Effective Implementation of an HID Lamp Ballast using a Single Chip Microcontroller

This paper presents an effective implementation of high intensity discharge (HID) lamp ballast using a low-cost 8 bit single chip microcontroller, PIC16C73, to optimize total system size and to minimize cost through minimization of total component number. The proposed ballast generates high open-circuit voltage to ignite the lamp and is controlled to supply effectively the power required to shorten warm-up period after the breakdown. The DC-DC converter of the ballast utilizes the flyback converter topology that can minimize component number. Also, to more minimize the ballast size, the transformer size must be minimized. For this, PWM (pulse width modulation) pulses are generated with high frequency using the PWM module of the microcontroller. An analysis about this is explained, briefly. If the operation of the lamp and ballast arrives at steady-state, then the ballast must control the lamp with AC current. For this, the microcontroller utilizes the other PWM module of it. And the part related to the igniter is explained, briefly. It is shown through experimental results that the controller of the proposed ballast has good performance for the HID lamp operation