JPS59151533A - Device for discriminating ternary input - Google Patents

Abstract

PURPOSE:To attain multi-channel by dividing a discriminator into a discriminating block discriminating the level and a reference block forming a reference voltage to use the reference block in common. CONSTITUTION:The discriminator consists of the reference block 500 forming the reference voltage and the discriminating block 600 discriminating the level of an input signal. When the signal level at an input terminal 100 is lower than the level at a point (a), a transistor (TR) 36 is turned on. When the signal level at the terminal 100 is higher than the level at a point (b), a TR40 is turned off. When input terminals for several channels' share are provided, the block 500 is used in common and the block 600 only is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a three-value input discriminating device for discriminating the level of a digital signal having three types of levels and converting it into a binary signal.

Configuration of conventional example and its problems Conventionally, this type of discrimination device has two types as shown in Fig. 1.
Combinations of sets of comparators have been used. In FIG. 1, 100 is an input terminal to which a ternary signal is supplied, 200 and 300 are binary output terminals, and 400 is a positive power supply terminal.

Further, transistors 1.2, 3, 4, 5, 6°7 and resistors 8, 9.10 constitute a first voltage comparator, and transistors 11.12, 13. i4°15.16.17 and resistors j8, 19.20 constitute a second voltage comparator.

Here, in order to simplify the following explanation, the three-value digital signal supplied to the input terminal 100 will be 5V, 2V,
．． It is assumed that there are three types of levels: 5V and OV, and they are -tjL La'&, Tsuretsure H level, M level, and L level.

The voltage supplied to the positive power supply terminal 400 is 5V.
This supply voltage is divided by resistors 21 and 22°23, and a voltage of 1.5V appears at 8 points of the first supply voltage division point, and a voltage of 3V appears at point b of the second supply voltage division point. Assume that a voltage of .5V appears.

Now, when L level is supplied to the input terminal 100, among the differential transistors forming the comparator,
The transistor on the reference voltage side is turned on, and both output transistors 7 and 17 are turned on (transistors 7 and 17 are oven collector outputs, but it is assumed that some load is connected to the outside). )
When the level of the input terminal 100 reaches the M level, the transistor 1 is turned on and the transistor 7 is turned off.

Note that at this time, the transistor 17 maintains an on state.

When the H level is supplied to the input terminal 100, the transistor 11 is turned on and the transistor 17 is also turned off, so that the output level with respect to the long sword level becomes as shown in Table 1.

Margin below Table 1 By the way, in a system that generally uses ternary-to-binary conversion (usually configured as an LSI to supply a ternary signal to the long pin of an IC), such a discrimination circuit is required. However, if the circuit configuration shown in FIG. 1 is configured for several channels, the circuit becomes extremely large-scale and the current consumption increases.

Even if the circuit shown in Fig. 1 is made into multi-channel, the only elements that can be shared are the dividing resistors 21 to 23, the bias current generation resistors 24 and 25, and the transistor 26, and if these are shared, the wiring will be complicated. There were problems such as:

Regarding current consumption, current always flows through the differential stages of the two sets of voltage comparators, and if the bias current of each differential stage is set to 6oμA (leakage current is (Due to problems, it cannot be reduced unnecessarily.), 100 μA per channel flows regardless of the input level, and there is a lot of waste.

OBJECTS OF THE INVENTION It is an object of the present invention to realize a three-value input discrimination device that has a small number of elements per channel and consumes less current than the prior art.

Structure of the Invention The three-value input discrimination device of the present invention includes a first transistor whose base is connected to an input terminal, and a first reference voltage supply that supplies a first reference rK pressure to the emitter of the first transistor. means, a second transistor having a base connected to the input terminal and having a conductivity type opposite to that of the first transistor, and a second reference voltage supply supplying a second reference voltage to the emitter of the second transistor. a first output transistor that performs an on/off operation based on the on/off operation of the first transistor; and a second output transistor that performs an on/off operation based on the on/off operation of the second transistor. The device is characterized by being equipped with an output transistor, thereby reducing the number of constituent elements and current consumption.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a circuit diagram of a three-value input discrimination device according to an embodiment of the present invention, and the same parts as in FIG. 1 are given the same reference numerals.

