CN-122018404-A - Isolation switch value acquisition circuit

CN122018404ACN 122018404 ACN122018404 ACN 122018404ACN-122018404-A

Abstract

The application belongs to the technical field of rail transit signal control, and particularly relates to an isolation switch value acquisition circuit which comprises a clock source circuit, an excitation source circuit, a primary amplifying circuit, a secondary amplifying circuit and a tertiary output circuit which are sequentially cascaded. The clock source circuit outputs square wave signals to a field effect transistor in the excitation source circuit, drives a primary excitation signal generated by the first transformer, and sequentially couples and amplifies the primary excitation signal with a corresponding transformer through the first, second and third triodes, wherein the primary amplification circuit modulates an externally input differential switching value signal into an excitation chain, and finally the fourth transformer outputs an isolated differential switching value signal. According to the application, by constructing a complete dynamic excitation signal chain, the output effectiveness is completely dependent on the continuous transmission of the chain, so that the protection mechanism of automatic guiding of the output to the safety side in the event of any critical device failure is realized, and meanwhile, the anti-interference capability and the driving capability of signals are obviously improved through the coupling and amplification of a multi-stage transformer.

Inventors

PAN DEMIN
GAI MENG
LI GUOBIN

Assignees

中车青岛四方车辆研究所有限公司

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (10)

1. An isolated switching value acquisition circuit, comprising: A clock source circuit configured to output a periodic square wave voltage signal; an excitation source circuit comprising a field effect transistor and a first transformer configured to generate a primary high frequency switch excitation signal from the periodic square wave voltage signal; The grid electrode of the field effect tube is connected with the output end of the clock source circuit, and the source electrode of the field effect tube is connected with a reference ground power supply; The first-stage amplifying circuit comprises a first triode and a second transformer; The base electrode of the first triode is connected with the secondary side positive electrode of the first transformer, and the emitter electrode of the first triode and the secondary side negative electrode of the first transformer are commonly connected with a switching value negative phase signal to be collected; The second-stage amplifying circuit comprises a second triode and a third transformer; The base electrode of the second triode is connected with the secondary side positive electrode of the second transformer, and the emitter electrode of the second triode and the secondary side negative electrode of the second transformer are commonly connected with the reference ground power supply; the three-stage output circuit comprises a third triode and a fourth transformer; The base electrode of the third triode is connected with the secondary side positive electrode of the third transformer, the emitter electrode of the third triode and the secondary side negative electrode of the third transformer are connected with the reference ground power supply together, the primary side negative electrode of the fourth transformer is connected with the collector electrode of the third triode, the primary side positive electrode of the fourth transformer is connected with the input power supply, the secondary side homonymous end of the fourth transformer outputs the switching value positive phase signal, and the secondary side heteronymous end of the fourth transformer outputs the switching value negative phase signal.
2. The isolated switching value acquisition circuit according to claim 1, wherein the excitation source circuit includes: the first end of the first current limiting resistor is connected with the input power supply, and the second end of the first current limiting resistor is connected with the primary side positive electrode of the first transformer; and the first end of the second current limiting resistor is connected with the reference ground power supply, and the second end of the second current limiting resistor is connected with the source stage of the field effect transistor.
3. The isolated switching value acquisition circuit according to claim 2, wherein the primary amplifying circuit includes: The first end of the third current limiting resistor is connected with a switching value positive phase signal to be acquired, and the second end of the third current limiting resistor is connected with the primary side positive pole of the second transformer; The first end of the fourth current limiting resistor is connected with a switching value negative phase signal to be collected, and the second end of the fourth current limiting resistor is connected with the emitter of the first triode and the secondary side negative electrode of the first transformer; the resistance value of the third current limiting resistor is smaller than that of the first current limiting resistor; the resistance value of the fourth current limiting resistor is smaller than that of the second current limiting resistor.
4. The isolated switching value acquisition circuit according to claim 3, wherein the secondary amplification circuit comprises: The first end of the fifth current limiting resistor is connected with the input power supply, and the second end of the fifth current limiting resistor is connected with the primary side positive electrode of the third transformer; the resistance value of the fifth current limiting resistor is smaller than that of the third current limiting resistor.
5. The isolated switching value acquisition circuit of claim 1, wherein the primary amplifying circuit comprises: The first voltage division protection resistor is connected with the base electrode of the first triode, and the second end of the first voltage division protection resistor is connected with the positive electrode of the secondary side of the first transformer.
6. The isolated switching value collection circuit of claim 5, wherein the secondary amplification circuit comprises: The first end of the second voltage division protection resistor is connected with the base electrode of the second triode, and the second end of the second voltage division protection resistor is connected with the positive electrode of the secondary side of the second transformer; the resistance value of the second voltage division protection resistor is smaller than that of the first voltage division protection resistor.
7. The isolated switching value acquisition circuit of claim 6, wherein the three-stage output circuit comprises: the first end of the third voltage division protection resistor is connected with the base electrode of the third triode, and the second end of the third voltage division protection resistor is connected with the positive electrode of the secondary side of the third transformer; And the resistance value of the third voltage division protection resistor is smaller than that of the second voltage division protection resistor.
8. The isolated switching value acquisition circuit of claim 1, further comprising: The negative electrode of the first diode is connected with the second end of the first current limiting resistor; The positive electrode of the first voltage stabilizing tube is connected with the positive electrode of the first diode, and the negative electrode of the first voltage stabilizing tube is connected with the primary side negative electrode of the first transformer; the negative electrode of the second diode is connected with the second end of the third current limiting resistor; the positive electrode of the second voltage stabilizing tube is connected with the positive electrode of the second diode, and the negative electrode of the second voltage stabilizing tube is connected with the primary side negative electrode of the second transformer; The negative electrode of the third diode is connected with the second end of the fifth current limiting resistor; The positive electrode of the third voltage stabilizing tube is connected with the positive electrode of the third diode, and the negative electrode of the third voltage stabilizing tube is connected with the primary side negative electrode of the third transformer; The cathode of the fourth diode is connected with the input power supply; and the anode of the fourth voltage stabilizing tube is connected with the anode of the fourth diode, and the cathode of the fourth voltage stabilizing tube is connected with the primary side cathode of the fourth transformer.
9. The isolated switching value acquisition circuit of claim 1, further comprising: the positive electrode of the fifth diode is connected with the same-name end of the secondary side of the fourth transformer; and the anode of the first filter capacitor is connected with the cathode of the fifth diode, and the cathode of the first filter capacitor is connected with the center tap of the fourth transformer.
10. The isolated switching value acquisition circuit of claim 1, further comprising: The negative electrode of the sixth diode is connected with the secondary side synonym end of the fourth transformer; And the anode of the second filter capacitor is connected with the center tap of the fourth transformer, and the cathode of the second filter capacitor is connected with the anode of the sixth diode.

