| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve a problem that fluctuation of a difference between a sampling frequency and a frequency of a noise component is generated in supply power to a discharge lamp 1 to cause a blink of light of the discharge lamp 1 when the noise component of the frequency slightly different from the sampling frequency of a microcomputer 7 for measuring the voltage from a voltage measurement terminal 1 is superimposed on output voltage of a DC/DC converter 4. SOLUTION: By setting a cutoff frequency of a low-pass filter 6 to not more than a frequency lower than the sampling frequency of the microcomputer 7 by 50 Hz, the noise component is not superimposed on the supply power to the discharge lamp 1.</p> |
