JPH0530788A - Dc motor controlling circuit - Google Patents

Abstract

PURPOSE:To control the rotational speed of DC motor without using a complicated analog component circuit. CONSTITUTION:CPU1 outputs the control instruction for the rotation control (start, stop, rotation direction and rotational speed) of DC motor 7 and a register 2 stores the instruction. An oscillator 3 generates a clock and this ckock is outputted as one-shot clock F, of which the duty is arbitrarily changed by a digital one-shot 4 under the control of the CPU1. A selector 5 selectively outputs various combinations of driver control signals G, H for supplying a bridge driver 6 with the control instruction stored in the register 2 by means of the one-shot clock F as input and the bridge driver 6 makes the rotational speed of the DC motor 7 controllable by a simple logic circuit with the use of these combinations as motor drive signals I, J for driving the DC motor 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC motor control circuit, and more particularly to a DC motor which can easily control the rotation speed of a DC motor.
The present invention relates to a motor control circuit.

[0002]

2. Description of the Related Art Conventionally, this type of DC motor control circuit is
The forward / reverse rotation direction control could be easily realized by integrating the bridge driver, but the rotation speed control was realized by controlling the voltage applied to the motor and the current flowing to the motor by an analog circuit. .

[0003]

The above-mentioned conventional DC motor control circuit has a drawback in that a complicated analog circuit is required even for simple rotation speed control.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a DC motor control circuit which can easily control the rotation speed without requiring a complicated analog circuit.

[0005]

A DC motor control circuit according to the present invention includes a CPU for controlling the entire circuit, a register for storing a plurality of control commands set by the CPU, and an oscillator for generating a clock having a constant cycle. , A digital one-shot capable of arbitrarily changing the duty of a clock generated by the oscillator to a value set by the CPU, and a duty change by the plurality of control signals stored in the register and the digital one-shot A selector for selecting and outputting the selected one-shot clock signal as a driver control signal corresponding to a desired motor rotation, a bridge driver controlled by the driver control signal selected by the selector, and the bridge .With a DC motor driven by a driver Ete constructed.

Also, the DC motor control circuit of the present invention includes a plurality of control commands set by the CPU, a rotation direction control command, a rotation speed control command, and a rotation operation control command for turning on / off the rotation operation of the CD motor. And the rotation direction according to the rotation direction control command is normal rotation and reverse rotation, and the rotation speed according to the rotation speed control command is a high speed and a low speed that can be arbitrarily set to a rotation speed lower than the high speed.・ Has a speedy structure.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

The embodiment shown in FIG. 1 is a C which controls the entire circuit.
PU1, a register 2 for storing a plurality of control commands for controlling the DC motor output by the CPU1, an oscillator 3 for outputting a clock, and a duty of a clock generated by the oscillator 3 are arbitrarily controlled under the control of the CPU1. The changeable digital one-shot 4, the control command stored in the register 2 and the output of the digital one-shot 4 are used as inputs, and a combination of these inputs is selected and output as a driver control signal corresponding to a desired motor rotation. It comprises a selector 5, a bridge driver 6 for receiving a driver control signal and outputting a motor drive signal for driving a DC motor, and a DC motor 7.

The operation of this embodiment will be described below. The control instruction A set in the register 2 by the CPU 1 is D
C motor 7 forward / reverse rotation direction motor high
Assuming that the rotation speed is low / low speed and the start / stop rotation operation of the motor, the register 2 stores them each time the CPU 1 sets them, and stores them in the rotation direction control signal B, the rotation speed control signal C, and the rotation operation. The control signal D is output. At this time, it is assumed that the rotation direction control signal B has a high level for normal rotation, the low level has a low speed, the rotation operation control signal D has a high level for start, and the low level has a stop.

On the other hand, the oscillator 3 generates a clock E having a constant cycle, and the digital one-shot 4 receiving the clock E has a cycle of the clock E determined by a control command A preset by the CPU 1 from the edge of the clock E. The one-shot clock F having a shorter one-shot pulse is output.

The selector 5 has a circuit configuration as shown in FIG. 2, and is an AND gate when the rotation direction control signal B is forward rotation, the rotation speed control signal C is high speed, and the rotation operation control signal D is start. The output of 8 becomes high level,
The driver control signal G output from the OR gate 12 becomes high level.

When the rotation direction control signal B is reverse rotation, the rotation speed control signal C is high speed, and the rotation operation control signal D is start, the output of the AND gate 9 becomes high level, which is the output of the OR gater 13. The driver control signal 14 becomes high level. Rotation direction control signal B
Is forward rotation, rotation speed control signal C is low speed, rotation operation control signal D is started, one-shot clock F
Is high level, the output of the AND gate 10 becomes high level, and the driver output from the OR gate 12 is
The control signal G becomes high level.

When the rotation direction control signal B designates reverse rotation, the rotation speed control signal C designates low speed, and the rotation operation control signal designates start, the output of the AND gate 11 becomes high level and the output of the OR gate 13 A certain driver control signal 14 goes high.

In the other combinations of the rotation direction control signal B, the rotation speed control signal C and the rotation operation control signal D, both the driver control signal G and the driver control signal H are at the low level.

