Current testing circuit and testing method

Abstract

The present invention belongs to the technical field of integrated circuits, and particularly relates to a current testing circuit and a testing method. Among them, the current testing circuit includes: a current source having a current output terminal with adjustable output current magnitude, and the current output terminal is used to connect to the tested pin of the chip under test; a comparator, the non-inverting input terminal is used to connect to a preset reference voltage, the inverting input terminal is used to connect to the tested pin, and the output terminal is the testing terminal. The present invention determines the current value of the tested pin by adjusting the magnitude of the current output by the current source and recording the flip point of the output signal of the comparator, converting the analog quantity test into a functional test, and can conveniently detect the current value of the tested pin of the chip under test.

Description

Technical Field

[0001] The present invention belongs to the technical field of integrated circuits, and particularly relates to a current test circuit and a test method. Background Art

[0002] Measuring current by applying voltage is a commonly used method in chip analog quantity testing. Generally, a PMU (Precision Measurement Unit) is used to apply the required voltage to the chip pins, and the corresponding current is measured by the PMU. For example, if it is necessary to measure the current generated by a chip pin at 0.5V, the PMU is used to apply a 0.5V voltage to the chip pin, and the current of the pin at this time is measured.

[0003] Since the above method requires applying voltage once and measuring current once, there is no problem when measuring a small amount of current for a single chip single pin. However, when it is necessary to measure current units tens of thousands or even millions of times, since the PMU measures analog quantities, there will obviously be problems of time-consuming and laborious, which is not conducive to the test work of a large number of chips. Summary of the Invention

[0004] Aiming at the technical problems of time-consuming and laborious existing in the test method of measuring current by applying voltage, the purpose of the present invention is to provide a current test circuit and a test method.

[0005] A current test circuit includes:

[0006] A current source having a current output terminal with adjustable output current magnitude, and the current output terminal is used to connect to the measured pin of the chip to be measured;

[0007] A comparator, the non-inverting input terminal is used to connect to a preset reference voltage, the inverting input terminal is used to connect to the measured pin, and the output terminal is the test terminal.

[0008] When there are at least two measured pins, there are at least two comparators, and the inverting input terminal of each comparator is connected to a corresponding measured pin;

[0009] The current output terminals of the current source are respectively connected to each measured pin.

[0010] A current test method includes using the current test circuit to test the current value of the measured pin of the chip to be measured, and specifically includes the following steps:

[0011] Connect the current output terminal of the current source to the measured pin of the chip to be measured;

[0012] Connect the non-inverting input terminal of the comparator to a preset reference voltage, and the inverting input terminal to the measured pin;

[0013] Apply different test currents to the pin under test through the current source, and record the test current when the signal at the output terminal of the comparator flips, which is the current value of the pin under test.

[0014] Optionally, applying different test currents to the pin under test through the current source includes:

[0015] Applying different test currents starts from a preset initial current value, increases the test current according to a preset current increment value to obtain a new test current until a preset current end value is reached.

[0016] Optionally, when there are at least two pins under test:

[0017] Apply the initial current value to multiple pins under test simultaneously through the current source, record the signals at the output terminals of at least two comparators to obtain a set of test signals;

[0018] Increase the initial current value according to the current increment value to obtain a new test current and apply it to multiple pins under test simultaneously, and sequentially record the signals at the output terminals of the comparators until the current end value is applied, finally obtaining multiple sets of test signals;

[0019] Form a current test signal matrix with multiple sets of the test signals as elements, with the test current and the pins under test as rows and columns. By checking the flip points of the test signals of each pin under test, the current value of the pin under test can be obtained.

[0020] Optionally, at least two pins under test are divided into at least two groups;

[0021] There are at least two current sources, and each current source is correspondingly connected to each pin under test within the same group.

[0022] Optionally, output different current units inside the chip under test to the pins under test;

[0023] Apply different excitations to the chip under test, and at the same time apply different test currents to the pins under test through the current source, record the signals at the output terminals of the comparators corresponding to different test currents under different excitations to obtain multiple sets of test signals;

[0024] Form a current test signal matrix with multiple sets of the test signals as elements, with the test current and the applied excitation as rows and columns. By checking the flip points of the test signals of the pins under test, the current value of the pin under test can be obtained.

