CN211669274U - Current measurement auxiliary device - Google Patents

Abstract

The utility model provides an auxiliary device for current measurement, comprising: a current sampling resistor, which is connected in series to a load circuit of a target power supply to be measured; a first amplifying module, two input ends of the first amplifying module are respectively connected to the current The two ends of the sampling resistor are connected; the second amplifying module, the input end of the second amplifying module is connected with the output end of the first amplifying module; the maximum value capturing module, the input end of the maximum value capturing module is connected with the output end of the second amplifying module an effective voltage acquisition module, the input terminal of the effective voltage acquisition module is connected with the output terminal of the second amplifying module; the maximum voltage acquisition module, the input terminal of the maximum voltage acquisition module is connected with the output terminal of the maximum voltage acquisition module. The limitation of the utility model is small, and the load current of the tested power supply can be obtained quickly and conveniently based on the resistance value of the current sampling resistor.

Description

Auxiliary device for current measurement

technical field

The utility model relates to the technical field of integrated circuit testing, in particular to an auxiliary device for current measurement.

Background technique

With the development of chip technology, the scale of the chip is getting larger and the speed is getting higher and higher, which puts forward the requirements of low voltage and high current for the power supply. Measurement. At present, the current test instruments on the market include digital multimeters, current test power supplies, and oscilloscope current probes. Among them, the defect of the digital multimeter is that the equivalent impedance of the lead is large, which is easy to cause abnormality of the power supply under test; the defect of the test power supply with current is that the power-on sequence is uncontrollable, and the power supply that requires the power-on sequence cannot meet the requirements; the oscilloscope current probe has excellent performance , The data is comprehensive, but the disadvantage is that it requires a thicker test line, it is difficult to weld a small board, and the oscilloscope current probe is expensive. It can be seen that these current testing instruments for measuring the load current of the power supply have great limitations and are inconvenient for the measurement of the load current.

Utility model content

The utility model provides an auxiliary device for current measurement, the purpose of which is to solve the problem that the current measurement instrument has large limitations and is inconvenient to measure the load current.

In order to achieve the above purpose, an embodiment of the present utility model provides an auxiliary device for current measurement, including:

a current sampling resistor, which is connected in series to the load circuit of the target power supply under test;

a first amplifying module, wherein two input ends of the first amplifying module are respectively connected to both ends of the current sampling resistor, and the first amplifying module performs differential amplification processing on the voltage signals at both ends of the current sampling resistor;

a second amplifying module, the input end of the second amplifying module is connected to the output end of the first amplifying module, and the second amplifying module performs operational amplification processing on the voltage signal output by the first amplifying module;

The maximum value capture module, the input end of the maximum value capture module is connected to the output end of the second amplification module, the maximum value capture module captures the maximum value of the voltage signal output by the second amplification module, and captures the maximum value of the voltage signal output by the second amplification module. The maximum value is used as the output value of the maximum value capture module;

an effective voltage acquisition module, the input terminal of the effective voltage acquisition module is connected to the output terminal of the second amplification module, and the effective voltage acquisition module acquires and displays the effective value of the voltage signal output by the second amplification module;

A maximum voltage acquisition module, the input terminal of the maximum voltage acquisition module is connected to the output terminal of the maximum value capture module, and the maximum voltage acquisition module acquires and displays the output value of the maximum value capture module.

The above-mentioned scheme of the present utility model has at least the following beneficial effects:

In the embodiment of the present invention, by connecting the current sampling resistor in series with the load circuit of the target power supply under test, the voltage signal at both ends of the current sampling resistor is differentially amplified by the first amplifying module and then converted into a single-ended signal and output to the second Amplifying module, after receiving the voltage signal output by the first amplifying module, the second amplifying module performs operational amplification processing on the voltage signal, and outputs it to the maximum value capturing module and the effective voltage obtaining module, at this time the effective voltage obtaining module can obtain the And display the effective value of the voltage signal output by the second amplifying module, which is convenient to obtain the effective value of the load current of the power supply under test based on the resistance value of the current sampling resistor and the magnification of the first amplifying module and the first amplifying module, while the maximum value The capture module can capture the maximum value of the voltage signal output by the second amplification module, and output the maximum value to the maximum voltage acquisition module, so as to be convenient based on the resistance value of the current sampling resistor and the amplification factor of the first amplification module and the first amplification module, Get the maximum value of the load current of the power supply under test. Among them, since the series connection of the current sampling resistor will not destroy the path of the power supply under test, it will not affect the original power-on sequence of the power supply under test, so there is no power-on sequence problem when measuring the current with the current test power supply; at the same time, the first amplifying module And the magnification of the second amplifying module can make the resistance value of the current sampling resistor very small, and the test line is not connected in series in the load circuit, so there is no problem of large line impedance when the digital multimeter measures current, and there is no oscilloscope current. The probe measurement requires a large board space, so the current measurement auxiliary device of the present invention has small limitations compared to the current current measurement instruments.

