JPH06133587A - Motor driver - Google Patents

Abstract

PURPOSE:To provide a motor driver which is suitable when the power supply voltage is low or for driving a motor having a large DC resistance component. CONSTITUTION:A feedback loop is constituted of a comparator 1, conduction switching circuit 2, transistors 18-20 for sensors, current detecting resistor 6, and voltage difference detector 202 so that a voltage drop can be generated across the terminals of the resistor 6 corresponding to the electric current flowing through each winding 9-11 and can be inputted to the detector 202, and then, the output of the detector 202 can be inputted to the noninverted input terminal of the comparator 1 for feedback.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving device suitable for driving a motor driven by a low power supply voltage and a motor having a large resistance component.

[0002]

2. Description of the Related Art In recent years, in order to control the number of rotations of a motor and to improve load characteristics, a motor drive device has been used which supplies a voltage to a motor by applying a voltage according to a required torque and converting the current. Came.

A conventional motor drive device using a three-phase half-wave motor will be described below. FIG. 4 is a configuration diagram of a conventional motor drive device, 1 is a comparator, 2 is an energization switching circuit, 3 to 5 are motor position detection elements such as hall elements,
6 is a current detection resistor, 7 is a power supply voltage terminal, 8 is a torque command input terminal, 9 to 11 are motor windings, and 12 to 14 are output transistors.

FIG. 6 shows signal waveforms at various points in a conventional three-phase half-wave motor driving device. In this motor drive device, first, a voltage corresponding to a desired current flowing in the field winding of the motor is input from the torque command input terminal 8 and the comparator 1
Set the voltage at the non-inverting input terminal of. Next, the energization switching circuit 2
Switch signal H _U Hall elements 3 to 5, H _V, the output of the comparator 1 in accordance with the H _W, the output transistor 12 to 14
The drive signals U _d , V _d , and W _d are output to the base of the output transistor 12 to drive the output transistors 12 to 14. And windings 9-11
And a current is passed through the current detection resistor 6. The current is sequentially switched like winding currents I _U , I _V , and I _W. The current I _RCS flowing through the current detection resistor 6 is a combined current obtained by adding the winding currents I _U , I _V , and I _W. The detection resistor 6 generates a current detection voltage according to the current I _RCS and negatively feeds back the current detection voltage to the comparator 1. The comparator 1 compares the input voltage with the current detection voltage and drives the output transistors 12 to 14 so that they are the same. As a result, a current corresponding to the input voltage of the torque command flows through the windings 9 to 11.

[0005]

However, in the above-described conventional configuration, since there is a current detection voltage generated in the current detection resistor 6, if the power supply voltage is constant, an effective load voltage that can be used in the windings 9 to 11 is obtained. Has a problem that the current detection voltage generated in the current detection resistor 6 is damaged.
This means that in recent years, motors that drive headphone stereos, floppy disk devices, etc. have been downsized and the voltage has been reduced. However, there has been a demand for a motor drive device that can obtain a sufficient torque.

Further, the current detection resistor 6 is usually as low as about 1 Ω and requires high precision, and the wiring resistance component of the wiring pattern cannot be ignored, and there is a restriction that it must be connected by a thick and short wiring. It was Further, since the resistance value is too small, the area of the resistance becomes large when the resistance value is formed in the semiconductor integrated circuit, and the integration degree of the semiconductor integrated circuit deteriorates.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a motor drive device suitable for a motor having a low power supply voltage and a large resistance component.

[0008]

In order to achieve this object, a motor drive device according to the present invention has an n-type common connection at one end.
Phase motor windings, n output transistors whose collectors are connected to the other ends of the windings, n sensor transistors current-mirror coupled to each output transistor, and collectors of each sensor transistor Of the resistor connected to the common connection point of the resistor, the DC voltage unit connected to the other end of the resistor, the speed detection device for instructing the switch to short-circuit the output of the DC voltage unit, and the both ends of the resistor. Voltage difference detector that detects the voltage difference of the voltage output, a comparator that outputs the error signal by comparing the output of the voltage difference detector and the torque command signal, and according to the change of the rotating magnetic field of the motor magnet. , And an energization switching circuit that switches the error signal for each phase and supplies it to each base of the n output transistors.

