Hey! I’m planning to design a pcb for high power Leds, I want to use 12 V fans and a 5v microcontroller (esp32). I would like to make my own buck converter.
So the question is, how do I reduce the voltage from 48 to 12 v and then 5v for the microcontroller using the same 48V 7A power supply?
I was trying to use a 12v adapter and then decrease the voltage to 5v using an LM2596S but it didn’t work (I’m getting 12v on the output). I got the values from Webench power design tool for Texas Instruments.
Here’s the schematic
48 to 12 (4A)
12 to 5 (1A)
I’d like to know if you guys can point me to the right direction please.
I was trying to use a 12v adapter and then decrease the voltage to 5v using an LM2596S but it didn’t work (I’m getting 12v on the output). I got the values from Webench power design tool for Texas Instruments.
Here’s the schematic
What is the peak load current on the 5 V? I've been down this road, and sometimes a switching converter isn't worth the complexity. If the system is not critically dependent on battery life and the 5 V current is low, getting rid of that little bit of extra heat in a linear regulator will save significant development time (which ultimately is paid for by someone), and probably some component cost.
12V to 5V 1A linear will have 7 watts of heat. And draw 1A from a battery.
12V to 5V 1A switcher will have 0.5 watts of heat. And draw 0.4A from the battery.
Note that the max voltage for an ESP32 is 3.6V. A lot of boards have a 3.3v regulator to supply the ESP, however, if you use just a module 5V will destroy it.
As I said, if the 5 V current is low and if battery life isn't an issue ... I missed the "12 to 5 (1A) " note. oops.
Still, if the conditions are right ... I did a 6 kW VME chassis that had lots of aluminum surfaces and a ton of air flow. The system monitor was powered by the +5.1 V, +12 V, and +18 V (specialty chassis), diode-ORed into a 5 V linear regulator at around 1 A.