Description of drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are just some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

Fig. 1 is one of the structural schematic diagrams of the current measurement auxiliary device according to the embodiment of the present invention;

2 is a schematic circuit diagram of a first amplifying module according to an embodiment of the present invention;

Fig. 3 is the circuit schematic diagram of the maximum value capture module of the embodiment of the present invention;

4 is a schematic circuit diagram of a second amplifying module according to an embodiment of the present invention;

5 is the second structural schematic diagram of the current measurement auxiliary device according to the embodiment of the present invention;

6 is a schematic diagram of a circuit structure of a capture reset module according to an embodiment of the present invention;

7 is a schematic diagram of a circuit structure of a clock signal generating module according to an embodiment of the present invention.

[Description of reference numerals]

1. Current sampling resistor; 2. The first amplification module; 3. The second amplification module; 4. The maximum value capture module; 5. The effective voltage acquisition module; 6. The maximum voltage acquisition module; 7. The clock signal trigger module; 8. Clock signal generation module; 9. Range switching module; 10. Capture reset module.

Detailed ways

The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are part of the embodiments of the present utility model, not all of the embodiments. . It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

As shown in FIG. 1 , an embodiment of the present invention provides an auxiliary device for current measurement, including: a current sampling resistor 1, a first amplification module 2, a second amplification module 3, a maximum value capture module 4, and an effective voltage acquisition module 5 and the maximum voltage acquisition module 6.

Wherein, the current sampling resistor 1 is connected in series with the load circuit of the target power supply under test; the two input ends of the first amplifying module 2 are respectively connected with both ends of the current sampling resistor 1, and the first amplifying The module 2 performs differential amplification on the voltage signal at both ends of the current sampling resistor 1; the input end of the second amplifying module 3 is connected to the output end of the first amplifying module 2, and the second amplifying module 3 is used for The voltage signal output by the first amplification module 2 is subjected to operational amplification processing; the input end of the maximum value capture module 4 is connected to the output end of the second amplification module 3, and the maximum value capture module 4 captures the second The maximum value of the voltage signal output by the amplification module 3, and the captured maximum value is used as the output value of the maximum value capture module 4; the input end of the effective voltage acquisition module 5 and the output end of the second amplification module 3 connected, the effective voltage acquisition module 5 acquires and displays the effective value of the voltage signal output by the second amplification module 3; the input end of the maximum voltage acquisition module 6 is connected with the output end of the maximum value capture module 4, The maximum voltage acquisition module 6 acquires and displays the output value of the maximum voltage acquisition module 4 .

Wherein, in the embodiment of the present invention, the above-mentioned target power supply under test may be any one of a plurality of power supplies under test, that is, the load current of any power supply under test among the plurality of power supplies under test can be selected to be measured. It should be noted that the above-mentioned power supply under test refers to the power supply that needs to measure the load current, and the power supply can be the power supply of the chip. It can be understood that when there are multiple power supplies under test, the measurement of the multiple power supplies under test can be completed by measuring the power supplies under test one by one.

Specifically, in order to realize the measurement of multiple power supplies under test, a current sampling resistor is connected in series to the load circuit of each power supply under test in the above multiple power supplies under test, and both ends of the current sampling resistor are provided with a A switch contact. In order to facilitate the measurement of the load current of the target power supply under test, the two input ends of the first amplifying module are provided with second switch contacts, and the two second switch contacts of the first amplifying module are connected to the target. The two first switch contacts of the current sampling resistor in the load circuit of the power supply under test are in one-to-one contact and conduct, that is, the two input ends of the first amplifying module are connected to the current sampling in the load circuit of the target power supply under test. Both ends of the resistor are connected to perform differential amplification processing on the voltage signal at both ends of the current sampling resistor.

