Patent ID: 6316882
Filing Date: 2001-11-13
Classification: H05B,Y02B,Y10S

Abstract:
A current amplifier for use in an electronic ballast, the current amplifier comprising:a current source;a differential amplifier coupled to the current source, the differential amplifier including first and second resistors and first and second transistors, wherein an emitter terminal of the first transistor is coupled to the first resistor and an emitter terminal of the second transistor is coupled to the second resistor;a selection circuit including third and fourth transistors, wherein an emitter terminal of the third transistor is coupled to an emitter terminal of the fourth transistor and the emitter terminals of the third and fourth transistors are coupled to a base terminal of the second transistor;a first current mirror;a second current mirror coupled to the first current mirror and to a collector terminal of the first transistor; anda third current mirror coupled to the first current mirror and to a collector terminal of the second transistor.