Patent ID: 8339063

Claim:
A driving circuit, comprising: a first inductor coupled in series with a light emitting diode (LED) light source and for providing power to said LED light source; a controller operable for controlling a switch coupled to said first inductor, thereby controlling a current flowing through said first inductor; a current sensor coupled to said first inductor and operable for providing a first signal indicative of said current flowing through said first inductor, regardless of whether said switch is on or off, wherein said switch is controlled according to said first signal; a second inductor magnetically and electrically coupled to said first inductor and operable for sensing an electrical condition of said first inductor, wherein said first inductor and said second inductor are electrically coupled to a common node between said switch and said first inductor, wherein said common node provides a reference ground for said controller, and wherein said reference ground is different from the ground of said driving circuit; a filter coupled to said current sensor and operable for providing a second signal indicative of an average current flowing through said first inductor; and an error amplifier operable for generating an error signal based on said second signal and a reference signal indicative of a target current level, wherein said switch is turned off if a voltage of said first signal increases above a voltage of said error signal.