JPS5879334A - Logical circuit - Google Patents

Abstract

PURPOSE:To reduce the power consumption, by providing a current mirror circuit inputting an emitter current of an input transistor (TR) for a TR logical circuit. CONSTITUTION:A diode 11 and a TR3' constitute a current mirror circuit inputting the emiter current of an input TR2, one output is obtained from its output terminal 8' and a TR4 is connected to a collector of the input TR via a level shift diode 12 and another output is obtained from its collector. A signal at an input terminal 1 is inverted at the TR2, and an output further inverted at the TRs 3', 4 is generated at outputs 8' and 9. Since a current multiplied by the current amplification factor of the current mirror circuit for the emitter current flows to the TR3' when the TR2 is set on, the TR3' can sufficiently by driven.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to transistor logic circuits, and more particularly to transistor logic circuits useful in integrated circuits operated at low power.

FIG. 1 shows an example of a conventional transistor logic circuit, so-called RTL (Resistor TransistLrL).
FIG. 1 is an input terminal s2, 3.4 is a transistor, 5.
6.7 is a resistor, 8 and 9 are output terminals, and 10 is a power supply.

The signal inputted from terminal 1 is inverted by transistor 2, and inputted from its collector to the respective paces of transistors 3.4 via resistor 6.7. Transistors 3 and 4 are further inverted and outputs are output from terminals 8 and 9, respectively. Resistor 5#i load and J)%10 is the power supply.

Considering the case where the above circuit is formed in an integrated circuit, the practical upper limit for the value of the resistor 5 is about 50Ω from the viewpoint of the area occupied by the circuit board. From the point of view of power consumption, it is preferable for the resistor 5 to be large, so consider setting it to 50Ω. The power consumption of one stage is almost the same as the power consumption of the resistor 5, and if a large number of circuits as shown in Fig. 1 are used, the power consumption will increase, for example, 10
If 0 is used, the power will be 288 mW.

This value is close to the maximum allowable dissipation determined by the integrated circuit package, and means that many other circuits cannot be integrated.

An object of the present invention is to provide a logic circuit with a simple circuit configuration and extremely low power consumption.

According to the present invention, there is obtained a logic circuit characterized by comprising at least an input transistor and a current mirror circuit whose input is the emitter current of the input transistor, and characterized by the input transistor.

Next, the present invention will be described in detail according to embodiments using drawings.

Fig. 2 is a circuit connection diagram showing an embodiment of the present invention, where 1 is an input terminal, 2.3', 4 are transistors, 5' is a constant current source, 8'-9 is an output terminal, and 10 is a power supply. be. The diode 11 and the transistor 3' constitute a current mirror circuit t- which receives the emitter current of the input transistor 2 as an input. Diode 12 is a level shift diode.

In Fig. 1, if the resistor 5 is replaced with a constant current circuit with a small current, it is possible to reduce power consumption, but the voltage drop that occurs across the resistors 6 and 7 is also reduced, and the current hogging of the transistor 3.4 is reduced. This phenomenon occurs, and the collector currents of transistors 3 and 4 no longer flow in a balanced manner. For this reason, it is necessary to make the resistor 6.71 large to provide a predetermined voltage drop, which results in an increase in the area occupied by the resistors 6 and 7, making it impractical.In the present invention, in order to avoid this problem, the current error circuit output terminal 8
′ to obtain one output.

That is, since only the transistor 4 is connected to the collector of the transistor 2 via the level shift diode 12t, not only does current hogging not occur, but also when the transistor 1 is conductive, the current hogging occurs. The current obtained by amplifying and scaling the current of the current mirror is transmitted to the transistor 3'l! Therefore, the transistor 3' can be sufficiently driven.

It is assumed that the output terminals 8' and 9Fx are pulled up to a high potential by, for example, a constant current source (not shown). In this case, the emitter areas of the transistors 3' and 417 are set so that the collector current when the transistors 3' and 417 are conductive has a driving ability that can fully absorb the current of the constant current source. (usually about 1:l to 1:3) The input voltage applied to the input terminal is the transistor 20 base ei, the forward voltage Vl of the dusk.
Forward voltage VF (=VB B
) (When D is larger than (Vn m +VF),
Transistors 2 and 3' are conductive, and terminal 8' has a collector voltage VCI (sa) of transistor 3'.
A low potential output equal to t) is obtained, a 1H" level output approximately equal to the high potential is obtained at terminal 9, and the input is
+VF) When the level is less than 1.1", terminal 8
' high potential ("H" level), low potential ('"L level) at terminal 9.
” level) output is obtained.

Providing multiple constant flow sources is! Multi-collector PNP
) Since it can be realized using a transistor, the area occupied by the element can be significantly reduced compared to the conventional one with the same power consumption, and the value of the constant current source can theoretically be made very small. A power consumption logic circuit is realized. In practice, the value of each constant current source can be set to 1oJIAK, and in that case, the power consumption of one stage is approximately 12 (V) x 10 -' (A)
)] is reduced to 1/8 of the conventional one, and the occupied area can be reduced to the same level or less. The reason for multiplying by three here is that the circuit shown in FIG. 2 is considered to correspond to one stage of logic circuit. However, as shown later, in special cases there is no need to multiply by %3.

