TWI436538B - Port detection and protection circuit and electronic device using the same - Google Patents

Description

埠Automatic detection and protection circuit and electronic device using the same

The invention relates to a cymbal automatic detection protection circuit and an electronic device using the same.

At present, the data machine has both an Asymmetric Digital Subscriber Loop (ADSL) and an External Exchange Station (FXS), and the user can set up a Public Switched Telephone Network (PSTN) telephone line. Plug in the ADSL network and connect the IP phone to the FXS for Voice over IP (VoIP) calls. However, ADSL埠 and FXS埠 are externally connected by telephone lines, which is easy to be confused. Therefore, users can easily insert PSTN telephone lines into FSX埠, resulting in Subscriber Line Interface Circuit (SLIC). ) damage.

An automatic detection and protection circuit is connected between a Tip signal line, a Ring signal line and a Subscriber Line Interface Circuit (SLIC) for detecting whether the Tip signal line and the Ring signal line are normal, wherein the Tip signal is The line, the Ring signal line and the SLIC circuit are in an off state in a normal state, and include a first voltage detecting circuit, a second voltage detecting circuit, a ring detecting circuit, a first logic element, a second logic element, a switching circuit, and a reference voltage circuit. And alarm circuit . The first voltage detecting circuit is configured to detect a voltage difference between the Tip signal and the Ring signal, and output a first detection signal. The second voltage detecting circuit is configured to detect a voltage difference between the Tip signal and the Ring signal, and output a second detection signal. The ringing detection circuit is connected to the SLIC circuit for detecting whether there is an incoming call and outputting a third detection signal. The first logic component is configured to output the first logic signal according to the first detection signal and the third detection signal. The second logic component outputs the second logic signal according to the second detection signal and the third detection signal. The switching circuit is connected between the Tip signal line, the Ring signal line and the SLIC circuit, and is configured to turn on or off the Tip signal line, the Ring signal line and the SLIC circuit according to the first logic signal. The reference voltage circuit is connected to the switching circuit for providing a reference voltage to the Tip signal line and the Ring signal line, so that the first voltage detecting circuit and the second voltage detecting circuit detect whether the Tip signal line and the Ring signal line are normal. The alarm circuit is configured to perform an alarm according to the second logic signal.

An electronic device is connected to the Tip signal line and the Ring signal line, and includes a SLIC circuit and an automatic detection and protection circuit connected between the Tip signal line, the Ring signal line and the SLIC circuit. The SLIC circuit is disconnected from the Tip signal line and the Ring signal line in a normal state. The 埠 automatic detection protection circuit includes a first voltage detection circuit, a second voltage detection circuit, a ring detection circuit, a first logic element, a second logic element, a switching circuit, a reference voltage circuit, and an alarm circuit. The first voltage detecting circuit is configured to detect a voltage difference between the Tip signal and the Ring signal, and output a first detection signal. The second voltage detecting circuit is configured to detect a voltage difference between the Tip signal and the Ring signal, and output a second detection signal. The ringing detection circuit is connected to the SLIC circuit for detecting whether there is an incoming call and outputting a third detection signal. The first logic component is configured to output the first logic signal according to the first detection signal and the third detection signal. The second logic component outputs the second logic signal according to the second detection signal and the third detection signal. The switching circuit is connected between the Tip signal line, the Ring signal line and the SLIC circuit, and is used according to the first logic The signal turns on or off the Tip signal line, the Ring signal line and the SLIC circuit. The reference voltage circuit is connected to the switching circuit for providing a reference voltage to the Tip signal line and the Ring signal line, so that the first voltage detecting circuit and the second voltage detecting circuit detect whether the Tip signal line and the Ring signal line are normal. The alarm circuit is configured to perform an alarm according to the second logic signal.

In the embodiment of the present invention, the Tip signal line, the Ring signal line and the SLIC circuit are in a disconnected state in a normal state, and the line is only when the phone connected between the Tip signal line and the Ring signal line is in an off-hook or incoming call state. It can be switched on to avoid the impact of the surge signal. Moreover, the automatic detection protection circuit detects whether the user accidentally inserts the ADSL telephone line into the FXS, and uses the alarm circuit to give an alarm prompt, and simultaneously cuts off the external Tip signal line and the Ring signal line and the internal SLIC circuit, thereby ensuring the SLIC. The circuit will not be damaged.

