JP5048540B2 - AC / DC power input circuit - Google Patents

Description

  AC / DC power input circuit that automatically switches the internal circuit and outputs DC to external electrical equipment, especially when DC is input to one input terminal or AC is input as the power supply voltage About.

Conventionally, a control unit of a press machine installed in a press line place of an automobile factory has been used with an AC 100V as a power source. Recently, a control unit using a DC 24V as a power source is widely used due to the digitization of the control unit. It is provided. For this reason, in the electronic device connected to a press machine and its related devices and fed from the control unit, two types are required: an electronic device using AC 100V as a power source and an electronic device using DC 24V as a power source.
In this case, since two types of electronic devices must be purchased and used according to the power supply voltage, it is troublesome in various aspects.

  By the way, in the metal mold | die used for the said press machine, the gas spring may be integrated in the metal mold | die inside. In this case, a gas pressure monitoring device is used to detect and display the gas pressure of the gas spring, and the gas pressure is displayed even when the press machine is in operation. This gas pressure monitoring device is driven by DC24V, but since power is supplied from the control unit of the press machine, it is desirable that this gas pressure monitoring device can handle AC100V power and DC24V power.

For example, there is an AC / DC power supply device described in Patent Document 1. This power supply apparatus is configured such that an AC power supply and a DC power supply can be connected to separate input terminals, and the insulation transformer T inside the power supply apparatus is used as an AC / DC converter by the first switching circuit 11 when the AC power supply is used. When the DC power supply is operated, the AC / DC power supply apparatus operates as a DC / DC converter by the second switching circuit 12 and outputs a DC voltage.
JP-A-5-161351

  However, the above-described AC / DC power supply apparatus requires two sets of input terminals, ie, a DC input terminal and an AC input terminal, and thus the number of input terminals is large and the structure is complicated. Further, there is a risk that an operator may make a mistake in connecting the DC power supply to the AC input terminal or connecting the AC power supply to the DC input terminal, which is not convenient. If a DC power source is connected to the AC input terminal, the transformer may break down.

  By the way, it is very convenient if AC100V and DC24V can be input to a common input terminal. However, it is estimated that such an electric circuit requires a plurality of expensive IC elements such as power transistors. Therefore, the manufacturing cost becomes expensive, and the volume of the power supply device increases due to a plurality of IC elements, which is not suitable for practical use.

  An object of the present invention is an AC / DC power supply input circuit in which both AC / DC power supplies can be connected to one input terminal, and has a small and simple circuit configuration that can be switched automatically and does not use an IC element. An AC / DC power input circuit is provided.

  The AC / DC power input circuit according to claim 1 is an AC / DC power input circuit that outputs direct current to an external electric device regardless of whether direct current is inputted as a power supply voltage or alternating current is inputted. Alternatively, an input line to which alternating current is input, a transformer connected to the primary side of the input line, an AC / DC converter connected to the secondary side of the transformer, and an output terminal of the AC / DC converter A connected DC output line; a pair of DC supply lines branched from the input line and connected to a DC output line; and the negative input side of the input line that is a negative side during DC input. An input switching circuit comprising an input switching circuit in which a capacitor, a first drive part of the first relay, and a second contact part of the second relay are connected in parallel, and the pair of DC supply lines. A pair of first contact portions of the mounted first relay; And a second drive unit of a second relay connected to the positive electrode side line and the negative electrode side line of the flow output line.

  When a direct current is input to the power input circuit, the first drive unit of the first relay is activated, and the pair of first contact portions interposed in the pair of power supply lines is turned on. The DC supply line and the DC output line constitute a circuit for supplying a direct current, and the direct current input to the input line is directly output to an external electric device. At this time, the first drive unit of the first relay also has resistance, and the voltage divided by the first drive unit is applied to the primary side of the transformer, but the transformer is not driven by DC. Therefore, the output on the secondary side of the transformer becomes zero voltage, and the second drive unit does not operate.

  When alternating current is input to the power input circuit, alternating current flows through the capacitor to the input line. Therefore, the transformer operates, the second drive unit of the second relay operates, and the second contact unit turns on. The input line, the transformer, the AC / DC converter, and the DC output line constitute a circuit for supplying direct current. The alternating current input to the input line is transformed by the transformer, rectified by the converter, and then the direct current output line. Direct current is output to an external electrical device.

