JPS6334350Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a variable resistance circuit that can arbitrarily and accurately adjust the output rise point and its reference level.

A variable resistance circuit that, by operating an operating mechanism such as a stick connected to a movable element of a variable resistor, obtains an electrical output according to the amount of operation of this operating mechanism and sends it to a controlled part. It is often used in the operation parts of various electrical and electronic devices.

By the way, a variable resistance circuit is generally configured to adjust an output that changes depending on the amount of displacement of a movable element of a variable resistor, and transmit the adjusted output to a controlled section.

For example, in a radio control device (hereinafter referred to as a radio control device) that remotely controls a model running object or flying object using radio waves, by operating a stick provided on the transmitter, a variable resistor connected to this stick can be controlled. A movable element of the device is displaced, and a predetermined control section during one cycle of the control of the radio wave,
The so-called channel width is controlled, and a predetermined operation part of the traveling body etc. is controlled according to this channel width.
It is operated according to the amount of displacement of the movable element.

In this case, the amount of displacement of the movable element of the variable resistor and the output of the variable resistance circuit are generally in a predetermined proportional relationship, but depending on the controlled part, the amount of displacement of the movable element may be the set point. While above or below,
The input to the controlled part is set to a predetermined reference level,
For example, there are cases where it is desired to keep it at zero.

For example, in the above-mentioned radio control device, the control signal of one channel (A channel) is mixed with the control signal of another channel (B channel) for control.
So-called mixing operations are often performed,
In this case, it may be necessary to mix the output into the A channel only when the output of the B channel exceeds a set level.

In other words, as shown by the solid line _a1 in Figure 1, when the amount of displacement of the mover is less than _P1 , the output is zero, and after that, the output changes depending on the amount of displacement of the mover. may be required.

As a variable resistance circuit having the characteristics shown by the solid line _a1 in FIG. 1, a circuit as shown in FIG. 2 has been conventionally known.

In other words, the positive and negative power supplies +V and - are connected between the fixed terminals.
V is connected, the movable element P is connected to an operation mechanism (not shown), and the first
The output of the variable resistor VR ₁ , which has the characteristics shown by the broken line b ₁ in the figure, is connected to the clamp circuit CL whose clamp level is adjusted by the variable resistor VR ₂ via the resistor R ₁ .
to be introduced.

Then, _the clamp level VL ₁ is set by _the variable resistor VR ₂ as shown in FIG. The amount is P ₁
In the following region, the output of the variable resistor VR ₁ is fixed at the clamp level VL ₁ .

On the other hand, the final output is the solid line a ₁ in Figure 1.
Since the output is as shown in , the output of the variable resistor VR ₁ is introduced into the operational amplifier OP ₁ , and the offset voltage corresponding to the clamp level VL ₁ is applied to the operational amplifier OP ₁ by the variable resistor VR ₃ . is given to correct the output of this operational amplifier _OP1 to zero level.

Next, the amount of displacement of the movable element P of the variable resistor VR ₁ becomes P ₁ or more, and its output reaches the clamp level VL ₁
, the clamping operation of the clamp circuit CL is released and the output of the variable resistor VR ₁ is connected to the input resistance R ₂
The signal is applied to the operational amplifier _OP1 via the variable resistor VR3, where it is appropriately amplified, shifted by the offset voltage given by the variable resistor _VR3 , and output.

Therefore, the output of this operational amplifier OP ₁ is resistor
This is inverted by an inverting circuit consisting of R ₄ , R ₅ and an operational amplifier OP ₂ , and the output characteristic shown by the solid line a ₁ in FIG. 1 is obtained.

However, in the conventional variable resistance circuit shown in FIG. 2, when trying to change its output characteristics to those shown by the solid line _a2 in FIG. , when changing from P ₁ to P ₂ , first change the clamp level of the clamp circuit CL from VL ₁ to VL ₂ as shown in Figure 1 using variable resistor VR ₂ ,
Thereafter, variable resistor VR ₃ connects operational amplifier OP ₁ .
A two-step adjustment is required in which the offset voltage of the output voltage is adjusted according to the clamp level _VL2 . Moreover, since accuracy is required for both the clamp level and the offset voltage, there is a problem in that the adjustment work is troublesome.