Among them, in the embodiment of the present utility model, the above-mentioned first amplifying module is mainly used to differentially amplify the voltage signal at both ends of the current sampling resistor in the load circuit of the target power supply under test, and the voltage signal is processed by the first amplifying module. After amplification, it is converted to single-ended signal output.

Specifically, the circuit schematic diagram of the above-mentioned first amplifying module may be the structure shown in FIG. 2 . The two input ends of the differential amplifier A1 in FIG. 2 are connected to the two ends of the current sampling resistor R _SENSE , and V _out is the first The voltage signal output by the amplifying module, the inverted triangle in Figure 2 represents grounding.

It should be noted that, in order to avoid introducing too much noise when amplifying the voltage signal across the current sampling resistor and affecting the accuracy of the measurement, the amplification factor of the voltage signal across the current sampling resistor by the first amplifying module cannot be too large. , and in order to ensure that the resistance value of the current sampling resistor can be small, in the embodiment of the present invention, a second amplifying module is arranged after the first amplifying module, and the second amplifying module is mainly used to perform the voltage signal output by the first amplifying module. Operational amplification processing, so that when the resistance value of the current sampling resistor is very small, the effective voltage acquisition module and the maximum voltage acquisition module can still obtain a relatively obvious voltage value, so as to avoid the abnormality of the measured power supply caused by the excessive resistance value of the current sampling resistor In the case of , complete the measurement of the power under test.

It is worth mentioning that, due to the existence of the first amplifying module, the measurement of the load current can be completed without connecting a test wire in series in the load circuit. It should be noted that the series connection of the current sampling resistor will not destroy the load path and will not affect the original power-on sequence of the tested power supply, so there is no power-on sequence problem when measuring the current with the current test power supply; at the same time, the first amplification The amplification factor of the module and the second amplifying module can make the resistance value of the current sampling resistor small, and no test line is connected in series in the load circuit, so there is no problem of large line impedance when the digital multimeter measures current, and there is no oscilloscope. The current probe measurement requires a large board space, so the current measurement auxiliary device of the present invention has small limitations compared to the current current testing instruments.

Among them, in the embodiment of the present invention, the above-mentioned effective voltage acquisition module is mainly used to acquire the effective value of the voltage signal output by the second amplifying module, so as to facilitate the acquisition of the target measured power supply based on the resistance value of the current sampling resistor. RMS value of load current. For example, assuming that the effective value obtained by the effective voltage acquisition module is V1, the effective value of the load current of the target power supply under test can be obtained through the formula V1/(A1*A2). Wherein, A1 is the magnification of the first amplifying module, and A2 is the magnification of the second amplifying module.

As a preferred example, the above-mentioned effective voltage acquisition module may be a device such as an oscilloscope or a multimeter, which can obtain the effective value of the voltage signal through the voltage signal output by the second amplifying module.

It should be noted that measuring the load current of the power supply under test includes measuring the effective value and the maximum value of the load current. Among them, the maximum value is used to determine the maximum current output capability of the power supply under test, and the effective value is used to calculate the power consumption of the load of the power supply under test. Therefore, after obtaining the effective value of the load current of the power supply under test according to the effective value obtained by the effective voltage acquisition module, it is also necessary to obtain the maximum value of the load current of the power supply under test. Based on this, the above-mentioned current measurement auxiliary device includes a maximum value acquisition module and a maximum voltage acquisition module.

Specifically, in the embodiment of the present invention, the above-mentioned maximum value capturing module is mainly used to capture the maximum value of the voltage signal output by the second amplifying module, and output the maximum value.

Specifically, the circuit schematic diagram of the above-mentioned maximum value capture module may be the structure shown in FIG. 3 , V _{in in} FIG. 3 is the voltage signal output by the second amplifying module, resistor R ₂ and operational amplifier A in FIG. 3 _1. The diode D ₁ and the capacitor C ₁ form a charging function, the switch SW ₁ is used to discharge the capacitor C ₁ , and the operational amplifier A ₂ and the resistor R ₁ are used to feedback the capacitor voltage, so that the capacitor voltage reflects the maximum value of V _in , and V _out is is the maximum value of the voltage signal output by the second amplifying module, and the inverted triangle in FIG. 3 represents grounding. It should be noted that this circuit is a conventional circuit, which has been proved to be stable and reliable through extensive use, so it can be ensured that the maximum value capturing module can obtain the maximum value of the voltage signal output by the second amplifying module.

