What Is a Power Supply Board?
A power supply board is a component responsible for providing the specific voltage and current required by the circuits within a device. It ensures that the electrical specifications are met accurately for the equipment’s proper functioning.
Typically, a power supply circuit is designed to accept 100 V AC commercial power and convert it into the DC voltage needed by the device’s internal circuits. The required DC voltage often ranges from 3.3 V to 48 V, varying with the equipment. Additionally, the power supply board aggregates the necessary current values.
Using a general-purpose power supply board as a finished component, instead of designing a customized one for each device, offers significant value. This approach allows cost reduction by standardizing a few power supply board types and manufacturing them in bulk, leveraging the expertise of engineers specializing in power supply circuit design.
Uses of Power Supply Boards
Power supply boards are integral to various equipment types, including industrial machinery, information processing devices like computers and servers, home appliances such as TVs and refrigerators, and audio-visual components like recorders and audio systems.
As devices become more advanced and equipment miniaturizes, the space allocated for power supply circuits is increasingly limited, demanding compact, high-performance, and efficient power supply boards. The growing need for specialized power supply boards, coupled with the cost benefits over in-house design, is evident.
Principle of Power Supply Boards
Power supply boards are categorized into AC/DC and DC/DC types, converting AC to DC voltage, and modifying DC voltage levels, respectively.
1. AC/DC Power Supply Boards
These boards typically convert 100 V AC commercial power into the specific DC voltage required by a device’s internal circuits.
2. DC/DC Power Supply Boards
These boards adjust the DC voltage obtained from the equipment, either increasing (boosting) or decreasing (stepping down) it to match the requirements of the internal circuits.
In addition to voltage conversion, many power supply boards incorporate protective features such as overcurrent and overvoltage protection circuits. These safeguards prevent excessive current flow and overheating in the circuits. Most power supply boards comply with various safety standards to prevent hazards like heat generation and ignition due to incorrect equipment use.
Other Information on Power Supply Boards
1. Benefits of Power Supply Boards
A significant benefit of power supply boards is their ability to reduce EMI (Electromagnetic Interference) noise. This is achieved by short wiring of the noise-prone DC-DC converter IC, coils, and capacitors, and an optimized structure that effectively minimizes noise. Short wiring is crucial as it prevents the amplification of noise that occurs when wiring acts as an antenna.
2. Types of DC-DC Converter Operation
DC-DC converters operate in two main modes:
Linear Regulators:
These regulators achieve the desired output voltage by dividing the input voltage across loads. The division ratio is modifiable using a transistor or similar component as a variable resistor. While they are low in energy conversion efficiency and lose power through the voltage dividing resistor, linear regulators have the advantage of emitting low electromagnetic noise.
Switching Regulators:
Switching regulators generate a pulse wave from the input voltage by toggling switch elements on and off, which is then smoothed at the output. The voltage is controlled by altering the on/off ratio. These regulators are highly efficient in energy conversion but produce higher noise during the switching process.