Passive mining telephone double-loop protection communication circuit

Abstract

A passive mining telephone double-loop protection communication circuit disclosed by the present invention comprises a switching circuit, a working circuit and a conditioning circuit, the switching circuit comprises an external connection end, a wiring end used for being connected with the conditioning circuit and the working circuit and a relay used for being in communication connection with an MCU, and the external connection end comprises a main interface and a standby interface. A double-pole-double-throw switch is arranged between the wiring end and the external connection end. The device is simple in structure, has a double-loop circuit, and ensures safe and reliable communication.

Description

TECHNICAL FIELD

[0001] The application relates to a passive mine telephone double-circuit protection communication circuit. BACKGROUND

[0002] The passive mine telephone is a communication equipment specially designed for an environment with explosive gas (methane, coal dust) such as a coal mine, does not need a local power supply (energy is provided by a remote end in a well), adopts an intrinsically safe design, converts voice into optical signals or adaptive electrical signals through a passive technology (or a safety coupler matched signal) such as a fiber microphone, and realizes voice communication between a well and a well dispatching room, has anti-interference and explosion-proof characteristics, can provide a voice channel for an emergency situation (such as power failure) in the well under the condition of no battery power supply, assists in rescue positioning and disaster transmission, guarantees communication and emergency requirements of miners, and is often matched with a program-controlled dispatching switch and the like to form a stable mine communication system. The existing program-controlled dispatching equipment does not have a line routine detection function, cannot predict the telephone line state, and the existing telephone is basically a single-line telephone, is difficult to switch, has a high cost, and is difficult to control and identify. SUMMARY

[0003] In view of the defects of the prior art, the application provides a passive mine telephone double-circuit protection communication circuit which is simple in structure, has a double-circuit, and guarantees safe and reliable communication.

[0004] To achieve the above object, the application provides a passive mine telephone double-circuit protection communication circuit which comprises a switching circuit, a working circuit and a conditioning circuit, the switching circuit comprises an external terminal, a wiring terminal for being connected with the conditioning circuit and the working circuit, and a relay for being connected with an MCU, the external terminal comprises a main interface and a standby interface, and a double-pole double-throw switch is arranged between the wiring terminal and the external terminal.

[0005] As a further arrangement of the application, the conditioning circuit is provided with a plurality of conditioning lines, the conditioning lines comprise a coupling capacitor and a voltage dividing resistor connected in sequence, and one of the conditioning lines is further connected with a first power supply.

[0006] As a further arrangement of the application, the working circuit comprises a protection module, an indication module, a signal amplification module and a filter module, the protection module comprises a bridge diode group, a voltage stabilizing tube, an anti-reverse diode and a current limiting resistor.

[0007] As a further arrangement of the application, the indication module comprises a driving link composed of a second power supply, an isolation diode, a driving triode, a switching triode and a state indicating lamp.

[0008] The beneficial effects of such an arrangement are: such an arrangement, through the combination of switching circuit, working circuit and conditioning circuit, realizes two-way voice transmission (handset / line-to-line voice transmission), power and signal protection (against mine surge, reverse connection), state indication (call / standby lamp display), meets the mine requirements, supports clear and stable underground communication, the switching circuit can change the signal path by attracting the contacts of the relay JQ1 coil (RL+, LL+ power supply), so that when one path is interrupted, the standby path can be switched to continue to use, at the same time, through the conditioning circuit, cooperate with the coupling capacitor, "pass AC, isolate DC", block the influence of DC voltage before and after the stage, only transmit the voice AC component, through the voltage dividing resistor, realize voltage dividing and matching, through the resistance ratio adjustment signal amplitude, make the later stage circuit work in the best interval, at the same time, it can also limit the current for explosion prevention, effectively limit the current when fault, ensure that the circuit energy is not enough to ignite gas or coal dust, the first power supply is set as DC bias and power supply, provides a stable DC operating point for the signal (makes the transistor of the later stage amplification circuit in "conducting-amplification" state), avoids distortion of voice signal due to circuit cutoff / saturation, through the conditioning circuit, ensures clear and clear voice signal, ensures mine communication; the working circuit includes multiple modules, through the protection module, when normal power supply, the current path is from the line power (or handset power supply) to the BT1P / BRING interface, then to the bridge diode group, two of which are forward conducting, the other two are reverse cut-off, after passing through the current limiting resistor, finally through the reverse breakdown of the voltage stabilizing tube to the later stage circuit, the half-bridge bridge diode group only allows forward current to pass through, and the voltage stabilizing tube breaks down to clamp the voltage at a stable value, providing a safe voltage for the later stage circuit, when the current is reversed, the current is guided to the ground by the other half of the bridge diode group, blocking the power supply of the later stage circuit, avoiding damage to components due to reverse voltage; when surge interference occurs, the surge voltage is guided to the ground by the bridge diode group, at the same time, through the current limiting resistor for current limiting, and stabilized by the voltage stabilizing tube, ensuring that the voltage after surge is still stable, not affecting the work of the later stage, finally realizing "no matter the power supply is reversed or the line is surging, the later stage circuit can work safely", making the communication equipment stable and reliable in dangerous environment.The signal amplification module and the filter module are conventional settings in the telephone circuit, and will not be described again. The further indication module, in operation, an external line ring high voltage pulse, through the current limiting and voltage stabilizing of the power protection module, triggers the front stage circuit, the second power supply flows to the isolation diode through the resistance on the line and supplies power to the base of the driving transistor, and the ring pulse is used as a trigger signal to open the base path of the driving transistor, changing from the cut-off state to the conduction state; when the driving transistor drives the switching transistor, the second power supply reaches the base of the switching transistor through the driving transistor emitter and the isolation diode, so that the base of the switching transistor is provided with a bias current after the driving transistor is turned on, thereby opening the power supply loop of the state indicator lamp, so that the state indicator lamp forms a path from the second power supply to the state indicator lamp to the switching transistor and finally to the ground, so that the state indicator lamp is lit. At the same time, if in the process of calling, the current change of the rear stage amplification circuit triggers the voltage fluctuation of the base of the driving transistor, the switching transistor can also be temporarily turned on, and the state indicator lamp flashes or is always bright, prompting that the equipment is in the calling state, which assists in troubleshooting. BRIEF DESCRIPTION OF DRAWINGS

