JPS58101556A - Direct current supply and interrupting circuit - Google Patents

Abstract

PURPOSE:To attain a DC current supply circuit to a telephone set, suitable to constitute a semiconductor integrated circuit capable of current interruption easily, by short-circuiting between a gate and a cathode of a gate turnoff PNPN switch, when the interruption of current is desired. CONSTITUTION:A telephone set 3 receives current supply from a DC current supply circuit 11 variable for an in ternal resistance via a DC current polarity inverting circuit 12. The circuit 11 consists of a reference resistor R0, and current transmission circuit Aa-Cb, and at the current supply, a current of about 100mA having internal resistor of 440OMEGA is supplied to the telephone set. When the interruption of current is desired, a negative feedback path of a current transfer circuit is interrupted with transistors (TRs)Q1,Q2, the internal resistance of the circuit 11 is made to almost 44kOMEGA. In the circuit 12 consisting of gate turn-off PNPN switches S1-S4, between the gate and cathode of PNN switches S1-S4 are short-circuited with TRQ3-Q6 when the current interruption is desired, to interrupt current by the aid of high internal resistance of the circuit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a DC current supply circuit to a four-way wire etc. in an IEIt exchange fsK, and is suitable for semiconductor integration.
This relates to the tLL supply cutoff circuit.

Letter coils were used as DC current supply circuits in the case, but in time-sharing exchange, each input
If an attempt was made to adopt a configuration in which a DC current supply circuit is provided in response, there is a problem in that the fi capacity becomes large. For this reason, a proposal has been made to reduce the size of the device by converting it into an electronic device or into a semiconductor integrated circuit. Figure i41 shows its typical configuration. 1 is an electronic DC current supply circuit with characteristics equivalent to a letter coil, 2 is a 4-piece 0PNPN switch S
DC lICl314j composed of tmS wealth*Sa*攬
Gender reversal circuit, 5 is 1 story bond.

Direct current supply in such a configuration 1IiII! In the III Ugu, the PNPN switch 4.54 or 5. , In order to release the electronic device m1llC flow supply circuit 1, should the electronic device be equipped with an accent gate and shut-off,
It is necessary to have a PNPNNpN switch A~S-to turn-off 4#I total. Here, assume DC #L flow" (1
00-If it is necessary to cut off a large current in the root skin, it is difficult to use a semiconductor integrated pNpN switch to turn off the gate.

The present invention was devised in view of the above situation, and an object of the present invention is to provide a DC supply cutoff time circuit which is implemented as a semiconductor integrated circuit and can easily perform 1ilv1 of DC current.

In the present invention, when there is a gate turn-off PNPN switch t-NA formed into a semiconductor integrated circuit, the PNPN switch is short-circuited between its gate and cathode when cut-off is desired.
Rather than using a PN switch to reduce the current in the DC supply path 1IiIIIA to the current level of the root bark that is undergoing gate turn-off, it is possible to cut off the DC supply. do.

The present invention will be explained below using an actual circuit shown in #1kmK as shown in 1!81rIjJ. FIG. 2 shows a striped 10 embodiment of the present invention. In the figure, 11 is a DC 11E flow supply path with variable internal resistance, and 3 is a reference resistance, AM.

AIe I Ja @ 84 @ 'g s ' 4 is direct #LIIIE flow supply 1 path 11 ff1i [anti-t-reference resistance Roo '/, can flow transmission 4 constituting negative feedback 1 path
11111114%Q-Q* is a transistor that cuts off the negative voltage path. 12 is tL current tlL polarity opposite 4Ii
- path, S, ~S4 is a PNPN switch, Q.

~Q is a gate turn-off eyebrow O transistor. 1
s is the wax source with voltage Van (481').

The internal resistance 16 of the current supply circuit 11 is the current transmission tm path'('a s "b) s B (Bg *
84) * ('(Cα, C Todoroki) O″llIc flow rate 4 rates a, l/ respectively.

If it is r, then R0 Rpa・÷4. β; 7°-1t). Transistor Q * * Qmk ON
When the negative feedback circuit constituted by the transmission circuits A, B, and C is interrupted, the resistance resistance 1hl of the Fki section becomes Rg
B, = 2R, (2), that is, the internal resistance is multiplied by α and β.