In particular, with the diversification of functions such as radio-controlled equipment, the operation of which is becoming more complex, the two-step adjustment process described above is a major problem in terms of simplifying operation. It was becoming.

On the other hand, in order to perform the above-mentioned two-step adjustment work in one operation, it is possible to link variable resistors VR ₂ and VR ₃ , but due to variations in the resistance values of the variable resistors, etc. This interlocking operation cannot be used in fields that require precise adjustment operations.

The present invention was developed in view of the above-mentioned circumstances, and uses a single variable resistor to adjust the output rise point and its reference level, thereby simplifying the operability and making the adjustment work more accurate. It is an object of the present invention to provide a variable resistance circuit which is designed to achieve the following.

Hereinafter, one embodiment of the variable resistance circuit according to the present invention will be described with reference to the drawings.

FIG. 3 is a circuit configuration diagram of a main part showing an embodiment of a variable resistance circuit according to the present invention.

Here, in VR ₅ , positive and negative power supplies +V and -V are supplied between the fixed terminals, and the movable element P is connected to a stem mechanism (not shown), for example, as shown in Fig. 4 according to the amount of displacement of the movable element. This is a variable resistor that exhibits output characteristics as shown by the broken line _b1 .

OP ₃ is an inverting amplifier circuit with R ₆ as an input resistor and R ₇ as a feedback resistor, and OP ₄ as an inverting amplifier.
has a diode _D1 with the polarity shown in the figure connected to its output terminal, a feedback circuit is formed between the anode of this diode _D1 and the inverting input terminal (-), and a variable resistor is connected as a clamp level setting section.
This is an operational amplifier that forms a clamp circuit whose clamp level is adjusted by _VR6 .

That is, if the output of the operational amplifier OP ₃ connected via the resistor R ₈ is smaller than the clamp level set by the variable resistor VR ₆ , the diode D ₁ is reverse biased and the output of the operational amplifier OP 3 connected via the resistor R ₈ is The impedance when looking at the operational amplifier OP ₄ side from the side becomes extremely large, and the resistor R ₈ side and the operational amplifier OP ₄ are in a disconnected state.

On the other hand, when the output of the operational amplifier OP ₃ applied via the resistor R ₈ exceeds the clamp level, the diode D ₁ becomes forward biased, causing negative feedback to the operational amplifier OP ₄ , resulting in a so-called voltage follower operation. is performed, the connection point between the resistor _R8 and the diode _D1 is fixed at the clamp level set by the variable resistor _VR6 , and a clamping operation is performed.

OP ₅ is an operational amplifier that adds the inputs provided through resistors R ₉ and R ₁₀ , and R ₁₁
is a resistor inserted in the negative feedback circuit of the operational amplifier _OP5 .

Next, the operation of the circuit configuration described above will be described.

First, the output of the variable resistor VR ₅ is introduced into the operational amplifier OP 3 via the resistor R ₆ , and the output of the variable resistor VR 5 is introduced into the operational amplifier OP ₃ through the resistor R ₆ .
It is inverted and amplified with an amplification degree determined by the ratio of R ₇ (R ₇ /R ₆ ).

Therefore, if the variable resistor VR ₅ has the output characteristic shown by the broken line b ₁ in FIG. 4, the output of the operational amplifier OP ₃ will be as shown by the broken line b ₂ in FIG. The output is inverted.

The output of the operational amplifier _OP3 becomes the anode voltage of the diode _D1 via the resistor _R8 .

Here, if the clamp level set by the variable resistor VR ₆ is set to VL ₃ as shown by the broken line in FIG. 4, the variable resistor VR inverted by the operational amplifier OP ₃ In a region where the output of ₅ is smaller than _the clamp level _VL3 , that is, in a region where the displacement of the mover P is smaller than _P1 shown in FIG.
It becomes disconnected from the resistor _R8 side.

Therefore, the output of the operational amplifier _OP3 is input to the operational amplifier _OP5 using the resistors _R8 and _R10 as input resistances.

On the other hand, the output of the variable resistor VR ₅ is input to the operational amplifier OP ₅ via the resistor R ₉ without having its polarity inverted at the same time.

That is, a variable resistor is connected to the operational amplifier _OP5 .
The output of VR ₅ and its inverted output will be added.

