JPS62202211A - Power source testing equipment - Google Patents

Abstract

PURPOSE:To automatize decision of the output characteristic by determining upper and lower limits of the allowable range of a power source and comparing the power source output, which changes in accordance with the load condition, with upper and lower limit values. CONSTITUTION:If the output of a D/A converter 11 is changed stepwise, an electronic load 3 takes a load current from a power source 1 to be checked. In this case, the output state of the power source 1 is compared with allowable upper and lower limit values fH and fL of D/A converters 12 and 13, which are changed synchronously with the output of the D/A converter 11, by comparators 14 and 15. If the output state is deviated from the allowable range, outputs of comparators 14 and 15 are changed, for example, from '0' to '1' to issue an abnormality signal EOP, and D/A converters 12 and 13 issue alarm signals 1 and 2 respectively, and comparators 14 and 15 stop the sweep operation of D/A converters 12 and 13. In this constitution, the output characteristic of the power source is compared with upper and lower limit values while changing the load state of the power source after the load condition is set preliminarily, thus decided automatically and quickly whether the power source to be checked is good or not.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a test device for a power supply whose output voltage changes depending on load conditions (for example, a power supply with constant current characteristics). The present invention relates to a power supply testing device that automatically performs pass/fail determination.

(Prior Art) Reliability and output characteristics of power supplies, which are sources for supplying power to various loads such as electronic circuits (including analog circuits and digital circuits), pose problems.

If the power supply breaks, excessive voltage will be applied to the electronic circuit, which may be destroyed.In the event of an abnormality such as a negative IVJ short circuit, the output current must be cut or the output voltage must be lowered. As for the load, the power supply itself may be destroyed due to heat generation. For this reason, the power supply is usually provided with output characteristics as shown in FIG. (a) is ``7 characteristics of ko'', (b) is ``7 characteristics of deformed ko'', (
C) is the seventh characteristic of F. In the figure, the vertical axis is the voltage V
, the horizontal axis is the current I. In both characteristics, the power supply voltage remains constant until the output current reaches a certain value, but as the output current increases further, the voltage decreases to protect the power supply.

Conventionally, when determining the quality of a power supply, a tolerance range (the shaded area in the diagram) is determined in advance for the output of the power supply as shown in Figure 4, and it is checked whether the output characteristics of the power supply under test are within the tolerance range. We judge whether something is good or bad. FIG. 5 is a diagram showing a conventional power supply testing circuit. Power supply 1 to be tested is shunt 2
is connected to the electronic load 3 via D/
The load current of the Δ converter 4 is controlled by J. Here, the electronic load 3 is a device configured to control the load current set from the D/A converter 1 regardless of the output voltage value of the power supply 1. The output voltage of the power supply 1 and the load current flowing through the shunt 2 are input to a Δ/(] converter 5, respectively.

To explain the operation of the test circuit configured in this way, first, a load setting signal is sent from the D/A converter 4 to the electronic load 3, and the state of the load is sequentially changed as shown in FIG.

The output states (voltage V, lightning current) of the power supply 1 to be tested at this time are sequentially sent to the A/D converter 5, and each is converted into digital data and displayed. The operator plots the output voltage and output current values to determine whether the output characteristics are within an acceptable range. Or change the voltage and current to A/
Instead of reading with the D converter 5, a method may also be used in which the output characteristics as shown in FIG. 4 are recorded with an X-Y recorder and it is determined whether the output characteristics are within the permissible range.

(Problems to be Solved by the Invention) According to the conventional power supply inspection method as described above, the process of measuring the load conditions of the streetcar and load conditions → measuring the power supply output characteristics → determining whether the output characteristics are within the allowable range is carried out. This required a considerable number of inspection man-hours.

The present invention has been made in view of these points, and
The purpose is to realize a power supply testing device that can automate the determination of the output characteristics of a power supply and shorten the number of inspection steps.

(Means for Solving the Problems) The present invention, which solves the above-mentioned problems, predetermines the upper and lower limits of the allowable range of the output characteristics of the power supply, and when the electronic load connected to the power supply is changed. The device is characterized by a port configured to compare the voltage change of the power source with the upper and lower limits of the permissible range in correspondence with the current change, and output an alarm when the permissible range is exceeded.

(Operation) In the present invention, the upper and lower limits of the allowable range of the power supply are determined in advance, and the power supply output, which is changing depending on the load condition, is compared with the upper and lower limits.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. Components that are the same as those in FIG. 5 are designated by the same numbers. In the figure, reference numeral 11 denotes a first function D/D, which has an automatic sweep function that changes the output in synchronization with the input clock.
The output of the A converter is given to the electronic load 3 to gradually change the load state. 12 is a second function D/A converter having a sweep function that generates the upper limit of the power output characteristic in synchronization with the input clock, and 13 has a sweep function that generates the lower limit of the power output characteristic in synchronization with the input clock. This is the third function D/A converter.

