JPH03198420A - Logic integrated circuit - Google Patents

Abstract

PURPOSE:To incorporate a current switching type logic circuit with two kinds of logic circuit different in use power supply voltage and input/output logical level by providing the current switching type logic circuit with a supply voltage comparing circuit and two reference voltage generating circuits and output circuits. CONSTITUTION:A comparing circuit 1 divides a power supply voltage and compares the result with the potential of a reference voltage set signal input terminal 9. An input circuit 4 amplifies the potential of an input signal terminal 11 with the potential at the common connection point between output terminals of first and second reference voltage generating circuits 2 and 3 as the threshold voltage, and supplies the amplified potential to an internal circuit 5. First and second output circuits 7 and 8 connected in parallel to the output terminal of the internal circuit 5 consist of current switching type logic circuits and transistors which take out the output signals by emitter followers. An output switching circuit 6 receives the output signal of the comparing circuit 1 to select and drive one of first and second output circuits 7 and 8. Thus, the current switching type logic circuit is free from malfunction even in the case of the use of two different kinds of logical level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a logic integrated circuit, and particularly to a semiconductor device equipped with a current switching type logic circuit.

[Conventional technology]

Conventional current switching type logic circuits have two types of input/output logic levels, but in one current switching type logic circuit, the input/output logic level is fixed.

[Problem to be solved by the invention]

The conventional current switching type logic circuit described above has only one type of logic level, so when two types of logic levels are used together, there will be a slight level difference, etc.
There is a drawback that malfunctions occur if the operating margin is significantly reduced.

[Means to solve the problem]

The logic integrated circuit of the present invention includes a comparison circuit that compares a reference voltage setting signal and a power supply voltage, and a first reference voltage generation circuit and a second reference voltage generation circuit that are selectively driven by an output signal of the comparison circuit. , a logic circuit whose threshold voltage is a potential at a common connection point of the output ends of the first reference voltage generation circuit and the second reference voltage generation circuit, and a first output circuit connected in parallel to the output ends of the logic circuit. and a second output circuit, and an output switching circuit that selects either the first output circuit or the second output circuit and puts it into a driving state upon receiving the output signal of the comparison circuit.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of the present invention, and FIG. 2 is a circuit diagram showing an embodiment of the present invention.

The comparison circuit 1 divides the power supply voltage VEE by the resistance ratio t, aZ and compares it with the potential of the reference voltage setting signal input terminal 9.

The first reference voltage generation circuit 2 is a circuit that generates a certain reference voltage VRI, and the second reference voltage generation circuit 3 is a circuit that generates another reference voltage V2 (assumed to be temperature compensated). . The input circuit 4 is an ECL type logic circuit, and changes the potential of the input signal terminal 11 to the first reference voltage generation time w! 52 and the common connection point of the output ends of the second reference voltage generation circuit 3 is amplified as a threshold voltage and supplied to the internal circuit 5 (ECL type logic circuit). A first output circuit 7 connected in parallel to the output end of the internal circuit 5. Each of the second output circuits 8 is composed of a current switching type circuit and a transistor from which an output signal is taken out by an emitter follower. Note that the second output circuit 8 includes diodes Dl and D2 and a resistor R connected in antiparallel.
It has a temperature compensation circuit consisting of IO. Output switching direction w
I6 is a circuit that receives the output signal of the comparator circuit 1, selects either the first output circuit 7 or the second output circuit 8, and puts it into a driving state.

Next, the operation will be explained.

When VEE=-5.2V, if a potential higher than the pace potential of the transistor Ql is applied to the reference voltage setting signal input terminal 9, the transistor Ql is turned off, and the transistor Ql is turned off.
2 is turned on. The pace potential of transistor Q3 becomes low and transistor Q3 is turned off. Transistor Q4
The pace potential becomes the ground potential, turning on the transistor Q4, and the second reference voltage generation circuit 3 is driven to generate the reference voltage ■
Input circuit 2 to circuit 4. Internal circuit 5. First output circuit 7. Second
Supplies the output circuit. Also, the pace potential of transistor Q7 is lower than the ground potential by the voltage drop of resistor R4, but if the reference voltage VR3 is set higher than that potential, Ql is turned off and Q8 is turned on, and the pace potential of transistor Q14 is lowered by the voltage drop of resistor R4. decreases and Ql4 turns off. Therefore, the potential of the output terminal 12 is the same as that of the transistor Q15 of the second output circuit 8.
It is given by the evacuator potential of Therefore, the second output circuit is selected.

Next, when VEE" 5V is applied, when a high voltage lower than the pace potential of the transistor Ql is applied to the reference voltage setting signal input terminal 9, the transistor Q3 is turned on, the reference voltage l is selected, and the first output circuit 7 is turned on. selected.

Above, we have explained the case where when VEE=-5.2V, the reference voltage 2 and the second output circuit 8 are selected, and when VEE=-5V, the reference voltage VRt and the first output circuit 7 are selected. , when VEE=-5, OV, the reference voltage vgt
, the first output circuit 7 is selected, VEE = -5, 2V6
D,! :i! ! , reference voltage VR,2, and second output circuit 8 are also possible.

〔Effect of the invention〕

As explained above, the present invention provides a current switching type logic circuit with a power supply voltage comparison circuit and two systems of reference voltage generation circuits and output circuits, so that two types of power supply voltages and logics with different input/output logic levels can be generated. This has the effect of providing a logic integrated circuit that can be incorporated into a circuit.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is a circuit diagram of an embodiment of the present invention. l...Comparison circuit, 2...First reference voltage generation circuit, 3...Second reference voltage generation circuit, 4°
°°゛°°Input circuit・5・・・・・・Internal circuit, 6・・
... Output switching circuit, 7... First output circuit,
8...Second output circuit, 9...Reference voltage setting signal input terminal, 10...Voltage switching signal line,
11...Input signal terminal, 12...Output signal terminal, DI, D2...Diode, ■1~
14... Constant current source, Ql-Ql5...
Transistor, R1-J'L1o0996. , resistance, V
几1～VR3・・・Reference voltage.

Claims (1)

[Claims] a comparison circuit that compares a reference voltage setting signal and a power supply voltage; a first reference voltage generation circuit and a second reference voltage generation circuit that are selectively driven by the output signal of the comparison circuit; and the first reference voltage generation circuit. and a logic circuit whose threshold voltage is the potential at a common connection point of the output ends of the second reference voltage generation circuit, and a first output circuit and a second output circuit connected in parallel to the output ends of the logic circuit.
an output circuit, and a first
1. A logic integrated circuit comprising: an output switching circuit that selects either the output circuit or the second output circuit and puts it into a driving state.