[0009]

With this configuration, the switch is turned on by the output of the speed detection device until the motor reaches a predetermined number of rotations, and the output of the DC voltage generator is short-circuited, and the other end of the current detection resistor is connected. By connecting to the power supply voltage terminal, the current detection resistor that detects the current in the motor winding can be inserted in the collector circuit of the sensor transistor that is mirror-coupled to the output transistor that drives the current in the motor winding. Since the current detection voltage drop does not become a factor that limits the voltage applied to the motor winding,
A large amount of voltage can be applied to the winding. For this reason, a large amount of current can flow if the winding resistance is the same, so that the torque of the motor can be increased, and the winding can be thinned to reduce the size of the motor.

When the motor reaches a predetermined number of rotations, the switch is turned off by the output of the speed detecting device, and the output of the DC voltmeter is added to the voltage of the current detecting resistor to increase the voltage drop. As a result, when the motor reaches a predetermined number of revolutions, the counter electromotive voltage generated from the motor causes the collector voltage value of the output transistor in the ON state and the collector voltage of the sensor transistor to be at substantially the same potential. . In other words, by making the collector voltage of the sensor transistor and the collector voltage of the output transistor at a predetermined number of rotations of the motor substantially the same potential, it is possible to prevent the deviation of the current ratio due to the Early effect of the transistor and to stably rotate the motor. .

If the mirror ratio between the output transistor and the sensor transistor is increased, the current detection resistance can be set to a resistance value of several hundred Ω to several kΩ, so that the current detection resistor is built in the semiconductor integrated circuit device. It becomes possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. This embodiment is an apparatus for driving a three-phase half-wave motor.

In FIG. 1, 1 is a comparator, 2 is an energization switching circuit, and 3 to 5 are Hall elements for detecting a rotating magnetic field generated by rotation of a rotor of a motor. 6 is a current detection resistor that generates a voltage drop corresponding to the current of the motor winding,
7 is a power supply voltage terminal, 8 is a torque command input terminal, and 9 to 11
Are windings for motors, and 12 to 14 are output transistors, which respectively drive the windings 9 to 11 connected to the collector. Reference numerals 18 to 20 denote sensor transistors whose bases and emitters are connected to the bases and emitters of the output transistors 12 to 14, respectively. Reference numeral 200 is a DC voltage generator, 201 is a speed detection device for detecting the number of rotations of the motor, and 203 is a switch for outputting the output voltage of the DC voltage device or short-circuiting the output of the speed detection device. . A voltage difference detector 202 detects a voltage difference applied across the current detection resistor 6.

A set voltage corresponding to a desired current flowing through the motor winding is applied from the torque command input terminal 8 to the inverting input terminal of the comparator 1, and the voltage drop generated by the current detecting resistor 6 is a voltage difference. The voltage difference detector 2 is provided to the detector 202.
The output of 02 is given to the non-inverting input terminal of the comparator 1, and the comparator 1 amplifies the compared input voltage and outputs an error signal.

The hall elements 3 to 5 are arranged at an electrical angle of 120 degrees with respect to the rotation axis of the motor, detect the rotating magnetic field of the motor, and output a hall signal.

The energization switching circuit 2 switches the error signal for each phase of the windings 9 to 11 according to the Hall signal that detects the change in the rotating magnetic field of the motor, and outputs transistors 12 to 14 respectively.
An error signal switched at a conduction angle of 120 degrees is applied to each of the bases.

The output transistors 12 to 14 are connected to the respective windings 9 to 11 at their collectors, and are sequentially turned on at an energization angle of 120 degrees by the output signal of the energization switching circuit 2.

The sensor transistors 18 to 20 have their bases and emitters connected to the bases and emitters of the output transistors 12 to 14, respectively, and have collector currents of a predetermined ratio to the collector currents of the output transistors 12 to 14. The collectors are electrically connected and the collectors are commonly connected, and the current detection resistor 6 is connected to the common connection point of the collectors. Speed detection device 201 for detecting a predetermined motor rotation speed
Are connected to output to the switch 203 and output or short circuit the output voltage of the DC voltage generator 200.

As described above, the motor drive device of this embodiment includes the comparator 1, the energization switching circuit 2, the sensor transistors 18 to 20, the current detection resistor 6, and the voltage difference detector 20.
2 forms a feedback loop, generates a voltage drop corresponding to the current flowing in each winding 9 to 11 between the terminals of the current detection resistor 6, inputs the voltage between the terminals to the voltage difference detector 202, and detects the voltage difference. The output of the device 202 is input to the non-inverting input terminal of the comparator 1 to perform negative feedback.

The operation of the motor drive device of the present embodiment constructed as above will be described below.

The signal waveform at each point is almost the same as the signal waveform of the conventional example shown in FIG. 6, so that the description will be given below with reference to FIG.

