[Training Camp_Basic Class] DC adjustable power supply design based on LM2596 +486768A

A continuously adjustable USB input and output power supply is designed using the LM2596 step-down chip. The maximum output current of LM2596 is 3A, the ADJ output range is 1.2-37V, the maximum input voltage can reach 40V, and the quiescent current is small. The line width of the input and output must ensure the flow capacity. Considering heat dissipation, windows can be opened behind each chip.

**About the periphery of the chip**, the chip is packaged in TO-263-5, and the output and output are designed with capacitors of appropriate size and quantity. It is necessary to consider whether the withstand voltage value of the capacitor is sufficient; when selecting the inductor; Schottky The diode needs to pay attention to the forward current size. If a load current of 3A is required, the current value of the diode needs to be higher than it. The forward current of the SS56 selected here is 5A. For the selection of the inductor, the following figure can give you a general understanding. For details, please refer to the data. The manual is very specific and clear. There is a Table in the data manual. You can choose the corresponding capacitors and inductors according to your own needs. It is very convenient. If it is ADJ output, try to use a 1% accuracy resistor for R1, which is beneficial to the output. The voltage is close to the calculated value. The example of RP1 below is 10K. If the resistance corresponding to the output voltage you need is greater than 10K, you can choose a larger slip. The calculation formula is as shown in the figure below
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