Communication circuit with digital isolation

Abstract

The communication circuit with digital isolation provided in this application is composed of a serial port driver chip and a digital isolation chip. The serial port driver chip converts the USB port on the computer into a virtual COM port, providing an access port in the form of external device access port X2. The device to be connected is connected to the computer through the virtual COM port provided by the interface conversion module. The digital isolation module isolates the power supply and ground on the computer from the device to be communicated, so that the noise of the mains power supply will not affect the data transmission of the access device, ensuring the accuracy of data transmission.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a communication circuit with digital isolation. Background Technology

[0002] Most existing portable devices such as ambulatory blood pressure monitors and electrocardiogram (ECG) loggers require periodic data transmission to external devices such as PCs, laptops, or cloud servers for analysis. Data transmission methods generally include wireless and wired communication, but both have drawbacks. Wireless communication suffers from limited transmission distance, low transmission speed, and rapid battery drain. Wired communication is less resistant to interference. Although most portable devices like ambulatory blood pressure monitors and ECG loggers operate on batteries, when communicating with a computer or laptop, the computer or laptop is usually connected to mains power. Since serial communication (such as RS232) uses voltage level changes to transmit data, it is sensitive to electromagnetic interference; in environments with high mains power noise, serial communication may experience data errors or communication failures. Summary of the Invention

[0003] To address the problem in existing technologies where wired communication between battery-powered devices and computers is susceptible to data errors or communication failures due to noise interference from the mains power supply, this invention provides a communication circuit with digital isolation. This circuit isolates the power supply and ground of the computer from the communication device, preventing mains power noise from affecting battery-powered devices and ensuring data accuracy.

[0004] The structure of the present invention is as follows: a communication circuit with digital isolation, characterized in that it includes: a computer interface, an external device access port, and a main circuit, wherein the main circuit includes: an interface conversion module and a digital isolation module; The computer interface is connected to the USB port on the computer. The interface conversion module virtualizes the USB port on the computer into a COM port, providing an access port for the external serial device to be connected, thus forming the external device access port. The digital isolation module is electrically connected to the interface conversion module, isolating the power and ground in the USB port on the computer from the access device, and providing a stable power supply for data transmission from the external device access port. The interface conversion module is implemented based on the CP2102 serial port driver chip. The digital isolation module is implemented based on the digital isolation chip ADuM3201.

[0005] Its further features are: The main circuit includes: serial port driver chip U1, digital isolation chip U4, computer interface X1, external device access port X2, diodes D1~D3, capacitors C1~C3, and resistor R1. Pin 3 of the serial port driver chip U1 is grounded. Pin 4 of the serial port driver chip U1 is connected to the negative terminal of diode D1 and pin 3 of the computer interface X1. Pin 5 of the serial port driver chip U1 is connected to the negative terminal of diode D2 and pin 2 of the computer interface X1. Pin 6 of the serial port driver chip U1 is connected to one end of capacitor C3 and then connected to the power supply. The other end of capacitor C3 is grounded. Pin 7 of the serial port driver chip U1 is connected to pin 8, one end of capacitor C1, one end of capacitor C2, the negative terminal of diode D3, and pin 1 of the computer interface X1. The positive terminals of diodes D1, D2, and D3, the other end of capacitor C1, and the other end of capacitor C2 are grounded. Pin 9 of the serial port driver chip U1 is connected to one end of resistor R1, and the other end of resistor R2 is connected to the power supply. Pin 26 of the serial port driver chip U1 is connected to pin 3 of the digital isolation chip U4. Pin 25 of the serial port driver chip U1 is connected to pin 2 of the digital isolation chip U4. Pin 1 of the digital isolation chip U4 is connected to the power supply VCC. Pin 4 of the digital isolation chip U4 is grounded. Pin 8 of the digital isolation chip U4 is connected to AVDD. Pin 7 of the digital isolation chip U4 is connected to pin 1 of the external device access port X1. Pin 6 of the digital isolation chip U4 is connected to pin 2 of the external device access port X2. Pin 5 of the digital isolation chip U4 is connected to pin 3 of the external device access port X2 and then connected to AVSS. It also includes: a voltage regulator module and a power supply module; The voltage regulator module supplies power to the digital isolation chip via the power supply of the computer's USB port. The power module supplies power to the digital isolation chip based on a battery. The voltage regulator module includes: a voltage regulator chip U5, capacitors C8 and C9, and an electrolytic capacitor CT4; Pins 1 and 3 of the voltage regulator chip U5 are connected to pin 1 of the computer interface X1. Pin 2 of the voltage regulator chip U5 is grounded. Pin 4 of the voltage regulator chip U5 is connected to one end of the capacitor C8. The other end of the capacitor C8 is grounded. Pin 5 of the voltage regulator chip U5 is connected to the positive terminal of the electrolytic capacitor CT4, one end of the capacitor C9, and then connected to VCC. The negative terminal of the electrolytic capacitor and the other end of the capacitor C9 are grounded. The power module includes: a voltage regulator chip U6, a battery connection port XS1, capacitors C4, C6 and C7, and electrolytic capacitors CT1 and CT3; Pin 1 of the voltage regulator chip U6 is connected to pin 2 of the battery connection port X1, the positive terminal of the electrolytic capacitor CT1, one end of the capacitor C4, and pin 3 of the voltage regulator chip U6. Pin 2 of the voltage regulator chip U6 is connected to AVSS. Pin 5 of the voltage regulator chip U6 is connected to the positive terminal of the electrolytic capacitor CT3, one end of the capacitor C7, and then connected to AVDD. Pin 4 of the voltage regulator chip U6 is connected to one end of the capacitor C6, and the other end of the capacitor C6 is grounded.

