Smart PCB Design of Boost Converter

The source material for this blog post is from https://www.ti.com/lit/an/slva773/slva773.pdf.

PCB Designs

PCB Layout is a tool of high-level engineering for board design in which intelligent hand routing of high-speed and differential signals, the auto-router that based on shape, developed approval, or a large number of import/export options. For real-time DRC, dip Trace includes a process of design, which detects and reports mistakes as they occur. We can view the board in 3D as well as being produced for CAD modeling in mechanical engineering. Designer’s Rule, net availability validation, and in-depth analysis, and as the finished product are of the highest quality, a comparison to the source schematic ensures. 

The boost converter is the most basic kind of switchable-mode converter. It enhances or increases the voltage input. It all is made up of a capacitor, a microelectronics switch, an inductor, and a transistor. A standard square wave source is also needed. A boost converter is made up of just a few components. A transformer of AC and inductor is much bulky and heavier than it. They’re so simple because they were designed to control aircraft equipment in the 1960s. It was small and possible, so it was very important for these converters. The most significant benefit that boost converters have is their high productivity – some of them can even reach 99 percent. About 99 percent is converted into usable output energy of the input energy, while only 1% is lost, to put it another way. 

Working of the Boost converter

For understanding how a boost converter works, you must first understand how inductors, MOSFETs, transistors, and capacitors function. 

1. The inner voltage transistor is used to charge the capacitor. 

2.  At this step, we turn on the power. The MOSFET is switched on when our signal source gets higher. Through the capacitor, all of the currents are rerouted to the MOSFET. The external capacitor is still fully charged because it can’t discharge via the now back-biased inductor until the inductor delays the current ramp-up. After all, there is no immediate short-circuiting of the power supply. Around the capacitor, a magnetic field forms. You should always remember that the input power all over the capacitor is polarized. 

3.  Now, the inductor’s current is suddenly cut off when the MOSFET is switched off. An inductor’s nature keeps the current flowing smoothly; it doesn’t like quick shifts in current. As a result, it dislikes when the current is instantly turned off. To sustain current flow, using the energy present in the magnetic field, it produces a broad current through the reverse direction of the current gradually transfer to it. We can see the circuit now works as a current source in the sequence with providing current if we ignore the other components of the circuit and focus solely on the polarity signals. Now it shows that the transistor’s anode is distorted and at a high current than the cathode. By placing a higher current on the output capacitor than before, we can increase the DC voltage from a low to a higher level.

How can we make a good PCB design for boost converter?

The simplest method is to copy the boost converter’s configuration from its figure or testing panel, but the design may not be compatible with the system board. For that purpose, we have some steps to make a good PCB design for the boost converter. Here are the following steps:

• Output Capacitor should be placed and routed in the correct location. Although the outer transistor is an essential component of any boost converter, it must be located near the IC. To reduce excessive current, link the transistor to the IC with a short and large trace because the current flow through the outer transistor is pulse-type. 

• The second important thing is the inductor is the next part of being installed. The capacitor has to install close to the IC to minimize radiated EMI. To manage the high current while taking up the least amount of space, the copper in the node should be designed. Although the node is the boost converter’s noisy source, every signal of a sensitive node should be kept at a safe distance. 
• The input capacitor is the final power part of being installed. The input capacitor controls the inner circuit and the under-current circuit. Consequently, the input capacitor’s ground node and IC control ground pin should be kept near. The boost converter’s Power Ground is made up of the input transistor ground node, outer transistor ground node, and IC ground pin. As the input capacitor’s current is constant, the distance between the input capacitor’s node and the inductor is insignificant. Until the VIN voltage is normally constant, a large copper area on the node will not create problems, and heat efficiency will increase due to a large copper area. Though the snubber circuit is critical as the inner capacitor, we install it first. Because the snubber circuit isn’t used in most applications, it won’t be addressed in the following chapters. 

• The digital and logic modules are also used in the small-signal parts. The resistors and capacitors for the pin are the small-signal analog elements for the boost converter. Noise is particularly sensitive to power devices and routers if they have high input impedance, like pins. If the trace is routed close to the node, switch noise can cause problems by coupling to the pin.
• Analog small-signal modules’ ground node and the IC’s pin form a Signal Ground that should be joined to the IC’s Power-Ground with a point. Keep in mind there isn’t any high-voltage current flowing via the Signal-Ground. On the other hand, noise coupling into the control circuit may result in poor output voltage management, an incorrect current cap, and other unusual problem. The Sensor is usually attached to the ground nodes of logic circuits. If they are from the Signal-Ground, they can be linked to Power-Ground. Simply ensure that the logic behavior is unaffected by voltage noise coupling into the logic circuit.

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