초록 ▼

A feedback control system of ballast which has function to detect the number of lamp and is applied to an integrated circuit to control the ballast for a fluorescent lamp etc, and provides the ballast with the feedback control system which can detect the number of lamp, control ballast continuously

A feedback control system of ballast which has function to detect the number of lamp and is applied to an integrated circuit to control the ballast for a fluorescent lamp etc, and provides the ballast with the feedback control system which can detect the number of lamp, control ballast continuously by means of the n-lamp detector and soft start controller which produce the compensated current from the feedback current and direct link voltage. Therefore, the feedback control system can control the ballast accurately according to the load change such as the change of input voltage, number of lamp.

대표청구항 ▼

[ What is claimed is:] [1.] A switching type ballast feedback control system, comprising:a ballast which generates a feedback current;a detector which detects a number of lamps connected to the ballast;a reference voltage generator which generates a reference voltage corresponding to the number of l

[ What is claimed is:] [1.] A switching type ballast feedback control system, comprising:a ballast which generates a feedback current;a detector which detects a number of lamps connected to the ballast;a reference voltage generator which generates a reference voltage corresponding to the number of lamps detected by the detector;a soft start controller unit which produces a first output current corresponding to the number of lamps detected by the detector in an initial preheat period, an instantaneous discharge period and a continuous discharge period;a first feedback unit which multiplies said feedback current of the ballast with a direct link current applied to the ballast to obtain a multiplied current that is added to the first output current of the soft start controller unit to form a second output current;a second feedback unit which converts the second output current into a voltage, produces an error voltage as a difference between the converted voltage and the reference voltage generated by the reference voltage generator and converts the error voltage into a third output current;a main control unit which adds the third output current of the second feedback unit to a feedforward current and determines a control frequency of a driving signal of the ballast from this added current.