China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

Electronic ballasts protection circuit when the lamp end of life. It is enclosed in the first comparator, the second comparator and for lamp automatically restart the MOS transistor, said first comparator is the positive terminal of sampling the negative half cycle of the lamp voltage, and its negative terminal as a reference point; said the positive terminal of the second comparator connected to said first comparator's negative terminal, the negative terminal of the sampling of the lamp voltage of the positive half cycle; said two output terminal of the comparator through the SCR is connected to the oscillation drive circuit supply terminal. Lamp at the end of life in the positive and negative half-cycle voltage will drop two comparator will detect the change and trigger the SCR conduction, the oscillator drive circuit to stop vibration, the product has been in protected status until the lamp changing lamp protection start control MOS tube opening, thereby cutting the thyristor conduction maintain current, thyristor cut-off, the lamp changing automatic restart function.