Sansha Electric Manufacturing Company, Limited

Tatsuya Kawabata

Hiroki Morimoto

A power supply circuit () is responsive to an activating signal by supplying a discharge lamp () with an operating voltage on which a high voltage is temporality superposed. An insufficient current detecting circuit () detects abnormality of an output current supplied to the discharge lamp () from the power supply circuit (). A CPU () stops the operation of the power supply circuit () in response to detection of abnormality by the insufficient current detecting circuit (). An output nullification time period timer () nullifies the output of the insufficient current detecting circuit () for a predetermined time period measured from the supplying of the activating signal.

Discharge lamp igniting apparatus

Each of master and slave switching power supply apparatuses () has an IGBT (or) switching-controlled by a PWM pulse signal produced, based on a clock signal, by a switching device driving PWM pulse output section (or), to thereby provide DC power in parallel to a load (). The clock signal produced in the master switching power supply apparatus () is coupled to the slave switching power supply apparatus () through a photocoupler () in the master switching power supply apparatus () and a photocoupler () of the slave switching power supply apparatus (). Also, the clock signal developed at the output of the photocoupler () is coupled through a photocoupler () to the master switching power supply apparatus (). The photocouplers () have the same delay characteristic.

Growing community of inventors

Osaka, Japan

Tatsuya Kawabata