First, when a voltage corresponding to a desired current flowing through the motor winding is input from the torque command input terminal 8 to the non-inverting input terminal of the comparator 1, the comparator 1 amplifies and outputs the voltage. Next, energization switching circuit 2 Hall element signals H _U obtained by the Hall element 3 to 5, H _V, the comparator in response to H _W 1
Of the drive signals U _d , V _d , and W _d are applied to the output transistors 12 to 14 by switching the output. Then, the output transistor 12 to 14, the drive signal U _d, rendered conductive in response to V _d, W _d, winding 9-11 the winding current I _U, I _V, to drive the I _W. The current switches like winding currents I _U , I _V , and I _W. In addition, sensor transistors 18 to 20
Is coupled to the output transistors 12 to 14 by a current mirror, a current I _RCS proportional to a combined current obtained by adding the winding currents I _U , I _V , and I _W is passed through the current detection resistor 6. The current detection resistor 6 generates a current detection voltage according to the current, inputs the current detection voltage to the voltage difference detector 202, and feeds back the output of the voltage difference detector 202 to the comparator 1. The comparator 1 compares the input voltage with the current detection voltage and drives the output transistors 12 to 14 so that they are the same. As a result, a current corresponding to the input voltage flows through the windings 9 to 11.

As described above, according to the present embodiment, the windings 9 to 11 of the three-phase half-wave motor are sequentially energized with a conduction angle of 120 degrees to make the driving current uniform among the three-phase windings. In addition, since the current detection is performed using the current detection resistor 6 of the collector circuit of the sensor transistors 18 to 20 provided in parallel with the output transistors 12 to 14, the winding 9
The current paths of ~ 11 are windings 9 ~ 11 and output transistor 1
Since a series circuit of only 2 to 14 is used, the ratio of the voltage applied to the windings 9 to 11 to the power supply voltage can be increased, and a three-phase half-wave motor drive device that operates at a low power supply voltage can be realized.

If the power source utilization efficiency is improved as described above, the windings 9 to 9 can be driven if they are driven by the same power source voltage.
If the motor 11 can be miniaturized by making 11 small and the windings having the same resistance value are driven, the motor torque can be increased by the amount that a large current can flow.

When the current detecting resistor is provided in the current path of the winding as in the conventional example, the resistance value of the current detecting resistor is around 1Ω, but in the present embodiment, the output transistors 12 to 1 are used.
4 and the sensor transistors 18 to 20 are increased in the mirror ratio to make the current detection resistor 6 several hundred Ω.
Therefore, the resistance value can be set to several KΩ, and a current detection resistor can be built in the semiconductor integrated circuit device. Also,
In the conventional example, the external terminal of the semiconductor integrated circuit device for connecting the current detection resistor was required, but in the present embodiment, it is not necessary to particularly provide the external terminal for the current detection resistor, and one external terminal can be reduced. The semiconductor integrated circuit device incorporating the motor drive device can be downsized and external parts can be reduced.

Next, a motor drive device according to a second embodiment of the present invention will be described with reference to FIG. This embodiment is an apparatus for driving a three-phase full-wave motor.

In FIG. 2, 1 is a comparator, 2 is an energization switching circuit, 3 to 5 are Hall elements for detecting a rotating magnetic field generated by rotation of a rotor of a motor, and 6 is a current of a motor winding. A current detection resistor that causes a voltage drop, 7 is a power supply voltage terminal, 8 is a torque command input terminal, 9 to 11 are motor windings, 12 to 14 are NPN output transistors, and 15
Numerals 17 to 17 are PNP output transistors, which are output transistors for applying a drive current to the windings 9 to 11 respectively connected to the collectors. 18 to 20 are sensor transistors, and output transistors 12 to 1 are between the base and emitter.
4 base-emitters are commonly connected. Two
00 is a DC voltage generator, 201 is a speed detection device for detecting the number of rotations of the motor, and 203 is a switch for outputting or short-circuiting the output voltage of the DC voltage device according to the output of the speed detection device. . Reference numeral 202 denotes a voltage difference detector that detects a voltage difference applied across the current detection resistor.

The inverting input terminal of the comparator 1 is supplied with a set voltage corresponding to a desired current flowing from the torque command input terminal 8 to the motor winding, and the voltage drop generated by the current detecting resistor 6 is detected by the voltage difference detector. 202, and a voltage difference detector 202
Is applied to the non-inverting input terminal of the comparator 1, and the comparator 1
Amplifies the compared input voltage and outputs an error signal.

The hall elements 3 to 5 are arranged at an electrical angle of 120 degrees with respect to the rotation axis of the motor, detect the rotating magnetic field of the motor, and output a hall signal.

