CN108459218B - Test circuit - Google Patents
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- CN108459218B CN108459218B CN201810113887.3A CN201810113887A CN108459218B CN 108459218 B CN108459218 B CN 108459218B CN 201810113887 A CN201810113887 A CN 201810113887A CN 108459218 B CN108459218 B CN 108459218B
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- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
Abstract
The present invention provides a test circuit, comprising: the first end of the voltage drop module is electrically connected with the first power supply module; the reference voltage adjusting module is used for outputting adjustable reference voltage through a reference voltage output end; the first input end of the voltage comparison module is electrically connected with the second end of the voltage drop module, and the second input end of the voltage comparison module is electrically connected with the reference voltage output end; the voltage input end of the second voltage stabilizing module is electrically connected with the second end of the voltage drop module; the trigger signal input end of the control module is electrically connected with the comparison result output end; the signal receiving end of the on-off module is electrically connected with the first control signal output end of the control module, the first connecting end is electrically connected with the voltage stabilizing output end of the second voltage stabilizing module, and the second connecting end is electrically connected with the electronic equipment to be tested.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to a test circuit.
Background
In a factory, after a certain electronic product is produced, performance parameters of the electronic product need to be tested, so that defective products are reduced, and the quality of the electronic product leaving the factory is improved. The performance parameters of the electronic product to be tested generally include input voltage, operating current, and the like. In the testing process, after the electronic product to be tested inputs the testing voltage, the electronic product may generate an overcurrent condition, and the electronic product may be damaged if the overcurrent condition is caused for a long time.
Disclosure of Invention
The present invention aims to solve one of the above problems.
The main objective of the present invention is to provide a test circuit
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the invention provides a test circuit which comprises a first power supply module, a voltage drop module, a reference voltage regulating module, a voltage comparison module, a second voltage stabilizing module, a control module and an on-off module, wherein the first power supply module is used for supplying power; the voltage drop module comprises a first end and a second end, wherein the first end is electrically connected with the first power supply module; the reference voltage adjusting module is used for outputting adjustable reference voltage through a reference voltage output end; the second voltage stabilizing module comprises a voltage input end and a voltage stabilizing output end, wherein the voltage input end is electrically connected with the second end of the voltage drop module; the voltage comparison module comprises a first input end, a second input end and a comparison result output end, wherein the first input end is electrically connected with the second end of the voltage drop module, and the second input end is electrically connected with the reference voltage output end; the control module comprises a trigger signal input end and a first control signal output end, wherein the trigger signal input end is electrically connected with the comparison result output end; the control module is used for sending a conduction control signal to the on-off module through the first control signal output end, and is also used for sending a disconnection control signal to the on-off module through the first control signal output end after the trigger signal input end receives the trigger signal; the on-off module comprises a first connecting end, a second connecting end and a signal receiving end, wherein the signal receiving end is electrically connected with a first control signal output end of the control module, the first connecting end is electrically connected with a voltage stabilizing output end of the second voltage stabilizing module, and the second connecting end is electrically connected with the electronic equipment to be tested; after the signal receiving end receives the conduction control signal, the first connecting end is conducted with the second connecting end; and after the signal receiving end receives the disconnection control signal, the path between the first connecting end and the second connecting end is disconnected.
In addition, the reference voltage adjusting module comprises a second power supply module, a first reference voltage module, a first voltage stabilizing module and a first variable resistance module, wherein the first reference voltage module comprises a first power supply input end and a first reference voltage output end, the first power supply input end is electrically connected with the second power supply module, and the first reference voltage output end outputs a first reference voltage with a fixed voltage value; the first voltage stabilizing module comprises a first reference potential end, an adjustable end and a reference voltage output end, wherein the first reference potential end is electrically connected with the first reference voltage output end and is used for receiving a first reference voltage, and the voltage difference between the adjustable end and the first reference potential end is a fixed value; the first variable resistance module comprises a first fixed end, a second fixed end and a first sliding end, wherein the first fixed end is electrically connected with the reference voltage output end, the second fixed end is electrically connected with the first reference potential end, and the first sliding end is electrically connected with the adjustable end; the resistance between the first sliding end and the first fixed end is adjustable.
In addition, the reference voltage regulation module further includes a first resistor and a second resistor, wherein the first fixed end is electrically connected to the reference voltage output end, including: the first fixed end is electrically connected with one end of a first resistor, and the other end of the first resistor is electrically connected with a reference voltage output end; the second fixed terminal is electrically connected to the first reference potential terminal, and includes: the second fixed end is electrically connected with one end of a second resistor, and the other end of the second resistor is electrically connected with the first reference voltage input end.
