Patent ID: 6169375
Filing Date: 2001-01-02
Classification: H05B,Y10S

Abstract:
A ballast circuit for energizing a lamp, comprising: a resonant circuit including a resonant inductive element coupled to first and second switching elements; a first control circuit coupled to the first switching element for controlling a conduction state of the first switching element; a second control circuit coupled to the second switching element for controlling a conduction state of the second switching element, the second control circuit including a third switching element coupled to the second switching element, the third switching element having a first state which causes the second switching element to transition to non-conductive state and a second state which allows the second switching element to transition to a conductive state; and a third control circuit having a fourth switching element coupled to the third switching element for controlling a conduction state of the third switching element; a bias element coupled to the second and third switching elements for biasing the second and third switching elements between said conductive and non-conductive states; and a delay circuit for biasing the third switching element to the first state a predetermined time interval after the second switching element transitions to a conductive state, said delay circuit having a resistor in parallel with said fourth switching element such that a conduction state of said fourth switching element bypasses said resistor.