JP2547320B2 - Overcurrent protection circuit for electronic circuit devices - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is based on abnormalities of loads such as light bulbs, solenoids, and motors used in various electronic circuit devices such as yakmono circuit devices of pachinko machines. The present invention relates to an overcurrent protection circuit which prevents the electronic circuit device from being destroyed.

[Prior art] Conventionally, in the case of a device example in which loads such as a light bulb, a solenoid, and a motor are incorporated in various electronic circuit devices such as a yakmono circuit device of a pachinko machine, these load abnormalities are generated. In some cases, the resulting overcurrent is generated, which is a major cause of device failure.

Then, conventionally, when only the load is damaged, only the load needs to be replaced, but various elements such as an integrated circuit for driving the load are often destroyed due to the occurrence of an overcurrent. In the actual situation, the electronic circuit device was normally operated by replacing and replacing the above-mentioned element with the damaged load.

[Problems to be Solved by the Present Invention]

However, in the case of using the above-mentioned conventional parts replacement and replacement means due to the abnormal state of the load, not only the load of the motor and the like but also various elements for driving the load must be replaced and replaced. There is a problem in that repairing at the time is extremely complicated and the cost of parts is high, resulting in extremely great labor and cost for maintenance.

Therefore, the present invention solves the problems of various types of electronic circuit devices such as the yakmono circuit device of the pachinko machine including various conventional loads, and overcurrent caused by the abnormal load occurs. Even so, it is an object of the present invention to provide a protection circuit in which various elements for driving a load are not destroyed.

[Means for Solving the Problems]

In the present invention, an overcurrent detection circuit for a load is provided between a signal output circuit that drives a load in an electronic circuit device and the load that operates by receiving a load drive signal output from the signal output circuit. The detected current is provided to the detection signal amplification transistor through the capacitor and the current limiting resistor, and the output signal of the transistor is fed back to the signal output circuit through the pulse width expansion circuit to load the load drive signal. Is used as a stopper signal to stop the output of.

Examples of the electronic circuit device include various kinds of circuit devices such as a yakmono circuit device of a pachinko machine containing a load such as a light bulb, a solenoid, and a motor.

[Operation of the present invention]

When a plurality of loads are driven by the load drive signal output from the signal output circuit, if one of the loads becomes abnormal, an overcurrent occurs, so the overcurrent detection circuit detects this, The overcurrent is input to the detection signal amplification transistor via the capacitor and the current limiting resistor to be amplified, and the output signal of the transistor is expanded by the pulse width expansion circuit and then fed back to the signal output circuit. The signal output circuit immediately stops the output of the load driving signal by using the fed-back signal as a stopper signal for stopping the output of the load driving signal.

Example of the present invention

Hereinafter, an embodiment of an overcurrent protection circuit for an electronic circuit device according to the present invention will be described with reference to the accompanying drawings.

In the configuration shown in FIG. 1, reference numeral 1 in the drawing is a signal output circuit, and a plurality of load drive signal output lines 2, 2 ...
・ ・ Is output. Reference numerals 3a and 3b are loads driven by the load drive signal output lines 2, 2, ..., A base current limiting resistor 4 and a load drive transistor 5, respectively.
Drive current is supplied by the. Reference numeral 6 is a resistor for detecting an overcurrent, 7 is a diode, 8 is a capacitor for preventing noise, and 9 and 10 are base current limiting resistors. Match 11
Is a transistor for increasing the detection signal, and 12 is a collector current limiting resistor of the transistor 11. Reference numeral 13 is a pulse width expansion circuit, which is composed of a resistor 14, a diode 15, and a capacitor 16. Further, reference numeral 17 in the drawing generally indicates an overcurrent protection circuit.

Although FIG. 1 attached shows only a specific example of the overcurrent protection circuit 17 for the load 3a, a similar overcurrent protection circuit 17 is also attached to the load 3b.

Hereinafter, the operation of the overcurrent protection circuit of the electronic circuit device according to the present invention having such a configuration will be described.

That is, in normal times, a drive signal is generated from the load drive signal output lines 2 and 2 of the signal output circuit 1 and applied to the base of the transistor 5 via the base current limiting resistor 4.
It drives loads 3a, 3b connected to the collectors of the transistors.