In addition, the test circuit further comprises a first voltage regulating module, wherein the first voltage regulating module comprises an adjustable voltage output end, and the adjustable voltage output end is electrically connected with the second reference potential end.
In addition, the first voltage regulation module further comprises a third power supply module, a fourth power supply module, a second reference voltage module, a third reference voltage module, a second variable resistance module and a third voltage stabilization module; the second reference voltage module comprises a second power supply input end and a second reference voltage output end, wherein the second power supply input end is electrically connected with the third power supply module, and the second reference voltage output end outputs a second reference voltage with a fixed voltage value; the third reference voltage module comprises a third power supply input end and a third reference voltage output end, wherein the third power supply input end is electrically connected with the fourth power supply module, and the third reference voltage output end outputs a third reference voltage with a fixed voltage value; the second variable resistance module comprises a third fixed end, a fourth fixed end and a second sliding end, wherein the third fixed end is electrically connected with the second reference voltage output end, the fourth fixed end is electrically connected with the third reference voltage output end, and the resistance between the second sliding end and the fourth fixed end is adjustable; and the third voltage stabilizing module comprises a third reference potential end and an adjustable voltage output end, wherein the third reference potential end is electrically connected with the second sliding end.
In addition, the first voltage regulating module further comprises a third resistor and a fourth resistor; the third stiff end is connected with second reference voltage output electricity, includes: the third fixed end is electrically connected with one end of a third resistor, and the other end of the third resistor is electrically connected with a second reference voltage output end; the fourth stiff end is connected with third reference voltage output electricity, includes: the fourth fixed end is electrically connected with one end of a fourth resistor, and the other end of the fourth resistor is electrically connected with the third reference voltage output end.
In addition, the control module also comprises a second control signal output end; the circuit also comprises a discharging module, wherein the discharging module comprises a discharging control signal input end, a signal input end to be discharged and a grounding end, the discharging control signal input end is electrically connected with the second control signal output end, the signal input end to be discharged is electrically connected with the second connecting end, and the grounding end is grounded; and the signal input end to be discharged is used for being conducted with the grounding end after the discharge control signal input end receives the discharge control signal.
According to the technical scheme provided by the invention, the test circuit is provided, when the electronic equipment to be tested is tested by the test circuit, on one hand, a power supply circuit for the electronic equipment to be tested can be disconnected when the input current of the electronic equipment to be tested is greater than the nominal maximum input current, so that the electronic equipment to be tested is prevented from being damaged due to the overcurrent phenomenon; on the other hand, because the reference voltage output by the reference voltage adjusting module is adjustable, the electronic equipment to be tested with different nominal maximum input currents can be tested, and the application range of the test circuit is expanded; in addition, because the output voltage of the first voltage regulating module can be regulated, the voltage input to the reference potential end of the second voltage stabilizing module can be regulated, that is, the second voltage stabilizing module can provide different power supply voltages for the electronic device to be tested, so as to test whether the electronic device to be tested can normally work under different power supply voltages.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a test circuit provided in embodiment 1 of the present invention;
fig. 2 is another schematic structural diagram of a test circuit provided in embodiment 1 of the present invention;
fig. 3 is a schematic structural diagram of a reference voltage regulation module according to embodiment 1 of the present invention;
fig. 4 is another schematic structural diagram of a reference voltage regulation module according to embodiment 1 of the present invention;
fig. 5 is a schematic structural diagram of a first voltage regulation module according to embodiment 1 of the present invention;
fig. 6 is another schematic structural diagram of the first voltage regulating module according to embodiment 1 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or quantity or location.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.
Example 1
The embodiment provides a test circuit, as shown in fig. 1, which includes a first power module, a voltage drop module, a reference voltage adjusting module, a voltage comparing module, a second voltage stabilizing module, a control module, and an on-off module, where the first power module is configured to provide a power; the voltage drop module comprises a first end and a second end, wherein the first end is electrically connected with the first power supply module; the second voltage stabilizing module comprises a voltage input end and a voltage stabilizing output end, wherein the voltage input end is electrically connected with the second end of the voltage drop module; the reference voltage adjusting module is used for outputting adjustable reference voltage through a reference voltage output end; the voltage comparison module comprises a first input end, a second input end and a comparison result output end, wherein the first input end is electrically connected with the second end of the voltage drop module, and the second input end is electrically connected with the reference voltage output end; the control module comprises a trigger signal input end and a first control signal output end, wherein the trigger signal input end is electrically connected with the comparison result output end; the control module is used for sending a conduction control signal to the on-off module through the first control signal output end, and is also used for sending a disconnection control signal to the on-off module through the first control signal output end after the trigger signal input end receives the trigger signal; the on-off module comprises a first connecting end, a second connecting end and a signal receiving end, wherein the signal receiving end is electrically connected with a first control signal output end of the control module, the first connecting end is electrically connected with a voltage stabilizing output end of the second voltage stabilizing module, and the second connecting end is electrically connected with the electronic equipment to be tested; after the signal receiving end receives the conduction control signal, the first connecting end is conducted with the second connecting end; and after the signal receiving end receives the disconnection control signal, the path between the first connecting end and the second connecting end is disconnected.
