JPH0263216A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To reduce the cost of a semiconductor integrated circuit and to make the size small by obtaining a control signal for a Miller killer circuit from an anode of a diode so as to eliminate the need for a resistor and a transistor(TR). CONSTITUTION:A Miller killer circuit is controlled by an anode potential of a diode 14. That is, when a TR 10 is turned off, that is, when a TR 8 is turned off, a current from a resistor 23 turns off a TR 11 through diodes 29, 30 to extract a base electric charge of a TR 10. When the TR 10 is turned on, that is, the TR 8 is turned on, the current from the resistor 23 flows to the diode 14, the base electric charge of the TR 11 is extracted through a resistor 25 and the TR 11 is turned off not to disturb the turning-on of the TR 10. Thus, number of components is reduced and an inexpensive Miller killer circuit is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an output circuit of a bipolar digital semiconductor integrated circuit device, and particularly to a Miller killer circuit.

[Conventional technology]

Figure 2 shows the 1987 edition of the Mitsubishi Semiconductor Data Book AS.
It is a circuit diagram of the output part of the Pipolar Digital E-C described in 'rTL) edition. In the above, (1) is the signal line from the input circuit, (2) is the signal line from the output control circuit, (
3) is the output terminal, (4) is the power supply terminal, (5) is the GND terminal, (6) to (2) are NPN with Schottky clamp)
transistors, (to) are NPN) transistors, 04 to 0 are Schottky barrier diodes (hereinafter, χ Schottky barrier diodes and PN junction diodes will not be distinguished unless particularly necessary), and 翰 to Z are resistors.

Here, transistors (6), (b), resistors (1),
@]) and (c) constitute a mirror killer circuit.

Next, we will explain the Miller effect and the operation of the Miller killer circuit that prevents it.0 When the collector potential of a transistor rises, the base
A current flows from the collector to the base through the collector-collector capacitance, and the current flowing into the base becomes the base current and turns on the transistor, causing a collector current hyz times that amount to flow. In this way, the Miller effect causes a much larger collector current to flow than would be expected from the base-collector capacitance alone.

In the circuit shown in Figure 2, the capacitance between the base and collector of transistor a1 is large, and the amplitude of the potential at the output terminal (3) is large, so when the potential at the output terminal (3) rises, there is a mirror effect of 1 on the transistor. becomes a big problem.

The Miller killer circuit included in the circuit shown in Figure 2 has the function of draining the current that has flowed into the base of transistor (1) to the GND terminal (5) through the transistor (α) in order to prevent the above-mentioned Miller effect. be.

However, if one of the transistors is always on, it will prevent transistor a1 from turning on, so transistor a1
When the transistor (6) should be turned on, that is, when the input t1) is at a high potential, the transistor (6) is turned on, lowering the base potential of the transistor (b), and turning off the transistor (b). Also, the resistor υ is a resistor for limiting the base current of the transistor (b). The resistor @ is used to drain the base charge when the transistor (6) is turned off, and together with the resistor (a), it divides the voltage of the input (1) so that the input voltage is at an appropriate level (the bipolar IC cited above).
In the case of '1.0V) when it becomes K, the transistor (6)
It also has the function of turning on the

[Problem to be solved by the invention]

Since the conventional Miller killer circuit was constructed as described above, it required two transistors and three resistors.

This invention was made in order to reduce the number of elements required for a Miller killer circuit, and it has a Miller killer circuit that has the same effect as the conventional circuit but has a reduced number of elements and can be manufactured at a low cost. The purpose is to obtain semiconductor integrated circuits.

[Means to solve the problem]

The Miller killer circuit in the semiconductor integrated circuit according to the present invention is one in which the transistor (6) and resistors (4) and (c) for controlling on/off of the Miller killer transistor 0η are eliminated.

[Effect]

The Miller killer circuit in this invention is controlled from the anode of diode α through level shift means.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 翰 and (to) are diodes used as level shifting means. Note that the other symbols are the same as those of the prior art, so the explanation will be omitted.