1‧‧‧Electronic equipment

10‧‧‧埠Automatic detection and protection circuit

100‧‧‧Differential circuit

110‧‧‧First voltage detection circuit

120‧‧‧Second voltage detection circuit

130‧‧‧First logic element

140‧‧‧Second logic component

150‧‧‧Switching circuit

160‧‧‧reference voltage circuit

170‧‧‧Ring detection circuit

180‧‧‧ alarm circuit

20‧‧‧SLIC circuit

R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13‧‧‧ resistance

D11, D12‧‧‧Differential Comparator

A1, A2, A3, A4, A5‧‧‧ comparator

D1, D2‧‧‧ diode

SW‧‧ switch

C1‧‧‧ capacitor

Q1, Q2‧‧‧O crystal

1 is a block diagram of an electronic device according to the present invention; and FIG. 2 is a specific circuit diagram of the 埠 automatic detection and protection circuit of FIG.

FIG. 1 is a block diagram of an electronic device 1 of the present invention. The electronic device 1 includes an automatic detection and protection circuit 10 and a Subscriber Line Interface Circuit (SLIC) 20. Since the telephone line has two signal lines, respectively a Tip signal line and a Ring signal line, when the telephone is inserted into the FXS of the electronic device 1, the electronic device 1 is connected to the Tip signal line and the Ring signal line, and at the same time, the automatic detection The test protection circuit 10 is connected between the Tip signal line, the Ring signal line and the SLIC circuit 20 for detecting whether the Tip signal line and the Ring signal line are normal, thereby ensuring that the SLIC circuit 20 inside the electronic device 1 is not damaged. Among them, SLIC circuit 20 loses SLIC_Tip signal and SLIC_Ring signal. It should be noted that, in this embodiment, the Tip signal line, the Ring signal line, and the SLIC circuit 20 are in an off state in a normal state (ie, a non-off-hook and an incoming call state), and are only connected to the Tip signal line and the Ring signal line. The above circuit can be turned on when the phone is in the off-hook or incoming call state.

In this embodiment, the automatic detection protection circuit 10 includes a difference circuit 100, a first voltage detection circuit 110, a second voltage detection circuit 120, a first logic element 130, a second logic element 140, a switching circuit 150, and a reference voltage circuit 160. The ringing detection circuit 170 and the alarm circuit 180.

The difference circuit 100 is configured to perform a differential operation between the Tip signal and the Ring signal, and output a difference between the Tip signal and the Ring signal voltage to the first voltage detecting circuit 110 and the second voltage detecting circuit 120. The first voltage detecting circuit 110 is configured to detect whether the voltage difference between the Tip signal and the Ring signal falls within the first preset range, and output the first detection signal. In the present embodiment, the first preset range is 4.8V~15V, which is obtained according to the normal operation of the electronic device 1, that is, the voltage measured when the IP phone is correctly inserted into the FXS. The second voltage detecting circuit 120 is configured to detect whether the voltage difference between the Tip signal and the Ring signal does not fall within the second preset range, that is, whether the voltage difference between the Tip signal line and the Ring signal line is greater than a second preset range. The maximum value is less than the minimum value in the second preset range, and the second detection signal is output. In this embodiment, the second preset range is 1.5V~39V, the maximum value is 39V, and the minimum value is 1.5V, and the second preset range is the voltage measured when the ADSL telephone line is mistakenly inserted into the FXS埠. And got it.

The ringing detection circuit 170 is connected to the SLIC circuit 20 for detecting whether there is an incoming call according to the voltage difference between the SLIC_Tip signal and the SLIC_Ring signal, and outputting a third detection signal. The first logic component 130 outputs the first according to the first detection signal and the third detection signal. The logic signal, the second logic component 140 outputs the second logic signal according to the second detection signal and the third detection signal. The switching circuit 150 is connected between the Tip signal line, the Ring signal line and the SLIC circuit 20 for turning on or off the Tip signal line, the Ring signal line and the SLIC circuit 20 according to the first logic signal. The alarm circuit 180 is configured to perform an alarm according to the second logic signal. The reference voltage circuit 160 is connected to the switching circuit 150 for providing a reference voltage source for the Tip signal line and the Ring signal line, for example, 18V, so that the first voltage detecting circuit 110 and the second voltage detecting circuit 120 detect the Tip signal line and the Ring. Is the signal line normal?

