JP2656122B2 - Motor drive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving device used in the fields of household electric appliances, office automation equipment, and the like.

2. Description of the Related Art Motors used in home appliances or office automation equipment have a relatively high power supply voltage, and therefore the power elements that drive the motors mounted on these equipments are subject to a large power burden and may be destroyed in some cases. There is. Therefore, a motor driving device having a function of protecting the power element is required.

As a conventional example of such a motor driving device, there is one shown in FIG. 4, for example.

Hereinafter, a conventional motor driving device will be described with reference to the drawings.

In FIG. 4, the other end of the motor 50, one end of which is connected to the positive power supply line, is connected to the collector of a transistor 52. The emitter of the transistor 52 is grounded via a current detecting means 60 and a comparator 70 Connected to the inverting input terminal. The reference signal generation source 61 is connected to the non-inverting input terminal of the comparator 70, and the output of the comparator 70 is connected to the base of the transistor 110 whose collector is grounded. The emitter of the transistor 110 is connected to a positive feed line via a resistor 111, and the transistor 52
Connected to the base. A diode 51 is connected to both terminals of the motor 50.

The operation of the conventional motor driving device configured as described above will be described below.

In FIG. 4, the voltage Vo generated by the current detecting means 60 for generating a voltage corresponding to the motor drive current is compared by the comparator 70 with the voltage Vr generated by the reference signal generator 61. First, Vo
Is smaller than Vr, the output of the comparator 70 is high, that is, substantially equal to the potential of the positive power supply line, and the transistor 110 is turned off. Transistor 110 is off
In this state, the drive transistor 52 is turned on, and a sufficient drive current is supplied to the motor. Next, when Vo becomes larger than Vr, the output of the comparator 70 falls, and accordingly, the transistor 110 starts conducting. When the transistor 110 begins to conduct, the base current of the drive transistor 52 decreases, thus operating to reduce the motor drive current. When the motor drive current decreases, Vo drops, but when Vo becomes smaller than Vr, the motor drive current increases again and Vo operates to increase, so the motor drive current is controlled so that Vo and Vr are eventually equal. Is done.

However, in the conventional configuration described above, when the motor drive current is controlled so that Vo and Vr are equal, the drive transistor 52 operates in an unsaturated state, and its collector-emitter connection Causes a large voltage to be applied. Particularly, in a motor having a high power supply voltage specification, the voltage is extremely high, and therefore, the drive transistor 52 is required to have a wide safe operation area. Such a transistor has a large shape and is expensive. Also, when operating in a non-saturated state in transistor operation, heat is generated,
It is necessary to dissipate heat.

As described above, the conventional motor driving device has various problems.

The present invention solves the above-mentioned conventional problems. Even in a motor having a high power supply voltage specification, it is possible to apply a transistor having a small shape, a low cost, and a narrow safe operation area, and furthermore, the heat generation amount is small and there is no need for heat dissipation. An object of the present invention is to provide a motor driving device.

Means for Solving the Problems To achieve this object, a motor driving device according to the present invention includes a driving transistor for energizing a motor, current detecting means for detecting a driving current of the motor, a reference signal generating source, A comparator for comparing the output of the current detection means with the output of the reference signal generator, a clock signal generator, and a flip-flop that is set by the output of the comparator and reset by the clock output of the clock signal generator When the flip-flop circuit is set, the energization of the drive transistor is stopped,
When the flip-flop circuit is reset, the drive transistor is energized.

Operation With this configuration, the drive transistor is controlled in either the energized state or the stopped state. That is,
The driving transistor is controlled by ON / OFF operation, and compared to the operation in the unsaturated region as shown in the conventional example, the safe operation region can be applied to a transistor which is much narrower.
It is also extremely advantageous in terms of heat generation.

