JPS5985155A - Data bus line - Google Patents

Abstract

PURPOSE:To obtain a pull-up efficiency also to the data but line of a commercial/station common use feeding system at the application of commercial power supply by connecting the former with the latter via a transfer circuit. CONSTITUTION:The commercial/station common use feeding system data but line BUS1 and the commercial feeding system data bus line BUS2 having a pull- up resistor connected to a commercial system power supply voltage VAC are connected via a transfer circuit G used as a signal separating circuit. An output of a commercial system power failure detecting circuit 3 is applied to an N-MOS gate C of the transfer circuit G and a P-MOS gate inverting C'. At the application of commercial power supply, the C goes to H and the C' goes to L, the circuit G is conducted bidirectionally, the pull-up resistor 2 is operated to both data bus lines BUS1, BUS2 and when the commercial system is failed, the circuit G is made nonconductive and the data bus lines are separated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides two power supplies: one is a station power supply that supplies a circuit that guarantees all basic telephone functions, and the other is a commercial power source that supplies a circuit that realizes additional functions such as data transmission. The present invention relates to a data bus line used as a signal transfer path in a digital circuit section of a commercial/office power supply system and a commercial power supply system in telephone equipment operated by a power supply.

It has a telephone basic function section that provides basic telephone function services such as making and receiving two calls, and a call function section that provides advanced wind conversation services such as speaker reception and non-telephone services such as data transmission and reception. In telephone equipment, it is not possible to operate all the circuits with just the central power supply. For this purpose, a commercial power supply is used, and in order to guarantee basic telephone functions in the event of a power outage, the telephone basic function section is supplied with combined commercial/station power, and the additional function section is supplied with commercial power. It is common to supply electricity. ,,! In addition, it is common for the control system to perform program control using a microprocessor or microcomputer, and the components that make up the telephone's basic function section, including the microprocessor, must be operated only by power supply from the station. 6MO8 LSI, MSI/SSI, etc., which have low power consumption, are widely used.

It is known that a system composed of 6MO8 digital circuit elements has high impedance as a whole and is therefore more susceptible to induction and radiation noise, especially energy noise, than a system composed of TTL or the like.

The energy noise margin NI of digital circuit elements is (1
) As shown in the formula, the input 'electrical threshold VTH
and the signal line from the outside to its input cloth, pressure len/hold Vhn'! The current required to doshibu (vTI)
(/RO) and the speed t of the gate in response to the noise/pulse.
It is represented by p.

NI = VT)l
■! /Ro fist Φ fist ・
・ (1) Ro: Output impedance of gate, and noise/pulse width of 200 to 300 ns
It has been experimentally known that this is determined only by the output impedance and the output impedance.

Therefore, since there is no strong main sound source such as a high-voltage, high-speed circuit in the same system in telephone equipment, the numerator of equation (1) is a constant, υ, as shown in equation (2). The degree will be inversely proportional to the output impedance of the CMOS gate.

NIc1: K/Ro @Ki... (2) K: Vrm'
, ) The output impedance of the CMOS gate is MS I
It is known that in general-purpose ICs such as /SSI, there is Ω, but in CMOS microprocessors, microcomputers, etc., there is Ω. H,/IoH-2,
4 (V) / 200 (μA) = 12 Ω, which is a fairly high impedance. Therefore, since noise is easily picked up, a method is used in which the data bus line is pulled up to lower its impedance.

For example, if a pull-up resistor of IOKΩ or 5Ω is inserted into the data bus line, the combined resistance will be 5.4Ω for each.
Compared to the case without pull-up, the energy-noise margin is approximately twice (1215, 4) and approximately 3.4 times (12, / 3.5), but if the data bus line is made of 8 trees, rJ: 20 mW will be consumed when the pull-up resistor is 10 Ω, and 40 mW when the pull-up resistor is 5 Ω (%1. When the voltage is 5■),.

