JPS587836Y2 - Motor sudden stop circuit - Google Patents

Description

[Detailed description of the invention] The present invention relates to a circuit that quickly stops a motor drive device, such as a motor drive camera, without using a mechanical contact such as a relay, and specifically cuts off the power supply to the motor using a motor stop signal. The present invention also relates to a simple quick stop circuit that short-circuits a motor for a certain period of time and applies an electromagnetic brake, reducing standby current consumption to zero.

Conventionally, in this type of circuit, a first switching element is connected in series with the motor, and the motor is driven by conduction of this switching element, as shown in, for example, Published Utility Model Publication No. 53611/1982. When stopping the motor, the voltage change that occurs at the connection point between the switching element and the motor is detected at the moment when the switching element is turned off, and a second
A method has been proposed in which a switching element is made conductive and the motor is short-circuited and suddenly stopped for a predetermined period of time using a positive feedback circuit.

However, in this circuit, if noise enters the connection point between the switching element and the motor while the motor is being driven, the pulses generated by that noise will always short-circuit the motor for a certain period of time due to positive feedback, causing it to suddenly stop. Well, that's what happened.

An object of the present invention is to overcome the above-mentioned drawbacks and provide a quick stop circuit for a motor that has a simple configuration, consumes no standby current, and prevents malfunctions due to noise.

Embodiments adopted in the motor drive camera of the present invention will be described below based on the drawings.

In the description of each embodiment, elements common to each embodiment will be denoted by the same reference numerals and the subsequent explanation will be omitted.

1. FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

In this figure, E is a power supply, and transistor Tr1
is a transistor that controls the power supply to the motor M.

A motor control circuit 2 including a transistor Tr2 and a switch Swa alternately applies a motor drive signal and a motor stop signal to the base of the transistor Tr1.

The transistor Tr2 has its collector connected to the transistor Tr2.
1 and the emitter is connected to the positive terminal of the current E.

Transistor Tr2U becomes conductive when switch Swa is closed.

The switch Swa is, for example, a switch that is closed when the shirt release is completed and opened when the film is completed.

By closing this switch Swa, the transistor T r
When transistor Tr2 becomes conductive, the base input voltage of transistor Tr1 increases, that is, a motor drive signal is applied to the base, and transistor Tr1 becomes conductive.

Furthermore, by opening the switch Swa, the transistor T r
When transistor Tr.2 is cut off, the base input voltage of transistor Tr1 drops, that is, a motor stop signal is applied to the base, and transistor Tr.1 is also cut off.

The motor drive movement mechanism 1 is driven by the motor M by conduction of the transistor Tr1, and performs, for example, film winding and shutter charging.

Capacitor C1 is connected to power supply E via resistors R1 and R2.

The connection point between the capacitor C1 and the resistor R1 is connected to the collector of the transistor Tr□ via a backflow prevention diode D.

The base of the transistor Tr3 that detects that the capacitor C1 has been charged to a certain level is the connection point between the resistors R1 and R2, the collector is connected to the negative pole of the power supply E via the resistor R3, and the emitter is the base of the transistor Tr4 that short-circuits the motor M. It is connected to the.

Further, the connection point between the resistors R1 and R2 is connected to the collector of the transistor Tr2 via a bypass diode D2.

Here, elements C1, R□, R2゜R3yDx tD2,
Tr 3 constitutes a time constant circuit.

The emitter of the transistor Tr4 that short-circuits the motor M is connected to the positive electrode of the power source E, and the collector is connected to the connection point between the cathode of the backflow prevention diode D and the collector of the transistor Tr1.

Therefore, transistors T r 32 T r 4 are transistors Tr1 . The motor M becomes conductive due to the interruption of Tr2.
is shorted.

The capacitor C1 is charged via the transistors T r 3 and T r 4 and the resistors R1 and R2 when the transistor Tr2 is cut off.

When the voltage between the terminals of the capacitor C1 exceeds a certain value, the transistors T r 32 T r 4 are cut off.

Also, when the transistor Tr□ conducts, the capacitor C
The charge of 1 is discharged, and the capacitor CI becomes an initial state.

Next, the operation will be described.

When the transistor Tr2 becomes conductive by closing the switch Swa, a motor drive signal is applied to the base of the transistor Tr□, and the transistor Tr1/ri becomes conductive.