[0025] Optionally, connecting the non-inverting input terminal of the comparator to a preset reference voltage includes:

[0026] Connect the non-inverting input terminal of the comparator to the voltage output terminal of a voltage source that has an adjustable output voltage.

[0027] The positive progressive effect of the present invention is as follows: The present invention adopts a current test circuit and a test method. By adjusting the magnitude of the current output by the current source and recording the flip point of the output signal of the comparator, the current value of the measured pin is determined, transforming the analog quantity test into a functional test, and it is very convenient to detect the current value of the measured pin of the chip under test. Especially when a measured pin of the chip under test can output multiple different currents, the test efficiency can be significantly improved by the current test circuit and test method of the present invention. Description of the Drawings

[0028] Figure 1 It is a schematic diagram of a circuit connection of the present invention. Detailed Embodiments

[0029] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below with reference to specific illustrations.

[0030] Refer to Figure 1 , A current test circuit includes a current source 100 and a comparator 200. The current source 100 has a current output terminal with an adjustable output current magnitude, and the current output terminal is used to connect to the measured pin of the chip under test 300. The non-inverting input terminal of the comparator 200 is used to connect to a preset reference voltage Vref, the inverting input terminal of the comparator 200 is used to connect to the measured pin of the chip under test 300, and the output terminal of the comparator 200 is the test terminal OUT.

[0031] When there are at least two measured pins, there are at least two comparators 200, and the inverting input terminal of each comparator 200 is connected to a corresponding measured pin. At this time, the reference voltage Vref of each comparator 200 can be the same or set to be different according to the scenario requirements. The current output terminal of the current source 100 is respectively connected to each measured pin. These at least two measured pins can be measured pins on different chips under test 300, or different measured pins on the same chip under test 300.

[0032] A current test method includes using the current test circuit of the present invention to test the current value of the measured pin of the chip under test 300, specifically including the following steps:

[0033] S1, Circuit connection: Connect the current output terminal of the current source 100 to the measured pin of the chip under test 300, connect the non-inverting input terminal of the comparator 200 to a preset reference voltage Vref, and connect the inverting input terminal of the comparator 200 to the measured pin of the chip under test 300.

[0034] The reference voltage Vref in this step is the voltage value corresponding to the current value of the pin under test to be measured. For example, as Figure 1 shown, to measure the current generated by the first pin in the upper left corner of the chip under test 300 at 0.5V, the non-inverting input terminal of the comparator 200 is connected to a reference voltage Vref of 0.5V.

[0035] In one embodiment, connecting the non-inverting input terminal of the comparator 200 to a preset reference voltage Vref includes: connecting the non-inverting input terminal of the comparator 200 to the voltage output terminal of a voltage source, and the voltage source has an adjustable output voltage.

[0036] The reference voltage Vref in this embodiment can be output by a voltage source, and the voltage source is preferably a voltage source with an adjustable output voltage. For example, to measure the current generated by the first pin in the upper left corner of the chip under test 300 at 0.5V, a reference voltage Vref of 0.5V is output to the non-inverting input terminal of the comparator 200 through the voltage source. To measure the current generated by the first pin in the upper left corner of the chip under test 300 at 1V, a reference voltage Vref of 1V is output to the non-inverting input terminal of the comparator 200 through the voltage source.

[0037] S2. Current test: Apply different test currents to the pin under test through the current source 100, and record the test current when the signal at the output terminal of the comparator 200 flips, which is the current value of the pin under test.

[0038] For example, to measure the current generated by the first pin in the upper left corner of the chip under test 300 at 0.5V, when the test current applied by the current source 100 is 100uA, the signal at the output terminal of the comparator 200 flips, indicating that the current of the pin under test at 0.5V is 100uA.

