JPH05343981A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To obtain a semiconductor integrated circuit in which the influence of a switching characteristic of a logic circuit (delay time) on a temperature change through comparatively simple circuit configuration concerning to the semiconductor integrated circuit of an ECL circuit. CONSTITUTION:This semiconductor integrated circuit is provided with a logic level control circuit C in which when a potential at a control terminal (a) gets higher, a logic amplitude is smaller, and when the potential at the control terminal (a) gets lower, the logic amplitude is larger and with a control element D1 connecting in series with the control terminal (a) of the logic amplitude control circuit C, whose impedance is smaller as temperature gets higher, whose impedance is larger as temperature gets lower. Then the fluctuation in the output logic amplitude of the circuit due to a temperature change is cancelled by the control of the logic amplitude control circuit C due to an impedance change in the control element D1 to eliminate the temperature dependence of the switching characteristic of the circuit.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an ECL (Emitter-Couple
d Logic) circuit semiconductor integrated circuit, and more particularly to a semiconductor integrated circuit that eliminates the influence of the temperature change of the switching characteristics (delay time) of the logic circuit.

A logic circuit that constitutes a semiconductor integrated circuit usually has a characteristic that switching characteristics also fluctuate with temperature fluctuations. This characteristic is often not a problem when using a semiconductor integrated circuit, except for very special cases. However, this characteristic may be a problem depending on the application of the semiconductor integrated circuit.
In such a case, it becomes necessary to cancel fluctuations in switching characteristics (delay time) due to temperature fluctuations.

[0003]

2. Description of the Related Art Conventionally, when a semiconductor integrated circuit is used in electronic equipment, signal logic processing is the main function of the semiconductor integrated circuit, and even if the switching characteristics (delay time) fluctuates to some extent, there is a problem. The device design has been made so that it will not happen.

However, as the applications of semiconductor integrated circuits have expanded, there have been cases where device design is made to utilize the switching characteristics (delay time) itself of the semiconductor integrated circuit. For example, this is a semiconductor integrated circuit that compensates for a certain fixed delay time or controls the delay time. In such a semiconductor integrated circuit, accuracy of the absolute value of the delay time is required.

In an ECL circuit, which is a typical circuit for processing high-speed signals, the output amplitude increases as the temperature rises, and the switching characteristics (delay time) deteriorate. The cause of the large output amplitude is due to the temperature characteristic of the internal bias circuit, and if the internal bias circuit is adjusted, it is possible to make the characteristic such that the switching characteristic (delay time) does not deteriorate with temperature. ..

However, the characteristic of the internal bias circuit is an important parameter for determining the input / output interface level, and in order to adjust this, the input / output circuit and the internal circuit are separated to form the bias circuit. Since it is expected that the circuit configuration will be complicated and the circuit configuration will be complicated, the problem of the switching characteristic with respect to temperature fluctuation is not usually solved by such a method.

[0007]

As described above, in the conventional semiconductor integrated circuit, there is no suitable method for canceling the fluctuation of the switching characteristic (delay time) with respect to the temperature fluctuation. For example, even in the ECL circuit, the internal Although a method of adjusting the characteristics of the bias circuit can be considered, there is a problem that the circuit configuration becomes complicated due to the influence on the input / output interface level.

The present invention solves the above problems,
An object of the present invention is to provide a semiconductor integrated circuit which has a relatively simple circuit configuration and is free from the influence of the temperature change of the switching characteristics (delay time) of the logic circuit.

[0009]

In order to solve the above-mentioned problems, the semiconductor integrated circuit of the first feature of the present invention is, as shown in FIG. 1 or 3, a logic amplitude control for controlling the logic amplitude of the circuit output. A semiconductor integrated circuit of an ECL circuit including a circuit C, which is connected in series to a control terminal a of the logic amplitude control circuit C, the impedance decreases when the temperature rises, and the impedance increases when the temperature falls. It is configured to include the element D1 or R1.

The semiconductor integrated circuit of the second feature of the present invention is
In the semiconductor integrated circuit according to claim 1, in the logic amplitude control circuit C, the logic amplitude decreases when the potential of the control terminal a increases, and the logic amplitude increases when the potential of the control terminal a decreases.

The semiconductor integrated circuit according to the third aspect of the present invention is the semiconductor integrated circuit according to claim 1 or 2, wherein the control element is a diode D1 as shown in FIG.
Is.

Furthermore, the semiconductor integrated circuit according to the fourth aspect of the present invention is the semiconductor integrated circuit according to claim 1 or 2, wherein the control element has a resistor R1 having a negative temperature coefficient as shown in FIG. Is.

[0013]

In the semiconductor integrated circuit of the first, second, third and fourth features of the present invention, as shown in FIG. 1 or 3, the output amplitude varying control terminal CTL is provided and the control terminal a of the control terminal a is changed. The logic amplitude control circuit C, in which the logic amplitude of the output decreases when the potential increases and the logic amplitude of the output increases when the potential of the control terminal a decreases, is configured on the load side of the differential pair Q1 and Q2 to increase the temperature. As a control element in which the impedance decreases when the temperature decreases and the impedance increases when the temperature decreases, the diode D1 (FIG. 1) or the resistor R1 having a negative temperature coefficient (FIG. 3) is connected to the control terminal a of the logic amplitude control circuit C. Are connected in series.

