JPH10146079A - Motor control circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily control the drive of a motor with a simplified circuit structure. SOLUTION: A motor control circuit forms a flip-flop in which a power OFF transistor Q1 becomes OFF (ON) when a power ON transistor Q2 becomes ON (OFF), and also has a capacitor C1 and resistors R1 to R6 for determining the initial condition of the flip-flop. When a switch SW is turned ON and a voltage is applied to the flip-flop, a voltage is applied to the base of the transistor Q2 via current detection resistors R1, R3 to turn ON the transistor. Consequently, a power is fed to a motor M. When the motor M is driven up to the movable range and its rotation is locked, the voltage across the motor current detecting resistor R6 rises and a voltage is applied to the base of the transistor Q1 via an integral circuit consisting of resistor R4 and capacitor C1, thereby turning the transistor Q1 ON to cut off the power to the motor M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control circuit, for example, a motor control circuit for driving a door mirror, a power window and the like to open and close.

[0002]

2. Description of the Related Art Conventionally, when controlling a motor such as a door mirror or a power window, an increase in the motor current at the end of their movable range is detected, and the energization of the motor is stopped.

As this prior art, Japanese Utility Model Publication No. 4-7619 has been proposed.
No. 6 discloses a technique in which an increase in current in a locked state of a motor is detected by a positive temperature coefficient thermistor and cut in combination with a relay.

Further, Japanese Patent Application Laid-Open No. 7-255198 discloses a technique in which when a motor current exceeds a set value, energization is stopped by an electronic circuit.

[0005]

However, in the above-mentioned prior art, in Japanese Utility Model Publication No. 4-76196, when the PTC thermistor is repeatedly operated in a short period of time, the temperature of the positive temperature coefficient thermistor remains elevated and motor control is not performed. There is a problem that is impossible. In addition, since the response of the positive temperature coefficient thermistor is slow, it takes a long time to cut off the current, and it is necessary to prevent the problem of strength from occurring with respect to the motor lock torque applied to gears and the like. Get high.

Further, Japanese Patent Application Laid-Open No. 7-255198 has the disadvantage that the circuit is complicated and the number of parts is large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a motor control circuit which can be reduced in size with a simple circuit configuration having a small number of parts and can easily drive and control a motor. is there.

[0008]

SUMMARY OF THE INVENTION To solve the above problems,
In order to achieve the object, a motor control circuit according to the present invention has the following configuration. That is, an energizing means stage that starts energizing the DC motor in response to power-on, and is connected in series to the DC motor and the energizing means to convert a current applied to the DC motor into a voltage. Detecting that the DC motor has become unable to rotate, based on the voltage of the resistor and the voltage across the resistor, instructs the energizing means to stop energizing, and supplies power even after the energizing means stops energizing. Power supply stopping means for continuously instructing the stop of power supply as long as is supplied.

Preferably, the apparatus further comprises switch means for inverting the voltage applied to the DC motor and inverting the rotation direction of the DC motor, and wherein the two motor control circuits are connected to the DC motor and the switch means. One motor control circuit is connected between the DC motor and one terminal of the switch means, and the other motor control circuit is connected to the DC motor and the other terminal of the switch means so as to be symmetrically disposed. The DC motor was rotatable in either forward or reverse direction.

Also, preferably, when the applied voltage is inverted by the switch means during rotation of the DC motor, the activation of the energizing means is connected between the one control circuit and the other control circuit. Charge storage means is further provided for applying an additional voltage to the trigger voltage to ensure energization of the DC motor.

[0011] Preferably, the charge storage means includes:
One is provided for a plurality of the conducting means.

Preferably, the charge storage means includes:
Each of the plurality of conducting means is provided.

[0013] Preferably, the DC motor is a drive motor for an electric retractable door mirror in an automobile.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, as an embodiment according to the present invention, a motor control circuit for driving a drive motor forward or reverse to move an electric retractable door mirror of an automobile to a retracted position or a return position will be described. This will be described in detail with reference to the accompanying drawings.

[Basic Circuit] FIG. 1 is a basic circuit diagram of an embodiment according to the present invention.

As shown in FIG. 1, the basic motor control circuit of the present embodiment has a power-off transistor (hereinafter simply referred to as a transistor) when a power-on transistor (hereinafter simply referred to as a transistor) Q2 is on (off). A flip-flop in which Q1 is turned off (on) is configured, and has a capacitor C1 for determining an initial state of the flip-flop, and resistors R1 to R6. A DC power source B such as a battery is connected to the collector of the motor-on transistor Q2 via a switch SW, a DC motor M, and a resistor R6.
It is connected to the base of transistor Q2 via SW and resistors R1 and R3.

