JP2934055B2 - Resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistor having almost no heat generation.

[0002]

2. Description of the Related Art Conventional resistors involve power consumption. That is, when the current flowing through the resistor R is I and the voltage applied to the resistor R is V, the power consumption P is P = R · I ²
= VI (wat). Here, 1 watt = 1
J / S.

[0003]

However, the resistance R
When a current I flows through the inside for t (s), heat H = R · I ² t
(J) occurs. Here, the unit of H is J (joule).
It is. Therefore, when P = 1 [W] and substituted into H,
1 (Wh) = 3600 (J) of heat will be generated.

[0004] As described above, the conventional resistor generates heat due to power consumption, and the temperature always rises. Therefore, how to dissipate and diffuse the heat generated from this resistor has been a major problem. Also, the power consumption is large, which is also a major problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and has the following structure as one means for solving the above-mentioned problems. That is, a pulse signal output means for outputting a pulse signal having a predetermined effective power amount corresponding to the equivalent resistance value, and a first external signal connected to the high potential side of the connection circuit for outputting the pulse signal from the pulse signal output means. Pulse conversion means for converting the supply voltage from the connection terminal to a pulse signal having an amplitude of a third external connection terminal voltage connected to the ground potential side of the connection circuit; and rectifying and smoothing the converted pulse signal of the pulse conversion means. And output means for outputting an output to a second external connection terminal connected to the load, and detection means for detecting a change in current caused by a change in the connection load. The output signal is fed back, and the pulse signal output means modulates the output pulse width so that the current value detected by the detection means is constant.

For example, when the present resistor is used as a pull-up resistor, a load is connected between the first external connection terminal and the second external connection terminal, and when the present resistor is used as a pull-down resistor, the second external connection terminal is used. A load is connected between the connection terminal and the third connection terminal.

[0007]

With the above arrangement, it is possible to provide a resistor that generates little heat and consumes little power despite operating as a resistor.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the drawings.

[0009]

FIG. 1 is a diagram showing the configuration of an embodiment according to the present invention. Hereinafter, the schematic configuration of the first embodiment according to the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes an oscillation circuit for generating a pulse signal of a predetermined frequency, and 2 denotes an oscillation circuit.
A pulse width modulation circuit for performing pulse width modulation with an arbitrary pulse width on the pulse signal is a PNP transistor, 4 is an NPN transistor, both transistors are totem pole connected, and a collector of the PNP transistor 3 The terminal is connected to the external connection terminal A, the emitter terminal of the NPN transistor 4 is connected to the external connection terminal C,
The emitter terminal of the NP transistor 3 is connected to the collector terminal of the NPN transistor 4. Further, the base terminals of the transistors 3 and 4 are connected to the output of the pulse width modulation circuit 2.

Reference numeral 5 denotes a filter circuit disposed between the collector terminal of the PNP transistor 3, the emitter terminal of the NPN transistor 4, and the external connection terminal B.
And C, and smoothes a pulse signal to be described later from the collector terminal of the PNP transistor 3 and the emitter terminal of the NPN transistor 4. Reference numeral 6 denotes a pulse condition setting circuit which receives the output of the filter circuit 5 (external connection terminal B) and controls the modulation pulse width of the pulse width modulation circuit 2 according to the input value. That is, feedback is performed to correct the load fluctuation.

Reference numerals 21 to 23 denote bead filters for reducing the effects of noise or electromagnetic waves due to pulses on the connection circuit. These bead filters 21 to 23 are provided.
Alternatively, the entire circuit of this embodiment may be shielded by an electromagnetic shielding member. Alternatively, a configuration including both of them may be adopted. As the electromagnetic shielding member, for example, a ferrite material or the like can be used.

The principle of operation of the circuit of this embodiment shown in FIG. 1 will be described below. The resistor of the present embodiment is a resistor based on a concept completely different from the conventional concept of a resistor, and is an equivalent resistor having an apparently equivalent function to the conventional resistor. ing. Then, the resistor of this embodiment is driven in a pulsed manner to obtain a desired resistance value equivalently.

The output pulse signal a from the oscillation circuit 1 outputs a pulse signal having a duty ratio of 1: 1 at a predetermined frequency indicated by a in FIG. This pulse signal is converted to a pulse width modulation circuit 2
Then, pulse width modulation is performed on a signal having a pulse width corresponding to the resistance value of the present embodiment. For example, the pulse signal is modulated as a pulse indicated by A in FIG. 3 or a pulse indicated by B in FIG.
This signal b is output from the totem-pole connected transistors 3 and 4
, And is converted into a pulse signal indicated by A 'or B' in FIG. 3 and input to the filter circuit 5. In the filter circuit 5, this input signal is smoothed, and "I _1- (I ₁ bar)" indicated by hatching is added to the signal indicated by A 'or B' in FIG.
Alternatively, it is converted to a DC current of “I ₂ − (I ₂ bar)” and output to the external connection terminal B. The above is the basic circuit operation of the circuit of this embodiment.

