JPH0274187A - Rotation controller of motor - Google Patents

Abstract

PURPOSE:To keep down the power consumption of a video signal recorder such as an electronic still camera by providing an oscillation circuit to generate a speed reference signal besides an oscillation circuit to generate a phase reference signal and a synchronous signal. CONSTITUTION:A speed detection circuit 11 detects that the rotating speed of a motor 1 becomes a specified speed from a speed control signal (d) of a speed detection signal (1). Besides an oscillation circuit 3 for controlling the speed of the motor 1, an oscillation circuit 12 is provided which is operated from the power source in another system different from the oscillation circuit 3 and from which a reference clock signal (m) is outputted to a phase reference generation circuit 7 and a synchronous signal generation circuit 8. With a signal (1) the power is supplied to a video signal processing circuit 13 composed of the circuit 12, the phase reference generation circuit 7 and the synchronous signal generation circuit 8.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a motor rotation control device.

In conventional video signal recording devices, such as electronic still cameras, a magnetic sheet is rotated by a motor, and a PG (phase pulse gene) indicating the rotational phase of the magnetic sheet is generated.
(rator) The phase relationship between the detection signal from the yoke and the vertical synchronization signal of the video signal must be maintained at a predetermined phase for recording. In addition, with electronic still cameras, it is desirable to start rotating the magnetic sheet immediately before taking a picture and stop it as soon as recording is completed to reduce power consumption.Furthermore, after pressing the shutter button, the motor locks in the phase and starts recording. There is a desire to shorten the time it takes to complete the process as much as possible. Therefore, P indicates the rotational position of the magnetic sheet.
The synchronization signal generation circuit is reset so that the phase relationship of the vertical synchronization signal of the G multiplied signal video signal becomes a predetermined phase, and the PG
A method has been proposed in which the phase of the double signal vertical synchronization signal is forced into a predetermined relationship.

Below is a conventional motor rotation control device using the above method.
This will be explained based on the block diagram in FIG.

A motor rotation control device generally includes a speed control means that maintains a constant rotational speed, and a phase control means that adjusts the rotational phase of the motor rotor with a phase reference signal.

First, the speed control means will be explained. A rotational speed signal a which is an output signal of a frequency generator (hereinafter abbreviated as FG) 2 which generates a signal proportional to the rotational speed of a motor 1 that rotationally drives a magnetic sheet, and a reference clock signal S generated by an oscillation circuit 3. The frequency of the speed reference signal C of the motor 1, which is generated by frequency division in the speed reference signal generation circuit 4, is compared with the speed comparison circuit 5, which is speed control means, and the frequency of the rotational speed signal a and the speed reference signal C is compared. A speed control signal d corresponding to the difference in speed is output. When the frequency of the rotational speed signal a of FG2 is higher than the frequency of the speed reference signal C, a speed control signal d is outputted to lower the rotational speed of the motor 1, and when it is lower, the speed control signal d is outputted to increase the rotational speed of the motor 1. By outputting the control signal d, the rotational speed of the motor 1 is controlled to be kept constant.

Next, the phase control means will be explained. The reference clock signal S generated by the oscillation circuit 3 is input to a phase reference generation circuit 7, output as a phase reference signal e, and input to a phase comparison circuit 6 which is a phase control means. It compares the phases of the rotational speed signal a of FG2 and the phase reference signal e, outputs a phase control signal f corresponding to the phase difference I, and controls the rotation of the motor 1 so that the phases have a predetermined relationship. . Here, if FG2 generates two pulses for each rotation of motor 1 and motor 1 rotates at n (rps), the frequency/r (Hz) of phase reference signal e is fr
=Zxn must be satisfied.

