JPH02128517A - Cmos inverter circuit - Google Patents

Abstract

PURPOSE:To obtain a CMOS inverter circuit where a prescribed drive capability is attained and the radiation noise is reduced by combining a first CMOS inverter for rise and fall and a second CMOS inverter for drive capability. CONSTITUTION:A first CMOS inverter INV2 (TP2 and TN2 of small transistor size) for rise and fall and a second CMOS inverter INV1 (TP1 and TN1 of large transistor size) are combined to constitute the circuit. That is, transistors can be divided to transistors for rise and fall and those for drive capability because two kinds of transistor are used. Thus, when an output signal Y rises or falls, TP1 and TN1 are turned off together and rise and fall are controlled by TP2 and TN2 of small transistor size to reduce the radiation noise; and when the output signal Y is in the high or low level, TP1 or TN1 of large transistor size is turned on to secure a prescribed drive capability.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a CMOS inverter circuit that outputs an inverted signal of an input signal as an output signal, and in particular,
This invention relates to a CMOS inverter circuit that reduces radiation noise.

<Prior Art> Currently, LSIs are becoming more highly integrated and faster due to ultra-fine processing technology, and this has led to problems due to radiation noise, which cannot be ignored.

In the conventional CMOS inverter circuit, as shown in FIG. 2, it is composed of one type of P-channel, N-channel)vMO3) transistors TP and TN. In the same figure, - is a circuit diagram, and in the same figure (b) is a timing chart.

<Problem to be solved by the invention> As mentioned above, since the conventional CMOS inverter circuit is composed of one type of P-channel LV, N-channel/L/MOS transistor, the transistor size has to be reduced in order to reduce radiated noise. If the rise and fall times are made smaller and the rise and fall times are delayed, the drive capacity will be reduced, and if the rise and fall times are made faster, the drive capacity will be increased, but the problem of radiation noise will occur and the problem cannot be solved. That is, since the conventional system is configured with one type of P-channel and N-channel MO8+- transistors, problems remain depending on whether emphasis is placed on drive capability or radiation noise countermeasures.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a CMOS inverter circuit that solves these problems.

A CMOS inverter circuit according to the present invention is a CMOS inverter circuit that outputs an inverted signal of an input signal as an output signal.As shown in FIG. The first CMOS inverter INV2 (TP2.TN2
) and a second CMOS inverter INVI (TPI, TNI) for drive capacity.
: ) lunge y, p size large).

<Operation> As shown in FIG. 1, the present invention uses two types of transistors (TP
I, TNI and TP2. Since TN2) is used, it can be divided into one for rising/falling and one for drive capacity, and thus measures can be taken against drive capacity and radiation noise.

<Embodiment> FIG. 1 shows an embodiment of the present invention, and FIG.
) is a circuit diagram, and (b) is a timing chart.

In the circuit diagram of the first cause, P channel/L/MOS transistor TP2. N channel) vMOS transistor TN
2 is for rising and falling, the transistor size is small, and P channel/I/MOS transistor TP
The I and N channel/L/MOS transistors TNI are for drive capability, and the transistor size is set to be large.

TP2. TN2 is turned on and off, the output signal Y changes between rising and falling, and then either TPI or TNI is turned on by the signal An delayed by the delay circuit DELAY2.
Increase drive ability. OR is or gate, AND
is an and gate. Also, depending on the change in input signal A, either TPI or TNI is turned off (Fig. 1(b)
)).

With this operation, both TPI and TNI are turned off during the rising and falling periods of the output signal Y, and TP2. TN2 controls the rising and falling edges to reduce radiation noise. Also, during the period when the output signal Y is H or L, TPI or TNI, which has a large transistor size, is turned on to maintain the specified drive capability. can be secured.

<Effects of the Invention> As described above in detail, according to the present invention, it is possible to provide an extremely useful CMOS inverter circuit that has a predetermined drive ability and also has reduced radiation noise.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and the same figure shows an embodiment of the present invention.
is a circuit diagram, and the same figure is a timing chart. FIG. 2 shows a conventional circuit, where Ia) is a circuit diagram and FIG. 2B is a timing chart. Code Description INVI: CMOS inverter for drive capacity, I
NV2: CMOS inverter for rising and falling. Agent Patent Attorney Takeshi Sugiyama (1 other person) (b) No. ('Q)! Figure Cb) Figure

Claims (1)

[Claims] 1. CM that outputs an inverted signal of an input signal as an output signal
In the OS inverter circuit, a first CMOS inverter for rising and falling;
A CMOS inverter circuit characterized in that it is configured in combination with a second CMOS inverter for drive capability.