[0039] In one embodiment, applying different test currents to the pin under test through the current source 100 includes:

[0040] Applying different test currents starts from a preset initial current value, increases the test current according to a preset current increment value to obtain a new test current until a preset current end value. That is, the test current applied by the current source 100 to the pin under test is:

[0041]

[0042] where i ranges from 1 to n, is the preset initial current value, is the preset current end value, and A is the preset current increment value.

[0043] For example, to measure the current generated by the first pin in the upper left corner of the chip under test 300 at 0.5V, a test current is applied to the pin under test through the current source 100, and the application is carried out sequentially from 0uA to 1000uA, that is is 0uA, is 1000uA, and A can be 1uA, 10uA or 100uA according to requirements.

[0044] After the above method, it is simpler and more convenient to detect a certain pin under test of a chip under test 300. Especially when the chip under test 300 modifies some internal parameter configurations, the pin under test may present different currents, that is, when a pin under test may output multiple different currents, in the way of current scanning from the initial current value to the end current value through the test current in the present invention, the test efficiency can be significantly improved.

[0045] In one embodiment, in the scenario where there are at least two pins under test, the current test method for the above scenario is as follows:

[0046] There are at least two comparators 200, and the inverting input terminal of each comparator 200 is connected to a corresponding pin under test. At this time, the reference voltage Vref of each comparator 200 can be the same or set differently according to the scenario requirements. The current output terminals of the current source 100 are respectively connected to each pin under test. The at least two pins under test can be pins under test on different chips under test 300, or different pins under test on the same chip under test 300.

[0047] The current source 100 simultaneously applies the initial current value to multiple pins under test, records the output signals of at least two comparators 200 to obtain a set of test signals; increases the initial current value according to the current increment to obtain a new test current and simultaneously applies it to multiple pins under test, and sequentially records the output signals of the comparators 200 until the end current value is applied, and finally obtains multiple sets of test signals; forms a current test signal matrix with multiple sets of test signals with the test current and the pins under test as rows and columns and the test signals as elements, and by checking the turning points of the test signals of each pin under test, the current value of the pin under test can be obtained.

[0048] For example, to perform a current test on seven pins under test, the seven pins under test are i1 to i7 respectively. The inverting inputs of seven comparators 200 are connected to a corresponding pin under test. The reference voltage Vref of each comparator 200 is set respectively. The current output terminals of the current source 100 are connected to each pin under test respectively. The initial value of the current of the current source 100 is set to 1 uA, the end value of the current is 20 uA, and the current increment is 1 uA. The current source 100 sequentially supplies test currents of 1 uA / 2 uA / 3 uA… / 20 uA to the seven pins under test simultaneously, and 20 groups of test signals are measured from the output terminals of the comparators 200. The 20 groups of measured test signals are formed into a matrix as shown in the following table:

[0049]

[0050] Through this matrix, the currents of the seven pins under test i1 to i7 can be easily obtained as 8 uA, 3 uA, 10 uA, 2 uA, 15 uA, 17 uA, and 13 uA respectively.

[0051] When a large number of pins under test need to be tested, the pins under test can be grouped, and the current source 100 supplies currents to the pins under test in the corresponding group respectively.

[0052] In one embodiment, when there is one pin under test and there are multiple current units inside the chip under test, the current test method for the above scenario is as follows:

[0053] Output different current units inside the chip under test to the same preset pin under test. The current output terminal of the current source 100 is connected to this pin under test, and the inverting input of the comparator 200 is connected to this pin under test.

[0054] Apply different excitations to the chip under test, and perform the operation of applying different test currents under different excitations. That is, when applying a certain excitation to the chip under test, apply the initial current value to the pin under test through the current source 100, record the signal at the output terminal of the comparator 200, and obtain a set of test signals. Increase the initial current value according to the current increment value to obtain a new test current and apply it to the pin under test, and record the signals at the output terminal of the comparator 200 in turn until the end current value is applied, and finally obtain multiple sets of test signals. Form a current test signal matrix with multiple sets of test signals using the test current and the applied excitation as rows and columns and the test signals as elements. By checking the flip point of the test signal of the pin under test, the current value of the pin under test can be obtained. For example, apply seven different excitations to the chip under test, where the different excitations are j1 to j7 respectively. The current output terminal of the current source 100 is connected to the pin under test, and the inverting input terminal of the comparator 200 is connected to the pin under test. Set the initial current value of the current source 100 to 1uA, the end current value to 20uA, and the current increment value to 1uA.

