JPH02257744A - Call signal generator for telephone set - Google Patents

Abstract

PURPOSE:To attain high utilizing efficiency of a power supply and to constitute the generator with small size by applying a high frequency signal to a boosting transformer. CONSTITUTION:A high frequency generating circuit 1 outputs a high frequency signal and a control circuit 11 outputs a control signal to a gate 2. While the control signal is set, the high frequency signal drives a switching element 3 to switch a DC power voltage Vcc (DC24-48V) via a boosting transformer 4 thereby generating a high frequency voltage of nearly 75V at the secondary side of the transformer 4. Since the high frequency signal is applied to the boosting transformer 4, high utilizing efficiency of power supply is obtained and the call signal generator with small size for a telephone set is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a ringing signal generating device for a telephone.

(Prior art) Generally, the ringing signal for ringing a telephone bell is 16).
A signal is used in which an alternating current voltage of 12.75 V is repeatedly turned on and off at a constant cycle, for example, turned on for 1 second and turned off for 2 seconds. FIG. 5 is a block diagram showing an example of a conventional calling signal generating device for ringing a telephone bell, and FIG. 6 is a diagram showing waveforms of the main parts of the device.

This conventional example includes a 1611□ oscillation circuit 18 and an amplifier 19.
and a control circuit 21, a relay contact 22 that opens and closes according to a control signal from the control circuit 21, an output transformer 2o that boosts the output of the amplifier 19, and an output terminal 1 that is connected to a telephone or the like.
5 and a ring trip detection circuit 16 that monitors whether or not the output terminal 15 is connected by the DC circuit.

In the conventional example, in order to ring the bell of a telephone connected via the output terminal 15, the control circuit 21 connects the relay contact 2.
2 is driven by the signal shown in FIG. 6(h), the output terminal 1
5, the signal shown in FIG. 6(j) is obtained, and the telephone bell can be rung.

When the handset of the telephone is removed, a self-current circuit is formed, which is detected by the ring trip detection circuit 16 and transmitted to the control circuit 21. The control circuit 21 stops the control signal driving the relay contact 22, thereby stopping the ringing.

[Invention or problem to be solved]

1) In the conventional example η, 16+1. Since the J4 pressure river transformer 20 is used at such a low frequency, there is a problem that the power supply efficiency is poor. In addition, if an attempt is made to reduce the loss of the step-up transformer 20, the shape of the transformer becomes large and expensive materials are used, which increases the cost of the transformer and requires the implementation of an output signal generator. There is a problem that the volume becomes large.

The present invention has been made in order to solve these problems, and an object of the present invention is to provide a telephone ringing system that is highly efficient in power supply use and is compact in size.

[Means for Solving the Problem] In order to achieve objective H in the present invention, a high frequency voltage is applied to a step-up transformer. It consists of

(1) A generating means for generating a high frequency signal, a single stage of rectification for rectifying the high frequency signal generated by the generating means, a switching means for periodically switching the output polarity of the rectifying means, and a switching means for periodically switching the output polarity of the rectifying means; Output means for outputting the output signal of the switched rectifying means to the telephone, detection means for detecting a response from the telephone, and control means for stopping the output from the output means when the detection means detects a response. A telephone ringing signal generator that performs 47 calls.

(Function) By configuring as described in (1) above, the step-up transformer receives a high frequency signal, operates with high efficiency, and can be made compact. When the voltage of the high-frequency signal is sufficiently large, a step-up transformer is not required.

〔Example〕

The present invention will be explained below with reference to Examples.

FIG. 1 is a circuit diagram of a complete telephone call number 48 generator according to an embodiment of the present invention. In the figure, l is 10 to 100
A high frequency generation circuit that constantly outputs a signal with a frequency of about k11□, 2 a gate that cuts off the output signal of the high frequency generation circuit 1, 3 a switching element such as a transistor or FET (field effect transistor), 4 a switching element 3 A step-up transformer is driven by switching and outputs a boosted high-frequency voltage to the secondary side, and 5.6 is a rectifier diode that determines the rectification direction. Phototransistor couplers 7 and 8 select diodes 5 and 6 that determine the rectification direction. R1 is a current limiting resistor that prevents excessive current from flowing through the rectifier diode 5.6 when switching the polarity of the output voltage. 10 smoothes the rectified high frequency voltage with a smoothing capacitor. Ft2. R3 is a current limiting resistor when the output is short-circuited. Further, R4 and R5 are current limiting resistors on the light emitting diode side of the photocoupler 7.8.

The control circuit 11 intermittently supplies the high frequency signal generated by the high frequency generating circuit 1 to the switching element 3 by controlling the gate 2 to turn on and off for 1 second and then off for 2 seconds. Furthermore, the control circuit 11 alternately reverses the rectification direction of the high frequency voltage that has been turned on by controlling the photocoupler 7.8 every 1/32 seconds.