Therefore, electric power is supplied to the motor M, which rotates and transmits power to the motor drive interlocking mechanism.

At this time, the base potential of the transistor Tr3 is in a high state independent of the potential of the capacitor C1 due to the motor drive signal transmitted via the bypass diode D2, and both the transistors Tr3 and Tr4 are in a cutoff state.

The enclosed capacitor CF is discharged by the conduction of the transistor Tr1 and is in an initial state.

From this state, the switch Swa opens and the transistor Tr
2 is cut off, and when a motor stop signal is applied to the base of transistor Tr1, transistor T r 1 ij is cut off.

Therefore, electric power is no longer supplied to the motor M.

At this time, the base potential of the transistor Tr3 drops due to the cutoff of the transistor TrlTr2, and the transistor T
r3) Tr4 is conductive and motor M is short-circuited,
The electromagnetic brake is applied and charging of the capacitor C0 is started.

While the transistor Tr1 is cut off, the charging of the capacitor C1 continues, and when the charging voltage of the capacitor C□ reaches a certain value after a certain period of time, both the transistors Tr3 and Tr4 are no longer biased and are cut off.

Therefore, motor M is released from the short-circuited state.

However, the transistor Tr1 is in a cut-off state and the motor M remains in a stopped state.

Thereafter, the transistor Tr2 becomes conductive again by closing the switch Swa, and when the potential of the base of the transistor Tr1 rises and a motor drive signal is applied, the transistor Tr1 becomes conductive and the motor M is driven again.

At this time, the capacitor C1H is rapidly discharged via the diode D1 and the transistor Tr1 in preparation for the next stop of the motor M.

So far we have described normal operation, but below we will discuss operation when noise enters.

In this circuit, transistor Tr1. Assume that noise enters the connection point between the collector of the transistor Tr2 and the base of the transistor Tr1 when Tr2 is in a conductive state, that is, when a motor drive signal is being transmitted to the base of the transistor Tr1.

If the potential at the connection point drops due to this noise, the base potential of the transistor Tr3 drops, transistors Tr3 and Tr4/ri become conductive, and an electromagnetic brake is applied to the motor M.

However, for this circuit, the electromagnetic brake is applied only when the potential at the connection point drops due to noise, and there is no positive feedback operation, so when the noise disappears, the motor drive signal is normally applied to the base of transistor T r 1. When the voltage is applied, the transistors T r 1 and Tr 2 become conductive, and the transistors Tr 3 and Tr 4 immediately return to their original state of being cut off.

Therefore, the electromagnetic brake only takes a short time to generate noise, and does not overcome the inertia of the motor M to stop the motor operation.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the first embodiment described above, the transistor Tr3 is added and connected in Darlington to increase the current amplification factor of the transistor Tr4, but when the current amplification factor of the transistor Tr4 is sufficiently high, it is not necessary to add the transistor Tr3.

Therefore, the second embodiment is different from the first embodiment in that a diode D3 is provided instead of the transistor T r 3 for current amplification.
This is different from the example.

This diode D3 is provided between the connection point between the resistors R0 and R2 and the transistor Tr4.

Here, elements C1 and R1 constitute a time constant circuit.

The operation is the same as that in the first embodiment, so a description thereof will be omitted.

The third embodiment of the present invention shown in FIG. 3 differs from the first embodiment in that the transistor Tr3 is made conductive by the discharge current of the capacitor C2.

One end of the capacitor C2 is connected to the positive electrode of the power supply E, and the other end is connected to the collector of the transistor T r 1 via a backflow prevention diode D4.

A connection point between the capacitor C2 and the reverse current prevention diode D4 is connected to the base of the transistor T r 3 via a resistor R3.

Here, the element C2tR3 constitutes a time constant circuit.

Therefore, when transistor Tr2 is conductive, capacitor C2 is charged, and when transistor Tr2 is cut off, transistors Tr3 and Tr4 are both biased and conductive by the charging voltage of capacitor C2.

Thereafter, the charge in the capacitor C2 is discharged through the resistors R2 and R3, and when the voltage between the terminals of the capacitor C2 becomes less than a certain value, the transistors Tr3 and Tr4 are cut off.

