Patent ID: 9013110
Filing Date: 2015-04-21
Classification: H05B

Abstract:
1. A method of driving a string of light emitting elements, the method comprising: applying a PWM drive signal to circuitry that regulates a voltage appearing at a source of a transistor, wherein a drain of the transistor is coupled to one end of the string of light emitting elements and wherein the source is coupled to ground through a resistive element; and controlling sequencing of the PWM drive signal for the string of light emitting elements and a voltage supply signal for the light emitting elements such that the voltage supply signal starts to increase from a low voltage before the transistor is turned on, but is not increased above a predetermined allowable voltage for the transistor until the transistor is turned on, and such that the voltage supply signal starts to decrease from a high voltage before the transistor is turned off, but is not decreased below the allowable voltage for the transistor until the transistor is turned off.