speaker 18 is electrically connected to the power supply circuit 50 and the MCU.

The wire 24 is pulled, at the moment, the connecting sheet 26 slides in the groove 16, the reset spring is compressed, the connecting sheet 26 can extrude the pressure sensor 17, the pressure sensor 17 sends pressure data to the MCU, when the pressure is greater than preset pressure, the MCU outputs an alarm signal, a circuit where the loudspeaker 18 is located is conducted, the loudspeaker 18 sends out a 'dripping' sound to give an alarm, and the condition that the wire 24 is damaged due to tearing off can be reduced.

In this embodiment, the charging monitoring module further includes a temperature detection circuit 53, an adjustment circuit 54, a voltage detection circuit 55, and a current detection circuit 56, wherein the temperature detection circuit 53 is electrically connected to the power supply circuit 50 and the MCU, the adjustment circuit 54 is electrically connected to the power supply circuit 50 and the MCU, and the adjustment circuit 54 is used to control the conduction of the charging circuit; the voltage detection circuit 55 is electrically connected with the power supply circuit 50 and the MCU, and the current detection circuit 56 is electrically connected with the power supply circuit 50 and the MCU.

In the present embodiment, the power supply circuit 50 includes a first voltage stabilization unit 51 and a second voltage stabilization unit 52, and an input terminal of the second voltage stabilization unit 52 is connected to an output terminal of the first voltage stabilization unit 51, where the first voltage stabilization unit 51 is configured to output a voltage of 12V, and the second voltage stabilization unit 52 is configured to output a voltage of 3.3V. The adapter main body 10 is provided with an indicator lamp 19, and the indicator lamp 19 is electrically connected with the power supply circuit 50 and the MCU; optionally, indicator light 19 includes a green LED1 and a red LED 2.

When the temperature, the charging voltage and the charging current of the battery are abnormal, the MCU controls the indicator lamp 19 to be correspondingly lightened, and controls the charging circuit to be disconnected through the adjusting circuit 54, so that the abnormal state can be found and the charging circuit can be disconnected in time, and the condition that the battery is damaged can be reduced.

In this embodiment, the adjusting circuit 54 includes a nineteenth diode D19, a forty-second resistor R42, an N-type MOS transistor Q4, an optocoupler U3, a forty-fourth resistor R40, a sixty-fourth resistor R64, a sixty-third resistor R63, a sixty-fifth resistor R65, an NPN-type triode Q7, a PNP-type triode Q8, a forty-first resistor R41, a forty-ninth resistor R49, a P-type MOS transistor Q5, a P-type MOS transistor Q6, and a forty-third resistor R43, where one end of the forty-fourth resistor R40 is connected to 3.3VCC, and the other end of the forty-fourth resistor R40 is connected to pin 1 of the optocoupler U3; an anode of the nineteenth diode D19 is connected with an EN pin of the MCU, a cathode of the nineteenth diode D19 is connected with one end of a forty-second resistor R42 and a gate of the N-type MOS transistor Q4, the other end of the forty-second resistor R42 is grounded, a drain of the N-type MOS transistor Q4 is connected with the pin 2 of the optocoupler U3, and a source of the N-type MOS transistor Q4 is grounded.

One end of a sixty-fourth resistor R64 is connected with VCC3, the other end of the sixty-fourth resistor R64 is connected with the 4 pin of the optocoupler U3 and the collector of the NPN type triode Q7, and the emitter of the NPN type triode Q7 is connected with the collector of the PNP type triode Q8. One end of a sixty-three resistor R63 is connected with a pin 3 of the optocoupler U3, and the other end of the sixty-three resistor R63 is connected with a base electrode of an NPN type triode Q7 and a base electrode of a PNP type triode Q8; one end of a sixty-five resistor R65 is connected with a pin 3 of the optocoupler U3, and the other end of the sixty-five resistor R65 is connected with an emitter of the PNP triode Q8 and GND 2.