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

FIG. 1 is a circuit diagram showing a driving position of a motor according to a first embodiment of the present invention. The same numbers are given to the same names as those described in the conventional example. First
In the figure, a motor 50 having one end connected to the positive feeder line is shown.
Is connected to the collector of a transistor 52, and the emitter of the transistor 52 is grounded via a current detecting means 60 and connected to the inverting input terminal of a comparator 70. The non-inverting input terminal of the comparator 70 has a reference signal source
The output of the comparator 70 is input to the S input of the flip-flop circuit 80. Clock signal generator
The output of the flip-flop circuit 80 is input to the R input of the flip-flop circuit 80, and the output of the flip-flop circuit 80 is input to the base of the transistor 101 whose emitter is grounded and connected to the positive power supply line via the resistor 100. Have been.
The collector of the transistor 101 is connected to a positive power supply line via a resistor 102 and the driving transistor 52
Connected to the base.

Regarding the motor driving device configured as described above,
The operation will be described below.

First, when the voltage Vo generated by the current detection means 60 is lower than the voltage Vr generated by the reference signal generation source 61, the output voltage of the comparator 70, that is, the set input S of the flip-flop circuit 80 is high.
Becomes On the other hand, a clock pulse is always input to the set input R of the flip-flop circuit 80 by the clock signal generator 90. Here, the flip-flop circuit 80
The output of Hig when the set input S changes from High to Low
h, when the reset input R changes from High to Low
It is configured to be w. Accordingly, as described above, when the set input S of the flip-flop circuit 80 is high and a clock pulse that changes from high to low is input to the set input R, the output goes low. Therefore, the transistor 101 turns off and the drive transistor 52 turns on. When the drive transistor 52 is turned on, a drive current is supplied to the motor 50.

Next, when the voltage Vo generated by the current detecting means 60 becomes higher than the voltage Vr generated by the reference signal generating source 61, the output voltage of the comparator 70, that is, the set input S of the flip-flop circuit 80 becomes Lo.
becomes w. At this time, assuming that the reset input R is High, the output of the flip-flop circuit 80 becomes High, and the transistor 101 turns ON. When the transistor 101 is turned on, the drive transistor 52 is turned off, and the drive current of the motor 50 is cut off. When the driving current of the motor 50 is cut off, the generated voltage Vo of the current detecting means 60 decreases, and the output of the comparator 70, that is, the set input S of the flip-flop circuit 80 becomes High.
In this state, when the reset input R changes from High to Low by the output of the clock signal generator 90, the output of the flip-flop circuit 80 becomes Low and the transistor 101
Turn off. When the transistor 101 is turned off, the drive transistor 52 is turned on, and a drive current is supplied to the motor 50. That is, when the motor drive current decreases, the drive transistor 52
Drive current continues to be supplied to the motor, but when the motor drive current increases, this is detected by the current detection means 60, the reference signal generation source 61, and the comparator 70, and the flip-flop circuit 80 is set, and the drive transistor 52 To OFF.
When a clock pulse is generated from the clock signal generator 90, the flip-flop circuit 80 is reset, and the driving transistor 52 is turned on again. The motor drive current is controlled so that the drive transistor 52 performs such ON / OFF operation.

As described above, according to the present embodiment, when controlling the motor drive current, the drive transistor 52 is configured to perform ON / OFF operation. Can be applied. Further, since the ON / OFF operation is performed, the amount of heat generation is small, and there is no need for heat radiation.

In this embodiment, the motor 50 may be replaced with a brushless motor, for example, a motor having a configuration as shown in FIG. In this case, the drive transistors 13, 14, and 15 are turned ON / OFF via the transistor 105 according to the set and reset states of the flip-flop circuit 80, and the motor drive current is controlled.

Further, if the brushless motor is a so-called commutation sensorless brushless motor (hereinafter referred to as a sensorless brushless motor) having no mover position detector,
A clock pulse corresponding to the output of the oscillator, which is a component necessary for starting the motor or the like, may be input to the reset input R of the flip-flop circuit 80. In this case, the clock signal generator 90 becomes unnecessary. As such a specific embodiment, for example, the one shown in FIG. 3 can be considered. In FIG. 3, the output frequency f of the oscillator 40 is
Divides by the flip-flop circuit 80 and the divided output D ₃
Reset input R.

