WO2008001644A1

WO2008001644A1 - Polarity switching circuit and feeding unit

Info

Publication number: WO2008001644A1
Application number: PCT/JP2007/062283
Authority: WO
Inventors: Tadashi Matsumoto; Shoji Koise
Original assignee: Panasonic Electric Works Co., Ltd.
Priority date: 2006-06-27
Filing date: 2007-06-19
Publication date: 2008-01-03
Also published as: CN101479907A; CN101479907B; JP4925363B2; JPWO2008001644A1

Abstract

A polarity switching circuit capable of adding a DC power source to a feeding line with a correct polarity without requiring a check of the polarity of a feeding system connected to a load. The polarity switching circuit lies between the DC power source and the load and connects the DC power source to two feeding conductors connected to the load. Four switches are bridge-connected between two input terminals connected to the DC power source and two output terminals connected to the feeding conductors. Two switches are turned on and the remaining two switches are turned off depending on the polarity of the feeding conductor connected to the first output terminal.

Description

Specification

Polarity switching circuit and feed unit

Technical field

[0001] The present invention is connected to a DC power supply which applies a DC voltage to two feed conductors, and a polarity switching circuit for matching the polarity of this DC power supply with the polarity of the feed conductor, and this polarity switching circuit. The present invention relates to a power supply unit provided with

Background art

Recently, as a large number of electric devices operated by DC power supply are used in a facility such as a house or a building, a plurality of electric devices can be connected to one power supply system including two power supply conductors. There is a growing need to connect in parallel, and as the number of electrical devices connected to the feed system increases, it is required to add DC power to the feed system. In this case, it is desirable to use a polarity switching circuit to make the polarity of the DC power supply correspond to the polarity of the feeding system.

[0003] Japanese Patent Laid-Open Publication No. Hei 5-30641 discloses a polarity switching circuit for connecting a DC voltage source with a correct polarity to a load operated by a DC power supply. The polarity switching circuit is disposed between the feed line and the DC power supply, and includes a pair of input terminals connected to the DC power supply and a pair of output terminals connected to the load, and the polarity of the polarity of the input terminal is Even if it is unknown whether one of the input terminals is connected to the positive electrode or the negative electrode of the DC power supply, the polarity of the polarity is such that the positive electrode of the DC power supply is always connected to one of the output terminals. Are configured to switch. Therefore, one of the output terminals is set to the positive electrode terminal connected to the positive electrode of the load, and the other is set to the negative electrode terminal connected to the negative electrode of the load, and it is necessary to correctly connect to the load. Therefore, when connecting the DC power supply and load with the correct polarity when adding a DC power supply to the feed line, the person performing the work should connect the positive and negative sides of the feed conductor without mistaken output terminals. There is a problem that confirmation of this polarity is troublesome. On the other hand, when this polarity switching circuit is included in advance for all the loads, the characteristics of this polarity switching circuit can be used to add DC power without confirming the polarity. , Connected to one feeding system Since the number of loads is greater than the number of DC power supplies connected here, providing such a polarity switching circuit for all loads causes an increase in the cost of the entire system, and also connects a wide variety of loads. There is a problem of losing the degree of freedom of the system that can

Disclosure of the invention

The present invention has been made in view of the above problems, and an object of the present invention is to correct a DC power supply without checking the polarity of a power feeding system to which a load is connected. !, Polarity To provide a polarity switching circuit that can be added to the feed system.

In the polarity switching circuit according to the present invention, the DC power supply is connected to two feed conductors connected to the load, interposed between the DC power supply and the load.

Positive input terminal IN + connected to the positive electrode of the DC power supply;

A negative input terminal IN− connected to the negative electrode of the DC power supply;

A first output terminal OUT1 connected to one of the two feed conductors;

A second output terminal OUT2 connected to the other of the two feed conductors;

A first switch SW1 inserted between the positive input terminal and the first output terminal; a second switch SW2 inserted between the positive input terminal and the second output terminal; the negative input terminal; With a third switch SW3 inserted between the first output terminal

A fourth switch SW4 inserted between the negative input terminal and the second output terminal is provided.

The first switch SW1 and the fourth switch SW4 become conductive when the voltage applied to the first output terminal OUT1 is higher than the voltage applied to the second output terminal, and the positive input is switched. The terminal IN + (the positive electrode of the DC power supply) is connected to the first output terminal OUT1, and the negative input terminal IN- (the negative electrode of the DC power supply) is connected to the second output terminal OUT2.

The second switch SW2 and the third switch SW3 become conductive when the voltage applied to the first output terminal OUT1 is smaller than the voltage applied to the second output terminal OUT2, and the positive switch An input terminal IN + (positive electrode of DC power supply) is connected to the first output terminal, and a negative input terminal IN− (negative electrode of DC power supply) is connected to the second output terminal.

[0007] Therefore, in a feeding system in which a load and a DC power supply are already connected to two feeding conductors, When adding a new DC power supply, if one of the feed conductors in this system is the positive pole, the output of the positive pole of the additional DC power source is given to one output terminal connected to the feed conductor, If the first output terminal is a negative electrode, the negative electrode of an additional DC power source is given here. That is, in the polarity switching circuit of the present invention, the polarity in which the first output terminal and the second output terminal are connected can be recognized, and the polarity of the output of the DC power supply can be made to coincide with this polarity. Therefore, when adding a DC power supply to the power supply system, the polarity switching circuit can be connected to the existing power supply system without checking in advance the polarity of the output terminal of the polarity switching circuit, thus facilitating connection work. It can be carried out.

If this polarity switching circuit is prepared as a power supply unit in combination with a DC power supply, it can be incorporated into an existing power supply system together with a DC power supply that does not care about the polarity at the time of connection work.