The reference clock signal generated by the oscillation circuit 3 is also input to a synchronous signal generation circuit 8, and a vertical sync signal g and various sync signals for video signal processing are output. The phase pulse generator (hereinafter abbreviated as PG) 9 outputs a rotational phase signal j consisting of one pulse per rotation, representing the rotational phase of the rotor of the motor 1, and the rotational phase signal j of this PG9 A phase detection circuit 10 compares the phases of and the vertical synchronization signal g, and if the phases do not have a predetermined relationship, that is, 7H±Δt (H is the horizontal synchronization signal period, and Δt is a predetermined detection width), A reset signal k is output to the synchronization signal generation circuit 8 to apply a reset, forcing the synchronization signal gth to have a predetermined phase relationship with the rotational phase signal j of the PG 9.

Problems to be Solved by the Invention However, in the above conventional configuration, the speed reference signal C and the phase reference signal e are formed using the reference clock signal S generated by the same oscillation circuit 3, and the Since the synchronization signals g, h and the phase reference signal e must be synchronized, the synchronization signal generation circuit 8 for the video signal also uses the reference clock signal generated by the same oscillation circuit 3. .

At the same time as the motor 1 is started, it is also applied to the phase reference generation circuit 7 and the synchronization signal generation circuit 8 that constitute the video signal processing circuit! This has hindered efforts to reduce power consumption.

The present invention solves the above problem by providing an oscillation circuit for generating a speed reference signal separately from an oscillation circuit for generating a phase reference signal and a synchronization signal, so that the rotational speed of the motor is at a predetermined speed. To provide a motor rotation control device capable of suppressing power consumption by turning on a video signal processing circuit and starting oscillation of an oscillation circuit for generating a phase reference signal after detecting that The purpose is to

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a first clock generating means for generating a first reference clock signal, and a first clock generating means for generating a motor from the first reference clock signal of the first clock generating means. speed reference signal generation means for forming a speed reference signal of the motor; speed control means for controlling the motor so that a rotational speed signal of the motor and a speed reference signal of the speed reference signal generation means have a predetermined relationship; speed detecting means for detecting that the rotational speed of has reached a predetermined speed; and a speed detecting means that operates on a power source separate from the first clock generating means based on the speed detection signal of the speed detecting means, and generates a second reference clock signal. and a second clock generating means for generating a second clock of the second clock generating means based on the speed detection signal of the speed detecting means.
a phase reference signal generating means for forming a phase reference signal for the motor synchronized with a video signal from a reference clock signal of the motor; and phase control means for controlling the motor.

Operation With the above configuration, the second clock generation means and phase reference generation means for controlling the phase of the motor, which are provided separately from the first clock generation means for controlling the speed of the motor, can be connected to the rotational speed of the motor. It is operated by a speed detection signal from a speed detection means that detects that the speed has reached a predetermined speed.

Therefore, the second clock generation means and the phase reference signal generation means are not operated at the same time as the recording of one motor, and the power consumption can be reduced.O Embodiment Hereinafter, one embodiment of the present invention will be explained based on the drawings. I will explain.

FIG. 1 is a block diagram of a motor rotation control device showing one embodiment of the present invention. Note that the same components as those in FIG. 2 of the conventional example are designated by the same reference numerals, and description thereof will be omitted.

In FIG. 1, reference numeral 11 denotes a speed detection circuit for detecting that the rotational speed of the motor I has reached a predetermined speed based on the speed control signal d of the speed comparison circuit 5; The oscillation circuit 3 is provided separately from the oscillation circuit 3, and operates with a power source (not shown) from a separate system, and the phase reference generation circuit 7
and a second reference clock signal m to the synchronization signal generation circuit 8.
The speed detection signal l of the speed detection circuit U supplies power to the oscillation circuit pressure and phase reference generation circuit 7 and the synchronization signal generation circuit 8 that constitute the video signal processing circuit port.

Next, the operation of the above configuration will be explained.

