Patent ID: 6791279
Filing Date: 2004-09-14
Classification: H05B,Y10S

Abstract:
An electronic ballast for driving a current in at least one fluorescent lamp from a power supply, comprising:a single-switch inverter with an inductance; and a resonant circuit, connected to the output of said inverter and arranged to be connectable to said at least one lamp; wherein when the switch of said inverter is conductive said resonant circuit has a first resonant frequency, and when said switch of said inverter is non-conductive said resonant circuit combines with said inductance of said inverter to form a circuit having a second resonant frequency lower than the first; wherein said inverter is arranged to produce a high frequency alternating current in said at least one lamp at an operating frequency below said first resonant frequency; and wherein the value of said inductance is substantially lower than the maximum value that would permit the ballast to supply its maximum designed power.