PCB Layout Of The Power Circuit

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The power circuit is a crucial component of an electronic product, and its design directly impacts the product's performance. Our electronic products primarily utilize linear power supplies and high-frequency switching power supplies.

In theory, a linear power supply provides the same amount of current that the user requires at the input end. In contrast, a switching power supply delivers the necessary power to meet the user's demands. Generally, a linear power supply functions as a series-regulated power supply, where the output current equals the input current. It is essential to clarify both the magnitude and the direction of current flow to ensure the board is designed correctly.

When designing a PCB, the component layout should be compact, and all connections must be as short as possible. Components and wiring should be arranged based on the functional relationships present in the schematic diagram.

While designing the linear power supply PCB, attention must also be given to the heat dissipation of the power regulator chip. Heat generation occurs due to voltage drops; for instance, with a 5V drop, the heat generated is 2.5W. If the input voltage is 15V and the voltage drop is 10V, the heat produced is 5W. Therefore, it’s vital to provide adequate cooling space or reasonable cooling fins. Linear power supplies are typically suited for applications with relatively small voltage and current differences; otherwise, a switching power supply should be utilized.

PCB Layout Of The Power Circuit

The switching power supply operates by controlling a switching tube to turn on and off quickly, generating a PWM waveform. It adjusts voltage through electromagnetic power conversion using an inductor and a freewheeling diode. The switching power supply is known for its high power, efficiency, and low heat generation. Common circuits employed include LM2575, MC34063, and SP6659. The theoretical principle behind a switching power supply is that power at both ends of the circuit is equal, with voltage and current being inversely proportional.

In designing the switching power supply PCB, several key factors must be addressed, including the feedback line's lead-in point and the freewheeling diode's function. As illustrated in Figure 3, when U1 is activated, the current I2 flows into inductor L1. It is essential to understand that current cannot suddenly appear or disappear in an inductor; it changes gradually over time. During the process, the pulse current I2 flowing through the inductor converts some electric energy into magnetic energy, causing the current to increase. When the control circuit U1 turns off I2, the current cannot vanish suddenly. At this point, the diode activates to replace current I2; hence, it's referred to as a freewheeling diode. This diode allows the freewheeling current I3 to flow from the negative terminal of C3 through D1 and L1 to the positive terminal of C3, resembling a water pump that utilizes the inductor's energy to boost the voltage of capacitor C3.

Another consideration is the introduction of the feedback line for voltage detection. The feedback must occur after filtering; otherwise, the output voltage ripple will be significant. These two aspects are often overlooked by PCB designers, who mistakenly believe that the connection points are interchangeable. In reality, different connections can greatly impact performance.

We emphasize understanding the principles outlined in the schematic diagram because it contains vital information for PCB design, such as component pin access points and the current size at node networks. By thoroughly analyzing the schematic diagram, PCB design becomes much more manageable. When creating a PCB, you can directly follow the layout and wiring of the relevant schematic diagrams. However, as products and circuit boards vary, adjustments should be made according to the specific situation.

Why Choose China PCBA Supplier KSPCBA as Your PCB Layout Of The Power Circuit Manufacturer?

– Experienced and skilled team

– State-of-the-art equipment

– Strict quality control

– Excellent customer service

– Competitive price