The energization switching circuit 2 switches the error signal for each phase of the windings 9 to 11 according to the Hall signal that detects the change in the rotating magnetic field of the motor, and outputs transistors 12 to 17.
An error signal switched at a conduction angle of 120 degrees is applied to each of the bases.

The output transistors 12 to 17 are connected to the respective windings 9 to 11 at their collectors, and are sequentially turned on at an energization angle of 120 degrees by the output signal of the energization switching circuit 2.

The sensor transistors 18 to 20 have their bases and emitters commonly connected to the bases and emitters of the output transistors 12 to 14, respectively, and have a collector current of a predetermined ratio to the collector currents of the output transistors 12 to 14. , The collectors are commonly connected, and the current detection resistor 6 is connected to the common connection point of the collectors.

The operation of the motor drive device of this embodiment constructed as described above will be described below. Further, FIG. 5 shows signal waveforms at respective points of the three-phase full-wave motor driving device constructed in FIG. This will be described with reference to FIG.

First, when a voltage corresponding to a desired current flowing through the motor winding is input from the torque command input terminal 8 to the non-inverting input terminal of the comparator 1, the comparator 1 amplifies and outputs the voltage. Next, the energization switching circuit 2 switches the output of the comparator 1 according to the Hall element signals H _U , H _V , and H _W obtained by the Hall elements 3 to 5, and outputs the driving signals U _u to the output transistors 12 to 17. _Ud , _Vu , _Vd , _Wu , and _Wd are given. And
The output transistors 12 to 17 have drive signals U _u , U _d ,
V _u, rendered conductive in response to _{V d, W u, W d} , winding 9-11 the winding currents I _U, I _V, to drive the I _W. Since the sensor transistors 18 to 20 are current-mirror coupled to the output transistors 12 to 14, a current I _RCS proportional to the windings 9 to 11 is passed through the current detection resistor 6. The current detection resistor 6 generates a current detection voltage according to the current, inputs the current detection voltage to the voltage difference detector 202, and the voltage difference detector 20
The output of 2 is fed back to the comparator 1. The comparator 1 compares the input voltage with the output of the voltage difference detector 202, which is a current detection voltage, so that the output transistors 12 to 1 are equal to each other.
Drive 7 As a result, a current corresponding to the input voltage flows through the windings 9 to 11.

When the motor reaches a predetermined number of rotations, the output of the speed detecting device 201 turns off the switch 203, and the output of the DC voltage generator 200 is added to the voltage of the current detecting resistor 6 to cause a voltage drop. The minutes increase. As a result, when the motor reaches a predetermined number of rotations, the back electromotive force generated from the motor causes the output transistors 12-1 to 12-1.
The collector voltage of the transistor 4 in the ON state and the collector voltage of the sensor transistors 18 to 20 are equivalently set to substantially the same potential. That is, by setting the collector voltages of the sensor transistors 18 to 20 and the output transistors 12 to 14 at a predetermined number of rotations of the motor to be substantially the same potential, the deviation of the current ratio due to the Early effect of the transistors is prevented and the motor is stably operated. It can be rotated.

FIG. 4 shows a DC voltage generator 200, a speed detector 201, a voltage difference detector 202, and a switch 203 in the present invention.
The configuration will be shown and the operation will be described.

At the time of starting to rotate the motor,
The desired current of the
The currents flowing through transistors 11 to 13 also increase in proportion.
Therefore, the voltage drop across the current detection resistor 6 also increases,
The back electromotive force of the motor is small. Output transistors 12-1
7 collector and sensor transistors 18-20
In order to make the rectifier potentials almost the same, the speed detection device 2
The output of 01 is input to the logic switching signal generator 204,
The output of the logic switching signal generator 204 is a switch SW. ₁The
Switch SW₂Turn on. by this,
DC voltmeter 20 composed of a differential amplifier, a resistor and a current source
No output of 0 is generated, and it is composed of a resistor and a PNP transistor.
The formed switch 203 turns on, and the differential amplifier and resistance
The voltage at point A is input to the configured differential voltage detector 202.
Is the saturation voltage of the PNP transistor from the power supply voltage terminal 7.
Is the voltage dropped.

