JPH0447846B2 - - Google Patents

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 capable of accurately generating a desired level of current or voltage by operating a dial or the like, and are widely used as power supplies for testing 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, the invention may not be 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 switch (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 Vs 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 ensuring that the level of the output voltage set by the dial 1 is maintained accurately.

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 embodiment, the above-mentioned maximum allowable output current changes in three ways: 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. It is made possible. Roughly dividing the configuration of this output adjustment device, in addition to the current/voltage generation circuit 4 and the detection circuit 5, there is also a reference voltage setting circuit 8 for forming the reference voltage, and a reference voltage setting circuit 8 for forming the reference voltage formed here and the load current. A current comparison circuit (hereinafter referred to as
It's called a "comparator." ) 9, and a current control circuit (hereinafter referred to as "control circuit") 10 that controls the level of the output current of the current/voltage generating circuit 4 based on the signal from the comparator 9.

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 reference voltage setting circuit 8
is a variable voltage that is linked to the operation of dial 1 above.
A voltage setting device 2 that generates Vs, a fixed power supply 11 that generates a constant level of voltage Vc regardless of the operation of the dial 1, and these two voltages Vs
an adder 12 for forming a reference voltage Vr by combining It is equipped with In this output adjustment device, the level change pattern of the reference voltage Vr serves as a reference pattern, and the allowable maximum output current applied from the current and voltage generating circuit 4 to the load.
The level change pattern of Im is made to be similar to the level change pattern of the reference voltage Vr.

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, one end of which is connected to each input side of these analog switches. , has two amplifiers 14 and 15. Among these resistances, the resistance R
The other end of the resistor 1 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. Further, 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 of 1, which is composed of an operational amplifier and a resistor, and its (-) side 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 Vs of this voltage setting device 2 is determined by the resistor R1.
The voltage is applied to the analog switch S1 via the amplifier 14, and the polarity of the variable voltage is inverted by the amplifier 14, and this variable voltage is applied to the analog switch S5 via the resistor R5.

The respective output sides of the analog switches S1 to S5 are connected by common wiring and connected to the input side 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. ing. In this case, each gate signal input side of the analog switches S1 to S5 is connected to a switch 13, and its on/off operation is controlled by the switch 1.
It is designed to be selectively controlled by the operation No. 3.

In this embodiment, the switch 13 is, for example, a push button switch having three circuits A, B, and C, and is configured so that when any one circuit is turned on, the other two circuits are turned off. There is. For example, one contact of the A circuit of this switch 13 is connected to the gate signal input side of the analog switches S1 and S2, and similarly, one contact of the B circuit is connected to the gate signal input side of the analog switch S3. ,
Further, one contact point of the C circuit is connected to the gate signal input sides of the analog switches S4 and S5, respectively. The other contacts of the A, B, and C3 circuits are connected by common wiring and connected to the DC power supply 16, etc., and when the switch of the A circuit is turned on, the voltage of the DC power supply 16 is applied to the analog switch S1.
is added to the gate signal input side of S2, and these two
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 push button type switch 13 is pressed to turn on the A circuit, the analog switches S1 and S2 are turned on, and the output side of the analog switch S1 has a dial 1 as shown by Vs in Fig. 3.
An increasing voltage appears as the rotation of the motor increases. The output side of analog switch S2 is connected to Vc in the same figure.
As shown, a constant voltage appears that is unrelated to the rotational operation of the dial 1. Both these voltages are connected to amplifier 1
5, and the output side has, for example, the fourth
A reference voltage Vr as shown in A in the figure appears.
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 B circuit, 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. 4B appears at its output side, for example.

When the switch 13 is pressed to turn on the C circuit, the analog switches S1 and S5 are turned on, and a voltage such as that shown by Vc in Fig. 3 appears on the output side of the analog switch S4, and the voltage on the output side of the analog switch S5 As shown in the same figure,
As the dial 1 rotates, a voltage that increases toward the (-) side appears. These two voltages Vc are combined in the amplifier 15 in the same way as when the A circuit is on, and a reference voltage Vr as shown in FIG. 4C appears on the output side. 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, taking the case of Figure 4 A above as an example,
To make it easier to understand, this can be rewritten as shown in Figure 5. The horizontal axis in the figure is the output voltage generated as the dial 1 is rotated, and if you consider that the dial scale is replaced with a voltage scale, good. 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 converts the reference voltage Vr inputted from the reference voltage generation circuit 8 into a current control signal.
Add to the current generating unit (not shown). In the current generating 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 determined as shown in FIG. 4 above, for example, as shown in FIG. It is designed so that it can be changed in a pattern similar to A.

