JPH0828991B2 - Brushless motor drive - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for a brushless motor used in audio visual equipment and the like.

2. Description of the Related Art In recent years, drive motors for audio equipment, video equipment, etc. have been equipped with mechanical switches such as brushes and commutators in order to extend their service life, increase reliability, and reduce their shape. A so-called brushless motor having an electronic switch using a transistor has been increasingly used instead of the motor. As a conventional technique for such a brushless motor driving device, for example, Japanese Patent Publication No. 59-2719
There is one as shown in FIG.

Hereinafter, an example of the above-described conventional brushless motor driving device will be described with reference to the drawings.

FIG. 4 is a circuit connection diagram of a conventional drive device for a brushless motor. In FIG. 4, reference numerals 1 to 3 are mover position detectors, which are constituted by Hall elements, for example. The transistors 7 and 8 form a pair of differential transistors, and the output of the position detector 2 is connected to the base input. The transistors 9 and 10 form a pair of differential transistors, and the output of the position detector 1 is connected to the base input. The transistors 5 and 6 form a pair of differential transistors, and the output of the position detector 3 is connected to the base input. The common emitter of the transistor pair 5,6 is connected to the constant current source 4, the common emitter of the transistor pair 7,8 is connected to the collector of the transistor 5,
The common emitter of the transistor pair 9, 10 is connected to the collector of the transistor 6. The transistor
The collectors of 7, 10 are both connected to the base of the transistor 12, the collector of the transistor 8 is connected to the base of the transistor 11, and the collector of the transistor 9 is connected to the base of the transistor 13. The collectors of the transistors 11 to 13 are connected to drive coils 14 to 16 of a motor (not shown), and the emitters of the transistors 11 to 13 are connected to the positive power supply line.

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

FIG. 5 is a diagram for explaining the operation in FIG. 4, in which the position detector of the mover outputs a signal having a 120 ° phase difference as shown by A to C. First, the transistors 7, 8 and 9, 10
At the base inputs of 5 and 6, the position detector output is A
When>, B <, C>, the output current of the constant current source 4 is supplied to the base of the transistor 12 through the transistors 5 and 7, and the transistor 12 is turned on and the drive coil 15 is energized. When A>, B <, C <, the output current of the constant current source 4 is supplied to the base of the transistor 12 through the transistors 6 and 10, and the transistor 12 continues to be in the ON state and the drive coil 15 is energized. A>, B>, C <and A <
, B>, C <, the output current of the constant current source 4 is supplied to the base of the transistor 13 through the transistors 6 and 9, and the transistor 13 is turned on and the drive coil 16 is energized. When A <, B>, C> and A <, B <, C>, the output current of the constant current source 4 is supplied to the base of the transistor 11 through the transistors 5 and 8, and
11 is turned on and the drive coil 14 is energized. As described above, the drive coils 14 to 16 are sequentially energized to drive the motor.

Problems to be Solved by the Invention However, in the above configuration, when the power supply voltage is low, for example, about 1 V, the base-emitter voltage of each transistor is 0.7 V and the collector-emitter saturation voltage is 0.1 V. Then, there is no margin in circuit operation. If there is a margin in operation, the voltage applied to each base of the differential transistor pair 5 and 6 needs to be 0.8 V or higher, and similarly, the voltage of the differential transistor pair 7, 8 and 9 and 10 is required. The applied voltage of each base must be 0.9V or higher. Therefore, the drive power supply voltage V _H of the position detectors 1 to 3 needs to be 1 V or higher,
1V single power supply operation becomes impossible. Therefore, a method of configuring each differential transistor pair in FIG. 4 with PNP is conceivable. In this case, the base applied voltage of each differential transistor pair is a value obtained by subtracting 0.8V and 0.9V from the power supply voltage (1V), that is, Must be 0.2V and 0.1V or less. Therefore, the drive voltage V _H of the position detector is 1 V or less and the power supply voltage or less,
A single 1V power supply operation is possible at first glance. However, if the base applied voltage of the differential transistor pair is about 0.1 V, the drive voltage of the position detector becomes extremely small, and it becomes impossible to obtain a sufficient output as the position detector.