[0006] The communication circuit with digital isolation provided in this application is composed of a serial port driver chip and a digital isolation chip. The serial port driver chip converts the USB port on the computer into a virtual COM port, providing an access port in the form of external device access port X2. The device to be connected is connected to the computer through the virtual COM port provided by the interface conversion module. The digital isolation module isolates the power supply and ground on the computer from the device to be communicated, so that the noise of the mains power supply will not affect the data transmission of the access device, ensuring the accuracy of data transmission. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of the main circuit of the communication circuit with digital isolation according to this application; Figure 2 This is the circuit diagram of the voltage regulator module; Figure 3 This is the circuit diagram of the power supply module. Detailed Implementation

[0008] This application includes a communication circuit with digital isolation, characterized in that it includes: a computer interface, an external device access port, and a main circuit, the main circuit including: an interface conversion module, a digital isolation module, a voltage regulator module, and a power supply module.

[0009] The computer interface connects to the computer's USB port. The interface conversion module virtualizes the computer's USB port into a COM port, providing an access port for the external serial device to be connected, thus forming an external device access port. The digital isolation module is electrically connected to the interface conversion module, isolating the power and ground of the computer's USB port from the access device, and providing a stable power supply for data transmission from the external device access port, so that the data transmission of the external access device is not affected by the power supply noise from the computer.

[0010] The voltage regulator module supplies power to the digital isolation chip via the computer's USB port; the power supply module provides a stable power supply to the digital isolation chip via a battery.

[0011] In this application, the interface conversion module is implemented based on the serial port driver chip CP2102; the digital isolation module is implemented based on the digital isolation chip ADuM3201; and the voltage regulation module and power supply module are both implemented based on the low dropout voltage regulator chip TPS73633 to achieve power regulation.

[0012] The CP2102 is an oscillator with high integration, capable of housing a USB 2.0 full-speed controller, USB transceiver, crystal oscillator, EEPROM, and asynchronous serial data bus (UART). It supports full-function modem signals without requiring any external USB devices. The CP2102 uses a driver to virtualize the PC's USB port as a COM port for expansion purposes.

[0013] The ADuM3201 chip employs Analog Devices' iCoupler technology in a dual-channel digital isolator, integrating high-speed CMOS with single-chip transformer technology. This eliminates problems commonly associated with optocouplers, such as uncertain current transfer ratios, nonlinear transfer functions, and the effects of temperature and lifespan. The ADuM3201 isolator provides two independent isolation channels, supporting various channel configurations and data rates. In the application scenarios described in this application, it can securely isolate data transmission between the computer and external access devices.

