JP2605705Y2 - Membership function circuit - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membership function circuit used in a sweep type fuzzy computer for executing fuzzy inference.

[0002]

BACKGROUND OF THE INVENTION In fuzzy research, linguistic information generally has ambiguity, vagueness, uncertainty, incompleteness or accuracy and is characterized by membership functions. The size of this membership is between 0.0 and 1.0
It is represented by the numerical value of the area between and varies within this range.

FIG. 4 is a block diagram showing a conventional membership function circuit which outputs a signal representing a membership function in a fuzzy proposition and synchronized with a sweep signal.

The membership function circuit receives, for example, a sweep voltage V _{S of a} triangular wave and a label voltage _VL of a constant value to input a Z function signal (a change in the sweep voltage V _S with a change point near the label voltage _VL ). A Z-function circuit 1 for generating a signal that changes between a maximum value and a minimum value in a substantially inverse proportion.
Similarly enter the sweep voltage V _S and the label voltage V _L S
And S function circuit 2 for generating a function signal (signal that varies between a maximum value and a minimum value substantially proportional to the change in the sweep voltage V _S to the vicinity of the label voltage V _L as a change point), both function circuit 1, And a MIN operation circuit 3 which receives the output voltage of No. 2 and outputs the smaller voltage as a membership function signal.

FIG. 5 is a circuit diagram which embodies the membership function circuit. Transistor Q connected differentially
1, Q2, current mirror connected transistors Q3 and Q4 for transferring the collector current of transistor Q1, diode connected transistor Q5, resistors R1 to R3, switch SW1, and constant current sources 4 and 5 for current Io are shown in FIG. The S function circuit 2 shown is configured.

[0006] In a state of turning on the switch SW1, upon application of a sweep voltage V _S of the triangular wave to the base of transistor Q1, than the label voltage V _L constant value that sweep voltage V _S is applied to the base of transistor Q2 While sufficiently low, that is, while V _S << V _L , the transistor Q1 is turned off and the transistor Q2 is turned on, and the current Io of the constant current source 4 flows as the collector current I _CQ2 of the transistor Q2.

However, when the voltage V _S rises and approaches the voltage V _L and reaches V _S = V _L -R1 · Io, the collector current of the transistor Q1 starts to flow, and the collector current of the transistor Q2 is correspondingly increased. When the current starts to decrease and the sweep voltage V _S rises to V _S = V _L , the transistor Q
2 turns off, Q1 turns on, and the collector current I _CQ1 of the transistor Q1 becomes Io.

The collector current I _CQ1 of the transistor Q1 that changes as described above is transferred by the current mirror including the transistors Q3 and Q4, and is converted into the S function voltage V _X1 by the load resistor R2. The above operation waveforms are shown in FIGS.

When the switch SW1 is turned off, the collector current I _CQ1 of the transistor Q1 increases from the time when the sweep voltage V _S becomes lower than the label voltage V _L by the base-emitter voltage V _{BEQ5 of the} transistor Q5. Starts. That is, the characteristic of the voltage V _X1 shifts to the left as indicated by the dashed line in FIG. 6B.

On the other hand, the differentially connected transistors Q6,
Q7, transistors Q8 and Q9 of current mirror connection for transferring the collector current of transistor Q6, transistor Q10 diode-connected, resistors R4 to R6, switch SW2, and constant current sources 6 and 7 for current Io are shown in FIG. The Z function circuit 1 is configured.

[0011] In a state of turning on the switch SW2, the application of a sweep voltage V _S of the triangular wave to the base of transistor Q7, than the label voltage V _L constant value that sweep voltage V _S is applied to the base of the transistor Q6 While sufficiently low, that is, while V _S << _VL , the transistor Q6 is turned on and the transistor Q7 is turned off, and the current Io of the constant current source 6 flows as the collector current I _CQ6 of the transistor Q6.

However, when the voltage V _S rises and approaches the voltage V _L and reaches V _S = V _L , the collector current of the transistor Q7 starts to flow, and the collector current of the transistor Q6 correspondingly decreases. At first, when the sweep voltage V _S rises to V _S = V _L + Io · R4, the transistor Q
6 turns off, Q7 turns on, and the collector current I _CQ7 of the transistor Q7 becomes Io.