Now, suppose that the detection output of the load current as shown by the dotted line 1 in FIG.
Since the level is lower than Vr, no signal is sent out from the comparator 9. The load current is less than the allowable maximum output current Im shown in FIG.

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 when the output voltage Vo is reached, as shown by the dotted line 2 in Figure 5, for example. It is assumed that it has been reached. If the detected output exceeds this 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. Control circuit 1
0, the current control signal sent to the current/voltage generating circuit 4 is modulated by the signal input from the comparator 9, almost in the same way 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 the modulated current control signal in a direction to make the differential voltage zero. As a result, the load current detection output shown in FIG. 2 bends along the change pattern of the reference voltage Vr at the set output voltage Vo on the dial 1, and the output voltage is also suppressed at the same time.
Therefore, a current larger than the allowable maximum output current Im shown in FIG. 6A will not be applied to the load.

Reference voltage as shown in Figure 4 B or C
The same applies to the case where the load current detection output becomes larger than Vr, and it is clear that the load current at a level higher than the allowable maximum output current Im shown in Figure 6 (b) or (c) will not be applied. 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 Im 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 rotational operation of the dial 1. 2, and a constant level of voltage regardless of the rotation operation of dial 1 above.
It has a fixed power supply 11 that generates Vc, and an adder 12 that combines these voltages to form a reference voltage Vr whose level changes in three patterns. 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 It is now being added to In the current/voltage generating circuit 4, the maximum current Im flowing through the load is set by this current control signal, and when the load current exceeds this maximum current Im, the detection output is sent to the control circuit 4. 10, and abnormal current increase is suppressed. As a result, 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, it is possible to select the method of supplying current according to the type of the load. For example, in the case shown in Figure 6 A, the maximum allowable output current is increased as the output voltage increases, so it is used for testing the maximum allowable power of resistors, etc., and in the case shown in Figure 6 B, the maximum allowable output current is increased as the output voltage increases. As a substitute for a power supply device equipped with a protection circuit, the case shown in Figure C is used for testing various parts because it provides a nearly constant power output, and is used to prevent excessive current exceeding the rating from being inadvertently applied during testing. In addition to helping to prevent accidents that could damage components, it is also effective in protecting signal sources such as current and voltage generation 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]

All of the attached drawings relate to embodiments of this invention.
Figure 1 is a block diagram showing the main parts of the overall configuration, Figure 2 is a diagram showing the specific configuration of the reference voltage setting circuit,
3 and 4 are diagrams for explaining the operation of the reference voltage setting circuit, FIG. 5 is a diagram for explaining the operation of the comparator,
FIG. 6 is an explanatory diagram of the operation of the entire output adjustment device 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, 10 is a control circuit, 11 is a fixed power supply, 12 is an adder, and 13 is a switch 15 is a summing amplifier.

Claims (1)

[Claims] 1. A reference voltage setting circuit 8 for setting a voltage signal Vr corresponding to the maximum current (or maximum voltage) that can be supplied to the load from the current voltage generator 4, and a reference voltage setting circuit 8 from the reference voltage setting circuit 8. Through the control circuits 3 and 10 that receive the voltage signal Vr sent out and send out a control signal for enabling the current voltage generator 4 to output the maximum current (or maximum voltage), and the detection circuit 5. It has comparators 7 and 9 that detect the load current (or load voltage) and compares its detection output with the voltage signal Vr, and when the detection output exceeds the level of the voltage signal Vr, the control circuit 3 and 10 Load current (or load voltage) to the current voltage generator 4
The output adjustment device is configured to generate a feedback signal for decreasing the voltage, and the reference voltage setting circuit 8 is a variable voltage generator that increases or decreases in response to the output voltage (or output current) of the current voltage generator 4. A first signal source 2 that generates a voltage signal Vs
and a second signal source 1 that generates a constant voltage signal Vc.
1, and an inverting amplifier 14 that obtains a variable inverted voltage signal by inverting the polarity of the variable voltage signal Vs,
a plurality of semiconductor switching elements S to which a variable voltage signal Vs, a constant voltage signal Vc and a variable inversion voltage signal are respectively input from the first signal source 2, second signal source 11 and inverting amplifier 14; a switch 13 that turns on and off the semiconductor switching elements S according to a predetermined combination;
and a summing amplifier 15 that synthesizes the voltage signals Vs, Vc output from the semiconductor switching elements S turned on by the switch 13 to form a plurality of patterns of signals. An output adjustment device characterized in that the formed signal is sent out as a reference voltage signal Vr corresponding to the maximum current (or maximum voltage) supplied to the load.