Other operations are the same as those in the first embodiment, and will therefore be omitted.

Although the motor control circuit 2 described in the first to third embodiments is constituted by the transistor T r 2 and the switch Swa, it is obvious that it may be constituted by only the switch Swa.

Next, a specific example of the motor drive camera of the motor control circuit 2 will be explained with reference to FIGS. 4 and 5.

Shooting completion switch 5w1tI'i is a switch linked to the motor drive interlocking mechanism 1, which closes at t3 when the film exposure operation is completed and opens at t4 when the film winding is completed.

The phase switch Sw2 is a switch interlocked with the motor drive interlocking mechanism 1, which opens at t2 when the exposure operation starts and closes before the film advance is completed t4.

The release switch Sw3 is linked to the depression of a shutter button (not shown).

When the mode changeover switch Sw4 is at the S terminal, it is switched for frame photography, and when it is at the C terminal, it is switched for continuous photography.

These switch groups constitute a sequence control switching circuit 3.

Figure 5a is for single-frame shooting, that is, the mode changeover switch S
When w4 is at the S terminal, the button is pressed, and the sequence control switching circuit 3 conducts for a very short time from the shutter button press t1 to start the exposure operation it2t, and for a short period from the release of the shutter button press tx to the completion of winding 141. It shows that it is in a state.

The period between t2 and t3 varies depending on the shutter time.

Figure 5 shows the sequence control switching circuit 3 during continuous shooting, that is, when the mode changeover switch Sw4 is at the C terminal and the shutter button is pressed and the release switch Sw3 is held closed, the sequence control switching circuit 3 operates from the shutter button press t1. It shows that it is in a conductive state for a very short time at t21 when the exposure operation starts and from the time t3 when the exposure operation ends to the time t2t when the exposure operation starts.

In this case, if the shutter button is completely released and the release switch Sw is released from closing, the seedance control switching circuit 3 is released at the same timing as t4 in FIG. 5a.
(/'i non-conductive and reverse conductive.

When the sequence control switching circuit 3 is in a conductive state, the transistor Tr2 is conductive, and the transistor Tr1 is in a conductive state.
A motor drive signal is applied to the base of the motor.

When the sequence control switching circuit 3 is in a non-conducting state, the transistor Tr2 is cut off and a motor stop signal is applied to the base of the transistor Tr1.

That is, the motor is driven to advance the film from tx to t4 during frame shooting, and from t3 to t2 during continuous shooting, and the circuit described above is activated at t2 and t4 in the former case, and at t2 in the latter case. Upon activation, the motor is short-circuited and suddenly stopped.

Alternatively, a timer circuit 4 may be provided so that the motor control circuit 2 issues a motor stop signal when the sequence control switching circuit 3 is in a conductive state and the time required for normal film playback has elapsed.

The timer circuit 4 shown in FIG. 4 includes a transistor Tr5 controlled by the sequence control switching circuit 3, a capacitor C that is charged while the transistor Tr5 is conductive, a charging X of the capacitor C3, a transistor Tr6 that is conductive when the voltage reaches a certain value;
Transistor T r 6 Conductive when conductive Transistor T
It consists of a transistor Tr7 which increases the base voltage of r2 and cuts off the transistor Tr2, and a transistor TrB which rapidly discharges the capacitor C3 when the transistor Tr2 and the transistor Tr5 are cut off.

Of course, the time required for the charging voltage of the capacitor C3 to reach a certain value is set to be longer than the time required for normal film-frame playback.

If the above-mentioned timer circuit 4 is provided, it will be possible to prevent the motor from generating the torque necessary for film advance due to a drop in the power supply voltage, or when the specified number of frames of film have been wound, or due to an unexpected accident. If the sequence control switching circuit 3 remains conductive for more than a certain period of time due to film not being fed, the transistor T
r2 is cut off and the motor is short-circuited and automatically stops abruptly due to the circuit operation described above.

As detailed above, according to the present invention, after the first switching means for controlling the motor is cut off, the second switching means for short-circuiting the motor is made conductive for a predetermined period of time, so that the standby current consumption is reduced after the predetermined period of time has elapsed. In addition, when the motor control circuit issues a motor stop signal, the time constant circuit is activated, and only when the motor stop signal is maintained, the second semiconductor element detects a predetermined time depending on the time constant circuit. Since the second semiconductor element is electrically conductive, even if noise enters while the motor control circuit is emitting a motor drive signal, the second semiconductor element will not be electrically conductive for a predetermined period of time due to the timing circuit, and malfunctions due to noise can be prevented.