In this embodiment, the voltage drop module is a device with a determined resistance value, such as a resistor or other devices capable of dividing voltage. For convenience of description, the resistance value of the voltage drop module is denoted as R, and the specific resistance value is not limited.
In this embodiment, the on-off module may include one or more physical switches, one or more virtual switches, one or more other on-off devices, or any combination of the three, and this embodiment is not limited in particular.
In the present embodimentAfter the test circuit is powered on, the first control signal output end of the control module outputs a conduction control signal, and after the on-off module receives the conduction control signal, the first connecting end and the second connecting end of the on-off module are conducted. After the first connecting end and the second connecting end of the on-off module are conducted, the first power supply module can supply power to the voltage drop module, the second voltage stabilizing module, the on-off module and the electronic equipment to be tested. For convenience of explanation, the voltage of the first power module is denoted as UcThe specific voltage value is not limited as long as the voltage within the nominal voltage range can be provided for the electronic device to be tested.
In this embodiment, the second voltage stabilizing module is configured to provide a stable input voltage for the electronic device to be tested, so as to prevent the electronic device to be tested from being damaged due to the fact that the actual input voltage of the electronic device to be tested is not within the range of the rated input voltage of the electronic device to be tested after the electronic device to be tested is connected to the test circuit, and further reduce the influence of the input voltage on current detection.
In this embodiment, after the electronic device to be tested is connected to the test circuit, since the electronic device to be tested may have defective products during production, the actual working current in the loop of the first power module, the voltage drop module, the second voltage stabilizing module, the on-off module and the electronic device to be tested may be greater than the nominal maximum input current I of the electronic device to be testedmaxAn overcurrent phenomenon occurs.
In this embodiment, when testing the electronic device to be tested, the reference voltage V output by the reference voltage adjusting modulerefIs set as Uc-ImaxR, which can be determined by the nominal maximum input current I of the electronic device to be testedmaxAnd (4) setting.
In this embodiment, the first input terminal of the voltage comparison module is an inverting input terminal, and the second input terminal is a non-inverting input terminal. Once the actual input current of the electronic device to be tested is greater than the nominal maximum input current, that is, when the electronic device to be tested is in overcurrent, the voltage input by the inverting input terminal of the voltage comparison module is less than the reference voltage input by the non-inverting input terminal, and the comparison result output terminal of the voltage comparison module outputs a high-level signal. The trigger signal that the trigger signal input of control module received is high level signal, and after the trigger signal input received high level signal, first control signal output exported disconnection control signal. And after the on-off module receives the off control signal, the passage of the first connecting end and the second connecting end of the on-off module is disconnected. It can be seen that, in the embodiment, the test circuit disconnects the power supply path to the electronic device to be tested after the actual working current of the electronic device to be tested is greater than the nominal maximum input current, so that the electronic device to be tested is protected, and the electronic device to be tested is prevented from being damaged.
As an optional implementation manner of this embodiment, the control module may be implemented by a control chip, the trigger signal input end is an input port of the control chip, and the first control signal output end is an output port of the control chip. When testing is carried out, after the control chip is powered on, the control chip inquires whether the trigger signal input end receives a high level signal, and if the high level signal is not received, a conduction control signal is sent to the on-off module through the first signal output end; and if the control chip inquires that the trigger signal input end receives the high-level signal, a disconnection control signal is sent to the on-off module through the first signal output end.
In this alternative embodiment, the control module further includes a second control signal output, the second control signal output being electrically connected to the discharge module. In specific application, the second control signal output end is an output port of the control chip and is used for sending a discharge control signal to the discharge module when the electronic equipment to be tested is over-current or after the test is finished.
