Patent ID: 6710555
Filing Date: 2004-03-23
Classification: H05B,Y02B

Abstract:
A discharge lamp lighting circuit comprising:a driving means to send out a signal for lighting a discharge lamp; a control means to control the driving means; a short-circuit protection means to protect the driving means by sending a signal to the control means when the discharge lamp is shorted; and an open-circuit protection means to protect the driving means by sending a signal to the control means when the discharge lamp is not lighted, the open-circuit protection means being adapted to send out to control means a signal for limiting a current flowing in the driving means to or below a predetermined value when the tube current is equal to or lower than a first value predetermined, and a signal for sequentially increasing a current flowing in the driving means up to a rated current when the tube current is higher than the first value and also is equal to or lower than a second value predetermined, and adapted to stop a driving signal sent from the control means when a tube current flowing in the discharge lamp has a value equal to or lower than the first value after a predetermined time.