Among them, in the embodiment of the present utility model, the maximum voltage acquisition module is mainly used to acquire the output value of the maximum value capture module, so as to facilitate obtaining the maximum value of the load current of the target power supply under test based on the resistance value of the current sampling resistor . For example, if the maximum voltage acquisition module obtains the output value of the maximum value capture module as V2, the maximum value of the load current of the target power supply under test can be obtained through the formula V2/(A1*A2). Wherein, A1 is the magnification of the first amplifying module, and A2 is the magnification of the second amplifying module.

As a preferred example, the above-mentioned maximum voltage acquisition module may be a device such as an oscilloscope or a multimeter, which can obtain the maximum value of the voltage signal output by the second amplifying module through the output value of the maximum value capture module.

It can be seen that, in the embodiment of the present invention, the measurement of the load current is completed by connecting a current sampling resistor in series in the load circuit of the target power supply under test. Among them, since the series connection of the current sampling resistor will not destroy the path of the power supply under test, it will not affect the original power-on sequence of the power supply under test, so there is no power-on sequence problem when measuring the current with the current test power supply; at the same time, the first amplifying module And the magnification of the second amplifying module can make the resistance value of the current sampling resistor very small, and the test line is not connected in series in the load circuit, so there is no problem of large line impedance when the digital multimeter measures current, and there is no oscilloscope current. The problem that the probe measurement requires a large board space, so the current measurement auxiliary device of the present invention has small limitations compared to the current current measurement instrument, and can quickly and conveniently obtain the measured value based on the resistance value of the current sampling resistor. The load current of the power supply.

Wherein, in the embodiment of the present invention, the above-mentioned second amplifying module may be implemented by a non-inverting amplifying circuit, that is, the above-mentioned second amplifying module includes a non-inverting amplifying circuit. The input terminal of the non-inverting amplifier circuit is connected to the output terminal of the first amplifier module, and the output terminal of the non-inverting amplifier circuit is respectively connected to the input terminal of the effective voltage acquisition module and the input terminal of the maximum value acquisition module. end connection.

Wherein, the feedback branch of the non-inverting amplifier circuit includes a first feedback resistor, and multiple feedback resistor units connected in series with the first feedback resistor, the multiple feedback resistor units are connected in parallel with each other, and the feedback resistor unit includes A second feedback resistor and a normally open switch connected in series with the second feedback resistor.

It should be noted that the resistance values of the second feedback resistors in the multiple feedback resistor units are different from each other. When the current measurement auxiliary device is in the working state, the normally open switch of one feedback resistor unit in the multiple feedback resistor units is is closed. That is, in the embodiment of the present invention, by selecting different feedback resistance units, the magnification of the second amplifying module can be changed to facilitate the measurement of the load current of the power supply under test. As a preferred example, the above-mentioned non-inverting amplifying circuit can be implemented by the non-inverting amplifying circuit shown in FIG. 4 , wherein V _{in in} FIG. 4 is the voltage signal output by the first amplifying module, and V _out is the second amplifying module The output voltage signal, R ₁ is the input resistance in the same direction, A is the operational amplifier, R ₂ is the first feedback resistance of the feedback branch, R _f1 is the second feedback resistance in the f1 feedback resistance unit, and R _f2 is the first feedback resistance. The second feedback resistance in f2 feedback resistance units, and so on, R _fn is the second feedback resistance in the fnth feedback resistance unit, n is the number of feedback resistance units, and the inverted triangle in FIG. 4 represents grounding.

Wherein, based on the adjustable magnification of the above-mentioned second amplifying module, as shown in FIG. 5 , the above-mentioned current measurement auxiliary device further includes a clock signal trigger module 7, a clock signal generation module 8, a range switching module 9 and a capture reset module 10, In order to combine the adjustment of the magnification of the second amplifying module 3, the measurement of the load current of the power supply under test is completed.

Wherein, the input end of the clock signal trigger module 7 is connected with the output end of the maximum value capture module 4, and the clock signal trigger module 7 compares the output value of the maximum value capture module 4 with a preset value, And when the output value of the maximum value capture module 4 is greater than or equal to the preset value, a clock trigger signal is output; the input end of the clock signal generation module 8 is connected with the output end of the clock signal trigger module 7, The clock signal generation module 8 outputs a clock signal when receiving the clock trigger signal; the input end of the range switching module 9 is connected with the output end of the clock signal generation module 8, and the output end of the range switching module 9 is connected. The terminal is connected to the control terminal of each normally open switch of the second amplifying module 3; the input terminal of the capture reset module 10 is connected to the output terminal of the clock signal trigger module 7, and the reset signal of the capture reset module 10 is connected. The output terminal is connected to the reset signal input terminal of the maximum value capture module 4 , and the capture reset module 10 outputs a reset signal to the maximum value capture module 4 when receiving the clock trigger signal.

