Electronic ballast with constant power output controller for 250 W MHD lamp

In this paper, an electronic ballast was developed to control 250 W metal halide lamp. To avoid acoustic resonance phenomenon, the authors calculated the acoustic resonance band and determined the driving frequency to be from 70 kHz to 100 kHz. Due to the switching loss of MOSFET, many problems are caused in the inverter circuit during lighting of the lamp, so the authors have reduced the loss by connecting the capacitor to reduce inrush current. In this paper, the main research area is to find methods to operate the lamp on regulated constant output. After detecting the current I and voltage V of the lamp, the authors changed the driving frequency by changing the DC voltage level.