Abstract: In a method for producing a control signal for regulating a drive current for driving an LED, a current through the LED is sensed, wherein the LED is driven by a power converter output, and wherein an output voltage of the power converter is proportionately controlled by a control signal. Next, a power supply voltage is sensed. The control signal is produced for the power converter, wherein the control signal is proportional to a difference between a reference voltage and the current through the LED. The control signal is then offset in response to the power supply voltage to reduce the current through the LED as the power supply voltage drops.

Abstract: In a method for producing a control signal for regulating a drive current for driving an LED, a current through the LED is sensed, wherein the LED is driven by a power converter output, and wherein an output voltage of the power converter is proportionately controlled by a control signal. Next, a power supply voltage is sensed. The control signal is produced for the power converter, wherein the control signal is proportional to a difference between a reference voltage and the current through the LED. The control signal is then offset in response to the power supply voltage to reduce the current through the LED as the power supply voltage drops.

Abstract: In a method for producing a control signal for regulating a drive current for driving an LED, a current through the LED is sensed, wherein the LED is driven by a power converter output, and wherein an output voltage of the power converter is proportionately controlled by a control signal. Next, a power supply voltage is sensed. The control signal is produced for the power converter, wherein the control signal is proportional to a difference between a reference voltage and the current through the LED. The control signal is then offset in response to the power supply voltage to reduce the current through the LED as the power supply voltage drops.

Abstract: A ballast circuit and method for operating a lamp includes a lamp preheat/ignition circuit for preheating and igniting the lamp. A ballast controller integrated circuit is operatively connected to the preheat/ignition circuit wherein the lamp preheat/ignition circuit is operatively controlled in a a) preheating mode wherein the lamp is preheated at a preheating frequency for a predetermined period of time; b) a user programmable intermediate ignition mode wherein the lamp is heated at an intermediate ignition frequency that is lower than the preheating frequency; and c) an operating mode wherein the lamp is operated at a final operating frequency that is lower than the intermediate ignition frequency.

Abstract: A ballast circuit and method for operating a lamp includes a lamp preheat/ignition circuit for preheating and igniting the lamp. A ballast controller integrated circuit is operatively connected to the preheat/ignition circuit wherein the lamp preheat/ignition circuit is operatively controlled in a a) preheating mode wherein the lamp is preheated at a preheating frequency for a predetermined period of time; b) a user programmable intermediate ignition mode wherein the lamp is heated at an intermediate ignition frequency that is lower than the preheating frequency; and c) an operating mode wherein the lamp is operated at a final operating frequency that is lower than the intermediate ignition frequency.

Abstract: A ballast compatible with different types of gas discharge lamps includes a power supply and a controller connected to the power supply. The controller includes a memory having a plurality of desired operating parameters stored therein for respective different types of gas discharge lamps. A sensing circuit causes the power supply to supply a current to the gas discharge lamp prior to start-up and senses a voltage based thereon indicative of a type of the gas discharge lamp. A control circuit causes the power supply to provide the desired operating parameters based upon the type of gas discharge lamp. Since the desired operating parameters are applied to the gas discharge lamp, the life of the lamp is increased.

Abstract: A ballast compatible with different types of gas discharge lamps includes a power supply and a controller connected to the power supply. The controller includes a memory having a plurality of desired operating parameters stored therein for respective different types of gas discharge lamps. A sensing circuit causes the power supply to supply a current to the gas discharge lamp prior to start-up and senses a voltage based thereon indicative of a type of the gas discharge lamp. A control circuit causes the power supply to provide the desired operating parameters based upon the type of gas discharge lamp. Since the desired operating parameters are applied to the gas discharge lamp, the life of the lamp is increased.