[0014] like Figure 1 As shown, the main circuit includes: serial port driver chip U1, digital isolation chip U4, computer interface X1, external device access port X2, diodes D1~D3, capacitors C1~C3, and resistor R1. Pin 3 of serial port driver chip U1 is grounded. Pin 4 of serial port driver chip U1 is connected to the cathode of diode D1 and pin 3 of computer interface X1. Pin 5 of serial port driver chip U1 is connected to the cathode of diode D2 and pin 2 of computer interface X1. Pin 6 of serial port driver chip U1 is connected to one end of capacitor C3 and then to the power supply. The other end of capacitor C3 is grounded. Pin 7 of serial port driver chip U1 is connected to pin 8, one end of capacitor C1, one end of capacitor C2, the cathode of diode D3, and pin 1 of computer interface X1. The anodes of diodes D1, D2, and D3, the other end of capacitor C1, and the other end of capacitor C2 are grounded. Pin 9 of serial port driver chip U1 is connected to... Connect one end of resistor R1, and connect the other end of resistor R2 to the power supply. Connect pin 26 of serial port driver chip U1 to pin 3 of digital isolation chip U4. Connect pin 25 of serial port driver chip U1 to pin 2 of digital isolation chip U4. Connect pin 1 of digital isolation chip U4 to power supply VCC. Connect pin 4 of digital isolation chip U4 to ground. Connect pin 8 of digital isolation chip U4 to AVDD. Connect pin 7 of digital isolation chip U4 to pin 1 of external device access port X1. Connect pin 6 of digital isolation chip U4 to pin 2 of external device access port X2. Connect pin 5 of digital isolation chip U4 to pin 3 of external device access port X2 and then to AVSS.

[0015] In practical use, the computer interface X1 connects to the computer's USB port and the CP2102. A virtual serial port is generated on the computer, and the high reverse blocking capability of D1, D2, and D3 protects the CP2102 from damage caused by instantaneous voltage changes on the computer. Portable devices such as dynamic blood pressure monitors and ECG acquisition devices are connected to the external device access port X2 for data transmission.

[0016] like Figure 2 As shown, the voltage regulator module includes: voltage regulator chip U5, capacitors C8 and C9 and electrolytic capacitor CT4; voltage regulator chip U5 is based on voltage regulator chip TPS73633.

[0017] Pins 1 and 3 of voltage regulator chip U5 are connected to pin 1 of computer interface X1. Pin 2 of voltage regulator chip U5 is grounded. Pin 4 of voltage regulator chip U5 is connected to one end of capacitor C8, and the other end of capacitor C8 is grounded. Pin 5 of voltage regulator chip U5 is connected to the positive terminal of electrolytic capacitor CT4, one end of capacitor C9, and then connected to VCC. The negative terminal of electrolytic capacitor and the other end of capacitor C9 are grounded.

[0018] like Figure 3 As shown, the power module includes: a voltage regulator chip U6, a battery connection port XS1, capacitors C4, C6 and C7, and electrolytic capacitors CT1 and CT3; the voltage regulator chip U6 is implemented using the voltage regulator chip TPS73633.

[0019] Pin 1 of voltage regulator chip U6 is connected to pin 2 of battery connection port X1, the positive terminal of electrolytic capacitor CT1, one end of capacitor C4, and pin 3 of voltage regulator chip U6. Pin 2 of voltage regulator chip U6 is connected to AVSS. Pin 5 of voltage regulator chip U6 is connected to the positive terminal of electrolytic capacitor CT3, one end of capacitor C7, and then connected to AVDD. Pin 4 of voltage regulator chip U6 is connected to one end of capacitor C6, and the other end of capacitor C6 is grounded.

[0020] Connecting the U6 lithium battery to the voltage regulator chip via the XS1 battery connection port allows you to use either the battery from the connected device or a separate lithium battery. Choose the appropriate option based on your needs.

[0021] The two isolation channels of the digital isolation chip U4 correspond to different power supply voltages; one of the voltages comes from the voltage regulator module, which is obtained by regulating the 5V voltage from pin 1 of the computer's USB port through the voltage regulator chip U5 to obtain VCC (3.3V), and the ground wire is connected to the computer's ground wire.

[0022] The voltage at the other end of the digital isolation chip U4 comes from the power module. The voltage of the lithium battery connected from the battery connection port XS1 is regulated by U6 to obtain AVDD (3.3V). The ground wire at this end is connected to the negative terminal of the lithium battery. The data transmission of external devices connected from the external device access port X2 is powered by the DC power supply of the power module and will not be affected by the noise of the power supply from the computer interface X1, which can effectively improve the stability and reliability of data transmission.

