JPS60180491A - Drive device for motor - Google Patents

Abstract

PURPOSE:To obtain a speed detection pulse signal having no noise by combining electromotive force pulse signals from 2-phase drive windings and position detection pulses from two phase detectors, and operating a flip-flop formed in a ring shape with the output. CONSTITUTION:Counterelectromotive force pulse signals A, B are obtained through differential amplifiers 6, 7 from drive windings 4, 5, and input together with position detection pulse signals C, D from position detectors 2, 3 to a logic circuit 8. The circuit 8 combines the set and reset signals of a flip-flop 11. The flip-flop 11 formed in a ring shape is set or reset by the set/reset signal, thereby outputting a speed detection pulse containing no noise.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a motor drive device for a motor for rotationally driving a turntable such as a record player.

Conventional Structures and Their Problems In recent years, record players, video tape recorders, etc. have increasingly adopted direct drive motors, and there is a strong desire to reduce their costs.

A conventional two-phase motor drive circuit will be described below.

Figure 1 is a block diagram showing the circuit of a conventional back electromotive force pulse control drive motor, where 1 is the rotor, 2°3 is the rotor 1
4 and 6 are two-phase drive windings, and 6 and 7 are differential amplifiers that differentially amplify the voltages across the two-phase drive windings.
8 is a logic circuit for synthesizing speed detection pulse signals, 9 is a speed control circuit, and 10 is a drive circuit.

The operation of the conventional motor drive device configured as described above will be explained. The position detector 2.3 detects the rotational position of the rotor 1 and outputs position detection pulse signals C and D.
The drive circuit 10 causes current to flow through the two-phase drive winding 4.6 accordingly. The differential amplifier 6.7 differentially amplifies the voltage across the two-phase drive windings 4 and 5 to generate two-phase back electromotive force pulse signals A,
Make B. FIG. 2 is a time chart of the circuit.

The drive currents of the two-phase drive windings 4.6 flow avoiding the phases where the respective back electromotive voltages change sign.

Therefore, the phase in which the voltage across the drive winding 4.6 changes sign does not change depending on the magnitude of the drive current, so the back electromotive force pulse signals A and B created by differential amplification are exactly proportional to the rotation speed. It is a pulse signal with reliable edges. The logic circuit 8 synthesizes a speed detection pulse signal E from the back electromotive voltage pulse signals A and B and the position detection pulse signals C and D. The logical formula for synthesizing the speed detection pulse signal E in the logic circuit 8 is as follows. The speed control circuit 9 receives the speed detection pulse signal E.
and a reference signal to output a speed error signal. The drive circuit 10 sends a drive current according to the speed error signal to the two-phase drive windings 4 and 5, and the rotation of the rotor 1 is controlled so that the speed error signal becomes small.

However, in the above configuration, if noise is included in the voltage across the drive winding 2.3 and ringing noise is added to the back electromotive voltage pulse signal, or if noise is added to the position detection pulse signal, However, the logic circuit synthesizes an incorrect speed detection pulse signal, causing the rotor 1 to malfunction due to noise.Purpose of the InventionThe present invention solves the above-mentioned conventional problems and solves the problem of noise-induced noise. An object of the present invention is to provide a motor drive device that can accurately control the rotation of a motor without malfunctioning.

Structure of the Invention The present invention adds a ring-shaped flip-flop circuit and a set of flip-flop circuits to the above conventional structure.
By adding a logic circuit for synthesizing a reset signal, a motor drive device is realized that can accurately control the rotation speed without malfunctioning due to noise.

DESCRIPTION OF THE EMBODIMENT FIG. 3 is a block diagram of a motor drive device in an embodiment of the present invention. In FIG. 3, 1 to 7.9.10 are constructed in the same way as in FIG. 1, so their explanation will be omitted. 8 is a logic circuit for synthesizing the center/reset signals of the flip-flop circuits, and 11 is a ring-shaped flip-flop circuit for removing noise contained in the set/reset signals of the logic circuits.

The operation of an embodiment of the present invention configured as described above will be explained. The operations other than the logic circuit 8 and the flip-flop circuit are the same as those of the conventional example, so a description thereof will be omitted. The logic circuit 8 uses the back electromotive force pulse signals A and B and the position detection pulse signals C and D to set and set the Noritsubu flop circuit 11.
reset signals S1-84. ) 11 to R4 are synthesized. This is the logical formula for synthesizing the set/reset signals in the logic circuit 8. An embodiment of the logic circuit for realizing this logical formula is shown in FIG. 5 is a time chart of FIG. 4. Output signals S1 to S84 from the logic circuit 8. R1~Ra1d
It contains the noise components contained in the back electromotive force pulse signals A and B and the position detection pulses C and D as they are. This set・
Reset signals 51 to S4. By resetting the clip-flop circuit 11 configured in a ring shape with R1-R4, a speed detection pulse signal E that does not include noise components can be synthesized. Figure 6 shows the flip-flop circuit 11.
An example is shown below. Further, FIG. 7 is a time chart of the circuit of FIG. 6.