It should be noted that the above preset value is related to the maximum voltage value that can be captured by the maximum value capture module (that is, the range of the maximum value capture module), so as to prevent the maximum value capture module from being unable to capture the voltage output by the second amplifying module due to its own reasons. the maximum value of the signal. For example, assuming that the maximum voltage value that can be captured by the maximum value capture module is 4.5 volts, the default value can be 4.35 volts. When the output value of the maximum value capture module reaches saturation (that is, the output value of the maximum value capture module is greater than or equal to the preset value), the clock signal trigger module outputs a clock trigger signal, and the clock signal generation module sends the clock trigger signal to the clock signal according to the clock trigger signal. The range switching module outputs a clock signal, and the range switching module sends a control signal to the control terminals of the normally open switches of the second amplifying module according to the clock signal signal, so as to control the second amplifying module to reduce the magnification, so as to ensure that the maximum value capture module can capture The maximum value of the voltage signal output by the second amplifying module. Of course, it should be noted that the clock trigger signal output by the clock signal trigger module will also reach the capture reset module, so that the capture reset module can output a reset signal to the maximum value capture module, and reset the value captured by the maximum value capture module to zero, so that in the first After the amplification factor of the second amplifying module is adjusted, the maximum value of the voltage signal output by the second amplifying module is recaptured. It should be further explained that the initial magnification of the second amplification module is the maximum magnification, and when the magnification of the second method module is adjusted, the normally open switches in each feedback resistor unit will be controlled in the order of magnification from large to small. status.

Specifically, in order to facilitate the control of the state of the normally open switches in each feedback resistance unit, the normally open switches in the second amplifier module may be a group of normally open contacts of the first relay, that is, each normally open switch is the first relay A set of normally open contacts. In order to facilitate sending a control signal to the control terminal of the first relay, the range switching module may include a counter and a decoder, the input terminal of the counter is connected to the output terminal of the clock signal generating module, and the output terminal of the counter is connected to the output terminal of the clock signal generating module. The output end is connected with the input end of the decoder, and the output end of the decoder is connected with the input end of the first relay. Among them, when the clock signal generating module outputs a clock signal to the counter, the counter will be incremented by one, and then a new control signal will be obtained after decoding by the decoder, so that the originally closed normally open contact in the first relay is disconnected, At the same time, a new set of normally open contacts is closed to complete the adjustment of the magnification of the second amplifying module. reduced on the basis of .

Wherein, in the embodiment of the present invention, the above-mentioned clock signal triggering module includes a comparator and a monostable circuit (as a preferred example, the monostable circuit may be a monostable flip-flop), the comparator's The input terminal is connected to the output terminal of the maximum value capture module, the output terminal of the comparator is connected to the input terminal of the monostable circuit, and the output terminals of the monostable circuit are respectively connected to the clock signal generation module The input terminal is connected with the input terminal of the capture reset module. Wherein, the comparator compares the output value of the maximum value capture module with a preset value, and when the output value of the maximum value capture module is greater than or equal to the preset value, sends the output value to the monostable The circuit outputs a control signal, and the monostable circuit outputs a clock trigger signal according to the control signal, and then adjusts the magnification of the second amplifying module through the clock signal generating module and the range switching module, and at the same time passes the capture reset module to the maximum value capture module. The captured value is zeroed.

Among them, in the embodiment of the present invention, in order to facilitate the completion of the debugging of each module in the current measurement auxiliary device in the design stage of the current measurement auxiliary device, the current measurement auxiliary device further includes: a control switch and a trigger button. Wherein, the first contact of the control switch is connected to the input end of the clock signal generating module, the second contact of the control switch is connected to the output end of the clock signal trigger module, and the third contact of the control switch is connected to the output end of the clock signal trigger module. The three contacts are connected with the trigger button, one end of the contact link of the control switch is connected with the first contact, and the other end is connected with the second contact or the third contact.