As another optional implementation manner of this embodiment, the control module may also be implemented by a control chip and an NE555 chip, where the control chip includes a first control end, and the first control end is electrically connected to a low-level trigger end (2 pins) of the NE555 chip; the high-level trigger end (pin 6) of the NE555 is electrically connected with the comparison result output end of the voltage comparison module, and the output end (pin 3) of the NE555 is used as a first control signal output end and is electrically connected with the signal receiving end of the on-off module. After the control chip is powered on, a first control end of the control chip outputs a high level signal, namely a low level trigger end (pin 2) of the NE555 receives the high level signal, if the high level signal is not over-current, an output end (pin 3) of the NE555 outputs the high level signal, namely the control module sends the high level signal to the on-off module through a first control signal output end to serve as a conduction control signal, and a first connecting end and a second connecting end of the on-off module are conducted; if overcurrent, then NE 555's high level trigger end (6 feet) receive high level signal, then NE 555's output (3 feet) output low level signal, and control module sends low level signal as disconnection control signal to the break-make module through first control signal output promptly, and the first link and the second link of break-make module break off.
In this optional embodiment, when the on-control signal is a high-level signal and the off-control signal is a low-level signal, the on-off module may be an NMOS transistor, a drain (D pole) of the NMOS transistor serves as a first connection end, a source (S pole) of the NMOS transistor serves as a second connection end, and a gate (G pole) of the NMOS transistor serves as a signal input end. After a grid (G pole) serving as a signal input end in the NMOS tube receives a high-level signal sent by an NE555 output end (pin 3), a drain (D pole) serving as a first connection end is conducted with a source (S pole) of a second connection end. After a grid (G pole) serving as a signal input end in the NMOS tube receives a low-level signal sent by an output end of the NE555, a drain (D pole) serving as a first connection end and a source (S pole) serving as a second connection end are disconnected. It should be noted that the voltage U of the high level signal triggering the conduction of the NMOS transistorgThe following conditions are satisfied: Ug-Us>0, and | Ug-Us presents no axial phosphor>| ugs (th) |, where ugs (th) is the turn-on voltage;
in this optional embodiment, the control chip further includes a second control terminal, and the second control terminal is electrically connected to the reset terminal (pin 4) of the NE 555. In the concrete application, after the test, the tester passes through the switch control second control end and outputs low level signal, and after NE 555's reset end (4 feet) received the low level signal that control chip sent, NE 555's output (3 feet) output low level signal, control module sends low level signal as disconnection control signal to the break-make module through first control signal output promptly, and the first link and the second link of break-make module break off.
In this optional embodiment, the control module further includes a discharge control module in addition to the control chip and the NE555 chip, wherein the discharge control module includes a first signal terminal, a second signal terminal and a second control signal output terminal, the first signal terminal is electrically connected to the first control terminal, the second signal terminal is electrically connected to the second control terminal, and the second control signal output terminal is electrically connected to the discharge module. In specific application, when the electronic equipment to be tested is in overcurrent or after the test is finished, the second control signal output end sends a discharge control signal to the discharge module.
As an optional implementation manner of this embodiment, as shown in fig. 2, the test circuit further includes a discharging module, where the discharging module includes a discharging control signal input terminal, a signal input terminal to be discharged, and a ground terminal, the discharging control signal input terminal is electrically connected to the second control signal output terminal, the signal input terminal to be discharged is electrically connected to the second connection terminal, and the ground terminal is grounded; and the signal input end to be discharged is used for being conducted with the grounding end after the discharge control signal input end receives the discharge control signal. In specific application, after the discharging module receives a discharging control signal sent by a second control signal output end of the control module, the discharging module discharges the electronic equipment to be tested so as to prevent residual current from damaging the electronic equipment.
In this optional embodiment, the discharge module may be implemented by a switch module, such as a triode, an MOS transistor, a controllable switch, and the like, but this embodiment is not limited specifically, and it is within the protection scope of the present invention that the input terminal of the signal to be discharged may be conducted with the ground terminal after the input terminal of the discharge control signal receives the discharge control signal.
As an optional implementation manner of this embodiment, as shown in fig. 2, the reference voltage adjusting module includes a second power module, a first reference voltage module, a first voltage stabilizing module, and a first variable resistance module, where the first reference voltage module includes a first power input end and a first reference voltage output end, where the first power input end is electrically connected to the second power module, and the first reference voltage output end outputs a first reference voltage with a fixed voltage value; the first voltage stabilizing module comprises a first reference potential end, an adjustable end and a reference voltage output end, wherein the first reference potential end is electrically connected with the first reference voltage output end and is used for receiving a first reference voltage, and the voltage difference between the adjustable end and the first reference potential end is a fixed value; the first variable resistance module comprises a first fixed end, a second fixed end and a first sliding end, wherein the first fixed end is electrically connected with the reference voltage output end, the second fixed end is electrically connected with the first reference potential end, and the first sliding end is electrically connected with the adjustable end; the resistance between the first sliding end and the first fixed end is adjustable.