[0009] Preferably, in the embodiment, the first switch includes a first switching element having a control end G, and the first switching element is between the control end and the positive input terminal. It is configured to conduct when a voltage less than a predetermined value is applied. Similarly, the second switch includes a second switching element having a control end G, and the second switching element receives a voltage less than a predetermined value between the control end and the positive input terminal. The third switch includes a third switching element having a control end G. The third switching element has a voltage between the control end and the positive input terminal that exceeds a predetermined value. The fourth switch is configured to conduct when applied, and the fourth switch includes a fourth switching element having a control end G, and the fourth switching element has a predetermined value between the control end and the positive input terminal. It is configured to conduct when an over voltage is applied.

The control end of the first switching element and the control end of the third switching element are both connected to the second output terminal OUT2, and the control end of the second switching element and the control of the fourth switching element Both ends are connected to the first output terminal OUT1. The first switch applies a control voltage equal to or greater than the predetermined value of the positive electrode force to the control end of the first switching element and delays the control voltage for a predetermined time to apply a voltage less than the predetermined value to the control end. A first delay circuit (Rl, C1) is provided. The above second switch is the above second switch. A second delay circuit (R2, C2) for applying a voltage less than the predetermined value to the control end after giving a control voltage of the positive value to the control end of the positive electrode and delaying the control time for a predetermined time .

Therefore, when the voltage applied to the first output terminal is larger than the voltage applied to the second output terminal, a low voltage is applied to the control end of the first switching element, and the second switching element A high voltage is applied to the control end of. As a result, the first switching element is made conductive to cut off the second switching element, whereby the positive electrode of the DC power supply is connected to the first output terminal. Similarly, when the voltage applied to the first output terminal is smaller than the voltage applied to the second output terminal, the first switching element is cut off, the second switch element is turned on, and the second output is turned on. The positive terminal of the DC power supply is connected to the terminal.

On the other hand, when the voltages applied to the first output terminal and the second output terminal are equal to each other, the first delay circuit and the second delay circuit operate together, but due to the delay by the first delay circuit The delay time of the second delay circuit is also increased. That is, when the DC power supply is connected to the power supply system first, and the polarity of the feed conductor is not determined yet, the delay in the first delay circuit is shorter than that in the second delay circuit, so the first switching is performed. The voltage applied to the control end of the element is accelerated to drop below a predetermined value, and the first switching element conducts earlier than the second switching element, and the DC power source positive electrode is applied to the first output terminal. It takes place preferentially. Once a positive electrode is applied to the first output terminal, a control voltage equal to or greater than a predetermined value is applied to the control end of the second switching device to shut off the second switching device, making the first output terminal positive. Determine the second output terminal as the negative electrode. As described above, when the DC power supply is connected to the power supply system for the first time, the power supply conductor connected to the first output terminal can be preferentially used as the positive electrode, and standardization of the power supply system can be achieved and standardized. Based on the polarity, a load can be connected to the feed system. Preferably, the first switching element and the second switching element are formed of FETs having parasitic capacitance between the gate and the source. The source of the first switching element is coupled to the positive input terminal, the drain is connected to the first output terminal, and the source is turned on when the source voltage is higher than the gate voltage by a predetermined value, Connected to the first output terminal. In this case, the first delay circuit is in series with the parasitic capacitance C1 and the parasitic capacitance. A connection point between the first resistor R1 and the parasitic capacitance C1 is connected to the gate G, which is composed of a first resistor R1 inserted between the positive input terminal and the second output terminal. The source of the second switching element is coupled to the positive input terminal, the drain is connected to the second output terminal, and the source voltage is turned on when the source voltage is higher than the gate voltage by a predetermined value, The child IN + is connected to the second output terminal OUT2. The second delay circuit (R2, C2) comprises the parasitic capacitance C2 and a second resistor R2 inserted in series with the parasitic capacitance between the positive input terminal IN + and the first output terminal OUT1. A connection point between the second resistor and the parasitic capacitance is connected to the gate G. Since the resistance value of the first resistor R1 is smaller than the resistance value of the second resistor R2 and the time constant of the first delay circuit is smaller than the time constant of the second delay circuit, the delay by the first delay circuit is caused. The delay time by the second delay circuit is longer than the delay time. As described above, each delay circuit can be configured by utilizing the parasitic capacitance intrinsically provided by the FET, and the switching circuit having the above function can be configured with the minimum number of parts.

Also, if the DC power is also supplied with a voltage that exceeds the allowable gate'source voltage at the FET, a voltage divider resistor is used to protect the FET. That is, a first voltage dividing resistor is connected in series with the first resistor R1 between the positive input terminal IN + and the second output terminal, and between the first resistor R1 and the first voltage dividing resistor R11 The gate of the first switching element is connected to the connection point of Similarly, a second voltage dividing resistor is connected in series with the second resistor R2 between the positive input terminal IN + and the first output terminal, and between the second resistor R2 and the second voltage dividing resistor R21. The gate of the second switching element is connected to the connection point. With this configuration, the gate 'source voltage of the first switching element and the second switching element, which are FETs, can be divided to a predetermined value or less, and the FETs can be protected.

Furthermore, in order to suppress the temperature rise of the FET and protect the FET when the output of the polarity switching circuit of the present invention is accidentally short circuited, the first voltage dividing resistor R11 and the positive input terminal IN + Preferably, a zener diode is inserted, and a second zener diode is inserted between the second voltage dividing resistor R21 and the positive input terminal IN +.

Brief description of the drawings

FIG. 1 is a circuit diagram of a polarity switching circuit according to a first embodiment of the present invention.

[FIG. 2] A block diagram showing a feeding unit incorporating the polarity switching circuit of the same. [FIG. 3] A schematic view showing one usage pattern of the above-mentioned power supply unit.

[FIG. 4] A circuit diagram showing a modification of the polarity circuit of the above.

[FIG. 5] A circuit diagram showing a modification of the polarity circuit of the above.

FIG. 6 is a circuit diagram showing a modification of the polarity circuit of the above.

[FIG. 7] A circuit diagram showing a modification of the polarity circuit of the above.

FIG. 8 is a circuit diagram of a polarity switching circuit according to a second embodiment of the present invention.

