Patent ID: 7999495

Claim:
An electronic ballast with dimming control from power line sensing for a fluorescent lamp, comprising: a line switching sensing circuit, used to generate a switching sensing signal by performing a voltage comparison operation on a DC voltage, and generate a reset signal by detecting the instance when a filtered DC voltage falls below a reset threshold level, wherein said DC voltage and said filtered DC voltage are derived from a main input voltage rectified from a power line, and said reset threshold level is above a minimum operation voltage of said electronic ballast; an oscillating signal gating unit, used to gate an oscillating signal with a pulse signal to generate a gated oscillating signal, wherein a pulse width of said pulse signal is generated according to said switching sensing signal and said pulse width is set to a default value by said reset signal, and said gated oscillating signal has an active period and a silent period determined by said pulse signal; and a non-overlapping driver, used to generate a high side driving signal and a low side driving signal according to said gated oscillating signal, wherein said high side driving signal and said low side driving signal are active only during said active period of said gated oscillating signal.