When the number of rotations of the motor reaches a predetermined number of rotations, the desired current of the motor becomes small, and the current flowing through the sensor transistors 11 to 13 also becomes proportionally small, and the current detection resistor 6 is applied. The voltage drop also decreases and the back electromotive force of the motor increases. Output transistors 12 to 17 collector voltage and sensor transistor 1
The output of the speed detection device 201 is input to the logic switching signal generator 204, and the output of the logic switching signal generator 204 turns on the switch SW ₁ to switch the collector voltages of 8 to 20 to almost the same potential. Turn off SW ₂ . As a result, the DC voltage device 200 including the differential amplifier, the resistor, and the current source operates, the switch 203 including the resistor and the PNP transistor is turned off, and the output of the DC voltage device 200 includes the differential amplifier and the resistor. Configured differential voltage detector 20
The voltage at the point A is input to 2 and operates so as to be the output voltage of the DC voltage generator 200.

As described above, according to this embodiment, the windings 9 to 11 of the three-phase full-wave motor are sequentially energized with a conduction angle of 120 degrees, and the driving current is made uniform between the three-phase windings 9 to 11. Since the current detection is performed using the current detection resistor 6 of the collector circuit of the sensor transistors 18 to 20 provided in parallel with the output transistors 12 to 17, the current paths of the windings 9 to 11 are A series circuit consisting of only the windings 9 to 11 and the output transistors 12 to 17 can increase the ratio of the voltage applied to the windings 9 to 11 to the power supply voltage, and is a three-phase full-wave motor drive operating at a low power supply voltage. The device can be realized.

Further, by setting the collector voltages of the output transistors 12 to 17 for driving the motor and the collector voltages of the transistors 18 to 20 for sensor to substantially the same potential with respect to a predetermined number of rotations of the motor, the output transistor 12 is output. .About.17 and the transistor transistors 18 to 20 for the sensor are prevented from being deviated by the Early effect, and stable rotation accuracy of the motor can be obtained.

In this embodiment, the motor is a three-phase half-wave or full-wave motor, but it may be a multi-phase brushless motor having two or more phases. The sensor transistors 18 to 20 may be current-mirror coupled to the PNP output transistors 15 to 17. Further, all transistors may be bipolar type or MOS type.

[0042]

According to the present invention, the windings of the n-phase motor are sequentially energized, and the driving current can be made uniform among the n-phase windings.
Moreover, since the current detection resistance of the collector circuit of the sensor transistor provided in parallel with the output transistor is used for current detection, the current path of the winding is a series circuit of only the winding and the output transistor, The ratio of the voltage applied to the winding can be increased. Therefore, a large drive torque can be obtained with a low power supply voltage, and an n-phase motor drive device that smoothly rotates the motor can be realized.

Further, if the power source utilization efficiency is improved as described above, the motor can be miniaturized by thinning the windings if driven by the same power source voltage, and the windings having the same resistance value are driven. If so, the torque of the motor can be increased as much as a large current can flow.

Since the ratio of the current actually flowing through the output transistor and the current flowing through the sensor transistor at a predetermined rotation speed of the motor is prevented from being deviated by the Early effect, stable rotation accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a three-phase half-wave motor drive device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a three-phase full-wave motor drive device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a main part in the first embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional three-phase half-wave motor drive device.

FIG. 5 is a signal waveform diagram of the second embodiment of the present invention.

FIG. 6 is a signal waveform diagram of a conventional example.

[Reference Numerals] 1 comparator 2 energization switching circuit 3-5 Hall element 6 current detection resistor 7 supply voltage terminal 8 torque drive input terminal 9-11 motor windings 12 to 17 output transistors 18-20 transistor H _U, H _V , H _W Hall element signals I _U , I _V , I _W Winding current U _d , V _d , W _d (lower side) output transistor drive signal U _u , V _u , W _u (upper side) output transistor drive signal I Current flowing through _RCS current detection resistor 200 DC voltage device 201 Speed detection device 202 Voltage difference detector 203 Switch 204 Logic switching signal generator

Claims (1)

[Claims] 1. An n-phase (n is an integer of 2 or more) motor winding having one end commonly connected, n output transistors each having a collector connected to the other end of the winding, and N sensor transistors that are current-mirror coupled to the output transistor, a resistor connected to a point where the collectors of the sensor transistors are commonly connected, a DC voltmeter connected to the other end of the resistor, A switch that short-circuits the output of the DC voltage generator, a speed detection device that commands ON / OFF of the switch, a voltage difference detector that detects the voltage difference of the output of the voltage across the terminals of the resistor, and the voltage difference detector. Of the n output transistors, and a comparator that outputs an error signal by comparing the output of the n-th output transistor and the torque command signal, and switches the error signal for each phase according to the change of the rotating magnetic field of the motor magnet. Motor drive system including a power switching circuit providing the over scan.