JP4140099B2 - Motor equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotation speed control circuit for a capstan motor such as a video tape recorder.
[0002]
[Prior art]
The detection of the rotation speed of a capstan motor such as a video tape recorder is performed in order to detect the tape feed speed and know the tape feed amount. One example will be described with reference to FIG. In the following description, “rotational speed detection” is referred to as “FG (Frequency Generator)”.
[0003]
The capstan motor is composed of a main magnet 14 as a rotor, a magnet 15 for FG, a capstan shaft 16, a motor coil 3 as a stator, an FG signal generator 6, a housing (not shown), a shaft holder, a position detecting Hall element, and the like. Yes.
[0004]
The main magnet 14 has S and N poles alternately arranged in the plane, and when a motor ON signal is input to the input terminal 11, an appropriate motor driving signal S1 according to the state of the position detecting Hall element. Is generated by the motor drive signal generator 2 and supplied to the motor coil 3 disposed opposite to the main magnet 14 to rotate the rotor, and the magnetic tape 18 sandwiched between the capstan shaft 16 and the pinch roller 17. Runs.
[0005]
In addition, when the motor ON signal is not input to the input terminal 11, the motor stops. In this case, naturally, the motor drive signal S1 is unnecessary, so that a power save signal is input to the input terminal 12 as necessary. Then, by controlling the power supply control unit 1 and putting the motor drive signal generation unit 2 in a standby state, power consumption can be saved.
[0006]
Next, an FG for detecting the number of rotations of the motor will be described in order to keep the traveling speed of the magnetic tape 18 constant and know the tape feed amount.
[0007]
The FG magnet 15 is integrally attached around the main magnet 14, and 360 S poles and N poles are alternately magnetized per round. The FG signal generator 6 arranged in close proximity picks up the magnetic flux of the FG magnet 15 and outputs an output voltage corresponding to the direction and magnitude of the magnetic field as an alternating signal of 360 waves per rotation of the rotor, at a frequency proportional to the rotational speed. Signal S2 is obtained.
[0008]
For the FG signal generator 6, for example, a magnetoresistive element suitable for a short wavelength magnetic field is used. In this magnetoresistive element, a resistor whose resistance value changes according to the magnetic flux density is bridge-connected.
[0009]
When the power supply voltage is applied from the input terminal 13 to the magnetoresistive element that is the FG signal generator 6, the output is balanced when there is no magnetic field, but the output is unbalanced due to the application of the magnetic field. Since the output signal level at this time is only about 20 mV between the peaks, it is amplified by the FG amplifier 4 and outputted to the output terminal 10 at the logical value level, to the next stage servo circuit and the microcomputer for calculating the tape feed amount. Send it out.
[0010]
Even when the capstan motor is stopped, the FG output of the output terminal 10 needs to continue to output a logical value in order not to miscalculate the tape feed amount. Therefore, the FG signal generation unit 6 and the FG amplification unit 4 must always be in an active state.
[0011]
Now, video tape recorders, especially video camera recorders, have a long pause time with respect to the actual shooting time. To extend the battery life, not only lower power consumption during actual shooting but also power saving in the paused state. It is necessary to plan.
[0012]
By the way, when the video camera recorder is in a paused state, the tape remains sandwiched between the capstan shaft 16 and the pinch roller 17 so that the tape travel can be started at any time, and the tape travel is stopped by stopping the capstan motor. It has stopped. Therefore, in order to save power, when the capstan motor is stopped, the signal from the FG signal generator 6 does not change, so that each unit for obtaining the FG output can be set in a standby state.
[0013]
[Problems to be solved by the invention]
Accordingly, the present invention is intended to provide a rotation speed control circuit that enables the FG signal generation unit and the FG amplification unit to be in a standby state when the capstan motor is stopped, thereby reducing power consumption. is there.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, a motor device according to the present invention includes a main magnet constituting a rotor, an FG magnet provided around the main magnet, an FG signal generating unit provided in the vicinity of the FG magnet, a power A power supply control unit that controls on / off of power supply in response to a save signal; an FG amplification unit that amplifies a signal generated by the FG signal generation unit and suppresses power consumption by the power supply control unit; and the power save A latch circuit that latches the output of the FG amplifier when the signal indicates a power save, and a motor drive that generates a motor drive signal in response to a motor ON signal and whose power consumption is suppressed by the power supply control unit A signal generator, and a motor coil that receives the motor drive signal and rotationally drives the main magnet. To.