The synchronization clock is the first to third function D/
Since it is commonly input to the A converters 11 to 13, the outputs of these function D/A converters 11 to 13 change in synchronization. The function D/A converter is designed to be able to change its output in advance, and its output changes sequentially every time it receives an input clock.

14 is a comparator that receives the output voltage of the power supply under test 1 at one input and the sweep output of the second function D/A converter 12 at the other input, and 15 receives the output of the power supply under test 1 at one input. This is a comparator which receives the voltage at the other input of the sweep output of the third function D/A converter 13. The outputs of these comparators 14, 15 are respectively the second . input to the third function D/A converter 12.13, and the second function D/A converter 12.13. The third function D/A converter 12.13 outputs an alarm signal indicating malfunction of the power supply 1 to be tested.

The operation of the device configured as described above will be explained as follows.

Now, if the output of the first function D/A converter 11 is changed stepwise as shown in FIG. 2(a), the electronic load 3 will be changed from the power supply under test 1 to Drop the load current. During this time, the output state of the power supply under test 1 is]
into the comparators 14 and 15, Fig. 2 (c), <2)
It is compared with an upper limit value and a lower limit value that change in synchronization with the output of the first function D/A converter 11 as shown in FIG. Here, the output waveform shown in FIG. 2 (c) is the allowable upper limit [H] in FIG. 2 (b), and the output waveform shown in FIG. 2 (d) is
The allowable lower limit value shown in Fig. 2 (e) is shown.

If the output of the power supply under test 1 is within the permissible range,
Since the comparators 14 and 15 do not operate until the sweep of the function D/A converters 12 and 13 is completed, it can be determined that the power supply under test 1 is "good".If the output of the power supply under test 1 is If the upper limit or lower limit is exceeded, the output of the comparator 14.15 changes from, for example, "o" to "1":I, and the normal signal EOP is sent to the function D/A converter 12.13.
give to

As a result, the second function l')/A converter 12
outputs a warning signal, alarm 1, and the third function D/A converter 13 outputs a warning signal, alarm 2, and stops the sweep operation. These alarm signals alarm 1. By ringing a bell using alarm 2, or by giving it as an interrupt signal to a combi coater, etc., the authenticity determination can be displayed on a CRT or printed on a printer, allowing the operator to inspect it. I can let you know the results.

Then, if necessary, replace the power supply to be tested with another one and repeat the same test.

As described above, according to the present invention, as long as the load conditions are set in advance, the subsequent measurement of the power output characteristics and the determination of whether they are within the allowable range are all automatically performed.
There is no need for man-hours for operating sounds, and inspection time is significantly reduced.

In the above explanation, the load characteristics of the power supply are shown in Figure 3 (b).
Although the case of the seven characteristics of the Zupah deformation shown in FIG. It can be similarly applied when testing a power supply with the 7 characteristics shown in Figure 3 (A) or the 7 characteristics shown in Figure 3 (C). For example, The characteristics shown in (c) may be set in advance in the function D/A converters 12 and 13.

(Effects of the Invention) As described above in detail, according to the present invention, the upper and lower limits of the allowable range of the output characteristics of a power source are determined in advance, and the output characteristics are increased while changing the load condition of the power source. By comparing with the lower limit value, the quality of the power supply to be tested can be determined automatically and at high speed, and the number of testing steps can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram showing one embodiment of the present invention, and FIG.
Figure 3 shows the operating waveforms of each part, Figure 3 shows the output characteristics of the power supply, Figure 4 shows the allowable range of power output, and Figure 5
The figure shows a conventional power supply testing circuit. 1... Power supply to be inspected 2... Shunt 3... Electronic load 4... D/A converter 5... A/D converter 11-13... Function D/A converter 14. 1
5... Comparator patent applicant Yokogawa Hokushin Electric Co., Ltd. 1st representative Patent attorney Shinsuke Ozawa 2nd (a) Function D/A #1 output (b) Current (c) Function D/A I2 Output (E) Figure 3 (A) (B)
Hiroshi) Figure 4 ■ Figure 5

Claims (1)

[Claims] The upper and lower limits of the permissible range of the output characteristics of the power supply are determined in advance, and the voltage change of the power supply when the electronic load connected to the power supply is changed is made to correspond to the upper and lower limits of the permissible range and the current change, respectively. A power supply testing device characterized in that it is configured to compare and output an alarm when it is out of an allowable range.