The collector current I _CQ6 of the transistor Q6 which changes as described above is transferred by the current mirror composed of the transistors Q8 and Q9, and is converted into the Z function voltage V _X2 by the load resistor R5. The above operation waveforms are shown in FIGS. 6 (c) and 6 (d).

When the switch SW2 is turned off, the collector current I _CQ6 of the transistor Q6 decreases from the time when the sweep voltage V _S becomes higher than the label voltage V _L by the base-emitter voltage V _{BEQ10 of the} transistor Q10. Starts. That is, the characteristic of the voltage V _X2 shifts to the right as shown by the dashed line in FIG.

Next, the transistors Q11 to Q13 and the resistors R7 and R8 constitute the MIN operation circuit 3 in FIG. 4, wherein the smaller one of the S function voltage V _X1 and the Z function voltage V _X2 is selectively used. Is done.

That is, as the S-function voltage V _X1 becomes smaller, the transistor Q11 increases the collective current and causes a corresponding voltage to be generated in the resistor R7.
As the function voltage V _X2 decreases, the collector current increases and a corresponding voltage is generated in the resistor R7. The voltage obtained by inverting the voltage generated at the resistor R7 is applied to the transistor Q3.
Appears as a membership function voltage V _{OUT at} the emitter resistance R8 of the IGBT.

The voltage V _OUT has a triangular waveform as shown by a solid line in FIG. 6E or a trapezoidal waveform as shown by a dashed line when the switches SW1 and SW2 are turned off.

A current Io flowing from the constant current sources 5 and 7 flows through the resistors R3 and R6 (= R3).
3, causing a voltage drop of the same value of Io R8, thereby lowering the base voltage of the transistor Q2 from the label voltage _VL by Io R3,
Is raised from the label voltage V _L by Io · R6.

The voltages Io.R3 and Io.R6 compensate the base-emitter voltages of the transistors Q2 and Q6,
This is to prevent the peak value of the membership function voltage shown in FIG. 6E from dropping below Io · R2 (or Io · R5).

[0020]

However, in such a membership function circuit, the signals obtained by the S function circuit 2 and the Z function circuit 1 are converted into a voltage signal V by current / voltage conversion.
_X1 and _VX2 , then processed by the MIN operation circuit 3, and further subjected to current / voltage conversion at the output stage to output voltage V
Since it is extracted as _OUT , a special MIN operation circuit 3 is required, which not only increases the circuit scale, but also requires an extra current for charging / discharging the parasitic capacitance at the time of current / voltage conversion in the intermediate stage and the final stage. There is a problem that the response speed is reduced and the current consumption is increased, which is not suitable for integration into an integrated circuit.

An object of the present invention is to reduce the circuit scale,
In addition, it is an object of the present invention to provide a membership function circuit which solves the above problem by realizing high speed operation with low current consumption.

[0022]

SUMMARY OF THE INVENTION For this purpose, the present invention relates to a Z
A membership function circuit comprising a function circuit and an S function circuit, wherein the Z function circuit is applied via a forward connection diode to a emitter and a base of a first transistor to which a sweep voltage is applied to a base. The first and second constant current sources are connected to the respective emitters of the first and second transistors by connecting the emitters of the second transistors via a first resistor. A first current mirror circuit for extracting a collector current is connected to the S function circuit, and the label is connected in reverse to the emitter of the third transistor to which the sweep voltage is applied to the base and the diode connected in the reverse direction to the base. The emitter of the fourth transistor applied via the second transistor is connected via a second resistor, and the emitters of the third and fourth transistors are connected. And a third and a fourth constant current source whose total current value is equal to the total value of the currents of the first and second constant current sources, and a second transistor for extracting the collector current of the third transistor. Connect and configure the current mirror circuit,
The collector of the output-side transistor of the first current mirror circuit and the collector of the output-side transistor of the second current mirror circuit are commonly used as an output terminal. The other end is connected, a bias constant current source for conducting the forward connection diode and the reverse connection diode is provided, and a membership function voltage is extracted from the output terminal.

[0023]

Embodiments of the present invention will be described below.
FIG. 1 is a block diagram of the membership function circuit of the present invention. In the present invention, the sweep voltage V _S and the label voltage V _L
Are input to the Z function circuit 11 and the S function circuit 12, respectively, and the outputs of the function circuits 11 and 12 are connected in a wired OR circuit to obtain a membership function signal.