FIG. 3 is a circuit connection diagram showing an example of a conventional RTL type R-871 block flop. 31 is a FiR input, 32 is an S input, 33 is a Q output, 34 to 38 are transistors, 39 to 43 are resistors, and 44 is a power supply. For the sake of explanation, first consider when the terminal 31 is at @H" level and the terminal 32 is at @L" level. When the transistor 34 is ON (conducting), its collector potential becomes II L11 -tzb.
Since the transistor 36 is turned off (cut off) and the transistor 37 is also turned off, the collector potentials of the transistors 36 and 37 become 'HIl', and the transistors 35 and 38 are turned on. Next, even if the terminal 30-L" is set, the transistor 35 remains ONI as described above, so the other state NI4
does not change. Next, when the terminal 32t is set to "H", the transistor 37 is turned on, its collector potential is @L", the transistors 35 and 38 are turned off, and the Mayu transistor 34 is also turned off, so the transistors 34, 35 are turned off. Even if the transistor 36 is turned ON and the terminal 32t@L'' is set to 0, the transistor 36 is turned ON as described above, and the other states do not change. - The operation of the S flip-flop was explained.

Similar to the circuit shown in FIG. 1, it is difficult to reduce the power consumption of this circuit.

Figure 4 shows a power-saving R-8 which is another embodiment of the present invention.
It is a circuit connection diagram of flip 70 tube.

Components that are the same as in FIG. 3 are given the same numbers.

In place of the load resistors 39 and 42 in FIG. 3, the present invention uses a constant current source formed by a transistor 47.

In addition, in FIG. 3, since transistors 35 and 38 are connected to the collectors of transistors 36 and 370, resistors 41 and 43 are required to prevent current hogging, but in the present invention, the base of transistor 38 is By changing the connection point, the above-mentioned resistor can be made unnecessary.Since the current flowing through the transistor 38 needs to have a reciprocal relationship with the collector current and the emitter current of the transistors 36 and 37, the transistors 34 and 35 with the inverted output It is made using a current mirror circuit consisting of a diode 45 and a transistor 38. Note that the diode 46 is for level shifting.

When the terminal 31 is at @H'' level and the terminal 32 is at @L level, the transistor 34 is turned on, its collector potential is “L”, and the transistor 36 is turned off.
In addition, since transistor 37 is also OFF, transistor 3
When the collector potential of 6.37 becomes 1H'', the transistor 35 turns on.
Even if the 0th order terminal 31, which is turned on by turning on, is set to @L, there is no change in other conditions because the transistor 35 is turned on. Next, connect terminal 32 to 'H.
'', transistor 37 is turned on, its collector potential becomes ''L'', transistor 35 is turned off, and transistor 34 is also turned off, so transistor 38 and transistor 36 are turned on at the same time. Next, even if we set the terminal 321″@L′″, the transistor 36
Since is ON, other states do not change.

Since this R-8713 block prop requires no resistance other than the power supply circuit 48, the power consumption of the R-8 flip-flop stage can essentially be made as small as desired depending on the setting of the collector current of the transistor 47. 9. For example, by setting this current to t-10 μA, the current can be reduced to 1/2 of the conventional value.
It is possible to make it 0 or less. Inside the power supply circuit 48, approximately α is connected to the diode 53 from the power supply 44 through the resistor 52t'.
A voltage of 7V is generated, a constant current is generated by a circuit consisting of a transistor 50 and a resistor 51, and this is connected to a diode 4.
A desired current source is created by a tilent mirror circuit consisting of a transistor 9 and a transistor 47. Here, for example, resistor 52t2
By setting Ω to 2.6 and Ω to resistor 511-4.2, each collector current of transistor 47 can be set to t-10-m. These resistance values are suitable for integrated circuits. It is possible to supply power from the power supply circuit 4B not only to the transistor 47 but also to other logic circuits.

As described above, according to the present invention, essentially any number of power-saving table transistor logic circuits can be constructed, and the present invention is extremely useful industrially.

[Brief explanation of drawings]

FIG. 1 shows an example of a conventional RTL circuit, FIG. 2 shows an embodiment of the present invention, FIG. 3 shows an example of a conventional R8 flip-flop, and FIG. 4 shows an example of an R8 flip-flop implementing the present invention. It is a circuit connection diagram. 1.31.32...Input terminal, 2,3.3'
. 4.34, 35, 36, 37, 38, 47.50...
...Transistor, 5,6,7,39,40,41゜42.43,51.52...Resistance'% 5'
... Constant current source, 8.8', 9,33.33'
...Output terminal, 10.44...Power supply%
11, 12, 45, 46° 49.53... Diode, 48... Power supply circuit.

Claims (1)

[Claims] Features: an input transistor; a current mirror circuit that receives a transmitter current of the input transistor; and means for obtaining a logic output from at least one of the collector of the input transistor and the output of the current filter circuit. A logic circuit that