An LED driver is presented with a sensing circuit and attenuator circuits to provide three-way switched dimming as well as phase-cut dimming to control the output power driving an LED load allowing installation into conventional three-way switched lamp sockets or in sockets wired to a wall or table mounted phase-cutting dimmer control. When installed in a three way socket, the circuit senses the position of the three way switch and changes the lamp current accordingly. The lamp can also be dimmed by a table-top dimmer or a wall dimmer (in a three-way socket or in a conventional dual contact socket) by applying a phase-cut power input, with the driver circuit including circuitry to sense the average value of a phase-cut power line to adjust lamp current.