JPH073334Y2 - Motor rotation stop judgment circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a motor rotation stop determination circuit for determining whether a motor for raising and lowering a window of an automobile is rotating or stopped.

[Prior Art] FIG. 3 is a circuit showing a conventional vehicle-mounted power window lift control circuit shown in, for example, Japanese Patent Application No. 1-148271.

In the figure, 10 is, for example, a switch for raising and lowering a window,
Reference numeral 12 is, for example, a switch for lowering the window. Switches 10 and 12 are integrated switches, and are used to
It is connected to the.

16 is a resistance as a current sensor, which is a motor seen from the power supply 18.
It is connected to the downstream side of 14 and outputs an electromotive force for the current flowing in the motor 14. This electromotive output, that is, the terminal voltage of the resistor 16 is applied to each of the inverting input terminal of the comparator 20 (hereinafter referred to as “−terminal”) and the non-inverting input terminal of the comparator 22 (hereinafter referred to as “+ terminal”). . Here, the comparator 20 is provided for monitoring the upper limit of the terminal voltage, and the comparator 22
Is for monitoring the lower limit of the same terminal voltage (for determining the rotation stop of the motor)
Is provided as.

The outputs of the comparators 20 and 22 are input to the + terminal of the comparator 24. The comparator 24 turns on the transistor 26 by its output.
/ OFF control. When the transistor 26 is turned on, the solenoid 28 is excited and the ON operation of the switch 10 or 12 (connection state to the power supply 18) is maintained. The power supply to the switch holding (and releasing) circuit 30 is supplied through the power supply diode circuit 32.

In the above circuit, the comparator 22 determines whether the motor rotation is stopped.
Done by In the comparator 22, during normal operation with the switch 10 or 12 held, the terminal voltage of the resistor 16 applied to the + terminal is set higher than the reference voltage applied to the − terminal. When both the switches 10 and 12 are connected to the power source 18 side in such a state, or when the heating prevention switch (for example, bimetal) built in the motor 14 is activated, the energization line is cut off and the motor is stopped. . As a result, the input terminal potential of the comparator 22 reverses and the + terminal voltage <
-The terminal voltage is applied, and the output of the comparator 22 changes from Hi to Lo.
This Lo output discharges the electric charge of the capacitor C ₁ and lowers the + terminal voltage of the comparator 24, so that the + terminal voltage <− terminal voltage in the comparator 24. Therefore, transistor 26 is off
The solenoid 28 is de-energized and the switch 10
Or the ON operation of 12 is released.

By the way, in the lifting control circuit as described above, the load on the motor 14 is lighter when the window is lowered (opened) than when the window is lifted (closed). When the load on the motor 14 becomes lighter, the current flowing through the motor 14 decreases.

In order to cope with such a load fluctuation of the motor 14, the reference voltage applied to the-terminal of the comparator 22 is conventionally set to be smaller than the terminal voltage of the resistor 16 which is the minimum when the load is light.

[Problems to be Solved by the Invention] However, in the prior art that compares the voltage drop (terminal voltage) of the resistor 16 connected to the downstream side of the motor 14 with the reference voltage as described above, There is a problem.

First, when the resistance value of the resistor 16 is small,
The change in the current / voltage at the terminals has a characteristic that the inclination is relatively large, as indicated by A in FIG. In such a motor circuit, for example, when the load of the motor 14 decreases and the current decreases to I _{1, the} voltage applied to the + terminal of the comparator 22 becomes V _A , and the difference from the reference voltage V _R becomes small. Will end up.
Therefore, a highly accurate comparator capable of surely comparing the slight difference is required, which leads to an increase in circuit cost.

Also, the current value I ₁ becomes smaller than expected when designing the circuit,
When the + terminal voltage of the comparator 22 becomes lower than the reference voltage, the comparator 22 determines that the circuit is cut off, and the motor 14 may stop even during the window ascending / descending operation. It was

The voltage fluctuation at the + terminal of the comparator 22 also occurs due to the voltage fluctuation of the battery itself, which is the power supply 18, or the sliding load fluctuation during the window raising / lowering operation.

Next, when the resistance value of the resistor 16 is large,
The change in the current / voltage at the terminal has a characteristic that the inclination is relatively small, as indicated by B in FIG. In such a motor circuit, the voltage is V _B even when it decreases to the current I _1, and the difference from the reference voltage V _R is large, so there is no problem as described above. However, if the resistance value of the resistor 16 is large, the energy consumed by the resistor 16 is large, which is not desirable for the motor circuit.

