JPS60175125A - Adjusting device of output - Google Patents

Abstract

PURPOSE:To prevent an accident due to excess current by forming a reference voltage setting circuit for previously setting maximum current to be made to flow into a load at the application of a required voltage from a current/voltage generating circuit to a load. CONSTITUTION:A prescribed reference voltage is generated from a voltage setter 2 by turning a dial 1 in an output adjusting device. The voltage is inputted to the current/voltage generating circuit 4 through a voltage control circuit 3 and then applied from an output terminal 6 to parts to be tested or the like through a detecting circuit 5. The detected output from said detecting circuit is compared with said reference voltage by a voltage comparator 7 and the compared result is fed back to said voltage control circuit 3 to hold the output voltage level precisely. At that time, output current is also detected 5 and a reference voltage from a setting circuit for setting the maximum current enabled to be supplied (allowable maximum output current) is compared 9 with the detected output. When said detected output exceeds the reference voltage, current flowing into the load is limited by a current control circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an output regulating device such as a current voltage generator.

Current/voltage generators are designed to accurately generate a desired level of current or voltage by operating a dial, etc., and are widely used for electrical precision testing of various electronic devices and electronic components. .

However, when testing the voltage characteristics of components, for example, increasing the applied voltage generally increases the flowing current, so there is a risk that this current may inadvertently exceed the component rating and damage the component. be. For this reason, in voltage or current generators, the maximum current is usually set for voltage generation, and the maximum voltage is set for current generation, but this was originally intended to protect the voltage or current generator. is the main purpose, and depending on the type of load, this is not a desirable setting method.

This invention was made in view of the above points, and its purpose is to adjust the maximum current to be supplied to the load in advance according to the changing voltage when the output voltage of the current voltage generator is changed. An object of the present invention is to provide an output adjustment device that can be adjusted and set.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows the main parts of an output adjusting device according to the present invention applied to a current/voltage generator or the like. Referring to the figure, a desired range is set using, for example, a range changer (not shown), and then the dial 1 is rotated and scaled so that the output voltage is at a predetermined level. The voltage setting device 2 generates a variable voltage Vg corresponding to a specified level in conjunction with the rotation of the dial 1. This variable voltage Vs serves as a reference voltage for the output voltage, and is converted into a voltage control signal via the voltage control circuit 3 and input to the current and voltage generation circuit 4. This current/voltage generating circuit 4 includes, for example, a current generating unit and a voltage generating unit (not shown), and the voltage control signal is applied to the voltage generating unit. In response to this voltage control signal, a voltage at a level set by the dial 1 is generated from the current/voltage generating circuit 4, passed through the detection circuit 5, and is applied from the output terminal 6 to a component under test (not shown). In this case, the level of the output voltage is generally detected by the detection circuit 5, and the detected output is sent to the voltage comparison circuit 7 and compared with the variable voltage Vs. If a difference occurs between the two voltages, the difference voltage is fed back to the voltage control circuit 3. The voltage control signal controls the voltage generating unit (not shown) so that this differential voltage becomes zero, thereby accurately maintaining the level of the output voltage set by the dial l.

The output adjustment device according to the present invention is configured so that when the output voltage level is detected in the detection circuit 5, the output current level is also detected, and the maximum supplyable current, in other words, the maximum allowable output current is set. The reference voltage provided for this purpose is compared with the detection output of the current actually flowing through the load, and if the detection output exceeds the reference voltage, the current flowing through the load is limited. It is. In the case of this example, the maximum allowable output current for the upper 8M has three patterns: for example, it increases or decreases in proportion to the increase or decrease in the output voltage, it increases or decreases in inverse proportion to the increase or decrease in the output voltage, or it remains constant regardless of the increase or decrease in the output voltage. Allowed to change. Roughly dividing the configuration of this output adjustment device, the above-mentioned current voltage generation circuit 4
In addition to the detection circuit 5, a reference voltage setting circuit 8 is used to configure the quasi-voltage described in Section 2, and a current comparison circuit (hereinafter referred to as a "comparator") that compares the reference voltage formed here with the detection output of the load current. ) 9 and a current control circuit (hereinafter referred to as "control circuit") that controls the level of the output current of the current/voltage generating circuit 4 based on the signal from the comparator 9.
That's what it means. )10 etc.

