An LED driver circuit has a rectifier circuit including a first input terminal coupled to a first AC voltage line and a second input terminal coupled to a second AC voltage line. The rectifier circuit is configured to convert a first AC voltage on the first AC voltage line and a second AC voltage on the second AC voltage line to a DC voltage. The driver circuit has a switching circuit coupled to the first AC voltage line and to the second AC voltage line and configured to generate a reference AC voltage based on the first AC voltage and the second AC voltage. The driver circuit has a power management circuit configured to provide a current or power to an LED lamp based on the generated AC reference voltage. The driver circuit has a power supply circuit configured to provide a constant current or power to the power management circuit.