preamble
Power supply circuit design is important, in order to better give the people who have the need for hardware design, the basic process of power supply design is described.
Immediately after the previous 12V to 5V, this design commonly used 12V to 3.3V circuit, not commonly used 12V to 4V circuit.
12V to 3.3V Circuit
Step 1: Applying a Typical Circuit
(Depending on the difference between the base plate and the typical circuit, the inductance and capacitance are in the range of 3.3~5V, we can not adjust)
Step 2: Adjust the output voltage
The output voltage of the TPS54331 device can be externally regulated through a resistive voltage divider network.
3.3V = 0.8V x ( R5/R6 + 1)
R5/R6 + 1 = 3.3/0.8
R5/R6 = 4.125 - 1
R5/R6 = 3.125
Since the resistance value is chosen to be a high precision 1% resistor and then preferably standardized, it is possible to view theHardware Practical Tips: Resistor Accuracy and Common Resistance Tables", the resistance values R6 are chosen to be 20KΩ and R5 to be 105KΩ.
Typical circuit: 10.2/3.14 = 3.14, tried a few really couldn't find a ratio that close, so this is it.
12V to 4V Circuit
Step 1: Applying a Typical Circuit
Step 2: Adjust the output voltage
The output voltage of the TPS54331 device can be externally regulated through a resistive voltage divider network.
4V = 0.8V x ( R5/R6 + 1)
R5/R6 + 1 = 4/0.8
R5/R6 = 5 - 1
R5/R6 = 4
As the resistance value selects a high precision 1% resistor, and then preferably a standard one, you can check the "Hardware Practical Tips: Resistor Precision and Common Resistance Values Table", and select the resistance value R6 as 9.1KΩ and R5 as 36.4KΩ.
36.5 KΩ/9.1 KΩ=4.010
39 KΩ/9.76 KΩ=3.995
80.6 KΩ/20 KΩ=4.030
(Depending on the difference between the base plate and the typical circuit, the inductors and capacitors can be left unadjusted in the 3.3~5V range).
Automatic numbering of schematic diagrams
It's all numbered.
Output schematic
Conduct a review.