When the user inserts the IP telephone line into the FXS, and the telephone is in the off-hook state, the telephone connected between the Tip signal line and the Ring signal line is equivalent to a resistance of 600, which forms a loop with the reference voltage circuit 160 and the switching circuit 150. . At this time, the reference voltage circuit 160 and the Tip signal line and the Ring signal line simultaneously supply the input voltage signal to the differential circuit 100, and then output to the first voltage detecting circuit 110 and the second voltage detecting circuit 120. In this case, the voltage difference between the Tip signal line and the Ring signal line falls within the first predetermined range, and the first voltage detecting circuit 110 outputs a high level. However, the voltage difference is not higher than the maximum value of the second preset range, and is not lower than the minimum value in the second preset range. Therefore, the second voltage detecting circuit 120 also outputs a high level. At this time, the ringing detection circuit 170 detects whether there is an incoming call signal, and if there is an incoming call, the ringing detecting circuit 170 outputs a high level, and if there is no incoming call, the ringing detecting circuit 170 outputs a low level. In this embodiment, the first logic element 130 is an OR gate, and the second logic element 140 is a NOR gate. Regardless of whether there is an incoming call, the first logic component 130 outputs a first logic signal of a high level, so that the switching circuit 150 connects the SLIC circuit 20 with the Tip signal line and the Ring signal line, and the user can make a VoIP call. The second logic element 140 outputs a low level such that the alarm circuit 180 does not alarm.

When the telephone is in the on-hook state, the Tim signal line and the Ring signal line are disconnected from the reference voltage circuit 160 and the switching circuit 150, and the voltage difference between the Tip signal line and the Ring signal line is the reference provided by the reference voltage circuit 160. The voltage is 18V, and the reference voltage does not fall within the first preset range, and is not higher than the second preset range maximum value or lower than the second preset range minimum value. Therefore, the first voltage detecting circuit 110 outputs a low level, and the second voltage detecting circuit outputs a high level. At this time, if there is an incoming call signal, the ring detecting circuit 170 outputs a high level, the first logic element 130 also outputs a high level, so that the switching circuit 150 connects the SLIC circuit 20 with the Tip signal line and the Ring signal line. Users can make VoIP calls. At the same time, the second logic component 140 outputs a second logic signal of a low level, so that the alarm circuit 180 does not operate, that is, no alarm signal is generated. If there is no incoming signal, the ring detecting circuit 170 outputs a low level, and the first logic element 130 outputs a low level, thereby disconnecting the SLIC circuit 20 from the Tip signal line and the Ring signal line. Then, the second logic component 140 also outputs a second logic signal of a low level, so that the alarm circuit 180 does not work, that is, no alarm signal is generated.

It is noted that when there is an incoming call signal, the voltage of the incoming call signal is higher than the maximum value of the second preset range, and the second logic component 140 integrates the second detection signal and the third detection signal to perform an alarm driving. The third detection signal outputted by the ringing detection circuit 170 can suppress the alarm circuit 180 from false alarming due to an incoming call when the electronic device 1 is in normal operation. Moreover, the switching circuit 150 switches to the SLIC circuit 20 only when the electronic device 1 is operating normally, and is connected to the reference voltage circuit 160 at other times.

If the user mistakenly inserts the ADSL telephone line into the FXS, the voltage between the Tip signal line and the Ring signal line differs by 48V, and the loop formed by the reference voltage circuit 160, the switching circuit 150, the Tip signal line, and the Ring signal line is equivalent to an open circuit. Differential circuit 100 Directly receive the voltage signal of the Tip signal line and the Ring signal line. Because the voltage difference between the Tip signal line and the Ring signal line does not fall within the first preset range, the voltage difference is greater than the maximum value of the second preset range or less than the minimum value of the second preset range. . Therefore, the first voltage detecting circuit 110 outputs a first detecting signal of a low level, and the second voltage detecting circuit 120 also outputs a second detecting signal of a low level. In this embodiment, the automatic detection and protection circuit 10 preferentially detects whether the external Tip signal line and the Ring signal line are incorrect. When the user detects that the ADSL telephone line is mistakenly inserted into the FXS, the second logic component 140 outputs a high level, thereby driving the alarm circuit 180 to alarm, and the first logic component 130 switches the switching circuit 150 to the reference voltage circuit 160. If there is an incoming call signal at a certain time after the erroneous insertion, the first logic component 130 outputs a high level, so that the switching circuit 150 switches to the SLIC circuit 20. Since the incoming signal voltage is higher than 48V, the signal cannot be transmitted from the Tip signal line. The Ring signal line flows to the SLIC circuit 20 to ensure that the SLIC circuit 20 is not damaged in this case. At this time, the second logic element 140 outputs a low level, and the alarm circuit 180 stops the alarm until there is no incoming call signal input. Although the alarm circuit 180 does not alarm during the presence of the incoming call signal, when the user mistakenly inserts the ADSL telephone line into the FXS, the alarm circuit 180 has notified the user that the electronic device 1 is in an abnormal working state at this time, that is, the electronic device 1 first It will judge whether the ADSL telephone line is mistakenly inserted into FXS, and then it is judged whether there is an incoming call.

