An LED driver is configured to minimize power consumption during standby operating modes. The LED driver includes power factor correction (PFC) and isolated DC-DC conversion stages, driven by respective first and second regulators. An auxiliary sensor detects environmental conditions for a controller which generates standby or normal operating mode signals based thereon. A low standby isolated power supply circuit receives operating mode signals and is configured: responsive to normal operating mode signals to enable the voltage regulators; responsive to standby mode signals to disable the voltage regulators, and in both modes to supply power to the controller and auxiliary sensor. Accordingly, the controller and auxiliary sensor are continuously enabled whereas the PFC and DC-DC stages of the LED driver are disabled during standby modes. Additional circuitry may selectively disconnect voltage sensing resistance networks from the LED driver for further reductions in power consumption during standby mode.