The operation of one embodiment of the Noritsubu flop circuit 11 shown in FIG. 6 will be described with reference to FIGS. 8 and 9. By setting the flip 70 knob F1 with the signal S1 and resetting it with the signal R1, a signal PF1 which is not affected by the noise of the signal s1 is obtained. Also, the flip-flop F2 is connected to the signal R
By setting it to 1 and resetting it to signal R2, a signal PF2 that is not affected by the noise of signal R1 is obtained. Furthermore, by combining the output signal PF1 of the clip-flop F1 and the output signal PF2 of the flip-flop F2, J
To obtain a phase velocity detection signal X1 that is not affected by noise of Sl and R1. Thereafter, in the same manner, phase velocity detection signals X2 to X4 that are free from the influence of noise of S2 and R2, S3 and R3, and S4 and R4 can be obtained. By synthesizing the phase velocity detection signals x1 to X4, a velocity detection pulse signal E obtained by removing the noise components of the back electromotive voltage pulse signals A and B and the position detection pulse signals C and D can be synthesized.

The speed control circuit 9 compares the speed detection pulse signal from the flop circuit 11 with the reference pulse signal and controls the drive circuit 1.
Outputs a speed error signal to 0. The drive circuit 10 sends a drive current according to the speed error signal to the two-phase drive windings 4 and 6.
The rotation of the rotor 1 is controlled so that the speed error signal becomes small.

Effects of the Invention The present invention generates set/reset signals for a flip-flop circuit by combining back electromotive voltage pulse signals from two-phase drive windings and position detection pulse signals from two position detectors using a logic circuit. This center/reset signal operates a ring-shaped flip knob circuit to synthesize a speed detection pulse signal that does not contain the noise components of the back electromotive voltage pulse signal and the position detection pulse signal, thereby preventing malfunctions due to noise. Therefore, it is possible to realize a motor drive device that does not have any disadvantages.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional motor drive device, FIG. 2 is a time chart of a part of the circuit of the conventional motor drive device, FIG. 3 is a block diagram of a motor drive device according to an embodiment of the present invention, and FIG. The figure is a circuit diagram of the logic circuit of the motor drive device of the same embodiment, FIG. 5 is a time chart of the circuit of FIG. 4, FIG. 6 is a circuit diagram of the flip-flop circuit of the motor drive device of the same embodiment, and FIG. The figure is a time chart of the circuit of FIG. 6, and FIG. 8. FIG. 9 is a block diagram and a time chart for explaining the noise removal method of the clip-flop circuit of the motor drive device of the same embodiment. 1... Rotor, 2, 3... Position detector, 4, 6... Drive winding, 6, 7... Differential amplifier, 8... ...Logic circuit, 9 ... Speed control circuit, 10 ... Motor drive circuit, 11.
...Flip-flop circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure Io Figure 2 Conduction angle Figure 3 0 44 Figure 5 Figure 6 Figure 7 Figure 8 Noise 8 minutes

Claims (3)

[Claims] (1) Two-phase drive winding, two position detectors, and the above two
A drive circuit that energizes the phase drive winding in both directions while avoiding the phase angle at which the back electromotive force changes its sign, and a drive circuit that differentially amplifies the voltage across the drive winding to generate a two-phase back electromotive voltage pulse signal. A differential amplifier, a flip-flop circuit that outputs speed detection pulses, and a set/reset signal for the flip-flop circuit is synthesized from the two-phase back electromotive voltage pulse signals and the position detection pulse signals from the two position detectors. A motor drive device characterized by comprising a logic circuit. (2) The logic circuit is a two-phase back electromotive voltage pulse signal A. Claims characterized by comprising a circuit that synthesizes pulse signals (S1 to S4.R1-R4) expressed by the following logical formula % from B and two position detection pulse signals C and D. The motor drive device according to item 1. (3) The flip-flop circuit has a flip-flop F1 which uses a pulse signal S1 synthesized by a logic circuit as a set signal and a pulse signal R1 as a reset signal, and a flip-flop F1 which uses a pulse signal R1 as a set signal and uses a pulse signal S2 as a reset signal. a flip-flop F2 that uses pulse signal S2 as a set signal and pulse signal R2 as a reset signal; an Asahi flip-flop F4 that uses pulse signal R2 as a set signal and pulse signal S3 as a reset signal; Flip-flop F6 which uses signal S3 as a set signal and pulse signal R3 as a reset signal
, pulse signal R3 is set signal, and pulse signal S4 is set as pulse signal R3.
A flip-flop F6 uses the pulse signal S4 as a set signal and uses the pulse signal R4 as a reset signal, and a flip-flop uses the pulse signal R4 as a set signal and uses the pulse signal S1 as a reset signal. F8 and the above flip-flop F1~
A first synthesis circuit that synthesizes the phase velocity detection pulse signals X1 to X4 corresponding to each phase of the pulse signals 81 to S4 from the output of F8, and compares the phase velocity detection pulse signals X1 to X4 with the phase velocity detection pulse signals. 3. The motor drive device according to claim 2, further comprising a second synthesis circuit for synthesizing speed detection pulses having a frequency four times that of the first and second speed detection pulses.