As a mode used as a resistor in an actual circuit, there are a pull-up type and a pull-down type shown in FIG. In FIG. 4, Ru is a pull-up resistor,
Rd is a pull-down resistor. The circuit form of the equivalent resistance differs depending on which one is used. Hereinafter, the case where the resistor of the present embodiment is used as a pull-up resistor will be described first.

When used as a pull-up resistor, a portion between the external connection terminal A and the external connection terminal B of the resistor shown in FIG. 1 is used as a load resistance, and the external connection terminal C is grounded. That is, the connection state shown in FIG. 5 is used. In this case, Va, which is approximately the circuit power supply voltage, is applied to the external connection terminal A, and the high-level potential of the output signal from the oscillation circuit 1 and the pulse width modulation circuit 2 is approximately this voltage Va.

The oscillation circuit 1 outputs a pulse signal having a high potential level of approximately Va and a cycle t ₁ shown in FIG. 3A. Note that the duty ratio of the pulse signal is 50% or any other duty ratio. In response to the pulse signal, the pulse width modulation circuit 2 generates a pulse width-modulated signal having a pulse width of which the resistor has a desired equivalent resistance value by means of a built-in volume, and generates a modulation signal of both transistors 3 and 4. Output to the base terminal. This pulse width can be adjusted to an arbitrary pulse width at t ₀ as shown by A or B in FIG.

Transistors 3 and 4 of totem pole configuration
When this modulation signal is input to the base terminal of this
When the signal is low level, the PNP transistor 3 is turned off.
The NPN transistor 4 is turned on and the pulse is high.
Level, the PNP transistor 3 is turned on and the NPN
The transistor 4 is turned off. As a result, the signal line c
High level is I₁And the low level is the ground level, the base
Modulation signal A or B having substantially the same phase as the terminal input pulse signal
Are output at substantially the same timing as. This pulse width variation
The tuned signals are shown at A 'and B'. This signal is
A ′ that is rectified / smoothed by the
And B 'at the diagonal level.₁− (I ₁Bar)
Or "I_Two− (I_TwoBar) ”DC current signal (open
DC voltage) is output.

Hereinafter, the principle of the resistor of this embodiment will be described.
This embodiment resistor, say switch circuit is equivalently driven by a pulse signal from the pulse width modulation circuit 2, in principle, as shown in FIG. 6, the DC voltage of the power supply V _o is the switching circuit it is configured to have One Kuwawa in a pulsed manner to the load resistor R _o by the operation. In the case of Figure 6, the peak voltage of the pulse is V _o, which is applied to a pulsed manner to the load resistor, so that the pulse current flows as a result. The average current "I- (I bar)" based on the pulse current at this time can be expressed as follows.

[0019]

(Equation 1)

As a result, the switch is replaced with the equivalent resistance Ref.
Assuming that f, this Ref can be expressed as follows. _{Reff = R O (t s /} t o) (1) also can be expressed also equivalently in cowpea to the circuit of FIG.

The effective resistance of this _{circuit, Reff = {(t s +} t 0) / C} · {1 / (1-e -t0 / RoC)} - given by _{R o (2), {t} 0 / If (R _o C) ≪1, then Reff = R _o (t _s / t _o ) (3).

That is, the above expressions (1) and (2) have the same conclusion. Thus, the equivalent resistance seen to be proportional to _{R o (t s / t 0} ). This is the basic operation principle of the resistor of this embodiment. However, this remains a will depend is Reff the load resistance R _o, difficult to use. Therefore, in this embodiment, it is desirable to adopt the following method.

That is, a method of controlling the supply current to the load resistance R _O to be constant, a method of controlling the voltage to be constant, and the like can be considered. These basic circuits are the circuits shown in FIG. 8, which detect the state of the load resistance R _O in the form of current or voltage, and based on the detection result, the pulse condition setting circuit 6 generates the oscillation circuit 1 and the pulse width modulation circuit. The pulse width is automatically adjusted by controlling the pulse width generated by the pulse generator composed of the two, so that the supply current to the load resistor R _O is constant or the voltage is constant. Control. The filter is for making the pulse waveform smooth.