In this alternative embodiment, the first fixed end is a high resistance end and the second fixed end is a low resistance end; or the first fixed end is a low-resistance end, and the second fixed end is a high-resistance end. That is, the resistance between the adjustable terminal and the first reference potential terminal may be a resistance between the first sliding terminal and the low resistance terminal, or a resistance between the first sliding terminal and the high resistance terminal, which is not limited in this embodiment.
In this alternative embodiment, the first variable resistance module may be a sliding rheostat, or may also be a mechanical potentiometer or a digital potentiometer, and this embodiment is not particularly limited. As a preferred embodiment, the first variable resistance module is a digital potentiometer, and the digital potentiometer can adjust the resistance value in a numerical control manner, so that the adjustment precision is high.
In this alternative embodiment, the nominal maximum resistance value of the first variable resistance module is denoted as Rmax1That is, the resistance between the first and second fixed terminals is Rmax1A resistance value R between the first sliding end and the first fixing endw1Is adjustable, in particular by one of the following ways:
the first method is as follows: when the first variable resistance module is a mechanical potentiometer, the first sliding end slides along the resistor body to change the resistance value between the first sliding end and the first fixed end;
the second method comprises the following steps: when the first variable resistance module is a digital potentiometer, the resistance value between the first sliding end and the first fixed end can be adjusted in a numerical control mode.
In this alternative embodiment, the voltage difference U between the adjustable terminal and the first reference potential terminalfIs a fixed value, e.g. when the first voltage regulation block is implemented by NCP3335, the potential difference U between the adjustable terminal and the first reference potential terminalfIt was 1.25V. Voltage U output by first reference voltage moduler1And the voltage value output by the first voltage stabilizing module is raised by connecting the first reference potential end of the first voltage stabilizing module.
In this alternative embodiment, since the potential difference between the adjustable terminal and the first reference potential terminal is fixed and the resistance between the adjustable terminal and the first reference potential terminal is adjustable, the current on the first variable resistance module varies with the variation of the resistance between the adjustable terminal and the first reference potential terminal, and the voltage output by the reference voltage output terminal also varies accordingly.
In the embodiment, the reference voltage V output by the reference voltage regulating modulerefThe resistance between the first variable resistance module and the first fixed end can be adjusted by adjusting the resistance, so that the electronic equipment to be tested with different nominal maximum input currents can be tested, and the application range of the test circuit is expanded.
As a preferred implementation manner of this embodiment, the reference voltage adjusting module further includes a first resistor and a second resistor; the first fixed end is electrically connected with the reference voltage output end and comprises: the first fixed end is electrically connected with one end of a first resistor, and the other end of the first resistor is electrically connected with a reference voltage output end; the second fixed terminal is electrically connected to the first reference potential terminal, and includes: the second fixed end is electrically connected with one end of a second resistor, and the other end of the second resistor is electrically connected with the first reference potential end.
In the preferred embodiment, the first fixed terminal passes through a first resistor R as shown in FIG. 31Connected with the reference voltage output end of the first voltage stabilizing module, and the second fixed end of the first voltage stabilizing module is connected with the reference voltage output end of the second voltage stabilizing module through a second resistor R2And the reference potential end of the first voltage stabilizing module is connected. Through setting up first resistance and second resistance, can prevent that the actual operating current of first variable resistance module is too big, causes the device to damage.
In the preferred practiceIn the way that in the above-mentioned mode,
it can be seen that when R isw1When the resistance between the first sliding end and the second fixed end is 0, namely the resistance between the first sliding end and the second fixed end is minimum, the reference voltage V actually output by the reference voltage output endrefAt most, is
When R isw＝Rmax1When the resistance between the first sliding end and the second fixed end is maximum, the reference voltage V actually output by the reference voltage output endrefAt a minimum, is
In designing a circuit in detail, the nominal maximum input current I of different batches of electronic devices to be tested is assumedmaxIn the range of I1～I2Then, to ensure that all electronic devices with a maximum input current nominally within this range can be tested, the reference voltage VrefThe adjustable range is at least ensured at (U)c-I2*R)～(Uc-I1R), i.e. it is necessary to guarantee:
it can be seen that, in the process of actually designing the circuit, the first reference voltage U output by the first reference voltage module is changedr1First resistance R1A second resistor R2And a first variable resistance module R having a different nominal maximum resistance valuemax1The voltage range that the reference voltage adjustment module actually can adjust can be changed. Under the condition that the actually adjustable voltage range of the reference voltage adjusting module is fixed, the resistance R between the first sliding end and the first fixed end of the first variable resistance module is adjustedw1The reference voltage V actually output by the reference voltage regulating module can be changedrefDue to reference electricityReference voltage V output by voltage regulation modulerefThe adjustable test circuit can detect whether the electronic equipment to be tested with different nominal maximum input currents is over-current or not, and the application range of the test circuit is expanded.