That is, in the embodiment of the present invention, the connection between the clock signal trigger module and the clock signal generation module can be disconnected by controlling the control switch, and the trigger button is connected to the input end of the clock signal generation module. In this way, every time the trigger button is pressed, the clock signal generation module will receive a clock trigger signal, and generate and output a clock signal according to the received clock trigger signal, so that the range switching module can send the clock signal to each constant of the second amplifying module according to the clock signal signal. The control end of the switch sends a control signal to control the second amplifying module to reduce the magnification until the debugging of all the magnifications of the second amplifying module is completed. Of course, it can be understood that when the debugging is completed, the control switch will be controlled to disconnect the trigger button and the input terminal of the clock signal generation module, and the clock signal trigger module and the clock signal generation module will be connected to complete the load current. automatic measurement.

Next, the specific structures of the capture reset module and the clock signal generation module will be described with reference to the relevant drawings.

As shown in FIG. 6 , the above capture reset module includes: a first diode (ie, D ₃ in FIG. 6 ), a second diode (ie, D ₄ in FIG. 6 ), and an RC circuit (ie, D 4 in FIG. 6 ) R ₁₄ , R ₁₅ and C ₁₃ ), a triode (ie, Q ₁ in FIG. 6 ), a third diode (ie, D ₂ in FIG. 6 ), a first filter capacitor (ie, C ₉ in FIG. 6 ), The second relay (ie R ₉ in FIG. 6 ) and the first resistor (ie R ₁₀ in FIG. 6 ).

Wherein, the anode of the first diode is connected to the output end of the power-on reset circuit (the power-on reset circuit can be the power-on reset circuit of the current measurement auxiliary device, which can be implemented by the current general power-on reset circuit) , so as to reset the maximum value capture module when the current measurement auxiliary device is powered on; the anode of the second diode is connected to the output end of the clock signal trigger module, so as to receive the clock signal trigger module output by the clock signal trigger module The maximum value capture block is reset when the signal is activated.

The cathode of the first diode and the cathode of the second diode are both connected to the first end of the RC circuit, the second end of the RC circuit is connected to the base of the triode, and the RC circuit is In order to prevent the base of the triode from being affected by high-frequency noise; the collector of the triode is respectively connected to the anode of the third diode and the negative control end of the second relay, and the third diode The cathode, the first terminal of the first filter capacitor, and the positive control terminal of the second relay are all connected to the output terminal of a power supply (ie, VCC in FIG. 6 ), and the first contact of the second relay is connected to The first input port of the reset signal input end of the maximum value capture module is connected, the second contact of the second relay is connected to the second input port of the reset signal input end of the maximum value capture module, and the second relay The third contact of the first resistor is connected to the first end of the first resistor, and the second end of the first resistor, the second end of the first filter capacitor, and the emitter of the triode are all grounded.

It should be noted that the first contact of the second relay and the second contact of the second relay are a group of normally open contacts of the second relay, and the third diode provides the second relay when the triode is turned off. Freewheeling loop, and when the anode of the first diode receives the reset signal output by the power-on reset circuit, or the anode of the second diode receives the clock trigger signal output by the clock signal trigger module, the second relay The first contact is conductive with the second contact of the second relay, that is, the switch SW1 in FIG. ₃ is closed, so as to discharge the capacitor _C1 in FIG. 3, and finally make V _out in FIG. The maximum value of the output voltage signal) is 0, that is, the capture value of the maximum value capture module is reset to zero.

As shown in FIG. 7 , the above clock signal generating module includes: an operational amplifier (ie U ₁₁ in FIG. 7 ), an inverting reference voltage generating circuit (ie R ₅₆ , R ₅₈ and C ₄₈ in FIG. 7 ), a second resistor (ie R ₅₄ in FIG. 7 ), a third resistor (ie, R ₅₁ in FIG. 7 ), a second filter capacitor (ie, C ₄₃ in FIG. 7 ), and a third filter capacitor (ie, C ₄₄ in FIG. 7 ) and a pull-up resistor (ie, R ₆₃ in Figure 7).

