The production of printed circuit boards is a dynamic process. The world is working towards bettering the operation of printed circuit boards. However, every printed circuit board depends on power from a power supply source. For instance, many different electronic devices, such as computers, servers, and other electronic equipment, require PCB power supplies. A power supply, a power cord, and a power connector normally make up a PCB power supply unit. While the power cord and connection deliver AC power to the power supply, the power supply itself supplies DC power to the PCB. The following details explains the power supply of a printed circuit board.
What is a PCB Power Supply Unit?
A printed circuit board’s power supply is the circuit part where you connect a power source. In addition, the power supply controls the amount of current or voltage getting into the PCB. The power can be either direct (DC) or alternating (AC). However, the two types of power do not have the same features and applications. For instance, AC printed circuit boards are applicable in low-power devices such as home appliances and office electronics. On the other hand, DC electronics are primarily helpful in such high-power fields as military electronics, automotive, and industrial applications.
Classifications of PCB power supplies
We can classify PCB power supplies into two types, namely:
- Linear power supplies
- Switched-mode power supplies
Linear power supplies
Linear power supplies convert AC into DC using a transformer. Moreover, linear power supplies are more efficient and straightforward. However, they are large and bulky. They are, therefore, suitable for applications that are not size and weight sensitive. Industrial systems are a perfect example of such applications.
Switched-mode Power Supplies
On the other hand, switched-mode power supplies convert AC to DC using transistors. Furthermore, unlike linear power supplies, switched-mode power supplies are lighter and smaller. They are therefore suitable for applications such as cell phones and computers, where size and weight matter incredibly.
Spikes and Surges in the Power Supply
The power supply works with specific current and voltage circuit requirements. However, there might be surges and spikes in the current or voltage. We can define a spike as a sudden sharp voltage rise. A surge, on the other hand, is a long-term voltage rise. These two occurrences may damage the power supply and destroy the circuit components. However, a spike and surge protector aids in protecting the power supply and the entire circuit. Spikes and surges result from such causes as faulty equipment, power outages, and lightning strikes.
Power Supply Circuit Protection
The power supply has a voltage regulator that protects the circuit from surges and spikes. The voltage regulator controls the amount of current and voltage from the power supply to the printed circuit board. In other words, the voltage regulator ensures that the power supply produces a safe voltage and current level. Did you know that noise affects the functioning of the power circuit and the entire circuit? To protect the circuit from such damage, the power supply has a filter that eliminates any unnecessary AC noise from the DC power source.
Overcurrent and Overvoltage Protection
The power supply must feature a fuse to safeguard against overvoltage and overcurrent. The fuse is a device that shuts off the circuit when the voltage or current from the power supply is too high. In addition, short circuits can damage. Short circuits occur when the current in the circuit takes a shortcut route other than the designated one. However, a circuit breaker disconnects the circuit if the current source is unusually high. It protects the printed circuit board from destruction by these short circuits.
Electromagnetic Interference and Static Electricity Protection
The power supply must have a filter that eliminates electromagnetic interference, which may damage the power supply or the entire circuit. In addition, the power supply must have a ground connection that allows any static charges to flow away from the circuit board. Static electricity builds up on the PCB’s surface and may damage the circuit and may cause damage to the power supply too.
Overloading occurs when the circuit draws more power than the power supply can provide. To prevent overloading, the power supply must have a power-limiting circuit that controls the amount of the power supply’s output power.
During their operation, electronic devices tend to have some fever. However, the circuit may get extra hot in extreme cases, affecting its entire functioning. Similarly, the power supply and heat to relatively high temperatures. To avoid overheating, the power supply has a thermal cut-off that detects the circuit is overheating and breaks the circuit.
Reverse Polarity Protection
Reverse polarity occurs when you connect the power circuit to the printed circuit board in the opposite direction. In addition, reverse polarity may damage the circuit components. To avoid such damages, the power supply has a diode that only biases the current in a specific direction. A diode is a device that allows current to pass through in one direction only. Consequently, the circuit components cannot get damaged even in the case of reverse polarity.
Characterization of PCB Power Supplies
We can characterize the PCB according to its physical structure or functionality.
These categories are:
On-board and Off-board power supply
Off-board power supplies are suitable for applications requiring less power and external to the PCB. High-power applications need onboard power supplies, which are in-built into the PCB. In general, low-power applications employ off-board power supplies, whereas high-power applications use onboard power supplies.
Centralized or Distributed Power Supply
A PCB can have a distributed or centralized power supply. While using a centralized power supply, we power all of the gadgets on the PCB from a single power source. On the other hand, a distributed power supply uses several power sources to power the devices on the PCB.
Distributed power supplies are suitable for high-power applications, while central power supplies are typically applicable in low-power applications.
Isolated or Non-isolated Power Supply
PCB power supply comes in both isolated and non-isolated varieties. Isolated PCB power supplies supply electricity to the PCB while separate from the AC power line. Furthermore, connecting the power supply directly to the AC power line makes it a non-isolated power supply. Therefore, compared to non-isolated PCB power supplies, isolated PCB power supplies are more suitable for low-power applications.
Regulated or Unregulated
Regulated PCB power sources supply steady voltage to the PCB. On the other hand, unregulated PCB power supplies deliver fluctuating voltages of electricity to the PCB. Typically, low-power applications employ regulated PCB power supplies, whereas high-power applications use unregulated PCB power supplies.
From the above details, the power supply unit is essential to any electronic system. In addition, all the electronic devices operate in the presence of a driving power. Furthermore, with a reliable power supply, you will have an assurance that your circuit will function properly anytime the power is available. However, several power supplies are compatible with different printed circuit boards. You should therefore choose the power supply unit that best suits your setup.