Isolation circuit for level conversion

Abstract

The utility model discloses an isolation circuit for level conversion. The isolation circuit comprises an isolation power supply, a first level conversion module, a second level conversion module and a digital isolator, the isolation power supply is unidirectionally and electrically connected with the first level conversion module and the second level conversion module; the first level conversion module and the second level conversion module are connected with the digital isolator; according to the utility model, electrical isolation between modules can be maintained, electrical connection between input signals and output signals can be isolated, more stable signal conversion and transmission can be realized in an electrical isolator state, and meanwhile, the isolation power supply can convert input voltage into another voltage, so that the conversion efficiency is improved. According to the utility model, electrical isolation and safety protection among different voltage domains can be provided, and when the first level conversion module, the second level conversion module and the digital isolator need a power supply to supply power, the influence of electrical interference signals is not easily caused, so that the reliability and stability of the circuit are ensured.

Description

Technical Field

[0001] The utility model relates to the field of isolation circuits, in particular to an isolation circuit for level conversion. Background Art

[0002] The serial port, also known as the serial communication interface, is a commonly used interface in personal computers. Serial communication requires both parties to use a standard interface, allowing different devices to easily connect and communicate. The standard serial interface uses a DB-9 connector and has nine signals. In the automation field, only the RXD, TXD, and GND lines are generally used. This is a very common interface, facilitating device debugging and short-distance communication between devices.

[0003] Although the existing technology has improved the anti-interference ability in the use of serial port circuits, it is still affected by the environment and multiple other elements, which causes the input voltage and output voltage of the system to become very unstable. In addition, there is also electrical interference between the output signal and the input signal, making the circuit very susceptible to damage. Therefore, an isolation circuit with better isolation performance is urgently needed. Utility Model Content

[0004] The utility model provides an isolation circuit for level conversion, which can improve the isolation performance of the circuit.

[0005] In order to solve the above technical problems, the utility model provides an isolation circuit for level conversion, comprising: an isolation power supply, a first level conversion module, a second level conversion module and a digital isolator;

[0006] Wherein, the isolated power supply is unidirectionally electrically connected to the first level conversion module and the second level conversion module;

[0007] The first level conversion module and the second level conversion module are connected to the digital isolator;

[0008] The digital isolator includes a first digital isolator and a second digital isolator; wherein the first digital isolator is used to connect to the first level conversion module; the second digital isolator is used to connect to the second level conversion module;

[0009] The first digital isolator and the second digital isolator both include: a digital isolation chip;

[0010] The first power port of the digital isolation chip is connected to the power supply voltage; the second power port of the digital isolation chip is connected to the isolated power supply voltage;

[0011] The first digital isolator and the second digital isolator both further include: a third capacitor and a fourth capacitor;

[0012] The first power supply ports of the digital isolation chips of the first digital isolator and the second digital isolator are grounded through a third capacitor; the second power supply ports of the digital isolation chips of the first digital isolator and the second digital isolator are grounded through a fourth capacitor.

[0013] The level conversion isolation circuit of the present invention includes an isolated power supply, a first level conversion module, a second level conversion module and a digital isolator, which can maintain electrical isolation between modules, avoid interference between modules, and isolate the electrical connection between input signals and output signals. In the electrical isolator state, more stable signal conversion and transmission are achieved. At the same time, the isolated power supply can convert the input voltage into another voltage, so that the utility model can provide electrical isolation and safety protection between different voltage domains. When the first level conversion module, the second level conversion module and the digital isolator need power supply, they are not easily affected by electrical interference signals, thereby ensuring the reliability and stability of the circuit.

[0014] As a preferred solution, the isolated power supply includes an output device;

[0015] The output device is unidirectionally electrically connected to the first level conversion module and the second level conversion module;

[0016] The output device is used to output an isolated power supply voltage.

[0017] As a preferred solution, the level conversion isolation circuit further includes a main control chip; the main control chip is used to connect to the digital isolator.

[0018] As a preferred solution, the isolation circuit for level conversion further includes an external interface; the external interface is used to connect with the first level conversion module and the second level conversion module.

[0019] The digital isolation chip is a chip with model number Π122U31.

[0020] As a preferred solution, the first level conversion module includes: a first level conversion chip and a plurality of TVS tubes;

[0021] The first port to the fourth port of the first level conversion chip are grounded through a TVS tube.

[0022] The model of the first level conversion chip is TPT3232E-SO3R.

[0023] As a preferred solution, the second level conversion module includes: a second level conversion chip, an amplifier circuit and an electrostatic diode;

[0024] An enable port of the second level conversion chip is connected to the amplifier circuit; and an output port of the second level conversion chip is connected to the electrostatic diode.

[0025] As a preferred solution, the model of the second level conversion chip is TP8485E-SR.