  The input switching circuit has a configuration in which a capacitor, a first drive part of the first relay, and a second contact part of the second relay are connected in parallel. When a direct current is input, the capacitor is charged. Therefore, the first driving unit operates with a delay. When alternating current is input, alternating current flows through the input line through the capacitor, the first drive unit does not operate, the second drive unit is turned on by the second drive unit, and the capacitor and the first drive unit are short-circuited. Is done.

  According to a second aspect of the present invention, there is provided the AC / DC power supply input circuit according to the first aspect, wherein the first connection point of the second drive unit of the second relay connected to the positive electrode side line of the DC output line and the DC output line A diode is provided between the positive electrode side line and the second connection point of the positive electrode side DC supply line.

  The AC / DC power supply input circuit according to claim 3 is the invention according to claim 1 or 2, wherein the first capacitor connected in parallel to the output terminal of the AC / DC converter, and the second drive unit of the second relay. And a second capacitor connected in parallel on the output side.

  According to a fourth aspect of the present invention, there is provided the AC / DC power input circuit according to any one of the first to third aspects, wherein the AC / DC power input circuit displays the gas pressure of the gas spring provided in the mold. It is characterized by being incorporated in a gas pressure monitoring device as a power input circuit.

  According to the first aspect of the present invention, when direct current is input to the AC / DC power supply input circuit, the divided voltages are respectively applied to the primary side of the transformer and the first drive section of the first relay. Therefore, the first contact part is turned on by the first drive part, and the input line and the direct current output line can be directly connected via a pair of direct current supply lines, and a circuit for supplying direct current can be configured. .

When alternating current is input to this power input circuit, alternating current flows through the input line through the capacitor, so that the transformer operates and from the secondary side to the second drive unit of the second relay through the AC / DC converter. Since the voltage can be applied, the second contact part is turned on by the second drive part, the first drive part and the capacitor are short-circuited, and direct current is supplied from the input line, the transformer, the AC / DC converter, and the direct current output line. Circuit can be configured.
As described above, when a direct current is input to the common input line, a direct current is generated at the direct current output line, and when an alternating current is input, a direct current is generated at the direct current output line. Therefore, it is possible to input power to the input line without distinguishing between a DC power supply and an AC power supply.

  When a direct current is input to the capacitor of the input switching circuit, this capacitor is charged first, so that a delay can be added to the driving of the first drive unit, and the startup stability of the power input circuit is improved. Can be made. When an alternating current is input, there is no instantaneous voltage change with respect to the first drive unit due to the bypass function of the capacitor, so that the malfunction of the first relay can be prevented. In addition, since the second contact portion is turned on by the second drive portion and the capacitor and the first drive portion are short-circuited, double malfunctions are prevented together with the capacitor.

  This power supply input circuit can automatically switch the circuit even if AC or DC is input by the input switching circuit, so that a compact power input circuit with inexpensive components without using expensive IC elements. Manufacturing cost can be suppressed.

  According to invention of Claim 2, the 1st connection point of the 2nd drive part of the 2nd relay connected to the positive electrode side line of a DC output line, and the 2nd connection of the positive electrode side line of a DC output line, and a positive electrode side DC supply line Since the diode is provided between the point and the point, the second drive unit can be isolated from the circuit supplying the direct current so that the second drive unit of the second relay is not driven when the direct current is input.

  According to a third aspect of the present invention, the first capacitor connected in parallel to the output terminal of the AC / DC converter, and the second capacitor connected in parallel to the output side of the second drive unit of the second relay are provided. Therefore, the operating voltage of the second drive unit of the second relay can be filtered by the first capacitor, and the full-wave rectified DC voltage output from the AC / DC converter can be filtered by the second capacitor. Can do.

  According to the invention of claim 4, this AC / DC power input circuit is incorporated in the gas pressure monitor device as a power input circuit of a display device that displays the gas pressure of the gas spring provided in the mold. The gas pressure monitor device can be automatically switched by this power input circuit to supply a DC voltage to the display device of the gas pressure monitor device, regardless of whether an AC or DC power source is connected to the input line.

  The present invention is an AC / DC power input that outputs DC to an external electrical device (in the present invention, a display of a gas pressure monitoring device) regardless of whether DC is input as a power supply voltage or AC is input. Circuit. Hereinafter, it demonstrates in detail based on drawing.