[0055] Under seven different excitation scenarios, the current source 100 sequentially delivers test currents of 1uA / 2 uA / 3 uA… / 20 uA to the pin under test, and 20 sets of test signals are measured from the output terminal of the comparator 200. The 20 sets of measured test signals are formed into a matrix as shown in the following table:

[0056]

[0057] Through this matrix, it is easy to obtain that the current values of the pin under test under seven different excitations are 8uA, 3uA, 10uA, 2uA, 15uA, 17uA, and 13uA respectively.

[0058] The above shows and describes the basic principle, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A current test circuit, characterized in that: include: A current source having a current output terminal with an adjustable output current, wherein the current output terminal is used to be connected to a tested pin of the tested chip; A comparator, wherein the in-phase input terminal is used to connect to a preset reference voltage, the inverting input terminal is used to connect to the pin to be tested, and the output terminal is a test terminal; Different test currents are applied to the tested pin through the current source, and the test current recorded when the output signal of the comparator is flipped is the current value of the tested pin.

2. The current test circuit according to claim 1, characterized in that: When there are at least two pins to be tested, there are at least two comparators, and the inverting input terminal of each comparator is connected to a corresponding pin to be tested; The current output end of the current source is connected to each of the tested pins respectively.

3. A current testing method, characterized in that: The method comprises using the current test circuit of claim 1 or 2 to test the chip under test, specifically comprising the following steps: Connect the current output terminal of the current source to the tested pin of the tested chip; Connect the non-inverting input terminal of the comparator to a preset reference voltage, and connect the inverting input terminal to the pin to be tested; Different test currents are applied to the tested pin through the current source, and the test current recorded when the output signal of the comparator is flipped is the current value of the tested pin.

4. The current testing method according to claim 3, characterized in that: The applying different test currents to the tested pin by the current source comprises: Applying different test currents starts from a preset current initial value, and the test current is increased according to a preset current increase value to obtain a new test current, until a preset current end value is reached.

5. The current testing method according to claim 4, characterized in that: When there are at least two pins to be tested: Applying the initial current value to the plurality of the tested pins simultaneously through the current source, recording the output terminal signals of at least two of the comparators, and obtaining a set of test signals; Increasing the initial current value according to the current increase value to obtain a new test current and applying it to the plurality of tested pins at the same time, recording the output terminal signals of the comparator in sequence until the current end value is applied, and finally obtaining a plurality of test signals; Multiple groups of the test signals are formed into a current test signal matrix with the test current and the tested pins as rows and columns and the test signals as elements. The current value of the tested pin can be obtained by checking the flip point of the test signal of each tested pin.

6. The current testing method according to claim 5, characterized in that: At least two of the tested pins are divided into at least two groups; There are at least two current sources, and each current source is correspondingly connected to each of the tested pins in the same group.

7. The current testing method according to claim 4, characterized in that: Outputting different current units inside the chip under test to the pin under test; Apply different excitations to the chip under test, and at the same time apply different test currents to the pin under test through the current source, and record the comparator output terminal signals corresponding to different test currents under different excitations to obtain multiple groups of test signals; Multiple groups of the test signals are arranged with the test current and the applied excitation as rows and columns and the test signals as elements to form a current test signal matrix. The current value of the tested pin can be obtained by checking the flip point of the test signal of the tested pin.

8. The current testing method according to claim 3, characterized in that: The step of connecting the non-inverting input terminal of the comparator to a preset reference voltage comprises: The non-inverting input terminal of the comparator is connected to the voltage output terminal of a voltage source, and the voltage source has an adjustable output voltage.

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