FIG. 9 is a circuit diagram of a polarity switching circuit according to a third embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The polarity switching circuit according to the present invention is used in a DC voltage feeding system for supplying a DC voltage to a load driven by a DC voltage, and when a DC power supply is added to the feeding system, the load is connected. It detects the polarity of the two feed conductors and matches the polarity of the DC power supply to the polarity of the feed conductors. The polarity switching circuit 20 is generally incorporated in a power supply unit 40 including a DC power supply 10 as shown in FIG. In the feed system as shown in FIG. 3, a plurality of feed units 40 are connected in parallel with each other to supply a DC voltage, for example, a voltage of 12 V, to the plurality of loads 2 connected to the feed conductors 1A and IB. .

[0014] DC power supply 10 in power supply unit 40 is connected to commercial AC power supply via switch 12, converts an AC voltage to a DC voltage, and converts the DC voltage through polarity switching circuit 20. Power supply conductor 1A , Supplied to IB. As the load 2, one that can perform information communication using this feeding conductor can be used. In this case, as shown in FIG. 3, the termination device 3 is connected to the feeding system, and the feeding unit 40 is connected to the feeding unit 40. As shown in FIG. 2, an impedance adjustment unit 30 is provided to separate the high frequency communication signal flowing to the feed conductors 1A and IB from the polarity switching circuit 20.

First Embodiment

FIG. 1 shows a polarity switching circuit according to a first embodiment of the present invention, and is composed of four MOSFETs. SW1 to SW4 force positive and negative input terminals IN + and IN − and first and second output terminals OUTl , And OUT2 are bridged. The positive input terminal IN + is connected to the positive electrode of the DC power supply 10, and the negative input terminal IN− is connected to the negative electrode of the DC power supply. The first switch SW1 is inserted between the positive input terminal IN + and the first output terminal OUT1, and the source S is Connect to the positive input terminal IN + and connect the drain D to the first output terminal OUT1. The second switch SW2 is inserted between the positive input terminal IN + and the second output terminal OUT2, and the source S is connected to the positive input terminal IN + and the drain D is connected to the second output terminal OUT2. . The third switch SW3 is inserted between the negative input terminal IN− and the first output terminal OUT1, and the source S is connected to the negative input terminal IN− and the drain D is connected to the first output terminal OUT1. . The fourth switch SW4 is inserted between the negative input terminal IN− and the second output terminal OUT2, and the source S is connected to the negative input terminal IN− and the drain D is connected to the second output terminal OUT2. .

The switching elements that are M0SFETs that form the first switch SW1 and the second switch are P-type transistors that conduct when the source voltage is higher than the gate voltage, and the MOSFETs that form the third switch SW3 and the fourth switch SW4 The switching element is an N-type transistor that conducts when the gate voltage is higher than the source voltage.

The gate G of the switching element which is a MOSFET constituting the first switch SW1 is connected to the second output terminal OUT2 together with the gate G of the switching element of the third switch SW3.

The gate G of the switching element constituting the second switch SW2 is connected to the first output terminal OUT1 together with the gate G of the switching element of the fourth switch SW4. The gate of each switching element is a control terminal to which a voltage for determining on / off of each switch is applied, and on / off control of each switch is performed based on the magnitude relationship between the source voltage and the gate voltage. Is done.

The switching elements constituting each switch inherently have parasitic capacitances C1 to C4 between the gate and the source, and the parasitic capacitances Cl and C2 at the first switch SW1 and the second switch SW2 are each 1000 pF, respectively. The parasitic capacitances C3 and C4 at the third switch SW3 and the fourth switch SW4 are 300 pF respectively. This value is merely an example, and can be changed as necessary. The magnitude relation between Cl, C2 and C3, C4 is also reversed between the P-type and N-type switches. is there.

In each switching element, resistors R1 to R4 are respectively connected in series with parasitic capacitances C1 to C4 to form a delay circuit, and a connection point between the resistance and the parasitic capacitance is connected to the gate of each switching element. Ru. Each delay circuit changes the timing at which each switching element becomes conductive by adjusting the charge rate to the parasitic capacitance, and as described later, When the feed unit is first connected to the system, one of the first switch SW1 and the second switch is set to operate preferentially to determine the polarity of the feed conductor 1A, IB.

In the polarity switching circuit 20 of the present invention, when adding a power supply unit to a power supply system already in operation, the voltage output to the first output terminal OUT1 and the second output terminal OUT2 is the current supplied from the power supply conductors 1A and IB. It is intended to match the voltage according to the polarity, and to facilitate the additional connection work of the feed unit 40 by eliminating the need for the operator to check in advance the polarity of the feed conductor.

The operation of the polarity switching circuit in the case where a power supply unit is added to a power supply system already in operation will be described below. In this description, it is assumed that the feeding conductor 1A is a positive electrode to which a voltage of +12 V is applied, the feeding conductor 1B is a negative electrode to which a voltage of 0 V is applied, and the DC power supply supplies a DC voltage of 12 V. .

1) When the first output terminal OUT1 is connected to the positive feed conductor 1A, and the second output terminal OUT2 is connected to the negative feed conductor 1B

In this case, the positive voltage 12 V from the DC power supply is applied to the source S of the first switch SW1 and the second switch SW2, and the source S of the third switch SW3 and the fourth switch are both DC current source 0V is applied. On the other hand, from the feed system, 12 V is applied to the first output terminal OUT1, and 0 V is applied to the second output terminal OUT2.

Therefore, in the first switch SW1, 0 V from the second output terminal OUT2 becomes the gate voltage, and the relationship of gate voltage (0 V) <source voltage (12 V) is satisfied, and the first switch SW1 is turned on. In the second switch SW2, both the gate voltage and the source voltage become 12 V, and the on condition (gate voltage and source voltage) is not satisfied, and the switch SW2 is turned off, and the second switch SW2 is turned off. In addition, in the third switch SW3, both the source voltage and the gate voltage become 0 V, and are turned off because the on condition (gate voltage> source voltage) is not satisfied, and in the fourth switch SW4, the gate voltage (12 V) > The source voltage (0 V) is set, and the fourth switch SW4 turns on. Therefore, only the first switch SW1 and the fourth switch SW4 are turned on, the positive voltage 12V of the DC power is applied to the first output terminal OUT1, and the negative voltage 0V of the DC power is applied to the second output OUT2. The DC power supply with the polarity according to the polarity of the power supply system already in operation. Is added to the feed system.