Moreover, its configuration is very simple. Furthermore, in the present invention, due to the circuit configuration, there is no risk that the first switching means in series with the motor and the second switching means in parallel with the motor will conduct at the same time, so in any case, a large current will flow through both switching means. You can prevent it from flowing.

Therefore, it is possible to solve the disadvantage that a large amount of power is wasted due to simultaneous conduction of both switching means.

[Brief Description of the Drawings] Fig. 1 is a circuit diagram showing a first embodiment of the present invention, Fig. 2 is a circuit diagram showing a second embodiment thereof, Fig. 3 is a circuit diagram showing a third embodiment thereof, and Fig. 4 is a circuit diagram showing a third embodiment thereof. An example of a motor control circuit that issues motor drive and stop signals, FIG. 5 is a time chart showing the conduction state of a sequence control switching circuit. [Explanation of symbols of main parts] Motor control circuit...
・2. Motor...M1 first switching means・
...Trl, second switching means...
T r 3 tTr 4 tD 3 j T r 4
, time constant circuit """CI tRl jC2JR2, 1st
Semiconductor element...D1 p D4, second semiconductor element...D2, resistor...R1, R3
, capacitor...C1, C2゜

Claims (1)

[Scope of utility model registration request] 1. a motor; a first switching means having a first control terminal and connected in series to the motor; a first switching means connected to the first control terminal and configured to generate a motor drive signal and a motor stop signal without depending on fluctuations in power supply voltage; and when a motor drive signal is transmitted to the first control terminal, the first switching means is made conductive to supply power to the motor, and when a motor stop signal is transmitted, the first switching means is cut off. a motor control circuit for stopping power supply to the motor; a second switching means having a second control terminal and connected in parallel between both terminals of the motor; and one end of the resistor that is not connected to the capacitor is connected to the second control terminal, and the second control terminal is attached so that the second switching means is conductive when the capacitor is in an initial state. When the initial state of the capacitor is released, the capacitor is charged or discharged via the resistor,
a time constant circuit that keeps the second control terminal energized for a predetermined period of time after the initial state is released; connected between a connection point between the resistor and the capacitor and a connection point between the motor and the first switching means; When the first switching means is conductive, the capacitor is set to the initial state, and when the first switching means is turned off, the capacitor is set to the initial state, and when the second switching means is conductive, the second a first semiconductor element having unidirectionality that prevents current from flowing into the capacitor via a switching means; connected between the second control terminal and the first control terminal; When the motor drive signal is being transmitted to the first control terminal, the same motor drive signal is transmitted to the second control terminal, and the second switching means is forcibly activated regardless of the energization of the second control terminal by the time constant circuit. and when the motor stop signal is being transmitted to the first control terminal, the energizing output of the time constant circuit that is applied to the second control terminal is applied to the first control terminal. 1. A motor sudden stop circuit comprising: a second semiconductor element having unidirectionality, which acts to prevent the motor from occurring. 2. Utility Model Registration For the motor sudden stop circuit according to claim 1, one end of the capacitor that is not connected to the resistor is not connected to the motor of the first switching means. When the first switching means is connected to one end of the side, the capacitor discharges through the first semiconductor element and the first switching means, and is set to an initial state, 1. A motor sudden stop circuit characterized in that when the first switching means is cut off, the second switching means is kept in a conductive state for a predetermined period of time when the charging voltage is charged through the resistor and reaches a predetermined value. 3. Utility Model Registration For the motor sudden stop circuit according to claim 1, one end of the capacitor that is not connected to the resistor is not connected to the first switching means of the motor. The capacitor is set to an initial state by being charged via the first semiconductor element when the first switching means is conductive, and the capacitor is connected to one end of the first switching means. A sudden motor stop circuit characterized in that when the circuit is cut off, the circuit is discharged through the resistor, and the second switching means is maintained in a conductive state for a predetermined period of time until the terminal voltage of the capacitor reaches a predetermined value.