Maxim Integrated Products, Inc.
Led driver with ability to operate at arbitrarily low input voltages

Abstract:

An LED driver with ability to operate at low input voltages is disclosed. The LED driver comprises a boost converter to boost an input voltage to a desired output voltage to power one or more LED strings. The boost converter incorporates a first controllable switch, such as a metal-oxide-semiconductor field-effect transistor (MOSFET), IGBT, etc., for output voltage control. The boost converter receives input from an external source, such as a battery voltage, as power source for voltage boost operation. The first controllable switch couples to a gate driver powered by a linear regulator, which switchably couples to different voltage sources via a second switch to ensure that the gate driver is able to provide enough voltage for switching the first controllable switch.