US 2014/0191684 A1 · SYSTEMS AND METHODS FOR A HYSTERESIS BASED DRIVER USING A LED AS A VOLTAGE REFERENCE

Abstract

The present disclosure is directed to a hysteresis based driver that incorporates the forward voltage of the LEDs being driven into the design of the driver itself. Instead of providing a typical fixed voltage reference, the forward voltage of one or more LEDS driven by the driver is used as a voltage reference. As the input voltage varies during operation of the one or more LEDs, the current varies as well. This current change is larger than it would be without the LEDs and only resistors. This variable current measurement may be used as input into a hysteresis circuit that controls the switch that turns on and off the one or more LEDs. As such, the driver may not incorporate or use a typical fixed voltage reference such as one provided by a zener diode.

Claims20

Dependent claims

A driver for one or more light emitting diodes (LEDs) that incorporates forward voltage of the one or more LEDs to provide hysteresis, the driver comprising:

a first input to receive an input voltage;
a switch electrically coupled to the first input and electrically coupled to one or more light emitting diodes (LEDs), an output of the switch, when switched on, to provide voltage to the one or more LEDs;
a current measurement component electrically coupled to the one or more LEDS, to measure current through the one or more LEDs based on forward voltage of the one or more LEDs;
a hysteresis component to receive as input the input voltage and a measurement of voltage based on the current measured by the current measurement component;
wherein the current measurement component is configured to measure changes to the current based on changes to the forward voltage of the one or more LEDs;
and
wherein the hysteresis component is electrically coupled to the switch to turn the switch off and on responsive to changes to the input voltage in conjunction with the changes to the forward voltage of the one or more LEDs, as measured by the current measurement component, being above or below a threshold.

4 more elements

A driver for one or more light emitting diodes (LEDs) that automatically provides varying frequency, the driver comprising:

a first input to receive an input voltage;
a switch electrically coupled to the first input and electrically coupled to one or more light emitting diodes (LEDs), an output of the switch, when switched on, to provide voltage to the one or more LEDs;
a measurement component electrically coupled to the one or more LEDs, to measure current through the one or more LEDs based on changes to the input voltage;
a hysteresis component to receive as input the input voltage and a measurement of voltage responsive to the current measurement component;
wherein the measurement component is configured to measure a voltage output from the one or more LEDs;
wherein the hysteresis component is electrically coupled to the switch to turn the switch off and on responsive to the changes to the voltage output, the voltage output to increase with a lesser effect than changes to the input voltage;
and
wherein the driver is configured to have times the switch is on vary based on changes to the input voltage.

5 more elements

Dependencies are inferred from the claim text.

Systems and methods for a hysteresis based driver using a led as a voltage reference

Life of this patent

Systems and methods for a hysteresis based driver using a led as a voltage reference

Life of this patent

Abstract

Claims20