JPS62227256A - Subscriber circuit - Google Patents

Abstract

PURPOSE:To make a subscriber circuit main body into an LSI at low cost by a PN junction separating process, by supplying a substrate voltage after performing the double voltage commutation of the output of a call sound source, and suppressing a signal voltage supplied from the call sound source to the subscriber circuit main body so as not to exceed the substrate voltage by a protection circuit. CONSTITUTION:A double voltage commutation circuit E connected to a call sound source B is constituted of two diodes D1 and D2, and two capacitors C1 and C2, and performs the double voltage commutation of the signal voltage outputted from the call sound source B, then generates a DC voltage of (2xVRING;-180V) as a substrate voltage VSUB for a subscriber circuit main body A. Also, a diode D3 as a protection circuit F is connected between the substrate voltage input terminal of the subscriber circuit main body A, and a terminal to which the signal from the call sound source is inputted. When the signal voltage from the call sound source becomes excessive transiently by the diode D3, it is clamped by the substrate voltage VSUB. Therefore, an inter-element separation between transistor cells in the subscriber circuit main body A that is made into the LSI by the PN junction separating system is secured by the substrate voltage, and its operation can be stabilized.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a method for applying a substrate voltage to a subscriber circuit of an integrated circuit including a ring tone control function for a telephone. This invention relates to subscriber circuits that can be effectively provided.

(Prior Art) In digital electronic exchanges, the subscriber circuit is integrated into an integrated circuit (L), including the ring tone control function for telephones.
SI) is being attempted.

For example, as shown in Figure 2, a high voltage analog switch S
ν1. The subscriber circuit main body A is made into an LSI by incorporating sW2, and the subscriber circuit is constructed such that the telephone set P is selectively connected to the exchange main body or the ringing sound source B via the analog switches SWI and SW2.

Note that the ringing sound source B is, for example, ±90Vo.

1 [i If z AC voltage V knee 48V (7
) The analog switches Sνl and Sν2 are constructed so as to generate a DC voltage "DBWING" signal.The analog switches Sνl and Sν2 are, for example, SC switches in which a PNP transistor and an NPN l-transistor are connected in a PNPN manner.
This is realized as an R-type switch or the like.

By the way, when analog switches SWI and SW2 that switch such negative voltage signals are simultaneously integrated to form the subscriber circuit main body A into an LSI, the manufacturing process is such that, for example, the internal transistor cells are made dependent on the voltage. Instead, a dielectric separation method that allows mutual separation is adopted. However, this method requires many manufacturing process steps and has problems such as difficulty in reducing costs.

Therefore, it has been considered to employ a general PN junction separation process to convert the subscriber circuit main body A into an LSI, thereby reducing its cost. However, in the main body of the subscriber circuit, which is made into an LSI through the PN junction separation process, it is necessary to stably secure a substrate voltage lower than the signal voltage of the ring tone source B described above. When the switching system is powered on, it is necessary to apply the substrate voltage before applying the signal voltage from the ringing sound source B.

For this reason, there is a problem in that the structure of the subscriber circuit and the peripheral circuits for operating the subscriber circuit, that is, the subscriber circuit, becomes complicated.

(Problems to be Solved by the Invention) When the main body of the subscriber circuit, including the ring tone control function for the telephone, is made into an LSI using the PN junction separation method, there are problems such as ensuring a stable substrate voltage. In view of this, the present invention provides a simple and practical method that can ensure the stability of the substrate voltage for the LSI subscriber circuit and effectively prevent the input of signals exceeding the substrate voltage. The purpose is to provide subscriber circuits with high configuration.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes a ring tone control function for a telephone,
For example, a DC voltage generation circuit that doubles and rectifies the output of a ringing sound source is used to apply the substrate voltage to the subscriber circuit of an exchange that is integrated as a circuit using the PN junction separation method, and a protection circuit is also used. The present invention is characterized in that the signal voltage supplied from the ringing tone source to the subscriber circuit body does not exceed the substrate voltage using the above-mentioned ring tone source.

(Function) According to the present invention, the substrate voltage is stably generated using the output of the ringing sound source.

