초록 ▼

This invention relates to a speed control circuit of a d.c. motor having a frequency generator. To the conventional method in which a rotation detection signal is delayed by a monostable multivibrator circuit and this delayed signal and the rotation detection signal are gated to obtain a speed error

This invention relates to a speed control circuit of a d.c. motor having a frequency generator. To the conventional method in which a rotation detection signal is delayed by a monostable multivibrator circuit and this delayed signal and the rotation detection signal are gated to obtain a speed error signal, a new time-voltage converter circuit is added, whereby even if the detected frequency of the generator is low, a stable speed control is possible. Because of no error synchronization, the present speed control circuit is suited to an apparatus which requires speed switching, and also to semiconductor integration.

대표청구항 ▼

A speed control circuit for a rotating body comprising: means for producing a first signal in response to the rotation of said rotating body, a monostable multivibrator circuit adapted to be triggered by a front edge of said first signal to produce an output signal having a prescribed metastable per

A speed control circuit for a rotating body comprising: means for producing a first signal in response to the rotation of said rotating body, a monostable multivibrator circuit adapted to be triggered by a front edge of said first signal to produce an output signal having a prescribed metastable period, means for producing a second signal in response to the output signal of said monostable multivibrator circuit, means for producing a third signal in response to a logical AND of an inverted signal of said first signal and said second signal, a flip-flop circuit set in response to the front edge of said second signal and reset by a signal related to the rear edge of said first signal, means for producing a fourth signal in response to the output signal of said flip-flop circuit, a time-voltage converter circuit reset by said fourth signal and driven by said third signal, means for producing a fifth signal in response to the output signal of said time-voltage converter, means for producing a sixth pulse signal appearing in a period other than the metastable period of said second signal and sampling said fifth signal, and a sample-hold circuit which holds the sampled fifth signal to produce a seventh signal thereby controlling the speed of said rotating body.