First, a gas pressure monitoring device 1 (hereinafter referred to as a monitoring device) in which the power input circuit 10 according to the first embodiment is incorporated will be described.
As shown in FIGS. 1 and 2, the monitoring device 1 is for detecting and displaying the gas pressure of the gas spring 4 which is supplied with electric power from the control unit 2 of the press machine and incorporated in the mold. The main body case 6, the liquid crystal display 7 (corresponding to a display device), the first connection portion 8 a connected to the gas supply source 3 via the gas hose 3 a, and the gas spring 4 connected via the gas hose 4 a A second connecting portion 8b, a gauge portion 9, a connection portion (not shown) to which an electric cable 2a that combines the power supply system and signal system from the control unit 2 is connected, and an input line connected to the connection portion. An AC / DC power supply input circuit 10 (hereinafter abbreviated as a power supply input circuit) to which 12a and 12b are connected is constituted.

  Compressed gas (for example, nitrogen gas) is supplied / exhausted from the gas supply source 3 to the gas working chamber of the gas spring 4 through the monitor device 1. It is always displayed on the gauge unit 9. This monitoring device 1 has a function of a pressure switch, and when the gas pressure becomes a certain value or less, a stop signal is transmitted to the control unit 2 via the electric cable 2a, and the press machine is urgently stopped.

Here, the power input circuit 10 for driving the display 7 will be described.
As shown in FIG. 3, the power input circuit 10 includes input lines 12a and 12b to which alternating current or direct current is input from the control unit 2 via the electric cable 2a, a transformer 13, an AC / DC converter 14, and direct current. Are constituted by a DC output line 16a, 16b, a pair of DC supply lines 17a, 17b, an input switching circuit 19, first and second relays 21, 22 and the like. An AC or DC power source can be connected to the power input circuit 10 according to the power source of the control unit 2 of the press machine.

  When alternating current is input to the power input circuit 10, the second drive unit 22a of the second relay 22 is driven to turn on the second contact unit 22b, and the first drive unit 21a of the first relay 21 is short-circuited. The input lines 12a and 12b, the transformer 13, the AC / DC converter 14, and the DC output lines 16a and 16b constitute a circuit for supplying direct current. When a direct current is input, the first drive portion 21a of the first relay 21 is driven, and the first contact portions 21b and 21c interposed between the pair of power supply lines 17a and 17b are turned on. 12a, 12b, a pair of DC supply lines 17a, 17b and DC output lines 16a, 16b constitute a circuit for supplying DC.

  The input lines 12a and 12b are connected to a connecting portion provided on the side surface of the main body case 6, and AC or DC (for example, AC 100V or DC 24V) is input from the control unit 2 through the electric cable 2a. A primary side 13a of a transformer 13 described later is connected to the input line 12a, and an input switching circuit 19 is connected to the input line 12b. When direct current is input, the negative electrode side input line 12b is connected to the ground via the direct current supply line 17b.

  The transformer 13 is a component that occupies more than half of the weight of the board on which the power input circuit 10 is formed. The primary side 13a of the transformer 13 is connected to the input lines 12a and 12b and is connected to the secondary side. 13 b is connected to the AC / DC converter 14. The turn ratio of the transformer 13 is smaller on the secondary side 13b than on the primary side 13a, and functions as a step-down transformer.

  The AC / DC converter 14 includes four diodes 14a to 14d, and operates when AC is input to the input lines 12a and 12b. The converter 14 receives the AC voltage stepped down by the transformer 13, rectifies the AC voltage in a full wave, and outputs DC to the DC output lines 16 a and 16 b connected to the output terminals. When a DC voltage is input, the secondary side 13b of the transformer 13 does not operate because it is zero voltage.

  The direct current output lines 16a and 16b are connected to the output end of the AC / DC converter 14 and the direct current supply lines 17a and 17b. When direct current is input to the input lines 12a and 12b, direct current is supplied to the display display 7. When direct output is performed and an alternating voltage is input, the direct current converted through the transformer 13 and the converter 14 is output to the display 7. The DC output line 16b on the negative electrode side is connected to the ground.

  The pair of DC supply lines 17a and 17b are branched from the positive electrode side 12a and the negative electrode side 12b of the input lines 12a and 12b, respectively, and are connected to the positive electrode side 16a and the negative electrode side 16b of the DC output lines 16a and 16b, respectively. A first contact part 21b of the first relay is interposed in the middle part of the DC supply line 17a, and a first contact part 21c is interposed in the middle part of the DC supply line 17b.

  The input switching circuit 19 can automatically switch the circuit in accordance with the input voltage. The input switching circuit 19 is a negative input line that becomes a negative input side during DC input of the input lines 12a and 12b. 12b, and has a circuit configuration in which the capacitor 20, the first drive unit 21a of the first relay 21, and the second contact unit 22b of the second relay 22 are connected in parallel.