The bridge driver 3 has a circuit configuration as shown in FIG. 3, and when the driver control signal G is at a high level, the switches 14 and 17 are turned on and the motor drive signal I is at the voltage level VH. , The motor drive signal J becomes the voltage level VL.

When the driver control signal H is at a high level, the switches 15 and 16 are turned on and the motor drive I is at the voltage level VL and the motor drive signal J is at the voltage level VH. Here, it is assumed that the voltage level VH is higher than the voltage level VL.

When both the driver control signal G and the driver control signal H are at the low level, the switch 14, the switch 15, the switch 16 and the switch 17 are turned off, and the motor drive signal I and the motor drive signal are output. Both J are in a high impedance state in which the voltage level is not fixed.

The DC motor 7 has a motor drive signal I
Of the motor drive signal J and the voltage level and voltage difference of the motor drive signal J and the current determined by the internal resistance value of the DC motor 7, the motor drive signal I is the voltage level VH, the motor drive signal J When the voltage level is VL, the motor / drive signal starts at forward rotation and the motor drive signal I is at voltage level V
When the L and motor drive signals J are at the voltage level VH, the motor starts in reverse rotation (as opposed to forward rotation). Also motor
It stops when both drive signal I and motor drive J are in the high impedance state.

Next, the DC motor control operation in the embodiment will be described in more detail with reference to FIGS. 4, 5, 6, and 7.

FIG. 4 shows an example of operation timing in forward rotation.

At time T1, the rotation direction control signal B is set to the normal rotation by the CPU 1. Then, time T2
In, the speed control signal C is set to high speed by the CPU 1.

At time T3, when the operation control signal D is set to start by the CPU 1, the driver control signal G becomes high level, and at this time the driver control signal H is low level, the motor
Since the drive signal I is at the voltage level VH and the motor drive signal J is at the voltage level VL, when the DC motor 7 is in the forward rotation, the rotation operation of the DC motor 7 is started at the time T4 or near the time T4. Is the motor rotation speed determined by + (indicating normal rotation) H
At S, a constant speed rotation operation is performed.

When the operation control signal D is set to stop by the CPU 1 at time T5, the driver control signal G becomes low level.
Since the control signal H is also at the low level, both the motor drive signal I and the motor drive signal J are in the high impedance state in which the voltage level is not fixed, and DC
The motor 7 is in the free state, the rotation is attenuated, and the time T6 is reached.
Stop near.

At time T7, the speed control signal C changes to CP.
Set to low speed by U1.

At time T8, when the operation control signal D is set to start by the CPU 1, the driver control signal G becomes high level. At this time, the driver control signal H is low level, so that time T9
When the one-shot clock F becomes high level in, the motor drive signal I becomes the voltage level VH,
Further, the motor drive signal J becomes the voltage level VL, and the DC motor 7 starts forward rotation to accelerate and rotate.

Thereafter, the one-shot clock F goes high.
At the level, the motor drive signal I is at the voltage level V
H, the motor drive signal J becomes the voltage level VL to drive the motor 7, and when the one-shot clock F is at the low level, the motor drive signal I, the motor drive signal J
The drive signal J becomes a high impedance state in which the voltage level is not fixed, and the operation of freeing the drive of the motor 7 is repeated.

At time T10, the DC motor 7 is rotated at a constant speed at + LS (indicating normal rotation), which is the motor rotation speed determined by the system.

At time T11, when the operation control signal D is set to stop by the CPU 1, the driver control signal G becomes low level, and at this time the driver control signal H is also low level, the motor drive signal I , Both the motor drive signal J become a high impedance state where the voltage level is not fixed,
The DC motor 7 is in a free state, its rotation is attenuated, and the DC motor 7 stops near time T12. Later, at time T13, CP
The rotation direction control signal B is set to reverse rotation by U1.

FIG. 5 shows an example of operation timing at low speed during normal rotation.

At time T14, the time of the digital one-shot 4 becomes O by the control command A from the CPU 1.
If it is set to T1 in advance, the DC motor 7 is +
It is rotating at a constant low speed of LS1.

At time T15, the time of the digital one-shot 4 becomes O by the control command A from the CPU 1.
When T2 is set, the DC motor 7 starts rotating at a low speed of LS2 later.

When the digital one-shot 4 time is set to OT3 by the control command A from the CPU 1 at time T16, the DC motor 7 will be + LS3 later.
Starts constant speed rotation at low speed.

FIG. 6 shows an example of operation timing in reverse rotation.

At time T17, the speed control signal C changes to C
Set to high speed by PU1.

When the operation control signal D is set to start by the CPU 1 at time T18, the driver control signal H becomes high level, and at this time the driver control signal G is low level, the motor
Since the drive signal I becomes the voltage level VL and the motor drive signal J becomes the voltage level VH, the DC motor 7
Starts acceleration rotation by reverse rotation.

In the vicinity of time T19, the DC motor 7 is rotated at a constant speed at a rotational speed of HS- (indicating reverse rotation), which is a motor rotational speed determined by the system.