Further, by using the substrate voltage, the signal voltage from the ringing sound source is suppressed from exceeding the substrate voltage. Therefore, the operation of the subscriber circuit body integrated as a circuit using the PN junction separation method is stabilized, and the structure thereof is not complicated.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an embodiment circuit, and A is a telephone P
The main body of the subscriber circuit, including the ring tone control function, is implemented as an LSI using, for example, a PN junction separation method. Further, B is, for example, ±90Vo.

1 [111z (7) AC voltage V + knee 48V (7
) This is a ringing sound source that generates a signal multiplied by DC voltage "BB".

However, the voltage doubler rectifier circuit E connected to the ringing sound source B
is composed of two diodes Dl and D2 and two capacitors C1 and C2, and doubles and rectifies the signal voltage output from the ringing sound source B to obtain (2X VR,
N,; -180V) No direct i? l[f is generated as the substrate voltage vsU13 for the subscriber circuit main body A.

Further, between the substrate voltage input terminal of the subscriber circuit main body A and the terminal for inputting the signal from the ringing sound source,
A diode D3 as a protection circuit F is connected.

By this diode D3, when the signal voltage from the ringing sound source B becomes transiently excessive, it is clamped at the substrate voltage vsUB.

In other words, the voltage of the signal manually input from the ringing sound source B to the subscriber circuit main body A is suppressed to below the substrate voltage v8UB. Note that R1°R2 are resistances.

According to the subscriber circuit configured in this way, the voltage of the ringing signal input from the ringing sound source B to the subscriber circuit main body A in the steady state is VIN(-V -V)c,
The minimum value Q is 138V, and the BB RING is always the substrate voltage V (-180V)U.
B or less.

Therefore, element isolation between the transistor cells of the subscriber circuit body A, which is formed into an LSI using the PN junction isolation method, is stably ensured by the substrate voltage, and its operation is stabilized.

Further, when the circuit is powered on, a state occurs transiently in which the above-mentioned substrate voltage V is not sufficiently applied to the subscriber circuit body A due to the operation delay of the voltage doubler rectifier circuit E.

However, at this time, the diode D3 causes the calling sound source B to
Since the voltage VIN of the signal from the subscriber OB is suppressed to the substrate voltage V at that time, a signal with a voltage exceeding the substrate OB trait voltage V is not applied to the subscriber OB circuit main body A. Therefore, no failure will occur in the subscriber circuit main body A, which is formed into an LSI using the PN junction separation method.

In this way, this circuit uses a small number of additional components, that is, two diodes D1. D2 and 2
By using the two capacitors C1 and C2 and the diode D3 as a protection circuit, it is possible to ensure that the substrate voltage V to the subscriber circuit main body A remains stable and to prevent excessive input. Therefore, it is possible to fabricate the subscriber circuit main body A into an LSI at low cost by using a general PN junction separation process.

Note that the present invention is not limited to the embodiments described above, and can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As explained hereafter, according to the present invention, the main body of the subscriber circuit can be made into an LSI at low cost by the PN junction separation process, and the subscriber circuit can be made into an LSI with a small number of additional parts. Great practical effects can be achieved, such as ensuring stability of the substrate voltage V to the main body and preventing excessive input.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a subscriber circuit according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining the functions of the subscriber circuit. A... LSI subscriber circuit body, B... Ringing sound source, E... Voltage doubler rectifier circuit, F... Protection circuit, D
L. D2. D3...Diode, C1, C2...Capacitor, R1, R2...Resistance. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (2)

[Claims] (1) The main body of the subscriber circuit of the exchange, which is an integrated circuit including the control function of the ring tone for the telephone, the ring tone source connected to the main body of the subscriber circuit, and the output of this ring tone source is voltage-doubled and rectified. A subscriber circuit comprising: a DC voltage generation circuit that applies a substrate voltage to the subscriber circuit body; and a protection circuit that suppresses the voltage supplied to the subscriber circuit body below the substrate voltage. (2) The subscriber circuit according to claim 1, wherein the subscriber circuit main body is integrated into a circuit using a PN junction separation method.