JP2007143211A - Switching power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switching power supply in which an element can be protected against overvoltage and the switching power supply can be protected against breakage due to input of an overvoltage. <P>SOLUTION: A switching power supply comprising a circuit for rectifying an inputted AC voltage into a DC voltage, a first circuit for smoothing a DC voltage to supply it through a first smoothing element to a first load with higher need for protection, and a second circuit for smoothing a DC voltage to supply it through a second smoothing element to a second load with lower need for protection than the first load is further provided with a circuit for switching such that a voltage is not supplied at least to the first and second smoothing elements when the overvoltage is input. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a switching power supply that is used in a gaming machine such as a pachinko machine or a pachislot machine and converts an AC voltage into a DC voltage.

  Conventionally, AC24V is used as an input power source in gaming machines such as pachinko machines and pachislot machines. The AC 24V power source is provided by converting AC 100V, which is a commercial power source, by a transformer provided in the game hall. In the gaming machine, a switching power supply that converts the AC 24V input power into DC 12V or DC 5V used in the gaming machine is used.

In recent years, liquid crystals and accessories provided in gaming machines tend to increase in size. For this reason, there is an increasing demand for a large capacity switching power supply.
In addition, the gaming machine needs to hold operations such as a CPU for determining whether or not a big hit or a sensor serving as a payout trigger so that information such as a big win is not erased during a power failure or the like.
The holding time for holding this operation is generally generated by an input full-wave rectifying and smoothing capacitor. When the switching power supply becomes high power, it is necessary to increase the size of the full-wave rectifying and smoothing capacitor in order to ensure a sufficient holding time.

  In such a background, there is a power supply for a gaming machine that separates a circuit into an output that requires a holding time and an output that does not need a holding time, and for the circuit that does not need a holding time, a power supply for a gaming machine that stops the load at the time of a power failure. It has been proposed (see Patent Document 1). It is said that the capacity of the full-wave rectifying and smoothing capacitor can be reduced by the power supply for gaming machines.

  On the other hand, in facilities where gaming machines are installed, such as game halls, in addition to AC24V power source converted by a transformer, AC100V power source used for devices such as ball lending machines is mixed. For this reason, there is a possibility that the switching power supply to be connected to the AC 24V power supply is erroneously connected to the AC 100V power supply.

  In order to reduce the size and efficiency of an AC 24V switching power supply, it is desirable to use components with a breakdown voltage of about 50V for internal capacitors and semiconductors. However, if AC100V, which is an overvoltage, is erroneously applied to these components, the element is destroyed, that is, the switching power supply is destroyed.

  Such destruction of the switching power supply due to overvoltage can be avoided if sufficient care is taken when connecting the power supply. However, installation and replacement work of gaming machines are often executed simultaneously for a large number of gaming machines. For this reason, it is necessary to help not only a skilled person but also an unfamiliar person, and there are cases where it is not possible to thoroughly prevent connection errors.

Here, when the switching power supply is designed to withstand the application of AC 100V, it is conceivable that the switching power supply is composed of components having a breakdown voltage of around 150V.
However, if all the parts can withstand the application of AC 100V in this way, there is a problem that the switching power supply becomes large, loss increases, and costs increase.
And the power supply for gaming machines described above cannot cope with such problems.

Japanese Patent Laid-Open No. 2003-154079

  In view of the above problems, an object of the present invention is to propose a switching power supply capable of protecting an element from an overvoltage, and to prevent destruction of the switching power supply due to an input of an overvoltage.

The present invention includes a rectifier circuit that rectifies an input AC voltage into a DC voltage, a first circuit that supplies a DC voltage that is smoothed by a first smoothing element to a first load that is highly necessary to be protected,
A switching power supply comprising a second circuit for smoothing and supplying a DC voltage to a second load having a lower need for protection than the first load by a second smoothing element, and the input voltage is an overvoltage In some cases, the switching power supply includes a switching circuit that switches at least not to supply a voltage to the first smoothing element and the second smoothing element.
Thereby, at least the first smoothing element and the second smoothing element can be protected from overvoltage, and the destruction of the switching power supply due to the input of the overvoltage can be prevented.