  The capacitor 20 has a function of bypassing the start-up voltage by charging / discharging when an AC voltage is input, and the primary side 13a of the transformer 13 is not applied to the first drive unit 21a. Can be applied with a voltage. At the time of start-up when a DC voltage is input, the capacitor 20 is first charged, so that the operation of the first drive unit 21a can be delayed.

Here, the first and second relays 21 and 22 will be described.
The first relay 21 has a first drive part 21a and a pair of first contact parts 21b and 21c. When a direct current is input, the first drive part 21a operates with a delay due to charging of the capacitor 20. Then, since the pair of first contact portions 21b and 21c are turned on, the input lines 12a and 12b are connected to the DC output lines 16a and 16b.

  The second relay 22 includes a second drive unit 22b and a second contact unit 22c. When an AC voltage is input, the AC / DC converter is activated as soon as a voltage is generated on the secondary side 13b of the transformer 13. Actuated, the second drive portion 22a is actuated, and the second contact portion 22b is turned on, so that the input switching circuit 19 is short-circuited.

  In these relays 21, 22, each drive unit 21a, 22a is composed of a light emitting element such as a photodiode. Therefore, when a voltage is applied, the voltage can be converted into light, and each contact unit 21b, 22b, 22c Since it is composed of a light receiving element such as a transistor, each contact portion 21b, 21c, 22b can be turned on by causing the light receiving element to receive light. Thus, since these relays 21 and 22 are constituted by MOS relays, the power input circuit 10 can be manufactured in a small size.

  The diode 24 includes a first connection point 24a of the second drive unit 22a of the second relay 22 connected to the positive electrode side line 16a of the DC output lines 16a and 16b, a positive electrode side line 16a of the DC output lines 16a and 16b, and a positive electrode DC. Provided in the forward direction between the second connection point 24b of the supply line 17a and when alternating current is input, direct current is output via the diode 24, and when direct current is input, the diode 24 2 The drive unit 22a can be separated from the DC circuit so as not to operate.

  The first capacitor 26 is connected in parallel to the output terminal of the AC / DC converter 14, and the capacitor 26 performs light filtering so as not to fall below the threshold of the operating voltage of the second drive unit 22 a. The second capacitor 27 has a larger capacity than the first capacitor and is connected in parallel to the output side of the second drive unit 22a. The capacitor 27 re-filters the voltage that has been full-wave rectified by the converter 14. Can do.

Next, the operation and effect of the power input circuit 10 will be described.
The gas pressure monitor apparatus 1 incorporating the power input circuit 10 first displays the gas pressure of the gas spring 4 mounted on the die of the press machine, and first, via the electric cable 2a, to the control unit 2 of the press machine. The power supply voltage is supplied to the input lines 12a and 12b of the power input circuit 10. As a power supply voltage from the control unit 2, an AC voltage (AC100V) or a DC voltage (DC24V) is supplied according to the power supply of the press machine.

  Next, the gas hose 3a from the gas supply source 3 provided outside the press machine is connected to the first connecting portion 8a, and the gas hose 4a connected to the second connecting portion 8b is connected to the gas supply / exhaust hole of the gas spring 4. By connecting, gas can be supplied and discharged via the gas pressure monitor device 1. For this reason, the gas pressure can always be displayed on the display 7 and the gauge unit 9.

  Here, when a direct current is input to the power input circuit 10, the first drive unit 21a is activated and a pair of first contact portions 21b interposed between the pair of power supply lines 17a and 17b, 21c is turned on, and the input lines 12a and 12b, the DC supply lines 17a and 17b, and the DC output lines 16a and 16b can constitute a circuit for supplying DC, and the DC input to the input lines 12a and 12b. Is directly output to the liquid crystal display 7. At this time, the first drive unit 21a also has resistance, and a voltage divided by the first drive unit 21a is applied to the primary side 13a of the transformer 13, but the transformer 13 is not driven by direct current. For this reason, the output of the secondary side 13b of the transformer becomes zero voltage, and the second drive unit 22 does not operate.

  Further, when alternating current is input to the power input circuit 10, alternating current flows to the input lines 12 a and 12 b through the capacitor 20, so that the transformer 13 is activated and the second drive unit 22 a of the second relay 22. And the second contact 22b is turned on, and a circuit for supplying direct current can be configured by the input lines 12a and 12b, the transformer 13, the AC / DC converter 14, and the direct current output lines 16a and 16b. The alternating current input to the lines 12 a and 12 b is transformed by the transformer 13, rectified by the converter 14, and direct current is output from the direct current output lines 16 a and 16 b to the liquid crystal display 7.

