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This article shows you what the working principle of Buck circuit is, the content is concise and easy to understand, it can definitely brighten your eyes. I hope you can get something through the detailed introduction of this article.

The so-called Buck circuit, in fact, is the step-down circuit, this topology is very common in DC/DC circuits, we usually use DC/DC chips, such as LM2596,XL7025, are this Buck topology. When using this kind of DC/DC chip, diodes, inductors, capacitors and other key components will be used. The inductor here plays the role of energy storage and the capacitance acts as a filter.

The influence of capacitance and capacitance

If the inductance is too small, it will lead to insufficient energy storage, and when the MOS tube is cut off, the ripple will be too large and the power supply will fluctuate; if the capacitance is too small, the filtering effect is not obvious. Therefore, the selection of inductor and capacitor should be appropriate.

There is a MOS transistor in the Buck circuit, which controls the turn-on and turn-off of the MOS transistor through PWM, which is why it is called switching power supply.

The working principle of Buck Circuit-conduction

This is shown in the following figure. When the MOS tube is turned on, the input voltage is higher than the output voltage, and the current flows through the inductor L18 to supply power to the load Load and back to the negative pole of the power supply. Because the input voltage is higher than the output voltage, the continuous current diode D24 is turned off and the current flows through the inductor L18 to charge it.

The working principle of Buck Circuit-off

This is shown in the following figure. When the MOS tube is turned off, the input current of the power supply is cut off, the direction induction electromotive force (EMF) generated by the inductor L18 hinders the change of the current, and the diode D24 is turned on. At the same time, the electric energy stored by the inductor L18 supplies power to the load, so the inductor, the load and the diode form the loop.

This is how Buck works. The PWM here controls the turn-on / turn-off frequency of MOS transistors. The higher the frequency, the smoother the output voltage; the lower the frequency, the greater the ripple of the output voltage. In order to have a relatively pure voltage waveform at the output end, it is necessary to reasonably select the parameters of inductance and capacitance. If the inductance and capacitance are too small, the output ripple is relatively large; if it is too large, the cost will increase.

The above is how the Buck circuit works. Have you learned the knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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