Now, the output of the variable resistor VR ₅ is set to V ₁
(V ₁ < VL ₃ ), and if the output of operational amplifier OP ₅ is V ₀ , then V ₀ = −{R ₁₁ /R ₉・V ₀ +(−R ₇ /R ₆・V ₀ )・R ₁₁ / _R8
+ _R10 }=-( _R11 / _R9 - _R7 / _R6・_R11 / _R8 + _R10 ) _V0 .

Therefore, if the resistors R ₆ to _{R 11} in the above equation are selected in advance so that R ₁₁ /R ₉ = R ₇ /R ₆ · R ₁₁ /R ₈ + R ₁₀ , the inverted variable The output of resistor VR ₅ is at clamp level
In the region below VL ₃ , the output of operational amplifier OP ₅ is fixed to zero.

On the other hand, if the output of the inverted variable resistor VR ₅ exceeds the clamp level VL ₃ , the diode
D ₁ is forward biased, which causes operational amplifier OP ₄
A negative feedback circuit is formed in , so that operational amplifier _OP4 operates as a voltage follower circuit.

Therefore, the connection point between the diode D ₁ and the resistor R ₈ is fixed at the clamp level VL ₃ , and this clamp level and the output of the variable resistor VR ₅ are inverted and added by the operational amplifier OP ₅ . Solid line in figure 4
As shown by a ₁ , with P ₁ as the rising point, mover P
It becomes possible to obtain an output that changes depending on the amount of displacement.

That is, the amount of displacement of the movable element P of the variable resistor VR ₅ exceeds _P1 , and the variable resistor VR ₅ is inverted.
When the output of the circuit becomes equal to or higher than the clamp level VL ₃ , the circuit consisting of the operational amplifier OP ₄ operates as a clamp circuit, and the clamp level VL ₃ is applied to the operational amplifier OP ₅ as an offset voltage.
This offset voltage adjusts the reference level of the output of the operational amplifier _OP5 to obtain desired output characteristics.

Furthermore, the rising point of the output is set to P ₁ as shown in Figure 4.
If you are trying to change from P to ₂ , use a variable resistor
If the clamp level set by VR ₆ is changed to VL ₄ as shown by the broken line in Figure 4, the output will be fixed to zero in the region where the displacement of mover P is less than P ₂ due to the same effect as described above. In addition, in the region exceeding _P2 , the fourth reference level is adjusted by the clamp level output from the operational amplifier _OP4 .
This makes it possible to obtain an output with the characteristics shown by the solid line _a2 in the figure.

In this way, in the variable resistance circuit according to the present invention,
By adjusting the variable resistor VR ₆ , you can simultaneously adjust the output reference level and set the output rise point, which is expected to greatly improve operability.

Further, since the output level adjustment and the rise point setting are performed based on the output of one variable resistor VR ₆ , accurate adjustment can be performed.

Next, FIG. 5 shows an example in which the variable resistance circuit according to the present invention shown in FIG. 3 is applied to an actual radio-controlled device.

The example shown in FIG. 5 is an example in which the present invention is applied to a radio-controlled transmitter for operating a speedboat.

That is, a boat moves forward by obtaining propulsive force from the rotation of a propeller in the water, but the hull receives a reaction force due to the rotation of this propeller. The magnitude of this reaction force varies depending on the propeller rotation speed. In other words, the magnitude of the reaction force is different at maximum speed and maximum deceleration, so for example, if you adjust the balance of the hull so that it is traveling straight at maximum speed, at maximum deceleration the hull will move to the right or to the right depending on the direction of rotation of the propeller at maximum deceleration. Alternatively, the inconvenience of turning left and proceeding may occur.

Therefore, the configuration shown in FIG. 5, in which parts having the same functions as those in FIG. 3 are denoted by the same reference numerals, is capable of automatically correcting the curvature of the hull.

In the case of an actual radio-controlled transmitter, since it generally uses a single power supply system, one end of the fixed terminal of each variable resistor is grounded, and the other end is connected to the power supply +V.

Therefore, the operating reference level of the operational amplifier is different from the ground potential, and the operating reference level is created by the resistors _R12 and _R13 , and the operational amplifiers _OP3 and _OP5
and giving to OP ₆ .