FIG. 2 shows an example of a specific circuit configuration of the reference voltage setting circuit 8. To further explain with reference to the figure, this basic voltage setting circuit 8 is as follows.

A voltage setting device 2 that generates a variable voltage Vs in conjunction with the operation of the dial 1, a fixed power supply 11 that generates a constant level voltage Vc regardless of the operation of the dial l, and these two voltages Va. An adder 12 for combining Vc to form a reference voltage Vr, and a switch 13 for changing the level of the reference voltage Vr in, for example, three patterns by switching the addition operation of the adder 12. It is equipped with In this output adjustment device, the level change pattern of the reference voltage Vr is a reference pattern, and the level change pattern of the allowable maximum output current Im applied to the load from the current voltage generation circuit 4 is the reference voltage Vr. It is made to be similar to the level change pattern of.

In the reference voltage setting circuit 8 configured in this manner, the adder 12 includes, for example, five analog switches S1 to S5 and five resistors R1 to R5, each of which has one end connected to the input side of each of these analog switches. ,2
It has two amplifiers 14 and 15. Among these resistors, the other end of the resistor R1 is connected to the output side of the voltage setting device 2, and the other ends of the resistors R2 to R4 are connected to the output side of the fixed power supply 11, respectively. The other end of the resistor R5 is connected to the output side of the amplifier 14. This amplifier 14 is, for example, an inverting amplifier with an amplification factor l, which is composed of an operational amplifier and a resistor, and its (-) input terminal is connected to the output side of the voltage setting device 2, and its (+) side is grounded. has been done. The variable voltage Vg of the voltage setting device 2 is applied to the analog switch S1 via the resistor R1, and becomes a variable voltage Vs whose polarity is inverted by the amplifier 14, and this variable voltage '7g is applied via the resistor R5. It is adapted to be applied to the analog switch S5.

The respective output sides of the analog switches S1 to S5 are connected by a common wiring and connected to the input end of the amplifier 15. This amplifier 15 is a buffer amplifier composed of, for example, an operational amplifier and a resistor R15, and the outputs from the analog switches S1 to S5 are combined by this amplifier 15 and sent to the comparator 9. . In this case, each gate signal input side of the analog switches S1 to S5 is connected to a switch 13, and their on/off operations are selectively controlled by operating the switch 13.

In this embodiment, the switch 13 is, for example, A.

A pushbutton switch with three circuits B and C is used,
It is configured so that when any one circuit is turned on, the other two circuits are turned off. The above A circuit of this switch 13 is:
For example, one of the contacts is the analog switch S1 and 8.
Similarly, one contact of the 8 circuit is connected to the gate signal input side of the analog switch S3, and one contact of the C circuit is connected to the gate signal input side of the analog switch S4 and 85. are connected to each. The other contacts of the A, B, and 03 circuits are connected by a common medal line and connected to the DC power supply 16, etc. For example, when the switch of the A circuit is turned on, the voltage of the DC power supply 6 is connected to the analog switch S1. 82, and these two analog switches are turned on.

Next, the operation of this output adjusting device will be explained with reference to FIGS. 3 to 6.

Now, when the pushbutton type switch 13 is pressed to turn on the six circuits, the analog switches S1 and 82 are turned on, and the output side of the analog switch S1 has a dial l, as shown by Vs in FIG. An increasing voltage appears as the rotation is operated.

A constant voltage independent of the rotational operation of the dial 1 appears on the output side of the analog switch S2, as shown by Vc in the figure. These two voltages are combined in an amplifier 15, and a reference voltage Vr as shown in FIG. 4(a), for example, appears on the output side.

In this case, as is well known, the level of the reference voltage Vr is determined by the levels of the variable voltage Vs and the constant voltage Vc, and the values of the resistors R1, R2, R15, etc.

