Abstract: In some embodiments, a circuit is provided that includes (1) a plurality of light emitting diode (LED) strings coupled to each other in series; (2) a power supply circuit coupled to a first LED string of the plurality of LED strings; (3) a feedback circuit coupled between a second LED string of the plurality of LED strings and the power supply circuit; and (4) a current steering circuit coupled to the first LED string of the plurality of LED strings and further coupled to the second LED string of the plurality LED strings. The current steering circuit includes a plurality of switchable conductive pathways.

Abstract: In an embodiment, a lamp control circuit is provided. The lamp control circuit includes an intermediate current steering block configured to be coupled to a cathode of a first light-emitting device of a plurality of light-emitting devices and a final current steering block configured to be coupled to a cathode of a final light-emitting device of the plurality of light-emitting devices. The final current steering block is configured to disable the intermediate current steering block and conduct current when a voltage input to the plurality of light-emitting devices is sufficient to activate all of the plurality of light-emitting devices.

Abstract: An LED lamp control circuit directly drives an array of series or parallel connected LEDs with current directly derived from the rectified AC voltage. Electrolytic capacitors are eliminated, and the circuit is independent of forward bias voltage of the LEDs, which vary by lot and manufacturer. For example, in an embodiment, an light-emitting diode (LED) lamp control circuit includes a transistor, an LED load comprising one or more LEDs, a power storage device configured to provide power to the LED load, and a controller circuit configured to control the transistor to charge and discharge the power storage device based on sensed voltages of a first node and a second node and a current passing through the power storage device. The power storage device and the LED load are arranged in parallel between the first node and the second node. A voltage source is coupled to the first node and a first terminal of the transistor is coupled to the second node. A second terminal of the transistor is coupled to ground.

Abstract: In an embodiment, a lamp control circuit is provided. The lamp control circuit includes an intermediate current steering block configured to be coupled to a cathode of a first light-emitting device of a plurality of light-emitting devices and a final current steering block configured to be coupled to a cathode of a final light-emitting device of the plurality of light-emitting devices. The final current steering block is configured to disable the intermediate current steering block and conduct current when a voltage input to the plurality of light-emitting devices is sufficient to activate all of the plurality of light-emitting devices.

Abstract: An LED lamp control circuit directly drives an array of series or parallel connected LEDs with current directly derived from the rectified AC voltage. Electrolytic capacitors are eliminated, and the circuit is independent of forward bias voltage of the LEDs, which vary by lot and manufacturer. For example, in an embodiment, an light-emitting diode (LED) lamp control circuit includes a transistor, an LED load comprising one or more LEDs, a power storage device configured to provide power to the LED load, and a controller circuit configured to control the transistor to charge and discharge the power storage device based on sensed voltages of a first node and a second node and a current passing through the power storage device. The power storage device and the LED load are arranged in parallel between the first node and the second node. A voltage source is coupled to the first node and a first terminal of the transistor is coupled to the second node. A second terminal of the transistor is coupled to ground.

Abstract: Circuitry, which is compatible with incandescent light dimmers, is disposed within the screwbase of a compact fluorescent light, and sets driving frequencies for a mercury plasma, based, at least in part, on sensing the duty cycle of the incoming AC supply waveform. In this way, existing lighting infrastructure, including phase-cut dimmer circuits for incandescent light bulbs, may be preserved, and incandescent bulbs can be replaced with compact fluorescent lights equipped with circuitry in accordance with the present invention. In a further aspect, the circuitry synchronizes the bulb drive signals with the AC power line frequency.

Abstract: Manufacturing and/or operational variations that affect performance of an integrated circuit (IC) are at least partially compensated for, by determining the magnitude of these variations and providing one or more corresponding control signals to a voltage regulator, which, responsive thereto, increases or decreases the magnitude of the output voltage. The output voltage of the voltage regulator is typically provided to a power supply node of the IC. Similarly, the output of the voltage regulator may be provided to a substrate portion of the IC, so as to provide a substrate bias that is variable in response to changes in the performance of the IC.