JPS62166795A - Motor control circuit - Google Patents

Abstract

PURPOSE:To control a motor so that much current flows when the motor is driven at a high speed and a little current flows when the motor is driven at a low speed, by providing two circuits to limit currents flowing in control terminals of transistors. CONSTITUTION:At the Start mode time, being different from the Normal mode time, Since a transistor (Tr) 20 is rendered on to output of the base circuit G for the Start mode in place of the operation amplifier section B, the base current of the Tr 20 is large in comparison to the case that the Tr 20 is rendered on by the output of the operation amplifier B. Consequently, voltage applied to a terminal 9 in the Start mode time becomes higher than in the Normal mode time, and the motor M can start the driving at rising of higher speed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a motor control circuit, and particularly to a motor control circuit having transistors provided for controlling current flowing through each terminal of a motor.

<Prior Art> A conventional motor control circuit is provided with a circuit that controls current flowing through each terminal of a motor according to a control voltage.

An example of the IIJ control circuit for such a motor will be explained with reference to FIG.

FIG. 6 is a block diagram showing an example of such a conventional motor control circuit.

In FIG. 6, M is a motor, TR is a transistor,
R is a resistor, OP is an operational amplifier, and one of the inverting input terminals is connected to the motor M.

In the motor control circuit shown in FIG. 6, a control signal Cont is input to the non-inverting input terminal of the operational amplifier
For example, when increasing the speed of the motor M by changing the level of the control (H Co
When the level of the control signal Con t is made high and the speed of the motor M is made low, the rotation of the motor M is controlled by lowering the level of the control signal Con t .

<Problems to be Solved by the Invention> However, in the above-mentioned control circuit, it is necessary to rotate the motor M at high speed, or to increase the rotation speed within a very short period of time, and to reduce the power loss in the transistor TR. In order to achieve this, the base current of the transistor TR controlled by the operational amplifier OP can be increased, and the voltage applied to the motor M can be increased, but adopting such a configuration not only complicates the circuit, but also However, since the output current of the operational amplifier OP has its own limit, the motor M
There has been a problem in that it is difficult to increase the voltage applied to a sufficiently high voltage.

Furthermore, while using the operational amplifier OP, it is possible to increase the voltage applied to the motor M by, for example, making a Darlington connection to the transistor TR, but even with such a Darlington connection, it is difficult to make the voltage applied to the motor M sufficiently high. there were.

The present invention aims to solve the above-mentioned problems.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a motor control circuit having a transistor provided for controlling the current flowing through each terminal of the motor. The present invention is characterized in that it includes a first circuit that limits the current flowing through the device to a first value, and a second circuit that limits the current flowing to a second value that is higher than the first value.

In the above configuration, the first circuit normally limits the current flowing to the control terminal of the transistor, and when applying a high voltage to the motor, the second circuit limits the current flowing to the control terminal of the transistor. It is limited to a value greater than the value limited by the first circuit.

<Example> The present invention will be described in detail below using the drawings.

FIG. 1 is a block diagram of a motor control circuit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing details of drive circuits U, V, and W shown in FIG. 1.

In FIG. 1, U, V, and W are drive circuits that control the voltages of the motor winding U-phase terminal, V-phase terminal, and W-phase terminal, respectively. LO is drive circuit U.

This is a switching logic circuit for controlling v and W. Here, 5tart/Nor is input to the switching logic circuit LO.
The mal signal is "1" in the 5-tart mode in which the motor M is started up at high speed, and is "0" in the normal mode in which the motor M is started up normally. Hl, H2, and H3 are pulses that are output in accordance with the rotation of the motor M, and as shown in FIG. 3, the phases of Hl, H3, and H2 are advanced by 120 degrees in this order. Note that H1, H2, and H3 are pulses output by detecting the rotational state of the motor M by a detection section (not shown) that is linked to the rotation of the motor M.

In addition, "I" to "°6°' shown on the horizontal axis in Fig. 3
is a symbol indicating phase order.

Signals nUH, nW output from switching logic circuit Lo
H and nVH are drive circuits U, respectively.

This is a signal that is input manually to terminal 1 of W and This is the number for applying voltage to the corresponding terminal among the terminals and the phase II terminals.

