JPS5922599Y2 - Broken line output device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fold line output device, and its purpose is to improve the output resistance of the conventional fold line output unit to a low output resistance.

FIG. 1 shows a circuit diagram of an example of a conventional broken line output device.

In the figure, 1 is an input terminal to which input voltage Ex is applied;
R1-R3 are resistors, Dl and D2 are diodes, Es is a reference voltage, Ul is an amplifier, and 2 is an output terminal from which the output voltage 0 is taken out.

Input voltage Ex applied to human blade terminal 1 in this device
When the voltages are −, L, ES, and rear negative, the diode D2 is turned on, and current flows from the output of the amplifier U1 to the diode D2 and then to the resistor &, and a positive output voltage Vo is generated.

As shown in FIG. 2, this output voltage Vo increases as the input voltage Ex becomes more negative.

In the above case, the output resistance of the output terminal 2 is a very small value because the diode D2 is on.

Next, when the hydraulic voltage Ex is more positive than 11 cm.Es, the diode D1 is turned on and the diode included is turned on.

Since the output terminal 2 is connected to the virtual ground point which is the input terminal of the amplifier U1 via the resistor R3, the output voltage vO is Ov.

At this time, the output resistance of the output terminal 2 is R3, but since the resistance R3 is generally a relatively high resistance, leakage current may flow into the output terminal 2, or the output resistance of the next stage amplifier etc. connected to the output terminal 2 may be affected. If a bias current or the like flows into the resistor R3, the output terminal 2 becomes O.
It produces a voltage at a level of , not v.

The voltage generated at the output terminal 2 due to this leakage current is
It changes depending on the magnitude of leakage current, etc., and causes an undesirable phenomenon as a broken wire output device.

The present invention has been made in view of this point.

FIG. 3 shows an embodiment of the present invention.

In FIG. 3, 1 is an input terminal to which an input voltage Ex is applied, R1-R5 are resistors, Ul is an amplifier, Ql is a PNP transistor, Es is a reference voltage, and 2 is an output terminal from which an output voltage VO is taken out.

Input terminal 1 is connected via resistor R1 to the inverting input terminal of amplifier U1.

This inverting input terminal is connected to circuit ground (reference circuit voltage) via a series circuit of resistor R2 and reference voltage Es, and the non-inverting input terminal of amplifier U1 is connected to circuit ground.

The output terminal of amplifier U1 is connected to the base of transistor Q1 via resistor R4, the emitter of transistor Q1 is connected to circuit ground, and the collector is connected to the inverting input terminal via resistor R3 and resistor R5. It is connected to the positive power supply Vc through the power supply Vc.

That is, when a PNP transistor, for example, is used as the transistor Q1, the emitter is grounded and the collector is connected to a positive power supply, which is a so-called reverse connection configuration.

The operation of the apparatus shown in FIG. 3 configured and connected in this manner will be described below.

In Fig. 3, the input voltage Ex applied to input terminal 1
When the voltage is more negative than ES, the current If flowing through the resistor R3 flows from the output side to the input side.

Therefore, the output voltage Vo of the output terminal 2 becomes a positive voltage represented by R3·■.

At this time, the amplifier U1 supplies the base current Ib□ of the transistor Q1 so that the voltage at the inverting input terminal becomes a virtual ground potential, that is, 0□.

Transistor Q that is reversely connected (for example, a positive power supply is connected to the collector in a PNP transistor with a common emitter)
1 collector-emitter voltage V.

The relationship between E and collector current C1 is as shown in FIG. 5, and the rising characteristic from the origin in the graph is steeper than that of normal forward connection.

Assuming that the load line of the transistor is 1 as shown in FIG. 5, the operation of the transistor is determined by the intersection of the load line 1 and the base current Ibl at this time.

Amplifier U1 has collector-emitter voltage ■.

The base current Ibl of the transistor Q1 is controlled so that E=R3·If.

As the input voltage Ex increases towards Es, the current flowing through the resistor 2 R3 decreases, resulting in the output voltage Vo
decreases.

That is, the base current Ibl of the transistor Q1, which is the output of the amplifier U1, increases, and as a result, the collector-emitter voltage ■.

, also decreases, the current ■, becomes small, and the voltage at the inverting input terminal of the amplifier U1 maintains O■.

