3.1.3 Extra Power Supplies

The board supports many add-on boards with various power supply constraints. To satisfy all power requirements of large loads from SODIMM add-ons and M.2 daughter cards, additional power supplies are implemented on the main board, providing additional 3.3V (VDD_3V3_B) and 2.5V rails (VDD_2V5_B).

The MIC23450 is a high-efficiency, 3 MHz, triple 2A, synchronous buck regulator with HyperLight Load® mode and low-output ripple voltage over the entire load range. For more information, refer to www.microchip.com/en-us/product/mic23450.

Figure 3-6. Extra Power Supplies Schematic

If the JP1 jumper is placed on header J2 pins 2-3 (5V_MAIN connected to EN_3V3_2V5_B), it will enable the extra power simultaneously with the system power.

If a low-power consumption is required during PMIC shutdown, JP1 can be moved to 1-2 position of J2 (VDD_3V3 connected to EN_3V3_2V5_B). While the PMIC is in Shutdown mode, the enable pin of MIC23450 is kept low, disabling the 2.5V and 3.3V outputs. This is the default jumper configuration of the kit.

If the jumper is not placed on any position, the R5 resistor keeps the enable pin of MIC23450 low, disabling its outputs.