The control signal Cont is the drive circuit U, W, respectively.
, V is a signal input manually to terminal 2 of drive circuits U and W.
, V is a signal for controlling the level of voltage applied to the motor M via the motor M.

5UHVL, 5WHVL, and 5VHWL are signals manually applied to terminals 3 of the drive circuit t, +, W, and V, respectively, and are sequentially input by °°1 when the motor M is started up at high speed in the 5tart mode.
This is the signal that rises to °'. For example, 5UHVL is 1°'
When it starts up, the power supply voltage is applied to the U-phase terminal of motor M,
(2) The phase terminal is grounded, current flows between U and 1 of motor M, and motor M rotates. Similarly, when the voltage rises to 1°, the power supply voltage is applied to the W-phase terminal of motor M, the ■-phase terminal is grounded, and a current flows between W-1 of motor M.
When 5VHWL rises to 1°, the power supply voltage is applied to the V-phase terminal, and the W-phase terminal is grounded.

5UHWL, 5WHUL, and 5VHUL are the signals that are manually applied to terminals 4 of the drive circuits U, W, and V, respectively, and are the same as described above. :1. 5UHWL is 1, similar to the signal manually input to child 3.
When 5WHUL rises to "i", power supply voltage is applied to the U+1] terminal of motor M, the W-phase terminal is grounded, current flows between U and W of motor M, and when 5WHUL rises to "i", motor M
Power supply voltage is applied to the W-phase terminal of the motor, the U-phase terminal is grounded, current flows between W-7 of the motor M, and when 5VHUL rises to "1", the power supply voltage is applied to the ■phase terminal of the motor M. U
The phase terminals are grounded and current flows between V-0 of motor M.

nUL, nWL, and nVL are drive circuits U, W, and V, respectively.
This signal is applied to the terminal 5 of the motor M, and contrary to the signal manually applied to the terminal 1 described above, when the signal reaches 1°, the corresponding terminals of the motor M are grounded. In addition, each drive circuit U, W, V is a 5 tar that performs a high-speed start-up in the forest described later.
In the t mode, the voltage applied to the motor M is increased,
In the Normal mode for normal startup, the voltage applied to the motor M is configured to be low.

Next, in the switching logic circuit Lo, H1 to 113.5
FIG. 4 shows a logical formula for outputting the above-mentioned signals from the tart/Normal signal to each drive circuit.

In Figure 4, the left column shows the switching logic LO shown in Figure 1.
Each output signal is shown, and the logical formula corresponding to the output is shown in the right column. Here, the term shown as S'' in the logical equation is the 5tart/Normal signal which is '1' in the 5tart mode for high-speed startup of the motor M and is 'o' in the Normal mode for normal startup. It shows.

Incidentally, the column indicated as DC motor in the logical formula is used to drive the DC motor when the DC motor is connected between the terminal 9 of the drive circuit V and the terminal 9 of the drive circuit W of the motor control circuit of this embodiment. This is a logical formula used for

Therefore, as shown in Fig. 4, when the DC motor is connected, if the normal mode is selected, nVH and nWL are output by the switching logic circuit L0, and if the 5tart mode is selected, 5VHWL is output by the switching logic circuit L0. Ru.

Therefore, when using a DC motor, a current is connected to the terminal (2) and the terminal W is grounded in both the 5-tart mode and the normal mode.

In addition, when a three-phase motor is connected to the drive circuits U, W, and V, a switching logic circuit is established according to the logic formula shown in FIG. 4 described above. The terminals U, W are controlled by each drive circuit U, W, V in response to a signal output from the terminals U, W, V to each drive circuit U, W, V.

Figure 5 shows the voltage of (2). In addition, the symbols "1°°" to "6" indicating the phase order shown on the horizontal axis in FIG. 5 correspond to the symbols "1"° to "6°" indicating the phase order shown in FIG. 3. , the vertical axis shows the voltage of the terminal, H is the voltage when the TL source is connected to the terminal, L is the voltage when the terminal is grounded, and the intermediate level is the voltage when the terminal is open. It shows the state in which

In other words, when driving a three-phase motor, H shown in FIG.
The voltage shown in FIG. 5 is applied to the motor M in response to the pulses of 1, H2, and H3.

Therefore, the motor M is driven and rotated in three phases by the voltages shown in FIG.