  As an aspect of the present invention, voltage supply stability that prevents voltage supply from the first smoothing element that supplies a smoothing voltage to the first load to a load other than the first load when an input voltage is interrupted. A circuit can be provided.

  Thereby, when the input voltage is suddenly cut off due to a power failure or the like, the voltage supply to the first load can be continued for a certain time. Therefore, it is possible to complete an operation (for example, a backup operation) required until the voltage supply to the first load is cut off during the voltage supply from the first smoothing element.

In addition, as an aspect of the present invention, it is possible to provide a timer circuit that prevents voltage from being supplied to the first smoothing element and the second smoothing element until a predetermined time has elapsed.
Accordingly, when an overvoltage is input, it is possible to prevent the overvoltage from being input to the first smoothing element and the second smoothing element at the moment of input, and it is possible to more reliably perform protection from the overvoltage.

As an aspect of the present invention, the timer circuit can be disposed in the second circuit.
Thus, when the voltage is supplied from the first smoothing element to the first load when the power is cut off, the first smoothing element does not supply a voltage to the timer circuit, and the voltage can be stably supplied to the first load. it can. Therefore, the capacity design of the first smoothing element can be easily performed.

  We propose a switching power supply that can protect the device from overvoltage and prevent destruction of the switching power supply caused by overvoltage input.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a circuit diagram of a switching power supply 1 provided in a gaming machine such as a pachinko machine or a pachislot machine.

  The switching power supply 1 is connected to, for example, an AC 24V AC power supply 101 and operates. The AC 24V AC voltage is supplied by converting a commercial power supply of AC 100V by an appropriate transformer provided in a game hall or the like.

  The switching power supply 1 includes a first power supply circuit 2 of a first system that supplies a DC voltage of, for example, DC 5 V to the first load circuit 20, and a DC power of, for example, DC 12 V, for example, after the branch sections 102 and 103 provided in the vicinity of the AC power supply 101 A second power supply circuit 3 of a second system for supplying a voltage to the second load circuit 30 is provided.

  The first load circuit 20 is a circuit to which a load such as a CPU or a sensor that needs to hold a voltage is connected so that information such as a jackpot is not erased due to a sudden power interruption.

  The second load circuit 30 is a circuit to which a load such as an LED for lighting or an audio output unit that does not have much influence even if there is a sudden voltage interruption and does not need to hold a voltage is connected.

  It should be noted that the load that does not need to hold the voltage connected to the second load circuit 30 is not only a load that does not need to hold the voltage completely, but also a load that holds the voltage is preferable but may not hold it. included.

  In this embodiment, the smoothing capacitor 203 holds the voltage of the first load circuit 20 for a fixed time, and the smoothing capacitor 303 holds the voltage of the second load circuit 30 for a fixed time. The fixed time for holding the voltage is appropriately designed to improve efficiency so that the fixed time for holding the voltage by the smoothing capacitor 203 is different from the fixed time for holding the voltage by the smoothing capacitor 303. However, it may be set to the same time. Is possible.

  The first power supply circuit 2 is a series circuit mainly composed of a diode bridge 201, a smoothing capacitor 203 that is an electrolytic capacitor, and a MOSFET 141. The first power supply circuit 2 is determined as an overvoltage and a determination circuit 110 that determines whether or not an overvoltage occurs. In this case, a short circuit 120 for short-circuiting (bypassing) the gate voltage of the MOSFET 141 is connected. The first power supply circuit 2 is a circuit for supplying a smoothed DC voltage to the first load circuit 20.

  Connection of each element in the first power supply circuit 2 is as follows. The branch parts 102 and 103 connected to the AC power source 101 are connected to a diode bridge 201 that performs full-wave rectification of the input voltage. The positive electrode of the diode bridge 201 is connected to the positive electrode of the smoothing capacitor 203 that smoothes the voltage input to the first load circuit 20. The negative electrode of the smoothing capacitor 203 is connected to the drain of the MOSFET 141 having an ON / OFF switching function of voltage supply to the smoothing capacitor 203. The source of the MOSFET 141 is connected to the negative electrode of the diode bridge 201 and the short circuit 120 provided in the subsequent stage of the determination circuit 110. The gate of the MOSFET 141 is connected to an integration circuit 130 having a timer function that causes the MOSFET 141 to be in a closed state after a predetermined time has elapsed from the voltage supply from the AC power supply 101.