Further, the DC power supply B includes a switch SW and a resistor R1.
Is connected to the collector of the power-off transistor Q1 via the switch SW, the motor M, and the base of the transistor Q1 via the resistor R4.

When the switch SW is turned on and a voltage is applied to the flip-flop, a voltage is applied to the base of the transistor Q2 via the resistors R1 and R3, and the voltage is applied to the base of the transistor Q1 via the motor M and the resistor R4. Voltage is applied,
The transistor Q1 is not turned on by the capacitor C1, the transistor Q2 is turned on, and the motor M is energized. The current flowing through the current detection resistor R6 temporarily increases due to the starting current of the motor M, but the voltage applied to the base of the transistor Q1 does not exceed a predetermined level due to the operation of the integrating circuit including the resistor R4 and the capacitor C1. It has become. When the motor M is driven to the end of the movable range and its rotation is locked, the current supplied to the motor increases, the voltage across the current detection resistor R6 increases, and the integration of the resistor R4 and the capacitor C1 is performed. A voltage is applied to the base of the transistor Q1 via the circuit, and the transistor Q1 is turned on. When the transistor Q1 is turned on, the voltage applied to the base of the transistor Q2 decreases, the transistor Q2 is turned off, and the power supply to the motor M is cut off.

[First Embodiment] Next, a motor control circuit according to a first embodiment will be described.

FIG. 2 is a circuit diagram of a first embodiment according to the present invention.

As shown in FIG. 2, the motor control circuit of the first embodiment connects the two circuits shown in FIG. 1 to a switch SW so that the polarity of a power supply B is opposite, and furthermore, the motor M
Are connected so that the polarities of the connection terminals are opposite.

The forward rotation circuit (the circuit shown in the lower half of FIG. 2) of the motor M forms a flip-flop in which the power-off transistor Q11 is turned off when the power-on transistor Q12 is turned on. , A capacitor C11 that determines the initial state of the flip-flop, and resistors R12 to R1
6, and diodes D21 and D22 for preventing damage to the normal rotation side circuit when the reverse rotation side circuit is turned on, and for ensuring operation of the entire circuit.

The reverse rotation circuit of the motor M (the circuit shown in the upper half of FIG. 2) includes a flip-flop in which the power-on transistor Q22 is on (off) and the power-off transistor Q21 is off (on). A capacitor C21 that configures and determines the initial state of the flip-flop, and a resistor R22
R26, and diodes D11 and D12 for preventing the reverse side circuit from being damaged when the normal side circuit is turned on, and for ensuring the operation of the entire circuit. Also transistors
A voltage is applied to Q12 and the base of the transistor Q22 via the resistor R1 and the capacitor C1.

When the switch SW is connected to the non-inverting terminal (connected upward in FIG. 2), the DC power source B
Is connected to the collector of the motor-on transistor Q12 via the switch SW, the diode D12, the DC motor M, and the current detection resistor R16, and is connected to the base of the transistor Q12 via the diode D11 and the resistors R1, R13.

The DC power supply B is connected to the collector of the power-off transistor Q11 via the switch SW, the diode D11 and the resistor R1, and the switch SW, the diodes D12 and D
The C motor M is connected to the base of the transistor Q11 via the resistor R14.

When the switch SW is turned on to the non-inverting terminal and a voltage is applied to the flip-flop, the diode D1
1, a voltage is applied to the base of the transistor Q12 via the resistors R1 and R13, the transistor Q12 is turned on, and the motor M rotates in the normal rotation direction. In the initial state where the current temporarily increases after the switch SW is turned on, the transistor Q11
Is prevented from being turned on, the voltage applied to the base of the transistor Q11 does not exceed a predetermined level by the operation of the integrating circuit including the resistor R14 and the capacitor C11. Then, when the motor M is driven to the forward rotation movable range end and its rotation is locked, the conduction current to the motor increases, the voltage across the current detection resistor R16 increases, and the resistance from the resistor R14 and the capacitor C11 increases. A voltage is applied to the base of the transistor Q11 through the integrating circuit
Is turned on. When the transistor Q11 is turned on, the voltage applied to the base of the transistor Q12 decreases, the transistor Q12 is turned off, and the power supply to the motor M is cut off. The diodes D11 and D12 secure the base current and the collector current of the transistors Q11 and Q12, and protect the transistors Q21 and Q22 from the power supply reverse connection.