FIG. 2 is a specific circuit diagram of the membership circuit. First, the Z function circuit 11 includes transistors Q21 and Q22 that are differentially connected via a resistor R11, transistors Q23 and Q24 that are current mirror-connected to transfer the collector current of the transistor Q21, and collector currents of the transistors Q24 and Q22. , That is, the current mirror-connected transistors Q25 and Q25 for taking out the collector current of the transistor Q22.
26, current mirror-connected transistors Q27, Q28 which transfer the collector current of the transistor Q26,
The differential pair includes constant current sources 13 and 14 for current Io connected to the emitters of the transistors Q21 and Q22, a diode-connected transistor Q29, a resistor R12, and a current source 15 for current Io.

The S function circuit 12 includes transistors Q30 and Q31 differentially connected via a resistor R13, transistors Q32 and Q33 which are current mirror-connected to transfer the collector current of the transistor Q30, and the transistors Q33 and Q31. Of the collector currents of the transistors Q34, Q
35, current mirror-connected transistors Q36, Q37 that transfer the collector current of the transistor Q35,
The differential pair includes constant current sources 16 and 17 for the current Io connected to the emitters of the transistors Q30 and Q31, a diode-connected transistor Q38, a resistor R14, and a current source 18 for the current Io.

[0026] Then, collectors of the transistor Q37 of the transistors Q28 is directly connected so as to constitute a wired OR circuit, the resistor R15 between the reference voltage source voltage here and V _REF is applied are connected.

Now, the current Io flowing from the constant current sources 15 and 18 causes the diode-connected transistors Q29 and Q3
Since 8 is conducting always biased, the base of transistor Q22 is applied a low voltage by V _BEQ29 than the label voltage V _L, higher by V _BEQ38 than the label voltage V _L to the base of the transistor Q30 voltage Is applied. The values of the resistors R12 and R14 are negligible, and the voltage drop here is negligible.

In the Z function circuit 11, the sweep voltage V
_{While S} is V _S <(V _L −V _BEQ29 ), the transistor Q21 is turned off and the transistor Q22 is turned on, and the state where the collector currents of the transistors Q22 and Q25 to Q28 are 2Io continues.

The increased sweep voltage V _S is, V _S = to consist (V _L -V _BEQ29) to _{V S> (V L -V BEQ29} ), the transistor Q22 with the collector current of the transistor Q21 begins to increase The collector current starts decreasing, and the collector currents of the transistors Q25 to Q28 also start decreasing, and after a predetermined time, the collector current becomes zero.

[0030] After this, move to decline sweep voltage V _S is beyond the peak value, the transistor Q21 drops to a value off, transistor Q22 is turned on, the transistor Q22, the collector current of Q25~Q28 is 2I
It becomes o.

The above operation is repeated according to the change in the sweep voltage V _S , and the collector current I _CQ27 of the transistor Q27 has a current characteristic having an intermittent trapezoidal waveform as shown in FIG. .

As described above, the time from when the collector current I _CQ27 of the transistor Q27 starts decreasing from 2Io to 0, and the time when it increases from 0 to 2Io, that is, the current decreasing / increasing characteristic. The slope is determined by the value of the resistor R11. The larger the value, the steeper the slope, and the smaller the value, the slower the slope.

On the other hand, in the S function circuit 12, while the sweep voltage V _S is V _S << V _L , the transistor Q30 is turned on, the Q31 is turned off, and the collector currents of the transistors Q31 and Q34 to Q37 are zero.

When the sweep voltage V _S increases, the collector current of the transistor 31 starts increasing at a certain point,
The collector current of transistor Q30 starts to decrease.
When the voltage increases to V _S = (V _L + V _BEQ38 ), the transistors Q31, Q34 to Q3
7 becomes 2Io, and the transistor Q30
Becomes zero.

Thereafter, even if the sweep voltage V _S increases, the collector currents of the transistors Q31 and Q34 to Q37 become 2
Although it does not change from Io, when the voltage drops again to V _S = (V _L + V _BEQ38 ) and this downward trend continues, the collector current of the transistor Q31 starts to decrease, and conversely, the collector current of the transistor Q30 increases. Starting, after a predetermined time, the collector current of the transistor Q31 becomes 0.

The above operation is repeated according to the change in the sweep voltage V _S , and the collector current I _CQ36 of the transistor Q36 has a current characteristic having an intermittent trapezoidal waveform as shown in FIG. .