One end of a forty-third resistor R43 is connected with VCC, the other end of the forty-third resistor R43 is connected with the source of the P-type MOS tube Q5 and the source of the P-type MOS tube Q6, the drain of the P-type MOS tube Q5 is connected with VCC, and the gate of the P-type MOS tube Q5 is connected with one end of the forty-first resistor R41, one end of the forty-ninth resistor R49 and the gate of the P-type MOS tube Q6; the other end of the forty-first resistor R41 is connected to the source of the P-type MOS transistor Q5 and the source of the P-type MOS transistor Q6, and the other end of the forty-ninth resistor R49 is connected to the collector of the PNP transistor Q8. The drain of the P-type MOS transistor Q6 is connected with DC +. The EN pin of the MCU outputs a low level (EN = 0), and at this time, the optocoupler U3 is turned off, and the P-type MOS transistor Q5 and the P-type MOS transistor Q6 are turned off, so that the charging circuit is turned off.

The implementation principle of the power adapter in the embodiment of the application is as follows: when the adapter is normal, the plug 20 is fixed in the slot 13 through the limiting piece 30, and the adapter main body 10 can be plugged in the socket; when the space is not enough, the plug 20 is detached from the adapter body 10, so that the plug 20 has a small volume, and the situation that the plug is difficult to be plugged into the socket due to the insufficient space of the socket can be improved.

The wire 24 is pulled, the connecting sheet 26 can extrude the pressure sensor 17, the pressure sensor 17 sends pressure data to the MCU, when the pressure is greater than the preset pressure, the MCU outputs an alarm signal, a circuit where the loudspeaker 18 is located is conducted, the loudspeaker 18 gives out sound to alarm, and the situation that the wire 24 is damaged due to tearing off can be reduced.

The embodiment of the application further discloses a charging monitoring method of the power adapter, which is applicable to the power adapter and comprises the following steps:

s100: the pressure signal from the pressure sensor 17 is acquired in real time.

S101: and judging whether the pressure signal is greater than the preset pressure.

S102: if so, an alarm signal is output to the speaker 18.

Specifically, the wire 24 is pulled, the connecting sheet 26 extrudes the pressure sensor 17, the pressure sensor 17 sends pressure data to the MCU, when the pressure is greater than the preset pressure, the MCU outputs an alarm signal, a circuit where the loudspeaker 18 is located is conducted, and the loudspeaker 18 sends a 'dripping' sound to give an alarm.

Optionally, after step S102, the method further includes:

s103: and acquiring the charging temperature in real time, and judging whether the charging temperature is greater than a preset temperature.

S104: if so, a first warning signal is output to the indicator lamp 19 and a regulating signal is output to the regulating circuit 54.

For example, when the temperature of the battery is detected to exceed 85 degrees, or when the reverse connection of the battery is detected, or when the power output voltage is lower than 62.5V, EN =0, BAT40V =0, LED2 blinks, and LED1 is turned off. After power-on, when the battery is not connected, EN =0, BAT40V =0, the P-type MOS transistor Q5 and the P-type MOS transistor Q6 are turned off, the LED2 is turned on, and the LED1 is turned off.

Optionally, after step S102, the method further includes:

s105: and acquiring the battery voltage in real time, and judging whether the battery voltage is higher than the first voltage and lower than the second voltage.

S106: if so, detecting the charging current and judging whether the charging current is larger than the first current or not.

S107: if so, a second warning signal is output to the indicator lamp 19.

S108: if not, a third warning signal is output to the indicator lamp 19 and an adjustment signal is output to the adjustment circuit 54.

For example, when the battery voltage is detected to be higher than 30V and lower than 40V, EN =1 and BAT40V =1, and when the detection current is 300mA or more, LED1 blinks, LED2 turns off, and EN =1 is maintained. When the detection current is 300mA or less, EN =0, and at this time, LED2 blinks and LED1 turns off. When the battery voltage is detected to be higher than 40V and lower than 62.5V, EN =1 and BAT40V = 0.

It should be clear to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional units and modules is only used for illustration, and in practical applications, the above function distribution may be performed by different functional units and modules as needed, that is, the internal structure of the device is divided into different functional units or modules, so as to perform all or part of the above described functions.