FIG. 2 is a specific circuit diagram of the 埠 automatic detection protection circuit 10 of FIG. The differential circuit 100 includes resistors R1, R2, R3, and R4 and a first differential comparator D1. The positive input terminal of the first differential comparator D1 receives the Tip signal, the negative input terminal receives the Ring signal, and the output terminal outputs a voltage difference signal between the Tip signal and the Ring signal. The resistor R1 is connected in series to the Tip signal line, and the resistor R2 is connected in series on the Ring signal line. The resistor R3 is connected between the positive input terminal of the first differential comparator D1 and the common node of the resistor R1 and the ground. The resistor R4 is connected to the negative input terminal of the first differential comparator D1 and the resistor R2 The common node is between the output of the first differential comparator D1.

The first voltage detecting circuit 110 includes a first comparator A1, a second comparator A2, and a third logic element U1. The positive input terminal of the first comparator A1 receives the first reference voltage signal Vref1, for example: 15V, the negative input terminal receives the voltage difference signal of the Tip signal and the Ring signal, and the output end thereof is used for outputting the first comparison signal. The positive input terminal of the second comparator A2 receives the voltage difference signal of the Tip signal and the Ring signal, and the negative input terminal receives the second reference voltage signal Vref2, for example: 4.8V, and the output end thereof is used for outputting the second comparison signal. The third logic component U1 outputs the first detection signal according to the first comparison signal and the second comparison signal.

The second voltage detecting circuit 200 includes a third comparator A3, a fourth comparator A4, and a fourth logic element U2. The positive input terminal of the third comparator A3 receives the third reference voltage Vref3, for example: 39V, the negative input terminal receives the voltage difference signal of the Tip signal and the Ring signal, and the output end outputs the third comparison signal. The positive input terminal of the fourth comparator A4 receives the voltage difference signal of the Tip signal and the Ring signal, and the negative input terminal receives the fourth reference voltage signal Vref4, for example: 1.5V, and the output terminal outputs a fourth comparison signal. The fourth logic component U2 is configured to output a second voltage detection signal according to the third comparison signal and the fourth comparison signal.

The ringing detection circuit 170 includes a second differential circuit 1701 and a fifth comparator A5. The specific circuit component and the connection relationship of the second difference circuit 1701 are substantially the same as those of the first difference circuit 100, and include the resistors R5, R6, R7, and R8 and the second differential comparator D2, respectively, except that the resistor R5 is connected in series to the SLIC circuit 20. On the SLIC_Tip signal line, the resistor R6 is connected in series to the SLIC_Ring signal line of the SLIC circuit 20. The positive input terminal of the fifth comparator D5 receives the SLIC_Tip signal and the SLIC_Ring signal voltage difference signal, and the negative input terminal receives the fifth reference voltage signal Vref5, for example: 56V, the output thereof The terminal outputs the third detection signal. When an incoming call is detected, the fifth comparator A5 outputs a high level, and vice versa, outputs a low level.

The switching circuit 150 includes a first transistor Q1, a resistor R9, a first diode D1, and a double-pole double-throw switch SW. The base of the first transistor Q1 receives the first logic signal, and the emitter is grounded. The resistor R9 is connected between the base of the first transistor Q1 and the external power source Vcc. The anode of the first diode D1 is connected to the base of the first transistor Q1, and the cathode thereof is connected to the external power source Vcc. The double pole double throw switch SW has a magnetic element m, a first fixed end a, a second fixed end b, a first free end c, a second free end d, a third free end e, and a fourth free end f. Wherein, the magnetic element m is connected between the base of the first switching element Q1 and the external power source, the first fixed end a is connected in series on the Tip signal line, the second fixed end b is connected in series on the Ring signal line, the first free end c and the reference The voltage circuit 160 is connected, the second free end d is connected in series on the SLIC_Tip signal line, the third free end e is connected in series on the SLIC_Ring signal line, and the fourth free end f is grounded. When the first transistor Q1 is turned on, the external power source Vcc forms a discharge loop through the magnetic element m, the first diode D1 and the first transistor Q1.

The reference voltage circuit 160 includes a second diode D2 and a resistor R10, wherein the anode of the second diode D2 receives a sixth reference voltage Vref 6, for example, 18V, and the resistor R10 is connected to the cathode of the second diode D2. The first free end c of the double pole double throw switch SW. Among them, the resistance of the resistor R10 is about 600.

The alarm circuit 180 includes resistors R11, R12, R13, a capacitor C1, a second transistor Q2 and a speaker. The base of the second transistor Q2 is coupled to the output of the second logic element 140 via a resistor R11, the emitter of which is grounded, and the base of which is coupled to the speaker. At the same time, the speaker is also connected to the external power source Vcc through the resistor R13, and the capacitor C1 and the resistor R12 are connected in parallel between the base of the second transistor Q2 and the ground.

