Patent ID: 7112930

Claim:
A high voltage detecting device, comprising: a discharge lamp having an excitation voltage and a lighting voltage applied thereon; a boost circuit coupled to said discharge lamp for providing an operation voltage to said discharge lamp wherein said operation is voltage is lower than said excitation voltage but higher than said lighting voltage; and a switch circuit coupled to said boost circuit for providing a periodical high-low signal level to control said boost circuit, wherein said boost circuit is turned off when said periodical high-low signal level is relatively high, while said boost circuit is turned on when said periodical high-low signal level is relatively low, and wherein when said booster circuit is turned off via said relatively high periodical high-low signal level, said operation voltage is lower than said lighting voltage, and when said boost circuit is turned on via said relatively low periodical high-low signal level, said operation voltage is higher than said excitation voltage, and thereby said discharge lamp flickers.