Claims

1. The power adapter is characterized by comprising an adapter main body (10) and a plug (20), wherein a slot (13) is formed in the adapter main body (10), a connecting block (23) is arranged on the plug (20), the connecting block (23) is connected with the slot (13) in an inserting mode, a limiting piece (30) is arranged at an opening of the slot (13), and the limiting piece (30) is used for abutting against the connecting block (23); be equipped with circuit board (12) in adapter main part (10), be equipped with wire (24) on plug (20), wire (24) are connected with circuit board (12) electricity, are equipped with holding tank (15) on adapter main part (10), holding tank (15) are connected with slot (13), holding tank (15) are used for placing wire (24).

2. The power adapter of claim 1, wherein the limiting member (30) comprises a clamping block (31) and a compression spring (32), the adapter body (10) is provided with a sliding groove (14), the sliding groove (14) is communicated with the slot (13), the clamping block (31) is slidably connected with the sliding groove (14), the compression spring (32) is located in the sliding groove (14), one end of the compression spring (32) is abutted to the side wall of the sliding groove (14), the other end of the compression spring (32) is abutted to the clamping block (31), a clamping groove (25) is formed in the connecting block (23), and the clamping block (31) is clamped to the clamping groove (25).

3. The power adapter of claim 1, wherein a groove (16) is formed in the adapter body (10), the groove (16) is communicated with the accommodating groove (15), the groove (16) is located on one side, away from the slot (13), of the accommodating groove (15), a connecting piece (26) is arranged on the lead (24), the connecting piece (26) is connected with the groove (16) in a sliding mode, a pressure sensor (17) is arranged on the side wall, close to the accommodating groove (15), of the groove (16), a charging monitoring module is arranged on the circuit board (12), the charging monitoring module comprises a power supply circuit (50) and an MCU (microprogrammed control unit), the power supply circuit (50) is electrically connected with the MCU, the pressure sensor (17) is electrically connected with the power supply circuit (50) and the MCU, a loudspeaker (18) is arranged on the adapter body (10), and the loudspeaker (18) and the power supply circuit (50) are arranged on the adapter body (10), The MCU is electrically connected, a resetting piece (40) is arranged on the connecting piece (26), and the resetting piece (40) is used for providing elastic force for the connecting piece (26) in the direction away from the pressure sensor (17).

4. The power adapter as claimed in claim 3, characterized in that the reset element (40) is a reset spring, one end of the reset spring is fixedly connected with the connecting piece (26), and the other end of the reset spring is fixedly connected with the side wall of the groove (16).

5. The power adapter of claim 3, wherein the charging monitoring module further comprises a temperature detection circuit (53) and an adjustment circuit (54), the temperature detection circuit (53) is electrically connected with the power supply circuit (50) and the MCU, an indicator lamp (19) is arranged on the adapter body (10), the indicator lamp (19) is electrically connected with the power supply circuit (50) and the MCU, the adjustment circuit (54) is electrically connected with the power supply circuit (50) and the MCU, and the adjustment circuit (54) is used for controlling the conduction of the charging circuit.

6. The power adapter according to claim 5, wherein the charging monitoring module further comprises a voltage detection circuit (55) and a current detection circuit (56), the voltage detection circuit (55) is electrically connected with the power supply circuit (50) and the MCU, and the current detection circuit (56) is electrically connected with the power supply circuit (50) and the MCU.

7. A charging monitoring method for a power adapter, the charging monitoring method being applied to the power adapter of any one of claims 3 to 6, the charging monitoring method comprising:

acquiring a pressure signal from a pressure sensor (17) in real time;

judging whether the pressure signal is greater than a preset pressure or not;

if yes, an alarm signal is output to a speaker (18).

8. The charge monitoring method according to claim 7, wherein if yes, after outputting the alarm signal to the speaker (18), further comprising:

if yes, a first warning signal is output to the indicator lamp (19), and a regulation signal is output to the regulation circuit (54).

9. The charge monitoring method according to claim 7, wherein if yes, after outputting the alarm signal to the speaker (18), further comprising:

if yes, outputting a second early warning signal to an indicator lamp (19);

if not, a third warning signal is output to the indicator lamp (19), and an adjustment signal is output to the adjustment circuit (54).