SEMICONDUCTOR DEVICE, IGNITION ANGLE CONVERTING CIRCUIT, POWER SUPPLY DEVICE, LIGHTING DEVICE, AND SIGNAL CONVERTING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device having a small size and a long life, an ignition angle converting circuit, a power supply device, and a lighting device.

SOLUTION: A semiconductor device 40 converts voltage obtained by phase-controlling alternating current voltage with a predetermined ignition angle, into a control signal corresponding to the ignition angle. The semiconductor device 40 comprises a pulse signal converting circuit 1 converting the phase-controlled voltage into a first pulse signal c having pulse length corresponding to the ignition angle; a pulse composite circuit 2 composing the first pulse signal c and a second pulse signal d having frequency higher than that of the first pulse signal c to output a third pulse signal e; and a signal converting circuit 3 counting the number of the pulse of the third pulse signal e during the pulse length of the first pulse signal c, and outputting the control signal corresponding to the counted number of the pulse of the third pulse signal 2.

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