JPS61247289A - Operating circuit for dc motor - Google Patents

Abstract

PURPOSE:To eliminate a switching element of a large rated value for an arma ture coil driver by providing a switching element to energize or deenergize a controller for controlling the armature coil driver. CONSTITUTION:When a start switch 28 is closed, a transistor 27 is turned ON to energize a controller 24. As a result, a rotating position detector 25 and a rotating speed controller 26 operate to control an armature coil driver 20. An armature coil 13 is controlled to be energized or deenergized by the driver 20 to rotate a rotor 1 as prescribed. When the switch 28 is opened, the operation of the motor is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a DC motor operation circuit having an armature coil drive circuit and a control circuit for controlling the armature coil drive circuit.

[Technical background of the invention] FIG. 4 shows the operating circuit of a conventional DC motor.

In the figure, 1 is an armature coil, 2 is an armature coil drive circuit that drives this armature coil 1, and 3 is a control circuit that controls this armature coil drive circuit 2. This control circuit 3 is, for example, a rotational position detection circuit 4. and a rotation speed control circuit 5. Reference numeral 6 denotes a PNP type transistor serving as a switching element, which allows the armature coil drive circuit 2 and the control circuit 3 to be electrically disconnected. Therefore, in this one,
When the transistor 6 is turned on, a power supply voltage is applied to the armature coil drive circuit 2 to enable the armature coil drive circuit 2 to function, and a power supply voltage is applied to the control circuit 3 to enable the control device 3. functions to control the armature coil drive circuit 2, and the armature coil drive circuit 2 turns on or off the armature coil 1 based on this.

[Problems with the Background Art] However, in the above conventional case, since both the armature coil drive circuit 2 and the control circuit 3 are turned on and off by the transistor 6, the transistor 6, which is a switching element,
As a result, a power transistor with a large current rating must be used, which increases the cost and requires a large space for the circuit configuration.
Since the transistor 6 is present in the current supply path to the armature coil 1, there is a problem that the voltage applied to the armature coil 1 in the armature coil drive circuit 2 is lost by the forward voltage drop of the transistor 6.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to reduce the cost, reduce the circuit configuration space, and reduce the loss of voltage applied to the armature coil. The purpose of the present invention is to provide a DC motor driving circuit that can eliminate the problem.

[Summary of the Invention] The present invention includes an armature coil drive circuit that can function by applying a power supply voltage, and a control circuit that controls the armature coil drive circuit.
By configuring the control circuit to include a switching element so as to turn off the current, it is possible to use a switching element with a small rating.

[Embodiments of the Invention] A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 2 shows the configuration of a DC motor, for example, a floppy disk drive motor. In the figure, 11 is a stator, which includes a magnetic substrate 12, a three-phase armature coil 13, three Hall elements 14. Various electronic components 15, frequency power generation coil patterns (not shown), etc. are attached. 16 is a rotor, which is constructed by attaching a rotor magnet 18 and a frequency power generation magnet 19 to a rotor yoke 17. Next, FIG. 1 shows an operating circuit, and in the same figure, 20 is an armature fill drive circuit that drives the armature coil 13, and this is connected to a DC power supply terminal 21 of voltage VCC, which is a DC power supply, via a power line 22. It is connected. This armadure coil drive circuit 20 is enabled to function in this state where the power supply voltage ycc is applied. Note that 23 is an L-shaped filter provided on this power line 22. Reference numeral 24 denotes a control circuit, which includes a rotational position detection circuit 25 which is formed by connecting the Hall elements 14 in series and outputs a position detection signal according to the rotational position of the rotor 16, and the frequency coil pattern and the frequency power generation magnet. The rotating speed control circuit 26 outputs a speed control signal based on the frequency signal from the frequency generator 19. The armature coil drive circuit 20 is controlled based on the position detection signal given from the rotational position detection circuit 25 and the speed control signal given from the rotational speed control circuit 26 to turn on and off the armature coil 13 in a predetermined mode. It looks like it's going to be powered up. 27 is a PNP which is a switching element
type transistor, whose emitter is connected to the power supply line 2
2, its collector is connected to the rotational position detection circuit 25 and rotational speed control circuit 26 in the control circuit 24, and the base of the transistor 27 is connected to ground via the start switch 28. In addition, 29.30
is the base resistance.