In this embodiment, when the electronic device 1 is working normally, and the telephone connected between the Tip signal line and the Ring signal line is in the off-hook state, the voltage of the Tip signal line and the Ring signal line received by the first voltage detecting circuit 110 is When the difference is between 4.8V and 15V, the first comparator A1 and the second comparator A2 both output a high level. In the present embodiment, when the third logic element U1 is an AND gate, a high level is output. At this time, the third comparator A3 and the fourth comparator A4 both output a high level, and the fourth logic element U2 is a NAND gate, and outputs a high level. Therefore, regardless of whether the ringing detection circuit 170 detects an incoming call signal, that is, regardless of whether the fifth comparator A5 outputs a high level or a low level, the first voltage detecting circuit 110 outputs a first detection signal of a high level, and the second voltage detection The circuit 120 outputs a second detection signal of a low level. At this time, the first transistor Q1 is turned on, the external power source Vcc starts supplying power, and the current passes through the magnetic element m, the first diode D1, the resistor R9, and the first transistor Q1 to the ground. When a current flows through the magnetic element m, a magnetic force is generated thereon so that the fixed end a of the double-pole double-throw switch SW is connected to the second free end d, and the fixed end b is connected to the third sub-end e, thereby switching The circuit 150 connects the external Tip signal line and the Ring signal line to the SLIC_Tip signal line of the internal SLIC circuit 20 and the SLIC_Ring signal line. At the same time, since the second logic element 140 outputs a low level, the second transistor Q2 is not turned on, and the circuit composed of the external power source Vcc, the speaker and the first transistor Q1 is open, and the speaker does not alarm.

When the telephone is in the on-hook state, the voltage difference between the Tip signal line and the Ring signal line is 18V, the first voltage detecting circuit 110 outputs a low level, and the second voltage detecting circuit outputs a high level. If there is an incoming call signal, the first logic component 130 outputs a high level, so that the switching circuit 150 connects the external Tip signal line and the Ring signal line with the SLIC_Tip signal line of the internal SLIC circuit 20 and the SLIC_Ring signal line. Since the second logic element 140 outputs a low level, the second transistor Q2 is not turned on, and the circuit composed of the external power source Vcc, the speaker and the first transistor Q1 is open, and the speaker does not alarm. If not The incoming signal, the first logic element 130 outputs a low level, and the first transistor Q1 is turned off, then no current passes through the magnetic element m, so that no magnetic force is generated. Therefore, the switching circuit 150 disconnects the external Tip signal line and the Ring signal line from the SLIC_Tip signal line of the internal SLIC circuit 20 and the SLIC_Ring signal line. Likewise, the second logic element 140 outputs a low level so that the alarm circuit 180 does not alarm.

When the electronic device 1 is abnormal, the voltage difference between the Tip signal line and the Ring signal line is 48V, which does not fall within the first preset range of 4.8V~15V, and is greater than the maximum value of the second preset range of 39V. The first comparator A1 and the second comparator A2 both output a low level, so the third logic element U1 outputs a low level. The third comparator A3 and the fourth comparator A4 both output a low level, so the fourth logic element U2 also outputs a low level. Then, the first logic element 130 outputs a high level when the ring detecting circuit 170 detects an incoming call. At this time, the switching circuit 150 connects the external Tip signal line and the Ring signal line with the SLIC_Tip signal line of the internal SLIC circuit 20 and the SLIC_Ring signal line. However, the incoming signal voltage is higher than the voltage difference between the external Tip signal line and the Ring signal line, and the signal cannot be transmitted from the external Tip signal line and the Ring signal line to the SLIC circuit 20, thereby ensuring that the SLIC circuit 20 is not damaged. The first logic element 130 outputs a low level when the ring detecting circuit 170 detects no incoming call. At this time, the switching circuit 150 connects the reference voltage circuit 160 with the external Tip signal line and the Ring signal line to form a loop, that is, the fixed end a of the double-pole double-throw switch SW is connected to the first free end c, and the fixed end b Connected to the fourth free end f. At the same time, due to the abnormal initial moment of the electronic device 1, the second logic element 140 outputs a high level, the second transistor Q2 is turned on, the external power source Vcc starts to supply power, and the current passes through the resistor R11, the speaker, and the second transistor Q2 to the ground. The speaker starts to alarm because there is current flowing through the speaker. When the ring detecting circuit 170 detects an incoming call at a certain moment, the second logic element 140 outputs a low level, and the alarm circuit 180 stops the alarm. It is worth noting that due to the Tip signal line and the Ring signal line The polarity of the transmitted voltages can be interchanged, so the voltage difference between the two can be positive or negative. Therefore, in other embodiments of the present invention, the voltage difference between the Tip signal line and the Ring signal line may be less than 1.5V.