Specifically, the negative input terminal of the above-mentioned operational amplifier is connected to the output terminal of the inverting reference voltage generating circuit, and the positive input terminal of the operational amplifier is respectively connected to the first terminal of the second resistor and the output terminal of the third resistor. The first end is connected, the second end of the second resistor is connected to the first contact of the control switch, the second end of the third resistor is respectively connected to the first end of the pull-up resistor, the operation The output end of the amplifier is connected to the input end of the range switching module, the power supply end of the operational amplifier, the second end of the pull-up resistor, the first end of the second filter capacitor and the third filter capacitor The first end of the 1 is connected to the output end of a power supply (ie, VCC in FIG. 7 ), the ground end of the operational amplifier, the second end of the second filter capacitor and the second end of the third filter capacitor are grounded.

It should be noted that the above-mentioned inverting reference voltage generation circuit is mainly used to set the inverting reference voltage of the operational amplifier, the second resistor and the third resistor are mainly used to set the hysteresis voltage of the operational amplifier; the pull-up resistor is mainly a clock signal generation module The outputs provide pull-ups. Specifically, when the clock signal trigger module inputs a clock trigger signal to the second end of the second resistor (the clock trigger signal is shaped like a triangular wave), the clock signal generation module shown in FIG. 7 can transform the clock trigger signal into a square wave clock signal , output to the range switching module to adjust the magnification of the second amplifying module.

It is worth mentioning that the current measurement auxiliary device of the embodiment of the present invention is realized by pure hardware, has high operational reliability, and can accurately measure the effective value and the maximum value of the voltage across the current sampling resistor, so as to facilitate the sampling based on the current sampling resistance. The resistance value of the resistor can quickly and easily obtain the load current of the power supply under test.

The above-mentioned embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand: The technical solutions recorded in each embodiment are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the various embodiments of the present invention, and are It should be included within the protection scope of the present invention.

Claims (10)

