JPS5937620B2 - Carrier wave current source switching circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a carrier wave current source switching circuit used in a carrier device or the like.

An example of a conventional carrier wave current source switching circuit is shown in FIG.

In FIG. 1, N is the first carrier current generation circuit, E is the second carrier current generation circuit, 1 is the first carrier current source, 2 is the first level detection circuit, 3 is the control relay, and 4 is the Contacts of control relay 3, 5 is first switching relay, 6, 12 are capacitors, T, 13 are resistors, 8, 14 are pseudo loads, 9 is contact of relay 5, 10 is second carrier wave current source, 11 is the second switching relay, 15 is the contact of relay 11, 16 is the output terminal,
17 and 18 are power supply terminals. In FIG. 1, when the first carrier wave current source 1 is normal, the control relay 3 is operated by the level detection circuit 2, the contact 4 of this relay is in the state shown by the solid line, and the first switching relay 5 No current flows through the contact 9, which is inactive and the contact 9 is in the state shown by the solid line.

In addition, current flows through the second switching relay 11 and it is operating, and its contact 15 is in the state shown by the solid line. Therefore, the first
An output current from the carrier wave current source 1 is sent to the output terminal 16. Next, if carrier wave current source 1 becomes a failure,
An output fault is detected by the relay detection circuit 2, and the control relay 3
is restored, its contact 4 is in the state shown by the broken line, the second switching relay 11 is restored, its contact 15 is in the state shown by the broken line, and the first switching relay 5 is activated, and its contact 9 is in the state shown by the broken line. The state shown is as follows.

The first carrier current source 1 is therefore terminated to a pseudo load 8,
The output current from the second carrier current source 10 is output to the output terminal 16.
will be sent to. The capacitor 12 and the resistor 13 are used to slowly restore the second switching relay 11, which is caused by the chatter of the contact 4 of the control relay 3 and the switching relays 5 and
Due to the difference in the operation and recovery time of the first switching relay 5, the second switching relay 11 is operated before the first switching relay 5, and the outputs from the first and second carrier wave current sources 1 and 10 are This is to prevent currents from being sent to the output terminals 16 at the same time. Incidentally, the capacitor 6 and the resistor 7 do not act when the first switching relay 5 is operated, and the switching relay 5 operates quickly. When the fault in the first carrier wave current source 1 is recovered, the control relay 3 is activated by the level detection circuit 2, its contact 4 returns to the state shown by the solid line, the first switching relay 5 is restored, and the second The switching relay 11 operates.

The contacts 9 and 15 of both relays return to the state shown by the solid line,
The output current of the second carrier current source 10 is terminated to the pseudo load 14, and the output current from the first carrier current source 1 is sent to the output terminal 16. In this case as well, the first carrier current source 1
For the same reason as when switching from to the second carrier wave current source 10, the second switching relay 11 operates quickly, and the first switching relay 5 operates slowly due to the action of the capacitor 6 and resistor 7.
In the conventional circuit described above, in order to prevent the output currents from the first and second carrier wave current sources 1 and 10 from being simultaneously sent to the output terminal 16, the first and second switching relays 5,
Capacitor, resistor 6, 7, 12, 1 in parallel with winding 11
By connecting 3 as shown in the figure, the relays 5 and 11
We are trying to achieve a fast-paced recovery.

In the case of this method, the recovery time changes depending on the variation in the open current of the relay, so it is necessary to adjust the values of the resistor and capacitor at the manufacturing stage. In addition, since fluctuations in the power supply voltage directly result in changes in the recovery time, the first and second carrier current sources 1,
In order to prevent output currents from output terminals 10 from being simultaneously sent out from output terminals 16, it is necessary to lengthen the recovery time of switching relays 5 and 11 for safety reasons, and the switching time will inevitably become longer. In other words, the momentary interruption time becomes longer. Furthermore, it is necessary to use a control relay 3 that is high speed and has little chatter, and there are restrictions on the selection of the relay. In order to solve these drawbacks, the present invention uses an inverting circuit to drive the switching relay,
This is a carrier wave current source switching circuit configured using a switching relay drive circuit having fast-acting-slow recovery characteristics, and will be described in detail below.

FIG. 2 shows an embodiment of the present invention, in which N is a first carrier current generation circuit, E is a second carrier current generation circuit, 100 is a first carrier current source, 101 is a level detection circuit, and 102 is a first carrier current generation circuit.
103 is a first switching relay drive circuit having fast-acting and slow recovery characteristics; 104 is a first switching relay; 105 is an inverting circuit;
is a contact of the switching relay 104, 106 and 111 are pseudo loads, 1 m is a second carrier wave current source, 108 is a second switching relay drive circuit having fast-acting and slow recovery characteristics, 109 is a second switching relay, and 110 is a Contact points of the switching relay 109, 112 are output terminals, and 113 and 114 are power terminals. In FIG. 2, when the first carrier current source 100 is normal, the first switching relay 104 is in the non-operating state, and the second switching relay 10
9 is an inverting circuit 102 and a switching relay so as to be in an operating state.
The drive circuits 103 and 108 are set, the contact 105 of the first switching relay 104 is connected to the output terminal 112 side as shown by the solid line, and the contact 110 of the second switching relay 109 is connected to the pseudo terminal as shown by the solid line. It is connected to the load 111 side.