When the switch SW is turned on to the reverse terminal and a voltage is applied to the flip-flop, the diode D2
1, and a voltage is applied to the base of the transistor Q22 via the resistors R1 and R23, and the transistor Q22 is turned on, and the motor M
Rotates in the reverse direction. In the initial state where the current temporarily increases after the switch SW is turned on, the voltage applied to the base of the transistor Q21 is equal to or higher than a predetermined level by the operation of the integrating circuit consisting of the resistor R24 and the capacitor C21 so that the transistor Q21 is not turned on. It does not become. Then, when the motor M is driven to the end of the reverse rotation movable range and its rotation is locked, the conduction current to the motor increases, the voltage across the current detection resistor R26 increases, and the resistance R2
4. A voltage is applied to the base of the transistor Q21 via the integrating circuit including the capacitor C21, and the transistor Q21 is turned on. When the transistor Q21 is turned on, the voltage applied to the base of the transistor Q22 decreases, and the power supply to the motor M is cut off. The diodes D21 and D22 secure the base current and the collector current of the transistors Q21 and Q22, and protect the transistors Q11 and Q12 from the reverse connection of the power supply.

With the above circuit configuration, the forward rotation of the motor M,
By controlling the reverse rotation, the storage and return of the door mirror and the like can be realized, and at the same time, when the limit of the movable range is reached, an increase in the current to be supplied to the motor M can be detected to cut off the supply of current.

Here, the operation of the capacitor C1 will be described.

The capacitor C1 is provided so as not to cut off the supply of an excessive motor starting current generated by switching of a switch during rotation of the motor.

For example, in the case of a door mirror, if something hits the door mirror and the angle is changed, the door mirror is operated by operating the operation switch on the driver's seat to retract the door mirror and return (reverse rotation → normal rotation) to correct the door mirror to a normal position. can do. In this case, the operation is switched to the return operation during the storing operation, instead of waiting for the storing operation of the door mirror to end and returning. In this state, the rotation direction is reversed during rotation of the motor M, so that a larger current than usual flows through the motor M, and the motor current detection resistor R16 (or R
26) The voltage between both ends increases.

Therefore, the resistor R14 (or R24), the capacitor
The function of the integrating circuit composed of C11 (or C21) is insufficient, and the transistor Q11 (or Q21) turns on, and the transistor Q12
(Or Q22) is about to turn off, but the charge on capacitor C1 due to the presence of capacitor C1 keeps transistor Q12 (or Q22) on. When the motor M starts rotating, the motor current decreases, so the transistor Q1
The base voltage of 1 (or Q21) also decreases, and the motor M can continue rotating.

[Second Embodiment] Next, a motor control circuit according to a second embodiment will be described.

FIG. 3 is a circuit diagram of a second embodiment according to the present invention.

As shown in FIG. 3, the motor control circuit according to the second embodiment includes a resistor R11 between the switch SW and the diode D11 and a resistor R21 between the switch SW and the diode D21 in the circuit shown in FIG. A resistor R17 (or R27) is provided between the base of the capacitor C11 (or C21) and the transistor Q11 (or Q21), and the resistor R1 is provided between the collectors of the transistor Q12 and the transistor Q22. The setting of the overcurrent detection time can be facilitated. The resistors R16 and R26 are moved from the emitters of the transistors Q12 and Q22 to the collectors.
Is the same as Other configurations are the same as those in FIG.

[Third Embodiment] Next, a motor control circuit according to a third embodiment will be described.

FIG. 4 is a circuit diagram of a third embodiment according to the present invention.

As shown in FIG. 4, in the motor control circuit of the third embodiment, a capacitor C12 is provided at the collector of the transistor Q11 and a capacitor C22 is provided at the collector of the transistor Q21 instead of the capacitor C1 of the circuit shown in FIG. Therefore, the capacitance of the capacitor can be changed according to the magnitude of the overcurrent to the motor M. Other configurations are the same as those in FIG.

[Comparison with Japanese Unexamined Patent Publication No. 7-255198] In Japanese Unexamined Patent Publication No. 7-255198, the current completely disappears due to the first capacitor (or the second capacitor).
Is charged, and it is necessary to provide a sufficient margin for the operation time. Therefore, the first capacitor (and the second capacitor) may be increased in capacity, or the first semiconductor switching element (and the second It is necessary to use an element having a large input impedance for the second semiconductor switching element), which increases the cost.