The purpose of the present invention is to solve the above-mentioned problems of the prior art. The purpose of the present invention is to reliably judge the motor stop due to the interruption of the energization line without malfunctioning due to load fluctuation. It is an object of the present invention to provide a rotation stop determination circuit for a motor capable of performing.

[Means for Solving the Problems] In order to achieve the above object, a motor rotation stop determination circuit according to the present invention is provided on a current-carrying line to a DC motor, and a voltage of a predetermined value or more is applied in a forward direction. Until it is turned off, a diode having a resistance of off-state, a diode voltage detecting resistor connected in parallel with the diode for generating a voltage drop of the diode and outputting the voltage generated by the diode voltage detecting resistor to the diode. Includes a comparator for comparing the reference voltage set to a voltage value indicating the off resistance characteristic and determining the presence / absence of an electromotive output, and rotating or stopping the motor in response to the determination of the presence or absence of the electromotive output. It is characterized by judging.

[Operation] In the motor rotation stop determination circuit of the present invention having the above configuration, the diode having the off-resistance characteristic generates a voltage higher than the predetermined value when the motor rotates, and no current flows when the motor stops due to the interruption of the energization line. The voltage becomes 0 because it disappears. The reference voltage of the comparator is set to a value up to 0 below a predetermined voltage value at which a current starts flowing through the diode. Therefore, with respect to the reference voltage, a large voltage is always generated when the motor is rotating, and a small voltage is always generated from the diode voltage detecting resistor when the motor is stopped.
As a result, the comparator can determine the presence / absence of the electromotive output by comparing the electromotive output with the reference voltage, and determine the rotation and stop of the motor in correspondence with the presence / absence determination of the electromotive output. be able to.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing a power window lift control circuit to which a motor rotation stop detection circuit according to an embodiment of the present invention is applied. It should be noted that the same or corresponding parts as those in FIG.

In FIG. 1, reference numeral 40 denotes a diode which is a first characteristic constituent element of the present invention, and is a direct current motor (hereinafter referred to as a motor).
It is provided, for example, between the motor 14 and the resistor 16 on the energization line to the motor 14. As shown by the current / voltage characteristic C in FIG. 2, the diode 40 has an off resistance characteristic in which no current flows unless a voltage higher than V _X is applied in the forward direction.
Therefore, when the current flows and the motor 14 is rotating, the independent terminal voltage of the diode 40 is always V _X or more. Note that V _X is about several hundred mV. In addition, the characteristics A and B in FIG.
Is the same as in FIG.

Reference numeral 42 denotes a diode voltage detecting resistor (hereinafter referred to as a detecting resistor) which is the second characteristic component of the present invention, which is connected in parallel with the diode 40 and generates a voltage drop (terminal voltage) of the diode 40. Output. That is, as the voltage across the detection resistor 42, the voltage value indicated by the current / voltage characteristic C in FIG. 2 is output.

Reference numeral 44 is a comparator which is the third characteristic component of the present invention, and the terminal voltage of the diode 40 electromotively output from the detection resistor 42 is applied to its + terminal. To the-terminal of the comparator 44,
The reference voltage V _R set by the voltage dividing resistors 46 and 48 is applied. The reference voltage V _R is, as shown in FIG.
Is set to a voltage value from 0 to V _X indicating the off resistance characteristic.

The comparator 44, like the comparator 22 described in the conventional example, makes a rotation stop determination of the motor 14. That is, when the motor 14 rotates and a current flows in the energization line, a voltage of V _X or more is applied to the + terminal of the comparator 44. On the other hand, when the motor 14 stops due to the interruption of the energization line, the current becomes 0 and the + terminal voltage of the comparator 44 becomes 0. Therefore, the comparator
According to the comparison judgment of 44, there is an electromotive output of the detection resistor 42,
It is possible to determine that there is no electromotive output. As a result, the comparator 44
It is possible to determine the rotation / stop of the motor 14 in correspondence with the determination of the presence or absence of the electromotive output by.

As shown in FIG. 2, the comparison judgment as described above is performed by V _X and V _R
Since it is possible to set a relatively large difference between and, it is possible to use a comparator having a somewhat low accuracy. Therefore, the cost can be reduced.