  The second power supply circuit 3 is a series circuit mainly composed of a diode bridge 301, a smoothing capacitor 303 that is an electrolytic capacitor, and a MOSFET 141. The second power supply circuit 3 outputs the output voltages of the determination circuit 110, the short circuit 120, and the diode bridges 201 and 301. An integrating circuit 130 for dividing the voltage and charging the gate of the MOSFET 141 is connected. The second power supply circuit 3 is a circuit for supplying a smoothed DC voltage to the second load circuit 30.

  Connection of each element in the second power supply circuit 3 is as follows. The branch parts 102 and 103 connected to the AC power supply 101 are connected to a diode bridge 301 that performs full-wave rectification of the input voltage. The positive electrode of the diode bridge 301 is connected to the positive electrode of a smoothing capacitor 303 that smoothes the voltage input to the second load circuit 30. The negative electrode of the smoothing capacitor 303 is connected to the drain of the MOSFET 141 having an ON / OFF switching function for supplying a voltage to the smoothing capacitor 303. The source of the MOSFET 141 is connected to the negative electrode of the diode bridge 301 and the short circuit 120 provided at the subsequent stage of the determination circuit. The gate of the MOSFET 141 is connected to an integration circuit 130 having a timer function that causes the MOSFET 141 to be in a closed state after a predetermined time has elapsed from the voltage supply from the AC power supply 101.

  The determination circuit 110 includes diodes 202 and 302 and a Zener diode 111 that is a determination element. The diode 202 has an anode connected to the positive electrode of the diode bridge 201 and a cathode connected to the cathode of the Zener diode 111. The diode 302 has an anode connected to the positive electrode of the diode bridge 301 and a cathode connected to the cathode of the Zener diode 111. The anode of the Zener diode 111 is connected to the short circuit 120. It is preferable to use a Zener diode 111 having a slightly higher Zener voltage than a value obtained by multiplying the maximum value of a regular AC input voltage (for example, AC 24 V) by √2.

  The short circuit 120 includes resistors 122 and 123, a capacitor 121, and a transistor 125. The resistors 122 and 123 are connected in series, the front end of the resistor 122 is connected to the anode of the Zener diode 111, and the rear end of the resistor 123 is connected to the negative electrodes of the diode bridges 201 and 301 and the MOSFET 141. Connected to the source. The positive electrode of the capacitor 121 is connected to the anode of the Zener diode 111 and the end portion on the front stage side of the resistor 122. The negative electrode of the capacitor 121 is connected to the negative electrodes of the diode bridges 201 and 301 and the source of the MOSFET 141. The transistor 125 has a base connected between the resistors 122 and 123, a collector connected to the integrating circuit 130, and an emitter connected to the negative electrodes of the diode bridges 201 and 301 and the source of the MOSFET 141.

  The integrating circuit 130 includes resistors 131 and 132 and a capacitor 133. The resistor 131 and the resistor 132 are connected in series to form a voltage dividing circuit. The front end of the resistor 131 is connected to the positive electrode of the diode bridge 301, and the rear end of the resistor 132 is a diode. The negative electrodes of the bridges 201 and 301 and the source of the MOSFET 141 are connected. Between the resistor 131 and the resistor 132, the collector of the transistor 125, the positive electrode of the capacitor 133, and the gate of the MOSFET 141 are connected. The negative electrode of the capacitor 133 is connected to the negative electrodes of the diode bridges 201 and 301 and the source of the MOSFET 141.

  With the above configuration, the AC voltage supplied from the AC power supply 101 is branched by the branching units 102 and 103, the DC voltage smoothed through the first power supply circuit 2 is supplied to the first load circuit 20, and the second power supply circuit 3. The smoothed DC voltage can be supplied to the second load circuit 30.

