What factors need to be considered in PCB power supply design?

Have you ever thought about how to transfer energy inside the pcb to power our appliances? There are too many tiny components on a PCB board, and it takes great skill, time and energy to design such a complicated power supply to power each component. Moreover, with the increase in circuit design density and complexity, the complexity of the design is also increasing. Only a perfect power supply design can overcome this challenge. However, for a perfect design, all possible problems need to be dealt with. Some of the issues that need to be resolved include electromagnetic interference, component selection, reducing current loops, and tracking design to handle large currents. In addition, many important parameters such as voltage, current and heat loss also need to be considered.

Let's take a look at the five most important considerations for PCB power connector design.

1.Choose the right regulator
You need to choose from two types of power regulators-linear and switch mode. Linear regulators can provide low noise output, but high heat dissipation, which requires a cooling system. They require an input voltage higher than the required output voltage, and high heat dissipation will reduce efficiency. On the other hand, switch-mode regulators are efficient in a large current range because they temporarily store energy in the inductor and then release the energy at different voltages at different switching times, thereby converting one voltage into another. . This switching noise can cause response peaks.

2.Thermal management
When current passes, heat is released, but this heat depends on the power level, impedance, and characteristics of the component. A well-chosen regulator can reduce this heat dissipation. In addition, it is necessary to ensure that the electronic circuit works at a lower temperature to improve efficiency, which can be achieved by using appropriate cooling methods. These may include radiators, fans, thermoelectric coolers, and thermal vias. Heat sinks are best used with linear regulators; thermal vias can be used near high power rated components; or fans can be incorporated into the design to ensure forced cooling.

3.Choose the correct capacitor
Capacitors are used to provide short peaks in the current demand of the device. Decoupling can reduce the impedance between power and ground. Therefore, the decoupling capacitor acts as a secondary power source, providing the current required by the circuit. The bypass capacitor is another option, it can bypass the noise and reduce the fluctuation of the power bus.

4.Power integrity
The power integrity of the power supply design should be guaranteed, which is the quality of the power delivered to the circuit. Power integrity is to measure the effectiveness of power transmission to the load in the system, to ensure that the circuit and equipment get the appropriate power, so as to achieve the expected performance of the circuit. In order to achieve such power integrity, simulation tools are needed to manage power supply noise. These tools can estimate voltage drops, identify high currents in circuits, and recommend the placement of decoupling capacitors.

5.Frequency response
When the power supply changes from no load to full load, the voltage output will drop briefly before returning to normal voltage. The output may also oscillate for a period of time before the voltage returns to normal. If these oscillations exceed the limit, then adjusting the output capacitor and compensation capacitor becomes very important. These oscillations may also occur when the power supply changes from full load to no load. In order to better respond to this, you must ensure that the selected components are within the design constraints. However, AC and DC circuits should be considered separately.

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