In the circuit of the present invention, the Miller killer circuit is controlled by the anode potential of the diode σ♦, so first, the operation of the diode α and the transistor (8) will be explained. Transistor (8) is connected to output terminal (3) through diode α when transistor αQ is turned on.
flows into the base of transistor α, which speeds up the on-state of transistor I:lG, increases the collector current of transistor a1 (considered to be ha11 times the base current), and causes the output terminal (3) potential to fall. Speed up shi. When the potential of the output terminal (3) decreases, the diode αQ
is turned off when sufficient forward voltage cannot be obtained. When the diode Qfl is turned off, the resistor 11 supplies the necessary base current to the transistor α. Diode α◆
When the output terminal (3) is in a high impedance state, the current flows through the diode α and the resistor (to) to the power supply terminal (Vc
c) It prevents the flow into (4).

As described above, the transistor (8) also turns on when the transistor U should turn on, so the Miller killer circuit only needs to turn on when the transistor (8) turns off. Therefore, in the Miller killer circuit of the present invention, the base potential of the Miller killer transistor (b) is controlled by the collector potential of the transistor (8). However, since the collector potential of the transistor (8) is connected to the potential of the output terminal (3) through the diode αQ, when the output terminal (3) is in a high impedance state, the collector potential of the transistor (8) is directly connected to the Miller killer circuit from the O collector. When current is applied, leakage current flows from the output terminal (3), which is not desirable. Therefore, in the present invention, the mirror killer circuit is controlled via a diode (b) to prevent leakage current from occurring. In addition, while the mirror killer transistor (b) turns off at a pace of 0.7 VQ degree, the anode first position of diode α◆ can only drop to about 1.5V, so the transistor at the anode potential of diode α◆ Level shift means is required to control on/off of (b). In this embodiment, two diodes connected in series are used as the level shifting means. Since the Miller killer circuit according to the present invention is configured in this way, when the transistor a1 should be turned off, that is, the transistor (8) is turned off. When the current from the wire (to the resistor) flows through the diode, the transistor (b)
Turns off and removes the base charge of the transistor. Also, when the transistor (8) should be turned on, the current from the resistor (to) flows to the diode Q4, and the base charge of the transistor (b) is extracted through the resistor (a). OFF, does not prevent the transistor aQ from turning on.The above explanation is the same as in the conventional example, but the elements required for the Miller killer circuit in this invention are the transistor (b), the diode wire, and the diode. ,
There are four points of resistance (c), and the transistor (c) in the conventional case.
6) Compared to (b), resistance (e), an, (c),
One point has been reduced. In addition, in bipolar integrated circuits, the area occupied by one element generally has the largest resistance,
This is followed by transistors and diodes, so the area required for the Miller killer circuit is actually reduced to about 1/2 by this invention.In addition, in the above embodiment, four diodes are used as the level shift means, and four diodes are used as the level shift means. This diode is P
It may be either an N-junction diode or a Schottky barrier diode. Further, a resistor can be used as a level shift means, or a resistor and a diode can be connected in series. Since the semiconductor integrated circuits are obtained from nanonodes of 100 to 100, resistors and transistors can be omitted, and semiconductor integrated circuits can be made smaller and cheaper.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an output portion of a semiconductor integrated circuit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an output portion of a conventional semiconductor integrated circuit. In the figure, the a value is +8), (b) is a transistor, (b) is a diode, slope is a resistor, and (2) and (to) are diodes used as level shift means. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A first transistor having a collector connected to an output terminal and an emitter connected to a low potential power source; a second transistor having an emitter connected to the base of the first transistor; and a cathode connected to the second transistor. a resistor connected between the anode of the diode and a high potential power source; and a third transistor whose collector is connected to the base of the first transistor and whose emitter is connected to the low potential power source. A semiconductor integrated circuit comprising: a transistor, wherein the anode of the diode and the base of the third transistor are connected via a resistor, a diode, or a combination circuit of a resistor and a diode.