In such a configuration, when the start switch 28 is turned on, the transistor 27 is turned on and the control circuit 24 is energized, and as a result, the rotational position detection circuit 25 and the rotational speed control circuit 26 function, and the armature coil drive circuit 20 The armature coil drive circuit 20 controls the armature coil 13 to be energized and de-energized in a predetermined manner to rotate the rotor 16 in a predetermined manner, thereby operating the motor. When stopping the operation of the motor, the control circuit 24 is cut off by opening the start switch 28 and turning off the transistor 27, and the rotational position detection circuit 25 and the rotational speed control circuit 26 in the control circuit 24 are All you have to do is stop the function.

According to this embodiment, the transistor 27 is provided to turn on and off the control circuit 24, and the transistor 27
The 1lJIj circuit 24 starts functioning by turning on and off.
By starting the function of the control circuit 24 and stopping the function, the armature coil drive circuit 20
Since the armature coil drive circuit 20 is configured to drive and stop, there is no need to provide a switching element for the armature coil drive circuit 20, and therefore, there is no need for a conventional power transistor. 27 is also fine with a small rating.

Therefore, the cost can be reduced, the circuit configuration space can be reduced, and loss of voltage applied to the armature coil 13 can be eliminated.

Next, FIG. 3 shows a second embodiment of the present invention, in which the rotational speed control circuit 31 is provided with a standby function, and the standby function is performed by a transistor 27.
The switch is activated and deactivated by turning it on and off. That is, the rotational speed control circuit 31 is connected to the power supply line 22 without going through the transistor 27,
The standby terminal 31a is connected to a common connection point between the base of the transistor 27 and the start switch 28, and when the input voltage of the standby terminal 31a becomes low level, the rotation speed control circuit 31 is activated.
Therefore, the transistor 27 is turned on.

OFF Therefore, the function start 1 function is stopped in synchronization with the function start 9 function stop of the rotation detection circuit 25. According to this second embodiment, there is an advantage that the rating of the transistor 27 can be further reduced.

In each of the above embodiments, the Hall elements 14 are connected in series, but they may be connected in parallel.

In addition, the present invention is not limited to the above embodiments, and can be implemented with various modifications without departing from the scope of the invention.

[Effects of the Invention] As is clear from the above description, the present invention can eliminate the need for conventional high-rated switching elements for the armature coil drive circuit, and use small-rated switching elements for the control circuit. Therefore, it is possible to reduce the cost, reduce the space of the circuit configuration, and eliminate loss of voltage applied to the armature coil, which provides excellent effects.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention, with FIG. 1 being an electric circuit diagram and FIG. 2 being a longitudinal sectional side view of the entire motor. FIG. 3 is a diagram corresponding to FIG. 1 showing a second embodiment of the present invention. FIG. 4 is a diagram corresponding to FIG. 1 showing a conventional example. In the figure, 11 is a stator, 13 is an armature coil, 1
4 is a Hall element, 16 is a rotor, 18 is a rotor magnet, 19 is a frequency power generation magnet, 20 is an armature coil drive circuit, 24 is a control circuit, 25 is a rotational position detection circuit, 26 is a rotational speed control circuit, 27 is a transistor (switching element), 31 is a rotational speed control circuit. Figure 1 *2 [2

Claims (1)

[Scope of Claims] 1. An armature coil drive circuit that can function by applying a power supply voltage, a control circuit that controls this armature coil drive circuit, and a switching element that turns off current to this control circuit. A DC motor driving circuit consisting of: 2. The DC motor driving circuit according to claim 1, wherein the control circuit comprises a rotational position detection circuit and a rotational speed control circuit. 3. The DC motor driving circuit according to claim 2, wherein the rotational speed control circuit has a standby function that is activated and deactivated when a switching element is turned on and off.