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US 4,902,949 AGranted
Motor servo circuit
AssigneeFuji Photo Film Co., Ltd.
InventorMasafumi Hirata
Life of this patent
Estimating the term…
Abstract
A resistor is provided in parallel with the capacitor of a phase compensating circuit in order that a rapid transition may be made to a steady velocity state when a motor is started, a target velocity (reference velocity) is changed, or a large fluctuation in load occurs. When the steady velocity state does not prevail, the capacitor is isolated from the circuit and the resistor is connected into the circuit in its place.
Claims5
A motor servo circuit comprising:
- a rotational velocity sensor for sensing the rotational velocity of a motor;
- a velocity error sensing circuit for sensing a rotational velocity error by comparing the sensed rotational velocity with a prescribed reference velocity;
- a phase compensating circuit, which includes a capacitor, for controlling a motor driver circuit based on the velocity error signal inputted thereto;
- steady velocity sensing means for sensing a steady velocity state in which the sensed rotational velocity is in the vicinity of the reference velocity;
- a resistance circuit connected in parallel with said capacitor;
- and
- changeover means for selectively connecting one of said capacitor and said resistance circuit into said phase compensation circuit in such a manner that said capacitor is connected to said phase compensating circuit only when a steady velocity state is sensed by said steady velocity sensing means, and said resistance circuit is connected to said phase compensating circuit at all other times.
4 more elements
A motor servo circuit comprising:
- a rotational velocity sensor for sensing the rotational velocity of a motor;
- a velocity error sensing circuit for sensing a rotational velocity error by comparing the sensed rotational velocity with a prescribed reference velocity;
- a phase compensating circuit which includes a capacitor, for controlling a motor driver circuit based on the velocity error signal inputted thereto;
- steady velocity sensing means for sensing a steady velocity state in which the sensed rotational velocity is in the vicinity of the reference velocity;
- a resistance circuit connected in parallel with said capacitor;
- changeover means for changing over between said capacitor and said resistance circuit in such a manner that said capacitor is connected to said phase compensating circuit when a steady velocity state is sensed by said steady velocity sensing means, and said resistance circuit is connected to said phase compensating circuit at all other times;
- a constant bias circuit for outputting a bias signal representing a constant phase error inclusive of a zero phase error;
- and
- second changeover means for changing over between said rotational phase error sensing means and said constant bias circuit in such a manner that a rotational phase error signal outputted by said rotational phase error sensing means is connected to said arithmetic means when a steady velocity state is sensed by said steady velocity sensing means, and the bias signal from said constant bias circuit is connected to said arithmetic means at all other times.
6 more elements
Dependencies are inferred from the claim text.