2) When the first output terminal OUT1 is connected to the negative feed conductor 1B, and the second output terminal OUT2 is connected to the positive feed conductor 1B

In this case, the positive voltage 12 V from the DC power supply is applied to the source S of the first switch SW1 and the second switch SW2, and the source S of the third switch SW3 and the fourth switch are both DC current source Is applied. On the other hand, 0 V is applied to the first output terminal OUT1 from the feed system, and 12 V is applied to the second output terminal OUT2.

Therefore, in the first switch SW1, 12 V from the second output terminal OUT2 becomes the gate voltage, and the on condition (gate voltage and source voltage) is not satisfied, and the switch SW1 is turned off. The second switch SW2 turns on as the gate voltage (OV) and the source voltage (12 V). In the third switch SW3, the gate voltage (12 V)> the source voltage (OV) is turned on. In the fourth switch SW4, both the gate voltage and the source voltage become OV, and the on condition (gate voltage> source voltage) is not satisfied, and it is turned off. Therefore, only the second switch SW2 and the third switch SW3 are turned on, the positive voltage 12V of the DC power is applied to the second output terminal OUT2, and the negative voltage OV of the DC power is applied to the first output terminal OUT2. The DC power supply is added to the power supply system with the polarity according to the polarity of the power supply system already in operation.

3) When connecting the feed unit to the feed system first

In this case, when the feed conductors 1A and IB are both OV and the first output terminal OUT1 and the second output terminal OUT2 of the feed unit 40 are connected to the feed conductor in this state, the first output terminal OUT1 and the second output terminal OUT2 No substantial voltage is applied. Immediately after connection, 12 V is applied to the gates G of the first switch SW1 and the second switch SW2 from the positive electrode input terminal IN + via the parasitic capacitances C1 and C2, charging of the parasitic capacitances Cl and C2 is started. Ru. Immediately after the connection, the first switch SW1 and the second switch SW2 both have a gate voltage of 12 V and a source voltage of 12 V, so the gate parasitic capacitances Cl and C2 are charged. It turns on when the voltage drops below 12V. Here, each charging circuit in each switch is composed of parasitic capacitances Cl and C2 and resistors Rl and R2 connected thereto, and Rl = lkQ, R2 is 2 kΩ, and the charging circuit for the first switch is The time constant of is faster than the second switch. For this reason, the gate voltage of the first switch SW drops faster than the second switch. The first switch turns on early. As a result, 12 V from the DC power supply is applied to the first output terminal OUT1, and accordingly, the gate of the second switch SW2 is fixed at 12 V, and the off state of the second switch SW is determined. Ru. Since the gate voltage and the source voltage are both fixed at OV immediately after connection, the third switch SW3 is kept off. On the other hand, the fourth switch SW4 is turned off immediately after connection because both the gate voltage and the source voltage are 0 V, but the first switch SW1 turns on and the voltage of the first output terminal OUT1 becomes 12 V. When the gate voltage is 12 V, the on condition (gate voltage and source voltage) is satisfied and turned on. Therefore, when the power supply unit is connected to the power supply system for the first time, the positive electrode 12V of the DC power supply is preferentially applied to the first output terminal OUT1. If the relationship between the resistors R1 and R2 is R1 <R2, the second switch SW2 turns on first immediately after connection, the second switch SW2 and the third switch SW3 turn on, and the first switch SW1 and the fourth switch (Ii) The SW4 is turned off to give a positive voltage of 12 V to the second output terminal OUT2, and the negative electrode of OV to the first output terminal OUT1.

In this embodiment, the first switch SW1 is set to turn on earlier than the second switch SW2 with a clear difference between the resistance values of the resistors R1 and R2, but the charge times of each switch are set. Between the paths, due to variations in resistance and parasitic capacitance, it is expected that there will be a difference in time constant. Therefore, using such variations, the pair of the first switch SW1 and the fourth switch SW4, and the fourth switch SW4 are used. It is determined that one of the pair of the 2nd switch SW2 and the 3rd switch SW3 is turned on preferentially to make either of the power supply conductors 1A and IB positive. After that, when adding the feed tube 40, as described above, the polarity of the feed conductors 1A and IB is determined, and the output polarity of the feed unit to be added matches the polarity of the existing feed system. Ru.

