Panasonic Corporation

Panasonic Electric Works Co., Ltd.

Naoki Komatu

Jun Kumagai

Takeshi Kamoi

Daisuke Yamahara

Takeshi Goriki

Nobutoshi Matsuzaki

Satoru Nagata

Nobuo Ukita

Akira Yufuku

Hiroyasu Eriguchi

Kazuhiko Harada

A discharge lamp ballast and method of operation are provided for generating a DC component in an output voltage during a lamp starting operation having a predetermined duration. The ballast includes an inverter having four switches arranged in a full-bridge configuration, a resonant circuit having a resonant frequency, and a control circuit. The method includes a step of sweeping an inverter operating frequency within a predetermined frequency range including the resonant frequency, wherein a high voltage is generated for igniting the lamp. The method further includes periodically and alternately repeating a first state of turning on a first set of diagonally positioned switching elements and turning off a second set of diagonally positioned switching elements, and a second state of turning on only one of the second set of switching elements and turning off the remaining three switching elements, respectively.

Electronic ballast and method for providing a DC voltage component during lamp startup

A high-voltage discharge lamp lighting device provides a starting pulse voltage sufficient to turn on a high-voltage discharge lamp having terminal wire connections of variable length. A power conversion circuit is coupled to a commercial AC power source input and rectifies the AC input into a predetermined DC voltage output. A charging capacitor is coupled to the power conversion circuit. A full bridge circuit is coupled to the power conversion circuit and the charging capacitor and provides a rectangular wave AC output signal to a transformer primary winding circuit of at least a capacitor, a single switching element and a primary winding of a transformer. A low pulse voltage is induced in the primary winding and a transformer secondary winding is connected on one end to the high-voltage discharge lamp, wherein the low pulse voltage is stepped up to a high pulse voltage and applied to the high-voltage discharge lamp. A reference voltage is generated in a reference transformer winding representative of the high pulse voltage. A starting pulse equivalent value detection circuit is connected to the reference winding and detects a value associated with the reference voltage. A control circuit receives said value from said detection circuit, and variably controls at least one of a frequency of the single switching element or an ON impedance of the single switching element in association with said value, wherein said frequency or ON impedance is further associated with a starting pulse voltage sufficient to start the high-voltage discharge lamp.

High voltage discharge lamp lighting device

Growing community of inventors

Kobe, Japan

Naoki Komatu