Lighting method of the at least one fluorescent lamp and electronic ballast for the

摘要

PROBLEM TO BE SOLVED: To surely adjust load current after a lamp is aged and control the lamp having dangerous ignition behavior by setting a prescribed level value of a DC signal overlapped on a signal of a load current supplied to a monitor circuit in ignition and generated in a control and adjust circuit in accordance with the type of the lamp and circuit, and matching the overlapped signal to a fixed reference level independent of the selection of the lamp.;SOLUTION: A DC signal having a level capable of setting in accordance with a lamp circuit used is overlapped only during ignition on a load current signal monitored with a control and adjust circuit IC connected to a load circuit 4 having at least one fluorescent lamp FL through a half bridge circuit, power transistors V2, V3. A level of this bias voltage signal generating from a second inner power source is simply drawn from current flowing through a first set resistor RTU for determining a blanking interval of the power transistors V2, V3 by resistance value, attached to a current control transmitter CCO. Therefore, the tolerance range of an electronic ballast relating to monitor of load current is widened.;COPYRIGHT: (C)2001,JPO