[0026] As a preferred solution, the isolated power supply uses a chip with model number B0303S-1WR3. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural diagram of an embodiment of a level conversion isolation circuit provided by the utility model;

[0028] Figure 2 This is a structural diagram of another embodiment of the level conversion isolation circuit provided by the utility model;

[0029] Figure 3 This is a circuit diagram of an embodiment of the isolated power supply provided by the utility model;

[0030] Figure 4 This is a circuit diagram of an embodiment of the digital isolator provided by the present utility model;

[0031] Figure 5 This is a circuit diagram of an embodiment of the first level conversion module provided by the present utility model;

[0032] Figure 6 This is a circuit diagram of an embodiment of the second level conversion module provided by the present utility model. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Although the existing technology has improved the anti-interference ability in the use of serial port circuits, it is still affected by the environment and multiple other elements, which causes the input voltage and output voltage of the system to become very unstable. In addition, there is also electrical interference between the output signal and the input signal, making the circuit very susceptible to damage. Therefore, an isolation circuit with better isolation performance is urgently needed.

[0035] Example 1

[0036] In order to solve the above technical problems, the utility model provides an isolation circuit for level conversion, which can improve the isolation performance of the circuit.

[0037] See also Figure 1 and Figure 2 , Figure 1 This is a structural diagram of an embodiment of a level conversion isolation circuit provided by the utility model; Figure 2 It is a structural diagram of another embodiment of the level conversion isolation circuit provided by the utility model.

[0038] like Figure 1 As shown, the isolation circuit for level conversion includes: an isolated power supply 1, a first level conversion module 2, a second level conversion module 3 and a digital isolator 4;

[0039] The isolated power supply 1 is electrically connected to the first level conversion module 2 and the second level conversion module 3 in a unidirectional manner;

[0040] The first level conversion module 2 and the second level conversion module 3 are connected to the digital isolator 4 .

[0041] See below Figure 3 , Figure 3 This is a circuit diagram of an embodiment of the isolated power supply provided by the utility model.

[0042] like Figure 3 As shown, the isolated power supply 1 includes an isolated power supply chip, several capacitors and several resistors;

[0043] Among them, the power port of the isolated power supply chip is connected to the power supply voltage, and the output port of the isolated power supply chip outputs the isolated power supply voltage 3.3V_ISO and is grounded through capacitors and several resistors; specifically, the power port of the isolated power supply chip is connected to the power supply voltage and is grounded through the first capacitor C123, and the output port of the isolated power supply chip outputs the isolated power supply voltage 3.3V_ISO and is grounded through the second capacitor C122 and the first resistor R143.

[0044] Furthermore, the isolated power supply 1 uses a chip with model number B0303S-1WR3.

[0045] In this embodiment, the isolated power supply is used to regulate, convert and isolate the input voltage and the output voltage.

[0046] In this embodiment, the isolated power supply is a module based on the conversion principle, which can convert one voltage into another voltage and realize the isolation and filtering of electrical signals at the same time; the core component of the isolated power supply is the switching circuit, and its working principle is based on the synergy of the switching tube and the controller to realize the conversion and isolation between the input voltage and the output voltage, so that the VCC power supply of other modules is not easily affected by interference factors, thereby protecting the circuit; the isolated power supply can realize precise adjustment and protection of the output voltage through the effective control and adjustment of the control chip, providing electrical isolation and safety protection between different voltage domains.

[0047] In this embodiment, the isolated power supply can prevent current interference and electrical shock, ensure the safety and reliability of the circuit, filter input deformation and electromagnetic interference, and reduce output ripple, making the output voltage and current more stable.

[0048] Furthermore, if Figure 2 As shown, the isolated power supply 1 includes an output device 11;

[0049] The output device 11 is unidirectionally electrically connected to the first level conversion module 2 and the second level conversion module 3;

[0050] The output device 11 is used to output an isolated power supply voltage 3.3V_ISO.

[0051] Furthermore, if Figure 2 As shown, the level conversion isolation circuit further includes a main control chip 5 ; the main control chip 5 is used to connect with the digital isolator 4 .

[0052] Furthermore, if Figure 2 As shown, the isolation circuit for level conversion further includes an external interface 6 ; the external interface 6 is used to connect with the first level conversion module 2 and the second level conversion module 3 .

[0053] Furthermore, if Figure 2 As shown, the digital isolator 4 includes a first digital isolator 41 and a second digital isolator 42;

[0054] The first digital isolator 41 is used to connect to the first level conversion module 2 ; the second digital isolator 42 is used to connect to the second level conversion module 3 .

[0055] In this embodiment, the digital isolator can realize digital signal transmission in an electrical isolator state.

[0056] In this embodiment, the first digital isolator and the second digital isolator both isolate the electrical connection between the input signal and the output signal to achieve signal transmission and isolation.

