| 摘要 |
PURPOSE:To sample-hold a stable counterelectromotive force by increasing the pulse width of a sample-holding control signal for sampling the force wider than the pulse width of a transistor drive signal. CONSTITUTION:Transistors 10-1-10-4 are controlled by a transistor drive signal TD fed from a pulse width modulation signal generator 2. A sample-holding circuit 4 sample-holds the output of a differential amplifier 11 connected in parallel with a DC motor M by a sample-holding control signal synchronized with the signal TD from a sample-holding control signal generator 12, and outputs as a speed signal. The pulse width of the sample-holding control signal is wider than that of the drive signal TD to sample a stable counterelectromotive force. |