  In this way, even when a direct current is input to the common input lines 12a and 12b, a direct current is generated at the direct current output line, and a direct current is generated at the direct current output lines 16a and 16b even when an alternating current is input. For this reason, it is possible to input power to the input lines 12a and 12b without distinguishing between a DC power supply and an AC power supply.

  The capacitor 20 of the input switching circuit 19 is initially charged when a direct current is input, so that the operation of the first drive unit 21a can be delayed (about 90 ms). 10 start-up stability can be improved. When alternating current is input, alternating current flows through the capacitor 20 to the input lines 12a and 12b, and there is no instantaneous voltage change with respect to the first drive unit 21a due to the bypass function of the capacitor. The malfunction of the 1st relay 21 is prevented, without the part 21a act | operating. Further, since the second contact portion 22b is turned on by the second drive portion 22a and the capacitor 20 and the first drive portion 21a are short-circuited, the double malfunction is prevented together with the capacitor 20.

  Since the power input circuit 10 is incorporated in the gas pressure monitor device 1 as the power input circuit 10 of the display 7 that displays the gas pressure of the gas spring 4 provided in the mold, the gas pressure monitor device 1 Even if an AC or DC power supply is connected, the power input circuit 10 can automatically switch and use the AC or DC power supply.

  Since the power input circuit 10 can automatically switch the circuit even when AC or DC is input by the input switching circuit 19, it is possible to use a small power source with inexpensive components without using expensive IC elements. Since the input circuit 10 can be manufactured, manufacturing cost can be suppressed.

Next, a modified example in which the above embodiment is partially modified will be described.
1] Although the power input circuit 10 is applied to the display 7 of the gas pressure monitor device 1 that displays the gas pressure, it may be applied to a display device that displays the hydraulic pressure, and requires another DC voltage. The present invention may be applied to various devices.
2] The first and second relays 21 and 22 are static relays in which the first and second drive units 21a and 22a are configured by coils, and the first and second contact units 21b, 21c and 22b are configured by iron cores. It may be configured.
3] In addition, those skilled in the art can implement the present invention by adding various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. .

It is a front view of the gas pressure monitor apparatus which concerns on Example 1 of this invention. It is a side view of a gas pressure monitor device. It is a circuit diagram of the power input circuit of the display apparatus of a gas pressure monitor apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas pressure monitor apparatus 2 Control unit 7 Display 10 Power input circuit 12a, 12b Input line 13 Transformer 14 AC / DC converter 16a, 16b DC output line 17a, 17b DC supply line 19 Input switching circuit 20 Capacitor 21 1st Relay 21a 1st drive part 21b, 21c 1st contact part 22 2nd relay 22a 2nd drive part 22b 2nd contact part 24 Diode

Claims (4)

In the AC / DC power input circuit that outputs direct current to an external electrical device, whether direct current is input as a power supply voltage or alternating current is input,
An input line to which direct current or alternating current is input;
A transformer whose primary side is connected to this input line;
An AC / DC converter connected to the secondary side of the transformer;
A DC output line connected to the output end of the AC / DC converter;
A pair of DC supply lines branched from the input line and connected to a DC output line;
An input switching circuit provided on a negative electrode side input line that is a negative electrode side during direct current input among the input lines, a capacitor, a first drive unit of a first relay, and a second contact unit of a second relay; Input switching circuit connected in parallel,
A pair of first contact portions of a first relay interposed in the pair of DC supply lines;
A second drive unit of a second relay connected to the positive electrode side line and the negative electrode side line of the DC output line;
An AC / DC power input circuit characterized by comprising:   A diode is connected between the first connection point of the second drive unit of the second relay connected to the positive electrode side line of the DC output line and the second connection point of the positive electrode side line of the DC output line and the positive electrode side DC supply line. 2. The AC / DC power input circuit according to claim 1, wherein the AC / DC power input circuit is provided.   The first capacitor connected in parallel to the output terminal of the AC / DC converter, and the second capacitor connected in parallel to the output side of the second drive unit of the second relay. Item 3. The AC / DC power supply input circuit according to Item 1 or 2. 4. The AC / DC power supply input circuit is incorporated in a gas pressure monitor device as a power supply input circuit of a display device for displaying the gas pressure of a gas spring provided in a mold. The AC / DC dual-purpose power input circuit according to claim 1.