1. A current measurement auxiliary device is characterized in that, comprising: a current sampling resistor, which is connected in series to the load circuit of the target power supply under test; a first amplifying module, wherein two input ends of the first amplifying module are respectively connected to both ends of the current sampling resistor, and the first amplifying module performs differential amplification processing on the voltage signals at both ends of the current sampling resistor; a second amplifying module, the input end of the second amplifying module is connected to the output end of the first amplifying module, and the second amplifying module performs operational amplification processing on the voltage signal output by the first amplifying module; The maximum value capture module, the input end of the maximum value capture module is connected to the output end of the second amplification module, the maximum value capture module captures the maximum value of the voltage signal output by the second amplification module, and captures the maximum value of the voltage signal output by the second amplification module. The maximum value is used as the output value of the maximum value capture module; an effective voltage acquisition module, the input terminal of the effective voltage acquisition module is connected to the output terminal of the second amplification module, and the effective voltage acquisition module acquires and displays the effective value of the voltage signal output by the second amplification module; A maximum voltage acquisition module, the input terminal of the maximum voltage acquisition module is connected to the output terminal of the maximum value capture module, and the maximum voltage acquisition module acquires and displays the output value of the maximum value capture module. 2 . The current measurement auxiliary device according to claim 1 , wherein the second amplifying module comprises a non-inverting amplifying circuit, and the input end of the non-inverting amplifying circuit is connected to the output end of the first amplifying module, so the The output end of the non-inverting amplifier circuit is respectively connected with the input end of the effective voltage acquisition module and the input end of the maximum value capture module; The feedback branch of the non-inverting amplifier circuit includes a first feedback resistor, and multiple feedback resistor units connected in series with the first feedback resistor, the multiple feedback resistor units are connected in parallel with each other, and the feedback resistor unit includes a first feedback resistor unit. Two feedback resistors and a normally open switch connected in series with the second feedback resistor; Wherein, when the current measurement auxiliary device is in the working state, the normally open switch of one feedback resistance unit in the plurality of feedback resistance units is in the closed state. 3. The current measurement auxiliary device according to claim 2, wherein the current measurement auxiliary device further comprises: a clock signal trigger module, the input end of the clock signal trigger module is connected with the output end of the maximum value capture module, the clock signal trigger module compares the output value of the maximum value capture module with a preset value, and When the output value of the maximum value capture module is greater than or equal to the preset value, output a clock trigger signal; a clock signal generation module, the input end of the clock signal generation module is connected with the output end of the clock signal trigger module, and the clock signal generation module outputs a clock signal when receiving the clock trigger signal; a range switching module, the input terminal of the range switching module is connected with the output terminal of the clock signal generating module, and the output terminal of the range switching module is connected with the control terminal of each normally open switch of the second amplifying module; a capture reset module, the input end of the capture reset module is connected to the output end of the clock signal trigger module, the reset signal output end of the capture reset module is connected to the reset signal input end of the maximum value capture module, the The capture reset module outputs a reset signal to the maximum value capture module when receiving the clock trigger signal. 4 . The current measurement auxiliary device according to claim 3 , wherein the current measurement auxiliary device further comprises: a control switch and a trigger button, the first contact of the control switch and the clock signal generation module’s first contact. 5 . The input end is connected, the second contact of the control switch is connected to the output end of the clock signal trigger module, the third contact of the control switch is connected to the trigger button, the contact link of the control switch is connected One end is connected with the first contact, and the other end is connected with the second contact or the third contact. 5 . The current measurement auxiliary device according to claim 3 , wherein the clock signal triggering module comprises a comparator and a monostable circuit, and an input end of the comparator and an output end of the maximum value capturing module connection, the output end of the comparator is connected with the input end of the monostable circuit, and the output end of the monostable circuit is respectively connected with the input end of the clock signal generation module and the input end of the capture reset module connect; Wherein, the comparator compares the output value of the maximum value capture module with a preset value, and when the output value of the maximum value capture module is greater than or equal to the preset value, sends the output value to the monostable The circuit outputs a control signal, and the monostable circuit outputs a clock trigger signal according to the control signal. 6 . The current measurement auxiliary device according to claim 3 , wherein the normally open switch is a group of normally open contacts of the first relay. 7 . 7. The current measurement auxiliary device according to claim 6, wherein the range switching module comprises: a counter and a decoder, the input end of the counter is connected with the output end of the clock signal generating module, and the The output end of the counter is connected with the input end of the decoder, and the output end of the decoder is connected with the input end of the first relay. 8 . The current measurement auxiliary device according to claim 3 , wherein the capture reset module comprises: a first diode, a second diode, an RC circuit, a triode, a third diode, a first filter capacitor, second relay and first resistor; Wherein, the anode of the first diode is connected to the output terminal of the power-on reset circuit, the anode of the second diode is connected to the output terminal of the clock signal trigger module, and the anode of the first diode is connected to the output terminal of the clock signal trigger module. The cathode and the cathode of the second diode are both connected to the first end of the RC circuit, the second end of the RC circuit is connected to the base of the triode, and the collectors of the triode are respectively connected to the The anode of the third diode is connected to the negative control terminal of the second relay, and the cathode of the third diode, the first terminal of the first filter capacitor, and the positive control terminal of the second relay are all is connected to the output end of a power supply, the first contact of the second relay is connected to the first input port of the reset signal input end of the maximum value capture module, and the second contact of the second relay is connected to the maximum The second input port of the reset signal input end of the value capture module is connected, the third contact of the second relay is connected to the first end of the first resistor, the second end of the first resistor, the first The second end of the filter capacitor and the emitter of the triode are both grounded. 9 . The current measurement auxiliary device according to claim 4 , wherein the clock signal generation module comprises: an operational amplifier, an inverting reference voltage generation circuit, a second resistor, a third resistor, a second filter capacitor, a first Three filter capacitors and pull-up resistors; The negative input terminal of the operational amplifier is connected to the output terminal of the inverting reference voltage generating circuit, and the positive input terminal of the operational amplifier is connected to the first terminal of the second resistor and the third resistor respectively. The first end is connected, the second end of the second resistor is connected to the first contact of the control switch, the second end of the third resistor is respectively connected to the first end of the pull-up resistor, the operation The output end of the amplifier is connected to the input end of the range switching module, the power supply end of the operational amplifier, the second end of the pull-up resistor, the first end of the second filter capacitor and the third filter capacitor The first end of the 1 is connected to the output end of a power supply, and the ground end of the operational amplifier, the second end of the second filter capacitor and the second end of the third filter capacitor are all grounded. 10 . The current measurement auxiliary device according to claim 1 , wherein a current sampling resistor is connected in series to the load circuit of each of the multiple tested power supplies, and both ends of the current sampling resistor are connected in series. 11 . A first switch contact is provided, and the target power supply to be tested is any one of a plurality of power supplies to be tested; The two input ends of the first amplifying module are both provided with second switch contacts, and the two second switch contacts of the first amplifying module are in contact with the current sampling resistor in the load circuit of the target power supply under test. The two first switch contacts are in a one-to-one correspondence in contact and conduct.

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