When the switch 13 is pressed to turn on the 8 circuits, the analog switch S3 is turned on, and a constant voltage as shown, for example, by Vc in FIG. 3 appears on its output side. This constant voltage Vc is input to an amplifier 15, and a reference voltage Vr as shown in FIG. 4(b) appears at its output side, for example.

When switch 13 is pressed to turn on cIgIm, analog switches S1 and 85 are turned on, and analog switch S
For example, a voltage as shown by Vc in FIG. 3 appears on the output side of analog switch S5, and as shown by Vg in the figure at the output side of analog switch S5.

As the dial 1 is rotated, a voltage that increases toward the (-) side appears. These two voltages Vc and Vs are combined in the amplifier 15 in the same way as when the input circuit is on, and a reference voltage Vr as shown in FIG. 4(c) appears on the output side thereof. In this embodiment, a case has been described in which the change in the level of the reference voltage Vr has three patterns as described above, but any number of patterns may be provided.

The reference voltage Vr is sent from this reference voltage setting circuit 8 to a comparator 9. On the other hand, when the load current is detected in the detection circuit 5, the detection output is converted into a voltage and input to the comparator 9, where the level is compared with the reference voltage Vr. Now, let us take the case shown in Fig. 4 (a) above as an example and rewrite it as shown in Fig. 5 to make it easier to understand.The horizontal axis in the figure is the output voltage generated as the dial 1 is rotated. Therefore, it can be thought of as replacing the dial scale with a voltage scale.

The vertical axis represents the voltage levels compared within the comparator 9. As shown in the figure, when the output voltage applied to the load increases by rotating the dial 1, the reference voltage Vr also increases accordingly. The control circuit 10 converts the reference voltage Vr input from the reference voltage generation circuit 8 into a current control signal and applies it to a current generation unit (not shown) of the current and voltage generation circuit 4. In the current generation unit, the current amplification factor and the like are controlled by this current control signal, and the maximum value of the output current, that is, the allowable maximum output current Im, is set to the fourth value as shown in FIG. It is designed to be changed in a pattern similar to that shown in Figure (A).

Now, for example, a fifth signal is sent from the detection circuit 5 to the comparator 9.
Assuming that a load current detection output as shown by the dotted line (1) in the figure is input, this detection output is at a lower level than the reference voltage Vr corresponding to the maximum value of the output current, so the comparator 9 No signal is sent from the. The load current is less than the allowable maximum output current Im shown in FIG. 6(a), and the current and voltage generating circuit 4 has a margin, so the load current is allowed to flow as is.

By rotating the dial 1, the output voltage increases and the load current also increases, and the detected output reaches the same level as the reference voltage Vr at the time of the output voltage Vo, as shown by the dotted line (2) in FIG. It is assumed that it has been reached. If the detected output exceeds the reference voltage Vr when the output voltage is further increased, a signal corresponding to the exceeded voltage difference is sent from the comparator 9 to the control circuit 10. In the control circuit IO, the current control signal sent to the current/voltage generating circuit 4 is modulated by the signal input from the comparator 9, as in the case of the voltage control circuit 3 described above. In the current/voltage generating circuit 4, the current amplification factor, etc., for example, is controlled by this modulated current control signal in a direction that makes the differential voltage zero. As a result, the same figure (2
) The detected output of the load current bends along the change pattern of the reference voltage Vr at the point of the output voltage Vo set by the dial 1, and the output voltage is also suppressed at the same time.

Therefore, a current larger than the allowable maximum output current rm shown in FIG. 6(a) will not be applied to the load.

The reference voltage V as shown in (b) or (c) of Fig. 4
The same applies when the detection output of the load current becomes larger with respect to r, and the load current at a level higher than the allowable maximum output current Im shown in Fig. 6 (b) or (c) will not be applied. Since it is obvious, its explanation will be omitted.

As described above in detail, the output adjustment device according to the present invention is capable of supplying the desired voltage to the load when a desired voltage is applied to the load from the current/voltage generating circuit 4 by rotating the dial 2 or the like. A reference voltage setting circuit 8 is provided that allows the maximum current In to be set in advance.