In Figure 2, there are resistors 21, 22, 23 for dividing the ginden voltage between the plus side feed line C and the minus side feed line d.
are connected in series, a PNP type transistor 270 base is connected to the first dividing point a, and the transistor 2
The collector of 7 is connected to the negative power supply line d, the emitter of the transistor 29 is connected to the base of an NPN transistor 29 via the diode 28, and the collector of the transistor 29 is connected to the positive power supply line C, and the base and A base bias supply resistor 30 is connected between the plus side feed lines C.

The second dividing point is an NPN transistor 31.
The base of the transistor 31 is connected to the positive power supply line C, the emitter of the transistor 31 is connected to the base of a PNP transistor 33 via a diode 32, and the collector of the transistor 33 is connected to the negative power supply line C. d, and a base bias supply resistor 34 is connected between the base and the negative feed line d.

On the other hand, P N P is connected to the input terminal 100 via a resistor 35.
' type (7) The base of the transistor 36 is connected, and the emitter of the transistor 36 is connected to the transistor 29.
The collector of the transistor 3B is connected to the base of the output transistor 38 via a resistor 37, the emitter of the transistor 3B is connected to the negative power supply line d, and the collector is connected to the first output terminal 200. , a resistor 39 is connected between the base and emitter.

Furthermore, the base of an N P N transistor 40 is connected to the input terminal 1-00 via the resistor 35,
The emitter of the transistor 40 is the same as the transistor 3.
The emitter of the transistor 420 is connected to the emitter of the transistor 420, and its collector is connected to the base of the transistor 420 via the resistor 41. The emitter of the transistor 42 is connected to the positive power supply line C, the collector is connected to the base of the output transistor 44 via a resistor 43, a resistor 46 is connected between the base and the emitter, and the emitter of the transistor 44 is connected to the base of the output transistor 44. is connected to the negative feed line d, its collector is connected to the second output terminal 300, and a resistor 46 is connected between its base and emitter.

Now, to explain the operation of the circuit shown in FIG. 2, first, when the level of the signal supplied to the input terminal 100 becomes lower than the level at point a, the transistor 36 is turned on; When the level becomes higher than the level at point a, the transistor 36 is turned off. On the other hand, when the level of the signal supplied to the input terminal 100 becomes higher than the level at point b, the transistor 40 is turned off, and conversely, when it becomes lower than the level at point b, the transistor 40 is turned off. .

Since the transistors 38 and 42 perform on/off operations based on the on/off operations of the transistors 36 and 40, the output level with respect to the input level is as shown in Table 2.

Table 2 By the way, the discrimination device shown in Fig. 2 can be divided into a reference block 500 that generates a reference voltage and a discrimination block 600 that discriminates the level of an input signal. - When providing a channel, the reference block 500 is shared as shown in FIG. 3, and only the determination block 600 needs to be added, so the circuit configuration becomes extremely simple compared to the conventional one.

Furthermore, as is clear from the previous explanation, when the input signal is at the M level, no current flows through either the transistor 36 or the transistor 40, and when the input signal is at the L level or H level, only one of the transistors flows. Since the circuit is only turned on, the current consumption in the determination block 600 is significantly reduced compared to the conventional case.

