JPS5930339B2 - hysteresis circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hysteresis circuit that can be easily configured using an integrated circuit, and particularly aims to provide a hysteresis circuit that has a simple circuit configuration and operates with high stability.

The hysteresis circuit of the present invention is, for example, inch-rated.
Injection logic
This invention relates to a suitable circuit configuration when using the Injection Logic (hereinafter abbreviated as 2L) process.

This 2L process does not require any element isolation, making it possible to make load elements very small, and requires fewer masks, and requires only about half the manufacturing steps compared to a normal IC process. Since it can be manufactured, its price is very low.

Furthermore, this 2L process is characterized in that the size of the IC chip is reduced because it is constructed so that current is injected from the PNP transistor to each other transistor.

First, the basic principle of the hysteresis circuit of the present invention will be explained below with reference to FIG.

1 is the first transistor, 2 is the second transistor, 3
is a third transistor and 4 is a fourth transistor, all of which have emitter grounding, and are connected in cascade in order.

That is, the collector of the first transistor 1 is connected to the base of the second transistor 2, the collector of the second transistor 2 is connected to the base of the third transistor 3,
The collector of the third transistor 3 is connected to the base of the fourth transistor 4, and the collector of the fourth transistor 4 is further connected to the base of the first transistor 1.

10 is a current source that supplies an input current, from which the first
An input current is supplied to the base of transistor 1 of .

A first current source 5 is connected between the collector of the first transistor 1 and the power source B, and supplies a constant current 11 to the first transistor 1.

A second current source 6 is connected between the collector of the second transistor 2 and the power source B, and supplies a constant current 2 to the second transistor 2.

A third current source 7 is connected between the collector of the third transistor 3 and the power source B, and supplies a constant current 3 to the third transistor 3.

Further, 8 and 9 are diodes, respectively, which are connected between the base and emitter of the first transistor 1 and between the base and emitter of the fourth transistor 4.

The diode 8 and the transistor 1 and the diode 9 and the transistor 4 each constitute a current mirror circuit.

By the way, here, constant current ■1. ■2 and I3 first,
The second and third current sources are used to supply the constant current. ■2. ■3 may be set.

Next, the operation of the above-mentioned hysteresis circuit will be explained in detail with reference to FIG.

In Figure 2, the horizontal axis represents the input current supplied to the base of the first transistor 1, and the vertical axis represents the currents flowing through the first, second, and third transistors 1, 2, and 3, and the hysteresis circuit is This shows the current characteristics.

That is, when the input current supplied from the current source 10 is O, the first transistor 1 is off, the second transistor 2 is on, and the third transistor 3 is off.
A current supplied from the third current source 7 flows through the diode 9, and the current flowing through the diode 9 and the current flowing through the collector of the fourth transistor 4 are set to be equal.

Then, the input current Iin from the current source 10 gradually increases along the curve 20, and the first transistor 1 continues to remain off until Iin reaches the current ■3 flowing to the collector of the transistor 4. It is.

Then, when Iin''I3 at time t1, the first transistor 1 turns on for the first time, and the input current Iin
When Iin gradually decreases, it remains on even when Iin becomes equal to 13, but it turns off only when Iin becomes equal to 11 at time t2.

Therefore, the voltage waveform appearing at the collector of the first transistor 1 changes as shown in FIG. 3, and has current hysteresis characteristics.

Therefore, from the current sources 5, 6, 7, the first transistor 1,
Current supplied to the collectors of the second transistor 2 and the third transistor 3 ■1. ■2. If (1) 3 is determined by an external resistor (not shown), the current value of the hysteresis characteristic shown in FIG. 3 is extremely stable.

As a specific application example, the hysteresis circuit of the present invention can be configured as an oscillator as shown in FIG. 4, for example.

In the following, this oscillator will be explained, and parts corresponding to those in FIG. 1 will be described with the same reference numerals.

That is, grounded emitter transistors 1, 2, and 3 are connected in cascade, and their respective collectors are connected to a plurality of collectors of multi-collector transistors 25 serving as current sources 5, 6, and 7, respectively.

The base of the transistor 25 is grounded, and the emitter is connected to the power supply 1B via a current source 28, and the transistor 25 is connected to the first transistor 1 and the second transistor 2.
, a constant current is supplied to the collector of the third transistor 3.

