Many engineers who have not used the design of switching power supplies may have a certain fear of it, such as concerns about interference issues with switching power supplies, PCB layout issues, and the parameters and types of components


Select a question, etc. As long as you understand, using a switching power supply design is still very convenient.


A switching power supply generally includes two parts: a switching power supply controller and an output. Some controllers integrate MOSFETs into the chip, making it easier to use and simplifying the PCB


Design, but the flexibility of design is reduced.


The switching controller is basically a closed-loop feedback control system, so there is generally a sampling circuit for feedback output voltage and a control circuit for the feedback loop. Therefore, the design of this part


The goal is to ensure accurate sampling circuitry, as well as to control feedback depth, because if the feedback loop responds too slowly, it can have a significant impact on transient response capabilities. The output section design includes


The selection of output capacitors, output inductors, and MOSFETs is basically to meet the balance between performance and cost, such as using small inductors at high switching frequencies


Value (meaning small packaging and low cost), but high switching frequencies can increase interference and switching losses on MOSFETs, resulting in reduced efficiency. The result of low switching frequency


The opposite is true. For ESR of output capacitor and Rds of MOSFET_ The on parameter selection is also crucial. A small ESR can reduce the output ripple, but the capacitance cost will increase,


Good capacitors are expensive. The driving ability of switching power supply controllers should also be noted that too many MOSFETs cannot be driven well. Generally speaking, suppliers of switching power supply controllers will provide


The specific calculation formula and usage plan are for engineers to learn from.