Next, the configuration of the drive circuits U, W, and V shown in FIG. 1 will be explained using FIG. 2. In addition, each drive circuit U, W
, V have exactly the same configuration. In Figure 2, 1 to 9
The terminals shown in FIG. 1 are the same as the terminals shown in FIG. 1, respectively.

In FIG. 2, A is the power supply section of the operational amplifier section B composed of Tri to Tr9, and from terminal 1 to °゛1゛'
When is input, all Tr9s to Tri are turned on. B is an operational amplifier section supplied with power by power supply section A,
The level of the control signal Cont input from the terminal 2 is compared with the voltage level applied to the manually operated motor M via the return section E, which will be described later. control.

Further, in the operational amplifier section, a current mirror circuit consisting of Tr4 and Tr5, Tr16 and T17, and Tri8 and Tri9 is provided to amplify the output current of the operational amplifier section B and take out the output current.

That is, Tri5. The PN junction area of Tri7 is Tr14. T
It is set larger than the PN junction area of r16, and current amplification is performed. R1 is a leakage prevention resistor for preventing leakage current from flowing between the base and emitter of Tr20 when the power supply from the power supply section A is cut off;
R2 is a damping resistor provided to prevent the output of the operational amplifier section B from oscillating, and E is a transition section of the operational amplifier section B, which is composed of resistors R3 and R4. The emitter of Tr20 is connected to the power supply VBATTERY, the collector is connected to the terminal 9 connected to the motor M, and the base is connected to the output of the operational amplifier section B, 5 tar.
The transistor Tr36 to which the outputs of the T-mode base circuit G are connected is a transistor whose emitter is connected to the ground, the collector is connected to the terminal 9, and the base is connected to the protection circuit H of Tr20 or The output from terminal 6 or switch circuit F is connected.

Tr20. The terminal 9 of the drive circuit is connected to the power supply VBATTERY side or grounded by the Tr36. F is the switch circuit, which is provided so that when the signal input from the terminal 5 is 1'', all of the Tr24 to Tr27 are turned on, and a current is supplied to the base of the Tr36 to turn it on.

G is the base circuit for the 5tart mode, and terminal 3
When the human input signal is “1°”, Tr32 to Tr3
5 are all turned on, "1°" is output to terminal 8, and the base current of Tr20 is drawn between the collector emitter of Tr35, turning on Tr20. Also, the signal manually input from terminal 4 is "1°". Tr2 when °゛
Tr20 is turned on by drawing the base current of Tr20 between the collector and emitter of Tr30. Note that since terminals 7 and 8 of the drive circuit are connected to terminal 6 of another drive circuit as shown in Fig. 1, the signal input from terminal 3 or 4 is
When this happens, Tr20 of the drive circuit whose terminals 3 or 4 to 1'° are manually powered is turned on, terminal 9 of the drive circuit is connected to the power supply VBATTERY, and terminal 7 of the drive circuit is connected to the power supply VBATTERY. Alternatively, the Tr 36 of the other drive circuit can be connected to the Tr 36 of the other drive circuit through another drive circuit terminal 6.
is turned on, current flows through one of the windings of the motor M, and the motor M rotates.

Incidentally, here, the Tr is
When drawing the base current of Tr20, the I transistor of the circuit G operates in the saturation region, so the base current of Tr20 can be made larger than when the base current of Tr20 is drawn by the operational amplifier section A. The voltage between the collector and emitter of the Tr20 can be reduced, and therefore a larger voltage can be applied to the motor M to start up the motor M at high speed.

H is Tr20. This is a protection circuit that prevents Tr20 etc. from being destroyed by the back electromotive force from the motor M when both Tr19 is off.
The Tr21. and a diode D1 connected between the terminal 9 and the emitter of the Tr21.

Further, D is a current mirror circuit for flowing the back electromotive current from the motor M to the ground side, and is constituted by Tr22 and Tr23.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be explained.

First, the operation in Normal mode will be explained.

In Normal mode, 5tart/Norm
a The I signal is O, and the output nUH, nV) from the switching logic circuit LO shown in FIG.

nWH becomes '°1°' according to the logical formula shown in FIG. 4, and the operational amplifier sections B of the drive circuits U, V, and W shown in FIG. I:
The base current of Tr20 of each drive circuit is supplied according to the level of the control signal Cont.
A voltage is applied to each terminal 9 of the circuit U, V, W.

