JPH0241688A - Normal/reversing signal generation circuit for dc motor - Google Patents

Abstract

PURPOSE:To prevent normal and reversing transistors from performing simultaneous conduction by providing a time difference between the ending point of normal or reversing signal and the generating point of reversing or normal signal. CONSTITUTION:When a parking switch 32 is closed, a control signal is input to the base of a transistor 24. When the transistor 24 is turned ON, a transistor 22 is turned ON, and a motor 30 is rotated normally. When a brake switch 1 is closed in this state, a capacitor 3 starts being charged. Here, a transistor 5 is first turned ON. Thus, a transistor 11 is turned ON, the transistors 24, 22 are turned OFF, and the motor 30 stops rotating. After a predetermined period of time, a transistor 8 is turned ON. Thus, the transistors 12, 23 are turned ON, and the motor 30 is reversibly turned.

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention applies forward and reverse signals to a bridge-type load power supply circuit, and rotates a DC motor in the forward and reverse directions via this bridge-type load power supply circuit. This invention relates to a forward/reverse signal generation circuit for

``Prior art'' Conventional forward/reverse signal generation circuits do not create a time difference between the time point at which the forward rotation signal is generated and the time point at which the reverse rotation signal is generated. In some cases, signals are input to both the forward rotation and reverse rotation signal input terminals, and in this case, there is a problem in that the power supply is short-circuited.

FIG. 3 shows a bridge-type load power supply circuit. four) transistors T r+, which are switching elements;
Trz+ Tr, + and 'rr4 constitute a bridge circuit, and a DC power supply 1B is connected between one diagonal point of the bridge circuit. A DC motor M as a load is connected between the other diagonal points. In order to conduct the element pairs on opposite sides of the bridge, namely Trl and 1'r4 and Tr2 and T, respectively, the I-transistor Tr5. T
r6 and resistors R, , R,2 are provided.

Then, when a positive polarity signal is input to the input terminal IN, T
, 5 become conductive, and accordingly the transistor T.

and Tr4 are both conductive. As a result, motor M has
In the figure, a current flows from left to right, causing motor M to rotate forward, for example. When a signal is input to the other terminal IN2, T
When r6 becomes conductive, both TP2 and Tr3 become conductive, and the motor M rotates in reverse. However, terminal ■Nl
When signals are input to both l and lN2, l and transistor ′r
Since transistors Tr2 and 'F are conductive together, Ta, T r3 and T
A short circuit current flows through r2 and Tr4, causing these transistors to burn out.

To avoid this, it may be possible to add a switching element for circuit protection to the bridge type load feeding circuit, but
In the end, a forward/reverse signal generating circuit is required to provide an input signal, which has the drawback of making the device rather complex and expensive.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems and provide a forward/reverse signal generation circuit in which a forward rotation signal and a reverse rotation signal are not generated simultaneously.

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, a forward rotation signal and a reverse rotation signal are generated based on the presence or absence of input voltage, and the DC motor is In the forward/reverse signal generation circuit that rotates forward and reverse, there is a time constant circuit that gradually increases the output voltage from the time when the input voltage is introduced, and two circuits that are supplied based on the output voltage of this time constant circuit. By setting a potential difference between the on-levels of both switching elements,
A forward/reverse rotation signal generation circuit for a DC motor is provided, which is characterized in that a time difference is generated between the end point of the forward rotation signal or the reverse rotation signal and the generation point of the reverse rotation signal or the normal rotation signal.

According to the configuration described in "Operation" -, when one of the switching elements is turned on, a forward rotation signal or a reverse rotation signal is generated;
When the output voltage of the time constant circuit increases further after a short period of time, the other switching element turns on and a reverse rotation signal or a forward rotation signal is generated, so the forward rotation signal and the reverse rotation signal are not generated at the same time. .

"Embodiment" Next, the configuration of an embodiment of the present invention will be described with reference to FIG.

The present embodiment shown in FIG. 1 is a circuit that locks and unlocks the gear range of an automatic transmission, and includes a forward/reverse signal generation circuit A and a bridge type load power supply circuit B that is operated by the signal of this signal generation circuit A. and a DC motor M as an actuator which is rotated in forward and reverse directions by this power supply circuit B. The voltage of a power source 2 is input to the signal generating circuit A via a brake switch 1.

The signal generating circuit A includes a time constant circuit consisting of a capacitor 3 and a resistor 4. Resistors 6 and 7 are connected to both ends of the capacitor 3, and a voltage divided by the resistor 67 is supplied to the base of the transistor 5. Also,
The voltage across the capacitor 3 is divided by a resistor 9.10 and supplied to the base of the 1-herald resistor 8. The on level of transistor 5 and transistor 8 is determined by resistors 6 and 7.
By changing the voltage division ratio between resistors 9 and 10, a voltage difference is created. In this embodiment, transistor 5 is set to turn on before transistor 8. The signal generation circuit is also provided with transistors 11 and 12 for performing logic operations, and a resistor 13.
]8 is provided, and a protective diode 19.20 is provided.
is provided.

In this embodiment, the bridge-type load power supply circuit B consists of four transistors 2], 22, 23, and 24, and the base of the transistor 23 forming one input terminal is connected to the emitter base of the transistor 8 of the signal generation circuit A. transistor connected to the emitter-collector path of 2. The base of the transistor 24 serving as the other input terminal is connected to the upper end of a resistor 27 in a series circuit of a resistor 25, a diode 26, and a resistor 27. resistance 2
5 and the diode 26 is connected to the collector of the transistor 5 through the collector-emitter path of the transistor 11 in the signal generating circuit A. A DC power supply 2 is connected between one diagonal point of a bridge circuit made up of transistors 21 to 24, and a DC motor 30 is connected to a protection diode 2 between the other diagonal points of the bridge circuit.
It is connected via 829. Bias resistors 31 to 34 and a protection diode 35 are installed in the power supply circuit B (
I'm tired. In this embodiment, the changeover switch 3, which is activated by forward and reverse rotation of the DC motor 30, or the power supply circuit B
and the DC power supply 2. A parking switch 32 is connected in series to the ground sides of the signal generation circuit A and the power supply circuit B. Power is supplied from the DC power supply 2 to the signal generation circuit via the ignition switch 33.

