2.3.5 Output Voltage Setting, Feedback and Remote-Sense Configuration:

The output voltage can be set using either the external VOUT-to-FB resistor-divider network or digitally through the VOUT_COMMAND register via I²C/PMBus. For resistor-divider based output-voltage programming, refer to the output-voltage setting (Section 2.5) in the MCPF1525M06 datasheet.

In this reference design, each module uses a separate VOUT-to-FB feedback network connected to its respective VFB pin (pin 13)

U1 Host: Feedback should sense the desired regulated output node.
U2 Client: Feedback may sense directly from the local module output.
The Host and Client feedback networks must remain separate for proper parallel operation.

For parallel operation, the Host and Client modules must be configured for the same VOUT setpoint. There can be a difference of up to 200 mV between the Host and Client which can be compensated by the current-share bus.

When changing VOUT dynamically, update the Host module first, followed by the Client module, using steps of less than 200 mV. For changes greater than 200 mV, apply multiple successive steps.

The reference design also supports remote output-voltage sensing. To regulate at a remote load node, populate R3 and R14, and connect the remote sense points across TP4 (Remote Sense VOUT) and TP6 (Remote Sense GND).

Note: When using VOUT_COMMAND, the command value sets the FB regulation voltage, not VOUT directly; therefore, any hardware feedback-divider gain must be included when calculating the command value.