Status: Active
Owner: Nolan Haines
Initial Requirements:
12V-5V @ 3A Buck Converter Board -
12V-5V Synchronous Buck Converter PCB @ 3A Max Load Current Consumption (15W)
I/O:
Input Voltage Connector
+12V
GND
Output Voltage Connectors (2x)
+5V
GND
Current Sense Connector
V_sense+ and V_sense-, or:
I_sense and GND
Features:
12V-5V Buck Converter @ 3A
Reverse Polarity Protection
Status LEDs for both +12V and +5V voltage rails
Optional current sense interface
Documentation:
*NOTE: The numbers for the components below does not correlate with the typical application circuit above. Please refer to the altium schematic for this board for the correct numbering.
Capacitors:
C1 & C2, C2, C5, C6, C7, C8, C9, C10: https://www.digikey.ca/en/products/detail/murata-electronics/GRM188R61E106KA73J/9887674
Voltage rating is 25V which will suffice for this application as the maximum will be 12V. We want a voltage rating of 2 to 3 times the voltage at the node. In the datasheet they recommend C1 to be 10uF for any application of this IC.
C3 & C7C4: https://www.digikey.ca/en/products/detail/samsung-electro-mechanics/CL10B104KA8NNNC/3886664
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https://electronics.stackexchange.com/questions/170957/de-coupling-capacitor-and-bulk-capacitor
C8 & C9: https://www.digikey.ca/en/products/detail/samsung-electro-mechanics/CL21A226KOQNNNG/3894433
The capacitance value for C8 and C9 is 22uf each, adding up to 44uf. We chose this value because it is compliant with the datasheet as the capacitance total for C8 & C9 should be 20<x<68. These are bulk capacitors, which were described above.
These act as bulks caps as the magnetic field created from the inductor will store energy and is used to provide a safety net of current once charged to prevent the output supply to drop or increase when current is not available.
Resistors:
R1: https://www.digikey.ca/en/products/detail/bourns-incyageo/CR0603RC0603FR-FX-5492ELF/3784088?s=N4IgjCBcoEwAwA4CsVQGMoDMCGAbAzgKYA0IA9lANohIAsAdAJwAEA1gPIAWAtviALqkADgBcoIAKoA7AJYj2mALKFs%2BAK4AnQiAC%2BpALS1UIDJBwES5KuAQA2ZAJ1OgA0754K9L/727298
Reasoning is in the table of the datasheet. For an output voltage of 5V, they recommend the resistance to be 54.9k ohm.
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