Claims

1. A communication circuit with digital isolation, characterized in that, It includes: The system includes a computer interface, an external device access port, and a main circuit, wherein the main circuit includes an interface conversion module and a digital isolation module. The computer interface is connected to the USB port on the computer. The interface conversion module virtualizes the USB port on the computer as a COM port, providing an access port for the external serial device to be connected, thus forming the external device access port. The digital isolation module is electrically connected to the interface conversion module, isolating the power and ground in the USB port on the computer from the access device, and providing a stable power supply for data transmission from the external device access port.

2. The communication circuit with digital isolation according to claim 1, characterized in that: The interface conversion module is implemented based on the serial port driver chip CP2102; the digital isolation module is implemented based on the digital isolation chip ADuM3201.

3. The communication circuit with digital isolation according to claim 2, characterized in that: The main circuit includes: serial port driver chip U1, digital isolation chip U4, computer interface X1, external device access port X2, diodes D1~D3, capacitors C1~C3, and resistor R1. Pin 3 of the serial port driver chip U1 is grounded. Pin 4 of the serial port driver chip U1 is connected to the negative terminal of diode D1 and pin 3 of the computer interface X1. Pin 5 of the serial port driver chip U1 is connected to the negative terminal of diode D2 and pin 2 of the computer interface X1. Pin 6 of the serial port driver chip U1 is connected to one end of capacitor C3 and then connected to the power supply. The other end of capacitor C3 is grounded. Pin 7 of the serial port driver chip U1 is connected to pin 8, one end of capacitor C1, one end of capacitor C2, the negative terminal of diode D3, and pin 1 of the computer interface X1. The positive terminals of diodes D1, D2, and D3, the other end of capacitor C1, and the other end of capacitor C2 are grounded. Pin 9 of the serial port driver chip U1 is connected to one end of resistor R1, and the other end of resistor R2 is connected to the power supply. Pin 26 of the serial port driver chip U1 is connected to pin 3 of the digital isolation chip U4. Pin 25 of the serial port driver chip U1 is connected to pin 2 of the digital isolation chip U4. Pin 1 of the digital isolation chip U4 is connected to the power supply VCC. Pin 4 of the digital isolation chip U4 is grounded. Pin 8 of the digital isolation chip U4 is connected to AVDD. Pin 7 of the digital isolation chip U4 is connected to pin 1 of the external device access port X1. Pin 6 of the digital isolation chip U4 is connected to pin 2 of the external device access port X2. Pin 5 of the digital isolation chip U4 is connected to pin 3 of the external device access port X2 and then connected to AVSS.

4. The communication circuit with digital isolation according to claim 3, characterized in that: It also includes: a voltage regulator module and a power supply module; The voltage regulator module supplies power to the digital isolation chip via the power supply of the computer's USB port. The power module supplies power to the digital isolation chip based on a battery.

5. The communication circuit with digital isolation according to claim 4, characterized in that: The voltage regulator module includes: a voltage regulator chip U5, capacitors C8 and C9, and an electrolytic capacitor CT4; Pins 1 and 3 of the voltage regulator chip U5 are connected to pin 1 of the computer interface X1. Pin 2 of the voltage regulator chip U5 is grounded. Pin 4 of the voltage regulator chip U5 is connected to one end of the capacitor C8. The other end of the capacitor C8 is grounded. Pin 5 of the voltage regulator chip U5 is connected to the positive terminal of the electrolytic capacitor CT4, one end of the capacitor C9, and then connected to VCC. The negative terminal of the electrolytic capacitor and the other end of the capacitor C9 are grounded.

6. The communication circuit with digital isolation according to claim 5, characterized in that: The power module includes: a voltage regulator chip U6, a battery connection port XS1, capacitors C4, C6 and C7, and electrolytic capacitors CT1 and CT3; Pin 1 of the voltage regulator chip U6 is connected to pin 2 of the battery connection port X1, the positive terminal of the electrolytic capacitor CT1, one end of the capacitor C4, and pin 3 of the voltage regulator chip U6. Pin 2 of the voltage regulator chip U6 is connected to AVSS. Pin 5 of the voltage regulator chip U6 is connected to the positive terminal of the electrolytic capacitor CT3, one end of the capacitor C7, and then connected to AVDD. Pin 4 of the voltage regulator chip U6 is connected to one end of the capacitor C6, and the other end of the capacitor C6 is grounded.

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