Next, the operation of the 11th embodiment will be explained.

FIG. 2 is a diagram showing signal waveforms of main parts of the circuit diagram shown in FIG. 1, and FIGS. 2(a) to 2(f) are signal waveforms of the portions a to f in FIG. 1.

First, the high frequency generation circuit 1 outputs the high frequency signal shown in FIG. 2(a), and the control circuit 11 outputs the control signal shown in FIG. 2(b) to the gate 2. While this control signal is on,
The above-mentioned high frequency signal drives the switching element 3 and passes through the step-up transformer 4 to the DC power supply voltage Vcc (DC24 to 4
8V) and approximately 75V to the secondary side of transformer 4.
A high frequency voltage (FIG. 2(C)) is generated.

This high frequency voltage of approximately 75V is rectified by the rectifier diode 5 and then passed through the resistor R1 to the smoothing capacitor 10 during the period when the control circuit 11 turns on the converter 7 using the control signal shown in FIG. 2(d). smoothed. Further, during the period when the control circuit 11 or the photocoupler 8 is turned on by the control signal shown in FIG. 2(e), the signal is rectified by the rectifier diode 6 and smoothed by the capacitor 10 via the resistor R1. Here, since the polarities of diode 5 and diode 6 are opposite, an alternating current signal whose polarity changes alternately at a cycle of 1/32 seconds is generated at the output terminal 15, as shown in Fig. 2(f). do. This Shingetsu has a voltage of 5 frequencies, enough to move a telephone bell by 1β. Note that the value of the resistor R1 and the value of the capacitor 10 have values sufficient to rectify and smooth the high frequency voltage. It is also assumed that the resistors R2 and R3 have values that can be ignored to ring the bell of the telephone.

(Application example) A ringing signal generating device as in this embodiment is used in conjunction with a DC supply circuit and a ring trip detection circuit for detecting whether or not a telephone has responded to a ringing signal.

Figure 3 shows an example of its application.

There is an example as shown in Figure 4. Reference numeral 30 denotes a paging (li) generator having the configuration shown in the first figure. When the control circuit 11 detects a response by the ring trip detection circuit 32, it turns off the gate 2 to terminate the sending of the paging signal.

In the case shown in FIG. 3, the ringing signal generator needs to flow direct current during the 2-second period when the bell stops ringing.
In the circuit shown in the figure, it is possible to respond by turning on the photocoupler 8 during the period when the bell is not moving. In addition, in the case shown in FIG. 4, it would be a problem if the calling signal output circuit should not pass DC during the period when the bell is not moving, so in the circuit shown in FIG. can be accommodated.

Further, in this embodiment, a rectifier diode and a phototransistor coupler are used to control the rectification polarity, but other elements such as a photothyristor coupler and FET may be used, and the generation frequency of the high frequency generation circuit , the value of the DC power supply voltage Vcc.

The step-up ratio of the transformer 4 and the frequency of the signal for ringing the bell may be arbitrarily set as necessary. Furthermore, since these frequencies are controlled by the control circuit 11, it is easy to make them variable.

In addition, in the circuit shown in FIG. 1 of this embodiment, 1 of the step-up transformer 4 is
On the next side, intermittent operation is carried out for 1 second on and 2 seconds off, but the primary side of the step-up transformer 4 is operated continuously, and the photocoupler 7.8 performs intermittent operation Even with this configuration, the same operation and effect as the device shown in FIG. 1 can be expected.

〔Effect of the invention〕

As described above, according to the present invention, since a high frequency signal is applied to the step-up transformer, the efficiency of use of the power source is high and the device can be configured to be compact. Note that if the voltage of the high-frequency signal is sufficiently large, a step-up transformer is not required.
Can be made smaller.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of an embodiment of the present invention, Figure 2 is a waveform diagram of essential parts of the same embodiment, Figures 3 and 4 are configuration diagrams of an application example, and Figure 5
The figure is a configuration diagram of a conventional example, and FIG. 6 is a waveform diagram of essential parts of the conventional example. 3... Switching element 4... Step-up transformer 5.6... Rectifier diode

Claims (1)

[Claims] (1) A generating means for generating a high frequency signal, a rectifying means for rectifying the high frequency signal generated by the generating means, a switching means for periodically switching the output polarity of the rectifying means, and switching of the output polarity by the switching means. the output means for outputting the output signal of the rectifying means to the telephone; a detection means for detecting a response from the telephone; and a control means for stopping the output from the output means when the detection means detects a response. A telephone ringing signal generator characterized by: