Capacitive coupling communication circuit
Through the capacitor coupling communication circuit and the voltage stabilizing clamp circuit, the problem of high isolation communication cost between electric equipment and lithium batteries is solved, low-cost and reliable short-distance communication is achieved, and damage to the isolation chip is avoided.
Patent Information
- Application Number
- CN202422771206.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-14
- Publication Date
- 2025-09-12
- Estimated Expiration
- 2034-11-14
AI Technical Summary
Existing isolated communication between electric devices and lithium batteries is expensive and susceptible to interference from communication lines, which can damage the isolation chip, making it difficult to use in cost-sensitive applications.
A capacitive coupling communication circuit is used to achieve communication between devices through capacitive coupling. A voltage stabilizing clamp circuit and a clamp protection circuit are used to avoid dedicated isolation chips. Combined with overcurrent protection resistors, it ensures that the signal complies with the TTL standard and filters out low-frequency interference.
It reduces communication costs, improves communication reliability and security, avoids damage to the isolation chip, and is suitable for communication between short-distance common-ground devices.
Smart Images
Figure CN223334673U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of communication between short-distance common-ground devices, and in particular relates to a capacitive coupling communication circuit. Background Art
[0002] To make electric devices scalable and upgradeable, they often need to communicate with the outside world (such as lithium batteries). Wireless communication is costly and unsuitable for applications with relatively simple functions and strict cost requirements. Traditionally, communication methods such as RS232, RS485, and IIC typically require the use of specialized isolation chips to ensure compatibility at the power level, but this still increases costs. Furthermore, traditional circuits are still vulnerable to damage to the isolation chip caused by interference and misconnections of communication lines. The only way to control the damage is to the interface to avoid damage to core components. Summary of the Invention
[0003] Purpose of the invention: In order to solve the problem of high isolation cost between electric equipment and lithium batteries in the prior art, the utility model provides a capacitive coupling communication circuit.
[0004] Technical solution: A capacitor-coupled communication circuit, including a first port, a second port, a third port, a fourth port, a first overcurrent protection resistor R4, a second overcurrent protection resistor R5, a capacitor C1, a voltage regulator clamp circuit and a clamp protection circuit, wherein the first port is used to connect to the receiving pin of the battery MCU, the second port is used to connect to the sending pin of the battery MCU, the third port is used to connect to the electric device, and the fourth port is used to connect to the common end; the first port and the second port are connected to the first end of the capacitor C1 through the first overcurrent protection resistor R4 and the second protection resistor R5 respectively, and the other end of the capacitor C1 is connected to the electric device through the resistor R1; the voltage regulator clamp circuit and the clamp protection circuit are connected to the first end of the capacitor C1.
[0005] Furthermore, the voltage stabilizing clamp circuit includes a diode D1, a diode D2, a voltage stabilizing diode ZR1, a resistor R2, and a resistor R3. The positive electrode of the diode D1 is connected to the power pin of the battery MCU, and the negative electrode is connected to the resistor R2. The other end of the resistor R2 is connected to one end of the resistor R3, the negative electrode of the voltage stabilizing diode ZR1, and the negative electrode of the diode D2. The positive electrode of the voltage stabilizing diode ZR1 is grounded, and the other end of the resistor R3 and the positive electrode of the diode D2 are connected to the first end of the capacitor C1.
[0006] Furthermore, the clamping protection circuit includes a diode D3 and a diode D4, wherein the anode of the diode D3 is connected to the first end of the capacitor C1 and the cathode is connected to the power supply, and the anode of the diode D4 is grounded and the cathode is connected to the first end of the capacitor C1.
[0007] Furthermore, a resistor R6 is included, one end of the resistor R6 is connected to the first end of the capacitor C1, and the other end is connected to the ground.
[0008] Furthermore, the power supply is 5V.
[0009] Furthermore, the stabilizing voltage of the zener diode ZR1 is 2.7V.
[0010] Compared with the existing technology, the capacitive coupling communication circuit provided by the present invention is suitable for communication between short-distance common-ground devices. It does not use a dedicated isolation chip, which can further reduce costs. The coupling between communication signals is achieved through an independent capacitor, and the specifications can be selected according to the actual application scenario, which is more flexible and safer. After the signal passes through the circuit, the high-frequency part will pass through completely, but since the number of Bit1 and Bit0 in a frame transmission is not exactly equal, a low-frequency signal equivalent to the frame period will pass through the capacitor to a certain extent. The amplitude of the low-frequency signal depends on the frame content. The circuit after the capacitor can filter out this low-frequency signal and restore it to a combination of Bit0 and Bit1 that the processor can recognize, ensuring reliable communication. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 This is the circuit schematic diagram of the capacitive coupling communication circuit. DETAILED DESCRIPTION
[0012] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.
[0013] like Figure 1 As shown, a capacitive coupling communication circuit includes a first port Rx, a second port Tx, a third port B+, a fourth port COM-, a first overcurrent protection resistor R4, a second overcurrent protection resistor R5, a capacitor C1, a voltage stabilizing clamp circuit and a clamp protection circuit, wherein the first port is used to connect to the receiving pin of the battery MCU, the second port is used to connect to the transmitting pin of the battery MCU, the third port is used to connect to the electric device, and the fourth port is used to connect to the common end; the first port and the second port are respectively connected to the first end of the capacitor C1 through the first overcurrent protection resistor R4 and the second protection resistor R5, and the other end of the capacitor C1 is connected to the electric device through the resistor R1; the voltage stabilizing clamp circuit and the clamp protection circuit are connected to the first end of the capacitor C1.