[0057] See below Figure 4 , Figure 4 This is a circuit diagram of an embodiment of the digital isolator provided by the utility model.

[0058] Figure 4 The first digital isolator 41 and the second digital isolator 42 are included in the circuit.

[0059] Further, if Figure 4 As shown, the first digital isolator and the second digital isolator both include: a digital isolation chip U5;

[0060] The first power port of the digital isolation chip U5 is connected to the power supply voltage; the second power port of the digital isolation chip U5 is connected to the isolated power supply voltage 3.3V_ISO.

[0061] In this embodiment, the first digital isolator and the second digital isolator both further include: a plurality of capacitors;

[0062] The power supply ports of the digital isolation chips of the first digital isolator and the second digital isolator are both grounded through capacitors;

[0063] The input ports of the digital isolation chip U5 of the first digital isolator and the second digital isolator are connected to the serial port of the main control chip and receive signals output by the serial port of the main control chip.

[0064] Specifically, if Figure 4 As shown, the first power supply port of the digital isolation chip U5 of the first digital isolator and the second digital isolator is connected to the power supply voltage and grounded through the third capacitor C42, and the second power supply port of the digital isolation chip U5 of the first digital isolator and the second digital isolator is connected to the isolated power supply voltage 3.3V_ISO and grounded through the fourth capacitor C43.

[0065] Furthermore, the digital isolation chip is a chip with model number Π122U31.

[0066] In this embodiment, the digital isolation chip utilizes the principle of a capacitive voltage divider to transmit voltage signals directly through the isolator capacitor without signal modulation and demodulation. The characteristics of the capacitor are utilized to transfer the signal from one circuit to another. At the same time, the capacitor has a high impedance characteristic, which can effectively reduce the impact of electrical noise while also maintaining electrical isolation between the two circuits, thereby avoiding mutual interference between the circuits. The digital isolator can effectively isolate the electrical interference between the input and output signals of the first level conversion module and the second level conversion module, respectively, and reduce the noise of the ground loop, isolate the ground loop between the two circuits or modules, and block the propagation of interference signals such as common mode and surge, thereby more stably and efficiently converting the received serial port TTL signal into another level, such as RS-485 level or RS-232 level, through the first level conversion module and the second level conversion module.

[0067] See below Figure 5 , Figure 5 This is a circuit diagram of an embodiment of the first level conversion module provided by the present utility model.

[0068] Furthermore, if Figure 5 As shown, the first level conversion module 2 includes: a first level conversion chip U14 and several TVS tubes;

[0069] The first port to the fourth port of the first level conversion chip U14 are grounded through a TVS tube.

[0070] Specifically, if Figure 5 As shown, the first port to the fourth port of the first level conversion chip U14 are grounded through the first TVS tube D30, the second TVS tube D31, the third TVS tube D32 and the fourth TVS tube D33 respectively.

[0071] Furthermore, the model of the first level conversion chip U14 is TPT3232E-SO3R.

[0072] In this embodiment, the first level conversion module based on the first level conversion chip with the chip model being TPT3232E-SO3R realizes bidirectional communication through two sending channels and two receiving channels of the serial port.

[0073] In this embodiment, the first level conversion module realizes bidirectional communication by two-way sending and two-way receiving of the serial port. By setting the first level conversion chip, the mutual conversion between the serial port TTL level and the RS-232 level logic is realized, and the TTL signal of the serial port is converted into a level signal. Moreover, the range of the level signal is larger, thereby improving the anti-interference ability.

[0074] See below Figure 6 , Figure 6This is a circuit diagram of an embodiment of the second level conversion module provided by the present utility model.

[0075] Furthermore, if Figure 6 As shown, the second level conversion module 3 includes: a second level conversion chip U13, an amplifier circuit and an electrostatic diode D29;

[0076] The enable port of the second level conversion chip U13 is connected to the amplifier circuit; the output port of the second level conversion chip U13 is connected to the electrostatic diode D29.

[0077] Furthermore, the model of the second level conversion chip U13 is TP8485E-SR.

[0078] In this embodiment, the model of the electrostatic diode D29 may be, but is not limited to, SM712.

[0079] Specifically, if Figure 6 As shown, the enable port of the second level conversion chip U13 includes an RE port and a DE port; the amplifier circuit includes a second resistor R160, a third resistor R155 and a transistor Q10; wherein, the first end of the second resistor R160 is connected to the first end of the transistor Q10, the second end of the third resistor R155 is connected to the third end of the transistor Q10, the first end of the third resistor R155 is connected to the isolated power supply voltage 3.3V_ISO, the second end of the second resistor R160 and the second end of the transistor Q10 are grounded, and the third end of the transistor Q10 is used to connect to the enable port of the second level conversion chip U13.