Next, the operation when an abnormality occurs in the load 3a will be described below.

That is, when the load 3a becomes inoperable due to a disconnection or the like, an overcurrent instantaneously flows to the emitter side of the transistor 5, and the overcurrent detection resistor 6 acts to prevent the overcurrent from flowing into the diode 7 for preventing backflow. The capacitor 8 is charged via this. The charged electric charge is input to the base of the detection signal amplification transistor 11 while the current is limited by the base current limiting resistors 9 and 10. Further, the output signal obtained at the collector side of the transistor 11 is added to the pulse width expansion circuit 13 composed of the resistor 14, the diode 15 and the capacitor 16 via the collector current limiting resistance 12, and the pulse width is expanded to The current detection signal output line 18 feeds back to the signal output circuit 1.

The signal output circuit 1 includes the overcurrent detection signal output line 18
The output of the load drive signal output lines 2 and 2 is stopped by using the signal obtained from That is, since the overcurrent detection signal is used as the stopper signal of the signal output circuit 1, the operation of the signal output circuit 1 is immediately stopped and the output of the drive signal to the load 3a is stopped.

 The operation for the load 3b is exactly the same as above.

Further, the loads 3a, 3b ...
Are light bulbs, solenoids, motors, etc. used for the yakmono circuit device of the pachinko machine, and can be widely applied to various kinds of electronic circuit devices for the pachinko machine for operating these loads.

[Effects of the Present Invention] By using the overcurrent protection circuit of the electronic circuit device according to the present invention described in detail above, the following effects are brought about.

That is, in the present invention, when a load incorporated in various electronic circuit devices such as a yakmono circuit device of a pachinko machine becomes abnormal, an instantaneous overcurrent caused by the abnormal condition is detected. Since the overcurrent is increased and the pulse width is extended and fed back to the signal output circuit to be the stopper signal of the load drive signal, it is possible to prevent the destruction of various elements attached to the load. Become.

Thus, according to the present invention, only the abnormal load needs to be replaced and replaced when repairing at the time of failure,
Since various elements such as other integrated circuits can be used as they are, the operation of repair is extremely simplified and at the same time the work is extremely speeded up.
Naturally, the cost required for the repair is also extremely low, and it is possible to bring about a great variety of effects such as promoting the reduction of the cost and the labor required for the maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing an embodiment of an overcurrent protection circuit for an electronic circuit device according to the present invention. Reference numeral 1 in the figure: signal output circuit 2: load drive signal output lines 3a, 3b: load 4: base current limiting resistor 5: load drive transistor 6: overcurrent detection resistor 7, 15 ... … Diodes 8 and 16 …… Capacitors 9 and 10 …… Base current limiting resistance 11 …… Detection signal amplification transistor 12 …… Collector current limiting resistance 13 …… Pulse width extension circuit 14 …… Resistance 17 …… Overcurrent protection Circuit 18: Overcurrent detection signal output line.

Claims (1)

(57) [Claims] 1. A load comprising at least one of a light bulb, a solenoid, and a motor, a load driving transistor for driving and driving the load by connecting a collector and an emitter between the load and a power source, and the load driving transistor. In a yakmono circuit of a pachinko machine including a circuit element that forms a signal for driving, and a signal output circuit that applies a load drive signal to the base of the load drive transistor based on a signal from this circuit element, An overcurrent detection circuit that can detect an overcurrent flowing between the collector and emitter of a load driving transistor, and an overcurrent detection signal detected by the overcurrent detection circuit is given through a capacitor and a current limiting resistor to amplify a detection signal. Transistor, and the pulse width of the signal amplified by the detection signal amplifying transistor to a parallel circuit of a resistor and a diode. And a pulse width expansion circuit for expanding a capacitor connected in series by a circuit connected between the power supply and ground, and stopping the output of the load drive signal from the signal whose pulse width is expanded by the pulse width expansion circuit. An overcurrent protection circuit for an electronic circuit device, characterized in that the signal is fed back to the signal output circuit as a stopper signal.