What is a Boost circuit?

I believe many people have come into contact with circuits, but do you know what a boost circuit is? For laymen without any electrical foundation, Buck and Boost circuits can change the voltage back and forth, which is very magical. The most amazing thing is that the Boost circuit can boost the voltage. Want to know how it's done?

For the simplest Boost circuit, it can consist of only five components: power supply, inductor, capacitor, diode and a switch. If we connect an inductor or a capacitor individually to both ends of the power supply, they can store electrical energy in various forms, and our story begins here:

When the inductor is connected to both ends of the power supply, current flows through the inductor. This process will generate an induced magnetic field around the inductor. When the current stabilizes, its magnetic field also tends to be stable. If we remove the power supply, the magnetic field will generate an electromotive force in the opposite direction in the circuit, and its value may be greater than the electromotive force of the original power supply. After understanding these two points, the most basic principles of the Boost circuit are not difficult to analyze.

In such a circuit, if we close the switch, the power supply charges the inductor and the electrical energy is converted into magnetic field energy on the inductor. And when we turn on the switch, the magnetic field on the inductor will be converted into electrical energy, charging the capacitor through the diode on the right. For the capacitor, its voltage will depend on the power supply voltage and the charging process of the inductor. When the switch is turned on, it is powered by not only the power supply but also the energy in the inductor, so its voltage will be higher than the original power supply voltage. If this process continues back and forth, we can get an output voltage higher than the supply voltage across the capacitor.

Obviously, in the actual power supply, it is impossible for us to press the switch with our hands. The switch tube will be used in this position. It will switch on and off extremely quickly, thereby controlling the entire process. This is also the origin of the word "switch" in switching power supplies. The above is an introduction to the Boost circuit. I hope it will be helpful to designers.