The output current of the first carrier current source 100 is therefore delivered to the output terminal 112. When the first carrier wave current source 100 becomes a failure, the output detected by the level detection circuit 101 causes the inversion circuit 102 and the first switching relay drive circuit 103 having fast-acting-slow recovery characteristics to reverse the above state. The state will be as follows. That is, the first switching relay drive circuit 1
03 receives the output of the level detection circuit 101 and immediately operates the first switching relay 104, its contact 105 is in the state shown by the broken line, and the output current of the first carrier wave current source 100 is terminated to the pseudo load 106. . On the other hand, the output of the level detection circuit 101 is also given to an inversion circuit 102, and its output is given to a second switching relay drive circuit 108. Second
The switching relay 109 is in an operating state when the first carrier wave current source 100 is normal, but the output of the second switching relay drive circuit 108 is inverted by the output of the inverting circuit 102, and the second switching relay 109 is in an operating state. Recover. The second switching relay drive circuit 108 has a delay characteristic, that is, a slow recovery characteristic for the recovery of the second switching relay 109, and the second switching relay 109 recovers slowly. Therefore, after the contact 105 of the first switching relay 104 operates and enters the state shown by the broken line, the contact 110 of the second switching relay 109 recovers and enters the state shown by the broken line, and the second carrier wave current source 107 output current will be sent to the output terminal 112, and the first
, the second output currents are not delivered to the output terminal 112 at the same time. When the first carrier wave current source 100 returns to normal, the output of the level detection circuit 101 returns to the original state, and the first,
The outputs of the second switching relay drive circuits 103 and 108 are inverted, the first and second switching relays 104 and 109 return to their original states, and the contacts 105 and 110 return to their solid line states. In this case as well, since the first switching relay drive circuit 103 has a slow recovery characteristic, the contact 11 of the second switching relay 109
0 becomes the state shown by the solid line, the first switching relay 1
04 contact 105 is restored to the state shown by the solid line, the output current of the first carrier wave current source 100 is sent to the output terminal 112, and the first and second output currents are simultaneously sent to the output terminal 11.
It is never sent from 2. Next, a switching relay drive circuit with quick action and slow recovery characteristics will be explained.

Figure 3 shows the first and second switching relays in Figure 2 → rotation circuit 10
3,108 is a detailed diagram. In Figure 3, D1 is a diode, Rl, R2, R3 are resistors, C1 is a capacitor,
ICl is the level detection circuit 101 or inversion circuit 102 in FIG. output circuit, IC2 is an operational amplifier, R
Ll is the switching relay 104 or 109 in FIG.
The relay corresponding to , 150 is the input terminal of this circuit, 151
is the power supply terminal, 152 is the output terminal of this circuit, VIN is the voltage of the input terminal 150, V+ is the non-inverting input terminal voltage of operational amplifier C2, V- is the inverting input terminal voltage of operational amplifier 1C2, and VOUT is the operational amplifier 1C2. The output voltage of , e indicates the power supply voltage. The input voltage IN of this circuit is the ground voltage or power supply voltage, and changes in a stepwise manner when the carrier wave current source fails or the failure is recovered.

If the human power voltage VIN changes from the power supply voltage to the earth voltage,
The inverted input voltage V- is applied to a diode D connected in parallel to the resistor R1 of an integrating circuit consisting of a resistor R1 and a capacitor C1, and in a forward direction from the input terminal to the operational amplifier.
The operational amplifier 1 changes according to the time constant ClRF determined by the forward resistance RF of 1 and the capacitor C1, and exceeds the non-inverting input voltage + set by the resistors R2 and R3.
The output voltage 0UT of C2 changes stepwise from the ground voltage to the power supply voltage. Furthermore, when the input voltage IN changes from the ground voltage to the power supply voltage, the inverted input voltage V- changes according to the time constant ClRl determined by the resistor R1 and the capacitor C1, since the reverse resistance of the diode D1 is sufficiently large and can be ignored. However, when the non-inverting input voltage V+ is exceeded, the output voltage VOu of the operational amplifier 1C2? It changes from the power supply voltage to the earth voltage in steps. Therefore, the time from when the input voltage VIN changes stepwise until the output voltage VOUT changes stepwise is the same when the input voltage VIN changes from the power supply voltage to the ground voltage and when it changes from the ground voltage to the power supply voltage. So, the time constant C
They differ by the difference between lRF and ClRl. For example, resistor R2 so that the non-inverting input voltage V+ becomes % of the power supply voltage e
, R, when the input voltage VIN changes stepwise from the power supply voltage e to the earth, the time it takes for the inverted input voltage 1 to reach e/2 from the power supply voltage is ClRFl, as is well known.
Og82, and the input voltage VIN is from the earth to the power supply voltage e
The time it takes for the inverted input voltage - to reach e/2 from ground level is ClRllOg82.

