3.3.6 Power Supply System

The PL360G55CF-EK board can be powered by several power sources. Supply the board via:
  • the DC jack 2.0 mm connector J8, DC_IN, with a DC source from 6V to 30V (±5%) and 4.2W
  • USB connector (+5V), J4
  • the power supply pin (+5V) of mikroBUS standard
Table 3-13. Power Sources for PL360G55CF-EK Board
Power Input Voltage Requirements Power Requirements Connector Marking
DC Jack connector +6V to +30V (±5%) 4.2W DC_IN
Target USB +5V According to USB specifications USB
mikroBUS Power pin (+5V) +5V According to mainboard specifications +5V
The PL360G55CF-EK board has two voltage rails:
  • +3.3V for the digital part of the PLC modem, PL360, and the SAMG55J19 MCU
  • +12V to power the class-D amplifier of the PLC coupling circuit
CAUTION: Note that the PL360G55CF-EK board does not provide a power supply protection circuit; only a TVS diode is used to protect from voltage spikes at the DC rail.

The 12V voltage rail is obtained from the Microchip MC16301 buck-boost converter. For a further description about the buck-boost converter see the MCP16301 Buck-Boost Converter User's Guide. If the VDC voltage is always higher than 12V, it is possible to improve the power efficiency by transforming the converter mode from buck-boost to buck, see MCP16301 datasheet for a further explanation.

Figure 3-12. 12V Voltage Design
Restriction: Note that some power sources, such as USB port and mikroBUS rail, might have limited current capabilities and they could not supply enough current for the class-D amplifier transmitting against low impedance values. In this case, an external AC/DC power supply with enough current rating is recommended to maintain the PLC performance at its best. If using one, we recommend a module complying to national regulations or CISPR 32:2015.

Another buck converter, MC16301, is used to generate a regulated 3.3V voltage rail required by the PL360 modem and the SAMG55J19 MCU. For a further description about the buck converter see the MCP16301 Buck Converter User's Guide.

Figure 3-13. 3.3V Buck Converter Design

There are one LED and two test points on each voltage rail to check whether all power supplies are operating properly.

To avoid on board self-generated disturbances within the PLC signal band, both converters are switching at 500 kHz fixed frequency, out of the PLC band (35 to 472 kHz).

Tip: If choosing a different SMPS in the customer design, it is important to analyze its potential interference on the PLC frequency band.
Attention: To avoid noise interferences, the switching frequency of the SMPS must be out of the PLC band and preferably in frequencies above it to avoid harmonics influence. This is essential to obtain a good reception performance.