When the temperature rises, the logic amplitude of the output of the semiconductor integrated circuit tends to increase. On the other hand, the impedance of the control element D1 or R1 decreases and the potential of the control terminal a increases, so that the logic amplitude control is performed. The circuit C works to reduce the logical amplitude of the output. Therefore, the fluctuations of the logical amplitude of the output are canceled by the tendency of both of them, the fluctuations of the switching characteristics (delay time) are also eliminated, and the temperature dependence of the switching characteristics (delay time) can be eliminated.

[0015]

Embodiments of the present invention will now be described with reference to the drawings. First Embodiment FIG. 1 shows a circuit diagram of a semiconductor integrated circuit according to a first embodiment of the present invention.

In the figure, the semiconductor integrated circuit of this embodiment has a structure in which a logic amplitude control circuit C and a diode D1 are provided to an ECL circuit having a normal differential pair Q1 and Q2.

The logic amplitude control circuit C includes a transistor Q
8, Q9, and Q10 and resistors R2, R3, R4,
And R5 (R2 <R3, R2 = R4, R3 = R5), the logical amplitude of the output decreases when the potential of the control terminal a increases due to the input voltage to the output amplitude varying control terminal CTL. The lower the potential of a, the larger the logical amplitude of the output.

The diode D1 has a control terminal a of the logic amplitude control circuit C and a control terminal C for varying the output amplitude.
It is connected between TLs and has a characteristic that the impedance decreases as the temperature rises and the impedance increases as the temperature lowers.

First, the output amplitude varying control terminal C
Consider a case where the potential of TL is fixed and the voltage across the diode D1 is constant (or there is no diode D1). In this case, if the temperature rises,
As indicated by the broken line in (1), the logic amplitude of the output of the semiconductor integrated circuit tends to increase. Further, the switching characteristic (delay time) also fluctuates (becomes slower) as shown by the broken line in FIG. 2 (2) due to the increase in the logical amplitude of the output.

Next, when the impedance of the diode D1 changes (the diode D1 exists) due to the temperature change, the impedance of the control element D1 becomes smaller (the voltage at both ends becomes smaller) as the temperature rises. In order to raise the potential of the control terminal a, the logic amplitude control circuit C works to reduce the logic amplitude of the output.

Therefore, the tendency that the logical amplitude of the output becomes large (the former) is canceled by the control of the logical amplitude control circuit C (see the solid line in FIG. 2A), and the fluctuation of the switching characteristic (delay time) also disappears ( 2 (see the solid line in FIG. 2), the temperature dependence of the switching characteristic (delay time) disappears. Second Embodiment FIG. 3 shows a circuit diagram of a semiconductor integrated circuit according to a second embodiment of the present invention.

In the semiconductor integrated circuit of this embodiment, the resistor R1 having a negative temperature coefficient is used as the control element in the first embodiment.
Using transistors Q8 and Q9 and a resistor R
2, R3, R4, and R5 (R2 <R3, R2 = R4,
The logic amplitude control circuit C ′ composed of R3 = R5) is used. The characteristic action is almost the same as that of the first embodiment.

[0023]

As described above, according to the present invention,
When the potential of the control terminal becomes high, the logical amplitude of the output becomes small, and when the potential of the control terminal becomes low, the logical amplitude of the output becomes large. Since a diode or a resistor having a negative temperature coefficient is connected in series to the control terminal a of the logic amplitude control circuit C as a control element whose impedance is small and whose impedance increases when the temperature becomes low, when the temperature rises , The output of the semiconductor integrated circuit tends to have a large logical amplitude, but on the other hand, the impedance of the control element decreases and the potential of the control terminal rises, so the logical amplitude control circuit tends to reduce the logical amplitude of the output. The fluctuations in the output logical amplitude are canceled by these two tendencies, and the fluctuations in the switching characteristics (delay time) also disappear. It is possible to provide a semiconductor integrated circuit capable of eliminating the temperature dependency of the ring characteristics (delay time).

[Brief description of drawings]

FIG. 1 is a circuit diagram of a semiconductor integrated circuit according to a first embodiment of the present invention.

2 is a characteristic curve of the semiconductor integrated circuit of the first embodiment, FIG. 2 (1) shows a temperature characteristic of an output logical amplitude, and FIG.
(2) is the characteristic of the delay time with respect to the change in the logical amplitude of the output.

FIG. 3 is a circuit diagram of a semiconductor integrated circuit according to a second embodiment of the present invention.

[Explanation of symbols]

 C, C '... Logic amplitude control circuit D1 ... Diode (control element) R1 ... (having negative temperature coefficient) Resistance (control element) Q1-Q10 ... Transistors R2-R8 ... Resistors Vcc, Vee ... Power supplies A1, XA1 ... Input terminal X, Y ... Output terminal CTL ... Output amplitude variable control terminal a ... Control terminal

Claims (4)

[Claims] 1. A semiconductor integrated circuit of an ECL circuit, comprising a logic amplitude control circuit (C) for controlling a logic amplitude of a circuit output, which is connected in series to a control terminal (a) of the logic amplitude control circuit (C). The semiconductor integrated circuit has a control element (D1 or R1) whose impedance decreases as the temperature rises and which increases as the temperature lowers. 2. The logic amplitude control circuit (C) is characterized in that the logic amplitude decreases when the potential of the control terminal (a) increases and the logic amplitude increases when the potential of the control terminal (a) decreases. The semiconductor integrated circuit according to claim 1. 3. The semiconductor integrated circuit according to claim 1, wherein the control element is a diode (D1). 4. The semiconductor integrated circuit according to claim 1, wherein the control element is a resistor (R1) having a negative temperature coefficient.