On the other hand, nUL, nVL, and nWL shown in FIG. 1 become 1° in order according to the logical formula shown in FIG.
The base current of Tr38 of each drive circuit is supplied by the circuit U.

Each terminal 9 of V and W is grounded.

In this case, the relationship between the voltages at each terminal is as shown in FIG. 5 as described above, and the motor M is rotated by the voltage shown in FIG.

In addition, in this Normal mode, the Tr20 of each of the live circuits U, V, and W is driven by the output of the operational amplifier section A, so the base current of the Tr20 is not so large, and the voltage at the terminal 9 is determined by the level of the control signal Cont. is applied to motor M.

Also, as mentioned above, according to the circuit on the Kinotsu side, the operational amplifier section B of each drive circuit U, V, W is the switching logic circuit LO.
Signals nUH, nVH from.

Since power is supplied from the power supply section A according to nWH, power is supplied to the operational amplifier section B only at the necessary timing, and power is always supplied to the operational amplifier section like the one commonly used. , power consumption can be reduced compared to a conventional motor control circuit that controls the driving state of the motor by switching the output of the operational amplifier section.

Next, the operation in 5tart mode will be explained.

5tart/Normal in 5tart mode
The signal is 1'', and a signal obtained from the logical formula shown in the lower part of FIG. 4 is input from the switching logic circuit Lo to the terminals 3.4 of each drive circuit U, V, and W.

Even in such a case, the fifth
The voltage shown in the figure will be applied to each terminal manually.

Specifically, the pulses H1°H2,
As can be understood from H3, the reason why the signal 5UHWL from the switching logic circuit LO becomes °゛1'' is because Hl is °°1.
''', H2 is 'O' and H3 is 'o', that is, the phase sequence shown at 2° in the time chart shown in Fig. 3. In such a case, '2°' in Fig. 5. As shown in the phase order, the power supply voltage is applied to the U-phase terminal, and the W-phase terminal is grounded.

Also, if we look at the internal operation of each drive circuit, it is 5UHW.
When L becomes 1°, 1° is input to terminal 4 shown in FIG. is turned on, a voltage is applied to the terminal 9, and the base circuit G inputs a voltage from the terminal 7 to the terminal 6 of the drive circuit W.
is turned on, and current flows between U and W of motor M.

Next, according to the logical formula shown in Fig. 4, the fifth
The voltages shown in the figure are applied to each terminal of the motor M.

Also, as mentioned above, in the 5tart mode, No.
Unlike in rmal mode, T is generated by the output of the base circuit G for 5tart mode instead of the output of the operational amplifier section.
Since r20 is turned on, Tr20 is turned on at the output of operational amplifier section B.
The base current of the Tr20 is larger than that when the Tr20 is turned on.

Therefore, in the 5tart mode, the voltage applied to the terminal 9 is higher than in the Normal mode, and the motor M
can start driving with a faster rise.

Furthermore, in the case of a 5-tart motor, the base current of the Tr20 is small, so that the power loss between collector and emitter in the Tr20 can be reduced.

<Effects of the Invention> As described above, according to the present invention, when driving a motor at high speed with an iri 4'- circuit configuration, a large amount of current is passed through the motor, and when driving the motor at a relatively low speed, a large amount of current is passed through the motor. It is possible to control 1fftl so that a small amount of current flows through the motor.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a motor control circuit according to an embodiment of the present invention, Fig. 2 is a circuit diagram showing details of drive circuits U, V, and W shown in Fig. 1, and Fig. 3 is the same as Fig. 1. A time chart of pulses H1, H2, H3 input to the switching logic circuit L0 shown in FIG. 4, a diagram showing the logical formula of the switching logic circuit L0, and FIG. 5 showing the voltage applied to the motor M by the drive circuit. The time chart in FIG. 6 is a block diagram of a conventional motor control circuit. Lo--All switching Lothic circuit U, V, W--Drive circuit B--1 Obe amplifier section

Claims (1)

[Scope of Claims] A motor control circuit having a transistor provided to control the current flowing through each terminal of the motor, comprising: a first circuit that limits the current flowing through the control terminal of the transistor to a first value; and a second circuit that limits the value to a second value higher than the first value.