The grounding method of PCB board

      The GND (Ground) on the circuit diagram and PCB board represents the ground wire or 0 wire, and GND means the common end, which can also be said to be the ground. The so-called PCB board grounding refers to connecting all ground wires to the power supply ground wire.

1、 Single point and multi-point grounding methods for PCB boards

① Single point grounding: The grounding wires of all circuits are connected to the same point on the ground plane, which can be divided into series single point grounding and parallel single point grounding.
② Multi point grounding: The ground wire of all circuits is grounded nearby, and the ground wire is very short, suitable for high-frequency grounding.
③ Hybrid grounding: Mix single point grounding and multi-point grounding.
      Between low-frequency, low-power, and the same power layer, single point grounding is the most suitable and is usually applied in analog circuits; The star type connection is generally used here to reduce the potential impact of series impedance. High frequency digital circuits require parallel grounding, which can be easily handled through a grounding hole; Generally, all modules will use a combination of two grounding methods, using a hybrid grounding method to connect the circuit ground wire to the ground plane.

2、 PCB board mixed grounding method

      If you do not choose to use the entire plane as a common ground wire, such as when the module itself has two ground wires, you need to segment the ground plane, which often interacts with the power plane. The connection method between the ground is as follows:
① Common wiring connection between ground circuit boards: This method can ensure reliable low impedance conduction between the two ground wires, but is only limited to the connection between the ground of medium and low frequency signal circuits.
② Ground to ground high resistance connection: The characteristic of high resistance is that once there is a voltage difference between the two ends of the resistance, a weak conduction current will be generated, which releases the charge on the ground wire and ultimately achieves zero voltage difference between the two ends.
③ Ground to ground capacitance connection: The characteristics of capacitors are DC cutoff and AC conduction, which are applied in floating ground systems.
④ Ground to ground magnetic bead connection: Magnetic beads are equivalent to a resistance that varies with frequency and exhibit resistance characteristics. Applied between ground for weak signals with rapid small current fluctuations.
⑤ Ground to ground inductive connection: Inductors have the characteristic of suppressing circuit state changes and can be used for peak shaving and valley filling. They are usually applied between two ground to ground systems with significant current fluctuations.
⑥ Ground to ground small resistance connection: The small resistance adds a damping that hinders the rapid change of ground current overshoot; When the current changes, the rising edge of the impulse current becomes slower.