[0015]
The power control unit controls an active state and a standby state of the motor drive signal generation unit, and the power control unit controls a rotation speed control that controls the active state and the standby state of the rotation number detection signal generation unit. A circuit is configured to solve the above problems.
[0016]
When the tape feed is stopped, power is consumed by setting the rotation speed detection signal amplification section, the motor drive signal generation section, and the rotation speed detection signal generation section to a standby state according to an instruction from the power supply control section based on the stop signal Reduce.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, a latch circuit that uses a power save signal as an enable signal is provided between the FG amplification unit and the FG output terminal, and at the same time, the FG amplification unit is set in a standby state in accordance with the power save signal, and the power supply voltage is supplied to the FG signal generation unit. Since the logic value of the FG output does not change when the capstan motor is stopped, the power consumption of the FG amplification unit, the FG signal generation unit, and the motor drive signal generation unit is saved. The rotation speed control circuit is characterized in that either “H” or “L” is continuously output as the FG output.
[0018]
Next, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an example of the drive configuration of the capstan motor. FIG. 2 is a diagram for explaining a magnetoresistive element for detecting an FG signal. FIG. 3 is a diagram illustrating an example of a latch circuit, and FIG. 4 is a diagram illustrating an example of a power supply control unit. Furthermore, FIG. 5 is a timing chart for explaining the relationship between power saving and FG output.
[0019]
The capstan motor is composed of a main magnet 14 as a rotor, a magnet 15 for FG, a capstan shaft 16, a motor coil 3 as a stator, an FG signal generator 6, a housing (not shown), a shaft holder, a position detecting Hall element, and the like. Yes.
[0020]
The main magnet 14 has S and N poles alternately arranged in the plane, and when a motor ON signal is input to the input terminal 11, an appropriate motor driving signal S1 according to the state of the position detecting Hall element. Is generated by the motor drive signal generator 2 and supplied to the motor coil 3 disposed opposite to the main magnet 14 to rotate the rotor, and the magnetic tape 18 sandwiched between the capstan shaft 16 and the pinch roller 17. Runs.
[0021]
Next, an FG for detecting the number of rotations of the motor will be described in order to keep the traveling speed of the magnetic tape 18 constant and know the tape feed amount.
[0022]
The FG magnet 15 is integrally attached around the main magnet 14, and 360 S poles and N poles are alternately magnetized per round. The FG signal generator 6 arranged in close proximity picks up the magnetic flux of the FG magnet 15 and outputs an output voltage corresponding to the direction and magnitude of the magnetic field as an alternating signal of 360 waves per rotation of the rotor, at a frequency proportional to the rotational speed. Signal S2 is obtained.
[0023]
For the FG signal generator 6, a magnetoresistive element suitable for detection of a short wavelength magnetic field, for example, having a structure in which a resistor whose resistance value changes according to the magnetic flux density is bridge-connected is used.
[0024]
As shown in FIG. 2, when the power supply voltage V is applied to the terminal 20 and the terminal 21 is connected to GND, the structure of the magnetoresistive element is a resistor 24a, 24b, 24c formed of nickel iron alloy when there is no magnetic field. 24d have the same resistance value, the bridge is balanced and the output terminals 22 and 23 are at the same potential.
[0025]
Next, when a magnetic field is applied, the resistance values of the resistors 24a and 24d increase depending on the direction of the magnetic field, the resistance values of the resistors 24b and 24c decrease, and thus the bridge balance is lost. It becomes higher than the potential of 23. When a reverse magnetic field is applied, the change in resistance value of each resistor is reversed, and the potential of the output terminal 22 becomes lower than the potential of the output terminal 23.
[0026]
Since the output signal level is only about 20 mV between peaks, it is amplified by the FG amplifier 4 and shaped into a logical value level, output to the output terminal 10 through the latch circuit 5, and the next stage servo circuit and tape feed amount calculation To the microcomputer for. The latch circuit 5 constitutes a main part of the present invention.
[0027]
When the motor ON signal is not input to the input terminal 11, the motor stops. In this case, naturally, the motor driving signal S <b> 1 is unnecessary, and therefore a power save signal is input to the input terminal 12 as necessary. Then, by controlling the power supply control unit 1 and putting the motor drive signal generation unit 2 in a standby state, power consumption can be saved.
[0028]
Further, the latch circuit 5 starts the latch operation and maintains the FG output by the logical value to the output terminal 10, and at the same time, the supply of the power supply voltage to the FG signal generating unit 6 is stopped and the FG amplifying unit 4 is set in the standby state. .