To keep the current constant, the load resistance R _o
The pulse width T _s so that Reff also fluctuates with respect to the fluctuation of
(Control the voltage value applied to the load resistance _Ro so that the current is constant). For example, a reference current value is compared with a current value flowing through the load resistor _Ro , and control is performed to eliminate the difference. Incidentally, in this case, the maximum voltage that can be applied to the load resistor R _o is up to V _o, is limited to the resistance value of the load resistor.

For example, when R _O = 10Ω, and when a constant current I = 0.5 A is desired to flow, V _o = 10 V
The following describes an example where t ₀ = 1 ms. FIG.
The resistance value R as a whole in the circuit of FIG.
_Expressed as RO. I = 0.5 A means that V _o = 10
In the case of V, it is necessary that R = 20Ω. R = Reff
From + R _O = 20Ω, Reff = 10Ω.

[0026] The above-mentioned formula formula _{Reff = R O (t s /} t
_o ) indicates that t ₀ = 1 ms to t _s = 1 ms. Therefore, from the pulse generator, t ₀ = 1 m
What is necessary is just to control so that a pulse of s, t _s = 1 ms is generated. During this state, the resistance value of R _o varies, R _O =
When the resistance drops sharply to 1Ω, R = Reff + R _O = 20
Reff = 19Ω from Ω. Therefore, it is sufficient to control so that a pulse of t _s = 11 ms is generated from the above formula.

FIG. 9 shows the relationship between the resistance value of R _O and the pulse width of t _s when a constant current of I = 0.5 A is desired.
FIG. 10 shows the relationship between the feedback voltage to the pulse generator and the pulse width t ₀ by the pulse condition setting circuit 6. In the circuit of FIG. 8, when R _o = 10Ω, V _o = 10
8, the potential at point d in FIG. 8 becomes 5 V, and 5 V is sent to the pulse condition setting circuit 6. The pulse condition setting circuit 6 controls so that a pulse of t _s = 1 ms is output from the pulse generator as shown in FIG. 10 when 5 V is input.

If R _o = 1Ω, Reff = 19
8, the potential at the point d in FIG. 8 becomes 0.5 V, and 0.5 V is sent to the pulse condition setting circuit 6. As shown in FIG. 9, the pulse condition setting circuit 6 receives t _s =
Control is performed so that a pulse of 19 ms is output. In addition,
When V _o = 10 V, if the resistance value R is 20 Ω or more, the current cannot be controlled to a constant current, and the resistance value of the load resistance is limited.

Furthermore, in order to make the voltage constant by controlling the pulse width T _0, control such that the voltage applied to the load resistor R _o for variations in the load resistance R _o of Reff becomes constant do it. For example, a reference voltage value is compared with a voltage value at a point d which is a voltage applied to the load resistor _Ro , and control is performed so as to eliminate the difference. In this case, the minimum load resistance _Ro is limited.

The circuit shown in FIG. 1 realizes the above principle with an actual circuit. Even when the circuit shown in FIG. 1 is used as a pull-up resistor as shown in FIG. 5, heat generation of Ru does not occur in principle, and the saturation voltage (about 0.2 V to 0.4 V) of the transistor is slightly increased. Saturation resistance (several ohms to tens of ohms)
And only slight heat from each circuit. However, these heat generations are very small, and a resistor having almost no heat generation can be obtained. Furthermore, since it is not a method of consuming a large current and converting it to heat, the power consumption of the resistor can be suppressed low.

In the above, an example in which the resistor of this embodiment is used as a pull-up resistor has been described. However, this embodiment can also be used as a pull-down resistor. In this case, as shown in FIG. 11, the external connection terminal A is connected to the power supply, the external connection terminal B is connected to the load resistor Ro, and the external connection terminal C is connected to the ground side. Also in this case, the equivalent resistance Rd is uniquely determined according to the set value of the volume of the pulse width modulation circuit 2 in the same manner as in the case where the equivalent resistance Rd is used as the pull-up resistor, and there is no difference. Also in this case, there is almost no heat generation from the resistor.

As described above, according to this embodiment, the power consumption and the heat generation of the resistor can be suppressed low.

[0033]

Second Embodiment The above description has been made with respect to an example in which the principle of the present invention is faithfully implemented as a circuit. However, the present invention is not limited to the above example, and any configuration can be adopted as long as a similar equivalent circuit is achieved. Although the configuration is basically the same as that of the first embodiment described above, a more simplified detailed circuit configuration will be described below with reference to FIG.