As described above, the conventional brushless motor driving device, in the 1V single power supply operation, not only there is no margin in the circuit operation, and the input unit of the position detection signal processing circuit composed of the differential transistor pair, Various problems occurred when the position detector output part was connected.

In view of the above problems, the present invention provides a drive device for a brushless motor that can operate with a single 1V power source.

Means for Solving the Problems In order to solve the above problems, a brushless motor driving device according to the present invention includes a plurality of motor driving coils, a plurality of driving transistors, a mover position detector, and the position detecting device. And a level conversion circuit provided between the position detector and the position detection signal processing circuit, the position detection signal processing circuit generating an energization command signal to the drive transistor according to the output of the device.

Effect of the Invention The present invention provides the level conversion circuit between the position detector and the position detection signal processing circuit, so that the position detector output is transmitted to the position detection signal processing circuit input at a low power supply voltage. Even if the drive voltage of is maximally applied within the power supply voltage, it can be transmitted to the position detection signal processing circuit by appropriately converting the level of the position detector output. That is, even with a low power supply voltage, a sufficient detection signal as a position detector can be transmitted to the position detection signal processing circuit.

Embodiment A drive device for a breathless motor according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of a brushless motor driving device according to an embodiment of the present invention. In FIG. 1, reference numerals 21, 22, 23 denote mover position detectors, which are constituted by Hall elements, for example. The position detectors 21-23
Are connected in parallel to the position detector driving power supply 24. The outputs of the constant current sources 31 and 37 are connected via a resistor 43, the outputs of the constant current sources 32 and 38 are connected via a resistor 44, and the outputs of the constant current sources 33 and 39 are connected via a resistor 45. The outputs of the constant current sources 34 and 40 are connected via a resistor 46, the outputs of the constant current sources 35 and 41 are connected via a resistor 47, and the outputs of the constant current sources 36 and 42 are connected to each other. Connected via resistor 48. The constant current sources 31 to 42 and the resistors 43 to 48 form a level conversion circuit 30. One output of the position detector 21 is connected to the output of the constant current source 31, the other output is connected to the output of the constant current source 32, 22 of the position detector.
One output is connected to the output of the constant current source 33, the other output is connected to the output of the constant current source 34, one output of the position detector 23 is connected to the output of the constant current source 35. The other output is connected to the output of the constant current source 36. The base inputs of the differential transistor pair 57, 58 are connected to the outputs of the constant current sources 37, 38, and the common emitter is connected to the positive side feed line 20 via the constant current source 51. Each base input of the differential transistor pair 59, 60 is the constant current source 39,
The common emitter is connected to each output of 40, and the common emitter is connected to the positive side feed line 20 through a constant current source 52. The base inputs of the differential transistor pair 61, 62 are connected to the outputs of the constant current sources 41, 42, and the common emitter is connected to the positive side feed line 20 via the constant current source 53. The transistor
The collectors of 57 and 62 are commonly grounded via the constant current source 54 and are connected to the emitter of the transistor 63. The collectors of the transistors 58 and 59 are commonly grounded via the constant current source 55 and connected to the emitter of the transistor 64. The collectors of the transistors 60 and 61 are commonly grounded via a constant current source 56 and connected to the emitter of a transistor 65. The collector of the transistor 63 is connected to the base and collector of the transistor 67 and the base of the transistor 68, and the collector of the transistor 64 is a transistor.
It is connected to the base and collector of 69 and to the base of transistor 70, and the collector of the transistor 65 is connected to the base and collector of transistor 71 and the base of transistor 72.
The bases of the transistors 63 to 65 are both bias power supplies.
The emitters of the transistors 67 to 72 are connected to the positive side feed line 20. The collectors of the transistors 68, 70, 72 are connected to the outputs of the constant current sources 73, 74, 75, and are input to the forward / reverse rotation switching circuit 80. The outputs U, V, W of the normal / reverse rotation switching circuit 80 are transistors 151, 152, whose emitters are connected to the positive side power supply line 20, respectively.
The transistors 151 to 153 are connected to the respective bases of 153.
Each collector has a grounded emitter transistor 154-1
It is connected to each base of 56 and is grounded through resistors 157 to 159. The collectors of the transistors 154 to 156 are connected to one ends of the motor drive coils 201 to 203, respectively, and the other ends of the motor drive coils 201 to 203 are connected to the positive side feed line 20.