As described above, the time from when the collector current of the transistor Q36 starts increasing from 0 to 2Io and the time from when the collector current starts to decrease from 2Io to 0Io, that is, the current decrease / increase characteristics Of the resistance R
The value is determined by the value of 13. The larger the value, the steeper the slope, and the smaller the value, the slower the slope. If the values of the resistors R13 and R11 are set to the same value, the slope of the current increase / decrease in the characteristic diagrams shown in FIGS. 3B and 3C becomes the same.

As described above, the collector current I _CQ28 of the transistor Q28 and the transistor Q
37 Koretaku current I _CQ37 flows, the output voltage V at that time
_OUT is represented by V _OUT = V _REF -R15 ( _ICQ28 + _ICQ37 ).

As shown in FIGS. _3B and _3C , the collector currents I _CQ28 and I _CQ37 are set so that these currents alternately flow at different timings (so as not to overlap). As a result, when the output voltage V _OUT is represented by the sweep voltage V _S , the label voltage V _L , and V _BE29 = V _BE38 = V _BE , the output voltage V _OUT at the rising time, that is, (V _S −V _L ) ≦ −V _BE When V _OUT = V _REF + (V _S −V _L ) R15 / R11 at the maximum, ie, −V _BE ≦ (V _S −V _L ) ≦ V _BE , V _OUT = V _REF falling, that is, (V _S − V _L ) ≧ V _BE satisfies V _OUT = V _REF − (V _S −V _L ) R15 / R13. Each of the _{values is in} the range of 0 ≦ V _OUT ≦ V _REF .

If the capacitance between the collector and base of the transistors Q28 and Q37 is sufficiently small, the delay due to the transient response between these capacitances and the resistor R15 can be reduced, and the collector currents I _CQ28 and I _CQ37 can be increased. Therefore, it is possible to realize a fast response speed with low power consumption.

In the conventional example shown in FIG. 5, the Z function circuit 1
In order to obtain the output of the S function circuit 2, a current / voltage conversion unit is required, and operation delay and power consumption occur therein. In this embodiment, the Z function circuit 11 and the S function circuit 12
The current / voltage conversion unit is not required there, and there is no problem of power consumption or operation delay there.

Since the voltage V _REF is used as a reference,
When an integrated circuit is formed, the maximum value of the output voltage is not affected by variations in the value of the resistance element inside the circuit.

[0043]

As described above, according to the present invention, the current mode in which the outputs of the Z function circuit and the S function circuit are taken out as currents and the currents are added in a wired-OR manner, so that the conventional MIN operation circuit is added thereto. Is not necessary, and the circuit scale can be reduced. Further, the current / voltage converter is only the final output stage, and high-speed operation with low power consumption can be realized. Further, the maximum value of the output voltage is not affected by the variation in the value of the internal resistance element.

[Brief description of the drawings]

FIG. 1 is a block diagram of a membership function circuit of the present invention.

FIG. 2 is a specific circuit diagram of the circuit.

FIG. 3 is a waveform chart showing operation characteristics of the circuit.

FIG. 4 is a block diagram of a conventional membership circuit.

FIG. 5 is a specific circuit diagram of the circuit.

FIG. 6 is a waveform chart showing operation characteristics of the circuit.

Claims (1)

(57) [Scope of request for utility model registration] 1. A membership function circuit comprising a Z function circuit and an S function circuit, wherein the Z function circuit comprises: a first transistor having a base to which a sweep voltage is applied; The emitter of the second transistor applied via the connection diode is connected via a first resistor and the first and second emitters are connected to the respective emitters of the first and second transistors.
And a first current mirror circuit for extracting a collector current of the second transistor is connected to the S-function circuit, and the S transistor is applied to a base of the third transistor. The label voltage is applied to the emitter and the base of the fourth through a reverse connection diode.
Are connected via a second resistor, and the total current value of each of the emitters of the third and fourth transistors is equal to the total value of the currents of the first and second constant current sources. A third current mirror circuit connected to the third and fourth constant current sources, and a second current mirror circuit for extracting a collector current of the third transistor connected to a collector of an output transistor of the first current mirror circuit; The collector of the output-side transistor of the second current mirror circuit is commonly used as an output terminal, the other end of a resistor to which a reference voltage is applied to one end is connected to the common connection point, and the forward connection diode and the reverse connection are connected. A membership function circuit, comprising: a bias constant current source for conducting a direction connection diode; and extracting a membership function voltage from the output terminal.