Patent ID: 6040661
Filing Date: 2000-03-21
Classification: H05B,Y10S

Abstract:
A universal lamp system comprising:(a) a lamp having a predetermined set of lamp operating characteristics, said operating characteristics including a lamp running voltage and a filament voltage, said lamp running voltage having a value between a first value and a second value and said lamp filament voltage having a value between a third value and a fourth value;(b) a universal ballast having:(i) a first power circuit for outputting a high frequency AC signal;(ii) a coupling circuit coupled to the power circuit for applying the AC signal to the lamp to provide said lamp running voltage and said filament voltage at said lamp; and(iii) a control circuit adapted to vary the duty cycle of the AC signal in a range of between about a 50/50 ratio and about a 2/98 ratio and the frequency of the AC signal in a range of between about 20 and about at least 47 kilohertz but not greater than about 55 kilohertz and therefore to vary said lamp running voltage between said first and second values and said filament voltage between said third and fourth values, said first and second values having a difference between them of about 77 percent and said third and fourth values having a difference between them of about 58 percent.