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

FIG. 2 is a specific circuit connection diagram of the level conversion circuit 30 and the position detection signal processing circuit input section for the position detector 21 of FIG. 1, and those having the same functions as those in FIG. , And the description thereof is omitted. In FIG. 2, assuming that the output current of the constant current source 45 is Is, the output currents of the transistors 31, 32, 37, 38 operating as the constant current source are substantially equal to Is. Therefore, the output current of the transistor 31 is absorbed by the transistor 37 through the resistor 43 without excess or deficiency. That is, a voltage drop due to Is occurs at both ends of the resistor 43, and one end of the position detector 21 is connected to the resistor 43.
By connecting to one end of the resistor 43, the DC level converted output of one end of the position detector 21 can be obtained at the other end of the resistor 43. The same applies to the other end of the position detector 21. This is shown in FIG.

On the other hand, the base input voltage range of the differential transistor pair 57, 58 that composes the input part of the position detection signal processing circuit is as follows:
Assuming that the emitter saturation voltage is 0.1V, 0V to power supply voltage −0.8V
And becomes 0V to 0.2V when the power supply voltage is 1.0V. Therefore, the DC bias voltage of a _S and _S is about 0.15V,
Position detector drive power supply 24 to obtain sufficient position detector output
Even if the applied voltage of is increased, Is and resistance 4
By adjusting the values of 3,44 and adjusting the level conversion amount, the position detector output can be transmitted to the position detection signal processing circuit. Similarly, in the position detectors 22 and 23, each output can be transmitted to the position detection signal processing circuit. The position detection signal transmitted to the position detection signal processing circuit 50 as described above passes through the forward / reverse rotation switching circuit 80 and the driving transistor 151.
To 156 are sequentially turned on to supply electric power to the motor drive coils 201 to 203 to drive the motor. The state is the same as the operation explanatory view of the conventional example shown in FIG.

As described above, according to this embodiment, by providing the level conversion circuit between the position detector and the position detection signal processing circuit, the position detector output can be effectively output even at a low power supply voltage of 1V. It can be transmitted to the processing circuit and can exhibit extremely excellent performance as a driving device for an ultra-low voltage brushless motor.

As described above, according to the present invention, by providing the level shift circuit at the position detector output, when the position detector output and the position detection signal processing circuit input are coupled, the setting of the DC bias voltage and the required position Problems such as securing the detector output can be eliminated, and an excellent effect can be obtained especially in ultra-low voltage operation.

[Brief description of drawings]

FIG. 1 is a circuit connection diagram of a brushless motor drive device according to an embodiment of the present invention, and FIG. 2 is a specific circuit connection diagram of a level conversion circuit and a position detection signal processing circuit input section.
2 is an operation explanatory diagram in FIG. 2, FIG. 4 is a circuit connection diagram of a conventional brushless motor driving device, and FIG. 5 is an operation explanatory diagram in FIG. 21-23 ... Position detector, 30 ... Level conversion circuit, 31-36
...... Current supply means, 37 to 42 ...... Current absorption means, 43 to 48 ...
… Resistance, 50 …… Position detection signal processing circuit, 151 ～ 156 …… Drive transistor, 201 ～ 203 …… Motor drive coil.

Claims (1)

[Claims] 1. A multi-phase motor drive coil, a plurality of drive transistors, a mover position detector, and position detection signal processing for generating an energization command signal to the drive transistor according to the output of the position detector. A circuit and a level conversion circuit provided between the position detector and the position detection signal processing circuit for converting a direct current level of the position detector output, the level conversion circuit being a current supply means, and the current A brushless motor drive device comprising a current absorbing means for absorbing all output current of the supplying means, and a resistor connecting the current supplying means and the current absorbing means.