JPS62239892A - Motor drive assembly - Google Patents

Abstract

PURPOSE:To permit the tape speed during high speed playback to vary over a wide range, by changing over the source voltage of a motor drive circuit and by adjusting it at the same time. CONSTITUTION:Usually, in recording and playing back the speed, a supply voltage 6a is supplied to a drive circuit 2 through a source voltage change-over circuit 4 from a power circuit 3. The control signal 7a is sent out from a control circuit 5 to the motor drive circuit 2 so that a capstan motor 1 has a rotational speed of N1. Then, during high speed playback, when the capstan motor 1 has a rotational speed of N2 (>N1), a supply voltage 6c is impressed through a power source change-over circuit 4 and a source voltage regulation circuit 9 from a power source circuit 3. At this moment, a control signal 7c is sent out from a control circuit 5 to the motor drive circuit 2 so that the capstan motor 1 may have a rotational speed N3 (>N2) higher enough than N2 and the source voltage 6c is adjusted by the source voltage regulation circuit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a capstan motor drive device during high-speed playback of a VTR.

[Conventional technology]

An example of a conventional VTR Capnutan motor drive device is shown in FIG. (1) is the capstan motor 1 for running the tape (2) is the motor drive circuit that drives the capstan motor (1), (3) is the motor drive circuit (2)
(4) is a power supply voltage switching circuit for increasing or decreasing the power supply voltage of motor drive circuit (2) as required; (5) is a power supply circuit for rotating the capstan motor (1). This is a control circuit for controlling the number.

In general, in addition to normal recording and playback, a VTR is capable of high-speed playback in which the tape speed, ie, the number of revolutions of the capstan motor, is several times to several tens of times faster than normal recording and playback.

During normal speed recording and playback, a predetermined power supply voltage V,
(6a) is supplied to the motor drive circuit (2). Then, a control signal (7a) is sent from the control circuit (5) to the motor drive circuit (2) so that the capstan motor (1) reaches a predetermined rotation speed N1. At this time, the motor drive circuit (
From 2) to 1 capstan motor (1), apply voltage v such that the rotation speed of capstan motor (1) becomes N1.
N+(8a) is added. Assuming that the voltage loss in the motor drive circuit (2) is ■L, these circuits satisfy v1≧vN, +
■It is set to be L.

During high-speed playback, the rotation speed of the capstan motor (1) is set to N.
t (> Nt), the control signal (7b) makes the rotation speed of the capstan motor (1) N2.
is supplied from the control circuit (5) to the motor drive circuit (2), and from the motor drive circuit (2) to the capstan motor (1).
An applied voltage VN2 (8b) is applied to the capstan motor (1) such that the number of rotations of the capstan motor (1) becomes Nt. However, at this time, if Vt<VNt + VL, the voltage from the motor drive circuit (2) to the capstan motor (1) is at most v1.
-V is not applied, and the number of revolutions of the capstan motor is N! Therefore, a method is generally adopted in which the source voltage switching circuit (4) switches the power supply voltage Vz (≧VNz + Vt, ) to be supplied to the motor drive circuit (2).

[Problem that the invention seeks to solve]

Conventional motor drive devices are configured as described above, so when trying to obtain various rotational speeds from very high speeds to not so high speeds during high-speed playback on a VTR etc., the motor drive circuit ( 2) It is necessary to set the power supply voltage v2 high and set the motor applied voltage vN2 to various values within the range of VNt + Vt, < Vt. ■2-vN! may become extremely large. The power consumed by the motor drive circuit (2) is: ■2-VNt
Since the power consumption increases in proportion to , the power consumption of the motor drive circuit (2) may become extremely large. However, since the motor drive circuit (2) is generally installed close to the capstan motor (1) in VTRs, etc., it is often difficult to attach a large heat sink, and the circuit itself is highly integrated. Since it is not possible to consume a large amount of power, the above configuration has a problem in that the variable range of the rotation speed is significantly limited.