Fuses 34 to 36 and diode 37 are for circuit protection, and lamp 38 is a brake lamp.

"Operation" The operation of this embodiment with the above configuration will be explained with reference to FIGS. 1 and 2. It is assumed that the ignition switch 33 is turned on. In the circuit shown in FIG. 1, when the parking range is selected, the parking switch 32 is closed and the power supply 2 is connected to the fuse 34. Diode 37. The selector switch 31 and the resistor 25 are in the unlocked state (in the direction of the dashed arrow). A control signal is input to the base of transistor 240 via diode 26 .

Then, as this transistor 24 becomes conductive,
Transistor 22 becomes conductive. The power supply 2 is connected to the fuse 34. Diode 37. Changeover switch 31. Transistor 22. Motor 30. Diode 28. As a result of current flowing through the transistor 24 and the ground side as shown by the solid line arrow, the motor 30 rotates in the normal direction and a locking operation is performed.
Assume that the brake switch 1 is turned on by depressing a brake pedal (not shown) in order to change the speed range. When the brake switch 1 is turned on, the fuse 36. Switch 1. An input voltage is introduced into a time constant circuit consisting of a capacitor 3 and a resistor 4 through one diode and one diode. From the moment this input voltage is introduced, the output voltage ■ across the capacitor 3 becomes the second
As shown in the figure, the voltage increases gradually, and transistor 5 becomes conductive first. When the transistor 5 becomes conductive, the base current flows from the power supply 2 to the transistor 11 through the collector-emitter path of the transistor 5, and since the transistor 11 also becomes conductive, the base current flows to the base of the transistor 24 on the power supply path B, The current flowing through the resistor 25 is absorbed into the collector-emitter path of the transistor 11 and the transistor 5 from the lower end of the resistor 25, and flows through the collector-emitter path. Therefore, the transistor 24 is turned off, and
When the transistor 24 is turned off, the base current no longer flows through the transistor 22 and the transistor 22 is also turned off, so the motor 30 stops rotating and the lock operation is turned off. After a short time Δt, the output voltage across the capacitor 3 further increases, so that the transistor 8 becomes conductive. Due to the conduction of the transistor 8, the base current of the transistor 12 flows through the collector-emitter path of the transistor 8, so that the transistor 12 becomes conductive, and the base current of the transistor 23 of the power supply circuit B flows through the collector-emitter path of the transistor 12. A base current is supplied as an unlock control signal to. That is, as shown in FIG. 2, the unlock is turned on after a time difference of Δt.

When the transistors 1 to 23 become conductive by being supplied with base current, the base current flows to the transistor 21 through the collector-emitter path of the transistor 23, and the transistor 2 also becomes conductive.

Then, a current flowing downward through the motor 30 from the emitter-collector path of the transistor 2 flows to ground via the diode 29 and the collector-emitter path of the transistor 23, so that the motor 30 is reversed, for example. The unlock operation is done, and the changeover switch 3
1 is switched to the unlock direction (the direction of the dashed arrow).

"Other Embodiments" The present invention is not limited to the details of the configuration of the above embodiments, and for example, the transistors 5 and 8 as switching elements may be replaced with field effect transistors. Furthermore, the transistors 1.1.12 that perform logic operations may be omitted in other applications. The bridge type load power supply circuit B is not limited to the configuration of this embodiment, but may have the general circuit configuration shown in FIG. 3.

"Effects" As described above, the present invention generates a forward rotation signal and a reverse rotation signal based on the presence or absence of input voltage, and rotates a DC motor in the forward and reverse directions via a bridge-type load power supply circuit. The signal generation circuit includes a time constant circuit that gradually increases the output voltage from the time when the input voltage is introduced, and two switching elements that are supplied based on the output voltage of the time constant circuit, and both of the switching elements are provided. By setting a potential difference between the ON levels of the switching elements, a time difference is created between the end point of the forward rotation signal or reverse rotation signal and the generation point of the reverse rotation signal or forward rotation signal, so the forward rotation signal and the reverse signal will not occur at the same time.
Further, it has excellent effects such as a simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a motor forward/reverse circuit using a signal generating circuit according to an embodiment of the present invention, Fig. 2 is a characteristic diagram for explaining the operation of this embodiment, and Fig. 3 is a conventional circuit diagram. FIG. 2 is a circuit diagram of a bridge type load power supply circuit for explaining a problem. 32. Capacitor, 41. Resistance, 5,8. ,. Transistor, 6, 7, 9, 10. ,,resistance.

Claims (1)

[Scope of Claims] A forward/reverse signal generation circuit that generates a forward rotation signal and a reverse rotation signal based on the presence or absence of an input voltage, and rotates a DC motor forward and reverse through a bridge-type load power supply circuit, comprising: the input voltage; It is equipped with a time constant circuit that gradually increases the output voltage from the time when voltage is introduced, and two switching elements that are supplied based on the output voltage of this time constant circuit, and a potential difference between the on-levels of these switching elements. 1. A forward/reverse rotation signal generation circuit for a DC motor, characterized in that a time difference is created between the end point of a forward rotation signal or reverse rotation signal and the generation point of a reverse rotation signal or forward rotation signal by setting .