A controller circuit for a PV module includes a receiver circuit and a mode control and power conversion circuit. The receiver circuit receives a first signal from a transmitter circuit associated with the PV module. The receiver circuit changes a second signal from a first state to a second state based the first signal. The mode control and power conversion circuit receives a DC string voltage from a string of PV cells associated with the PV module, receives the second signal from the receiver circuit, switches from a first mode to a second mode in response to the second signal being changed to the second state, converts the DC string voltage to a standby voltage in the second mode, and provides the standby voltage to DC power lines between the PV module and a DC-to-AC inverter in the second mode.