The collector of the third transistor 3 is connected to the collector of the transistor 21 corresponding to the diode 9 in FIG. 1, and also to its base, and its emitter is grounded.

Further, the base of the transistor 21 is connected to the base of the transistor 22 corresponding to the fourth transistor 4 in FIG. is connected to the base of the first transistor 1.

The transistor 24 is provided corresponding to the diode 8 shown in FIG. is grounded.

The coil 27 is connected to a power source 1B via a resistor 26, also an oscillation element, which is connected in series with the coil 27, and its connection midpoint is connected to the collector of the transistor 23, and its emitter is grounded.

Here, the first transistor 1 and the diode-connected transistor 24 constitute a current mirror circuit, and the transistor 22 corresponding to the fourth transistor and the diode-connected transistor 21 also constitute a current mirror circuit. It is configured.

Next, the operation of this oscillator will be explained with reference to FIGS. 5 and 6.

Figure 5 shows the coil 27 as the oscillation element in Figure 4.
6 is a waveform diagram of the current IL flowing in the transistor 23, and FIG. 6 is a collector voltage waveform diagram of the transistor 23.

This current IL gradually increases along the curve 30; time t1
When the current becomes equal to the current 3 supplied to the collector of the third transistor 3, the transistor 1 changes from off to on, and thereby the transistor 23 similarly changes from off to on.

Next, when the current IL flowing through the coil 27 gradually decreases along the curve 30, the transistor 23 remains on until reaching time t2, and at time t2, the current IL changes to the current ■1 flowing through the first transistor 1. When they become equal, the transistor 23 is turned off.

Thereafter, when the current IL gradually increases along the curve 30, the transistor 23 is turned on at time t3, and the current I
Current 1 flowing through the first transistor 1 as L gradually decreases
Transistor 23 remains on until it becomes equal to 1.

Therefore, assuming that the elapsed time between time t□ and t2 is To and the elapsed time between time t2 and t3 is T2, an oscillation output signal with a period of T2T1+T2 is obtained at the collector of the transistor 23.

Also, the reactance of the coil 27 as an oscillation element is L.
1 The current flowing through the first and third transistors 1 and 3 is 1
1. I3, the voltage of power supply element B is set to vcc1 transistor 24
If the base-emitter voltage of is Vbe, the oscillation frequency f is expressed by the following equation (1).

Furthermore, the hysteresis circuit of the present invention can also constitute an oscillator using a coil and a resistor as oscillation elements, as shown in FIGS. 7 and 8.

That is, the circuit shown in FIG. 7 is the same as the circuit shown in FIG. After dividing the voltage by resistor 26 and resistor 32 and lowering it, coil 2
7 and transistor 23.

With this configuration, Vcc is lowered in the above-mentioned equation (1), so that the influence of Vbe on the oscillation frequency can be reduced.

Note that in this case, the power supply voltage was lowered by dividing it using resistors, but this may be done by simply lowering the power supply voltage, and in this case, the effect of Vbe on the oscillation frequency is can be reduced.

In addition, the circuit shown in FIG. 8 is the circuit shown in FIG.
A Zener diode 33 is connected in series with the transistor 7, and the other end of the Zener diode 33 is connected to the collector and base of the transistor 24.

With this configuration, the Zener diode 3
3, where Vz is the voltage across Vz and Vz>Vbe, the oscillation frequency f is expressed by the following equation (2).

Then, by selecting various Zener diodes 33 and setting Vz, the conduction angle of the oscillation output signal can be increased.

Further, the base-emitter voltage Vbe of the transistor 24
If the characteristics of the Zener diode 33 are selected to compensate for the temperature characteristics of the oscillator, the oscillation frequency of this oscillator can be freed from the influence of the temperature characteristics.

Furthermore, the hysteresis circuit of the present invention can also constitute an oscillator using resistors and capacitors as oscillation elements, as shown in FIG.

That is, in this case, the resistor 26 and the capacitor 34 are connected in series between the power supply element B and the ground, and the midpoint of the connection is directly connected to the collector of the transistor 23, and the resistor 3
5 to the base of transistor 1.

