5 Voltage Regulators

The Multi-Phase Power Board is powered entirely from the V_SUPPLY screw terminal. All required voltages are generated on-board from the main 6-50V supply through a series of regulators.

5.1 Power Domains

There are four power domains in use on the Multi-Phase Power Board.

V_SUPPLY

V_SUPPLY can be from 6V to 50V and is applied to the board via the V_SUPPLY screw terminal. It is the primary power source for the rest of the board and the voltage used to drive the Phase Outputs. This power domain can be measured using a Voltage Monitor.

+5V

V_SUPPLY is stepped down to +5V by a MIC28512 buck regulator. In addition to being a source for the other voltage regulators, +5V is used for:

+12V

The MCP1661 boost regulator generates a +12V output which powers the MOSFET gate drivers in the MOSFET gate drivers in the power stage. This power domain can be measured through a Voltage Monitor.

+3V3

+3V3 is the main logic level of the Multi-Phase Power Board. It is generated by an MCP1754 LDO and used by the following peripherals:

Limits

Table 5-1. Voltage Rail Limits
Domain	V_min	V_max	I_max
V_SUPPLY	6V	50V	30A
+5V	4.81V	5.17V	2A
+12V	11.40V	12.55V	200 mA
+3V3	3.23V	3.37V ⁽¹⁾	150 mA
Note: 1: The +3V3 rail is reverse blocking and tolerant of voltages up to 5.5V.

5.2 Power Status LEDs


The power status section of the MPPB features three LEDs that indicate which of the on-board power domains have a voltage present: +12V Blue LED +5V Green LED +3V3 Yellow LED

5.3 Voltage Monitors

You can monitor the V_SUPPLY and +12V voltage domains on the Multi-Phase Power Board from the adapter connector via fixed voltage dividers.

Table 5-2. Voltage Monitor Connections
Position on Adapter Connector	Net	Divisor
9	V_SUPPLY	16
11	+12V	4

5.4 Voff Functionality


The Voff (Voltage-Off) signal is an open drain output from the Multi-Phase Power Board that indicates whether the MPPB is powered. The signal is held low as long as the +5V rail is present, indicating that the MPPB supplies +3.3V to the Adapter connector. This functionality is used to inhibit other power sources on connected adapters from conflicting with the MPPB’s on-board regulators.

Table 5-3. Voff Connection
Position on Adapter Connector	Silk Screen Marking
38	VOFF