[0014] The voltage stabilizing clamp circuit includes a diode D1, a diode D2, a voltage stabilizing diode ZR1, a resistor R2, and a resistor R3. The positive electrode of the diode D1 is connected to the power pin of the battery MCU, and the negative electrode is connected to the resistor R2. The other end of the resistor R2 is connected to one end of the resistor R3, the negative electrode of the voltage stabilizing diode ZR1, and the negative electrode of the diode D2. The positive electrode of the voltage stabilizing diode ZR1 is grounded, and the other end of the resistor R3 and the positive electrode of the diode D2 are connected to the first end of the capacitor C1.
[0015] The clamping protection circuit includes a diode D3 and a diode D4. The anode of the diode D3 is connected to the first end of the capacitor C1, and the cathode is connected to a 5V power supply. The anode of the diode D4 is grounded, and the cathode is connected to the first end of the capacitor C1.
[0016] A resistor R6 is further included, one end of the resistor R6 is connected to the first end of the capacitor C1 , and the other end of the resistor R6 is connected to the ground.
[0017] The stabilizing voltage of the zener diode ZR1 is 2.7V.
[0018] This circuit connects a lithium-ion battery to an electric device, using half-duplex UART communication between the device and the battery. When the electric device sends a signal to the battery-powered MCU, the signal is coupled through capacitor C1 and passed through the first overcurrent protection resistor R4 before being recognized by the MCU. A 2.7V Zener diode ZR1 and diode D2 clamp the signal to 3.3V, ensuring that the high and low voltage levels conform to TTL standards and removing low-frequency signals caused by frame content. The signal from the MCU passes through the second overcurrent protection resistor R5 and is coupled by capacitor C1 onto the communication line to the electric device. Diodes D3 and D4 form a clamping protection circuit, with R4 and R5 acting as overcurrent protection resistors. These two protection methods protect the MCU pins from damage caused by abnormal interference. Diode D1, resistors R2 and R3, Zener diode ZR1, and diode D2 form a 2.7V voltage-stabilizing clamping circuit. This circuit is powered by the MCU pin, ENcomV, allowing it to be shut down during sleep mode, reducing power consumption. After the voltage regulator clamp circuit clamps the high level of the received signal to 3.3V, the communication bit1 and bit0 are in line with the TTL standard.
[0019] After the signal passes through the circuit, the high-frequency portion will pass through completely. However, since the number of Bit1 and Bit0 in a frame transmission is not exactly equal, a low-frequency signal equivalent to the frame period will pass through the capacitor to a certain extent. The amplitude of this low-frequency signal depends on the frame content. Therefore, the circuit after passing through the capacitor needs to remove this low-frequency signal and restore it to the Bit0 and Bit1 combination that the processor can recognize to ensure reliable communication.
Claims
1. A capacitive coupling communication circuit, characterized in that: It includes a first port, a second port, a third port, a fourth port, a first overcurrent protection resistor R4, a second overcurrent protection resistor R5, a capacitor C1, a voltage stabilizing clamp circuit and a clamp protection circuit. The first port is used to connect to the receiving pin of the battery MCU, the second port is used to connect to the sending pin of the battery MCU, the third port is used to connect to the electric device, and the fourth port is used to connect to the common end; the first port and the second port are connected to the first end of the capacitor C1 through the first overcurrent protection resistor R4 and the second protection resistor R5 respectively, and the other end of the capacitor C1 is connected to the electric device through the resistor R1; the voltage stabilizing clamp circuit and the clamp protection circuit are connected to the first end of the capacitor C1.
2. The capacitive coupling communication circuit according to claim 1, wherein: The voltage stabilizing clamp circuit includes a diode D1, a diode D2, a voltage stabilizing diode ZR1, a resistor R2, and a resistor R3. The positive electrode of the diode D1 is connected to the power pin of the battery MCU, and the negative electrode is connected to the resistor R2. The other end of the resistor R2 is connected to one end of the resistor R3, the negative electrode of the voltage stabilizing diode ZR1, and the negative electrode of the diode D2. The positive electrode of the voltage stabilizing diode ZR1 is grounded, and the other end of the resistor R3 and the positive electrode of the diode D2 are connected to the first end of the capacitor C1.
3. The capacitive coupling communication circuit according to claim 1 or 2, characterized in that: The clamping protection circuit includes a diode D3 and a diode D4. The anode of the diode D3 is connected to the first end of the capacitor C1, and the cathode is connected to the power supply. The anode of the diode D4 is grounded, and the cathode is connected to the first end of the capacitor C1.
4. The capacitive coupling communication circuit according to claim 1 or 2, characterized in that: A resistor R6 is further included, one end of the resistor R6 is connected to the first end of the capacitor C1 , and the other end of the resistor R6 is connected to the ground.
5. The capacitive coupling communication circuit according to claim 3, wherein: The power supply is 5V.
6. The capacitive coupling communication circuit according to claim 2, wherein: The stabilizing voltage of the zener diode ZR1 is 2.7V.