Electronic – Multiple Step-Down Voltage Rails from a single DC Power Supply

buckcircuit-designpower supplyswitch-mode-power-supplyvoltage-regulator

I have one working PCB which has three different Voltage Rails: 3.3V, 4V and 1.8V. They are generated using three separate step-down buck converters. The input voltage to all the converters is a single DC Power Supply (12V).

  • Buck Converter Generating 4V powers 4G LTE Module (Load 2.5A)
  • Buck Converter generating 1.8V powers LoRa IC SX1301 (Load 1A)
  • Buck Converter generating 3.3V powers iMX6ULL System-on-module (Load: 3A)

enter image description here

These three different buck converters are occupying alot of PCB space and increasing the BOM. I am thinking to implement single IC solution for my system. A quick google search landed me on two solutions.

  • A Triple Step-Down Converter from TI (TPS6526x)
  • Using a single Buck Converter to generate multiple voltages. (The link is over here).

What should I consider? Is there any different solution other than listed above?

EDIT:
The LoRaWAN IC is SX1301 and it requires 1.8V power supply.

Best Answer

The triple converter gets you some space savings while maintaining the basic simplicity of buck regulators. However, the chip now is a single point of failure. Multiple outputs from one switching stage will save more space. However, the magnetics no longer are simple inductors so the added design and development time might eat up or exceed the BOM savings. Unless you're talking about high volume, I'd go with a triple controller. I prefer Linear Tech, but TI should be fine.

Related Topic