The capacitor 29 (30) disclosed in Japanese Patent Application Laid-Open No. 7-255198 is provided for turning off the FET 22 (21) and stopping the motor when charged to a predetermined level. On the other hand, the capacitor C1 (or C12, C22) of the present embodiment increases the base voltage of the transistors Q12, Q22 against excessive motor starting current generated by switching of the switch during motor rotation, and Are provided so as not to be cut off. Therefore, the capacitor 29 (30) of JP-A-7-25519 and the capacitor C1 (or C12, C12
22) is exactly the opposite of its intended function, and its effect is quite different.

It should be noted that the present invention can be applied to modifications or alterations of the above embodiment without departing from the spirit thereof.

For example, instead of the transistors Q11, Q12, Q21 and Q22 in the above-described embodiment, another switching element such as a field effect transistor (FET) may be used.

[0043]

As described above, according to the present invention, there are provided an energizing means for starting energization of a DC motor in response to power-on, and an apparatus for converting a current supplied to the DC motor into a voltage. When detecting that the DC motor has become unable to rotate based on a resistor connected in series with the DC motor and the energizing means and a voltage across the resistor, the DC motor and the energizing means are instructed to stop energizing. By providing a power-supply stopping means that continues to instruct power-supply stop as long as the power is turned on even after power-supply is stopped, it can be easily applied to a drive motor control circuit such as an electric retractable door mirror of an automobile,
The motor control circuit can be miniaturized by a simple configuration with a small number of parts.

Further, there is further provided switching means for inverting the voltage applied to the DC motor and for inverting the rotation direction of the DC motor, and two motor control circuits are arranged symmetrically with respect to the DC motor and the switching means. As described above, one motor control circuit is connected between the DC motor and one terminal of the switch means, and the other motor control circuit is connected between the DC motor and the other terminal of the switch means. Or, by being able to rotate in either direction of reverse rotation, by applying to a drive motor such as an electric retractable door mirror of an automobile, it is possible to easily control the drive in the forward direction or the reverse direction.

[0045]

[Brief description of the drawings]

FIG. 1 is a basic motor control circuit diagram of an embodiment according to the present invention.

FIG. 2 is a motor control circuit diagram of a first embodiment according to the present invention.

FIG. 3 is a motor control circuit diagram of a second embodiment according to the present invention.

FIG. 4 is a motor control circuit diagram of a third embodiment according to the present invention.

[Explanation of symbols]

Q11, Q21: Power-off transistor Q12, Q22: Power-on transistor R12, R13, R14, R15, R16, R17: Forward circuit resistance R22, R23, R24, R25, R26, R27 ... Reverse circuit resistance C1, C11 , C21, C12, C22 ... condenser M ... DC motor

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02P 7/06 H02P 7/06 KB60J 1/17 A

Claims (6)

[Claims] An energizing means for starting energization of the DC motor in response to power-on, and a series connected to the DC motor and the energizing means for converting a current supplied to the DC motor into a voltage. When detecting that the DC motor has become unable to rotate based on the voltage between both ends of the resistor, and instructing the energizing means to stop energizing, the energizing means stops energizing. A motor control circuit comprising: an energization stop unit that continues to instruct energization stop as long as the power is turned on. 2. The motor further comprises switch means for inverting a voltage applied to the DC motor and inverting a rotation direction of the DC motor, wherein the two motor control circuits are symmetrical with respect to the DC motor and the switch means. So that one motor control circuit is connected between the DC motor and one terminal of the switch means, and the other motor control circuit is connected between the DC motor and the other terminal of the switch means. 2. The motor control circuit according to claim 1, wherein said DC motor is rotatable in either forward or reverse direction. 3. A start trigger voltage of the energizing means, which is connected between the one control circuit and the other control circuit, and is provided when the applied voltage is inverted by the switch means during rotation of the DC motor. 3. The motor control circuit according to claim 2, further comprising a charge accumulating means for applying an additional voltage to secure energization of the DC motor. 4. The motor control circuit according to claim 3, wherein one of said charge storage means is provided for a plurality of said current supply means. 5. The motor control circuit according to claim 3, wherein said charge storage means is provided for each of said plurality of current supply means. 6. The motor control circuit according to claim 2, wherein the DC motor is a drive motor for an electric retractable door mirror in an automobile.