First, the operation of the speed control means is similar to that of the conventional device shown in FIG. The speed comparison circuit 5 compares the frequency of the speed reference signal C generated by splitting the reference clock signal C of the reference clock signal C in the speed reference signal generation circuit 4, and drives the motor 1 in accordance with this frequency difference. Keep the rotation speed of 1 constant. In the electronic still camera of this embodiment, when release [1] (release SW pressed halfway) is pressed, motor 1 is activated, and when release [2] is further pressed, exposure and recording are performed. First, when the release [1] is pressed, power is supplied to the speed control means and the motor 1, the motor 1 is started, and the speed control means controls the rotational speed of the motor 1 to a predetermined speed. And speed detection circuit■
1, it is detected that the rotational speed of the motor 1 has reached a predetermined speed, and if the release button [2] is pressed, power is supplied to the video signal processing circuit port, and the second oscillation circuit pressure oscillates. The second reference clock signal m of the second oscillation circuit pressure is frequency-divided in the phase reference signal generation circuit 7,
A phase reference signal e is output.

Then, as in the conventional case, the phase comparison circuit 6 compares the phases of the rotational speed signal a of the FG2 and the phase reference signal e.
A phase control signal f corresponding to the phase difference is output, and the rotation of the motor 1 is controlled so that the phases have a predetermined relationship. Further, the second reference clock signal m of the second oscillation circuit pressure is input to the synchronization signal generation circuit 8, and the vertical synchronization signal g and each synchronization signal for video signal processing are output. Then, as in the conventional case, the phase detection circuit 10 compares the rotational phase signal j of the PG 9 and the phase of the vertical synchronization signal g, and if the phases do not have a predetermined relationship, a reset signal k is sent to the synchronization signal generation circuit 8. is output to apply a reset, forcing the synchronization signal gth to have a predetermined phase relationship with the rotational phase signal j of the PG 21.

In this way, the oscillation circuit that outputs the second reference clock signal m for the phase reference signal is provided separately from the oscillation circuit 3 that outputs the reference clock signal m for speed control, and after starting the motor 1, After the speed detection circuit 11 detects that the rotational speed of has reached a predetermined speed, power is supplied to the video signal processing circuit 13, and the oscillation circuit P that outputs the reference clock signal m for the phase reference signal is operated. As a result, the video signal processing circuit 1 simultaneously starts the motor 1.
3, it is no longer necessary to supply power to the third terminal, and power consumption can be reduced.

Effects of the Invention As described above, according to the present invention, when the speed detection means detects that the rotational speed of the motor has reached a predetermined speed, the first clock generation means for controlling the speed of the motor is activated. The video signal processing circuit is operated after the motor is started until the rotational speed reaches a predetermined speed by operating a second clock generation means for controlling the phase of the motor and a phase reference signal generation means, which are provided separately. There is no need to supply power to the second clock generation means and phase reference signal generation means, which constitute the second clock generation means and phase reference signal generation means, and an excellent effect of reducing power consumption can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a motor control device showing an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional motor control device. DESCRIPTION OF SYMBOLS 1... Motor, 3... (first) oscillation circuit (clock generation means), 4... Speed reference signal generation circuit, 5...
・Speed comparison circuit (speed control means), 6... Phase comparison circuit (phase control means), 7... Phase reference signal generation circuit,
11... Speed detection circuit, hill... (second) oscillation circuit (clock generation means), a... (motor) rotational speed signal, b... first reference clock signal, C. ...Speed detection signal, e...Phase reference signal, j...Rotation phase signal (of the motor), l...Speed detection signal, m...Second
reference clock signal.

Claims (1)

[Claims] 1. a first clock generating means for generating a first reference clock signal; a speed reference signal generating means for forming a motor speed reference signal from the first reference clock signal of the first clock generating means; a speed control means for controlling the motor so that a rotational speed signal of the motor and a speed reference signal of the speed reference signal generation means have a predetermined relationship; and a speed for detecting that the rotational speed of the motor has reached a predetermined speed. detecting means and a speed detection signal of the speed detecting means, the second clock generating means is operated by a power source separate from the first clock generating means;
a second clock generating means for generating a reference clock signal of the second clock generating means; and a phase reference signal of the motor synchronized with the video signal from the second reference clock signal of the second clock generating means according to the speed detection signal of the speed detecting means. and phase control means for controlling the motor so that the phase reference signal of the phase reference signal generating means and the rotational phase signal of the motor have a predetermined relationship. Device.