When the input voltage Ex further increases, the base current I5□ of the transistor Q1, which is the output of the amplifier U1, increases, and the fifth
It reaches Pl in the figure.

That is, the output voltage V of the device shown in FIG. 3 at this time. becomes the voltage V1 shown in FIG. 5, but since the collector and emitter of the transistor Q1 are reversely connected, as mentioned above, the rise from the origin is steep in the graph of FIG.
The voltage v1 can be regarded as O (actually less than a few IQmV).

The value of the input voltage Ex at this time is -, Na.Es.

Next, the input voltage Ex increases and becomes more positive than Ikkuroto Es2, and the amplifier U1 further increases the base current ■5□ of the transistor Q, which is its output.
1 collector-emitter voltage■.

As is clear from FIG. 5, E cannot be smaller than the voltage (1), and the voltage (2).

, maintains O■. Therefore, at this time, the potential of the inverting input terminal of the amplifier U1 is not a virtual ground potential but a positive potential.

In this way, the output voltage Vo of the device shown in FIG. 3 obtains a broken line characteristic similar to that of the device shown in FIG. 1, as shown in FIG.

Also, the output resistance at the output terminal 2 of this device in Fig. 3 is r
.

, the collector current of the transistor Q1 is C1, the output resistance ro is expressed by equation (1).

One-! L(1) r〇-■c1 Therefore, when the output voltage Vo is O■, the output resistance r.

Even if a leakage current or the like flows into the output terminal 2 from the outside, it does not affect the output voltage Vo in any way and maintains O■.

FIG. 6 is a diagram showing another embodiment of the present invention.

The difference between the device in FIG. 6 and the device in FIG. 3 is that instead of the PNP transistor Q1 in the device in FIG.
A PN transistor Q2 is connected, and in the device shown in FIG. 3, a resistor R5 is connected to a positive power supply V.

In contrast to the device shown in FIG. 6, the resistor R5 is connected to the negative power source vE.

However, the device of FIG. 3 and the device of FIG. 6 are the same in that the transistor Q2 is reversely connected (that is, in this case, the emitter of the NPN transistor Q2 is grounded and the collector is connected to the negative power supply).

Other than that, the configuration is exactly the same as that of the device shown in FIG. 3, and the same component numbers as in FIG. 3 are given, and explanations of the configuration and connections will be omitted.

In Fig. 6, when the input type pressure Ex applied to the input terminal 1 is a positive voltage than 11 in.Es, the current f flowing through the resistor R3 flows from the inverting input terminal side to the output terminal 2 side, and therefore The output voltage Vo at output terminal 2 is R3・■
, a negative voltage is generated.

In this case, the base current 1 of the transistor Q2 flows in the opposite direction to that of the device shown in FIG. The transistor Q2 operates to control the base current Ib2 of the transistor Q2.

As the input voltage Ex decreases, the base current Ib2, which is the output of the amplifier Ul, increases and reaches Pl in FIG.

However, in this case, since the collector power supply V is negative, it is clear that the polarities of the coordinates in FIG. 5 can be reversed and read.

From FIG. 5, as mentioned above, even if the output voltage Vo becomes O■ and the input voltage Ex further changes to negative,
The output voltage Vo maintains 0■.

As described above, the output voltage Vo of the device shown in FIG. 6 has the broken line characteristic shown in FIG.

In this case, as in the device shown in FIG. 3, when the output voltage vO is 0, the output resistance r.

is OΩ as shown in equation (1), and even if a leakage current or the like flows into the output terminal 2, the output voltage Vo maintains 0■ and is not affected by the nok current or the like.

In addition, in the device shown in FIG. 3 and the device shown in FIG.
By changing the magnitude of the reference voltage Es, or by changing the polarity of the reference voltage Es, or by changing the values of the resistors R1 and R2, the input terminal E
It is clear that a broken line characteristic can be obtained at any voltage of x.

FIG. 8 shows a device that can obtain the same broken line characteristic as in FIG. 4 by using an amplifier operated with a single power supply.

In FIG. 8, amplifier U2 has one of its power supplies connected to a positive power supply V.

and the other to circuit ground.

Input voltage Ex is applied from input terminal 1 via resistor R1 to the inverting input terminal of amplifier U2, and reference voltage Es is further applied via resistor R2.

The other end of the reference voltage Es is connected to circuit ground.