Even in the installation H1 of telephone premises equipment, microcomputer
The energy noise margin of data bus lines such as
One of the goals is to secure a general-purpose (ΔUO8IC) such as I, /SSI, etc., but to achieve this, a pull-up resistor of Ω or less is required for 5, and a power of 40 mW or more is required for the pull-amp resistor. However, in order to supply pull-up power from the station power supply to guarantee basic telephone functions, the capacity of the station power supply must be increased by 30% or more, which is currently disadvantageous. Therefore, conventionally, the data bus line of the station power supply system is not pulled up, and even if it is pulled up, the resistance value is between 60Ω and 100Ω, which is a value that is not effective in lowering the impedance. Measures were taken in terms of packaging technology, such as shortening the bus line length.In addition, the data bus line of the commercial power supply system is not subject to strict physical control, so a pull amplifier is used. As shown in Fig. 1, the conventional signal separation circuit 1 is configured with a gate circuit in a tri-cloud state, so that the data bus line B of the commercial 7-station combined power supply system is
US1 and the data bus line BUS2 of the commercial power supply system are electrically separated, and this has been effective only in reducing the impedance of the data bus line BUS2 of the commercial power supply system.

Note that even if there is no pull-up on the data bus line of the fn5 power supply system, if a power outage occurs in the commercial power supply, other commercial equipment, which is considered to be the main noise source in the home system, will also be affected by the power outage. Since it no longer acts as a noise source, there is no influence from that noise source, but it has the disadvantage that it is vulnerable to external energy noise when the commercial power supply is turned on.

Therefore, it is an object of the present invention to provide a data bus line that can also produce a pull-amplification effect on the data bus line of the commercial/office combined power supply system when power is supplied to the intermittent power source. be.

In order to achieve such an object, the present invention comprises a signal separation circuit with a transfer gate circuit, and this transfer gate circuit is turned on when the open system power supply is energized, so that the commercial/station power supply system can be separated. The data bus line is connected to the data bus line of the commercial power supply system.゛However, the present invention adds a pull-up resistor to the data bus line of the commercial 7-station combined power supply system via the transfer gate circuit, and when the commercial power supply is energized, the transfer gate circuit is conductive, and when the commercial power supply is turned on, the transfer gate circuit is It is controlled to be open at 5 o'clock in the evening, and when the commercial power supply is turned on, the data bus of the 1st system of 7-station commercial power supply is pulled up.

Hereinafter, the present invention will be described in detail using drawings showing embodiments.

FIG. 2 is a circuit diagram showing one embodiment of the present invention, and the same parts as in FIG. 1 are designated by the same symbols. In the figure, G is a transfer gate circuit used as a signal separation circuit, 2 is a pull-up resistor connected to a commercial power supply voltage VA○, and 3 is a commercial power supply failure detection circuit. The commercial power supply power failure detection circuit 3 has a configuration in which the commercial power supply voltage vAo is divided by resistors, and a gate circuit Ga such as a Schmitt circuit detects whether or not the voltage is a predetermined voltage. Note that other voltage detection circuits may be used as the commercial power supply power failure detection circuit 3. In addition, in FIG. 2, the transfer gate circuit G
The commercial power failure detection circuit 3 operates with the voltage supplied from the commercial seven-station power supply system.

FIG. 3 shows the element configuration of the transfer gate circuit. By externally applying a control signal C1C to the gates of P-MOS, which is P-channel MO8, and N-MOS, which is N-channel MOS,
It can control the on/off of MOS and FET and can be used as an analog switch. That is, N-MOS
When a control signal of C = 1'H'' (high) is input to the gate of P-MOS and c = 1-L-1 (low) to the gate of P-MOS, both N-MOS and P-MOS are turned on, resulting in bidirectional conduction. becomes. In addition, C=ILJ is applied to the gate of N-MOS, and C=[Hl is applied to the gate of P-MOS.
When a control signal of l is given, an N-MOS.

Both P-MOS are turned off, and the input/output line and output/input line are kept open as high impedance.