FIG. 12 is a detailed circuit diagram of a second embodiment according to the present invention.
And a duty ratio variable type oscillation circuit including the pulse width modulation circuit 2 and the duty ratio can be arbitrarily changed by the volume VR1. And
TR1, TR2, R1 to R4, C1, and C2 constitute a CR oscillation circuit. An output pulse signal from the CR oscillation circuit 30 is supplied to a PNP transistor TR via a resistor R5.
3 and turns on / off the transistor TR3.
Turns off and outputs an inverted signal of the input signal. The collector of the transistor TR3 is connected to the base of an NPN transistor TR4 pulled up by a resistor R7 via a resistor R6. The collector of the transistor TR3 is inverted by the transistor TR4. A pulse signal having a high supply voltage from the external connection terminal A synchronized with the output pulse signal is supplied. This pulse signal is applied to L1 and C3 of the filter circuit 35.
Is rectified and smoothed.

Further, the output current or voltage is field-backed to the CR oscillation circuit 30 via the pulse condition setting circuit 6, and the pulse width of the output pulse from the CR oscillation circuit 30 is modulated. As a result, in the configuration of FIG.
As in the first embodiment shown in FIG. 1, when a resistor having the configuration shown in FIG. 12 is used as a pull-up resistor, the load between the external connection terminal A and the external connection terminal B is set as a load resistance, and the external connection terminal C is grounded. . That is, the connection state shown in FIG. 5 is used. When used as a pull-down resistor, a load resistor is connected between the external connection terminal B and the external connection terminal C, the external connection terminal A is connected to a power supply, and the connection state shown in FIG. 11 is used.

The second embodiment described above can also provide a resistor that consumes less power and generates less heat.

[0037]

Other Embodiments In the above description, an example was described in which the oscillation frequency of the oscillation pulse signal from the oscillation circuit was fixed, and the duty ratio of the oscillation pulse was changed to change the equivalent resistance value.
However, the present invention is not limited to the above examples,
Instead of the pulse width modulation, an FM modulation circuit may be provided so that the oscillation frequency is changed according to the equivalent resistance value to change the open output voltage value at the connection terminal B to obtain a desired equivalent resistance value.

When it is not necessary to make the equivalent resistance variable, the resistance may be divided by a fixed resistance instead of a volume. With this configuration, the adjustment process is not required, and the cost can be reduced.

[0039]

As described above, according to the present invention, it is possible to provide a resistor that generates little heat and consumes less power despite operating as a resistor.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment according to the present invention.

FIG. 2 is a diagram showing an equivalent circuit of the filter circuit of FIG.

FIG. 3 is a diagram showing signal waveforms of respective units of the first embodiment.

FIG. 4 is a diagram showing a mode used as a resistor in an actual circuit.

FIG. 5 is a diagram showing a connection example when the resistor of the first embodiment is used as a pull-up resistor.

FIG. 6 is a diagram for explaining the basic principle of the resistor according to the present embodiment.

FIG. 7 is a diagram showing another example of a circuit equivalently representing the resistor of the present embodiment.

FIG. 8 is a diagram schematically showing a configuration in which pulse conditions are changed by feedback in the resistor of the present embodiment.

FIG. 9 is a diagram illustrating a relationship between a resistance value of a load resistor and a control pulse width in the present embodiment when a constant current is supplied to the load resistor of the first embodiment.

FIG. 10 is a diagram showing a relationship between a resistance value of a load resistor, a feedback voltage and a control pulse width when a constant current is supplied to the load resistor of the first embodiment.

FIG. 11 is a diagram showing a connection example when the resistor according to the first embodiment is used as a pull-down resistor;

FIG. 12 is a circuit diagram of a second embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oscillation circuit 2 Pulse width modulation circuit 5, 35 Filter circuit 6 Pulse condition setting circuit 30 CR oscillation circuit

Claims (2)

(57) [Claims] 1. A pulse signal output means for outputting a pulse signal having a predetermined effective power amount corresponding to an equivalent resistance value, and a pulse signal output from the pulse signal output means connected to a high potential side of a connection circuit. Pulse converting means for converting a voltage supplied from the first external connection terminal into a pulse signal having an amplitude of a third external connection terminal voltage connected to the ground potential side of the connection circuit; and a converted pulse signal of the pulse conversion means Output means for rectifying and smoothing the output and outputting the output to a second external connection terminal connected to the load; and detection means for detecting a current change caused by the fluctuation of the connection load. A value is fed back to the pulse signal output means, and the pulse signal output means modulates an output pulse width so that a current value detected by the detection means is constant. . 2. A resistor according to claim 1, wherein a load is connected between the first external connection terminal and the second external connection terminal in a use mode as a pull-up resistor, and in a use mode as a pull-down resistor. A resistor, wherein a load is connected between the second external connection terminal and the third connection terminal.