Description

Isolation switch value acquisition circuit Technical Field The application belongs to the technical field of rail transit signal control, and particularly relates to an isolating switch value acquisition circuit. Background In a network control system of a high-speed train such as a maglev train, a vehicle-mounted controller needs to collect a large amount of switching value signals (such as a safety interlocking state and equipment feedback signals) in real time. These signals tend to be generated in harsh environments with strong electromagnetic interference and require extremely high levels of safety integrity for the system. The switching value acquisition scheme commonly adopted at present is mostly realized based on a photoelectric isolator. Such schemes, while capable of electrical isolation, have uncontrollable failure modes. For example, when an optocoupler or associated protection device fails, the output may be fixed at a high or low level, rather than being directed to a safe, no-signal state, which presents a safety hazard in high safety-required application scenarios. In addition, the signal driving capability of the scheme is limited, and the anti-interference capability is easily affected when long-distance transmission is performed. Therefore, there is a need for an isolation switch amount collection scheme that can ensure reliable guiding to the safety side in the event of failure of any single component, and that has a strong anti-interference capability. Disclosure of Invention The invention solves the technical problems at least to a certain extent, and provides the isolation switching value acquisition circuit, which realizes that when any key device breaks down, an output signal can be automatically and reliably guided to a safe side by constructing a multistage transformer coupling dynamic excitation chain driven by a clock source, and simultaneously improves the anti-interference capability and the driving capability of signal transmission. The embodiment of the disclosure provides an isolation switch value acquisition circuit, which is characterized by comprising: A clock source circuit configured to output a periodic square wave voltage signal; an excitation source circuit comprising a field effect transistor and a first transformer configured to generate a primary high frequency switch excitation signal from the periodic square wave voltage signal; The grid electrode of the field effect tube is connected with the output end of the clock source circuit, and the source electrode of the field effect tube is connected with a reference ground power supply; The first-stage amplifying circuit comprises a first triode and a second transformer; The base electrode of the first triode is connected with the secondary side positive electrode of the first transformer, and the emitter electrode of the first triode and the secondary side negative electrode of the first transformer are commonly connected with a switching value negative phase signal to be collected; The second-stage amplifying circuit comprises a second triode and a third transformer; The base electrode of the second triode is connected with the secondary side positive electrode of the second transformer, and the emitter electrode of the second triode and the secondary side negative electrode of the second transformer are commonly connected with the reference ground power supply; the three-stage output circuit comprises a third triode and a fourth transformer; The base electrode of the third triode is connected with the secondary side positive electrode of the third transformer, the emitter electrode of the third triode and the secondary side negative electrode of the third transformer are connected with the reference ground power supply together, the primary side negative electrode of the fourth transformer is connected with the collector electrode of the third triode, the primary side positive electrode of the fourth transformer is connected with the input power supply, the secondary side homonymous end of the fourth transformer outputs the switching value positive phase signal, and the secondary side heteronymous end of the fourth transformer outputs the switching value negative phase signal. The technical scheme provided by the application has the following beneficial effects that the effectiveness of an output signal is completely dependent on the smoothness of a complete dynamic excitation signal chain driven by a clock source and coupled through a multi-stage transformer. When any component in the chain breaks down, the transmission of the excitation signal is interrupted, and the final output automatically changes into a state without effective signals, so that global fault guiding safety is realized, and the safety and integrity level of the system are greatly improved. In other embodiments of the present application, the excitation source circuit includes: the first end of the first current limiting resistor is connected