The auto-detection protection circuit 10 of the present invention is not limited to the circuit diagram shown in FIG. 2, and can be implemented by other circuits that can implement the same function. In other embodiments of the present invention, the first differential circuit 100 and the second differential circuit 1701 can be added to the voltage dividing circuit before, and the reference voltages Vref1, Vref2, Vref3, Vref4, and Vref5 are proportionally reduced. Next, the comparators A1, A2, A3, A4, and A5 can select components with lower cost.

In the present invention, the Tip signal line, the Ring signal line and the SLIC circuit are in a disconnected state in a normal state, and the line can be connected only when the telephone connected between the Tip signal line and the Ring signal line is in an off-hook or incoming call state. Pass to avoid the impact of the surge signal. Moreover, the electronic device 1 uses the 埠 automatic detection protection circuit 10 to detect whether the user mistakenly inserts the ADSL telephone line into the FXS ,, and simultaneously uses the alarm circuit 180 to make an alarm prompt, and cuts off the external Tip signal line and the Ring signal line and the internal The SLIC circuit 20 is connected to ensure that the SLIC circuit 20 is not damaged when the electronic device 1 is abnormally operated.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art of the present invention should be included in the following claims.

1‧‧‧Electronic equipment

10‧‧‧埠Automatic detection and protection circuit

100‧‧‧Differential circuit

110‧‧‧First voltage detection circuit

120‧‧‧Second voltage detection circuit

130‧‧‧First logic element

140‧‧‧Second logic component

150‧‧‧Switching circuit

160‧‧‧reference voltage circuit

170‧‧‧Ring detection circuit

180‧‧‧ alarm circuit

20‧‧‧SLIC circuit

Claims (20)

