| 摘要 |
<p>PURPOSE: To reliably stabilize the loop of a discharge lamp by providing it with a plurality of transformers and a serial resistor circuit connected in a specific method and controlling the power of the lamp through the addition of generated voltage and current signals. CONSTITUTION: An inverter 2 supplies a sinusoidal AC signal from a secondary coil 5 of an output transformer 4 to a discharge lamp 1. During the operation of the lamp 1, a voltage drop proportional to a lamp current is caused in a current-sensitive resistor 11, and a current-sensitive transformer 13 induces a voltage proportional to the lamp current in a secondary coil 14. Transformers 8 and 4 are connected in series, and thus a voltage across secondary coils 9 and 16 or a voltage to ground of a terminal 18 becomes proportional to a lamp voltage. A voltage appearing across all the serially connected coils 9, 14 and 16 become proportional-to a current of the lamp 1. As a result, a voltage to ground of a terminal 15 obtained by adding the voltage to ground of the terminal 18 and the voltage of the coil 14 becomes substantially proportional to the power of the lamp. A correction signal obtained through comparison with a reference value controls the output of the inverter so as to change the power of the lamp and thus reliably stabilize the loop of the lamp.</p> |
