JPH01248733A - Tone ringer circuit for telephone set - Google Patents

Abstract

PURPOSE:To reduce the chip area in case of circuit integration and to decrease the number components due to elimination of use of a speaker and a capacitor or the like by providing a hook switch and a resistor for positive feedback and operating a reception amplifier as an oscillator with the arrival of a call to use the circuit with a tone ringer circuit in common. CONSTITUTION:An oscillator is constituted by connecting one terminal of the resistor R6 for positive feedback to the output of an amplifier 3 and connecting the other terminal to a noninverting input terminal of a reception DC amplifier via a hook switch HS2. A call signal is smoothed by a capacitor C2 via a capacitor C1, a resistor R1, a diode bridge 1 and a constant current source 2 to be a power supply for the DC amplifier 3, the oscillator is oscillated at a frequency depending on resistors R2, R4 and R5 and a capacitor C3 to ring a receiver R. On the other hand, the hook switch HS1 is closed and the HS 2 is opened at the time of talking, the resistor R6 for positive feedback is disconnected and the amplifier acts like a reception amplifier.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tone ringer circuit for a telephone set, and to its circuit configuration.

[Conventional technology]

Conventionally, a tone ringer circuit for a telephone set is configured as shown in FIG. 3, and is provided with a tone ringer circuit 4 including an oscillator and a speaker drive circuit in addition to a direct current amplifier 3 for reception, and when a call is received from the telephone set, a ringing signal is transmitted to a capacitor C1. diode bridge 1 and hook switch H via resistor R1
It is rectified and smoothed by the capacitor C4 through the power source 83, and the tone ringer circuit 4 operates using it as a power source to output the speaker SP.
It was ringing.

[Problem to be solved by the invention]

The conventional tone ringer circuit for telephones described above has a circuit independent of the receiving DC amplifier, which increases the chip area when integrated and requires a transfer contact to switch the power supply to the receiving DC amplifier and the tone ringer circuit. The disadvantage is that it requires a hook switch, a smoothing capacitor C4, a speaker, etc., and requires a large number of parts.

[Means to solve the problem]

The tone ringer circuit for a telephone according to the present invention is equipped with a positive feedback resistor and a 1-meter hook switch in a direct current amplifier for receiving a call, and is configured to provide positive feedback to the positive input terminal of the amplifier for receiving a call when a call is received, and to cause the receiver to ring as an oscillator. Ru. That is, in the present invention, the receiving direct current amplifier is operated as a transmitting circuit when a call is received, and is also used as a tone ringer circuit, thereby reducing the chip area when integrating the hook switch, the speaker, and the smoothing capacitor 04 having transfer contacts. etc. become unnecessary.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows a circuit configuration of an embodiment of the present invention.

Hook switches H8I and H82 indicate the state of the telephone when a call is received; one end of the positive feedback resistor R6 is connected to the output of amplifier 3, which operates as an amplifier for receiving calls during a call, and the other end is connected to the hook switch. H82 is connected to the positive input terminal of the receiving direct current amplifier and configured as an oscillator. The call signal is smoothed by the capacitor C2 via the capacitor CI, the resistor R1, the diode bridge and the constant current source, and becomes the power source for the DC amplifier 3, and the resistor R2゜R4.
, R5 and the capacitor C3 to cause the receiver ■ to ring. On the other hand, during a call, the hook switch H8I serves as a meter, H82 serves as a break, and the positive feedback resistor R6 is disconnected, creating a circuit that is exactly the same as the receiver amplifier shown in FIG. At this time, the DC power is supplied to the amplifier 3 via the hook switch H8I, the diode preamp, the diode 1, and the constant current source 2, and the receiving signal superimposed on the DC is the connection point between the sidetone balancing circuit BN and the resistors R4 and R5. The signal is then input to the negative input terminal of the amplifier 3 via the capacitor C3, and becomes an inverting amplifier, which operates as a receiver amplifier.

FIG. 2 shows another embodiment of the invention. In this embodiment, the constant current source 2 is on the one power supply side, and the AC ground is on the tenth power supply side. Therefore, the receiver and the sidetone balancing circuit BN and the resistor R4,
R5 is arranged opposite to the embodiment of FIG. When the direct current amplifier 3 for receiving a call is called, the positive feedback resistor R6 is connected to the positive input terminal of the amplifier 3 by a hook switch H82 to function as an oscillator, and the operation thereof is the same as that of the embodiment shown in FIG.

〔Effect of the invention〕

As explained above, the present invention is equipped with a one-make hook switch and a positive feedback resistor, and the receiving amplifier operates as an oscillator when receiving a call and is shared with the tone ringer circuit, thereby reducing the chip area in the case of integration. This also has the effect of reducing the number of parts by eliminating speakers, capacitors, etc.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a circuit diagram of another embodiment of the invention, and FIG. 3 is a circuit diagram of a conventional tone ringer circuit for a telephone. 1...Diode bridge, 2...Constant current source, 3...DC receiver amplifier, 4...
・Tone ringer circuit, H8I, H82, H83...
...hook switch, ■ ... telephone receiver, [phase]
...Speaker, BN...Sidetone balance circuit, C1-C4...Capacitor, R1 to R6...
group/resistor. Agent Patent Attorney Uchihara Otoatsu 1st 4F-Nrineraton≦, Figure 5

Claims (1)

[Claims] It includes a direct current amplifier for receiving, a receiver, a positive feedback resistor, and first and second hook switches, and the second hook switch connects the positive feedback resistor to the positive input terminal of the direct current amplifier for receiving. A tone ringer circuit for a telephone set, characterized in that the tone ringer circuit is connected to form an oscillator, thereby causing the receiver to ring.