Also, since the change in voltage is small with respect to the change in current, the energy loss does not become so large. Therefore,
Power consumption can be reduced.

Further, in the case of the present invention, the voltage applied to the + terminal does not become smaller than V _X as long as the current is flowing, that is, unless the power line is cut off. Therefore, if the reference voltage V _R is set smaller than V _{X, the} solenoid 28 will not be released due to an erroneous stop determination even if the current becomes smaller than the circuit design prediction, and the motor is unintentionally 14 will not stop.

Hereinafter, the operation of the present invention will be described while following the operation of FIG.

[1] Normal Motor Operation First, when the raising switch 10 is tilted to the side a and connected to the power supply 18, current is supplied to the motor 14. That is, the energization line is: power supply 18 → switch 10 → motor 14 → switch 12 → diode 40 (detection resistor 42) → resistor 16 → ground terminal E.

By supplying the electric current to the motor 14, the motor 14 rotates in the direction of raising the window glass. Then, the current is also supplied to the switch holding circuit 30 via the power supply diode circuit 32. The switch holding circuit 30 holds the ON operation of the switch 10.

In this case, the comparator 44, the positive terminal voltage (diode forward voltage)> - because it is the terminal voltage (the reference voltage V _R), and outputs the Hi. At this time, the comparator 20 also outputs Hi,
Capacitor C ₁ is charged, and comparator 24 has + terminal voltage>-
It becomes the terminal voltage. Therefore, the comparator 24 becomes Hi output,
As described in the related art, the ON operation of the switch 10 is retained.

[2] Motor operation under light load Even if the current flowing through the motor 14 decreases due to light load,
As indicated by C in the figure, the forward voltage of the diode 40 never becomes lower than the reference voltage V _R. Therefore, as long as the current flows through the motor 14, the comparator 44 can determine that the motor 14 is rotating, and the correct determination operation up to the low current region can be performed.

[3] Motor stop judgment due to interruption of the energization line Switch while the ON operation of switch 10 is maintained
When 12 is tilted to the a side (stop operation), no current flows in the motor 14 and the diode 40, and the diode forward voltage becomes 0. Therefore, the comparator 44
+ Terminal voltage <-terminal voltage and outputs Lo. Therefore,
The solenoid 28 is turned off, the ON operation of the switch 10 is released, and the initial state is set.

When the breaker inside the motor 14 operates, the current no longer flows through the motor 14 and the diode 40, and the ON operation of the switch 10 is released as in the above case, and the initial state is set.

[Effect of the Invention] As described above, according to the motor rotation stop determination circuit of the present invention, it is possible to determine the presence or absence of the terminal voltage of the diode electromotively output from the resistor for detecting the diode voltage.
The rotation / stop of the motor can be determined, and the reliable rotation / stop determination can be performed without being affected by the change in the motor current.

Further, since the difference between the minimum value of the diode voltage and the reference voltage can be set large, it is possible to use a comparator which is inferior in accuracy and the circuit can be constructed at low cost.

Furthermore, since the change in the voltage of the diode is small with respect to the change in the motor current, it can be seen that the resistance of the diode rapidly decreases when the current starts flowing. For this reason,
Resistance loss during normal operation of the motor can be suppressed, and energy consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a power window lift control circuit to which a motor rotation stop circuit according to an embodiment of the present invention is applied, FIG. 2 is a current / voltage characteristic diagram of a diode, and FIG. 3 is a conventional vehicle-mounted type. FIG. 4 is a circuit diagram showing a power window raising / lowering control circuit, and FIG. 4 is a current / voltage characteristic diagram in a resistor as a current sensor. 40 …… Diode 42 …… Diode Voltage detection resistor 44 …… Comparator

Claims (1)

[Scope of utility model registration request] 1. A direct current motor is provided on an energization line,
A diode that has an off-resistance characteristic until a voltage equal to or higher than a predetermined value is applied in the forward direction, a diode voltage detection resistor that is connected in parallel with this diode and that outputs the voltage drop of the diode by electromotive force, and this diode voltage detection For detecting the presence or absence of an electromotive output, including a comparator for comparing the electromotive output of the resistor for use with a reference voltage set to a voltage value at which the diode exhibits off-resistance characteristics and determining the presence or absence of the electromotive output. A rotation stop determination circuit for the motor, which determines the rotation and stop of the motor correspondingly.