As an optional implementation manner of this embodiment, as shown in fig. 4, the test circuit further includes a first voltage adjusting module, where the first voltage adjusting module includes an adjustable voltage output terminal; the second voltage stabilizing module further comprises a second reference potential end which is electrically connected with the adjustable voltage output end. In specific application, because the voltage output by the first voltage regulating module through the adjustable voltage output end is adjustable, and the adjustable voltage output end of the first voltage regulating module is electrically connected with the second reference potential end of the second voltage stabilizing module, the voltage value output by the first voltage regulating module can raise the voltage value output by the voltage stabilizing output end of the second voltage stabilizing module, that is, the voltage value output by the voltage stabilizing output end of the second voltage stabilizing module can change along with the change of the voltage value output by the first voltage regulating module. In the testing process, the voltage value output by the voltage stabilizing output end is adjusted through the first voltage adjusting module, so that the power supply voltage of the electronic equipment to be tested can be adjusted, and whether the electronic equipment to be tested can normally work within a certain input voltage range or not can be tested.
As an optional implementation manner of this embodiment, as shown in fig. 5, the first voltage regulating module includes a third power module, a fourth power module, a second reference voltage module, a third reference voltage module, a second variable resistance module, and a third voltage stabilizing module; the second reference voltage module comprises a second power supply input end and a second reference voltage output end, wherein the second power supply input end is electrically connected with the third power supply module, and the second reference voltage output end outputs a second reference voltage with a fixed voltage value; the third reference voltage module comprises a third power supply input end and a third reference voltage output end, wherein the third power supply input end is electrically connected with the fourth power supply module, and the third reference voltage output end outputs a third reference voltage with a fixed voltage value; the second variable resistance module comprises a third fixed end, a fourth fixed end and a second sliding end, wherein the third fixed end is electrically connected with the second reference voltage output end, the fourth fixed end is electrically connected with the third reference voltage output end, and the resistance between the second sliding end and the fourth fixed end is adjustable; and the third voltage stabilizing module comprises a third reference potential end and an adjustable voltage output end, wherein the third reference potential end is electrically connected with the second sliding end. In this alternative embodiment, the voltage value output by the first voltage regulating module may be regulated by regulating the second sliding terminal of the second variable resistance module.
In this alternative embodiment, the third fixed end is a high-resistance end of the second variable-resistance module, and the fourth fixed end is a low-resistance end of the second variable-resistance module; alternatively, the third fixing end is a low resistance end of the second variable resistance module, and the fourth fixing end is a high resistance end of the second variable resistance module, which is not specifically limited in this embodiment.
In this alternative embodiment, the second variable resistance module may be a sliding rheostat, or may also be a mechanical potentiometer or a digital potentiometer, and this embodiment is not particularly limited. As a preferred embodiment, the second variable resistance module is a digital potentiometer, and the digital potentiometer can adjust the resistance value in a numerical control manner, so that the adjustment precision is high.
In this alternative embodiment, the resistance value R between the second sliding end and the fourth fixed endw2Is adjustable, in particular by one of the following ways:
the first method is as follows: when the second variable resistance module is a mechanical potentiometer, the second sliding end slides along the resistor body to change the resistance value between the second sliding end and the fourth fixed end;
the second method comprises the following steps: when the second variable resistance module is a digital potentiometer, the resistance value between the second sliding end and the fourth fixed end can be adjusted in a numerical control mode.
In this alternative embodiment, only the third fixed terminal is taken as a high-resistance terminal and the fourth fixed terminal is taken as a low-resistance terminal for the following description, and for convenience of description, the second reference voltage output by the second reference voltage module is denoted as Ur2And the third reference voltage output by the third reference voltage module is recorded as Ur3Then the second reference voltage is outputtedThe voltage difference between the terminal and the third reference voltage output terminal is Ur2-Ur3And the nominal maximum resistance value of the second variable resistance module is recorded as Rmax2When the resistance between the second sliding end and the fourth fixed end is recorded as Rw2When the voltage output by the second sliding end is equal to
It can be seen that the output voltage of the second sliding terminal can be adjusted by adjusting the resistance of the second sliding terminal connected to the second variable resistance module.
