JPH0444876B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a C position circuit in the trunk of an exchange.

(Background Art) Conventionally, the logic of the trunk C position circuit has been implemented using relay contacts, and as shown in the circuit diagram of Fig. 1 and the operation time chart of Fig. 4,
A relay for dialing, B relay that operates when the A relay is activated and connects the slow recovery circuit with its self-contact to perform a slow recovery, and a B relay that operates only when the B relay is activated by the recovery of the A relay and uses its self-contact. It consists of a C relay that connects a slow recovery circuit to perform a slow recovery, and when the A relay is operating, the B
When only the relay operates and dial pulses are sent by turning on and off the A relay, both the B and C relays operate, and the contacts of the C relay eliminate the distortion of the dial pulse caused by the capacitor in the communication circuit. It works to prevent. At this time, the C relay operates while the A relay is sending pulses, continues to operate during the rest time between pulse trains, and when the pulse sending ends, the
It will be restored when the relay is restored and the B relay is restored. Slow recovery of both the B relay and C relay was performed by a slow recovery circuit using a capacitor.

However, in such conventional C position circuits, the logic is carried out through relay contacts, so a multi-contact relay is required, and the slow recovery circuit also requires a large capacity and large capacitor.
The disadvantages were that the price and shape were large.

(Problems to be solved by the invention) An object of the present invention is to solve the above-mentioned drawbacks, and furthermore, it is an object of the present invention to reduce the power consumption of driving a C relay, and to reduce the power consumption of a miniature relay (having two or one contact). The objective is to obtain a C position circuit using a small consumer relay.

(Structure and operation of the invention) The main point of the present invention is that in the C position circuit of the trunk circuit, an A relay drive circuit for dial sending, a signal obtained by delaying the A relay drive signal with a first capacitor, and a preset potential The B relay drive circuit is connected to the output of the first detection circuit using a comparator that compares the B relay drive circuit, and the output of the A relay drive circuit is delayed by a second capacitor and connected to one input terminal, and The output of the relay drive circuit is delayed by a third capacitor and connected to the other input terminal, and the magnitude relationship between the voltage at the one input terminal and the voltage at the other input terminal, which fluctuates during dial transmission of the A relay. and a second detection circuit using a comparator configured to maintain the voltage of the second input terminal, and the second detection circuit detects that the magnitude relationship between the voltage at one input terminal and the voltage at the other input terminal is different. The purpose is to drive the C relay by the output.

FIG. 2 is a circuit diagram showing an embodiment of the present invention, in which the base of the A relay driving transistor Q0 is connected to the switch SW through a resistor R2.
Switch SW has diode D0 and resistor R3 at the same time.
The positive input of the comparator CM0 is connected to the ground through the resistor R4 and the capacitor CC2.
The negative input of the comparator CM0 is connected to the power supply E through a resistor R5 and grounded through a resistor R6. Also, the base of the B relay drive transistor Q1 is connected to a comparator through a resistor R8.
Connected to the output of CM0.

On the other hand, the base of the C relay driving transistor Q2 is connected to the output of the comparator CM1 through a resistor R12, and the positive input of the comparator CM1 is connected to the collector of the transistor Q0 through a diode D1 and a resistor R7, and at the same time, a resistor R11 and a capacitor CC4. is grounded by The negative input of the comparator CM1 is connected to the collector of the transistor Q1 through a resistor R9, and simultaneously connected to the power supply E through a resistor R10 and grounded through a capacitor CC3.

Next, to explain the operation, first, when the switch SW is turned on, the transistor Q0 is turned on, and furthermore, the positive input of the comparator CM0 exceeds the negative input, and the comparator CM0 is connected to the resistor R8.
Since the base current of transistor Q1 is output through the transistor Q1, the transistor Q1 is also turned on, and the A relay and B relay operate. At this time, the comparator CM
Initially, capacitor CC3 is charged to the power supply voltage by resistor R10 and that voltage is applied to the negative input of No.1, but when transistor Q1 is turned on, it is discharged through the route of resistor R9 - transistor Q1 - earth, and the power supply voltage At the same time, the positive input also changes as the transistor Q0 turns on, causing the diode D1 to change.
is reverse biased, and capacitor CC4 is connected to resistor R
11, it becomes the ground level,
As shown in Figure 3, by making the discharge speeds of capacitors CC3 and CC4 the same, the negative input will not be exceeded and comparator CM1 will not detect any change, so transistor Q2 will not turn on and C relay will not operate.