[0080] In this embodiment, the second level conversion module based on the second level conversion chip with the chip model being TP8485E-SR is used to convert the serial port input signal into a differential signal, and implement communication using a balanced transmission and differential reception method.

[0081] In this embodiment, the second level conversion chip of the second level conversion module converts the serial port input signal into a differential signal, adopts balanced transmission and differential reception to achieve communication, realizes the conversion between the serial port TTL level and the RS-485 level logic, converts the serial data into a differential signal and performs modulation and demodulation, thereby increasing the anti-interference capability of the communication.

[0082] In this embodiment, the isolated power supply is a module designed based on the principle of conversion, which can convert one voltage into another while isolating and filtering electrical signals. The core component of the isolated power supply module is a switching circuit. Its operating principle is based on the synergistic effect of a switch tube and a controller to achieve conversion and isolation between input and output voltages. Through the effective control and regulation of its control chip, it can achieve precise regulation and protection of the output voltage, and provide electrical isolation and safety protection between different voltage domains. During use, the isolated power supply mainly regulates, converts, and isolates the input and output voltages of the system, making its VCC power supply to the first digital isolator, the second digital isolator, the first level conversion module, and the second level conversion module less susceptible to interference factors, thereby protecting the circuit. Since the first digital isolator and the second digital isolator are devices that implement digital signal transmission in an electrical isolator state, the digital isolators effectively isolate the electrical interference between the input and output signals of the first level conversion module and the second level conversion module, respectively, and reduce ground loop noise, thereby more stably and efficiently converting the serial port TTL signal to RS-485 or RS-232 levels through the first level conversion module and the second level conversion module.

[0083] The level conversion isolation circuit of the present invention includes an isolated power supply, two level conversion modules and a digital isolator, which can maintain electrical isolation between modules, avoid interference between modules, and isolate the electrical connection between input signals and output signals. In the electrical isolator state, more stable signal conversion and transmission are achieved. At the same time, the isolated power supply can convert the input voltage into another voltage, so that the utility model can provide electrical isolation and safety protection between different voltage domains. When the first level conversion module, the second level conversion module and the digital isolator need power supply, they are not easily affected by electrical interference signals, thereby ensuring the reliability and stability of the circuit.

[0084] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A level conversion isolation circuit, characterized in that: include: An isolated power supply, a first level conversion module, a second level conversion module, and a digital isolator; Wherein, the isolated power supply is unidirectionally electrically connected to the first level conversion module and the second level conversion module; The first level conversion module and the second level conversion module are connected to the digital isolator; The digital isolator includes a first digital isolator and a second digital isolator; wherein the first digital isolator is used to connect to the first level conversion module; the second digital isolator is used to connect to the second level conversion module; The first digital isolator and the second digital isolator both include: a digital isolation chip; The first power port of the digital isolation chip is connected to the power supply voltage; the second power port of the digital isolation chip is connected to the isolated power supply voltage; The first digital isolator and the second digital isolator both further include: a third capacitor and a fourth capacitor; The first power supply ports of the digital isolation chips of the first digital isolator and the second digital isolator are grounded through a third capacitor; the second power supply ports of the digital isolation chips of the first digital isolator and the second digital isolator are grounded through a fourth capacitor.

2. The isolation circuit for level conversion according to claim 1, characterized in that: The isolated power supply includes an output device; The output device is unidirectionally electrically connected to the first level conversion module and the second level conversion module; The output device is used to output an isolated power supply voltage.

3. The isolation circuit for level conversion according to claim 1, wherein: It also includes a main control chip; the main control chip is used to connect with the digital isolator.

4. The isolation circuit for level conversion according to claim 1, characterized in that: It also includes an external interface; the external interface is used to connect with the first level conversion module and the second level conversion module.

5. The isolation circuit for level conversion according to claim 1, characterized in that: The digital isolation chip is a chip with model number Π122U31.

6. The isolation circuit for level conversion according to claim 1, characterized in that: The first level conversion module includes: a first level conversion chip and a plurality of TVS tubes; The first port to the fourth port of the first level conversion chip are grounded through a TVS tube.

7. The isolation circuit for level conversion according to claim 6, characterized in that: The model of the first level conversion chip is TPT3232E-SO3R.

8. The isolation circuit for level conversion according to claim 1, characterized in that: The second level conversion module includes: a second level conversion chip, an amplifier circuit and an electrostatic diode; An enable port of the second level conversion chip is connected to the amplifier circuit; and an output port of the second level conversion chip is connected to the electrostatic diode.

9. The isolation circuit for level conversion according to claim 8, characterized in that: The model of the second level conversion chip is TP8485E-SR.

10. The isolation circuit for level conversion according to claim 1, characterized in that: The isolated power supply uses a chip with model number B0303S-1WR3.

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