This article focuses on the differences between PCB single-point and multi-point grounding.
In circuit board grounding, the goal is to prevent electric shock and ensure equipment safety. The metal chassis or shell of power and telecommunications equipment is connected to the ground wire, with the earth serving as the current loop ground wire. Proper grounding involves a solid electrical connection between the equipment’s neutral point, its shell or support, and the grounding conductor. Grounding helps to divert unwanted current or noise interference away, ultimately protecting users from electric shock. For UPS systems, marking the voltage between the neutral wire and the ground wire ensures that the product does not pose an electric shock risk to users.
1. PCB Single-Point Grounding
For low operating frequencies (<1MHz), single-point grounding is used. In this method, a single structural point in the circuit system serves as the ground reference point, with all ground connections routed to this point and a safety ground bolt in place. This approach helps prevent issues related to two-point grounding, which can cause circuit coupling due to common ground impedance. When employing single-point grounding for multiple circuits, it is preferable to use parallel configurations over series ones to avoid the problems associated with common ground impedance.
1. To prevent power frequency and other stray currents from interfering with the signal ground wire, it should be insulated from the power ground wire and the chassis ground wire. It should only connect to the power ground wire, chassis ground wire, and the safety ground bolt connected to the earth (excluding floating types).
2. PCB Multi-point Grounding
For high working frequencies (>30MHz), the multi-point grounding method is used (i.e., a grounding plate replaces individual ground loops in different parts of the circuit). Since the inductance of the ground lead is proportional to frequency and length, higher operating frequencies increase the common ground impedance, which heightens electromagnetic interference. Thus, the ground wire length should be minimized. When implementing multi-point grounding, always connect to the nearest low-resistance ground plane.
3. PCB Mixed Grounding
For circuits operating between 1 and 30MHz, mixed grounding is used. If the ground wire length is less than 1/20 of the wavelength of the working signal, single-point grounding is applied; otherwise, multi-point grounding is used.
The above provides an overview of the differences between PCB single-point and multi-point grounding. It is hoped that beginner PCB designers will gain a clear understanding of these grounding techniques.
In circuit board grounding, the goal is to prevent electric shock and ensure equipment safety. The metal chassis or shell of power and telecommunications equipment is connected to the ground wire, with the earth serving as the current loop ground wire. Proper grounding involves a solid electrical connection between the equipment’s neutral point, its shell or support, and the grounding conductor. Grounding helps to divert unwanted current or noise interference away, ultimately protecting users from electric shock. For UPS systems, marking the voltage between the neutral wire and the ground wire ensures that the product does not pose an electric shock risk to users.
1. PCB Single-Point Grounding
For low operating frequencies (<1MHz), single-point grounding is used. In this method, a single structural point in the circuit system serves as the ground reference point, with all ground connections routed to this point and a safety ground bolt in place. This approach helps prevent issues related to two-point grounding, which can cause circuit coupling due to common ground impedance. When employing single-point grounding for multiple circuits, it is preferable to use parallel configurations over series ones to avoid the problems associated with common ground impedance.
1. To prevent power frequency and other stray currents from interfering with the signal ground wire, it should be insulated from the power ground wire and the chassis ground wire. It should only connect to the power ground wire, chassis ground wire, and the safety ground bolt connected to the earth (excluding floating types).
2. PCB Multi-point Grounding
For high working frequencies (>30MHz), the multi-point grounding method is used (i.e., a grounding plate replaces individual ground loops in different parts of the circuit). Since the inductance of the ground lead is proportional to frequency and length, higher operating frequencies increase the common ground impedance, which heightens electromagnetic interference. Thus, the ground wire length should be minimized. When implementing multi-point grounding, always connect to the nearest low-resistance ground plane.
3. PCB Mixed Grounding
For circuits operating between 1 and 30MHz, mixed grounding is used. If the ground wire length is less than 1/20 of the wavelength of the working signal, single-point grounding is applied; otherwise, multi-point grounding is used.
The above provides an overview of the differences between PCB single-point and multi-point grounding. It is hoped that beginner PCB designers will gain a clear understanding of these grounding techniques.
