LED drivers and lighting systems having a dynamically reconfigurable switching network is disclosed. The lighting system comprises a switching network which provides interconnections between LEDs or LED lamps that can dynamically reconfigure between largely parallel circuits and largely serial circuits as the instantaneous voltage of a power supply varies. When the instantaneous voltage of the power source is low, the switching network interconnects the LED lamps in a largely parallel configuration. As the instantaneous voltage increases, the switching network reconfigures and interconnects the LED lamps with increasing serial configurations. As the instantaneous voltage begins to decrease, the switching network reconfigures and interconnects the LED lamps back to a largely parallel configuration.