At time T20, when the operation control signal D is set to stop by the CPU 1, the driver control signal H becomes low level, and at this time the driver control signal G is also low level, the motor
Both drive signal I and motor drive signal J are in a high impedance state where the voltage level is not fixed, and D
The C motor 7 is in the free state, the rotation is attenuated, and the time T
Stop around 21.

At time T22, the speed control signal C changes to C
Set to low speed by PU1.

When the operation control signal D is set to start by the CPU 1 at time T23, the driver control signal H becomes high level, and the driver control signal G is low level at this time.
4, when the one-shot clock F becomes high level, the motor drive signal I becomes the voltage level VL.
In addition, the motor drive signal J becomes the voltage level VH, and the DC motor 7 starts reverse rotation to accelerate and rotate.

Thereafter, the one-shot clock F goes high.
At the level, the motor drive signal I is at the voltage level V
L and the motor drive signal J become the voltage level VH to drive the motor 7, and when the one-shot clock F is at the low level, the voltage levels of the motor drive signal I and the motor drive signal J are not fixed. Yes·
The operation of entering the impedance state and freeing the motor drive is repeated.

In the vicinity of time T25, the rotating operation of the DC motor 7 becomes a constant speed rotating operation at LS (indicating reverse rotation) LS which is the motor rotating speed determined by the system.

At time T26, when the operation control signal D is set to stop by the CPU 1, the driver control signal H becomes low level, and at this time the driver control signal H is also low level, the motor drive signal I , The motor drive signal J becomes a high impedance state in which the voltage level is not fixed,
The DC motor 7 is in the free state, the rotation thereof is attenuated, and the DC motor 7 stops around time T27.

FIG. 7 shows an example of operation timing at low speed during reverse rotation.

At time T28, the time of the digital one-shot 4 is OT by the control command A from the CPU 1.
4 is preset, the DC motor 7 is -L
It is rotating at a constant low speed of S4.

At time T29, the time of the digital one shot 4 is OT5 by the control command A from the CPU 1.
Then, the DC motor 7 starts rotating at a low speed of -LS5.

Further, at time T30, when the time of the digital one-shot 4 is set to OT6 by the control command A from the CPU 1, the DC motor 7 will be -LS6 later.
Starts constant speed rotation at low speed.

As described above, the rotation of the DC motor 7 is continuously driven when the rotation speed control signal C becomes high speed and the rotation operation control signal D starts after the rotation direction is determined by the rotation direction control signal B. Then, it accelerates to a constant speed at high speed, and when the rotation operation control signal D stops, it decays and stops.

After the rotation direction is determined by the rotation direction control signal B, the rotation speed control signal C is changed to low speed,
When the rotation operation control signal D starts, the one-shot clock F drives intermittently to accelerate the
The speed becomes constant, and when the rotation operation control signal D becomes a stop, it is attenuated and stopped.

At low speed, by the intermittent drive / free time ratio of the DC motor 7 determined by the time of the digital one shot 4 set by the CPU 1,
The constant speed rotation speed of the DC motor 7 changes.

[0051]

As described above, according to the present invention, the rotation speed can be easily controlled by pulsing the voltage and current applied to the DC motor by the simple logic circuit without using a complicated analog circuit to drive the DC motor intermittently. There is an effect that can be realized.

The rotation speed control is performed by a simple firmware
By changing the duty of the clock by the hardware, it is possible to logically change from zero to a predetermined high speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a selector 5 of FIG.

3 is a block diagram showing a configuration of a bridge driver 6 of FIG.

FIG. 4 is a waveform diagram showing the timing of main signals during a forward rotation operation of the DC motor 7 of FIG.

5 is a waveform diagram showing the timing of a low speed operation of a main signal when the CD motor 7 of FIG. 1 is rotating normally.

FIG. 6 is a waveform diagram showing the timing of main signals during the reverse rotation operation of the DC motor 7 of FIG.

FIG. 7 is a waveform diagram showing the timing of low speed operation of the main signal of the reverse rotation operation of the DC motor 7 of FIG.

[Explanation of symbols]

1 CPU 2 registers 3 oscillators 4 Digital one-shot FF 5 selector 6 bridge driver 7 DC motor 8-11 AND gate 12,13 OR gate 14-17 switch

Claims (2)

[Claims] 1. A CPU for controlling the entire circuit and the CP
A register for storing a plurality of control instructions set by U, an oscillator for generating a clock of a constant cycle, and a digital one capable of arbitrarily changing the duty of the clock generated by the oscillator to a value set by the CPU. Selector for selecting and outputting a shot, the plurality of control signals stored in the register, and the one-shot clock signal whose duty is changed by the digital one-shot as a driver control signal corresponding to a desired motor rotation. And a bridge driver controlled by a driver control signal selected by the selector, and a DC motor driven by the bridge driver.
C motor control circuit. 2. A plurality of control commands set by the CPU are a rotation direction control command of the DC motor, a rotation speed control command, and a rotation operation control command for turning on / off the rotation operation, and the rotation is performed. The rotation direction by the direction control command is forward rotation and reverse rotation, and the rotation speed by the rotation speed control command is high speed and low speed that can be arbitrarily set to a rotation speed lower than the high speed. The DC motor control circuit according to claim 1.