Next, turn the switch SW OFF → ON → OFF → ON...
When the dial pulse is sent out by changing the
While the switch SW is OFF, the positive input of the comparator CM0 drops as the capacitor CC2 is discharged by the resistor R4, but when the switch SW
Since the OFF time is short, it does not fall below the negative input of comparator CM0, and transistor Q
1 is turned on and the B relay continues to operate. As a result, the negative input of comparator CM1, which is the comparison voltage, is the switch SW by sending dial pulses.
It is not affected by the change from OFF to ON. On the other hand, the positive input of comparator CM1 is
Regarding the charging voltage of the capacitor CC4, when the transistor Q0 is turned off, that is, the A relay is restored, the diode D1 is turned on, and the capacitor CC4 is rapidly charged through the resistor R7. The charging voltage of capacitor CC4 determined by resistor R7 and resistor R11 exceeds the negative input of comparator CM1, transistor Q2 is supplied with base current by comparator CM1 and turned on, and C relay operates. . Next is the switch SW
During the ON time, the capacitor CC4 is discharged by the resistor R11, but since the ON time of this switch SW is short, by appropriately selecting the values of the resistor R11 and the capacitor CC4, the positive input of the comparator CM1 can be set to the comparison voltage. Since the voltage does not become lower than the negative input, transistor Q2 turns on and the C relay continues to operate. Therefore, while the A relay is sending out dial pulses, it is possible to create a C position circuit that operates the B relay and the C relay. During the rest time between pulse trains, the switch SW is
When ON, A relay operates and comparator CM0
Since the positive input of is higher than the negative input of
Transistor Q1 turns on and B relay operates, but the positive input of comparator CM1 becomes lower than the negative input, turning off transistor Q2 and restoring C relay. As a result, the C relay is operated only while dial pulses are being sent.

Figure 3 is a time chart showing the operation of each part in Figure 2.From the top, the operation of the switch SW, the collector of transistor Q0, the input of comparator CM0, the collector of transistor Q1, the comparator
The input of CM1 and the collector of transistor Q2 are shown, respectively.

(Effects of the Invention) As explained above, the present invention has a first detection circuit that inputs an A relay drive signal, a B relay drive circuit, and a second detection circuit that changes a comparison voltage according to the output of the B relay drive circuit. A detection circuit is provided to monitor the A relay drive signal, and a circuit is provided to drive the C relay using the output of the second detection circuit, so an inexpensive miniature relay with a small number of contacts can be used. , the size can be made smaller, and the slow recovery of the B and C relays is controlled by a comparison section made up of an electronic circuit, instead of being configured with a self-holding circuit using a capacitor, as in the past, so it can be used as a self-holding circuit. This invention eliminates the need for large capacitors with large capacitances, and saves power by using small capacitors. Even if miniature relays are used, dial pulse transmission only requires on/off control of A relays, and C It has the advantage of not requiring program control such as relay state control, and can send dial pulses without distortion.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional C position circuit, FIG. 2 is a circuit diagram of an embodiment of the present invention, FIG. 3 is a time chart showing the operation of each part of FIG. 2 is a time chart showing the operation of each part of FIG. 1.

Claims (1)

[Scope of Claims] 1. In the C position circuit of the trunk circuit, A relay drive circuit for dial sending and a comparison of a signal obtained by delaying the A relay drive signal with a first capacitor and a preset potential. The B relay drive circuit is connected to the output of the first detection circuit using the device, and the output of the A relay drive circuit is delayed by a second capacitor and connected to one input terminal, and the output of the B relay drive circuit is is delayed by a third capacitor and connected to the other input terminal, and the voltage at the one input terminal fluctuates during dial transmission of the A relay;
and a second detection circuit using a comparator that maintains a magnitude relationship with the voltage of the other input terminal, and the magnitude relationship between the voltage of one input terminal and the voltage of the other input terminal is different. A C position circuit for a trunk circuit, characterized in that a C relay is driven by an output of a second detection circuit that detects this.