By the way, the time constants of the charging circuit of the first switch SW1 and the second switch SW2 are expected to differ depending on the variations of the resistors R1 and R2 and the parasitic capacitances Cl and C2. If the time constant of the charging circuit in the third switch SW3 and the fourth switch SW4 is different due to the variation in resistance and parasitic capacitance, the combination of the first switch SW1 and the fourth switch SW4, It is determined that one of the pair of the second switch SW2 and the third switch SW3 is turned on preferentially, and that one of the feed conductors 1A and IB is used as the positive electrode. That is, after the connection of the power supply unit, the first switch SW1 and the second switch SW2 are both temporarily turned on, and a voltage of 12 V is applied to the first output terminal OUT1 and the second output terminal OUT2. In this case, this voltage is applied between the resistors R3 and R4 and the parasitic capacitances C3 and C4, respectively, between the negative input terminal IN-(0 V) to charge the parasitic capacitances C3 and C4 of each charging circuit. become. In this case, since the source voltage of the third switch SW3 and the fourth switch SW4 is OV of the same potential as that of the negative input terminal, the time constant of the charging circuit of the fourth switch SW4 is that of the charging circuit of the third switch SW3. If it is smaller than the time constant, the charging speed to the parasitic capacitances C3 and C4 differs, and the gate voltage of the fourth switch SW4 rises faster than the third switch SW3, so that the fourth switch SW4 First turns on and determines the second output terminal OUT2 to be negative. As a result, the gate voltage of the third switch SW3 is fixed at OV and becomes equal to the source voltage (OV), so that the third switch SW3 is turned off. At the same time, by fixing the gate voltage of the first switch SW1 to OV, the on state of the first switch SW1 is determined, and accordingly, the first output terminal OUT1 is fixed to 12 V, whereby the second switch SW2 is turned on. The gate voltage is fixed at 12 V, and the second switch SW2 is turned off. As a result, the positive terminal of the DC power supply is provided to the first output terminal OUT1. Similarly, if the time constant of the charging circuit of the third switch SW3 is smaller than the time constant of the charging circuit of the fourth switch SW4, the charging speed to the parasitic capacitances C3 and C4 will be different. The fourth switch SW4 and the first switch SW1 are turned off, the second switch SW2 is turned on, and the positive electrode from the DC power supply is applied to the second output terminal OUT2. . As described above, the time constant of the charging circuit of the first switch and the second switch, and the time constant of the charging circuit of the third switch and the fourth switch, are due to variations in resistances R1 to R4 and parasitic capacitances C1 to C4. Since a difference is expected to occur, it is possible to preferentially assign the positive electrode of the DC power supply to one of the first output terminal OUT1 and the second output terminal OUT2 due to the difference. However, in the present embodiment, in order to provide a consistent and stable operation, the first output is obtained as R1 or R2 or R1 = R2 and R3> R4 (R3 = 2K Ω, R4 = lk Ω). The positive terminal of the DC power supply is output to the terminal OUTl. Of course, if R1> R2 or R1 = R2 and R3 <R4, then the positive terminal of the DC power supply is output to the second output terminal OUT2. 4 to 6 show modifications of the polarity switching circuit described above. In the modification of FIG. 4, the resistors R1 and R2 are connected only to the first switch SW1 and the second switch SW2, and charging is performed. An example is shown in which the paths are formed and the values of R1 and R2 are different, and in the modification of FIGS. 5 and 6, the resistors R3 and R4 are connected only to the third switch SW3 and the fourth switch SW4, An example is shown in which the values of R3 and R4 are different.

In the above embodiment and modifications, an example is shown in which the charging circuit is added to the corresponding switch using the parasitic capacitance of the switching element, but the present invention is not necessarily limited thereto. For example, Make sure to form a charging circuit with a combination of inductor and resistor.

FIG. 7 shows still another modification of the polarity switching circuit of the above-described embodiment. In this modification, R11, R21, R31 and R41 are connected to the resistors R1 to R4 that make up each charge circuit, respectively, and the voltage applied to the gate of each switching element is lowered. It is suppressed. This configuration is useful for protecting the switching device when the output voltage of the DC power supply 10 is, for example, 24 V and exceeds the allowable gate voltage 'source voltage' of the MOSFET used as the switching device.

Hereinafter, specific connection relationships of the voltage dividing resistors will be described. In the first switch SW1, the first voltage dividing resistor R11 is connected in series with the first resistor R1 between the positive input terminal IN + and the second output terminal OUT2, and the first voltage dividing resistor R11 and the first resistor are connected. The gate G of the switching element is connected to the connection point between R1. In the second switch SW2, the second voltage dividing resistor R21 is connected in series with the second resistor R2 between the positive input terminal IN + and the first output terminal OUT1, and the second voltage dividing resistor R21 and the second resistor The gate G of the switching element is connected to the connection point between R2. In the third switch SW3, the third voltage dividing resistor R31 is connected in series with the third resistor R3 between the negative input terminal IN− and the second output terminal OUT2, and the third voltage dividing resistor R31 and the third voltage dividing resistor R31 are connected to each other. The gate G of the switching element is connected to the connection point between the resistors R3. In the fourth switch SW4, the fourth voltage-dividing resistor R41 is connected in series with the fourth resistor R4 between the negative input terminal IN− and the first output terminal OUT1, and the fourth voltage-dividing resistor R41 and the fourth voltage-dividing resistor R41 The gate G of the switching element is connected to the connection point between the four resistors R4.

Furthermore, in this modification, when a short circuit occurs between the first output terminal OUT1 and the second output terminal OUT2, the current flowing to each switching element is limited to destroy the switching element. In order to protect from this, Zener diode ZD1, ZD2, ZD3 and ZD4 are connected in series to each voltage dividing resistance Rll, R21, R31 and R41 respectively. That is, the first Zener diode ZD1 is inserted between the first voltage dividing resistor R11 and the positive input terminal IN +, and the second Zener diode ZD2 is inserted between the second voltage dividing resistor R21 and the positive input terminal IN +. The third Zener diode ZD3 is inserted between the third voltage dividing resistor R31 and the negative input terminal IN-, and the fourth Zener diode ZD4 is inserted between the fourth voltage dividing resistor R41 and the negative input terminal IN- Inserted between

Second Embodiment

FIG. 8 shows a polarity switching circuit according to a second embodiment of the present invention. In this embodiment, a bipolar transistor is used as each of the switches SW1 to SW4, and a control circuit 100 for detecting the potentials of the first output terminal OUT1 and the second output terminal OUT2 to control each switch is provided.

The first switch SW1 is an NPN type bipolar transistor, the collector is coupled to the positive input terminal IN + and the emitter is connected to the first output terminal OUT1, and becomes conductive when the base voltage exceeds the threshold, the positive input terminal Connect IN + to the first output terminal OUT1. The second switch SW2 is an NPN type bipolar transistor, the collector is coupled to the positive input terminal IN +, the emitter is connected to the second output terminal OUT2, and the base voltage becomes higher than the threshold value. Connect terminal IN + to the second output terminal OUT2. The third switch SW3 is a PNP bipolar transistor, which has a collector coupled to the negative input terminal IN-, a emitter connected to the first output terminal OUT1, and a conductor connected when the base voltage is below the threshold. , Connect negative input terminal IN- to 1st output terminal OUT1. The fourth switch SW4 is a PNP bipolar transistor, the collector is coupled to the negative input terminal and the emitter is connected to the second output terminal OUT2, and becomes conductive when the base voltage becomes lower than the threshold value, and the negative input terminal Connect IN- to the 2nd output terminal.

