In a stacked, parallel configuration, the PG signal is used to communicate between the devices. During device initialization, all devices in the stack pull the PG signal low. After each device completes the initialization, only the Primary device controls the PG signal and holds it low until soft start is completed.

The Secondary devices monitor the voltage level of the PG signal. When the PG signal is low, the secondary devices can not sink current until the primary device releases the PG signal. The external pullup resistor pulls PG high and the secondary devices operate in FPWM from that point onwards.

In case of a fault condition, the secondary device does not drive the PG signal but uses the EN pin to deactivate the whole stack. In this case, the Primary converter pulls the PG signal low. For details, see Table 7-6.