Next, the operation of the circuit will be described.
First, when a regular input voltage (for example, AC 24 V) is input from the AC power supply 101, the current i1 flows through the integration circuit 130 as shown in the circuit diagram of FIG. Specifically, the current i1 flows through the AC power source 101, the branch unit 102, the diode bridge 301, the resistor 131, the capacitor 133, the branch unit 103, and the AC power source 101 in this order. As a result, the capacitor 133 between the gate and the source of the MOSFET 141 in the open circuit state is charged.

  When a predetermined time (for example, 40 ms to 80 ms) elapses and the capacitor 133 between the gate and source of the MOSFET 141 is charged, the MOSFET 141 is closed, and as shown in FIG. Currents i2 and i3 flow between them. At this time, the Zener diode 111 serving as a determination element in the determination circuit 110 does not pass a current because the input voltage is smaller than a preset voltage (for example, 50 V).

  The current i2 flows from the AC power source 101 through the branching unit 102, the diode bridge 201, the smoothing capacitor 203, the MOSFET 141, the diode bridge 201, and the branching unit 103 in this order. Thereby, the smoothing capacitor 203 is charged.

  The current i3 flows from the AC power source 101 through the branching unit 102, the diode bridge 301, the smoothing capacitor 303, the MOSFET 141, the diode bridge 301, and the branching unit 103 in this order. As a result, the smoothing capacitor 303 is charged.

Next, the flow of the current i5 when an overvoltage (for example, AC 100V) is input will be described with the circuit diagram shown in FIG.
When an overvoltage is input from the AC power supply 101, as indicated by a current i5, the branching section 102, the diode bridge 301, the diode 302, the Zener diode 111, the short circuit 120, and the branching section 103 are arranged in this order from the AC power supply 101. Current flows. Although this example describes the case where the smoothing capacitor 303 detects an overvoltage, the smoothing capacitor 203 may detect the overvoltage depending on the phase. In such a case, the current i5 flows through the diode bridge 301, the diode 202, and the Zener diode 111 in this order after the branch unit 102, and the other flows are the same as when the above-described smoothing capacitor 303 detects an overvoltage. It becomes a flow.

  When the current i5 flows in this way, the short circuit 120 is activated, the capacitor 133 having the timer function is not charged, the MOSFET 141 is opened, the currents i2 and i3 shown in FIG. The electrolytic capacitor will not be charged.

  In addition, once an overvoltage is input, even if a moment when the determination circuit 110 does not operate due to the phase relationship of the input voltage occurs, the current i6 continues to flow through the short circuit 120 due to the supply of voltage from the capacitor 121. This current i6 flows from the positive electrode of the capacitor 121 to the resistor 122, the base of the transistor 125, the emitter of the transistor 125, and the negative electrode of the capacitor 121. Thereby, the short circuit 120 by the transistor 125 continues to operate, so that the circuit is stably operated.

  With the above operation, when one of the diode bridges 201 and 301 is in an overvoltage state, the capacitor 133 is not charged by the determination circuit 110 and the short circuit 120, the MOSFET 141 is opened, and the smoothing capacitors 203, 303, An overvoltage is not applied to the integrating circuit 130, the first load circuit 20, and the second load circuit 30, and these can be protected from the overvoltage, and the switching power supply 1 can be prevented from being destroyed.

  Therefore, it is not necessary to configure all the elements constituting the switching power supply 1 with elements that can withstand overvoltage, and the switching power supply 1 can be reduced in size, reduced in loss, and reduced in cost.

  Further, since the diodes 202 and 302 are provided, the smoothing capacitors 203 and 303, the integration circuit 130, the first load circuit 20 and the second load circuit 30 are protected from overvoltage even when the phase is shifted. And the destruction of the switching power supply 1 can be prevented.

  Further, since the MOSFET 141 is used, loss can be reduced when a regular voltage is input, and the switching power supply 1 can be made more efficient than using a thyristor.