Therefore, in FIG. 2, when the commercial power supply is energized, the output of the commercial power failure detection circuit 3 is C-1'H-1, C-"L".
Therefore, the transfer gate circuit G becomes conductive,
The data bus lines BUS1 and BUS2 are electrically connected via the on-resistance of the MOS, and a pull-up resistor 2 can be applied to both edges of the data bus lines BUS1 and BUS2. During a commercial power outage, the output of the commercial power outage detection circuit 3 is C=ILl.

C=FH,,l, and transfer gate circuit G
is opened and the data bus lines BUS1 and BUS2 are separated.

FIG. 4 is a circuit diagram showing another embodiment of the present invention.
The same symbols are used for the same parts and corresponding parts as in the figures and FIG. 2. In the figure, 4 is a pull amplifier resistor connected to the commercial power supply voltage VAO via the transfer gate circuit G to the data bus line BUS1.

In Figure 4, commercial system 1! When the power supply is energized, the output of the commercial power supply failure detection circuit 3 is C=I, similar to the case explained in Fig. 2.
Since H, J, C = f-Lj, the transfer gate circuit G is conductive υ, and the pull-up resistor 4 to the commercial power supply is connected to the data bus line BU of the commercial 7-station combined power supply system.
It will be connected to S1. At the time of a power outage in the commercial system, the output of the power outage output circuit 3 becomes C=1LJ, C=“H”, the transfer gate circuit G is opened, and the pull-up resistor 4 is separated from the data bus line BUS1.

In this way, by controlling the transfer gate circuit on/off by turning on/off the AC commercial power supply, when the commercial power supply is energized, the pull-up resistor to the commercial power supply can also be connected to the data bus of the 7-station commercial power supply system. It can be made to work.

As explained above, the data bus line according to the present invention connects the commercial
Since the data bus line that provides power for multiple stations is connected to a pull-up resistor, even when the commercial power supply is turned on, a pull-up acts on the data bus that provides power for 7 commercial stations, preventing energy from outside. It has the effect of becoming more resistant to noise.

[Brief Description of the Drawings] Figure 1 is a circuit diagram showing an example of a conventional data bus line;
Fig. 2 is a circuit diagram showing one embodiment of the present invention, and Fig. 3 is a circuit diagram showing an embodiment of the present invention.
FIG. 4 is a circuit diagram showing an example of the transfer gate shown in the figure, and FIG. 4 is a circuit diagram showing an embodiment of the pond of the present invention. 1...(M number separation circuit, 2,4φ...resistance, 3.
...Commercial system power failure female 5 detection circuit, G...Transfer gate, BUS1, 2...Data bus line. ) Permit applicant: Nippon Telegraph City Corporation

Claims (2)

[Claims] (1) Data in which a data bus line to which both commercial power and station power are supplied and a data bus line to which commercial power is supplied and a pull-up resistor is connected are connected via a signal separation circuit. In the bus line, the signal separation circuit consists of a transfer gate circuit that turns on when a signal with a first polarity is supplied and turns off when a signal with a second polarity is supplied, and is supplied with commercial power. When the transfer gate circuit is
A data bus line equipped with a commercial power failure detection circuit that supplies a signal with a second polarity to the transfer gate circuit when the commercial power supply is no longer supplied. (2) Data in which a data bus line to which both commercial power and station power are supplied and a data bus line to which commercial power is supplied and a pull-up resistor is connected are connected via a signal separation circuit. In the bus line, a transfer gate circuit that turns on when a signal with a first polarity is supplied and turns off when a signal with a second polarity is supplied, and a commercial power source are supplied. C
and a commercial power failure detection circuit which supplies a signal having a first polarity to the transfer gate circuit, and supplies a signal having a second polarity to the transfer gate circuit when commercial power is no longer supplied. , a data bus line to which both a commercial power source and a local power source are supplied is connected to a separately provided pull-up resistor via a transfer gate circuit.