JPS58107757A - Ringer power supply circuit for telephone set - Google Patents

Abstract

PURPOSE:To obtain a small-sized ringer power supply suitable for a subscriber terminal, by boosting a high-frequency power supply and switching this rectified voltage at a ringer frequency. CONSTITUTION:A comparator 5 is blocking-oscillated at a frequency determined with a comparison voltage at a noninverting terminal 6, a capacitor C1 and a resistor R1. Comparators 15, 16 are similarly blocking oscillators, and the comparator 15 is used for the ringer frequency and the comparator 16 interrupts the ringer frequency at a prescribed frequency. The output of the comparator 15 controls a switching circuit 14 to shape the ringer frequency. Thus, the more the frequency is increased, the better power transmission rate of a transformer has, thus the ringer power supply circuit can be made small in size by using a suitable high-frequency power transformer 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a miniaturized telephone ringer power supply circuit for subscriber terminals.

(2) Background of technology Since the 11th floor, since ringer electric images for telephones are installed at telephone offices or subscriber terminals, their electrical characteristics have been improved and they have been made smaller. Further miniaturization of power supply circuits is required.

Conventionally, a circuit configuration has been used as a y power supply circuit that amplifies the ringer frequency (f=16 Hz in Zaiban) and boosts the power to a predetermined value using a transformer.

Among these, the transformer is used in 16flZ, so it is considerably larger than other electronic circuits, and it also generates heat, making the power supply circuit large.

Therefore, there has been a demand for a smaller and lighter ringer power supply circuit for subscriber terminals.

(3) Conventional technology and highlights FIG. 1 is a block diagram of a conventional Ringer power supply.

In the figure, the output of a ringer frequency oscillator 1 is amplified by a power amplifier 2, boosted to a predetermined voltage by a power transformer 3, and output from an output terminal 4.

Originally, the efficiency of power transformers decreases when used at low power waves. On the other hand, if the frequency is increased, the cross-sectional area of the core can be reduced and the transformer can be made smaller, but it is difficult to make the transformer smaller when a ringer frequency of 16H2 is used.

(4) Purpose of the Invention In view of the above-mentioned conventional problems, the present invention provides a system in which the Ryoan wave power source is boosted by a high-frequency electrocadrance, rectified, and the rectified i'm voltage is switched at the ringer frequency. The purpose is to provide a compact ringer power supply suitable for subscriber terminals.

(5) Structure and object of the invention According to the present invention, the high frequency oscillator output is boosted by a high frequency transformer, the output of the transformer is rectified by a rectifier, and the cough rectifier output is switched at the ringer frequency and linker period. achieved.

(6) Embodiment of the Invention The present invention will be described below with reference to the embodiment shown in FIG. 2 and the time chart shown in FIG.

In the 21st box, is comparator 5 a condenser? C.

Blocking oscillation is performed at a frequency determined by the resistor R and the comparison voltage Vref% at the non-inverting terminal 6. That is, when a negative power supply ←) is applied, capacitor C1
The charging characteristics of the capacitor CI are determined by Cl5R1, and when the charging voltage exceeds the comparison voltage Vref, the output voltage of the comparator 5 becomes the negative power supply voltage -EK, which causes the capacitor CI to be charged. Comparator 5
The output voltage becomes the ground potential, that is, the E potential. Here, the comparison voltages fEVr@fl and Vref2 are obtained by dividing the output voltage of the comparator 50 by resistors R, , R, and K.

The above blocking oscillation state is described from Fig. 3(a) K, and in Fig. 3, the charging characteristic (I) of capacitor C10 is R1.
When the charging voltage exceeds the comparison voltage R1 Vref1w & X, the output voltage of the comparator 5 becomes -E. discharge by.

The discharge voltage is the comparison voltage Vr e f 2-Ex-j! −
! -R*+Rs, the output voltage of the comparator 5 becomes E.
The period from the start of discharging q to the start of next charging r is also tI. After that, the charging and discharging of the lower capacitor CI is repeated, and the oscillation frequency! '+='- is obtained.

Lr In this case, f is a high frequency of several KH2 or more.

The frequency f obtained as above, tli) is amplified by the Rungis I8, boosted to a predetermined voltage by the high-frequency electrocadrance 9, full-wave rectified by the rectifying element 10, 11, and the capacitor 12.
It is smoothed and becomes a direct current. The switching of the direct current is controlled by a 16H2 switching control circuit 14, and a ringer frequency of 16H2 with a peak value of about 70V shown in FIG.

Operation of comparators 15 and 16 is a blocking oscillator based on the same principle as comparator 5, and comparator 1
5 is for ringer frequency (f=16H, time constant C1・R
This outputs the waveform shown in FIG. 3 according to the comparison voltage Vrsf determined by 1 and the resistor R-1R.

The comparator 16 intermittents the ringer frequency at a constant cycle, for example, the ringer cycle is 1 second and the ringer stop cycle is 2 seconds. This period is determined by comparator 1 as above.
A comparison voltage of 6 is created with a division ratio of Re, R+a, and Cs, R? When , a 1-second ringer cycle is created with 9 numbers, and a 2-second ringer cycle is created with a time constant of Cm・(R, Toshima). At this time, diode D6 is resistor R1
Weld.

Both the ringer frequency f=16 Hz and the ringer period (period of 1 second/2 seconds) obtained as described above control the comparator 5.

The oscillation frequency f = 16H2 of the comparator 15 controls the comparison voltage of the comparator 5 through the diode D2, and switches the output of the comparator 5 at 16Hz. ) controls the switching of both the outputs of the comparators 5 and 15 via diodes D3 and D5, and shapes the waveform shown in FIG. The waveform is amplified by the transistor 8, boosted to a predetermined value by the high frequency capacitor, and rectified by the rectifiers io and xi.
The output is smoothed by a capacitor 12.

On the other hand, the output of the comparator 15 is input to the transistor 17 of the 16 Hz switching circuit 14, which controls the transistors 17 and 18 to perform switching at 1612.

The output of the rectifier is switched by the output of the control l1ol path 14 to shape the ringer frequency of m3 diagram (■).

Here, we will discuss the miniaturization of the transformer.

If the core material of the transformer and the number of windings are constant, the power transfer rate of the transformer improves as the magnetic permeability is placed above the frequency within a certain range.

Therefore, the ringer power supply circuit can be downsized by using an appropriate high frequency quadrance.

(7) Effects of the Invention According to the present invention, since the high frequency power source is boosted by the high frequency room quadrance and used, the transformer can be downsized by an amount corresponding to the frequency increase ratio, and this makes it possible to reduce the size of the transformer by an amount corresponding to the frequency increase ratio. can be made smaller.

[Brief explanation of the drawing]

Fig. 1 shows a conventional ringer power supply circuit, Fig. 2 shows an embodiment of the present invention, and Fig. 3 shows its time chart. In the figure, 1 is a ringer frequency oscillator, 2 is a power amplifier, and 3 is a power transformer. , 4.13 is an output terminal, 5.17.18 is a transistor, 9 is a high frequency chamber cadence, 10.11
#'i diode 12 is a capacitor, and 14 is a switching control circuit.

Claims (1)

[Claims] A ringer power supply circuit for a telephone set, characterized in that the output of a high frequency oscillator is boosted by a transformer, the output of the transformer is rectified by a rectifier, and the output of one rectifier is switched at the ringer frequency and ringer period.