The control circuit 100 is configured to detect the first potential applied to the first output terminal OUT1 and the second potential applied to the second output terminal OUT2 to control the respective switches SW1 to SW4. , To achieve the following functions.

When the first potential is greater than the second potential, a control voltage equal to or greater than the threshold is applied to each base of the first switch SW1 and the third switch SW3, and the second switch SW2 and the fourth switch SW Give each of the four bases a control voltage below the threshold.

ii) When the first potential is smaller than the second potential, a control voltage less than the threshold is applied to the bases of the first switch SW1 and the third switch SW3, and the bases of the second switch SW2 and the fourth switch SW 4 Control voltage above the threshold.

iii) When the first potential and the second potential are the same potential, a control voltage less than the threshold is applied to the bases of the first switch SW1 and the third switch SW3, and the second switch SW2 and the fourth switch SW4 Each base is given a control voltage below the threshold.

In order to realize this function, the control circuit 100 detects a first potential applied to the first output terminal OUT1, and outputs a first detection signal when the first potential is equal to or higher than a predetermined value. A second detection unit (a comparator) that detects a second potential applied to the detection means (comparator) 101 and the second output terminal OUT2, and outputs a second detection signal when the second potential is equal to or higher than a predetermined value. And 102) logic means (NOR gate) 110 for giving a predetermined control voltage to the determination means (OR gate) 130 only when both of the first detection signal and the second detection signal are not simultaneously present. The second detection voltage is commonly applied to the bases of the second switch SW2 and the fourth switch SW4, and is set to the above threshold value or more.

Judgment means 130 applies a drive voltage exceeding the threshold of the base voltage to the bases of the first switch SW1 and the third switch SW3 when receiving at least one of the control voltage and the first detection voltage. Configured

The control circuit 100 includes a resistor R5, a capacitor C5, and a comparator 121, and is provided with a delay means 120. After delaying the control voltage output from the logic means (NOR gate) 110, this is determined. Output to

The operation of the polarity switching circuit according to the present embodiment will be described below. In this description, for the sake of convenience, the output voltage of the DC power supply and the operating voltage in the power supply system are 12 V, and the first detection unit 101, the second detection unit 102, the logic unit 110, the determination unit 130 These outputs are 12 V or 0 V, and in practice they can be different values in terms of circuit design.

1) When the first output terminal OUT1 is connected to the positive feed conductor 1A, and the second output terminal OUT2 is connected to the negative feed conductor 1B Assuming that the voltage applied to the first output terminal OUTl is 12 V, the voltage applied to the second output terminal OUT2 is 0 V, and the reference values at the first detection means 101 and the second detection means 102 are less than 12 V, The first detection means 101 outputs a voltage signal of 12 V as the first detection signal, and the output of the second detection means 102 becomes 0 V and does not output the second detection signal. As a result, the output of the logic means 110 becomes 0 V and does not output the control voltage. Therefore, the delay unit 120 does not operate, and an output of 0 V is input to the determination unit 130. The determination means 130 receives the first detection signal of 12 V from the first detection means 101 and applies a drive voltage of 12 V to the bases of the first switch SW1 and the third switch SW3. As a result, the first switch SW1 is turned on and the third switch SW3 is turned off. On the other hand, the second detection signal is not given to the bases of the second switch SW2 and the fourth switch SW4 because the output from the second detection means 102 is 0 V, and the second switch SW2 is turned off. Switch SW4 is turned on. As a result, only the first switch SW1 and the fourth switch SW4 are turned on, the positive input terminal IN + is connected to the first output terminal OUT1, the negative input terminal IN- is connected to the second output terminal OUT2, DC power is added to the feed system with a polarity that corresponds to the polarity of the feed system that is active.

The output of the first detection means 101 is 0 V and does not output the first detection signal, and the second detection means 102 outputs a 12 V second detection signal. In this case, the output of the logic means 110 is 0V, the control voltage is not output, the delay circuit 120 does not operate, and one input of the determination means 130 is 0V. Since 0 V output from the first detection means 101 is input to the other input of the determination means 130, the determination means 130 outputs 0 V and the drive voltage is set to the first switch SW1 and the third switch SW3. Do not give to the base of. As a result, the first switch SW1 is turned off and the third switch SW3 is turned on. On the other hand, the 12V second detection signal from the second detection means 102 is applied to the bases of the second switch SW2 and the fourth switch SW4, the second switch SW2 is turned on, and the fourth switch SW4 is turned off. As a result, only the second switch SW2 and the third switch SW3 are turned on, the positive input terminal IN + is connected to the second output terminal OUT2, and the negative input terminal IN- is connected to the first output terminal OUT1. The DC power supply is added to the power supply system with a polarity according to the polarity of the power supply system. 3) When connecting the feed unit to the feed system first

In this case, when the feed conductors 1A and IB are both OV and the first output terminal OUT1 and the second output terminal OUT2 of the feed unit 40 are connected to the feed conductor in this state, the first output terminal OUT1 and the second output terminal OUT2 The first detection unit 101 and the second detection unit 102 both output OV and do not output the first detection signal and the second detection signal. As a result, the logic means 110 outputs a control voltage of 12 V, and this output is sent to the judging means 130 via the delay circuit 120. The delay means 120 delays the control voltage of 12 V and outputs it to the determination means 130, so that the output of 0 V from the delay means 120 and 0 V from the first detection means 101 are inputted to the determination means 130 first. Although the determination means 130 outputs 0 V and does not give a drive voltage, when the control voltage of 12 V is input from the delay means 120 to the determination means 130, the determination means 130 outputs a 12 V drive voltage. As a result, the first switch SW1 is turned on and the third switch SW3 is turned off. On the other hand, the third switch SW3 is turned off by the 0V output from the second detection means 102, and the fourth switch SW4 is turned on. Therefore, when the power supply unit is connected to the power supply system for the first time, only the first switch SW1 and the fourth switch SW4 are turned on to preferentially apply the positive electrode 12V of the DC power supply to the first output terminal OUT1. become. Third Embodiment

FIG. 9 shows a polarity switching circuit according to a third embodiment of the present invention. In this embodiment, an electromagnetic relay is used as each of the switches SW1 to SW4, and a control circuit 100 similar to that of the second embodiment is provided.

The first switch SW1 is a normally open relay having a drive coil, and the common terminal (COM) is connected to the positive input terminal IN +, the NO contact is connected to the first output terminal, and the drive coil is When energized, the NO contact closes and connects the positive input terminal IN + to the first output terminal OUT1. The second switch SW2 is a normally open relay having a drive coil, and the common terminal (COM) is connected to the positive input terminal IN +, the NO contact is connected to the second output terminal OUT2, and the drive coil is excited. , NO contact closes, connect positive input terminal IN + to second output terminal 0 UT2. The third switch SW3 is a normally closed relay having a drive coil, the common terminal (COM) is connected to the negative input terminal IN−, the NC contact is connected to the first output terminal OUT1, and the drive coil is excited. When open, the NC contact opens and the negative input terminal IN- to the 1st output terminal Disconnect from OUT1. The fourth switch SW4 is a normally closed relay having a drive coil, the common terminal (COM) is connected to the negative input terminal IN−, the NC contact is connected to the second output terminal OUT2, and the drive coil is excited. At the same time, the NC contact opens and disconnects the positive input terminal IN + from the second output terminal OUT2.

As in the second embodiment, the control circuit 100 detects the first potential applied to the first output terminal OUT1, and outputs the first detection voltage when the first potential is equal to or higher than a predetermined value. Detection means 101 and a second detection means 102 for detecting a second potential applied to the second output terminal OUT2 and outputting a second detection voltage when the second potential is equal to or higher than a predetermined value; A logic means is provided for providing a predetermined control voltage to the determining means 130 only when both the detection signal and the second detection signal are not simultaneously present. The control circuit 100 excites drive coils of the first switch SW1 and the third switch SW3 when the first potential is larger than the second potential, and the second potential is larger than the first potential. Energize the drive coil of 2nd switch SW2 and 4th switch SW4. Furthermore, in the control circuit 100, when the first potential and the second potential are the same potential, a predetermined time has elapsed since the first output terminal OUT1 and the second output terminal OUT2 are connected to the feed conductors 1A and IB, respectively. Delay means 120 is provided to excite the drive coils of the first switch SW1 and the third switch SW3 with delay. The second detection voltage from the second detection means 102 is applied to the exciting coil of the second switch SW2 and the fourth switch SW4, and the determination means 130 determines whether the control voltage and the first detection voltage described above are small. When it receives either one of them, it is configured to apply a drive voltage for exciting the exciting coil of the first switch SW1 and the third switch SW3, and the delay means 120 delays this control voltage and applies it to the determination means 130 R5, C5) are provided.

The voltage applied to the first output terminal OUT1 is 12 V, and the voltage applied to the second output terminal OUT2 Is OV and the reference value in the first detection means 101 and the second detection means 102 is less than 12 V, the first detection means 101 outputs a voltage of 12 V as the first detection signal, and the second detection means 102 The output is 0 V and does not output the second detection signal. As a result, the logic means 110 outputs 0 V and the delay means 120 does not operate. The determination means 130 receives the 0V input from the first detection means 101 and the 0V output from the delay means 120 and applies a 12V drive voltage to the drive coils of the first switch SW1 and the third switch SW3. As a result, the NO contact of the first switch SW1 is closed and the NC contact of the third switch SW3 is opened, the positive input terminal IN + is connected to the first output terminal OUT1, and the negative input terminal IN- is the first output. Disconnected from terminal OUT1. On the other hand, the drive coils of the second switch SW2 and the third switch SW3 are not excited because the output from the second detection means 102 is 0 V, and the fourth switch is left open while the NO contact of the second switch SW2 is open. The NC contact of SW4 is kept closed and the negative input terminal IN- is connected to the second output terminal OUT2. As a result, a DC power supply is added to the feed system with a polarity according to the polarity of the feed system already in operation.

The first detection means 101 outputs 0 V and does not output a first detection signal, and the second detection means 102 outputs a 12 V second detection signal. Along with this, the logic circuit 110 outputs 0 V and does not supply the control voltage, so the delay circuit 120 does not operate. Therefore, the determination means 130 outputs 0 V and the drive coils of the first switch SW1 and the third switch SW3 are not excited.

As a result, the first switch SW1 and the third switch SW3 do not operate, the first output terminal OUT1 is disconnected from the positive input terminal IN +, and the negative input terminal IN- is connected to the first output terminal OUT1. On the other hand, the drive coil of the second switch SW2 and the fourth switch SW4 is excited by the second detection signal of 12 V from the second detection means 102, the NO contact of the second switch SW2 is closed, and the NC of the fourth switch SW4. When the contact opens, the positive input terminal IN + is connected to the second output terminal OUT2, and the negative input terminal IN- is disconnected from the second output terminal OUT2. As a result, a DC power supply is added to the power supply system with a polarity according to the polarity of the power supply system already in operation.

3) When connecting the feed unit to the feed system first

In this case, feed conductors 1A and IB are both at 0 V, and in this state, the first output of feed unit 40 When the terminal OUT1 and the second output terminal OUT2 are connected to the feed conductor, the first output terminal OUT1 and the second output terminal OUT2 both have a voltage of 0 V, and the first detection means 101 and the second detection means 102 have the first detection signal. And do not output the second detection signal. As a result, the logic means 110 outputs a control voltage of 12 V, and this output is sent to the judging means 130 via the delay circuit 120. The delay means 120 delays the control voltage of 12 V and outputs it to the determination means 130. As a result, the determination means 130 initially outputs 0 V from the delay means 120 and the first detection signal of 0 V from the first detection means 101. Although the output of the judging means 130 is 0 V and does not output the driving voltage, the control voltage of 12 V is inputted from the delay means 120 to the judging means 130, and the judging means 130 outputs the driving voltage of 12 V. Do. As a result, the drive coils of the first switch SW1 and the third switch SW3 are excited, the NO contact of the first switch SW1 closes, the NC contact of the third switch SW3 opens, and the positive input terminal IN + becomes the first output terminal OUT1. Connected, the negative input terminal IN- is disconnected from the first output terminal OUT2.