[0009] Fig. 1 The circuit diagram of the switching circuit in the embodiment of the application;

[0010] Fig. 2 The circuit diagram of the conditioning circuit in the embodiment of the application;

[0011] Fig. 3 The circuit diagram of the working circuit in the embodiment of the application. DETAILED DESCRIPTION

[0012] The application provides an embodiment of a passive mine telephone double-circuit protection communication circuit, as shown in the figure, which comprises a switching circuit, a working circuit and a conditioning circuit. Figs. 1 to 3 The switching circuit comprises an external terminal, a wiring terminal for connecting with the conditioning circuit and the working circuit and a relay for communicating with the MCU, the external terminal comprises a main interface and a backup interface, and a double-pole double-throw switch is arranged between the wiring terminal and the external terminal. The conditioning circuit is provided with a plurality of conditioning lines, and the conditioning line comprises a coupling capacitor and a voltage dividing resistor connected in sequence, and one of the conditioning lines is further connected with a first power supply. The working circuit comprises a protection module, an indication module, a signal amplification module and a filter module, the protection module comprises a bridge diode group, a voltage stabilizing tube, an anti-reverse diode and a current limiting resistor. The indication module comprises a driving link composed of a second power supply, an isolation diode, a driving transistor, a switching transistor and a state indicator lamp.

[0013] Fig. 1For switching circuit, including relay (JQ1): core switching components, through the coil control contacts, select which way signal (ATIP / BTIP / ARING / BRING) on; current limiting resistor (R18, R19): in series in RL+, LL+ loop, limit signal current; RL+, LL+: connect relay coil power, control JQ1 action; standby / handle talk state (coil not energized), contact position: JQ1 contact on BTIP, BRING; signal path: handle voice→BTIP / BRING→JQ1 contact→internal module (such as amplifier circuit); function: after the phone is taken off hook, default use "handle-internal module" link, realize local talk test or short distance communication; external line talk state (coil energized and attracted), trigger condition: dial or dispatch station instruction→RL+, LL+ energized→JQ1 coil attracted, contact position: switch to ATIP, ARING, signal path: mine external line→AA / BB→JQ1 contact→ATIP / ARING→internal module→handle; function: connect mine communication bus, realize underground-overground / cross area communication.

[0014] Fig. 2For conditioning circuit circuit diagram, wherein C45, C66, C128 is coupled capacitor, C8 is filter capacitor, R115, R157, R158, R160, R177 is voltage dividing resistor, 1VDD is the first power supply, C45 is connected in series in the ATIP→ post stage (ARINGIN) path; C66 is connected in series in the ARING→ post stage (ATIPIN) path; C128 is connected in series in the ARING→ post stage (ARINGIN) path. Utilize the capacitor "pass AC, DC isolation" characteristics, block the DC interference in the telephone line (such as remote power supply, circuit bias voltage), only let the voice AC signal (300-3400Hz) pass through, avoid the mutual influence of the front and rear stage DC voltage. R115 is a voltage dividing resistor, one end of which is connected to the common node of C45 / C66, and the other end is connected to R160; R157 is connected in series in the ATIP→ARINGIN path (C45 post stage); R158 is connected in series in the ARING→ATIPIN path (C66 post stage); R160 is connected in series in the R115→1VDD path (provides DC bias); R177 is connected in series in the ARING→ARINGIN path (C128 post stage); C8 is connected in parallel in the R158 post stage of the ARING→ATIPIN path, one end of which is connected to the signal line and the other end is connected to the ground (GND); filter the high frequency noise in the voice signal (such as mine motor spark, electromagnetic interference high frequency component, usually >10kHz). The high frequency signal has small capacity resistance, and C8 can "short circuit" it to the ground, retaining the 300-3400Hz voice effective frequency band and improving the call clarity; 1VDD (stable DC power supply, such as 1.8V) is connected to R115 through R160, providing DC bias voltage for the signal path. Provide a stable DC operating point for the post-amplification / detection circuit (such as a triode, a comparator). The voice signal is an AC signal superimposed on a DC bias for transmission, which can ensure that the active device in the post stage works in the "linear amplification zone" to avoid signal distortion due to device cutoff / saturation. 1VDD (stable DC power supply, such as 1.8V) is connected to R115 through R160, providing DC bias voltage for the signal path.