In this alternative embodiment, the first voltage regulation module further comprises a third resistor and a fourth resistor; the third stiff end is connected with second reference voltage output electricity, includes: the third fixed end is electrically connected with one end of a third resistor, and the other end of the third resistor is electrically connected with a second reference voltage output end; the fourth stiff end is connected with third reference voltage output electricity, includes: the fourth fixed end is electrically connected with one end of a fourth resistor, and the other end of the fourth resistor is electrically connected with the third reference voltage output end.
In a specific application, as shown in fig. 6, the third fixed end is connected to the second reference voltage output end through the third resistor, and the fourth fixed end is connected to the third reference voltage output end through the fourth resistor. For convenience of illustration, the third resistor is set to R3The fourth resistor is set to R4The voltage value output by the second sliding terminal is
It can be seen that the second reference voltage U output by the second reference voltage module is changedr2A third reference voltage U output by the third reference voltage moduler3And a nominal maximum resistance value R of the second variable resistance modulemax2A third resistor R3A fourth resistor R4The voltage value output by the second sliding terminal can be changed, and the above parameters can be changed according to actual requirements when a circuit is designed, which is not specifically limited in this embodiment. At Ur2、Ur3、Rmax2、R3And R4All determined in one test circuitBy changing the resistance R between the second sliding end and the fourth fixed end of the second variable resistance modulew2The voltage value output by the second sliding terminal can be changed.
In this alternative embodiment, the third voltage regulation module may be implemented by a voltage regulation chip (e.g., AP2210), or may be implemented by a voltage regulation circuit, which is not specifically limited in this embodiment.
The embodiment provides a test circuit, which, when testing an electronic device to be tested, on one hand, can disconnect a power supply path to the electronic device to be tested when an input current of the electronic device to be tested is greater than a nominal maximum input current, so as to prevent the electronic device to be tested from being damaged due to an overcurrent phenomenon; on the other hand, because the reference voltage output by the reference voltage adjusting module is adjustable, the electronic equipment to be tested with different nominal maximum input currents can be tested, and the application range of the test circuit is expanded; in addition, because the voltage input to the reference potential end of the second voltage stabilizing module can be adjusted, the second voltage stabilizing module can provide different power supply voltages for the electronic device to be tested, so as to test whether the electronic device to be tested can normally work under different power supply voltages.
Example 2
Different from embodiment 1, in this embodiment, the first input terminal of the voltage comparison module is a non-inverting input terminal, and the second input terminal is an inverting input terminal, once the actual input current of the electronic device to be tested is greater than the nominal maximum input current, that is, when the electronic device to be tested is in an overcurrent state, the voltage input by the non-inverting input terminal of the voltage comparison module is less than the reference voltage input by the inverting input terminal, and the comparison result output terminal of the voltage comparison module outputs a low level signal. The trigger signal that the trigger signal input of control module received is low level signal, and after the trigger signal input received low level signal, first control signal output exports disconnection control signal. And after the on-off module receives the off control signal, the passage of the first connecting end and the second connecting end of the on-off module is disconnected.
In addition, the control module in embodiment 1 may be implemented by a control chip, or may be implemented by both the control chip and the NE555, which is different from embodiment 1, that the control module in this embodiment is implemented by the control chip, when the control module is implemented by the control chip, the trigger signal input end is an input port of the control chip, the first control signal output end is an output port of the control chip, when a test is performed, after the control chip is powered on, the control chip queries whether the trigger signal input end receives a low level signal, and if the low level signal is not received, the control chip sends a conduction control signal to the on-off module through the first signal output end; and if the control chip inquires that the trigger signal input end receives a low level signal, a disconnection control signal is sent to the on-off module through the first signal output end.
Otherwise, the process is the same as that in embodiment 1, and the description of this embodiment is omitted.
Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
In addition, functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (3)
1. A test circuit is characterized by comprising a first power supply module, a voltage drop module, a reference voltage regulating module, a voltage comparison module, a second voltage stabilizing module, a control module and an on-off module, wherein,
the first power supply module is used for supplying power;
the voltage drop module comprises a first end and a second end, wherein the first end is electrically connected with the first power supply module;
the second voltage stabilizing module comprises a voltage input end and a voltage stabilizing output end, wherein the voltage input end is electrically connected with the second end of the voltage drop module;
the reference voltage adjusting module is used for outputting adjustable reference voltage through a reference voltage output end;
the voltage comparison module comprises a first input end, a second input end and a comparison result output end, wherein the first input end is electrically connected with the second end of the voltage drop module, and the second input end is electrically connected with the reference voltage output end; the first input end of the voltage comparison module is an inverting input end, the second input end of the voltage comparison module is a non-inverting input end, and when the voltage input by the inverting input end is less than the reference voltage input by the non-inverting input end, the comparison result output end outputs a high level signal as a trigger signal; or, the first input end of the voltage comparison module is an in-phase input end, the second input end is an inverting input end, and when the voltage input by the in-phase input end is less than the reference voltage input by the inverting input end, the comparison result output end outputs a low level signal as a trigger signal;
the control module comprises a trigger signal input end and a first control signal output end, wherein the trigger signal input end is electrically connected with the comparison result output end;
the control module is used for sending a conduction control signal to the on-off module through the first control signal output end, and is also used for sending a disconnection control signal to the on-off module through the first control signal output end after the trigger signal input end receives the trigger signal;
the on-off module comprises a first connecting end, a second connecting end and a signal receiving end, wherein the signal receiving end is electrically connected with a first control signal output end of the control module, the first connecting end is electrically connected with a voltage stabilizing output end of the second voltage stabilizing module, and the second connecting end is electrically connected with the electronic equipment to be tested; after the signal receiving end receives the conduction control signal, the first connecting end is conducted with the second connecting end; after the signal receiving end receives the disconnection control signal, the path of the first connecting end and the path of the second connecting end are disconnected;
the control module also comprises a second control signal output end;
the circuit further comprises a discharging module, wherein the discharging module comprises a discharging control signal input end, a signal input end to be discharged and a grounding end, the discharging control signal input end is electrically connected with the second control signal output end, the signal input end to be discharged is electrically connected with the second connecting end, and the grounding end is grounded; and the signal input end to be discharged is used for being conducted with the grounding end after the discharge control signal input end receives the discharge control signal.
2. The circuit of claim 1, wherein the reference voltage regulation module comprises a second power supply module, a first reference voltage module, a first voltage regulation module, and a first variable resistance module, wherein,
the first reference voltage module comprises a first power supply input end and a first reference voltage output end, wherein the first power supply input end is electrically connected with the second power supply module, and the first reference voltage output end outputs a first reference voltage with a fixed voltage value;
the first voltage stabilizing module comprises a first reference potential end, an adjustable end and a reference voltage output end, wherein the first reference potential end is electrically connected with the first reference voltage output end and is used for receiving the first reference voltage, and the voltage difference between the adjustable end and the first reference potential end is a fixed value;
the first variable resistance module comprises a first fixed end, a second fixed end and a first sliding end, wherein the first fixed end is electrically connected with the reference voltage output end, the second fixed end is electrically connected with the first reference potential end, and the first sliding end is electrically connected with the adjustable end; the resistance between the first sliding end and the first fixed end is adjustable.
3. The circuit of claim 2, wherein the reference voltage adjustment module further comprises a first resistor and a second resistor, wherein,
the first fixed end with reference voltage output end electricity is connected, includes: the first fixed end is electrically connected with one end of the first resistor, and the other end of the first resistor is electrically connected with the reference voltage output end;
the second fixed terminal is electrically connected to the first reference potential terminal, and includes: the second fixed end is electrically connected with one end of the second resistor, and the other end of the second resistor is electrically connected with the first reference voltage input end.
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| CN112327144B (en) * | 2021-01-04 | 2021-05-18 | 北京紫光青藤微系统有限公司 | Measurement circuit for measuring chip through IO pin |
| CN112327145B (en) * | 2021-01-04 | 2021-05-18 | 北京紫光青藤微系统有限公司 | Measurement circuit for measuring chip through IO pin |
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| CN102609065A (en) * | 2011-01-19 | 2012-07-25 | 鸿富锦精密工业（深圳）有限公司 | Over-current protection device |
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| CN108469582B (en) * | 2018-02-05 | 2020-09-08 | 天地融电子（天津）有限公司 | Test circuit |
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| US6194842B1 (en) * | 1997-04-23 | 2001-02-27 | Magnetek, S.P.A. | Supply circuit for discharge lamps with overvoltage protection |
| CN203553913U (en) * | 2013-10-11 | 2014-04-16 | 深圳市创维群欣安防科技有限公司 | Main controller overvoltage protection circuit and large-screen splicing system |
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