On the other hand, the 0 V output from the second detection means 102 does not excite the drive coils of the second switch SW2 and the fourth switch SW4, and the NO contact of the second switch SW2 is kept open. The NC contact is kept closed and the negative input terminal IN- is connected to the second output terminal OUT2. Therefore, when the feed unit is connected to the feed system for the first time, the positive input terminal IN + is connected to the first output terminal OUT1, and the negative input terminal IN- is connected to the second output terminal OUT2, and the first output The positive terminal 12V of the DC power supply is preferentially applied to the terminal OUT1.

Claims

The scope of the claims

[1] A pole switching circuit for connecting a DC power supply to two feed conductors connected between the DC power supply and the load and connected to the load,

A first output terminal OUT1 connected to one of the two feed conductors;

A first switch SW1 inserted between the positive input terminal and the first output terminal; a second switch SW2 inserted between the positive input terminal and the second output terminal; the negative input terminal; A third switch SW3 inserted between the first output terminal and a fourth switch SW4 inserted between the negative input terminal and the second output terminal;

The first switch SW1 and the fourth switch SW4 conduct when the voltage applied to the first output terminal OUT1 is higher than the voltage applied to the second output terminal, and the positive input terminal IN + The first output terminal OUT1 is connected, and the negative input terminal IN- is connected to the second output terminal OUT2 above.

The second switch SW2 and the third switch SW3 become conductive when the voltage applied to the first output terminal OUT1 is smaller than the voltage applied to the second output terminal OUT2, and the positive input terminal IN + A polarity switching circuit characterized in that it is connected to the first output terminal and to connect the negative input terminal IN- to the second output terminal.

[2] The first switch includes a first switching element having a control end G. The first switching element receives a voltage less than a predetermined value between the control end and the positive input terminal. Conduct,

The second switch includes a second switching element having a control end G, and the second switching element conducts when a voltage less than a predetermined value is applied between the control end and the positive input terminal,

The third switch includes a third switching element having a control end G. The third switching element receives a voltage exceeding a predetermined value between the control end and the positive input terminal. When it

The fourth switch includes a fourth switching element having a control end G. The fourth switching element conducts when a voltage exceeding a predetermined value is applied between the control end and the positive input terminal,

The control end of the first switching element and the control end of the third switching element are both connected to the second output terminal OUT2,

The control end of the second switching element and the control end of the fourth switching element are both connected to the first output terminal OUT1,

The first switch applies a control voltage equal to or greater than the predetermined value of the positive electrode force to the control end of the first switching element and delays the control voltage for a predetermined time to apply a voltage less than the predetermined value to the control end. 1 delay circuit (Rl, C1),

The second switch applies a control voltage equal to or greater than the predetermined value of the positive electrode force to the control end of the second switching element and delays the control voltage for a predetermined time to apply a voltage less than the predetermined value to the control end. Equipped with two delay circuits (R2, C2),

When the voltage applied to the first output terminal is larger than the voltage applied to the second output terminal, the first delay circuit operates and the second delay circuit does not operate.

When the voltage applied to the first output terminal is smaller than the voltage applied to the second output terminal, the second delay circuit operates and the first delay circuit does not operate,

Although the first delay circuit and the second delay circuit operate together when the voltage applied to the first output terminal and the voltage applied to the second output terminal are equal, the second delay circuit operates in conjunction with the second delay circuit. The polarity switching circuit according to claim 1, wherein the delay time by the delay circuit is increased.

The first switching element is an FET having a parasitic capacitance between gate and source, the source is coupled to the positive input terminal, the drain is connected to the first output terminal, and the source voltage is a predetermined value or more than the gate voltage. At the same time, connect the positive input terminal above to the first output terminal above,

The first delay circuit includes the parasitic capacitance C1 and a first resistor R1 inserted in series with the parasitic capacitance between the positive input terminal and the second output terminal. To The connection point with the raw capacity CI is connected to the gate G,

The second switching element is an FET having a parasitic capacitance between the gate and the source, the source is coupled to the positive input terminal, the drain is connected to the second output terminal, and the source voltage is a predetermined value or more than the gate voltage. At the same time, connect the positive input terminal IN + to the second output terminal OUT2,

The second delay circuit (R2, C2) includes the parasitic capacitance C2 and a second resistor R2 inserted between the positive input terminal IN + and the first output terminal OUT1 in series with the parasitic capacitance. The connection point between the second resistor and the parasitic capacitance is connected to the gate G,

The resistance value of the first resistor R1 is smaller than the resistance value of the second resistor R2, and the time constant of the first delay circuit is smaller than the time constant of the second delay circuit. Polarity switching circuit.

[4] A first voltage dividing resistor is connected in series with the first resistor R1 between the positive input terminal IN + and the second output terminal, and between the first resistor R1 and the first voltage dividing resistor R11 The gate of the first switching element is connected to the connection point of

A second voltage dividing resistor is connected in series with the second resistor R2 between the positive input terminal IN + and the first output terminal, and a connection point between the second resistor R2 and the second voltage dividing resistor R21. 4. The polarity switching circuit according to claim 3, wherein the second switching element is connected to the gate of the second switching element.

[5] A first Zener diode is inserted between the first voltage dividing resistor R11 and the positive input terminal IN +,

The polarity switching circuit according to claim 4, wherein a second Zener diode is inserted between the second voltage dividing resistor R21 and the positive input terminal IN +.

[6] A direct current voltage supply unit comprising the polarity switching circuit according to any one of claims 1 to 5 and the above direct current power supply.

[7] The DC power supply is characterized in that it is connected to the AC power supply and configured to convert AC power into DC power, and is provided with a power switch for turning on and off the connection with the AC power supply. The direct current voltage supply unit according to claim 6.