The mystery of “ground” in circuit design: detailed explanation of classification and function application

Infineon / Mitsubishi / Fuji / Semikron / Eupec / IXYS

The mystery of “ground” in circuit design: detailed explanation of classification and function application

Posted Date: 2024-01-12

In circuit design, ground is a crucial concept. It assumes multiple responsibilities such as guiding current, stabilizing voltage, and protecting equipment in the circuit. To better understand the role of ground in a circuit and its detailed classification, we need to delve deeper into this mysterious yet critical element.

1. Basic concept of land

Ground is a common reference point in a circuit and is usually defined as the zero potential point of the circuit. It is the reference to the zero point of the potential in the entire circuit and provides a baseline for the measurement of other voltages. Theoretically, the ground is non-conductive, but in actual circuits, the ground usually refers to a conductive path in the circuit, ensuring the return flow of current to maintain the normal operation of the circuit.

2. Classification of land

In circuit design, grounds can be classified based on their function and how they are connected. Main land types include:

Signal Ground: The ground used for transmitting signals is the reference for signals in the circuit. In analog and digital circuits, signal ground is often a common reference point to ensure accurate transmission of signals.

Power Ground: Ground connected to the power supply and used to provide a reference for the power supply voltage. The stability of the power ground is critical to the normal operation of the circuit, as it ensures the accuracy and stability of the power supply voltage.

Ground Plane: It is an extended conductive area, usually located on one layer of the circuit board, used to provide a low-impedance ground connection. A ground plane helps reduce electromagnetic interference (EMI) and improve signal integrity.

Protective Ground: Ground used to protect equipment and personnel. This is connected to the equipment enclosure and is used to eliminate possible electrical shock hazards.

Virtual Ground: In some circuits, virtual ground is a ground simulated through circuit design to simplify circuit analysis and improve performance.

3. The function and application of earth

Current return path: Ground provides a path for current to return, ensuring that the current is closed in the circuit. This is essential to keep the circuit working properly, as the current needs to make a complete circuit.

Stable voltage: The power ground helps stabilize the power supply voltage, ensuring that other parts of the circuit are operating at the correct potential level. A stable power ground is critical to the performance and longevity of electronic equipment.

Reduce electromagnetic interference: The use of a ground plane helps reduce electromagnetic interference and improve the anti-interference ability of the circuit. This is important to ensure signal integrity and reduce the radiation levels of the circuit.

Prevent the risk of electric shock: The protective ground is connected to the device shell to prevent the device shell from becoming electrified and reduce the risk of electric shock. This is particularly important in household appliances and industrial equipment.

Signal Reference: Signal ground is used in analog and digital circuits to reference signals. It ensures that all parts use the same signal reference, thus maintaining signal accuracy.

Improve performance: The use of virtual ground can simplify circuit design and improve performance. By simulating a virtual ground, an equivalent reference point can be introduced into the circuit to simplify the analysis process.

4. Ground design considerations

Separate different land types: Different land types should be designed separately to avoid affecting each other. Especially in high-frequency circuits, ground separation is more important.

Ground conductivity: The ground conductivity needs to be good enough to ensure that current can flow back smoothly. A low-impedance ground connection helps reduce voltage drop and improve circuit stability.

Ground wiring: In circuit board design, reasonable ground wiring is the key to ensuring circuit performance. Ground plane placement and connections require careful consideration.

Connection of protective ground: The protective ground needs to be securely connected to the equipment shell to provide effective safety protection.

Anti-interference design of signal ground: When designing signal ground, methods to reduce electromagnetic interference need to be considered, such as reasonable wiring and shielding measures.

Therefore, ground is a crucial and complex concept in circuit design. Different types of grounds play different roles in electrical circuits, from providing a reference point to protecting equipment and personnel. Proper design and use of ground is a critical step in ensuring that circuits work properly, improve performance, and ensure safety. By deeply understanding the classification, role, and application of earth, we can better address the challenges in complex circuit design, thereby creating more stable and efficient electronic devices.

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