As described above, when the motor drive current increases, the present invention sets the flip-flop circuit to turn off the drive transistor, and resets the flip-flop circuit by an appropriate clock pulse signal to thereby reset the drive transistor. Is turned on again, so that the drive transistor is turned on / off. This makes it possible to apply an inexpensive and small-sized drive transistor having a narrow safe operation area, a small self-heating, and no need for heat radiation.
In particular, when driving ICs with built-in drive transistors,
It is possible to realize an excellent motor driving device that can reduce the proportion of the driving transistor occupied in the chip and can also provide a cost advantage by reducing the chip size.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a motor driving device according to a first embodiment of the present invention, FIG. 2 is a circuit configuration diagram of a motor driving device according to a second embodiment of the present invention, and FIG. FIG. 4 is a circuit configuration diagram of a motor driving device according to the third embodiment, and FIG. 4 is a circuit configuration diagram of a motor driving device according to a conventional example. 1-3: motor drive coil, 10-15: drive transistor, 40: oscillator, 44: current switching circuit, 45: commutation circuit, 50: motor, 52: drive transistor, 60:
Current detection means, 61 ... reference signal source, 70 ... comparator,
80: Flip-flop circuit, 90: Clock signal generator.

(72) Inventor Masao Mizumoto 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Juichi Uno 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric (56) References JP-A-1-202197 (JP, A)

Claims (3)

(57) [Claims] 1. A motor, a drive transistor for continuously energizing and driving the motor, current detecting means for detecting a driving current of the motor, a reference signal generating source, and an output of the current detecting means for outputting the reference signal. A comparator for outputting a signal when the output of the source is exceeded, a flip-flop circuit having two inputs, set and reset, set by the output of the comparator, and a clock for repeatedly resetting the flip-flop circuit A signal generator, continuously energizing the drive transistor while the flip-flop circuit is not set by the comparator output, and energizing the drive transistor when the flip-flop circuit is set by the comparator output. The clock is temporarily stopped, and the flip-flop circuit is reset by the clock output of the clock signal generator. Configuration the motor of the driving device so as again energized the driving transistor when the bets. 2. A motor drive coil having a plurality of phases, a commutation circuit for generating an energization switching signal for the driving coil, and a plurality of commutation circuits connected to the driving coil for sequentially transmitting the energization switching signal for the commutation circuit. A drive transistor, wherein the drive transistor drives the motor drive coil by continuously energizing the drive transistor while the energization switching number is transmitted, and a current detecting means for detecting a drive current of the drive coil; A signal generator, a comparator for outputting a signal when the output of the current detector exceeds the output of the reference signal utterance source, and a flip-flop having two inputs, set and reset, set by the comparator output A flip-flop circuit, and a clock signal generator for repeatedly resetting the flip-flop circuit. When the plurality of driving transistors are not turned on, the plurality of driving transistors are sequentially switched on by the conduction switching signal from the commutation circuit to supply current. When the flip-flop circuit is set by the comparator output, all the plurality of driving transistors are supplied with current. A motor which is configured to temporarily stop the plurality of drive transistors when the flip-flop circuit is reset by the clock output of the clock signal generator and to sequentially switch on the plurality of drive transistors again by the switch-on signal from the commutation circuit. Drive. 3. A multi-phase motor drive coil, an oscillator,
An output of the oscillator is input, an energization switching circuit that generates an energization switching signal for the driving coil in accordance with an induced voltage generated in the driving coil, and an energization switching signal connected to the driving coil, the energization switching signal of the energization switching circuit. A plurality of drive transistors sequentially transmitted, and the drive transistor drives the motor drive coil by continuously energizing while the energization switching signal is transmitted, and detects a drive current of the drive coil. A current detection unit, a reference signal generation source, a comparator that outputs a signal when an output of the current detection unit exceeds an output of the reference signal generation source, and two inputs of set and reset; A flip-flop circuit set by an output and repeatedly reset by a clock signal corresponding to the oscillator output; While the path is not set by the comparator output, the plurality of drive transistors are sequentially switched and energized by an energization switching signal from the energization switching circuit, and when the flip-flop circuit is set by the comparator output, the plurality of drive transistors are energized. All the drive transistors are temporarily stopped, and when the flip-flop circuit is reset by a clock output corresponding to the oscillator output, the plurality of drive transistors are sequentially switched again by the switch signal from the switch circuit. A motor drive device configured to be energized.