Patent ID: 7982413
Filing Date: 2011-07-19
Classification: H05B,Y10S

Abstract:
1. 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 the minimum operation voltage of said electronic ballast; a dimming voltage generator, used to generate a dimming voltage according to a count of said switching sensing signal and said dimming voltage generator is reset by said reset signal when said power line is turned off for a period exceeds a predetermined time; and a phase-controlled non-overlapping driver, used to generate a high side driving signal and a low side driving signal for delivering a lamp current according to said dimming voltage, wherein said dimming voltage is used to generate a phase, and said phase is used to generate said lamp current.