Further, a resistor R3 is connected between the input and output terminals of the amplifier U2, and the non-inverting input terminal is connected to circuit ground.

In the device shown in FIG. 8 configured and connected in this way, when the input voltage Ex becomes a voltage more negative than Es, the current flowing through the resistor R3 flows from the output side of the amplifier U2 toward the inverting input terminal side. Flow output terminal 2 has R3.
A positive voltage of If is generated.

Next, as the input voltage Ex increases and approaches 1 yen).Es, the current I decreases, and the output voltage Vo of the amplifier U2 decreases and approaches the circuit ground potential.

If you use an amplifier whose output amplitude can reach the voltage of the power supply to the amplifier as amplifier U2, that is, in this case, if you use an amplifier whose output amplitude can reach the circuit ground potential, the input voltage Ex will be more than -, Es. At a voltage of , the output voltage Vo of the amplifier U2 becomes O■.

Therefore, the output voltage Vo of the output terminal 2 can have a broken line characteristic similar to that shown in FIG.

Figure 9 shows a combination of several fold line output devices according to the present invention.
10 is a diagram showing a device for obtaining an arbitrary broken line curve as shown in FIG. 10 by adding the outputs using an adder. FIG.

In FIG. 9, B1 to BK are broken line output devices according to the present invention.

Input terminal 3 includes resistor R6, wire output device B1 and resistor R7.
A series circuit of a broken wire output device B2 and a resistor R8,
Connected in parallel to a series circuit of a broken line output device BK and a resistor BK (K is an arbitrary integer), resistors R6, R7,...RK
are respectively connected to the inverting input terminal of amplifier U3.

The non-inverting input terminal of amplifier U3 is connected to circuit ground;
A resistor R9 is connected between the output of amplifier U3 and the inverting input terminal to configure an adder.

Broken line output device B1. B2. . . . The input voltages at each bending point in BK, that is, the voltages represented by 1, +Es explained in the apparatus of FIG. 3 and the apparatus of FIG. 6, are expressed as El, B2, . ...
If EK, then the output voltage of the device in Figure 9 ■.

As ut, a broken line curve shown in FIG. 10 can be obtained.

As described above, in conventional devices, when leakage current or bias current flows from the output terminal, the zero level of the output voltage is affected, but according to the present invention, the transistor used in the output stage are reversely connected, the voltage between the collector and emitter is so small that it can be approximately regarded as O■, and as a result, the output resistance can be regarded as OΩ, so even if leakage current etc. flows into the output terminal, the output voltage will not change. The zero level of does not change.

Therefore, when the apparatus of the present invention is used to construct an apparatus for obtaining a broken line curve as shown in FIG. 9, a stable broken line curve can be obtained, and the effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional fold line output device, FIG. 2 is a diagram showing the fold line output characteristics of the device shown in FIG. 1, FIG. 3 is a diagram showing an embodiment of the fold line output device according to the present invention, and FIG. 3 shows the broken line output characteristics of the device, FIG. 5 shows the characteristics of reversely connected transistors, FIG. 6 shows another embodiment of the broken line output device according to the present invention, and FIG. The figures show the broken line output characteristics of the device shown in Figure 6, Figure 8 shows a device that uses a single power supply amplifier to obtain a broken line output, Figure 9 shows a device that outputs a broken line curve, and Figure 9 shows a device that outputs a broken line curve. FIG. 10 is a diagram showing the output characteristics of the device shown in FIG. 9. R1-R5...Resistance, Es...Reference voltage, Ul...Amplifier, Ql...PNP
) transistor, Q2...NPN) transistor.

Claims (3)

[Scope of utility model registration request] (1) An amplifier to which an input terminal and a constant voltage are summed, a transistor whose base is driven by the output of the amplifier and whose emitter is connected to circuit ground, and a transistor connected between the collector of the transistor and the input terminal of the amplifier. 1. A broken line output device comprising a first resistor and a second resistor connected between the collector of the transistor and a power source, wherein the collector and emitter of the transistor are reversely connected. (2) The folded line output device according to claim 1, which is a registered utility model, characterized in that a PNP transistor is used as the transistor, and a positive power source is used as the power source. (3) The folded line output device according to claim 1, which is a registered utility model, characterized in that an NPH transistor is used as the transistor, and a negative power source is used as the power source.