The present invention has been made in order to solve the above-mentioned problems, and provides a motor drive device that enables faster high-speed playback than before in VTRs and the like, and that can vary the tape speed over a wide range during high-speed playback. The purpose is to

[Means for solving problems]

A motor drive device according to the present invention is capable of switching and adjusting the power supply voltage of a motor drive circuit at the same time.

[Effect]

In this invention, the power supply voltage switching circuit switches the power supply voltage of the motor drive circuit, and at the same time, the power supply voltage adjustment circuit adjusts the power supply voltage and adjusts the motor rotation speed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, (1) is a capstan motor, (2) is a motor drive circuit that drives the capstan motor (1),
(3) is a power supply circuit for supplying the power supply voltage of the motor drive circuit (2); (4) is a power supply voltage switching circuit for increasing or decreasing the power supply voltage of the motor drive circuit (2) as required; (5) ) is a control circuit for controlling the rotation speed of the capstan motor (1), and (9) is a power supply for adjusting the power supply voltage of the motor drive circuit (2) when rotating the capstan motor (1) at high speed. This is a voltage adjustment circuit.

Next, the operation will be explained. During normal speed recording/reproduction, a predetermined N and source voltage V'+(6a) are supplied from the power supply circuit (3) to the motor drive circuit (2) through the power supply voltage switching circuit (4). Then, the control circuit (5) controls the capstan motor (1) to a predetermined rotation speed N1.
), a control signal (7a) is sent to the motor drive circuit (2). At this time, an applied voltage VN, (8a) is applied from the motor drive circuit (2) to the capstan motor (1) so that the number of rotations of the capstan motor (1) becomes N1. If the voltage loss in the motor drive circuit (2) is VL, these circuits are set so that v1≧vNt + VL.

Next, when the rotation speed of the capstan motor (1) is set to Nt (>N+) during high-speed playback, from the power supply circuit (3),
A power supply voltage va (6c) is applied through a power supply switching circuit (4) and a power supply voltage adjustment circuit (9). At this time, the capstan motor (1) rotates at a sufficiently high rotation speed Ns.
(>>Nt) is sent from the control circuit (5) to the motor drive circuit (21)!
R1Vs t Vs = vNz ” Vt, (!:
If the power supply voltage adjustment circuit (9) is adjusted so that (
However, here -7 is the rotation t of the capstan motor (1)
It is the applied voltage applied from the motor drive circuit (2) to the capstan motor (1) such that Nt is 1V.
L is the voltage loss in the 1-motor drive circuit (2). )
, the capstan motor (1) rotates at a rotation speed N2. As a matter of course, the rotation speed of the capstan motor (1) can be adjusted by adjusting the voltage value of the power supply voltage v3 using the power supply voltage adjustment circuit (9).

The power supply voltage adjustment circuit (9) may have a simple configuration using a variable resistor or the like that allows the user to freely change the rotation speed, or it may be a circuit that detects the rotation speed of the motor. A circuit that controls the rotation speed by feedback control may also be used. Further, in the above embodiment, V'I'
Although R has been described, it may be an audio tape recorder or a device such as a winder.

〔Effect of the invention〕

As described above, according to the present invention, the configuration is such that the difference between the power supply voltage of the motor drive circuit and the voltage applied to the motor is minimized, so that it is possible to operate at various speeds without increasing the power consumption of the motor drive circuit. High-speed playback can be achieved with an inexpensive configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a block diagram showing a conventional device. (Old...Motor, (2)...Motor drive circuit, (3)
...Power supply circuit, (4)...Power supply voltage switching circuit, (9
)...Power supply voltage adjustment circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] A motor drive circuit that drives the motor, a power supply circuit that supplies power supply voltage to the motor drive circuit, a power supply voltage switching circuit that switches the power supply voltage of the motor drive circuit, and a power supply voltage that adjusts the power supply voltage of the motor drive circuit. A motor drive device comprising an adjustment circuit, the rotation speed of the motor being adjusted by switching the power supply voltage of the motor drive circuit and adjusting the power supply voltage of the motor drive circuit.