This time relationship does not change even if the power supply voltage e changes. That is, as mentioned above, the input voltage IN is the earth's voltage or the power supply voltage e.
, and since the non-inverting input voltage + is divided by resistors R2 and R3 so that it becomes % of the power supply voltage e, the power supply voltage e
Even if the voltage changes, the voltage is e/2. Therefore, the time required for the inverted human power voltage V- to reach e/2 from the ground voltage or the power supply voltage e is still ClRllOg82 and ClRFlOg82, and is not affected by fluctuations in the power supply voltage. Therefore, unlike the example of the conventional circuit shown in FIG. 1, there is no need to make the slow recovery time of the switching relay longer than necessary. In addition, in the conventional relay drive circuit, when trying to obtain a slow recovery characteristic, the diode D1 in Fig. 3 was not provided, so the resistor R1 of the integrating circuit was also used during operation.
, it had a slow operating characteristic due to the action of capacitor C1, but
If the diode D1 is connected in parallel with the resistor R1 as shown in FIG. By choosing this value, the operating time ClRFlmg82 is extremely small and the recovery time ClR
It is easy to increase llOgO2, and the first and second switching relays 104 and 109 in FIG. 2 can be quickly and slowly restored in a stable manner regardless of power supply voltage fluctuations and so that the restoration time does not become longer than necessary. I can do it. Furthermore, unlike the conventional circuit shown in FIG. 1, since the control relay 3 is not provided, there is no need to consider preventing chatter of the contacts of the relay. As explained above, according to the present invention, when switching between the first and second carrier current sources, the switching time can be shortened by using a switching relay drive circuit having an inverting circuit and a fast-acting-slow recovery characteristic. A stable switching circuit that is not affected by voltage fluctuations can be provided at low cost.

The switching circuit according to the present invention, which has such advantages, can be applied not only to conveyance devices but also, for example, to regular standby switching circuits for traffic lights.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional carrier wave current source switching circuit, FIG. 2 is a block diagram of an embodiment of the present invention, and FIG. 3 is a circuit diagram of a switching relay drive circuit used in an embodiment of the present invention. N is the first carrier current generation circuit, E is the second carrier current generation circuit, 1,100 is the first carrier current source, 2,101
is a level detector, 3 is a control relay 4 is a contact of control relay 3, 5, 104 is a first switching relay, 6, 12 is a capacitor, 7, 13 is a resistor, 8, 14, 106, 111 is a pseudo load, 9,105 is a contact of the first switching relay 5,104, 10,107 is a second carrier wave current source, 11,109
is the second switching relay, 15, 110 is the contact of the second switching relay 11, 109, 16, 112 is the output terminal, 102
103 is an inverting circuit, 103 is a first switching relay drive circuit, and 10
8 is a second switching relay drive circuit, 17, 18, 113,
114 is a power supply terminal, 150 is an input terminal, 151 is a power supply terminal, 152 is an output terminal, ICl is an inverting circuit or an output circuit of a level detector, IC2 is an operational amplifier, D1 is a diode, Rl, R2, R3 are resistors, RLl is the switching relay C1 is the capacitor, VIN is the input voltage of the input terminal 150, + is the non-inverting input voltage of the operational amplifier 1C2, - is the inverted human input voltage of the operational amplifier 1C2, 0UT is the operational amplifier 1C2
The output voltage of , e indicates the power supply voltage.

Claims (1)

[Claims] 1. A carrier current is normally supplied to the load from a first carrier current source, and when the output level of the first carrier current source is abnormal, a carrier current is supplied from a second carrier current source. In a carrier wave current source switching circuit of a carrier device, etc., which supplies
Bringing the first switching relay into a recovery state with the output of a first switching relay drive circuit having a quick-slow recovery characteristic that receives the output of the level detection circuit when the output level of the first carrier current source is normal; The second switching relay is activated by the output of the second switching relay drive circuit having fast-acting and slow recovery characteristics, which receives the output of the inversion circuit based on the output of the level detection circuit during normal operation, and the first carrier wave current source is activated. The output level of the first switching relay is activated by the output of the first switching relay drive circuit that receives the output of the level detection circuit when the output level is abnormal, and the output of the inverting circuit is caused by the output of the level detection circuit when the output level is abnormal. The second switching relay is put into a recovery state by the output of the second switching relay drive circuit that receives the signal, and the contact of the first switching relay is interposed between the first carrier wave current source and the load, and the second switching relay is A carrier wave current source switching circuit characterized in that a contact point of a switching relay is arranged between a second carrier wave current source and a load. 2. The switching relay drive circuit has a circuit configuration in which the input voltage is applied to an operational amplifier via an integrating circuit, and the switching relay is driven by the output voltage of the operational amplifier, and in the integrating circuit consisting of a resistor and a capacitor, the input voltage is applied in parallel to the resistor. 2. The carrier wave current source switching circuit according to claim 1, wherein a diode is connected in a forward direction from the input terminal to the operational amplifier to provide a fast-acting-slow recovery characteristic.