[0029]
FIG. 3 shows an example of a latch circuit. When the enable input terminal 26 is “H”, a logical value input to the data input terminal 25 is output to the output terminal 27 through the NAND gate 28. When the enable input terminal 26 becomes “L”, the output logic value at that moment is output to the output terminal 27 through the NAND gate 29 and is not affected at all by the logic value of the input terminal 25.
[0030]
FIG. 4 shows an example of the power supply control unit, and the symbols of the input / output terminals in the figure are the same as the corresponding terminals in FIG. When a power supply is connected to the input terminal 13 and a negative logic power save signal is input to the input terminal 12, the controlled power supply voltage V is output to the output terminal 32.
[0031]
When the input terminal 12 is “H”, the transistor 30 is turned on and the transistor 31 is turned on, so that the power supply voltage supplied to the input terminal 13 is output to the output terminal 32 as it is.
[0032]
When the input terminal 12 is “L”, the transistor 30 is turned off and the transistor 31 is turned off, so that the power supply voltage V output from the output terminal 32 cannot supply power.
[0033]
Accordingly, the motor drive signal generator 2, the FG signal generator 6, and the FG amplifier 4 that are supplied with the power supply voltage V in FIG. 1 are in a standby state and do not consume power.
[0034]
Next, motor control will be described. As shown in the timing chart of FIG. 5, first, the motor is rotating with the power save signal “H”, the motor ON signal “H”, and the FG output alternates between “H” and “L” with the rotation. Output.
[0035]
Next, when the motor ON signal becomes “L”, the motor continues to rotate due to inertia, but gradually decelerates and eventually stops. At this time, if the motor drive signal generator has a brake function, it may be used to stop immediately.
[0036]
By setting the power save signal to “L” after the motor is stopped, the FG output is fixed by the latch, and the other units are in a standby state, thereby suppressing power consumption.
[0037]
Next, prior to motor rotation, the power save signal is set to “H” to activate each part and then the FG output latch is released, and then the motor ON signal is set to “H” to start the motor rotation. The FG output again outputs “H” and “L” alternately.
[0038]
Although the method of stopping power supply to each unit has been shown as a method for realizing the standby state, it is obvious that the method may be performed by stopping the bias supply of the circuit. In addition, as a switch for stopping power supply in the power supply control unit, it is natural that an FET that does not require a saturation voltage and a base current may be used instead of the bipolar transistor.
[0039]
【The invention's effect】
Therefore, according to the rotational speed control circuit of the present invention, by providing a latch circuit at the output of the FG amplifier, the power supply to the FG signal generator is stopped when the rotation of the capstan motor is stopped. The power consumption can be reduced by setting the amplification unit in a standby state, and the microcomputer for calculating the tape feed amount does not make a mistake in the calculation.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a drive configuration of a capstan motor.
FIG. 2 is a diagram for explaining a magnetoresistive element.
FIG. 3 is a diagram illustrating an example of a latch circuit.
FIG. 4 is a diagram illustrating an example of a power supply control unit.
FIG. 5 is a timing chart for explaining the relationship between power saving and FG output.
FIG. 6 is a diagram illustrating an example of a driving structure of a conventional capstan motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Power supply control part, 2 ... Motor drive signal generation part, 3 ... Motor coil, 4 ... FG amplification part, 5 ... Latch circuit, 6 ... FG signal generation part, 10 ... Output terminal, 11, 12, 13 ... Input terminal , 14 ... main magnet, 15 ... FG magnet, 16 ... capstan shaft, 17 ... pinch roller, 18 ... magnetic tape, 24a, 24b, 24c, 24d ... resistor, 30, 31 ... transistor

Claims (2)

A main magnet constituting the rotor;
An FG magnet provided around the main magnet;
An FG signal generator provided in the vicinity of the FG magnet;
A power control unit that controls power supply on / off in response to a power save signal;
An FG amplification unit that amplifies a signal generated by the FG signal generation unit and suppresses power consumption by the power supply control unit;
A latch circuit that latches the output of the FG amplifier when the power save signal is in a state of instructing power save;
A motor drive signal generator that receives a motor ON signal to generate a motor drive signal and that suppresses power consumption by the power supply controller;
A motor coil that receives the motor drive signal and rotationally drives the main magnet;
A motor apparatus comprising: Furthermore,
A servo circuit connected to the output terminal of the latch circuit;
A microcomputer for calculating the tape feed amount connected to the output terminal of the latch circuit;
The motor device according to claim 1, comprising:

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