  Further, when the power supply is suddenly cut off due to a power failure or the like, the smoothing capacitor 203 can supply a voltage to the first load circuit 20 to hold the voltage.

  In particular, when the power is cut off and the voltage is supplied from the smoothing capacitor 203, it is possible to prevent the voltage from being supplied to the second power supply circuit 3 due to the presence of the diode 302 and the Zener diode 111. Backflow can be prevented.

  As a result, the voltage charged by the smoothing capacitor 203 can be supplied only to the first load circuit 20, and a load that needs to hold a voltage, such as a CPU, is provided, and holding the voltage for a certain time is very important. A holding time for supplying a voltage from the smoothing capacitor 203 to the load circuit 20 after the power is cut off can be ensured accurately for a certain time.

  Therefore, it is possible to easily and accurately perform circuit design based on the holding time that requires the holding voltage to be supplied to the first load circuit 20. As the holding time, a time including a backup time for performing the backup can be set.

  In addition, by not supplying voltage from the smoothing capacitor 203 to the elements that do not need to hold voltage when the power is turned off in this way, the smoothing capacitor 203 is supplied in order to extend the supply time of the holding voltage to the first load circuit 20. Therefore, the smoothing capacitor 203 to be mounted can be downsized and reduced in price.

  Note that the switching power supply 1 is configured by combining the first power supply circuit 2 and the second power supply circuit 3 into a two-system circuit, but a plurality of systems of three or more systems may be connected in parallel. Also in this case, it is possible to realize the same function for all systems by adding the same number of diodes (202, 302,...) As the number of parallel circuits (2, 3,...). The switching power supply 1 having a protection function can be manufactured in a small size and at low cost.

In correspondence between the configuration of the present invention and the above-described embodiment,
The first circuit of the present invention corresponds to the first power supply circuit 2 of the embodiment,
Similarly,
The second circuit corresponds to the second power supply circuit 3,
The first load corresponds to the load that needs to hold the voltage connected to the first load circuit 20,
The second load corresponds to a load that does not require voltage holding and is connected to the second load circuit 30.
The switching circuit corresponds to the determination circuit 110, the short circuit 120, the integration circuit 130, and the MOSFET 141,
The fixed time corresponds to the time until the capacitor 133 is charged,
The timer circuit corresponds to the integration circuit 130 including the capacitor 133,
The rectifier circuit corresponds to a circuit including the diode bridge 201 and a circuit including the diode bridge 301,
The voltage supply stabilization circuit corresponds to a circuit including the diode 202,
The first smoothing element corresponds to the smoothing capacitor 203,
The second smoothing element corresponds to the smoothing capacitor 303,
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

The circuit diagram of a switching power supply. The circuit diagram of a switching power supply. The circuit diagram of a switching power supply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Switching power supply 2 ... 1st power supply circuit 3 ... 2nd power supply circuit 20 ... 1st load circuit 30 ... 2nd load circuit 110 ... Judgment circuit 120 ... Short circuit 130 ... Integration circuit 133 ... Capacitor 141 ... MOSFET
201, 301 ... Diode bridge 202 ... Diode 203, 303 ... Smoothing capacitor

Claims (4)

A rectifier circuit that rectifies the input AC voltage into a DC voltage;
A first circuit for smoothing and supplying a DC voltage to a first load having a high need for protection by a first smoothing element;
A switching power supply comprising: a second circuit that supplies a DC voltage to a second load that is less required to be protected than the first load by a second smoothing element;
A switching power supply comprising a switching circuit for switching so as not to supply voltage to at least the first smoothing element and the second smoothing element when the input voltage is an overvoltage. A voltage supply stabilization circuit for preventing a voltage from being supplied from the first smoothing element that supplies a smoothing voltage to the first load to a load other than the first load when an input voltage is cut off. The switching power supply according to Item 1. 3. The switching power supply according to claim 1, further comprising a timer circuit that prevents voltage from being supplied to the first smoothing element and the second smoothing element until a predetermined time has elapsed. The switching power supply according to claim 3, wherein the timer circuit is disposed in the second circuit.

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