Also, the clamp circuit consisting of the operational amplifier OP ₄ is configured in the direction of clamping, i.e. when the output of the operational amplifier OP ₃ given via the resistor R ₈ is equal to or higher than the clamp level set by the variable resistor VR ₆ . In addition to the diode D ₁ for operating this clamp circuit, a diode D ₂ of the polarity shown is added to perform the clamp operation when the output of the resistor R ₈ is below the clamp level, and the direction of the clamp is The switch S ₁ is configured to short-circuit one of the diodes D ₁ and D ₂ depending on the situation.

Furthermore, the operational amplifier OP ₅ constituting the adder circuit is provided with a variable resistor VR ₇ for adjusting the degree of vibration in parallel with the resistor R ₁₁ for negative feedback, and furthermore, the above-mentioned calculation operational amplifier OP ₆ for switching the polarity of the output of amplifier OP ₅ , resistor R ₁₄ ,
R ₁₅ and switch S ₂ are provided.

In the above configuration, the output of the variable resistor _VR5 is connected to the encoder section EC via the resistor _R16 .
to form a channel signal for propeller control (speed control).

On the other hand, the output of the operational amplifier OP ₅ whose polarity is switched by the switch S ₂ is mixed with the output of the variable resistor VR ₈ for controlling the steering amount, which is introduced into the encoder section EC via the resistor R ₁₇ . Therefore, when the rotation speed of the propeller, which is determined by the amount of displacement of the movable element P of the variable resistor VR ₅ , becomes equal to or greater than the value corresponding to the clamp level set by the variable resistor VR ₆ , the variable resistor The output of the variable resistor VR ₅ is mixed with the output of the resistor VR ₈ , and the steering amount is automatically corrected.
By adjusting the clamp level with VR ₆ , it is possible to operate the boat in a straight line without changing its speed.

By the way, the configuration shown in FIG. 5 is not limited to a transmitter for a speed boat, but can of course be applied to a transmitter for an airplane or a helicopter.

Furthermore, in each of the embodiments described above, an example was explained in which the clamp circuit was connected to the output side of the variable resistor VR ₅ whose polarity was inverted, but the clamp circuit was connected to the output side of the variable resistor VR ₅ whose polarity was not inverted. , the output of this clamp circuit and the output of operational amplifier _OP3 may be added by operational amplifier _OP5 .

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

As described above, the variable resistance circuit according to the present invention connects and controls a clamp circuit whose clamp level can be arbitrarily set to either the output of the variable resistor or its inverted output, and controls the output of the variable resistor. The configuration is such that the output of and its inverted output are added.

However, in the variable resistor circuit according to the present invention,
In one region centered on the clamp level, the output of the variable resistor and its inverted output are added and canceled, and in the other region,
Since the output of the variable resistor is offset by the clamp level, the operation of adjusting the clamp level results in:
It becomes possible to set the reference level and rise point of the output at the same time, which has an extremely large effect in terms of simplifying the operation or improving the operability.

In addition, in the variable resistance circuit according to the present invention, the reference level is set and the rise point is adjusted based on the output of one variable resistor, so accurate adjustment is always possible. The effects obtained are also extremely large.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the operation of a conventional variable resistance circuit, Fig. 2 is a circuit configuration diagram showing an example of a conventional variable resistance circuit, and Fig. 3 is an example of a variable resistance circuit according to the present invention. FIG. 4 is a circuit diagram showing the embodiment. FIG. 4 is a diagram for explaining the operation of the embodiment. FIG. 5 is a circuit diagram showing an example in which the embodiment is applied to a radio-controlled transmitter. VR ₅ , VR ₆ ... Variable resistor, OP ₃ to _{OP 5} ... Operational amplifier, R ₆ to _{R 11} ... Resistor, D ₁ ... Diode.

Claims (1)

[Scope of utility model registration request] In a variable resistance circuit that obtains an output according to the amount of operation by operating an operating mechanism connected to a movable element of a variable resistor, an inverting circuit that inverts the output of the variable resistor, and an output of this inverting circuit. a clamp circuit that is connected to either the side or the output side of the variable resistor and performs a clamp operation when the connected output reaches the clamp level, and a clamp level setting section for setting the clamp level of this clamp circuit. and an addition circuit that adds the output of the inverting circuit and the output of the variable resistor.