JP2542827B2 - 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.

[Conventional technology]

Conventionally, in the case of a device example in which a load such as a light bulb, a solenoid, and a motor is incorporated in various electronic circuit devices such as a yakmono circuit device of a pachinko machine, an overcurrent due to an abnormality in these loads is generated. In some cases, it was a major cause of equipment 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 input to the input terminal of the comparator to which the reference voltage is applied via the capacitor and the current limiting resistor, and the output signal of the comparator is fed back to the signal output circuit via the pulse width expansion circuit. Is used as a stopper signal for stopping the output of the load drive signal.

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 comparator via the capacitor and the current limiting resistor. A preset reference voltage is input to the other input terminal of the comparator, and when the overcurrent voltage becomes higher than the reference voltage, the comparator outputs an output signal. The output signal 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 FIG. 1, reference numeral 1 is a signal output circuit, and this signal output circuit 1 includes a plurality of load drive signal output lines 2, 2,
A load drive signal can be output to. Reference numerals 3a, 3b, ... Are loads driven by the respective drive signals, and these loads 3a, 3b
Examples of b, ... are light bulbs, solenoids, motors, etc. used in various electronic circuit devices such as pachinko yakmono circuit devices. These loads 3a, 3b, ...
Each end is connected to the positive voltage side of the power supply (not shown),
The other ends are connected to the collectors of the transistors 5, 5, .... The bases of the transistors 5, 5, ... Are connected to the load drive signal output lines 2, 2 ,. The emitters of the transistors 5, 5, ... Are grounded via the resistors 6, 6 ,. The power supply (not shown) is grounded on the negative pressure side. Therefore, each of the transistors 5, 5, ... Is turned on when the load drive signal becomes a high voltage, and the positive voltage side of the power source (not shown), each of the loads 3a, 3b ,. The drive current flows through the resistor 6 for current detection, the ground electrode, the negative voltage side of the power supply.

Emitters of transistors 5, 5, ... and resistors for overcurrent detection
The connection points with 6, 6, ... Are connected to the anodes of the diodes 7, 7 ,. The cathodes of the diodes 7, 7, ... Are connected in common to form an OR circuit.

The cathode of each diode 7, 7, ... Is connected to the connection point between the capacitor 8 and the resistor 9. Capacitor 8 and resistor 9
The other end of is grounded. The connection point between the capacitor 8 and the resistor 9 is connected to one input terminal of the comparator 11. As a result, an overcurrent detection signal detected by at least one of the resistors 6, 6, ... For detecting overcurrent is supplied to one input terminal of the comparator 11. A reference voltage set by a series circuit of resistors 10a and 10b connected between the positive voltage side of the power source and the ground electrode is applied to the other input terminal of the comparator 11.

The output terminal of this comparator 11 is a resistor for current limiting.
It is connected via 12 to a pulse width expansion circuit 13. The pulse width expansion circuit 13 is formed by connecting a capacitor 16 in series to a parallel circuit of a resistor 14 and a diode 15 and connecting it between a power source (not shown) and ground. The anode of the diode 15 is connected to the connection point of the resistors 12 and 14, and the cathode of the diode 15 is connected to the positive voltage side of a power source (not shown). The other end of the resistor 14 is connected to the positive voltage side of a power source (not shown). The other end of the capacitor 16 is grounded. This pulse width expansion circuit 13
Output, that is, the connection point between the resistor 14 and the capacitor 16 is connected to the signal output circuit 1 via the overcurrent detection output line 18.

Although FIG. 1 attached shows only a specific example of the overcurrent detection circuit 17 for the load 3a, a similar overcurrent detection 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 immediately before the disconnection occurs.
By this action, the capacitor 8 is charged through the diode 7 for preventing the backflow of the overcurrent. That is, a pulse-like overcurrent is detected between immediately before the load 3a is disconnected and before the disconnection. The electric charge charged in the capacitor 8 is discharged by the action of the discharging resistor 9 and supplied to one input terminal of the comparator 11. The reference voltage set by the resistors 10a and 10b is input to the other input terminal of the comparator 11. The comparator 11 outputs the output signal when the voltage generated in the resistor 9 is higher than the reference voltage, and does not output the output signal when the voltage is low. This output signal is
It is supplied to the pulse width expansion circuit 13 via the resistor 12. In the pulse width expansion circuit 13, when the output signal is output, the charge accumulated in the capacitor 16 is transferred to the resistor 12 and the capacitor.
When it discharges with a time constant of 16 and the output signal is no longer output, the capacitor from the power supply changes with the time constant of resistor 14 and capacitor 16.
Discharge 16. As a result, the width of the pulsed output signal is expanded. The overcurrent detection signal output from the pulse width expansion circuit 13 is fed back to the signal output circuit 1 via the overcurrent detection signal output line 18.

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.

[Effect 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 operational 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 pulse width of this overcurrent is extended and fed back to the signal output circuit to be used as the stopper signal of the load drive signal, it is possible to prevent destruction of various elements attached to the load.

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 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 ... … Diode 8, 16 …… Capacitor 9 …… Discharge resistance 10a, 10b …… Reference voltage generation resistance 11 …… Comparator 12,14 …… Resistance 13 …… Pulse width extension circuit 17 …… Overcurrent protection circuit 18 …… … Overcurrent detection signal output line.

Claims (1)

(57) [Claims] 1. A load including at least one of a light bulb, a solenoid, and a motor, a load driving transistor for driving the load by connecting a collector and an emitter between the load and a power supply, and driving the load. And a signal output circuit for providing a load drive signal to the base of the load drive transistor based on the signal from the circuit, the yakmono circuit of the pachinko machine, An overcurrent detection circuit capable of detecting an overcurrent flowing between the collector and the emitter, and an overcurrent detection signal detected by the overcurrent detection circuit is input to one input terminal via a capacitor and a current limiting resistor, and the other input is input. Input a reference voltage to the terminal and compare the output voltage from the comparator with the comparator that compares them. And a pulse width expansion circuit for expanding the pulse width by a circuit in which a capacitor is connected in series to a parallel circuit of the card and connected between the power supply and ground, and the pulse width expansion circuit expands the pulse width. The above-mentioned signal is fed back to the signal output circuit as a stopper signal for stopping the output of the load drive signal, and an overcurrent protection circuit for an electronic circuit device is provided.