With this configuration, the first transistor 1
, the second transistor 2, and the third transistor 3, and the output is fed back to the first transistor 1 through the resistor 26, 35 and the capacitor 34, thereby forming an oscillator.

Therefore, the collector voltage of the transistor 23 changes with the period of time T1 as shown in FIG. 10, and this is taken out as an oscillation output.

Here, the capacitance of the capacitor 34 is set to C1 resistor 2'6゜3.
The resistance values of 5 are R1 and R2, the voltage of power supply element B is Vcc1, the current flowing through the first transistors 1 and 3 is 11 and 3
Then, the period T of the oscillation output signal ν shown in FIG.
is expressed by the following equation (3).

Furthermore, the hysteresis circuit of the present invention can also constitute a monostable multivibrator using resistors and capacitors as oscillation elements, as shown in FIG.

That is, in this case, in the circuit shown in FIG. 9, one collector of the transistor 22 is connected to a trigger input terminal 37 via a resistor 36, and a square wave trigger pulse 38 is supplied from this terminal 37. are doing.

Next, the waveform of the current I flowing through the resistor 26 in this circuit is shown in FIG. 12, the trigger pulse 38 is shown in FIG. 13, and the collector voltage waveform of the transistor 23 is shown in FIG. 14.

That is, when the trigger pulse 38 is supplied to the terminal 37 between times t1 and t2, an output pulse voltage can be obtained at the collector of the transistor 23 between times t0 and t3 due to the hysteresis characteristics of this circuit. be understood.

The oscillator and the like to which the above-described hysteresis circuit of the present invention is applied have the following various features.

First of all, when manufactured using the 2L process, it can be manufactured in about half the manufacturing steps, which is much fewer than that of a normal IC process, so the price is very low.

Furthermore, since the power supply voltage can be selected low, it can be used with low power.

Furthermore, since the number of external parts can be reduced, the oscillation frequency determined thereby can be made highly stable.

Thus, according to the hysteresis circuit of the present invention, the first, second, third and fourth grounded emitter transistors are connected in cascade in order, and the collectors of the first, second and third transistors are connected to ．． When the current sources of I2 and I3 are connected and the collector of the fourth transistor is connected to the base of the first transistor.

In both cases, diodes were connected between the base and emitter of the first and fourth transistors, respectively, so that the input current was supplied to the base of the first transistor, so when manufactured using the 2L process, Particularly effective for easy circuit configuration and low power use.

It is possible to operate with high stability.

Furthermore, when the hysteresis circuit of the present invention is applied to an oscillator using a resistor, a coil, and a capacitor as oscillation elements, the oscillation frequency determined by this can be made highly stable because the number of external parts can be reduced. Can be set to .

Furthermore, even when the hysteresis circuit of the present invention is applied to a monostable multi-bibreak, the circuit structure can be simplified and highly stable operation can be achieved.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing the basic configuration of the hysteresis circuit of the present invention, Figs. 2 and 3 are waveform diagrams for explaining the operation of Fig. 1, and Fig. 4 is a circuit diagram of an oscillator to which the hysteresis circuit of the present invention is applied. , FIGS. 5 and 6 are waveform diagrams for explaining the operation of FIG. 4, FIGS. 7, 8, and 9 are circuit diagrams of an oscillator to which the hysteresis circuit of the present invention is applied, and FIG. 10 is a waveform diagram for explaining the operation of FIG. Figure 9 is a waveform diagram for explaining the operation, Figure 11 is a circuit diagram of a monostable multivibrator to which the hysteresis circuit of the present invention is applied, and Figures 12, 13 and 14 are for explaining the operation of Figure 11. FIG. L2, 3 and 4 are first, second, third and fourth emitter grounded transistors, 5, 6 and 7 are first, second and third current sources, and 8 and 9 are diodes.

Claims (1)

[Claims] 1 First, second, third, and fourth emitter grounded transistors are connected in cascade in order, and currents of 1°I2 and I3 flow through the collectors of the first, second, and third transistors, respectively. , the second and third current sources are connected, the collector of the fourth transistor is connected to the base of the first transistor, and a diode is connected between the base and emitter of the first and fourth transistors, respectively. a hysteresis circuit connected to the base of the first transistor such that an input current is supplied to the base of the first transistor;