The present invention discloses a high speed programmable electronic current driver circuit for supplying a controlled modulated current to an LED comprising: a current driver operable over a selectable range of current levels for connection to an LED for supplying operating current to an LED; control means connected to the current driver to select the current level for operation of the current driver; transmission gating means connected to the current driver to gate high speed data signal pulses to the current driver to modulate the current of the current driver by the data signal pulses by gating the current of the current driver with the data signal pulses; whereby light output by the LED will be modulated by the data signal pulses at selectable current levels.

A method for driving a light emitting diode coupled to an output of a current mirror is provided. The method includes providing a control terminal voltage of the current mirror as a reference voltage, increasing a voltage of an input of the current mirror and providing an input of the light emitting diode as a voltage feedback point for keeping a constant voltage difference between the input and the output of the current mirror, and driving the light emitting diode by a voltage at the output of the current mirror.

A driver circuit and a method drive an electronic component such as a laser diode with a variable electric current that is controlledly switched between at least two discrete current levels. The driver circuit includes circuit elements that damp ringing or initial transient oscillations that arise when switching the current between the current levels. The driver circuit includes a current mirror having a mirror amplification factor dependent on the frequency of the variable electric current. In order to counteract parasitic capacitances and/or inductances leading to the ringing, an inductance and/or a resistance are connected between the two series circuits making up the current mirror, a capacitance is connected parallel to a reference resistor of one of the series circuits, and/or a capacitance is connected across the voltage supply.

An LED driver drives a plurality of light emitting diodes (LEDs) having first terminals connected to a common output stage and second terminals respectively receiving different, suitably rectified, phases of a sinusoidal signal. An output stage of the LED driver includes a first bipolar transistor coupled between a first supply terminal and the first terminals of the LED's. A first MOS transistor drives the base of the first bipolar transistor. The gate of the first MOS transistor is coupled to a first reference voltage. A second bipolar cascode transistor is connected in series with the first MOS transistor and biased by a second reference voltage such that the voltage across the first MOS transistor does not exceed a limit value.

A controlling apparatus for controlling a plurality of LED strings and related light modules is disclosed, wherein each of the plurality of LED strings has a first terminal being electrically connected to an operating voltage. The controlling apparatus includes: a plurality of transistors, each having a control terminal, a first terminal, and a second terminal, wherein the first terminal of each transistor is electrically connected to a second terminal of a corresponding string of the plurality of LED strings, and the second terminals of the plurality of transistors are respectively grounded through a plurality of impedance elements; and a transistor controller, electrically connected to the control terminals of the plurality of transistors, for controlling a current of the first terminal of each transistor by adjusting an input signal of the control terminal of the transistor according to a voltage at the second terminal of the transistor.