An automatic detection and protection circuit is connected between a Tip signal line, a Ring signal line and a Subscriber Line Interface Circuit (SLIC) for detecting whether the Tip signal line and the Ring signal line are normal, wherein the SLIC The circuit outputs a SLIC_Tip signal and a SLIC_Ring signal, and the Tip signal line, the Ring signal line and the SLIC circuit are in an off state in a normal state, wherein the 埠 automatic detection protection circuit comprises: a first voltage detecting circuit for detecting a Tip signal The first voltage detection circuit includes: a first comparator, the positive input terminal receives the first reference voltage signal, and the negative input terminal receives the Tip signal and the RING signal The voltage difference signal has an output terminal for outputting the first comparison signal, and a second comparator, the positive input terminal receives the voltage difference signal of the Tip signal and the Ring signal, and the negative input terminal receives the second reference voltage signal, The output end is configured to output a second comparison signal; and the third logic component is configured to output according to the first comparison signal and the second comparison signal The first detection signal; the second voltage detection circuit is configured to detect a voltage difference between the Tip signal and the Ring signal, and output a second detection signal; a ring detection circuit is connected to the SLIC circuit for detecting whether there is an incoming call, And outputting a third detection signal; the first logic component is configured to output the first logic signal according to the first detection signal and the third detection signal; and the second logic component is configured to perform the third detection signal according to the second detection signal Signal output second logic The switching circuit is connected between the Tip signal line, the Ring signal line and the SLIC circuit, for turning on or off the Tip signal line, the Ring signal line and the SLIC circuit according to the first logic signal a reference voltage circuit connected to the switching circuit for providing a reference voltage to the Tip signal line and the Ring signal line, so that the first voltage detecting circuit and the second voltage detecting circuit detect the Tip signal line and the Ring Whether the signal line is normal; and an alarm circuit for performing an alarm according to the second logic signal. The automatic detection and protection circuit of the first aspect of the invention, wherein the first voltage detection circuit is configured to detect whether a voltage difference between the Tip signal and the ping signal falls within a first preset range, the second The voltage detecting circuit is configured to detect whether the voltage difference between the Tip signal and the Ring signal does not fall within a second preset range. The automatic detection and protection circuit as described in claim 1, further comprising a first difference circuit, configured to perform a difference operation between the Tip signal and the Ring signal, and output a voltage difference between the Tip signal and the Ring signal. The signal is applied to the first voltage detecting circuit and the second voltage detecting circuit. The automatic detection and protection circuit of claim 3, wherein the first differential circuit comprises: a first differential comparator, the positive input terminal receives the Tip signal, the negative input terminal receives the Ring signal, and the output end Outputting a voltage difference signal between the Tip signal and the Ring signal; a first resistor connected in series to the Tip signal line; a second resistor connected in series to the Ring signal line; and a third resistor connected to the positive input of the first differential comparator a terminal and the common node of the first resistor and the ground; and a fourth resistor connected to the common input of the first differential comparator and the second resistor The node is between the output of the first differential comparator. The automatic detection and protection circuit of the first aspect of the invention, wherein the second voltage detection circuit comprises: a third comparator, wherein a positive input terminal receives a third reference voltage, and a negative input terminal receives the Tip signal and The voltage difference signal of the Ring signal has a third comparison signal outputted by the output end; the fourth comparator has a positive input terminal receiving the voltage difference signal of the Tip signal and the Ring signal, and a negative input terminal receiving the fourth reference voltage signal, The output terminal outputs a fourth comparison signal; and the fourth logic component is configured to output the second detection signal according to the third comparison signal and the fourth comparison signal. The automatic detection and protection circuit as described in claim 1, wherein the ring detection circuit comprises: a second difference circuit, configured to perform a difference operation between the received SLIC_Tip signal and the SLIC_Ring signal, and output the SLIC_Tip a voltage difference signal between the signal and the SLIC_Ring signal; and a fifth comparator, the positive input terminal receives the SLIC_Tip signal and the SLIC_Ring signal voltage difference signal, the negative input terminal receives the fifth reference voltage signal, and the output terminal outputs the third Detection signal. The automatic detection and protection circuit of the first aspect of the invention, wherein the second differential circuit comprises: a second differential comparator, wherein the positive input terminal receives the SLIC_Tip signal, the negative input terminal receives the SLIC_Ring signal, and the output end Outputting a voltage difference signal between the SLIC_Tip signal and the SLIC_Ring signal; a fifth resistor connected in series to the SLIC_Tip signal line; and a sixth resistor connected in series on the SLIC_Ring signal line; a seventh resistor connected between the positive input terminal of the second differential comparator and the common node of the fifth resistor; and an eighth resistor connected to the negative input terminal of the second differential comparator and the sixth Between the common node of the resistor and the output of the second differential comparator. The automatic detection and protection circuit as described in claim 1, wherein the switching circuit comprises: a first transistor, a base receiving the first logic signal, and an emitter grounded; and a ninth resistor connected to the a base of the first transistor and an external power source; a first diode having an anode connected to a base of the first transistor, a cathode connected to the external power source; and a double-pole double-throw switch having a magnetic An element, a first fixed end, a second fixed end, a first free end, a second free end, a third free end, and a fourth free end; wherein the magnetic element is connected to the base and external power of the first transistor The first fixed end is connected in series to the Tip signal line, the second fixed end is connected in series to the Ring signal line, the first free end is connected to the voltage reference circuit, and the second free end is connected in series to the SLIC_Tip signal line. The third free end is connected in series to the SLIC_Ring signal line, and the fourth free end is grounded. The automatic detection and protection circuit as described in claim 8 , wherein the reference voltage circuit comprises: a second diode having an anode receiving a sixth reference voltage; and a tenth resistor connected to the second diode The cathode is between the first free end of the double pole double throw switch. The 埠 automatic detection protection circuit according to claim 1, wherein the alarm circuit comprises: a second transistor having a base connected to an output end of the second logic element and an emitter grounded; a resistor connected to the base of the second transistor and the output of the second logic element a twelveth resistor; a capacitor connected in parallel with the twelfth resistor between the base of the second transistor and the ground; and a speaker connected to the base and the external power source of the second