Usually, Iiii*ox 440Ω is selected, and the source 4 is 14
Since 8F is used, pNp up to a current of 10mA 4 degrees
It will flow through the N switches 51 to S4. It is not easy to turn off this current with a single-path semiconductor integrated pNpN switch.

However, according to the present invention, if the reference resistor is set to 10 kjl and the negative 11 kR path is cut off by the transistor Qt-(b) when the DC supply is cut off, the PNPN switches 51 to S
Since the internal resistance is increased as shown in equation (2) above, the current flowing through 4 can be lowered by l mJ root fi K. Therefore, if the current is i degrees, the semiconductor integrated circuit 1
PNPN switch S.

~S, but it can be easily disconnected by short-circuiting the gate and cathode with transistors Q and ~Q, respectively.

Figure 5 is an equivalent circuit showing a second example of a single-source circuit, and the reference resistance R8 of the DC 11E current supply circuit 11 shown in Figure 2 is
This shows an example of the configuration of a field in which * is followed by the midpoint 'threshold value Ly@. ' In the s5 diagram, Roha constant aha, A, B,
C is a current transmission path 1Ii- path similar to that shown in FIG.

In this -path configuration, constant IiE flow-II (by cutting off Q and turning on 9 transistors, the negative feedback path is cut off,
By setting the internal resistance Rs s,' of the direct dL4 flow supply line 21 to Ri +2R0-...t2f, it becomes a 4i resistance, and the pNpN switches 51 to S
4 is a dirt turn or made busy dIi accent blocking can be done easily.

Although the embodiments described above have all shown examples of configurations of Senryo type circuits, the present invention can also be applied to Fumio type II circuits. Further, the wide current communication circuits A, B, and C in the 5XaS may be the well-known 112-14, or may be constructed using a podium width switch.

Furthermore, the gate turn-or operation of the PNPN switches S and ~S4 not only short-circuits the gate cathode threshold, but also turns the gate to a lower potential. 4! Of course, it is also possible to use a circuit configuration that uses t-channel flow.
It is.

As described above, the present invention provides a PNPN switch by lowering the resistance (1h) of the reference resistor R0 in the IlIc style Itg supply circuits 11 and 21 at all times. When the DC supply is cut off, the global lIt is supplied to the

By increasing the resistance of the resistance sources in the Joki Supply-411 and 21, the flow It flows to the pNpN switches S and ~S4 is reduced to four small flows, and at this time the pNpN switch is gate turned off. , DC'IIEfI1.
The IPIriI4 can be made very easily and is very convenient for making this Hashiji semiconductor integrated circuit.

[Brief explanation of the drawing]

##11 is a circuit diagram of a conventional DC current supply line #1. #I2 and 45 are ig circuit diagrams showing two embodiments of the DC 4Cfi supply circuit including one embodiment of the DC supply cutoff circuit according to the present invention. 11.21...DC single current supply circuit 12...DC current polarity inversion circuit Ro...Reference resistors A, B, C...-current communication circuit Q=-Q*-Qma...transistor Diary~S4... pNpN' switch Qa~Qs... Gate turn-off transistor...
...Constant current source l Figure 3 [i8 1 Continued from page 1 ■ Applicant Nippon Telegraph and Telephone Public Corporation ■ Applicant Oki Electric Industry Co., Ltd. 1-7-12 Toranomon, Minato-ku, Tokyo ■ Applicant NEC Corporation 5-33-1 Shiba, Minato-ku, Tokyo ■Applicant Fujitsu Corporation 1015 Kamiodanaka, Nakahara-ku, Kawasaki City

Claims (1)

[Claims] t A PNPN switch with a gate turn-off function, and a 1m PNPN switch connected in series with the PNPN switch.
It is composed of a DC current supply circuit that switches and supplies two types of current, large and small, to the N switch, and when the DC supply of the PNPN switch is cut off, the DC current supply circuit
A direct current supply cutoff circuit characterized in that the circuit is configured to turn off the gate of the PNPN switch by supplying a small current to the switch. 2. The DC current supply circuit is composed of a resistor, a negative feedback circuit that reduces the resistance value of the resistor, and a transistor that controls the operation of the negative feedback circuit, and the DC current is controlled by turning on and off the transistor. Increase the resistance value in the supply circuit,
2. The direct current supply cutoff path according to claim 1, wherein the current supplied to the PNPN switch is made variable by forming two small types.