It should be noted that the three-value input discriminating device of the present invention is not necessarily limited to the embodiments shown in FIGS. 2 and 3, and various developments and changes can be made as necessary. For example, as long as the reference block 500 has a function of supplying two types of reference voltages to the discrimination block 600, there is no need to be particular about the embodiment, and in the discrimination block 600, the digital circuit serving as the load is MO3. If it is a circuit or the like, the transistor 44 and the resistor 46 are unnecessary. (In the embodiment shown in FIG. 2, an IL circuit is assumed as the load digital circuit, so an open collector type NPN transistor is used.) Effects of the Invention As is clear from the above explanation, the present invention has advantages. The three-value input discrimination device includes a first transistor (corresponding to 36 in the same embodiment) whose base is connected to an input terminal (corresponding to 100 in the above embodiment), and a first reference voltage applied to the emitter of the first transistor. A first reference voltage supplying means, a base of which is connected to the input terminal, and of a conductivity type opposite to that of the first transistor (if the first transistor is a P'NP type transistor, an N P N type transistor is connected to the first reference voltage supply means); a second transistor of the opposite conductivity type (corresponding to 4°); a second reference voltage supply means for supplying a second reference voltage to the emitter of the second transistor; a first output l transistor 38 that performs on/off operations based on the on/off operations of the first transistor;
A second output transistor (44 or 4
2), it can be operated with less current consumption than before, and the circuit configuration itself can be simplified.

Furthermore, in cases where two or more sets of similar discrimination circuits are required, the reference voltage supply means can be shared, and the effect of reducing current consumption and the number of elements compared to conventional methods is significant. .

Still, as shown in the embodiment, the base is connected to the first supply voltage division point, and the third transistor (corresponding to No. 27) is of the same conductivity type as the first transistor (corresponding to No. 36).
and a fourth transistor (corresponding to No. 29) whose base is connected to the emitter side of the third transistor, and whose emitter is connected to the emitter of the first transistor.
and a first reference voltage is supplied by a first power supply means (in the above embodiment, a resistor 29 is used, but a constant current source may also be used) that supplies a base current to the fourth transistor. a fifth transistor (corresponding to No. 31) having a conductivity type opposite to that of the first transistor, the base of which is connected to the second power supply voltage division point; and a base connected to the emitter side of the fifth transistor. a sixth transistor (corresponding to 33) whose emitter is connected to the emitter of the second transistor (corresponding to 40), and a second transistor that supplies current to the base of the sixth transistor. Since the power supply means (corresponding to the resistor 34) constitutes the second reference voltage supply means, the NPN type transistor and the PNP type transistor are effectively used to efficiently supply the first and second reference voltages. It has the advantage of being able to supply information to the discrimination block.

[Brief explanation of the drawing]

FIG. 1 is a circuit connection diagram showing a conventional example, and FIGS. 2 and 3 are circuit connection diagrams showing each embodiment of the present invention. 100...Input terminal, 200...Output terminal, 300...Output terminal, 500...-...
Reference block, 600...Discrimination block. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 41ρ Figure 2

Claims (2)

[Claims] (1) a first transistor having a base connected to an input terminal; a first reference voltage supply means for supplying a first reference voltage to an emitter of the first transistor; and a base connected to the input terminal; , a second transistor having a conductivity type opposite to that of the first transistor, a second reference voltage supply means for supplying a second reference voltage to the emitter of the second transistor, and an on/off state of the first transistor. A three-value input comprising a first output transistor that performs an on/off operation based on an off operation, and a second output transistor that performs an on/off operation based on an on/off operation of the second transistor. Discrimination device. (2) the base is connected to the first supply voltage dividing point;
a third transistor of the same conductivity type as the first transistor; a fourth transistor whose base is connected to the emitter side of the third transistor and whose emitter is connected to the emitter of the first transistor; The first power supply means for supplying the base current to the fourth transistor constitutes the first reference voltage supply means, the base is connected to the second power supply voltage division point, and the fourth transistor is of the opposite conductivity type. a fifth transistor, a sixth transistor whose base is connected to the emitter and rear side of the fifth transistor, and whose emitter is connected to the emitter of the second transistor; and a sixth transistor whose base is connected to the emitter of the second transistor; Claim 1 (1) is characterized in that the second reference voltage supply means is constituted by the second power supply means that supplies the reference voltage.
3-value input discrimination device described in ).