| 摘要 |
PURPOSE:To form a more accurate PWM waveform applied to a motor by providing a logic circuit for forming an ON delay waveform of a power transistor. CONSTITUTION:A timer 13 which is composed of a delay time settable program counter inputs a PWM waveform ROM access signal 6 and outputs a signal pulse delayed by a time T from the signal to FFs 14, 15, 16. A PWM waveform ROM 7 inputs a PWM waveform ROM access signal 6, outputs U, V and W signals by the signal, and outputs them through an FF17 to the FFs 14, 15, 16. The FFs 14, 15, 16 combine the waveforms for providing an ON delay of a power transistor from the signal from the FF17 and the delay signal from a timer 13, and output them. Thus, since the phase voltages become uniform and the waveform approaches a sinusoidal wave, the vibration and the noise of a motor are improved. |
