Discharge-lamp lighting device

摘要

A lighting device has a direct-current power generation circuit, a rectangular-wave generation circuit, a pulse generating circuit, lamp-voltage detection means, and pulse-generation command means. The direct-current power generation circuit generates direct-current power from external power. The rectangular-wave generation circuit converts the direct-current power to rectangular-wave alternating-current power. The pulse generating circuit superposes high-voltage pulses on the rectangular-wave power output from the rectangular-wave generation circuit and starts a discharge lamp. The lamp-voltage detection means detects, in digital form, a lamp voltage supplied to the discharge lamp. The pulse-generation command means issues a pulse generation command to the pulse generating circuit when the value detected by the lamp-voltage detection means reaches a predetermined no-load-voltage determination level.

主权项

1. A discharge-lamp lighting device comprising:
a direct-current power generation circuit that generates direct-current power from external power, a rectangular-wave generation circuit that converts the direct-current power to rectangular-wave alternating-current power, a pulse generating circuit that superposes high-voltage pulses on the rectangular-wave power output from the rectangular-wave generation circuit and starts a discharge lamp, lamp-voltage detection means for detecting, in digital form, a lamp voltage supplied to the discharge lamp, and pulse-generation command means for issuing a pulse generation command to the pulse generating circuit when the value detected by the lamp-voltage detection means reaches a predetermined no-load-voltage determination level, input-voltage detection means for detecting the input voltage of the direct-current power generation circuit in digital form, and input-voltage judging means for giving the detection signal of the input voltage to the pulse-generation command means according to the value detected by the input-voltage detection means, and wherein the pulse-generation command means issue the pulse generation command when the detected value of the lamp voltage reaches the no-load-voltage determination level and when the detection signal of the input voltage is received.