[0015] The working circuit comprises a protection module, an indication module, a signal amplification module and a filter module, the protection module comprises a bridge diode group, a voltage stabilizing tube, an anti-reverse diode and a current limiting resistor.

[0016] Fig. 3For the working circuit circuit diagram, the protection module includes D5 (anti-reverse diode), D9-D15 (bridge diode group), Z2 (voltage stabilizing tube), R8 / R40 (current limiting resistor); signal amplification module, including Q2 / Q4 / Q6 / Q7 / Q8 / Q9 (triode), R20 / R21 / R30 (resistor); indication module, Q1 (switching triode), LED6 (state indicating lamp), D6 (isolating diode); filter module includes C2 / C5 / C7 / C9 / C14 (capacitor), 1VDD / 2VDD (power supply);

[0017] D9-D15 form a bridge diode: D9 / D11 is the upper bridge arm, D10 / D15 is the lower bridge arm, and is cross-connected with BT1P / BR1NG; Z2 (voltage stabilizing tube) is connected in anti-parallel at the bridge output end, the cathode is connected with R40, and the anode is connected with the ground; R8 / R40 (current limiting resistor) is connected in series in the power supply path, R8 is connected with D5, and R40 is connected with the bridge output. When normally powered: BT1P→D9 (positive→negative)→R40→Z2 (negative→positive, voltage stabilization)→the latter stage; when reverse connection protection: BR1NG→D10 (negative→positive)→R40→Z2→ground (block the reverse pressure of the latter stage); surge protection: D9-D15 full-bridge conduction discharges the surge, R8 / R40 limits the current, and Z2 stabilizes the voltage.

[0018] Q7-Q9 form a preamplification stage: Q7 base is connected with 2HOLD (control signal), Q8 / Q9 form a complementary amplifier, and R27 / R28 are bias resistors; Q2 / Q4 / Q6 form a power amplification stage: Q6 base is connected with the preamplification output, Q2 / Q4 form a push-pull drive, and R20 / R21 are load matching resistors. The signal path is: voice input (BT1P)→bridge protection→preamplification (Q7 conduction→Q8 / Q9 amplification)→power amplification (Q6 drive→Q2 / Q4 push-pull)→loudspeaker (BR1NG side).

[0019] In the indication module, Q1 (switching triode) base is connected with Q4 emitter, collector is connected with LED6, and emitter is connected with the ground; D6 (isolating diode) anode is connected with 2VDD, and cathode is connected with Q4 base; LED6 is connected with R16 in series for current limiting, and is connected with BVDD power supply. The signal path is: ringing trigger: external ringing→2VDD→D6→Q4 base→Q4 conduction→Q1 base bias→Q1 conduction→LED6 lighting (ringing prompt).

[0020] In the filter module, C2 / C14 are connected in parallel at the BVDD / 2VDD power supply end (filtering power supply noise); C5 / C7 / C9 are connected in series in the signal path (direct current isolation and high-frequency noise filtering); 1VDD / 2VDD provides direct current bias for the triode (ensures linear operation of the amplification circuit).

[0021] The above examples are only one of the preferred embodiments of the present application, and the usual changes and replacements made by the person skilled in the art within the technical scheme of the present application are included in the protection scope of the present application.

Claims

1. A passive mining telephone dual-circuit protection communication circuit, including a switching circuit, a working circuit and a conditioning circuit, characterized in that: The switching circuit includes an external terminal, a connection terminal for connecting to the conditioning circuit and the working circuit, and a relay for communicating with the MCU. The external terminal includes a main interface and a backup interface. A double-pole double-throw switch is provided between the connection terminal and the external terminal.

2. The passive mining telephone dual-circuit protection communication circuit according to claim 1 is characterized in that: The conditioning circuit is provided with a plurality of conditioning circuits, and the conditioning circuits include coupling capacitors and voltage-dividing resistors connected in sequence, wherein one of the conditioning circuits is further connected to a first power supply.

3. The passive mining telephone dual-circuit protection communication circuit according to claim 1 is characterized in that: The working circuit includes a protection module, an indication module, a signal amplification module and a filtering module. The protection module includes a bridge diode group, a voltage regulator tube, an anti-reverse connection diode and a current limiting resistor.

4. The passive mining telephone dual-circuit protection communication circuit according to claim 3 is characterized in that: The indication module is composed of a driving link consisting of a second power supply, an isolation diode, a driving transistor, a switching transistor and a status indicator light.

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