| 摘要 |
PURPOSE:To obtain high responsiveness in both current continuous state and current interrupted state by deciding a firing phase angle on the basis of only the result of calculating a current control when a load current is in the current interrupted state. CONSTITUTION:An A/D converter 6 outputs a current momentary value If of a digital signal from the output of a current detector 4 and a current average value If. A delay time circuit 8 outputs an interrupt signal after the prescribed time is elapsed from when a firing pulse generator 7 outputs a firing pulse. When a microcomputer 9 inputs the interrupt signal, it calculates to control the current and the current change rate to decide a firing phase angle alpha. A current interruption detector 11 outputs a current interruption detection signal SD on the basis of the firing pulse and the load current, and when the microcomputer 9 inputs the signal DD, it decides the angle alpha only by the calculation of controlling the current. |