transistor; And a thirteenth resistor connected between the external power source and the speaker. An electronic device is connected to a Tim signal line and a Ring signal line, wherein the electronic device includes: a SLIC circuit for outputting a SLIC_Tip signal and a SLIC_Ring signal; wherein the SLIC circuit is in a normal state and the Tip signal line and the Ring signal line In the disconnected state; and the automatic detection and protection circuit is connected between the Tip signal line, the Ring signal line and the SLIC circuit, for detecting whether the Tip signal line and the Ring signal line are normal, including: The voltage detecting circuit is configured to detect a voltage difference between the Tip signal and the Ring signal, and output a first detecting signal. The first voltage detecting circuit includes: a first comparator, the positive input terminal receives the first reference voltage signal, and the negative input thereof The terminal receives the voltage difference signal of the Tip signal and the Ring signal, and the output end is used for outputting the first comparison signal; the second comparator receives the voltage difference signal of the Tip signal and the Ring signal, and the negative input thereof. Receiving a second reference voltage signal, the output end is configured to output a second comparison signal; and the third logic component is configured to use the first comparison signal and the first The comparison signal outputs the first detection signal; the second voltage detection circuit is configured to detect a voltage difference between the Tip signal and the Ring signal, and output a second detection signal; a ring detection circuit is connected to the SLIC circuit for detecting whether Having an incoming call and outputting a third detection signal; the first logic component is configured to output the first logic according to the first detection signal and the third detection signal a second logic component, configured to output a second logic signal according to the second detection signal and the third detection signal; and a switching circuit connected between the Tip signal line, the Ring signal line and the SLIC circuit, Turning on or off the Tip signal line, the Ring signal line and the SLIC circuit according to the first logic signal; and the reference voltage circuit is connected to the switching circuit for providing reference to the Tip signal line and the Ring signal line. a voltage, so that the first voltage detecting circuit and the second voltage detecting circuit detect whether the Tip signal line and the Ring signal line are normal; and an alarm circuit for performing an alarm according to the second logic signal. The electronic device of claim 11, wherein the first voltage detecting circuit is configured to detect whether a voltage difference between the Tip signal and the Ring signal falls within a first preset range, and the second voltage detecting circuit is used. And detecting whether the voltage difference between the Tip signal and the Ring signal does not fall within a second preset range. The electronic device of claim 11, further comprising a first difference circuit, configured to perform a differential operation between the Tip signal and the Ring signal, and output a voltage difference signal between the Tip signal and the Ring signal to the first a voltage detecting circuit and a second voltage detecting circuit. The electronic device of claim 13, wherein the first differential circuit comprises: a first differential comparator, the positive input terminal receives the Tip signal, the negative input terminal receives the Ring signal, and the output terminal outputs the Tip signal a voltage difference signal of the Ring signal; a first resistor connected in series to the Tip signal line; a second resistor connected in series to the Ring signal line; and a third resistor connected to the positive input terminal of the first differential comparator and the first a common node of a resistor and ground; and a fourth resistor connected to the common input of the first differential comparator and the second resistor The node is between the output of the first differential comparator. The electronic device of claim 11, wherein the second voltage detecting circuit comprises: a third comparator, wherein the positive input terminal receives the third reference voltage, and the negative input terminal receives the Tip signal and the Ring signal The voltage difference signal has an output terminal outputting a third comparison signal; the fourth comparator has a positive input terminal receiving the voltage difference signal of the Tip signal and the Ring signal, and a negative input terminal receiving the fourth reference voltage signal, and the output end thereof outputs a fourth comparison signal; and a fourth logic component, configured to output the second detection signal according to the third comparison signal and the fourth comparison signal. The electronic device of claim 11, wherein the ringing detection circuit comprises: a second difference circuit, configured to perform a difference operation between the received SLIC_Tip signal and the SLIC_Ring signal, and output the SLIC_Tip signal and the SLIC_Ring The voltage difference signal of the signal; and the fifth comparator, the positive input terminal receives the SLIC_Tip signal and the SLIC_Ring signal voltage difference signal, the negative input terminal receives the fifth reference voltage signal, and the output terminal outputs the third detection signal. The electronic device of claim 11, wherein the second differential circuit comprises: a second differential comparator, wherein the positive input terminal receives the SLIC_Tip signal, the negative input terminal receives the SLIC_Ring signal, and the output terminal outputs the SLIC_Tip signal a voltage difference signal with the SLIC_Ring signal; a fifth resistor connected in series to the SLIC_Tip signal line; a sixth resistor connected in series to the SLIC_Ring signal line; and a seventh resistor connected to the positive input terminal of the second differential comparator and the first Between the common node of the five resistors and the ground; The eighth resistor is connected between the negative input terminal of the second differential comparator and the common node of the sixth resistor and the output of the second differential comparator. The electronic device of claim 11, wherein the switching circuit comprises: a first transistor having a base receiving the first logic signal and an emitter grounded; and a ninth resistor connected to the first transistor a base body and an external power source; a first diode having an anode connected to a base of the first transistor, a cathode connected to the external power source; and a double-pole double-throw switch having a magnetic element, first a fixed end, a second fixed end, a first free end, a second free end, a third free end, and a fourth free end; wherein the magnetic element is connected between the base of the first transistor and an external power source; The first fixed end is connected in series to the Tip signal line, the second fixed end is connected in series to the Ring signal line, the first free end is connected to the voltage reference circuit, and the second free end is connected in series to the SLIC_Tip signal line, the third The free end is connected in series to the SLIC_Ring signal line, and the fourth free end is grounded. The electronic device of claim 18, wherein the reference voltage circuit comprises: a second diode having an anode receiving a sixth reference voltage; a tenth resistor connected to the cathode of the second diode and the Between the first free ends of the double pole double throw switch. The electronic device of claim 11, wherein the alarm circuit comprises: a second transistor having a base connected to an output end of the second logic element and an emitter grounded; the eleventh resistor connected to a base of the second transistor and an output of the second logic element; a twelfth resistor; a capacitor connected in parallel with the twelfth resistor between the base of the second transistor and the ground; a speaker respectively connected to the base and the external power source of the second transistor; and a thirteenth resistor connected between the external power source and the speaker.