This reference voltage setting circuit 8 is a voltage setting device that generates a variable voltage Vs as a reference for various levels of voltage outputted from the current/voltage generating circuit 4 in conjunction with the rotation operation of the dial l. 2, a fixed type 3111 that generates a voltage Vc at a constant level regardless of the rotational operation of the dial l, and a reference voltage Vr whose level changes in three patterns by combining these voltages. It has an adder 12 and the like. The change pattern of this reference voltage Vr is arbitrarily switched by the switch 13 in consideration of the load to be connected, and the output thereof is converted into a current control signal via the control circuit 10, and then the current/voltage generating circuit 4 In the electromotive current voltage generation circuit 4, which is designed to be applied to the current, the maximum current of 1 m to be applied to the load is set by this current control signal, and
When the load current exceeds the maximum current Im, its detection output is fed back via the control circuit 10, thereby suppressing an abnormal increase in current. Thereby, the load current is caused to flow along the set change pattern of maximum ionization Im.

Therefore, when the output adjustment device according to the present invention is applied to testing various electronic devices and components, the method of supplying current can be selected in accordance with the form of the load. For example, in the case shown in Figure 6 (A), the maximum allowable output current is also increased as the output voltage increases, so it is useful for testing the maximum allowable power of resistors, etc., and in the case shown in Figure 6 (B). is a substitute for a power supply with a constant output current protection circuit.

In the case of (c) in the same figure, since the electric power output is approximately constant, it is used for testing various parts, etc., and it is possible to avoid accidents such as inadvertently flowing excessive current exceeding the rating and damaging parts during testing. In addition to being useful for preventing excessive currents, it is also effective for protecting signal sources such as current and voltage generating circuits from excessive currents.

Note that, although the above explanation has been made regarding the case of setting the allowable maximum output current in response to an increase or decrease in the output voltage, the present invention can be similarly applied to the case in which the allowable maximum output voltage is set when the output current is increased or decreased. is clear.

[Brief explanation of the drawing]

The attached drawings relate to embodiments of the present invention. FIG. 1 is a block diagram showing the main parts of the overall ellipse, FIG. 2 is a diagram showing the specific configuration of the reference voltage setting circuit, and FIGS. 3 and 4 are diagrams explaining the operation of the reference voltage setting circuit, FIG. 5 is an explanatory diagram of the operation of the comparator, and FIG. 6 is an explanatory diagram of the operation of four output adjustment devices according to the present invention. In the figure, 2 is a voltage setting device, 4 is a current/voltage generation circuit, 5 is a detection circuit, 8 is a reference voltage setting circuit, 9 is a comparator, and I
0 is a control circuit, 11 is a fixed power supply, 12 is an adder, 13 is a switch, and 15 is an adder amplifier. Patent applicant day 1i! X Denki Co., Ltd. Agent Patent Attorney Taku Ohara Figure 1 2 11 13 Figure 3

Claims (1)

[Claims] A reference voltage setting circuit for setting a voltage signal corresponding to the maximum current (or maximum voltage) that can be supplied to a load from a current voltage generator, and the above voltage sent from the reference voltage setting circuit. a control circuit that receives a signal and sends a control signal to enable the current/voltage generator to output the maximum current (or maximum voltage); and a detection circuit that detects the load current (or load voltage) and detects the load current (or load voltage). a comparator for comparing the detection output and the voltage signal, and feedback for reducing the load current (or load voltage) from the control circuit to the current and voltage generator when the detection output exceeds the level of the voltage signal; An output adjustment device configured to generate a signal, wherein the reference voltage setting circuit generates a first signal that generates a variable voltage signal in response to an increase or decrease in the output voltage (or output current) of the current/voltage generation amount. a second signal source that emits a constant voltage signal; and a plurality of semiconductor switching elements each receiving the variable voltage signal and the constant voltage signal from the first and second signal sources. and a summing amplifier that synthesizes signals output when the semiconductor switching elements are sequentially switched on and off in a plurality of combinations via a switch to form a plurality of patterns of signals, the summing amplifier An output adjustment device characterized in that it sends out a signal formed by the above as a reference voltage signal corresponding to the maximum current (or maximum voltage) supplied to the load.